Functions of Electronic Fuel Injection or EFI

Although all cars sold today have electronic fuel injection systems, earlier automobiles had carburetors, which were less efficient. Some other types of small engines, such as lawnmowers or rototillers, still use carburetors. Both the carburetor and the electronic fuel injection system are mechanisms that supply fuel to the engine.
The first fuel injection systems were throttle body fuel injection systems, or single point systems, which had an electrically controlled fuel injector valve. Later, these were replaced by more efficient multi-port fuel injection systems, which have a separate fuel injector for each cylinder. The latter design is better at metering out fuel accurately to each cylinder, and also provides for a faster response.
Although electronic fuel injection is much more complicated than a carburetor, it is much more efficient. The injector is a type of valve that is controlled electronically, which opens and closes and supplies atomized fuel to the engine. It sprays fuel into the intake valves directly in the form of a fine mist. The injector opens and closes rapidly, and the pulse width, or the amount of time it stays open, determines how much fuel goes into the valve. Fuel is supplied to the injectors by a fuel rail.
Several sensors are included as part of the system, to ensure that the correct amount of fuel is delivered to the injectors, and then to the intake valves. These sensors include an engine speed sensor, voltage sensor, coolant temperature sensor, throttle position sensor, oxygen sensor, and airflow sensor. In addition, a manifold absolute pressure sensor monitors the air pressure in the intake manifold to determine the amount of power being generated. 
In a sequential fuel injection system, the injectors open one at a time, in conjunction with the opening of each cylinder. Some other injection systems may open all injectors simultaneously. The sequential option is advantageous because it allows for faster response when the driver makes a rapid change.
The entire injection system is controlled by an electronic control unit (ECU), which functions as a central exchange for information coming in from all the various sensors. The ECU uses this information to determine the length of pulse, spark advance, and other elements. The ECU has several safety features built in, including a fuel cut parameter and top speed parameter.  

Fuel Filter Functions

A car's fuel filter is located along the fuel lines, either in the engine compartment or underneath the car by the fuel tank. It is the responsibility of the fuel filter to trap large particles in the fuel in order to prevent them from getting into the engine. Because of the tremendous force behind the up-and-down motion of the engine's pistons, which compress the air-fuel mixture so that it will burn more efficiently, any large particles in the fuel could potentially cause serious damage to the engine. Large particles in the fuel also have the ability to clog fuel injectors, depriving a cylinder of precious fuel and requiring that the injector be cleaned or replaced. Therefore, maintaining a clean fuel filter is imperative to the performance of a car's engine.
Due to the differences in fuel delivery systems, each fuel filter is different. A carbureted engine, which essentially uses the principle of vacuum to suck fuel into the engine, has a fairly low-pressure fuel system. Fuel in a carbureted system passes through fuel-resistant rubber hoses. The fuel filter is made of metal or plastic, with an inlet tube protruding from one end and an outlet tube protruding from the other; a hose is fastened over each end with a circular clamp.
In a car with electronic fuel injection, the injectors squirt fuel into each cylinder. Fuel in this type of system is kept highly pressurized with the help of a pressure regulator. Due to the high-pressure system, the fuel lines must be made of metal. Sometimes the fuel filter in a high-pressure fuel injected system is placed in a low-pressure section, and may be connected to rubber hoses with hose clamps, much like in a carbureted system. However, the fuel filter in a high-pressure fuel injected system is usually equipped with a threaded fitting on each end that screws into the fuel lines on either side. 
When changing the fuel filter in your car, there are a couple of precautions you need to take. First, in a car with a high-pressure system, you will need to relieve the pressure before disconnecting the fuel lines from the filter. In most cars, this can be accomplished by removing the fuse that controls the fuel pump, and idling the car until it runs out of gas. Another method that works for some cars is to remove the gas cap. Check your shop manual for more specific instructions. 
In order to be sure the fuel filter works correctly, you will also need to take care to place the fuel filter so that the flow travels in the right direction. Most fuel filters mark one side as "in" and the other as "out." The inlet should connect to the fuel lines that come from the fuel tank underneath the back of the car, while the outlet should connect to the fuel lines that can be traced to the engine. Sometimes the fuel filter will have a different kind of fitting on each side, so that it can only be installed in one direction.
Because the fuel filter is one of the key components in protecting the engine from hazardous foreign particles, it is important to replace it regularly. Some mechanics recommend replacing the fuel filter every year during the regularly scheduled tune up, but other mechanics disagree. To be on the safe side, you should replace your fuel filter at least once every two years. Your fuel filter may need more frequent attention if you live in a particularly high-pollution area, or if you put more miles on your car in a year than the average person.  

Maintenance of the Battery

Even a well-maintained car battery will become depleted over time and eventually lead to hard starting. To save wear on your starter and to keep your vehicle in tip-top shape, changing the car battery will be required every three to five years under normal circumstances. In regions of extreme weather, a battery might need replacement more often. Following these easy steps, you can safely remove the old battery and install the new one.
Removing the old battery:
Many automotive chains that sell car batteries will give a customer credit for an old battery because the core is recyclable. Moreover, it is illegal to throw a car battery in the trash in most states, making it convenient to trade in the old battery when you get a new one. If your automotive retailer does not recycle old batteries, contact the Automobile Association of America (AAA) or check their website for battery recycling information in your area.A car battery is filled with corrosive acid that is potentially explosive and can cause serious injury, easily burning through clothes and skin. Do not expose the battery to flame, sparks, or incendiary devices, including cigarettes. Wear protective eyewear such as clear workman’s goggles and/or a face shield with protective clothing. Do not lean over the battery when performing these steps. 
The battery terminals are labeled + (red/positive) and – (black/negative). Disconnect the negative terminal first and flex the cable away from the battery. Next disconnect the positive terminal. Finally disconnect the top clamp that holds the car battery down. Do not lay tools across the top of the battery. A conductive metal might touch both terminals simultaneously causing a short, sparks, or a potential explosion.
A car battery weighs 32 pounds (14.5 kg) or more and should be lifted out of the automobile with extreme care. Do not tip or drop the battery. Many newer batteries are made with a handy strap handle. Battery straps are also available at automotive shops. Alternately, you can lift the car battery straight up and out by holding it at opposite corners. 
Clean the battery cables, pan and clamp. If there is corrosion present (white powder), neutralize it with a mixture of baking soda and water using an old toothbrush.
Installing the new car battery:
When purchasing a new car battery, confirm that the negative and positive terminal posts are on the same side of the battery as your old one. Connecting the battery reversed can cause serious damage to your car. For your own safety, purchase a car battery that has had the electrolyte premixed and added by the retailer, and is already partially charged.
Carefully lower the new car battery into place. Make sure it is sitting flat in the battery pan, and not on the lip. Swing the top clamp into place and secure the battery by tightening down the clamp.
Many new batteries come with a protective plastic cap on each terminal post. Remove the positive plastic cap if present, and smear some petroleum jelly on the terminal post. This will help prevent corrosion. Connect the positive cable and tighten it. Repeat this process for the negative cable. (This is the reverse order of disconnecting the battery.) Be sure to remove all tools before closing the hood.
It’s a good idea to drive the car for thirty minutes or more once the new battery is installed. Highway driving is more helpful than stop and go driving. The battery will charge faster if drains are kept at a minimum, such as air conditioning, stereos and unnecessary lights.
Check the water in your battery periodically, more often during hot weather. Use only distilled water to keep the electrolyte fluid at its proper mark. If the vehicle sits unused for long periods of time, purchasing a Battery Minder or Battery Tender is a good idea. Either product will keep the battery fully charged between uses, extending its life  

Importance of Pressure Plate

The pressure plate is an integral factor in the function of an automobile’s manual transmission. The pressure plate pushes the clutch disc, sometimes called the clutch plate, against the constantly spinning engine flywheel. The clutch disc, therefore, is either stationary or rotating at the same speed as the flywheel. Friction material, similar to that found on brake pads and brake drums, causes the clutch disc to spin at the same speed as the engine flywheel. It is this friction between clutch disc and flywheel that allows the engine torque to drive the wheels. 
Pressure plates are, as the name implies, round, metallic devices containing springs and fingers, or levers, and controlled by the release fork connected to the shifter. All of the clutch components are enclosed in the bell housing of the transmission, between the rear of the engine and the front of the gearboxWhen the driver steps on the clutch pedal, a number of springs in the pressure plate are compressed by multiple — most often three — fingers. This compression of the spring(s) pulls the pressure plate and the clutch disc away from the flywheel and thus prevents the clutch disc from rotating. When the clutch disc is stationary, the driver can shift into the proper gear and release the clutch pedal. When the pedal is let up, the fingers in the pressure plate release their grip and the spring(s) expand to push the pressure plate into the clutch disc, thereby engaging the flywheel. This release process is often called the “clamp load”. 
There are three major types of pressure plates: (1) The Long style which contains nine coil springs for pressure against the flywheel and three thin fingers for release. The Long style plate is used mainly for drag racing. (2) The Borg & Beck style also contains nine coil springs and three fingers. The fingers are wider, however, and the Borg & Beck has the more robust materials and design necessary for street driving. (3) The diaphragm pressure plate is best suited for street use and is, therefore, the most common type found on later-model automobiles. It contains a single Bellville-style spring that applies a more even load from clutch plate to flywheel. Because the single-spring diaphragm is more effective “over-center”, there is also less effort needed by the driver to hold the clutch pedal in the depressed position at a stop.

