1. Automobile engine: The engine is the power device of the automobile. It consists of two mechanisms and five systems: crank-connecting rod mechanism; Valve mechanism; Fuel supply system; Cooling system; Lubrication system; Ignition system; Start the system.
1. cooling system: generally composed of water tank, water pump, radiator, fan, thermostat, water thermometer and drain switch. There are two cooling methods for automobile engines, namely air cooling and water cooling. Generally, automobile engines are mostly water-cooled.
2. Lubrication system: The engine lubrication system consists of oil pump, filter screen, oil filter, oil circuit, pressure limiting valve, oil gauge, pressure sensitive plug and dipstick.
3. Fuel system: The fuel system of a gasoline engine consists of a fuel tank, a gasoline meter, a gasoline pipe, a gasoline filter, a gasoline pump, a carburetor, an air filter and an intake and exhaust manifold.
2. Automobile chassis: The role of the chassis is to support and install the automobile engine, its parts and assemblies, form the overall shape of the automobile, accept the power of the engine to make the automobile move, and ensure normal driving. The chassis consists of four parts: transmission system, running system, steering system and braking system.
1. transmission system: the power generated by the automobile engine is transmitted to the driving wheels through the transmission system. The transmission system has the functions of deceleration, speed change, reversing, power interruption, differential speed between wheels, differential speed between shafts and so on. Working with the engine can ensure the normal running of the car under various working conditions, with 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 power of the engine smoothly engage or temporarily separate from the transmission device, so as to facilitate the driver to start, stop and shift gears.
Transmission: It consists of transmission housing, transmission cover, first shaft, second shaft, intermediate shaft, reverse shaft, gears, bearings, control mechanism and other parts, and is used to change the speed and output torque of the automobile. /z & amp； K 1 w w$ L
2. Drive system: composed of frame, axle, suspension and wheels. The function of the drive system is:
A. Receiving the power of the transmission system, and generating traction through the action of the driving wheel and the road surface, so that the automobile can run normally;
B. bear the total weight of the car and the reaction force of the ground;
C. Relieve the impact of uneven road surface on car body, attenuate the vibration when the car is running, and keep the ride comfort;
D cooperate with the steering system to ensure the handling stability of the vehicle.
3. Steering system: The special mechanism used to change or restore the driving direction of the automobile is called the automobile steering system. Basic composition of steering system
A. Steering control mechanism is mainly composed of steering wheel, steering shaft and steering column.
B. The steering gear is a mechanism that converts the rotation of the steering wheel into the swing of the steering rocker arm or the linear reciprocating motion of the rack shaft to amplify the steering control force. The steering gear is generally fixed on the frame or car body, and the steering control force will generally change the transmission direction after passing through the steering gear.
C. The steering transmission mechanism is a mechanism that transmits the force and motion output by the steering gear to the wheels (steering knuckles) and deflects the left and right wheels according to a certain relationship.
4. Braking system: a series of special devices used to make the outside world (mainly the road surface) exert a certain force on some parts of the car (mainly the wheels), so as to make it brake to a certain extent, collectively referred to as braking system. Its function is: to make the moving car slow down or even stop according to the driver's requirements; Make parking stable under various road conditions (including on ramps); Keep the speed of the car downhill stable.
Brake system classification:
A. according to the function of the braking system
The braking system can be divided into service 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 a service braking system. The braking system used to stop the car is called parking braking system. In the case of failure of the service braking system, the braking system that ensures that the car can still slow down or stop is called emergency braking system; During driving, the auxiliary braking system reduces the vehicle speed or keeps the vehicle speed stable, but the braking system of vehicle emergency braking cannot be called the auxiliary braking system. Among the above braking systems, the service braking system and the parking braking system are necessary for every vehicle.
B. according to the braking operation energy.
The braking system can be divided into hand braking system, dynamic braking system and servo braking system. The braking system with the driver's body as the only braking energy source is called hand braking system; A system that completely relies on engine power to convert into potential energy braking in the form of air pressure or hydraulic pressure is called a dynamic braking system; A braking system that uses both human power and engine power for braking is called a servo braking system or an auxiliary braking system.
C. according to the transmission mode of braking energy
Brake system can be divided into mechanical, hydraulic, pneumatic, electromagnetic and so on. At the same time, the braking system with two energy transfer modes is called combined braking system.
The braking system is generally composed of two main parts: the brake operating mechanism and the brake.
