Basic Structure of Automobile

Document directory

• (1) Engine
• (2) Chassis
• (3) Body
• (4) Electrical Equipment

Basic Structure of Automobile

Modern cars are composed of multiple devices and mechanisms. The basic structure of vehicles produced by different models, types, and manufacturers is composed of four parts: Engine, chassis, electrical equipment, and body.

(1) Engine

An engine is a device that powers an automobile. Its role is to make fuel combustion generate power, and then drive the car through the chassis drive wheel. There are two types of engines: gasoline engine and diesel engine.

Modern cars widely use reciprocating piston internal combustion engines. It produces pressure by burning and expanding the combustible gas in the cylinder, pushes the piston movement, and rotates the crankshaft through the connecting rod to output power externally. It consists of two main mechanisms and five major systems: Crank-linkage mechanism, distribution mechanism, fuel supply system, ignition system (gasoline engine), start system, cooling system and Lubrication System. The ignition mode of the diesel engine is pressure-burning, so there is no fire.

1. Crank-Linkage Mechanism

It is mainly composed of cylinder, piston ring, connecting rod, crankshaft and flywheel. The upper part of the cylinder is the cylinder and the lower part is the crankcase. The piston is located in the cylinder. The piston ring is used to fill the gap between the cylinder and the piston to prevent the gas in the cylinder from leaking into the crankcase. The crankshaft is installed in the crankcase. The flywheel is fixed at the backend of the crankshaft and stretched out outside the engine cylinder to provide external power. The connecting rod is used to connect the piston and crankshaft to transmit the power and motion between the two. An automobile engine is a multi-cylinder engine. The number of pistons and connecting rods is the same as the number of cylinders, but there is only one crankshaft.

2. Distribution Mechanism

This mechanism is mainly composed of camshaft, valve and Valve Drive. Each cylinder has an intake valve and an exhaust valve, which are located at the inlet and exhaust ports respectively. They are responsible for closing and opening the inlet and exhaust ports. The camshaft is driven by the crankshaft by the timing gear or toothed belt, and the valve is regularly opened through the valve transmission component, filling fresh liquid into the cylinder or removing the Combustion Exhaust gas from the cylinder.

3. Gasoline Engine Fuel Supply System

It is mainly composed of air filter, carburetor (or fuel injection device), air intake tube, exhaust pipe, muffler, gasoline pump and fuel tank. The main function is to mix gasoline with air after atomization and evaporation into a combustible mixture of different concentrations into the cylinder for combustion. At the same time, the combustion exhaust gas is excluded from the cylinder. The amount of gas entering the cylinder is controlled by the driver through the accelerator pedal to meet the needs of different engine loads.

4. Diesel Fuel Supply System

It is mainly composed of air filter, intake pipe, exhaust pipe, muffler, diesel fuel tank, oil pump, injector, etc. Air enters the cylinder through the air filter and air intake tube. The diesel in the diesel tank is extracted by the oil pump and enters the fuel injection pump. After the fuel pump is pressurized, the injector is sprayed into the cylinder combustion chamber in a fog. Diesel fuel is evaporated in the combustion chamber, and is self-ignited after mixing. The combustion exhaust gas is discharged from the exhaust pipe. The driver controls the amount of diesel fuel injected into the cylinder each time based on the engine load through the accelerator pedal.

5. Ignition System

The ignition system is exclusive to gasoline engines and consists of battery, ignition switch, distributor assembly, ignition coil, high voltage wire and spark plugs. Spark plugs are located in the cylinder combustion chamber. The main function of the system is to make spark plugs generate spark on time, and ignition the combustible mixture in the cylinder while doing work. The combustion mode of a diesel engine is self-ignited (pressure-burning) with no ignition.

6. cooling and Lubrication System

The cooling and Lubrication Systems are responsible for protecting the normal operation of the engine and providing a long service life for the engine. The cooling system is mainly composed of a water pump, a radiator, a fan, a water jacket, and a thermostat. It is responsible for making the engine have a proper operating temperature. The lubrication system is composed of oil pumps, oil filters, main oil channels, and oil pan. It provides lubrication, cooling, cleaning, and sealing functions on the engine.

7. Start the system

It is mainly composed of a battery, startup control, transmission mechanism, and motor. It is used to start the engine and put it into operation.

(2) Chassis

The role of the 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 generates motion and ensures normal driving. The chassis is composed of a power train, a driving system, a steering system, and a brake system.

1. Transmission

The transmission system consists of a clutch, a transmission, a universal transmission device, and a drive axle. It is used to transmit the power output from the engine to the drive wheel and adapt it to the needs of driving cars.

The clutch is fixed on the rear face of the flywheel of the engine and connected to the transmission. The clutch is often in the joint State. When the driver step on the clutch pedal, the clutch is separated and the power transmission is interrupted for START, shift and brake operations. The clutch also provides overload protection for the transmission system through slipping.

There are several forward gears and one reverse gear on the transmission. The transmission ratios of different transmission gears are different, which can meet the needs of vehicles with different driving resistance and different vehicle speeds. Reversing enables reverse driving. "Neutral block" can interrupt power transmission.

The universal transmission device is located between the transmission and the drive axle, and transmits the power output from the transmission to the drive axle.

The drive axle is composed of the main drive axle, Differential Axle, half axle and axle housing. One of the bridges (mostly the rear axle) is the drive axle, which drives the car. The other bridge (mostly the front axle) is the driven axle, cannot drive. However, all the axles of a cross-country vehicle are driving axle. Therefore, a driver is placed behind the transmission to distribute power to each bridge.

2. Traveling System

The driving system is the foundation of a car. It consists of a frame, a axle, a wheel and a tire, and a suspension device located between the axle and the frame. The frame is the assembly matrix of an automobile, and the whole automobile is loaded into one. The axle and the wheel are responsible for the driving and suspension of the car. The frame is the assembly matrix of an automobile, and the whole automobile is loaded into one. The axle and the wheel are responsible for driving the car. The suspension device installs the axle on the frame and acts as a force transmission, guide, and buffer damping function. In addition to the control and stability of the vehicle, the driving system also has an important impact on the seat comfort of the vehicle.

3. Steering System

The steering system is used to change or restore the vehicle's travel direction. It enables steering by deflection of the front wheel to a certain angle relative to the vehicle's longitudinal plane. The steering system is mainly composed of steering mechanisms, Steering gears, and steering motors.

4. Braking System

The purpose of the braking system is to quickly slow down the car in progress until it stops. It is a reliable place for parked cars to stay in place. The Vehicle Brake Device consists of a brake and a brake control mechanism on each wheel, which is operated by the driver through the brake pedal. The brakes of the parking brake device are mounted on the second shaft of the transmission, but most of them are integrated with the rear axle brake. the parking brake is operated by the hand joystick.

(3) Body

The body contains drivers, passengers, and cargo, and forms the housing of the car. The truck body is composed of the cargo compartment of the cab. The passenger car and the car body are composed of a unified shell. Other dedicated vehicles include other special equipment. The car body also includes doors, windows, car locks, interior and exterior ornaments, accessories, seats, and sheet metal parts before the car.

(4) Electrical Equipment

Electrical equipment consists of power supply and power equipment. The power supply includes generators and batteries. There are a lot of electric equipment content, different models are not the same, mainly including the fire, starting system, lighting, instrumentation signal system, air conditioning and other electrical equipment.