How to repair and Anti-freeze Leak

The one good thing about an antifreeze leak is that it makes itself apparent very quickly. Your temperature gauge soars, warning lights comes on, and sometimes steam pours from beneath the hood of your car, truck, or SUV. When these things occur, pull to the side of the road and stop the car as soon as safely possible. Continuing to operate a vehicle that has lost its coolant can easily lead to the destruction of its engine.

An antifreeze leak can be either external or internal. If you are experiencing an internal leak, something like a bad head gasket or a cracked engine block, it is best to have the vehicle towed to a mechanic. A broken head gasket or cracked engine block may be leaking antifreeze into a cylinder or your oil crankcase. These are not simple repairs, and will often cost well over $1,000 US Dollars (USD).
An external antifreeze leak is easier to diagnose and repair. First, you should determine where the leak is occurring. The most common sources of leakage are the upper or lower radiator hoses, the radiator cap, the radiator overflow reservoir, or within the radiator itself. Leakage can also take place around the water pump, heater core, and intake manifold gasket.
To diagnose and repair an antifreeze leak, first check the radiator cap. If you are very lucky, and cannot spot any other leaks, then the problem may simply be that the cap has been damaged and is unable to contain the pressure of the hot coolant in the radiator. The solution is to buy a new cap. Remember to wait until the car has cooled before removing the old cap, as a facefull of boiling antifreeze is a less than pleasant experience.
Next on the list is a check of the upper and lower radiator hoses and hose clamps. You should easily be able to tell if a hose is cracked or split, as the coolant will either be dripping out or spurting like a fountain. Replacing the upper hose is a relatively quick job. Replacing the lower hose is often a difficult and dirty task. If the hoses appear to be fine, check the clamps.
Like all mechanical parts, hose clamps can weaken and loosen over time, leaving tiny gaps and spaces around intake and outflow openings. Just replace the clamps with new ones. Replacement of the upper hose clamps is a breeze, as they are easily accessible. Again though, due to the cramped engine compartments of virtually all late-model cars, replacement of the lower hose clamps may lead to scraped knuckles and cursing.
The next most common source of an antifreeze leak takes place in the radiator itself. You can try the quick fix, which is to pour in a can of one of the many additives that profess to stop pinhole radiator leaks. Sometimes this will work, and sometimes it won’t. A radiator can be damaged by internal corrosion, flying rocks or debris, and sometimes simply by age itself. In any case, an additive repair is usually a temporary solution, and eventually your radiator will either need to be repaired or replaced by a professional.
The final simple repair for an antifreeze leak lies in your radiator’s plastic overflow reservoir. This reservoir takes in coolant when it becomes too hot. After it has cooled, it is sucked back into the radiator. If there is a hole or crack in the reservoir, you will loose coolant on a regular basis. The choices are either to try and repair the crack or hole with glue, or purchase a new reservoir.
Fixing a leaking water pump, heater core, or intake manifold gasket is more complex. Unless you are a qualified mechanic, they fall into the “don’t try this at home” category. The odds are, unless you are very knowledgeable in automotive repair, you will cause more damage than already exists.

Importance of Cylinder Block

The engine block is the linchpin of vehicles which run on internal combustion, providing the powerhouse for the vehicle. The engine block is termed a block because it is usually a solid cast car part, housing the cylinders and their components inside a cooled and lubricated crankcase. The engine block is designed to be extremely strong and sturdy, because failure of the engine block results in failure of the car, which will not function until the engine block is replaced or repaired.

The engine block is typically made of cast iron, although in the late 1990s engine blocks made from plastic and other experimental materials were being used in prototype cars with the hope of developing more lightweight, efficient vehicles. A cast iron engine block can comprise a substantial portion of the weight of the car, and usually requires multiple people to be removed and worked on safely.
Working from the outside in, the engine block starts with a solid metal outside, designed to seal everything inside. A number of channels and passages inside comprise the cooling jacket, and are designed to deliver water from the radiator to all the hot sections of the engine, preventing overheating. After the water is circulated in the engine, it returns to the radiator to be cooled by the fan and sent back through the engine.  
The core of the engine block is the cylinders, capped by the cylinder head. The number of cylinders determines the size and placement of the engine block, with most cars having between four and eight cylinders. These cylinders house pistons, which provide motive energy for the vehicle through a series of controlled explosions inside the cylinders which push the pistons out, moving the crankshaft of the vehicle.  
Attached to the bottom of the engine block is the oil pan, which seals in the lubricating oil for the engine. Periodically the oil for the car must be changed, and the oil pan is drained and refilled to remove the older oil, which has lost viscosity and picked up impurities.  
The engine block is the collective term which refers to the crankcase and all the components which fill it, including gaskets, valves, and seals. Because of the importance of the engine block in the functioning of the car, it is recommended that drivers perform regular maintenance on their vehicles to prevent damage to internal parts which can be caused by overheating, insufficient oil, and other easily preventable situations. 
The engine block becomes extremely hot during normal operations, and drivers should be cautious about touching it until it has cooled sufficiently. Some enterprising drivers and aspiring chefs have also experimented with cooking foods such as baked potatoes on the engine block, although this is not generally recommended because should the food may become dislodged during cooking, potentially causing damage to the engine.    

Familiarize Six Cylinder and Four Cylinder

In a four-stroke engine, a series of movements causes fuel to be converted into forward motion. All else being equal, the difference between a 4-cylinder and 6-cylinder engine is that the latter produces more power. This is due to the two extra cylinders that create additional piston thrust.
In a basic engine design, pistons travel down cylinder sleeves or chambers, allowing intake valves to open. Intake valves let fuel and air enter the cylinders, while rising pistons compress these gasses. Spark plugs ignite the compressed gas, causing explosions that drive the pistons back down.
The next rise of the pistons coincides with exhaust valves opening to clear the chambers. The timing of the pistons is staggered so that one pair rises while another falls. Pistons are connected to rocker arms, which turn a crankshaft; the crankshaft turns the wheels, thereby converting fuel into motion.In a 4-cylinder engine, there are four pistons rising and falling in four chambers. A 6-cylinder engine features six pistons and produces a theoretical 50% more power than the same 4-cylinder engine. While a 4-cylinder engine might hesitate when you press on the gas, a 6-cylinder will tend to be more responsive, with greater get-up-and-go. The 4-cylinder engine is standard in smaller cars, as the relatively light weight of the vehicle makes it an economical choice with plenty of power for average motoring needs. Many models include a 6-cylinder engine upgrade option. The 6-cylinder engine is standard on passenger cars, vans, small trucks and small to midsize sports utility vehicles (SUVs). Some of these models may also offer alternate engine designs as options. Standard trucks and larger SUVs commonly feature an 8-cylinder engine. These heavier vehicles are used for towing and carrying substantial weight.Though more cylinders equal more power when comparing the same engine models, there are exceptions when comparing different engines. Improved engine designs over the years have resulted in substantial gains. This has made 4-cylinder engines more powerful than they were a decade ago, and 8-cylinder engines more fuel-efficient than they once were. In short, a 6-cylinder engine from 1993 that’s still running strong might nevertheless have less power than a recently designed 4-cylinder engine. In addition, a new 8-cylinder engine might get better gas mileage than the older 6-cylinder engine. If deciding between a 4 and 6-cylinder engine on a new vehicle, there are a few considerations. The smaller engine will be less expensive and should get slightly better gas mileage. The disadvantage is a lack of power that might factor in more for commuters and travelers. For hilly or mountainous areas, the 6-cylinder engine would likely be a better choice. If interested in towing substantial weight, such as a powerboat or house trailer, consider an 8-cylinder motor. Note that not all 4-cylinder engines are created equal. Differing technologies can make one engine feel gutless and another peppy. Differences also exist in larger engines of differing designs. The only way to tell if a particular engine will suit your needs is to give it a fair test drive.

