Automobile generally consists of four basic parts: engine, chassis, body and electrical equipment.
Automotive Engine: Engine is the power device of automobile. It consists of two major mechanisms and five major systems: crank-connecting rod mechanism; valve distribution mechanism; fuel supply system; cooling system; lubrication system; ignition system; starting system.
1. Cooling system: generally composed of water tank, water pump, radiator, fan, thermostat, water thermometer and water discharge switch. The automobile engine adopts two kinds of cooling methods, namely air cooling and water cooling. Generally, water cooling is used in automobile engines.
2. Lubrication system: Engine lubrication system consists of oil pump, filter, oil filter, oil channel, pressure limiting valve, oil meter, pressure sensing plug and oil ruler.
3. Fuel system: The fuel system of gasoline engine consists of gasoline tank, gasoline meter, gasoline pipe, gasoline filter, gasoline pump, carburetor, air filter, intake and exhaust manifold, etc.
Chassis of automobile: The function of chassis is to support and install the automobile engine and its components and assemblies, form the overall shape of the automobile, and accept the power of the engine, so that the automobile can generate movement and ensure normal driving. Chassis is composed of four parts: transmission system, driving system, steering system and braking system.
1. Driving system: The power from the automobile engine is transmitted to the driving wheel by the driving system. The transmission system has the functions of deceleration, speed change, backing up, interruption power, wheel-to-wheel differential and shaft differential. Working with the engine, it can ensure the normal running of the vehicle under various working conditions, and has good power and economy. It is mainly composed of clutch, transmission, universal joint, transmission shaft and drive axle.
Clutch: Its function is to make the engine power and transmission device smoothly engage or temporarily separate, so as to facilitate the driver to start, stop, shift and other operations of the car.
Transmission: It is composed of transmission housing, transmission cover, first shaft, second shaft, intermediate shaft, reverse shaft, gear, bearing, control mechanism, etc. It is used for automobile speed change and variable output torque.
2. Driving system: It consists of frame, axle, suspension and wheel. The functions of the driving system are:
A. Accept the power of the transmission system and generate traction force through the action of driving wheel and road surface to make the vehicle run normally.
B. Bearing the total weight of the car and the reaction of the ground;
C. Relax the impact of uneven road surface on the car body, attenuate the vibration during driving, and maintain the ride smoothness;
D. Cooperate with steering system to ensure vehicle handling stability.
3. Steering system: The special mechanism used to change or restore the direction of the vehicle is called automobile steering system. Basic Composition of Steering System
A. The steering control mechanism is mainly composed of steering wheel, steering axle, steering string, etc.
B. The steering gear transforms the rotation of the steering wheel into the swing of the steering rocker arm or the linear reciprocating motion of the rack shaft, and enlarges the steering control force. The bogie is usually fixed on the frame or body of the car, and the steering control force will change the transmission direction after passing through the bogie.
C. The steering transmission mechanism transmits the output force and motion of the steering gear to the wheel (steering knuckle) and makes the left and right wheels deflect according to a certain relationship.
4. Braking system: A series of special devices on automobiles are collectively called braking system, which are used to exert certain forces on certain parts of automobiles (mainly wheels). Its functions are: to make the driving car decelerate or even stop forcibly according to the driver's requirements; to make the parked car stop steadily under various road conditions (including on the ramp); to keep the speed of the downhill vehicle stable.
Brake system classification:
A. The function of press brake system
Braking system can be divided into driving braking system, parking braking system, emergency braking system and auxiliary braking system. The braking system used to slow down or even stop a moving car is called the driving braking system; the braking system used to keep the parked car in place is called the parking braking system; the braking system used to ensure that the car can still slow down or stop when the braking system fails is called the emergency braking system; in the process of driving, the auxiliary driving braking system is called the emergency braking system. The braking system that reduces the speed or keeps the speed stable can not be called auxiliary braking system. In the above braking systems, the driving brake system and the parking brake system are necessary for every vehicle.
B. Manipulating energy by braking
Braking system can be divided into manpower braking system, power braking system and servo braking system. The braking system with the driver's body as the sole braking energy is called the manpower braking system; the braking system with the pneumatic or hydraulic potential energy converted from the engine's power is called the power braking system; the braking system with both manpower and engine power is called the servo braking system or the assistant braking system.
C. The transmission mode of braking energy
Braking system can be divided into mechanical, hydraulic, pneumatic, electromagnetic and so on. At the same time, the brake system with two or more energy transfer modes is called the combined brake system.
Brake system is generally composed of two main parts: brake control mechanism and brake.
A. Brake control mechanism
It generates braking action, controls braking effect and transfers braking energy to all parts of the brake, as well as brake wheel cylinder and brake pipeline.