1.carThe basic structure of which includes those parts? Answer: Generally, the basic structure of commonly used cars is composed of four parts: the engine, the chassis and the electrical equipment.
2. What are the parts of a four-range gasoline engine? Answer: The four-stroke gasoline engine is composed of a body, a crank connecting rod mechanism, a valve train cooling system, a lubrication system, a fuel system and an ignition system (the diesel engine does not have an ignition system).
3. How does the four-stroke gasoline engine work cycle? Answer: The working process of the engine is divided into four processes: intake, compression, work, and exhaust.The four-stroke engine combines these four processes inpistonCompleted within four strokes of the up and down movement.Intake stroke: inValveOpen, exhaust valves are closed. As the piston moves from the top dead center to the bottom dead center, the volume above the piston increases and the pressure in the cylinder decreases, resulting in vacuum suction. Inhale the mixed gas into the cylinder. Compression stroke: The intake valve and exhaust valve are closed, and the piston moves from bottom dead center to top dead center to press the mixed gas into the combustion chamber. Working stroke: when the compression ends, the intake valve and exhaust valve are still closed,Spark plugAn electric spark is emitted to ignite the combustible mixture. The combusted gas expands violently, generating huge pressure, forcing the piston to descend rapidly and pushing it through the connecting rod.CrankshaftRotate and work. Exhaust stroke: The exhaust valve opens, the intake valve closes, and the piston moves from bottom dead center to top dead center to remove exhaust gas.
4. What are the functions and main parts of the body and the crank connecting rod mechanism?Answer: The function of the body and the crank connecting rod mechanism is: the pressure of the gas acting on the top of the piston when the fuel is burned in the cylinder is changed intoCrankshaftThe high torque makes the crankshaft drive the working machinery to do work. The main parts of the body and crank connecting rod mechanism are cylinder block, cylinder head, piston, connecting rod, crank, flywheel, etc.
5. Explain the function and composition of the gas distribution mechanism? Answer: The function of the gas distribution mechanism is to open and close the intake and exhaust valves at the right time according to the work needs, and promptly introduce combustible gas into the cylinder and exhaust the exhaust gas.At the same time, driveDistributor, Gasoline pumps and other parts for work. The main parts of the valve train include: intake valve, exhaust valve,CamshaftDrive parts, etc.
6. Explain the composition of the role of the cooling system? Answer: The role of the cooling system is to dissipate the heat of high-temperature parts into the atmosphere to keep the engine working at normal temperature. The water cooling system is generally composed of the water jacket of the engine,Water pump,heat sink,fan,Thermostat, Water temperature gauge and water releaseswitchAnd other parts of the composition.
7. What is the normal water temperature of the engine? How to control the water temperature? Answer: The normal working temperature of water-cooled engine should be 80-90 degrees. Take the Jiefang CA10B automobile as an example for the engine temperature. According to the engine temperature, you can pull out (that is, open) or push out (that is, open and close) the operating handle of the blinds in the cab to change the amount of air entering the radiator to adjust the engine temperature.
8.lubricating oilWhat is the role of? Answer: The function of lubricating oil: lubricate all frictional parts, reduce frictional resistance, and reduce power consumption. Cooling effect: the circulating oil flows, which can remove the friction heat. Reduce the temperature of the machine parts. Cleaning function: wash away the impurities on the surface of the machine parts and reduce wear. Sealing function: keep the oil layer between the piston and the cylinder wall, which can increase the sealing performance.
9. How to check the oil level of the engine? Answer: When checking the oil level of the oil pan, the car should be parked in a flat place, the engine should stop running and wait a while, then pull out the oil dipstick, wipe off the oil on the surface, and then remove the oil from the dipstick nozzle. Insert it to the end to determine the amount of oil.
10. What is the normal oil pressure of gasoline and diesel engines? Answer: Observe the oil pressure gauge on the dashboard of the cab: the normal oil pressure for gasoline engines is 200-500 kPa; for diesel engines it is 600-1000 kPa.
11.CarburetorWhat kind of devices are there? What is the role? Answer: The structure of the carburetor can be divided into five types of devices: Answer: starting device; idle device; medium load device; full load device; acceleration device. The role of the carburetor is: according to the needs of the engine in different situations, it vaporizes gasoline and mixes it with air in a certain proportion to form a combustible mixture. Enter the cylinder in an appropriate amount in time.