Radiator Functions

To understand what a car radiator does, it might help to understand the nature of the internal combustion engine it protects. A car's engine has numerous moving parts, and where there is movement there is friction. Friction creates heat. Motor oil is pumped throughout the engine block to provide some lubrication, but it isn't enough to overcome all of this excess heat energy. As a result, parts of the engine become boiling hot as part of normal operations.
This is where the radiator system comes into play. The engine block must be kept relatively cool to avoid serious problems like overheating and seizure. If the pistons cannot slide freely in their cylinders due to excessive friction, they will eventually snap and cause total engine failure. To prevent this from happening, a mixture of water and anti-freeze is pumped through chambers in the engine block to absorb the excess heat and draw it away from vital areas.When this superheated engine coolant exits the engine block, it returns to the radiator through a large rubber hose. A car's radiator is designed to maximize surface area through a significant number of internal folds and chambers. As the hot engine coolant moves through these nooks and crannies, excess heat is drawn out through the walls of the radiator. An electrical or belt-driven fan may force cooler outside air through the radiator to accelerate this cooling process. As the car moves, the front of the radiator is also cooled by the outside air coming through the car's grill.By the time the superheated engine coolant has made its way through all of the chambers of the radiator, it should be cool enough to make a return trip through the engine block. However, if the coolant flow should be reduced by a blockage or loss of fluid, the engine block will not be cooled down and the remaining engine coolant will boil over. This is why maintaining a full coolant level is so important, especially during hot weather or long drives.A radiator does not contain any electronic parts of its own -- special sensors register the temperature of the coolant as it exits the radiator. Engine coolant does not have to be especially cool in order to be effective, so there is usually a wide range of temperatures considered to be within normal parameters. If anything goes wrong with the radiator itself, such as a leak or broken hose, the operating temperature of the car can reach a dangerous level within minutes. The engine must be allowed to cool down naturally before the vehicle can be driven safely to a mechanic. 

Ignition Switch Functions

A car's ignition switch serves several purposes. First, it allows you to control the power to many of the car's accessories, preventing accessories from running down the car's battery when the car is parked for a long period of time. The ignition switch also serves the far greater purpose of connecting the starter to the battery, allowing the battery to send a powerful surge of electricity to the starter when the car is being started.
The term ignition switch is often used interchangeably to refer to two very different parts: the lock cylinder into which the key is inserted, and the electronic switch that sits just behind the lock cylinder. In some cars, these two parts are combined into one unit, but in other cars they remain separate. It is advisable to check your car's shop manual before attempting to purchase an ignition switch, to ensure that you buy the correct part.
In order to start a car, the engine must be turning. Therefore, in the days before ignition switches, car engines had to be turned with a crank on the front of the car in order to start them. The starter performs this same operation by turning the engine's flywheel, a large, flat disc with teeth on the outer edge. The starter has a gear that engages these teeth when it is powered, rapidly and briefly turning the flywheel, and thus the engine. 
The ignition switch generally has four positions: off, accessories, on, and start. Some cars have two off positions, off and lock; one turns off the car, and the other allows the key to be removed from the ignition. When the key is turned to the accessories position, certain accessories, such as the radio, are powered; however, accessories that use too much battery power, such as window motors, remain off in order to prevent the car's battery from being drained. The accessories position uses the least amount of battery power when the engine is not running, which is why drive-in movie theaters recommend that the car be left in the accessories mode during the movie.
The on position turns on all of the car's systems, including systems such as the fuel pump, because this is the position the ignition switch remains in while the car's engine is running. The start position is spring loaded so that the ignition switch will not remain there when the key is released. When the key is inserted into the ignition switch lock cylinder and turned to the start position, the starter engages; when the key is released, it returns to the on position, cutting power to the starter. This is because the engine runs at speeds that the starter cannot match, meaning that the starter gear must be retracted once the engine is running on its own.  
Either the ignition switch or the lock cylinder may fail in a car, but both circumstances have very different symptoms. When the ignition switch fails, generally the electrical wiring or the plastic housing develops problems. The car may not turn on and/or start when this happens. Also, the spring-loaded start position could malfunction, in which case the starter will not engage unless the key is manually turned back to the on position.  
When the lock cylinder malfunctions, however, the operation of the key itself will become problematic. If the tumblers become stripped, the lock cylinder may be able to turn with any key, or you may be able to remove the key when the car is on. If the tumblers begin to shift, the lock cylinder may not turn. Sometimes the key can be wiggled until the lock cylinder turns, but it is important to remember that this is only a temporary fix.
Replacing an ignition switch can be tricky business, particularly in newer cars, because of the anti-theft devices used in cars. Once the ignition switch is separated from the back of the lock cylinder, the car can be started with a screwdriver, making it vital that this switch be difficult to get to. It is important to consult a shop manual before attempting this kind of repair, as the anti-theft devices may require special tools; attempting to remove an ignition switch without the proper tools can render the car inoperable. 

Familiarize 4 Strokes and 2 Storkes Engine

To understand the mechanical differences between a two stroke and four stroke engine, lets first consider how the four stroke engine works. The four strokes are:
Intake: The piston travels down the cylinder while the intake valve is opened to allow a mixture of fuel and air to enter the combustion chamber.
Compression: The intake valve is closed and the piston travels back up the cylinder thereby compressing the gasses.
Combustion: The spark plug ignites the compressed gas causing it to explode, which forces the piston down.
Exhaust: The piston rises up the cylinder as the exhaust valve is opened, allowing the piston to clear the chamber to start the process over.

Each time the piston rises and falls it turns the crankshaft that is responsible for turning the wheels. This is how fuel is converted into forward motion.
Of note here is that the spark plug only fires once every other revolution. Also, there is a sophisticated set of mechanisms working in synchronization to create the four strokes. A camshaft must alternately tip a rocker arm attached either to the intake or exhaust valve. The rocker arm returns to its closed position via a spring. The valves must be seated properly in the cylinder head to avoid compression leaks. In other words, a symphony of mechanical events occurs.
In the two stroke engine, all four events are integrated into one simple downward stroke, and one upward stroke. Two strokes. Intake and exhaust are both integrated into the compression and combustion movement of the piston, eliminating the need for valves. This is accomplished by an inlet and exhaust port in the wall of the combustion chamber itself. As the piston travels downward from combustion, the exhaust port is exposed allowing the spent gasses to rush out of the chamber. The downward stroke also creates suction that draws in new air/fuel through an inlet located lower in the chamber. As the piston rises again, it blocks off the inlet and port, compressing the gasses at the top of the chamber. The spark plug fires and the process starts over. Significantly, the engine fires on every revolution, giving the two stroke its power advantage.
However, at the lowest point of travel of the piston when the chamber is filling with fuel/air, the exhaust port exposed above allows some fuel/gasses to escape the chamber. This is easily seen with an outboard motorboat, evident by the multicolored oil slick surrounding the engine, but it happens with all two stroke engines. This along with burning oil creates pollution and fuel-efficiency issues.
For these reasons, two stroke engines are reserved for intermittent use, where weight-to-power ratio or orientation issues are important and where mileage isn't primary. Meanwhile manufacturers are looking for ways to add advantages to four stroke motors, making them smaller, lighter and more robust.
To further understand the difference between a two stroke and a four stroke engine let us consider the advantages and disadvantages.
Advantages of the two stroke:

• Has more get-up-and-go because it fires once every revolution, giving it twice the power of a four stroke, which only fires once every other revolution.
• Packs a higher weight-to-power ratio because it is much lighter.
• Is less expensive because of its simpler design.
• Can be operated in any orientation because it lacks the oil sump of a four stroke engine, which has limited orientation if oil is to be retained in the sump.

These attributes make two stroke engines very popular for a variety of uses from dirt bikes, mopeds, jet skis, and small outboard motors, to lawn and garden equipment such as mowers, edgers, leaf blowers, chain saws and hedge trimmers.
But there are other differences between the two stroke and four stroke engines that aren't so favorable, which is why you won't see two stroke engines in cars.
Disadvantages of the two stroke:

• Faster wear and shorter engine life than a four stroke due to the lack of a dedicated lubricating system.
• Requires special two stroke oil ("premix") with every tank of gas, adding expense and at least a minimal amount of hassle.
• Heavily pollutes because of the simpler design and the gas/oil mixture that is released prior to, and in the exhaust (also creates an unpleasant smell).
• Is fuel-inefficient because of the simpler design, resulting in poorer mileage than a four stroke engine.
• Has a high-decibel whine that may exceed legal noise limits in some areas, depending on the product and local applicable laws.

Before purchasing a two stroke product you might check with your local municipality to see if any restrictions apply.   

How to Use a Timing Light

A timing light is a device used to set an automobile's ignition timing. The hand-held device attaches to the vehicle's battery and to the engine's No. 1 spark plug wire. With the engine running, the timing light has a strobe light that lights every time the No. 1 spark plug fires. The light is aimed at the engine's harmonic balancer, which has a series of numbers engraved into it. The numbers represent the amount of degrees before and after the No. 1 cylinder's top dead center position. A chalk mark is placed in the appropriate spot and is illuminated when the light flashes, allowing the timing to be advanced or retarded until the desired reading is obtained.On distributor-equipped engines, there is often a vacuum advance module on the distributor that must be disconnected prior to using a timing light. The timing must be set with the advance disabled, though the vacuum hose must be plugged to prevent a false reading from the timing light. It is important for people to take the reading with the timing light while the engine is operating at the proper speed. The vehicle's manual will contain information pertaining to the correct engine revolutions per minute (RPM) to set the engine timing at.On some performance timing light housings, there is an adjustable advance knob feature. This advance feature allows the timing light to be set at the desired timing degree based on engine RPM. This feature is used when setting a racing engine's timing; it is able to represent the amount of timing that is set in the distributor for any given engine speed. This feature also makes it possible to determine if a distributor is working and is equipped with the correct weights by flashing and signaling the firing of the spark plug and matching the flash to the timing marks on the balancer.

