N basic knowledge about cars
What parts are included in the basic structure of a car?
Answer: The basic structure of a commonly used automobile is made up of four parts, which are: engine, chassis, body and electrical equipment parts.
The engine, as the heart of the car, is a complex machine composed of many institutions and systems. There are many different forms of automobile engine structure, but their basic structures are similar.
The chassis is composed of four major systems: transmission system, driving system, steering system, and braking system, and its role is to accept the power of the engine so that the car can move and ensure that the car can be operated in accordance with the driver's operation and normal driving.
The body is the skeleton of the car, but also the most intuitive part of the car, the body of the car is now more mature technology, the overall difference is not big.
Electrical equipment is mainly composed of power supply, power equipment, power distribution, etc. The power supply part is the battery and generator, the general battery in the engine start, to the starter motor power supply, and then the engine work, to the battery charging, and so on and so forth. Power equipment is more, the car with electricity are. The power distribution device is mainly composed of the central junction box, circuit switches and so on.
What parts make up a four-stroke gasoline engine?
A: Four-stroke gasoline engine consists of the body, crank connecting rod mechanism, air distribution mechanism cooling system, lubrication system, fuel system and ignition system (diesel engines do not have an ignition system) and other components.
How does a four-stroke gasoline engine perform its work cycle?
Answer: The working process of the engine is divided into four processes: intake, compression, work, exhaust. A four-stroke engine accomplishes these four processes within four strokes of the piston's up-and-down motion.
Intake stroke: the intake valve is open and both exhaust valves are closed. As the piston moves from the upper stop to the lower stop, the volume above the piston increases and the pressure in the cylinder decreases, creating vacuum suction. The combustible gas mixture is drawn into the cylinder.
Compression stroke: intake and exhaust valves are closed, and the piston moves from the lower stop to the upper stop, pressing the gas mixture into the combustion chamber.
Working Stroke:
At the end of compression, the intake and exhaust valves are still closed, the spark plug sends out an electric spark to ignite the combustible mixture, the burning gas expands violently, generating enormous pressure, forcing the piston to move downward rapidly, and pushing the crankshaft to rotate through the connecting rod to work.
Exhaust Stroke:
The exhaust valve opens, the intake valve closes, and the piston moves from the lower stop to the upper stop to remove the exhaust gas.
What is the role of the body and crank linkage mechanism and what are the major parts?
Answer: the role of the body and crank connecting rod mechanism is: combustion of fuel in the cylinder gas pressure on the top of the piston, with the help of connecting rods into the crankshaft torque, so that the crankshaft drives the working machine to do the work, the body and the crank connecting rod mechanism of the main parts of the cylinder block, cylinder head, piston, connecting rods, crank, flywheel and so on.
Describe the role and composition of the air distribution mechanism?
Answer: the role of the gas distribution mechanism according to the needs of the work, the timely opening and closing of the intake and exhaust valves, timely introduction of gas into the cylinder and exhaust gas. At the same time, drive the distributor, gasoline pumps and other components to work. The main parts of the gas distribution mechanism include: intake valve, exhaust valve, camshaft drive components.
Describe the role and components of cooling system?
Answer: The role of the cooling system is to dissipate the heat from the hot components into the atmosphere to keep the engine at a normal temperature. Water cooling system generally consists of engine water jacket, water pump, radiator, fan, thermostat, water temperature gauge and drain switch and other components.
What is the normal engine water temperature? How to control the water temperature?
A: The normal working temperature of water-cooled engine should be 80-90 degrees. The temperature of the engine to liberation CA10B type car, for example, according to the temperature of the engine, pull out (i.e., open) or launch (i.e., open and close) in the cab shutter maneuvering handle, change the amount of air into the radiator, so as to adjust the engine temperature.
What is the purpose of lubricating oil?
A: Lubrication: lubricate each friction parts, reduce friction resistance, can reduce power consumption.
Cooling effect: the flow of oil circulation, can be the friction belt away. Reduce the temperature of the machine parts.
Cleaning effect: the impurities on the surface of the machine parts will be flushed away, reduce wear and tear.
Sealing effect: keep the oil layer between the piston and the cylinder wall, can increase the sealing.
How do I check the engine oil level?
Answer: When checking the oil level of the oil pan, you should park the car in a flat place, stop the engine and wait for a few moments, pull out the dipstick, wipe off the oil on the surface, and then insert the dipstick tube from the mouth of the dipstick to the bottom, so as to determine the amount of oil.
Say what is the normal oil pressure in gasoline and diesel engines?
Answer: Observe the oil pressure gauge on the dashboard of the driver's cab: the normal oil pressure of a gasoline engine is 200-500 kPa; that of a diesel engine is 600-1000 kPa.
What kinds of devices are available for carburetors? What is the function? A: The construction of carburetor can be divided into five devices:
A: starting device; idling device; medium load device; full load device; acceleration device.
The function of the carburetor is: according to the needs of the engine in different situations, gasoline gasification, and mixed with air in a certain proportion into a combustible mixture. Timely and appropriate amount into the cylinder.
How does a diaphragm gasoline pump work?