12. How does the diaphragm gas oil pump work? Answer: oil suction: when the cam rotates, the eccentric wheel pushes the pump oil rocker arm.Pull down the pump diaphragm and the spring is compressed. At this time, the volume above the pump diaphragm increases, the pressure decreases, and suction is generated, and the oil outlet valve is closed.tankGasolineFilterThe oil inlet valve enters the pump chamber. Fuel delivery: The cam continues to rotate. After the eccentric wheel has rotated, the common oil rocker spring pushes back, and the pump diaphragm spring pushes the pump diaphragm upward, and the gasoline in the pump chamber is flashed from the oil output to the carburetor float chamber.
13. What are the main components of the drive train? What does it do?Answer: The transmission system is mainlyclutch,transmission(as well asSplitter),transmission shaft, Universal joint, reducer, differential,Half shaftAnd other components. The role of the drive train: the power output from the engine is transmitted to the driving wheels to drive the car.
14. What is the role of the clutch? Answer: The function of the clutch is to smoothly combine or temporarily separate the power of the engine and the transmission, so that the driver can perform operations such as starting, stopping, and shifting the car.
15. What is the role of the gearbox?Answer: It is suitable for changing the driving resistance of the car, changing the torsion of the driving wheel andRotating speed. Move the car forward or backward. When in neutral, the power transmission is interrupted and the operation of the engine is separated from the movement of the vehicle.
16. What is the role of the differential? Answer: When the car turns, the distances traveled by the vehicles on both sides at the same time are not equal, and the distance of the outer wheel is not as large as that of the inner wheel, so the planetary gear on the differential cross shaft is affected by the wheel resistance. Rotation occurs at the same time of revolution, which automatically increases the speed of the outer wheels, speeds up the outer wheels, and slows down the inner wheels to act as a differential. When exercising in a straight line. The differential does not work.
17.tireWhat inspections should be paid attention to during use?Answer: checktireWear, if the tire is worn too much, the braking effect will be reduced (the friction with the road surface is reduced) and the braking distance will be lengthened, and it is easy to burst when driving at high speed. This type of tire should be replaced in time. Insufficient tire pressure or uneven tire pressure on the left and right sides can also cause jet lag, difficult steering or heavy steering, and also reduce the service life of the tires. When the load is large, the above consequences are more serious. Therefore, the tire should be inflated in time when the tire pressure is insufficient. The left and right wheels should choose tires of the same specification and model, and the degree of wear should be the same.Otherwise, it will affect the vehicle’sSteering machineBraking performance. Check whether the tire grounding surface is broken, damaged, or whether there are foreign objects (such as nails) on the tread. If there are gravels between the two rear wheels, remove them in time.
18. What are the components of the steering system? How did it turn? Answer: The steering system generally consists of three parts: steering control mechanism, steering gear and steering mechanism.When turningsteering wheelAt this time, the steering shaft and the worm rotate with this, and the rolling meshes with the worm to move up and down, so that the steering rocker arm swings and pushes the straight pull rod to move back and forth. Therefore, the turning knuckle is centered on the steering king pin to drive the deflection of the front wheel on one side to achieve the purpose of controlling the steering of the vehicle.
19. What is front wheel positioning? What is included? Answer: In order to keep the car running in a stable straight line, the steering is light, and to reduce the wear of the tires and steering parts during the operation of the car, the installation of the front wheel, the steering king pin, and the front axle has a certain relative position, which is called "Front wheel alignment". It includes front wheel camber, front wheel speed,Steering knuckleThe kingpin tilts inward and the steering knuckle tilts backwards.
20. HandsBrakeWhat is the role of? Answer: The hand brake is a braking device that prevents the car from slipping when it is parked. Under special circumstances, it is used in times of emergency braking with foot movement or failure of foot movement.
21. What are the components of the pneumatic brake device? How does it work?Answer: The pneumatic braking device is composed ofBrake pedal,Aircompressor, Barometer, braking method, brake chamber, wheel brake, brake pipeline, etc. When you step on the brake pedal,Brake valveOpen the passage from the air reservoir to the brake air chamber, so that the compressed air in the air reservoir enters the brake air chamber through the brake valve, and pushes the brake shoe to open through the transmission mechanism to compress the brake drum, thereby causing the wheels to produce Braking effect.