The typical timing light design takes the shape of a pistol. This shape makes it easy to point at the desired area within the engine bay in order to illuminate the timing marks on the bottom of the engine. Some non-traditional light designs are simply straight housings with the wires coming out of the end of the light. These lights are often difficult to use in an automobile engine compartment; however, they are useful when being used on an exposed engine, such as a tractor. While some of the older lights use a wire spring that is actually placed inside the spark plug wire terminal, most modern timing light designs use an inductive pickup that is merely clipped onto the spark plug wire to take the reading.

Transaxle Functions

A transaxle is most commonly found in a front-wheel drive vehicle. This component combines the transmission with the drive axle, hence the term transaxle. This component can be found in both stick shift as well as automatic versions and with any engine from a four- to eight-cylinder. There also are rear-engine transaxle units found in exotic sports cars such as a Porsche and Lamborghini, as well as large vehicles such as a Greyhound bus. Perhaps one of the earliest versions of the transaxle was found in the Volkswagen Beetle. This small, air-cooled rear-engine automobile was one of the longest-produced and best-selling vehicles of all time, surpassing Henry Ford's Model T. The success of the Beetle was responsible for General Motors' attempt at an air-cooled rear engine in the 1960s, the Chevrolet Corvair. In a roll-over test, it was determined the Corvair rolled over too easily and the vehicle was discontinued after much public debate.A benefit of running a transaxle is that there is no drive shaft to wear out or vibrate. Coupling the engine directly to the transaxle allows the entire drive train to be removed from a vehicle as a complete unit. This makes repair and replacement an easy procedure. In a front-wheel drive vehicle, the only limitation to the power the transaxle is able to withstand lies in the steering knuckle's ability to tolerate the power without breaking.
One of the first American vehicles to utilize the transaxle was the Cord 810. This vehicle was touted as being well ahead of its time and was short-lived in spite of above-average performance. The front-wheel drive automobile was absent from the United States automobile manufacturing scene after the demise of the Cord until 1966 when the Oldsmobile Toronado made its debut. The first attempt at a front-wheel drive race car came in 1924 with the Miller 122. This vehicle met with minimal success at the Indianapolis 500.
Facing the fuel shortage of the 1970s, automobile manufacturers in the United States and others worldwide began releasing newly-designed front-wheel drive vehicles in the late 1970s. Although widely hailed as throw-away vehicles, the small front-wheel drive vehicles began to catch on, and as the quality improved, the vehicles began to be accepted as legitimate automobiles by the general public. Today, all vehicle manufacturers worldwide have front-wheel drive vehicles in their new car lineups.  
 

Electronic Control Unit (ECU) Functions

The electronic control unit, also called the ECU, is the brain of the automobile. This small device is typically located behind the glove compartment, underneath the vehicle's dashboard. Modern automobile design utilizes many electric components that determine fuel delivery, transmission shift points and ignition timing, to name only a few. These components take direction from the electronic control unit, which controls all electronic functions within the vehicle's drive train.
Actually a small computer, the electronic control unit takes readings from all of the vehicle's electronic sensors and interprets the vehicle's needs. In order to operate at the peak fuel mileage and performance, the electronic control unit makes continual adjustments to the engine's fuel delivery circuits as well as the ignition timing to provide the proper air and fuel mixture being ignited at the optimal time in the combustion chamber. This ensures the vehicle is operating at the utmost peak power and economy level possible.
Important on-the-fly adjustments are not limited to the vehicle's engine by the electronic control unit. The transmission's torque converter, in an automatic transmission-equipped vehicle, is locked and unlocked according to information received by the electronic control unit. By locking the torque converter, the electronic control unit is able to eliminate fuel-wasting transmission slippage, which equates to higher fuel costs for the owner. The electronic control unit also determines the optimal shift points for the transmission based on feedback received from the engine, which takes advantage of the peak horsepower and torque produced by the engine.
Many of the vehicle's components and engine systems can be monitored by the control unit. The oil condition as well as maintenance schedules are monitored by the unit. By taking readings from sensors within the engine, the unit is able to decipher the proper intervals for scheduled maintenance. When a problem within the drive train is detected, the unit sends a message to the operator via a message board in the instrument cluster.
The electronic control unit provides the proper application of fuel in cold climates to ensure a smooth cold weather start. Trouble-free operation in any weather condition is provided through the system's monitoring of the control unit. Often making adjustments many thousands of times per minute, the control unit is like having a personal mechanic riding along to keep things running smoothly. When there is a problem with any part in the vehicle's electronic system, the control unit is able to flash a code directing the service attention to the correct area.
  

Cylinder Head Functions

A valve head, or cylinder head as it is more commonly called, is a piece of an internal combustion engine that contains and houses the intake and exhaust valves. The head sits on top of an engine directly over the pistons and encloses the combustion chamber. The valve head has an opening known as a valve guide running completely through the valve head.

The valves are located in the bottom of the valve head facing the piston and are held in place by having their stems running up through a valve guide seal. This is located inside of the valve spring. A valve retainer and keeper clip hold the entire component in place.
One of the major concerns when designing a valve head is to plan a cooling system that will prevent overheating. Overheating of the valve head leads to head gasket failure and can even lead to cracking of the head. Water passages are cast into the head as it is manufactured, and they allow coolant to flow through the heads and keep them cool. The water passages align with water passages cast into the engine block. The coolant flows freely between the block and heads and absorbs the heat from the combustion process.
A valve head can be made of cast iron or aluminum. Most modern heads are of aluminum construction due mainly to the lighter weight of the material as compared to iron. Aluminum heads also produce more power due to their ability to absorb the engine heat differently and more effectively than their iron counterparts. The expansion rates of aluminum and cast iron are very different; special head gaskets must be used to allow the two materials to expand and constrict at different rates without damaging the gasket or its seal.
One of the best methods of producing horsepower from an engine is to perform extensive work in the valve pockets and exhaust areas of a valve head. By grinding and smoothing the areas where the intake charge and exhaust flow into and out of the head, the power levels of the engine can be drastically raised. This type of work is known as porting. Even the basic and simple act of matching the intake and exhaust ports to the openings in the corresponding gaskets will gain horsepower. There is a very fine line between improving the flow of a head and ruining the head, which is why this type of work is very expensive to have done by a professional.

Piston Pin Functions

A piston pin, also known as a wrist pin, is a hardened steel pin which connects an engine's piston to a connecting rod. The piston pin is hollow to reduce weight and is held in place with a number of different methods. Most factory-stock piston pin designs rely on a pressed fit with the piston pin being pressed into the connecting rod. High-performance pistons are typically held in place with wire clips or aluminum buttons. When installing a new piston pin it is imperative that the pin be oiled where it passes through the piston. Failure to adequately lubricate the piston pin will result in a seized piston nearly every time. The high heat generated by the connecting rod rotating within the piston causes a dry or inadequately lubricated pin to fall into the piston. This will cause the engine to lock up as the piston locks onto the piston pin. Broken connecting rods and even a broken engine block could also result. 
While most stock piston pins are made of hardened steel, many high-performance applications utilize tool steel pins. These tool steel pins are the strongest and most durable available and can withstand ultra high horsepower. The use of high-quality materials also allows the tool steel piston pins to be made very light weight. This aids in the engine's ability to accelerate at a much faster rate than an equally prepared engine equipped with heavier piston pins.
While most pistons are sold complete with piston pins included, some of the highest-quality racing pistons are sold without pins. This allows the engine builder to purchase the piston pin package which best suits the engine's build characteristics. Nearly every professional engine builder around the world has a unique manner of assembling engines; most will agree, however, that full-floating piston pins are the correct call for a serious performance engine assembly.  
In a stock engine, the piston pins are lubricated and cooled by oil which is splashed or thrown off of the crankshaft as it spins within the engine block. In most normal driving conditions, this is a successful design. In racing or high-performance applications, the engine builder will often incorporate a system of tubes directed toward the bottom of the pistons. These tubes spray oil directly onto the piston pins and the piston's pin bosses, maintaining lubrication and cooling efforts. By keeping the piston pins cool, the pistons are able to generate maximum horsepower without heat-related engine failure. 
  