A. brake control mechanism
It produces braking effect, controls braking effect, and transmits braking energy to brakes, brake wheel cylinders and brake pipelines.
B. Brake
A component that generates a force (braking force) that hinders the movement or movement tendency of a vehicle. The commonly used brake in automobile is called friction brake, which generates braking torque by using the friction between the working surface of fixed element and rotating element. It has two structural forms: drum brake and disc brake.
3. Car body: The car body is installed on the frame of the chassis for drivers and passengers to ride or load goods. The body of a car or bus is generally an integral structure, and the body of a truck is generally composed of a cab and a cargo box. .
Automobile body structure mainly includes: body shell (body in white), doors, windows, front sheet metal parts, interior and exterior decorative parts and body accessories, seats, ventilation, heating, air conditioning and so on. Trucks and special vehicles also include trucks and other equipment.
1. Body shell (body-in-white) is the installation foundation of all body parts, which usually refers to a rigid spatial structure composed of main load-bearing elements such as longitudinal, transverse beams and columns and connected sheet metal parts. The skeleton of most passenger cars is obvious, but the skeleton of car body and truck cab is not obvious. Body shell usually includes sound insulation, heat insulation, vibration prevention, corrosion prevention, sealing and other materials and coatings laid on it.
2. The door is installed on the body shell through the hinge, which has a complex structure and is an important part to ensure the performance of the body. Metal sheet, etc. These sheet metal parts form a space for accommodating parts such as engines and wheels.
3. Exterior body decorative parts mainly refer to decorative strips, wheel decorative covers, signs, embossed characters, etc. Radiator masks, bumpers, headlights, rearview mirrors and other accessories are also obviously decorative.
4. Interior decoration includes surface decoration such as dashboard, ceiling, side walls and seats, as well as curtains and carpets. Surface decoration materials such as natural fiber or synthetic fiber textiles, artificial leather or multi-layer composite materials, and skin-attached foam plastics are widely used in automobiles. A large number of decorative materials such as fiberboard, cardboard, engineering plastic board, aluminum board, patterned rubber board and composite decorative board are used on buses.
5. Body accessories include: door lock, door hinge, glass lifter, various seals, wiper, windshield washer, sun visor, rearview mirror, handle, cigarette lighter, ashtray, etc. Modern cars are often equipped with radios and rod antennas, and some cars are also equipped with wireless phones, televisions, small stoves for heating food and small refrigerators.
6. Ventilation, heating, cooling and air conditioning devices inside the car body are important devices to maintain the normal environment inside the car and ensure the safety and comfort of drivers and passengers. Seat is also one of the important devices in the car body. The seat consists of a skeleton, a seat cushion, a backrest and an adjusting mechanism. Cushion and backrest should have certain elasticity. The adjustment mechanism can make the seat move back and forth or up and down, and adjust the inclination angle of the seat cushion and backrest. Some seats also have elastic suspension and shock absorbers, which can be adjusted to ensure that the height of the seat cushion from the floor is appropriate under the different weight of the driver. Some truck cabs and buses are also equipped with sleepers suitable for long-distance driving at night.
7. In order to ensure driving safety, modern cars widely use seat belts, headrests, airbags and various cushion devices to restrain passengers. According to the different types of goods transported, the truck body can be a common rail-plate structure, a platform structure, an inclined structure, a closed car body, a gas-liquid tank and a special container for pneumatic blowing and unloading for transporting bulk goods (grains, powder, etc.). ) or containers of various standard specifications suitable for highway, railway, waterway, air combined transport and international combined transport.
4. Electrical equipment: Electrical equipment consists of power supply and electrical equipment. The power supply includes storage battery and generator; Electrical equipment includes the starting system of engine, the ignition system of gasoline engine and other electrical equipment.
1. Battery: The function of the battery is to supply power to the starter and to the ignition system and other electrical equipment when the engine starts or runs at low speed. When the engine is running at high speed, the generator generates enough electricity, and the battery can store excess electricity. Each battery cell has a positive electrode and a negative electrode.
2. Starter: Its function is to convert electric energy into mechanical energy, drive the crankshaft to rotate and start the engine. When using the starter, it should be noted that the starting time should not exceed 5 seconds each time, the interval between each use should not be less than 10- 15 seconds, and it should be used continuously for no more than 3 times. If the continuous starting time is too long, it will cause a lot of discharge of the battery and overheating and smoking of the starting coil, which will easily damage the parts.