22. What are the components of the hydraulic brake device? How does it work? Answer: The hydraulic brake device is composed of brake pedal, brake master cylinder, brake wheel cylinder, wheel brake, brake roller, pipeline and so on. When the brake pedal is stepped on, the piston pushes the master cylinder forward. Make the brake fluid in the cylinder generate pressure, and press the oil into each brake wheel cylinder through the oil pipe. At this time, the wheel cylinder piston expands outward, pushing the brake shoe into contact with the brake drum, producing a braking effect.
twenty three.AccumulatorWhat role does it play? Answer: The function of the battery is to supply electricity to the engine. When the engine is running at low speed and the engine’s power generation is insufficient, it is necessary to provide lighting, audio equipment,Ignition systemElectricity; when the engine is running at high speed.DynamoWhen the power generation is sufficient, the excess power is stored. The charging and discharging status of the battery can be displayed by an ammeter.
24. How to use and maintain the battery? Answer: Keep it clean and remove dust, dirt and oxides in time. The battery cable and battery post are installed firmly. The electric condensate of the accumulator should be 10-15 mm higher than the grade. It should be added in time when it is insufficient. Always check the specific gravity of the electrolyte. Generally, it should be kept between 1.220-1.260. Avoid violent discharge, such as using the starting time not too long.
25. What role does the ignition system play?Answer: The function of the ignition system is to output the bottom piezoelectric scene of the battery or generator.Ignition coilsIt is converted into high-voltage electricity, and then distributed to the spark plugs in turn according to the work order of each cylinder of the engine by the distributor to cause sparkover, ignite the combustible mixture, and make the engine run.
26. What is the function of the circuit breaker? Answer: The function of the breakpoint gas is to connect and cut off the low-voltage circuit, and the pilot fire coil generates high-voltage current.
27. What are the main lights of the car? answer:Headlamp(Including high beam, low beam), front position light, rear position light, license plate light,Instrument lights,Turn signal, Brake lights, hazard warning flashes, reversing lights, frontFog lightsWait.
28. What is the routine maintenance of vehicles? Why should the driver do a good job of routine maintenance of the vehicle? Answer: Routine maintenance is the additional function of inspection, cleaning, and tightening of the driver before leaving, during driving, and after receiving the vehicle. The situation of the various parts of the car is changing at any time. Failure or damage of mechanical parts may also occur when parked. If these faults cannot be discovered in time and carefully eliminated, it will directly affect the safety of driving, the life of the parts and the consumption of fuel and lubricating oil. Therefore, maintenance work must be done carefully.
29. What are the main items that should be checked before leaving the car? Answer: The items to be checked before the driver leaves the car: lubricating oil, fuel, cooling water, hand and foot brake devices, speaker speakers, lighting devices, water hangers, steering devices, meters, tire pressure, tire nuts, etc.
30. What are the main items that should be checked during driving? Answer: When the car is running, the driver should check: A: Check the working conditions of various dashboards while driving. Check whether the steering system is working properly. Check whether the hand and foot brakes are working properly. Check the engine and chassis for abnormal noise and smell during operation. Use the parking time (usually about 50 kilometers for a car) to check the following items: Check whether the brake drums of the front and rear wheels are overheated by hand. Check the tightness of the tires and nuts, and remove the impurities in the tire pattern. Check for oil, water, and air leaks.an examinationLeaf springWhether it is broken, whether the connecting bolt of the drive shaft is loose. Check the strapping of the loaded goods, etc.
31. What are the main items to be checked and maintained after receiving the car? Answer: Check and replenish fuel and lubricating oil. Clean the interior and exterior of the vehicle and the engine and chassis.In severe winter, if the cooling system is not addedantifreezeWhen the radiator cover, the water drain switch, and the engine water drain switch are turned on, the cooling water should be drained, and a short-term start should be made to drain the water to prevent the residual water from freezing the cylinder, radiator, and air brake. The vehicle should drain the sewage in the air tank. After the flame is turned off, close the switch and tighten the hand brake to check for leakage of the ammeter (the pointer points to the "one" side). Check horns, lights, wipers. Check whether the leaf spring is broken, whether the spring lugs and riding bolts are loose. Check the axle shaft and tire nuts to see if the steel ring is damaged or cracked. Check whether the tires are cracked or flat.