Valve Functions

A valve guide is a tube that runs through an engine's cylinder head in which the exhaust and intake valves are positioned. The valve guide is typically made of a material, such as bronze, and guides the valve, keeping it straight. As the valve guide wears, the valve stem begins to become loose and oil is able to leak into the combustion chamber. This creates smoke and a loss of power from the engine.
The valve guide is only used for engines using a push rod-type camshaft. For the overhead valve type of engines, the valve guide is not utilized as the cam actually actuates the valves and push rods are not used. The typical valve guide is designed to outlive the engine and thus will never require repair. With proper lubrication and scheduled oil change intervals, the valve guides will remain in peak operational form.
The valve guides are designed to fit the valve stems with a minimal amount of clearance and they use oil that is seeped through the valve guide seal for lubrication. This oil is tasked with the job of controlling the high temperatures of the valve stem through the process of combustion. In aluminum head applications, the valve guides also aid in the prevention of heat damage to the head. The ultra-high heat generated by the combustion chamber is radiated away from the valve stem by the guides.
Perhaps the most expensive method for repairing a worn valve guide is to drive the old guides out of the head with a press and install new guides. This repair method is risky and many heads are damaged beyond repair. Once successfully driven out, the old guide is replaced with a new guide that is pressed into place. Once the new valve guide is in place, it is trimmed to fit and dressed to receive a new valve. This procedure is used primarily on aluminum heads.
Knurling is perhaps the most popular method of repairing a worn guide. This procedure build up the guide and then reams it back to the proper size. Once the guide is repaired with whichever method is chosen, the guide seal is replaced. This is a small rubber cup-like component that pushes down over the valve stem. The seal is pushed onto the guide boss cast into the head and prevents excess oil from entering the guide.   

Familiarize the Reciprocating Movements of the Piston

A reciprocating engine uses pistons to convert chemical energy into mechanical motion. It does this by burning a fuel and then directing the hot gas so that it pushes on a piston. The piston is connected in such a way that it will begin to turn a circular crankshaft; when the piston has reached the end of its stroke, it will return to its original position without bringing the crankshaft back with it. Historically, the most common types of reciprocating engines have been the steam engine and the internal combustion engine. The amount of power a reciprocating engine delivers is linked to the total internal volume of its cylinders. The first example of a reciprocating engine to be in widespread use was the steam engine. By the early 19th century, British engineers developed steam engine designs that provided enough power to compete with water wheels. This power could be used for a variety of purposes far away from rivers—steam engines soon found their way into factories, railroad locomotives and ships and were a driving force behind the First Industrial Revolution.
In these steam engines, coal is burned to supply the heat to boil water. The resulting high-pressure steam is then funneled into a cylinder with a piston in it. The piston is pushed to the end of the cylinder, turning a crankshaft via a connecting rod. At this point, a valve directs the steam away from the cylinder so that it doesn’t act on the piston any longer. Now that the crankshaft is moving, its momentum can drag the piston back to its original position, and the cycle can start all over again. 
Another type of reciprocating engine is the internal combustion engine. An internal combustion engine gets its heat from a chemical fuel, such as gasoline, that is burned inside its cylinders. Intake valves allow air to flow in before the fuel is combusted. Likewise, exhaust valves allow gases to exit the engine after combustion has taken place. Carburetors or, increasingly, fuel injectors, permit the proper mixture of fuel and air for ideal combustion. 
In an internal combustion engine, pistons are mechanically connected to a crankshaft—if one piston moves, all other pistons must move with it. Their positions, however, are staggered so that while one piston is undergoing combustion, another may be exhausting gases. This configuration leads to a less jerky reciprocating engine, because power is being produced at more than one part of the full cycle. In automobiles, internal combustion engines commonly have between four and eight cylinders. 

How to Inspect or How to Replace Cylinder Head Gasket

You can use a Compression Tester. And inspect the engine to know or to determined if there's a defect of  Head Gasket or a Piston Ring.
You can conduct it by the standard procedures
First conduct it with compression tester for DRY method Standard psi is 142 for the minimum and have the maximum of 179 psi. Second is to conduct a WET  method.
Before embarking upon the procedure, the battery of the car should be disconnected. Not doing so could cause a spark, resulting in a possible electric shock to the mechanic. Remove the timing chain casing, and mark the timing position of the gears. To do this, use a paint marker, and mark a small spot where each timing notch is located. This ensures their correct alignment during reassembly, and prevents the mechanic from having to retime the engine following the correction of the blown head gasket.
Remove the timing chain, followed by the tappet cover. The next step will depend on the engine type. With a six-cylinder or an eight-cylinder engine, a removal of the intake manifold is needed, followed by the removal of the head bolts. In a four-cylinder engine, which is a single head engine, this step can be skipped. Completely lift the head off the engine block, and remove and discard the blown head gasket.
Check to see if the block itself is level. Use a straight-edged ruler to see if any gaps are present between ruler and the engine block. If any are present, the block is warped and needs to be leveled out. Repeat the process with the head. If no gaps are present between the ruler and the head, it is safe to reassemble the engine using a new head gasket.
Put the gasket upon the engine block. Place the head back on the engine. In a crisscross pattern, working from the center out, use a torque wrench to tighten the head bolts to the proper torque level required by the vehicle. A user manual will be required to determine the proper amount of torque for this step.   
Proceed with reinstalling the intake manifold. Replace the tappet cover, timing chain, and timing chain casing. Drain and change the vehicle's oil. This will need to be done to eliminate any moisture in the oil caused by a possible antifreeze leak, which can result in the occurrence of a blown head gasket.  
Change the antifreeze as well. This will allow it to cool better, preventing the engine from overheating once again. Hook the battery up, and the procedure is complete. 

Standards Maintenance of Tires

Many drivers fail to realize the importance of the tires they drive on, and are surprised when the tires fail or require replacement. In fact, proper maintenance of car tires is crucial to vehicle safety and the long life of a car, and when done properly, extends the life of the tires as well. There are a few basic steps to tire maintenance, and important precautions which all drivers should follow to improve the life of their tires, along with personal safety. There is no hard and fast rule of thumb on how long tires will last, primarily because this greatly depends on how the car is driven, where it is driven, and how well the tires are maintained. Generally under optimum circumstances, drivers should replace their tires every four to five years. The first step in tire maintenance is selecting the right tires. Always use the type of tire recommended for your vehicle. This information is usually listed in the owner's manual and inside the door. If you are unsure, check with a mechanic to be sure that you are purchasing the right tire. Once your tires have been installed, you are responsible for keeping them in good shape by checking their inflation frequently and periodically rotating them.  
Keeping your tires inflated to the correct pressure is very important. Many drivers check the inflation of their tires every time they get fuel, which is an excellent idea because if the tires are low, the gas station provides compressed air for inflation. All vehicles have a recommended inflation level listed inside the door, and all tires have an inflation rating which you should check as well. The recommended inflation is based on the load limit rating for your car, and it is important to make sure that your car's recommended load limit is not exceeded as well.  
Additionally, you should make sure that your car is properly aligned, having the alignment checked when you change the oil and after an accident of any size. A car that is out of alignment will wear tires unevenly, ultimately causing damage. The wheels may also need to be balanced, especially if you notice shuddering or jimmying at high rates of speed. 
Additionally, drivers should be cautious about the surfaces they drive on and reckless driving. In addition to being dangerous, reckless driving is very demanding on automobile tires and will lead to a need for replacement. Hot roads, heavily pockmarked or potholed roads, and roads undergoing resurfacing will cause your car's alignment to slip, as well as causing damage to the tires. If you drive in difficult conditions frequently, you should have the alignment checked frequently as well, and correct the alignment if necessary. In some areas, drivers align their cars two or more times a year due to bad roads.   
Bad shock absorbers and struts can affect tire wear. By maintaining correct tire pressure and alignment, as well as checking on the mechanical features of your car, the tires are likely to last longer and keep you safer. If you drive more safely and conscientiously, you will also have longer lived tires, as well as maintaining a safe vehicle for you and your family. 
  

Emissions Causes and How to Fix it

Engine emissions are gases and particulates that are expelled by a motor or other mechanical device. Particulates are small dust particles. Internal combustion engines, like the ones used in vehicles, emit emissions from the engine exhaust, the fuel tank, and the motor itself. Automobile exhaust is composed of carbon dioxide, carbon monoxide, methane, and formaldehyde. The exhaust also contains particulates and water vapor.

Engines also produce hydrocarbons when fuel is not consumed efficiently. Hydrocarbons are compounds that are made of carbon and hydrogen. Methane is a hydrocarbon and is a greenhouse gas that contributes to the greenhouse effect.
Greenhouse gases, like methane, accumulate in Earth’s atmosphere and become a barrier that traps heat close to the planet’s surface; this is the greenhouse effect. Hydrocarbons are also thought to contribute to global warming. Global warming is the alteration of a planet’s temperature, which affects weather patterns, climates, crops, and disease. Vehicles are now being manufactured with the reduction of carbon engine emissions in mind.
The fuel tank and the carburetor are insulated to limit the amount of fuel vapor that they exude. The carburetor is a device that supplies the engine with a blend of air and fuel. When the engine is not in use, fuel vapors flow into a canister which contains activated charcoal. The charcoal absorbs the fuel vapors. These vapors are then expelled into the combustion chamber and destroyed when the engine is started. 
Vehicle engine emissions are controlled in three ways. The first controls and limits the amount of fuel in the mixture injected by the carburetor. This ensures that more fuel is thoroughly consumed, because this helps reduce the amount of byproducts produced, and the resulting emissions. The second method of engine control allows hydrocarbons to flow back into the engine to be further consumed by the combustion process. Finally, the catalytic converter gives the hydrocarbons and particulates an additional area to be consumed and destroyed.
The catalytic converter helps to reduce the emissions of hydrocarbons, carbon monoxide, and nitrogen oxides. The Environmental Protection Agency (EPA) in the U.S. is invested with the authority to regulate engine emissions, as well as to monitor the air quality in general. The EPA issued a federal regulation that required all car manufacturers to equip automobiles with catalytic converters, and by doing so, reduced the emissions of unburned hydrocarbons by 85%.  
In the U.S., the Clean Air Act Amendment of 1990 has helped to effectively reduce engine emissions. Large engines and automobiles are burning fuels more efficiently, and their contributions to air pollution have been greatly reduced. Smaller engines are also being improved and their fuel efficiency increased. Therefore, those contributions to pollution have also been decreased. 
 