Answer: oil suction: when the cam rotates the eccentric wheel topples the pump oil rocker arm. Pull down the pump membrane, the spring is compressed, at this time the volume above the pump membrane increases, the pressure decreases, resulting in suction, so that the outlet valve is closed, gasoline from the tank through the gasoline filter inlet valve, into the pump chamber.
Oil delivery: the cam continues to rotate, the eccentric wheel turned, *** oil rocker arm spring pushed back, the pump membrane spring pushes the pump membrane to the top, the gasoline in the pump chamber will be from the discharge flash pressure sent to the carburetor float chamber.
What are the major components of the driveline? What role does it play?
Answer: The driveline is composed of a clutch, transmission (and splitter), drive shaft, universal joints, reducer, differential, half shafts and other components. The role of the driveline: the engine output power to the driving wheels, drive the car.
What is the function of a clutch?
Answer: The function of the clutch is to enable the engine power to combine with the transmission smoothly or to separate it temporarily, so as to facilitate the driver to carry out the starting, stopping, shifting and other operations of the automobile.
What is the function of differential?
Answer: when the car turns, both sides of the vehicle at the same time the distance traveled is not equal, the outer wheels do not move the distance of the inner wheel is not large, and thus the planetary gears on the cross shaft of the differential by the influence of wheel resistance. At the same time in the rotation of the rotation, automatically increase the speed of the outer wheels, so that the outer wheels to speed up, the inner wheels become slower and play the role of the differential. When driving in a straight line. The differential does not work.
What checks should be done on tires in use?
A: check tire wear, if the tire wear is too much, the braking effect will be reduced (and road friction is reduced) when the braking distance lengthened, high-speed driving is easy to burst, such tires should be replaced in a timely manner. Insufficient tire pressure or uneven tire pressure on the left and right sides, will also cause poor braking effect, steering difficulties or heavy steering, but also reduces the service life of the tire. When the load is heavy, the above consequences are more serious. Therefore, tires should be inflated in time when the air pressure is insufficient. Left and right wheels should choose the same specification, type of tire, wear degree should be the same. Otherwise, it will affect the vehicle's steering mechanism dynamic performance. Check the tire ground there is no breakage, damage or tread on the foreign body (such as nails), two rear wheels at the seam of the debris, to be removed in time.
What are the components of the steering system? How is it steered?
Answer: The steering system is generally composed of three parts: the steering maneuvering mechanism, the steering gear and the steering mechanism. When turning the steering wheel, the steering shaft and worm gear with the rotation, rolling and worm gear engagement up and down movement, so that the steering rocker arm swing, pushing the straight rod back and forth. So the rotating section with the steering main pin as the center, drive one side of the front wheel deflection, to achieve the purpose of controlling the vehicle steering.
What is front wheel alignment? What does it include?
Answer: In order to make the car to maintain a stable straight line driving, steering light, reduce the car in the exercise of tires and steering parts of the wear and tear, the front wheels, steering pin, the front axle between the three installations have a certain relative position, which is called "front wheel alignment". It includes front wheel camber, front wheel front speed speed, steering knuckle main pin camber and steering knuckle main pin tilt.
What is the function of the hand brake?
Answer: Hand brake is a kind of braking device to keep the car from skidding when it is parked, and in special cases, it is used in conjunction with the foot brake for emergency braking or when the foot brake fails to work.
What are the components of an air brake? How does it work?
Answer: pneumatic braking device consists of brake pedal, air compressor, air pressure gauge, brake method, brake chamber, wheel brake, brake lines and other components. When stepping on the brake pedal, the brake valve opens the storage cylinder to the brake air chamber channel, so that the compressed air in the storage cylinder through the brake valve into the brake air chamber, through the transmission mechanism, to promote the brake shoes open, in order to tighten the brake drum, so as to make the wheels to produce braking effect.
What are the components of a hydraulic brake? How does it work?
A: Hydraulic braking device by the brake pedal, brake master cylinder, brake wheel cylinder, wheel brake, brake roll, piping and other components. When the brake pedal is depressed, the piston pushes the master cylinder forward. The brake fluid in the cylinder generates pressure, which presses the oil well tubing into each brake wheel cylinder. At this time, the wheel cylinder piston outward opening, push the brake shoes and brake drum contact, produce braking effect.
What is the role of the battery?
Answer: the role of the battery is to supply electricity to the engine, the engine. In the engine running at low speeds, the engine power generation is insufficient to supply lighting, audio devices, ignition system power; when the engine running at high speeds. When the generator generates enough electricity, store excess electricity. The charging and discharging of the battery can be shown by the ammeter.
How to use and maintain the battery?
Answer: Keep it clean, remove the dust and oxides in time. Battery cables and battery terminals are firmly installed. The battery's electric junction liquid should be higher than the level plate 10-15 millimeters. Insufficient should be added in time. Check the specific gravity of electrolyte frequently. Generally it should be kept between 1.220-1.260. Avoid violent discharge, such as the use of starting time should not be too long.
What is the role of the ignition system?
Answer: the role of the ignition system: the battery or generator output of low-voltage power point ignition coil into high-voltage electricity, and then by the distributor according to the engine cylinders in the order of work, take turns to the spark plugs caused by the spark, ignition of the combustible mixture, so that the engine running.