32. What are the requirements for the first-level maintenance of the vehicle? Answer: After the first-level maintenance work is completed, the car should be neat and tidy, the connection should be firm, the three filters should be unobstructed, no oil, water, air, and electricity should be leaked.
33. What are the cleaning operation items for the first-level maintenance of vehicles? Answer: Maintenance and cleaning operation items: Answer: Clean the body and wipe the engine and chassis parts.Cleaning and maintenanceair filter, Clean the gasoline filter and releaseOil filterIn the sediment, turn the filter handle 3-4 turns, clean the oil filter, and replace the filter element according to the degree of pollution. Release the oil and water accumulation in the air reservoir.
34. What are the primary maintenance and lubrication tasks for vehicles? Answer: Maintenance and lubrication work items: Answer: Check the engine, transmission,Rear axle, Oil level of steering gear, add lubricating oil according to regulations. The fuel nozzles of each part of the vehicle are fully equipped and effective.Steering rodEtc.) Grease.
35. What are the first-level maintenance, inspection, and fastening work items for vehicles? Answer: Maintenance, inspection, and tightening work items: Answer: Check the steering gear, tie rods, tie rods, and the connection and tightening of each steering arm.Check and adjust the aircompressor, Engine and fanbeltTightness and fixation. Check the brake method and brake pipeline for air leakage, check the brake fluid level of the hydraulic brake master cylinder, and add brake fluid as required.Check and adjustClutch pedal, The free stroke of the brake pedal, check whether the fixed shaft of the brake pedal and the split pin are intact and reliable. Check and tighten the connections and bolts of all parts of the vehicle. Check the tire pressure and check whether the tires are damaged. Check the battery shell, dredge the vent hole of the small cover, and make up the electrolyte. Check whether the lights, wiring, and wiper switches are complete and intact. Whether the speaker volume tone is normal, and whether the various instruments are working well.
36. What are the common faults of gasoline engine oil circuit? Answer: The common oil circuit faults of gas oil engines are generally three types: plugging, leaking, and broken. Frequent failures include: the fuel tank switch is not turned on or the bottom of the fuel tank is too dirty, the fuel pipe is blocked or the fuel tank is out of oil. Gasoline filter or carburetor oil inlet pipe joint filter is blocked or oil pipe joint is loose, the horn mouth is broken and oil leaks. Gasoline pump failure or air lock in the oil circuit. The main oil passage of the carburetor is blocked or the triangular needle valve is stuck and no oil enters.
37. Briefly describe how to check whether there is oil in the oil pipe of the carburetor? Answer: Remove the connecting oil pipe of the carburetor, turn the oil pump handle of the oil pump by hand or use the crank handle of the starter to turn the engine to observe.
38. How to adjust the idle speed? Answer: Engine idle speed adjustment method: When the engine idling speed is unstable, it should be adjusted when the engine temperature is normal and the oil and circuit are not faulty.usescrewdriver(Commonly known as screwdriver, screwdriver) slowly releaseThrottleWhen the opening adjustment screw is about to turn off, screw in a little bit to keep the engine running. Adjust the idle speed mixture adjusting screw. Bring the engine to speed. (3) Rotate out the valve opening adjustment again to achieve stable idling operation, and it will accelerate without stalling.
39. How to use a screwdriver to break the fire to test the working conditions of each cylinder of the engine? Answer: After the ignition of a certain cylinder is disconnected with a screwdriver, and the engine running does not change, it can be considered that the cylinder is working or working badly. 40. What faults often occur in the ignition system? Answer: The ignition system faults of gasoline engines are generally: low-voltage open circuit, low-voltage short circuit, high-voltage weak fire, disordered ignition, irregular ignition time, etc.