Parts of Hydraulic Brakes

As motorized vehicles became more powerful, the need for more powerful brakes became important to the design of any automobile, motorcycle, or truck. Perhaps the most commonly used braking system that takes on this demand is the hydraulic brake, which uses a master cylinder, line, and caliper filled with liquid to actuate pistons that press brake pads against a moving rotor or drum. Hydraulic brake systems can be found on most automobiles and motorcycles on the road today, as well as on some bicycles. 
There are several main components to the hydraulic brake. The master cylinder is the piece closest to the operator of the vehicle which contains a brake pedal or lever that pushes a piston rod into the cylinder. The airtight master cylinder then allows the liquid to be pushed into a hydraulic line or hose. These lines and hoses can be flexible or rigid, depending on the application, but almost all lines and hoses are designed to allow for minimum flexibility, which would allow the fluid inside the line to expand outward rather than directionally toward the caliper. 
The caliper of the hydraulic brake can work in a few ways. On hydraulic brake systems that use a disk, the caliper is a metal housing that rests on either side of a rotor. The hydraulic line connects the master cylinder to the caliper, and as fluid is pushed through the line and into the caliper, a set of pistons are actuated inside the caliper. These pistons push inward toward the rotor. In between the pistons and the rotor sit the brake pads, which can be made of asbestos or other composite materials that are resistant to heat and brake fade. 
Another type of caliper is used on hydraulic drum brakes. Instead of being mounted on the outside of a rotor, this caliper — called a wheel cylinder — is instead mounted inside a metal drum. The pistons push outward instead of inward to press the brake pads against the inside of the drum, rather than the outside of a disk. 
The type of fluid used in the hydraulic brake system depends on its application. For most cars, trucks and motorcycles, DOT 4 or DOT 5 brake fluid is used. This type of fluid is glycol-ether based and is particularly resistant to heat. On some hydraulic brakes, mineral oils can be used instead, but the two fluids are not interchangeable on brake systems and should only be used on brakes designed for that particular fluid. Any hydraulic brake system must be periodically bled to ensure no air is in the lines, which may cause power loss.

Disk Brake Parts and Functions

Though many systems for slowing down a wheel on a vehicle have been designed and implemented over the course of more than a century, no design is more prevalent today than the disk brake. A disk brake system uses a rotor, usually made of composite materials such as iron, ceramic, carbon, and Kevlar®, that is fixed to a wheel and slowed using a caliper that forces brake pads to contact the disk from both sides simultaneously. Disk brake systems are used extensively on automobiles, motorcycles, bicycles, and other gas-powered and human-powered vehicles.

Disk brakes were developed as early as the late nineteenth century, but design flaws kept disk brake systems from entering mainstream use. The most difficult problem to overcome was heat transfer, or the disk's inability to distribute friction heat effectively. This problem was called brake fade and was quite prevalent on early models of disk brakes. Further, because roads around that time were primitive and unpaved, dirt and dust often came in contact with the disk brake system, reducing the power and effectiveness of the brake and often leading to premature wear of the individual components. 
These problems were eventually solved by using composite materials that distributed heat more effectively and were less susceptible to quick wear. Other methods of solving the heat and dirt problems included drilling holes in the rotor itself, which allowed heat to disperse more effectively and dirt and grit to pass through without affecting the performance of the brake to a great degree.
In order to actuate the brake pads and make them press against the rotor with significant strength to slow the wheel, several methods have been developed. Cable actuated levers are common on bicycles, where massive amounts of force are not needed to slow the vehicle. On automobiles, motorcycles, and even many bicycles, hydraulic systems are employed to transfer power from the brake lever or pedal to the brake caliper. These hydraulic disk brake systems use a viscous liquid, usually an oil or other thick fluid, contained in lines rigid enough to contain the force of the moving liquid. When the brake lever or pedal is actuated, the oil or fluid is forced into the brake caliper, which in turn uses a series of pistons to thrust the pads against the rotor. Other systems of actuation include pneumatic systems and electromagnetic systems, both of which tend to be more complex but just as effective.
 

Jävla skitsystem!

Pardon the Swedish!

The heading is actually the title of a Swedish book about how people can be stressed in a digital working environment. I think this is one of the most important books written about IT-systems and the problems they can bring on a personal level for the people who are forced to using them. Too bad is is not translated to English (yet?).
It is not a technical book, the primary audience are people using IT systems, secondly it is targeted at people planning and buying IT systems. It systematically lists 8 major stress factors and what can be done about them. Not all are caused by ignorant developers...
I think it is very valuable to read for people developing systems, so much I would make it mandatory reading for students in software engineering, if only it was published in English. There is some information in English, including a short slide presentation.

You can buy the book directly at the website or at major Swedish online bookstores.

You tend to favour the solutions you are familliar with...

When I talk to students about the role of the architect I always make a point of the architect must know when not to use a particular solution/pattern/style (the old "Kill your darlings"). Regardless of this I have seen examples when an entire class thinks that a 3-tier architecture is the best solution in a project because they took a course on databases the previous semester.
Likewise, when I talked about component-based architectures in a lecture and gave examples based on AUTOSAR, a lot of students thought that components was the thing, even if it complicated the solution for the developers and the benefits with components was not really relevant in the student  project.

This is not surprising since I am talking about students with limited experience to various problems encountered when developing real systems. But I also think this is a problem for professional developers as well, including myself. We tend to stick to what we know and don't reflect if what we know actually makes things worse than better.

How to Disassemble the Hydraulics Brake Assembly

Brake Assembly Parts

Brake Assembly This is the brake assembly we have their the Brake shoe, The adjusting Lever, Parking Brake Cable, Wheel/Cylinder Assembly, Primary Shoe Return Spring/Return Spring, Adjusting Screw, Screw Adjsuter, Anchor Spring/Adjusting Spring. Each of the parts have their own functions.Brake Shoe - the function of the brake shoe is to contact and to grip from his position to the brake drum.Adjusting Lever - is to adjust the measurement between brake shoe to the brake drum. This also called as the "Manual Adjuster".Parking Brake Cable - this is the secondary connection of the brake. Which is commonly called as the "Hand Brake". This is also used to adjust the measurement between the brake shoe to the brake drum. This is also called as the "Easy Access Adjusting". Because you can adjust by not getting the tire.
Wheel/Cylinder Assembly - this would act as the connection from brake fluid to push the brake shoe to grip the brake. Cylinder Assembly have 2 parts inside of them. Which is the Piston and the Spring. Pistons act as the pusher from the pressure of the brake fluid and he will push the brake shoe to contact the brake drum. Which is cause for the brake.Return Spring - is used to adjust and to hold the adjuster lever. Which is commonly known as the return spring because this is act also as the holder of the adjuster lever.Adjusting Screw - is used to adjust from inner to outer. When the brake shoe comes thick and need to adjust by turning it. So that it will have good contact between brake shoe and the brake drum.Adjuster Screw - is used to hold the brake shoe to avoid causing disengagement from the brake. This also an very important things. Just to support the brake shoe by arcing.Anchor Spring - this is the secondary spring which is holding the brake shoe apart.To familiarize on how to assemble the Brake Assembly just refer to the image above.

Familiarize CNG

Compressed natural gas (CNG) is natural gas which has been compressed to around one percent of its original volume so that it can be used as a fuel source to power a vehicle. This alternative fuel is used in many regions of the world to power both dedicated vehicles which run on natural gas only and bi-fuel vehicles which run on natural gas and another fuel. Several auto manufacturers make natural gas vehicles or can do so by request, and companies which manufacture buses and other vehicles for commercial use often offer a compressed natural gas option.
This fuel consists mostly of methane, and can be harvested in a number of different ways. It is pumped into tanks which hold it in compression until it is needed. One of the biggest advantages to compressed natural gas is that it is cleaner burning than most other fuels, producing far fewer pollutants. It is also nontoxic and noncorrosive, and poses a low safety risk because it dissipates quickly in the event of a spill.
While this fuel can be flammable, it is only flammable under certain conditions. Usually it dissipates too quickly to be explosive, reducing safety risk for people who work with natural gas vehicles and for first responders who might be called upon to respond to accident with a CNG vehicle. The holding tanks are usually carefully structured and designed to make spills highly unlikely. CNG is also less hard on engines, reducing the amount of maintenance needed to keep a vehicle functioning well.
There are some disadvantages to using compressed natural gas as a fuel source. Energywise, vehicles cannot go as far on a single tank of CNG as they can on a tank of gasoline or diesel. As a result, this means that some vehicles may have added tanks to meet their energy needs, which adds to the weight of the vehicle, cutting down on efficiency. The extra tanks can also reduce the amount of room available in the vehicle.
This fuel can also be hard to obtain in some areas. If people have to drive a long distance to fuel up, the energy and environmental savings of compressed natural gas may not balance out. Difficulties with obtaining fuel can also be a problem for people on trips, as they may need to map out a route which ensures that they pass by stations which allow CNG refueling and this can put limitations on a trip.
   

