The Basic Components of an Automobile.

An automobile probably has about 7,000 different parts in it. Some of them make it more comfortable or better looking, but most of them are to make it run.

The three basic components of the automobile are the engine, chassis and body (see Fig.1)

The engine converts the fuel energy into mechanical power. An internal combustion engine powers our modern automolile. The engine burns its fuel within the engine proper, as compared to a steam engine where the fuel is burned externally. The gasoline and air mixture of the internal combustion engine is compressed by a piston inside an airtight cylinder and ignited by a spark. The trapped airfu-el mixture burns fiercely, causing tremendous heat which expands the trapped gases and pushes the piston down. This is the motive power of the automobile. The automobile engine is essentially a heat engine. It requires fuel to burn, a spark to ignite, lubrication to minimize friction, and a cooling system to dissipate unwanted heat.

The fuel system takes a correctly proportioned mixture of gasoline and air to burn and develop the power needed to push the piston down the cylinder. To store, mix, and deliver this airfuel mixture is the duty of the fuel system.

Fig. 1 Basis components of the automobile.

When the explosive mixture of air and gasoline is compressed tightly, a spark is sent through the mixture, setting it on fire, which results in the heat and expansion used to push the piston down the cylinder. The ignition system furnishes a spark to each spark plug when its cylinder is full of the compressed airfuel mixture.

The lubrication system provides a constant flow of filtered oil to all moving parts of the engine. The system consists of an oil pan to store the oil, a, pump to circulate it, a filter to remove soild abrasive particles, and an oil gauge or light in the driver’s compartment for checking purposes.

The engine dervies its power from burning fuel. Unfortunately, not all of this heat can be used, and, if allowed to remain in the engine, it would soon destroy it. The temperature of the burning air-fuel mixture is about 4, 5000F.com-pare this with the boiling point of water, 212?., and the melting point of iron, 2, 5000F. If this unused heat were not removed, the engine would soon melt.

The coolant of the cooling system picks up the excess combustion heat as it is circulated through the block and heads by a centrifugal-type pump, delivered to the radiator where it is cooled, and then returned to the water pump for recirculation.

The chassis comprises the drive line, running gear (undercarriage) and control mechanisms.

The drive line consists of mechanisms and units which transmit torque from the engine to the drive wheels and change torque and rpmin magnitude and direction. Among these mechanisms and units are the clutch, transmission (gearbox), propeller shaft, and final drive comprising dif-ferential and axle shaft.

The clutch is a friction device used to connect and dis-con-nect a driving force from a driven membe. It is used in conjunct-tion with an engine flywheel to provide smooth engagement and disengagement of the engine and manual transmission. Since an internal combustion engine develops little power or torque at low rpm, it must gain speed before it will move the vehicle. How-ever, if a rapidly rotating en-me is suddenly connected to the drive line of a stationary vehicle, a violent shock will result.

A transmission is a speed and power changing device in-stalled at some point between the engine and driving wheels of the vehicle. It provides a means for changing the ratio between engine rpm and driving wheel rpm to bet meet each particular driving situation. It converts torque in magnitude and the direction, allows the automobile to move forth and back and the engine to be disconnected from the drive line for a longer period of time.

The propeller shaft is used to transmit torque from the trans-mission to the final drive at varying angles. The uni-versal joints serve tc compensate for changes in the line of drive by transmiting power from a driving shaft through an angle to a driven shaft. Most cars use two or three univer-sal joints in the drive line between the transmission and differential.

The final drive changes torque and transmit it from the propeller shaft through the differential to the axle shafts at a constant angle.

The differential is a gear system that transfers power from the drive shaft to the driving axles. It also permits one driving wheel to turn faster than the other to prevent skidding and scufting of tires on turns.

The running gear is the backbone of the automobile; it includes the fram, front and rear axles .springs, shock absorbers, wheels and tires.

The control mechanism consist of the steering system for changing the direction of movement and the brakes for decelerating and stopping the automobile.

The body of the truck comprises a cargo body and a driver’s cab. The fenders, radiator grilie, hood, and mudguards also belong to the body.