How to inspect Clutch Disengaging and Problem

Parts and Construction of The Clutch System

Clutch Cover - Purpose of clutch cover to engage and disengaged the engine power accurately and quickly.

Drive Train Construction and Flow

ENGINE ->CLUTCH ->TRANSMISSION->PROPELLER SHAFT->DIFFERENTIAL->WHEEL

Clutch Cover Component Parts

Pivot Ring
Diaphragm Spring
Retracting Spring
Pressure Plate
Clutch Disk or Lining

Clutch Disk Component Parts

Clutch Lining
Airway
Torsion Damper
Revets


How to inspect clutch disengaging problem.First check the pedal free play if it is standard or not.standard measurement of free play is 2in - 3in. Thats give allowance to depressed for not an early disengaging. Check Pedal Height. From the floor of your car to the clutch pedal rubber. Standard measurement is 145mm - 150mm. If it is 145mm above is the height of your clutch pedal. That would be nice. Check for air in clutch line (for hydrolics only) Clutch master cylinder and his primary and secondary. This is to avoid slide of your clutch. This is also inspect the pressure of your clutch line. Check also the compression or diaphragm spring. Check the Disk or Lining.

Clutch Slips.First inspect the clutch facing which is the clutch cover, pressure spring. Check if it is not oily, worn or burn out. If that would have just replace your clutch cover. Next is to check also the compression or diaphragm spring if it is ok. If not Replace it.

Clutch Grabs. First Check clutch disk if it is not oily, broken torsion damper, loosen rivets. And also check the diaphragm spring.

Clutch Noise. Check the rotating and Sliding parts.if it is okey. Then check the release bearing then check also the pilot bearing and the clutch fork.

Basic Information of Lamp Indicator

An indicator lamp is a warning device used to alert drivers of potential problems with their vehicles. Functions such as oil pressure, water temperature and the voltage are all typically wired into dashboard indicator lamps. When there is a potential problem or a dangerous reading from a engine sensor, the indicator lamp will illuminate. Many vehicles have both full-functioning gauges that show the reading of the function as well as an indicator lamp. Typically, lower-optioned and base-packaged vehicles will possess only the indicator lamp system.
For every function of the automobile engine, a sensor exists to transmit readings back to the dashboard. This system of warning lights and function indicators allows the driver to have an understanding of how the engine is operating. The sensors are programed to send a signal to the indicator lamp in the case of a non-standard sensor reading. When this signal is sent, the warning light illuminates, telling the driver there is a problem. The situation can then be assessed, and the driver can determine if immediate service is warranted or if the vehicle can continue on and be serviced later.Although rare, an occasional faulty sensor can trigger a reaction from a warning lamp. When this happens, it can typically only be detected through testing of the sensor itself. While a mechanical gauge is triggered by the actual component being measured, such as water temperature or oil pressure, the indicator lamp uses electrical senders that measure the function against a go, no-go parameter engineered into the sensor. This type of system is not as accurate as the mechanical gauge, though it is more easily understood by the average driver.
Many automobile operators have no idea what their proper engine oil pressure or temperature should be before it is considered overheating. Most drivers, on the other hand, do understand that a problem exists when a warning light is illuminated on the vehicle's dashboard. The indicator lamp typically has the engine's function displayed inside the illuminated light—when the lamp marked "Temp." is illuminated, the driver understands that the vehicle's temperature is presenting a problem. When developing the warning system, it was understood that a driver must posses some mechanical ability or knowledge to decipher the readings of the mechanical gauges. Designers reasoned, however, that everyone could understand that there was a problem with the vehicle if a bright red light suddenly came on within the dashboard.  

Basic Information of the Chassis

A chassis is the part of an automobile that the suspension mounts to. Most vehicles manufactured since the 1970s use a uni-body construction method. In this type of design, the chassis is not separate from the body, as it is in a vehicle that uses a separate frame. With uni-body vehicles, the chassis is attached to reinforced sheet metal mounting points designed into the body of the vehicle. Some vehicles, such as pick-up trucks and heavy-duty vehicles, continue to use a separate frame and the chassis, for these types of vehicles mounts directly to the frame.
For the most part, the chassis of a vehicle can be identified as any component that moves—other than the body—when the vehicle is bounced. Springs, struts and A-frames are all chassis components on a vehicle. Other well-known chassis pieces are control arms, sway bars and axle assemblies. Lesser-know chassis components such as drag links, tie rods and ball joints are very important to the handling of the vehicle. These lesser known components are often neglected when a vehicle undergoes servicing.Most suspension pieces utilize a grease Zerk that allows the part to be serviced and lubricated. A few pumps from a grease gun will properly lubricate a suspension component and keep it in peak operational order. The proper time to perform suspension maintenance on most vehicles is at designated oil change intervals. Some newly-manufactured suspension components come without grease fittings. These components are self-contained and require replacement in the case of part failure since no preventative maintenance can be practiced without grease fittings. 
When replacing a suspension component, vehicle owners should opt to use the most high-performance part available. Many vehicles are offered in different option levels or performance packages. The high-performance packages used much better suspension pieces for most of the system components. By replacing standard package parts with high-performance parts, the vehicle's ride and handling will be drastically improved.
It is often necessary to replace multiple components when upgrading any suspension item. Components such as sway bar bushings are much stiffer if purchased for a performance suspension package; however, they are also designed to fit a much larger diameter sway bar. In a situation such as this, upgrading to a stiffer sway arm bushing would require also upgrading the sway arm and the sway arm mounts as well as the mounting bolts. The result, however, will be a better-handling vehicle chassis when negotiating tight corners. 

Basic Information of the Cylinder Head

Internal combustion engines typically include a cylinder block, which houses the pistons and the cylinders through which they move, and a cylinder head to cap off the block. Certain engine configurations have multiple cylinder heads, each of which sits upon its own bank of cylinders. In some engines, such as the flathead type, the cylinder head can be very simple and designed solely to provide a sealed, removable top-end for the head. Other engines have either part of valve train, or both the valve train and the camp shaft, within the head. In either case, the cylinder head is generally mounted to the block with a graphite or metal head gasket, effectively turning the cylinders into sealed combustion chambers.
Simple engines, such as those used in lawnmowers and inline engines — like L4 and L6 units, have a single cylinder head to seal up all of the combustion chambers. Other common engines, such as the V6 and V8, contain two parallel banks of cylinders. This requires two cylinder heads, mounted in such a way to form the appearance of a V, in order to seal the cylinder block. Another type of engine that uses two cylinder heads is the flat, or boxer, engine. This configuration is similar to the V-formation in that both banks of cylinders are driven off a single crankshaft, though, in the case of the flat engine, the banks are aligned on the same horizontal plane.
The complexity of a cylinder head depends largely on the type of engine it is used in. Many older automobiles utilized what is known as a flathead engine. As the name implies, these engines used a head that was a simple, flat panel, mounted via the head gasket, to a cylinder block that itself contained the entire valve train. Cylinder heads in these applications still performed the vital function of sealing the combustion chambers, though they lacked much of the functionality found in more modern units.
Modern cylinder heads are typically used in overhead valve (OHV) or overhead cam (OHC) configurations. A cylinder head in an OHV engine generally contains valve train components, such as pushrods, poppet valves and other components that are operated by a camshaft located in the cylinder block. By contrast, OHC engines have the camshaft itself in the head, making for an even more complex unit. These types of cylinder heads usually contain the entire valve train.

Basic Discussion of Flywheel

Flywheel energy storage is a method for storing energy using a rapidly spinning flywheel. The flywheel, which generally spins in a vacuum, stores energy as rotational energy. Energy can be removed from the system or added to the system by means of an electric motor/generator. Flywheels spin at a very high number of revolutions per minute (RPM) and can store a significant amount of energy. The durable nature of flywheel energy storage systems and their ability to rapidly absorb or discharge large amounts of energy make them excellent candidates to replace or supplement conventional batteries for use in electric vehicles.
Older flywheel energy storage systems relied on purely mechanical bearings to support a rapidly rotating flywheel. Modern versions instead use magnetic bearings. As a result, they are more durable, because the moving parts inside the system are not subject to constant friction. Some modern flywheel systems even employ superconducting magnets, although the cost and temperature requirements for these systems limit their usefulness.
The reduced friction of magnetic bearings also increases the utility of flywheels in storing energy. This is because less kinetic energy is lost to friction while the flywheel is spinning. The increased storage efficiency is particularly important when a flywheel is used to store energy for longer periods of time, because mechanical flywheel systems will dissipate much of their mechanical energy over the first hour after charging.
Flywheels are used in many applications where rapid charging and discharging are important. This type of energy storage has been used successfully to power motor vehicles and works especially well as a form of regenerative braking. The fact that flywheels act as large gyroscopes when they are spinning requires special engineering so that the handling of vehicles is not adversely impacted, and it can serve to stabilize vehicles.
Flywheel batteries have been suggested as a means to power next-generation weapon systems. They have the ability to store more energy than conventional batteries and to discharge that energy faster. This led the United States Army to consider using flywheels to power weapons using electromagnets driven by flywheels.
The largest problem with flywheel energy storage is the potential for damage and injury if a charged flywheel is broken. These systems store energy as kinetic, rotational energy, so serious damage to the flywheel housing can cause the flywheel to shatter. Charged flywheels typically spin at 40,000-60,000 RPM, so this can release dangerous shrapnel. Modern flywheel systems employ advanced flywheel housings to limit the danger from this sort of event.

Basic Discussion of the Break Lining

A brake lining is a friction material bonded to the steel brake shoes or pads. In most automotive brake pads and shoes, the brake lining is riveted to the metal pad or shoe. As the brake lining wears down, the brakes may chatter, squeak or squeal. Left unattended, the brake lining will continue to wear until the rivets begin to eat into the rotor or drum and generate the need for a costly brake repair. Brake pads and shoes are typically replaced as a unit, unlike earlier brake jobs that required a new brake lining be applied to a vehicle's brake pads.
When deciding on new brake components for a vehicle, there are often many choices for the type of brake lining used. As a rule, the brake lining that includes a lifetime warranty is a very hard friction material. This material is intended to wear for a long time, requiring less frequent brake changes. The downside is that this very abrasive substance is prone to wearing out brake rotors and brake shoes at a much faster rate than the original type brakes. When choosing a lifetime brake pad, it is wise to reference the vehicle manufacturer's recommendation.

When it is time to change brake pads on any vehicle, it is always important to change both sides of an axle at the same time. Although it may be tempting to only change the noisy side, an uneven braking surface can cause an ill-handling vehicle under braking conditions. Changing both the left and right side brake pads ensures even braking pressure when the brake pedal is depressed. This is not always felt in normal day-to-day driving; under emergency braking conditions, however, it can mean the difference in successfully stopping a vehicle or being involved in a skid.

While the earliest brake lining was made with asbestos and other dangerous materials, brake linings manufactured since 1970 have not used asbestos-containing materials. Advances in brake lining technology have created longer lasting, better stopping braking components. Using space-age technology, a brake pad will often last two years or more depending on driving habits. A new brake pad should never be installed on an old rotor or drum. It is always wise to resurface the rotors and shoes when changing pads.
Surfacing the rotors and shoes ensures a fresh and smooth surface for the pads to grab onto. It also creates a level surface so the pads wear evenly. If the rotor or drum has been worn too thin, it should be replaced to ensure safety.

Proper Conducting of Engine Timing

Ignition timing is the relation of spark to the position of an internal combustion engine's pistons. Measured in degrees of the piston's stroke within the cylinder wall, ignition timing is relative to the before or advanced relation of the piston to the top dead center of its stroke, or the after or retarded position. The position of the piston in relation to the spark plug igniting the air fuel mixture, which is ignition timing, dictates an engine's power output as well as its effectiveness in burning the fuel. A vehicle's fuel mileage, peak power and engine longevity are all dependent upon the ignition timing in relation to the 360 degrees of the spinning crankshaft.In a four-stroke engine with an intake, compression, ignition and exhaust stroke, the crankshaft brings the piston to its absolute highest position within the cylinder two times in one cycle. As the piston approaches the top of the compression stroke, ignition timing dictates when the spark plug will fire. If the mixture is fired too early, the piston will fight rising completely to the top of the stroke. If the ignition timing fires the spark too late, the power is lost, as the piston is already on its way down the stroke.
The effectiveness of ignition timing can best be compared to pushing a person on a swing. If the swing is grasped early and then followed up and pushed down violently, the swing will go up with great force. If the same swing is only contacted by the pusher as it is heading away, the person on the swing will hardly notice the power of the push. The same holds true for a piston within an engine; the ignition timing must occur at precisely the right point in the piston's travels in order to provide the maximum power.
With the engine running, timing is set by using a timing light and taking a reading from the engine's harmonic balancer. The balancer is attached to the crankshaft and is marked with lines and numbered in degrees both before and after top dead center of the piston in its stroke. Typically, 1970s and earlier engines are tuned before top dead center and post 1980s vehicles are timed after top dead center. This is in response to the manufacturers' attempts at tuning vehicles down to conserve gasoline. These so-called "smog engines" were conservatively tuned in an attempt at providing better fuel mileage, with some manufacturers going as far as relocating the position of the balancer on the crankshaft several degrees in the retarded position to enhance the reading.

Functions and Replacing Ignition Parts

In order to replace an ignition, it is imperative that all components be examined. Failure to inspect every piece of the system can lead to a non-starting vehicle even after replacing the ignition. Spark plugs, spark plug wires, distributor caps and rotors in vehicles so-equipped as well as points and any condensers found on the distributor should also be changed when it's time to replace an ignition. In vehicles equipped with an electronic ignition, it is important to change the ignition module as well when making the effort to replace an ignition system.
The ignition in a vehicle is comprised of several components. When replacing any one piece of the system, it is wise to examine the rest of the system for signs of wear. Any change in components can lead to a break down in the other components. Changing spark plugs can lead to a discovery that the spark plug wires should have been changed. This is why it is wise to replace an ignition as a complete system.Most U.S. vehicles produced after 1995 do not require tune-ups prior to the vehicle reaching 25,000 miles. Advances in spark plug manufacture do not require a vehicle owner to replace an ignition as frequently as many owners believe the process is needed. Engine efficiency and better fuel and oils have advanced to the point that vehicle engine components do not require servicing as frequently. This includes engine oil changes, which are now recommended no more than every six months or 5,000 miles by many manufacturers
In order to save on future repair work, it is wise to check the serpentine belt system on the vehicle's engine when planning to replace an ignition. If signs of wear exist in the form of cracking or fraying along the edges of the belt, it should be replaced when the vehicle is scheduled to have its ignition replaced. This saves time, as many of the components that require removal to service the belts are also removed to replace an ignition. This also cuts the labor in half since the parts will be removed in either case.  
A vehicle also should be tuned after its ignition components have been changed. Often, the vehicle's spark timing can be altered by manipulating the spark plug wires and distributor cap. This is not as prevalent on distributor-less ignition systems. It is, however, always recommended that the vehicle be driven cautiously for the first 50 to 100 miles following a vehicle owner's decision to replace an ignition system. This allows the system to be examined for any loose components following the service.

Functions of Electric Transmission Control Unit

A transmission control unit or TCU is an electronic device used on automatic vehicle transmissions to control the manner in which they work. Sensors within the transmission and on the engine work in conjunction with the transmission control unit to change gears, lock the torque converter and monitor the true speed of the vehicle. In most vehicles, the transmission control unit works in conjunction with the vehicle's on-board computer to adjust engine timing, fuel flow and a variety of other critical vehicle functions. By monitoring the transmission functions, the transmission control unit is able to assist the vehicle's operator in saving fuel, getting the most performance out of the vehicle and even controlling the vehicle better in poor driving conditions.
The first automatic transmissions were completely dependent on hydraulic power to provide shifting points. Torque converters often slipped and cost the operator money in the form of wasted fuel mileage and efficiency. Beginning in the mid-1980s, vehicle manufacturers began experimenting with electronically-controlled transmissions. The original goal of the transmission control unit was to increase fuel mileage in vehicles by eliminating waste. The result offered much more than was originally conceived.

In order to choose a gear that offers the best results for the vehicle, sensors mounted on the wheels, engine crankshaft and the transmission output shaft are all sending information to the transmission control unit. By monitoring this information, the transmission control unit is able to choose the proper gearing to provide the optimal results for the operator. Functions such as throttle position and engine temperature are all sent to the transmission control unit from the engine control module, or ECM, and the vehicle requirements are evaluated by the vehicle's computer systems.
While best known for controlling the transmission's functions while driving, the transmission control unit is also used as a safety device on many vehicles. Wired into the brake light switch, the TCU prevents the vehicle from being placed into a gear unless the brake pedal is being depressed. This feature is especially important for vehicles owned by families with small children. Even with the engine running, a small child is unable to accidentally move the shifter and place the vehicle in gear while standing or sitting in the front seat of the vehicle. The TCU is also programmed to deactivate the cruise control in the event that the transmission is accidentally knocked into neutral, preventing the engine from excessive revving and potential damage.