41. How to check the breaker contact gap? Answer: There is a certain gap when the disconnection contacts of the distributor are separated. If the gap is too small, the contacts will be easily ablated during flashover; if the gap is too small, the contact closure time will be short, reducing the low-voltage current passing, and the generator will be prone to flameout when the generator rotates at high speed. The general gap is 0.35-0.45 mm.When adjusting, remove the distributor andSplit fire head, Rotate the crankshaft to fully open the output, loosen the fixing screw of the fixed contact, adjust the eccentric screw, measure the required gap with a thickness gauge, and then tighten the fixing screw of the fixed contact.
42. How to check the quality of the ignition coil?Answer: Inspection of the ignition coil: Answer: Remove the low-voltage connector of the distributor and open itIgnition SwitchAfter that, touch the ground. If the spark is good, it proves that there is no fault in the low-voltage circuit before entering the distributor.willDistributor coverIn the center jackHigh-voltage linePull it out so that its end is close to the cylinder body 7-8 mm, and then use a screwdriver to pull up the contact arm to open and close the contact.At this time, a strong high-voltage spark is generated at the end of the central high-voltage wire. If there is no high-voltage spark or weak, it means that the ignition coil is faulty orcapacitanceFailure, etc.
43. How to check the quality of the distributor and the distributor? Answer: Inspection of the distributor cover: Check whether there are cracks on the distributor cover, and check with high-voltage sparks. Remove the distributor, hold all the high-voltage wires in one hand, make the ends of the cylinder lift 3-4 mm, turn on the ignition switch, use a screwdriver to move the contact arm to open and close the contact. If there is a high-voltage spark skipping from a certain branch end, it means that the electrical cover has been damaged. Inspection of the spark splitter: turn the spark splitter over, put it on the cylinder head, and then press the center cover of the distributor cover to make the end appear, and start fire at a distance of about 7-8 mm from the spark splitter cavity. If the spark splitter is well insulated, high-voltage sparks will not skip, otherwise it means the spark splitter has been damaged.
44. How to check the quality of the capacitor? Answer: Inspection of the capacitor: Poor work or failure of the capacitor will weaken the high-voltage sparks, and the power-off contacts are often burnt. The inspection method is: remove the central high-voltage line of the distributor cover, 5-7 mm away from the cylinder, and open it. Turn on the ignition switch, flip the breakpoint contact to observe the high-voltage flashover, and then remove the capacitor wire to observe the high-voltage flashover. At this time, the spark should be greatly weakened. replace.
45. Direction adjustment of the free stroke of the clutch pedal? Answer: The free stroke of the clutch pedal should be 20-30 mm. When the clutch cannot be completely separated or slips due to friction, the free stroke of the clutch pedal should be adjusted. If you want to reduce the free stroke of the pedal, you can tighten the spherical nut of the separating rod. If you want to increase the free stroke, you should loosen the spherical end.
46. What is the reason for the unstable direction? Answer: The clearance of the transmission mechanism in the steering gear is too large. The ball joints of the horizontal and control tie rods are worn loose.Turn toKingpinThe matching clearance with the bushing is too large.Front wheelWheel hubThe bearing is loose. Misalignment of the front wheels.
47. What is the reason for the heavy turn?Answer: The reasons for the heavy steering are: Answer: Horizontal and lever controlBall pinToo tight or lack of grease. The knuckle pin and the bushing are too tight or the thrust bearing lacks grease. Misalignment of the front wheels.
48. What are the reasons for insufficient braking force and weakened braking efficiency? Answer: The air pressure is insufficient (air pressure type), and the oil level of the oil storage tank is too low (hydraulic type). The pedal free stroke is too large. The control valve die is broken or dented (air pressure type), and oil is leaking from the piston cup of the master cylinder (hydraulic type). The brake air chamber is touched or damaged (air pressure type), and oil is leaking from the wheel cylinder piston cup (hydraulic type). The exhaust valve of the control valve has a poor seal (air pressure type). The pipe joint is loose or the pipe is ruptured and leaks air or oil. Improper adjustment of the brake shoe and brake clearance, oil or muddy water on the shoe skin.
49. What are the reasons why the braking effect is not eliminated after braking? Answer: During driving, when the brake pedal is released, the braking force does not decrease. The car cannot start or it is difficult to drive after starting. The reasons are as follows: the stroke adjustment of the control valve arm and exhaust valve is improper or the exhaust valve spring is broken, and there is rust. Dirt sticks the exhaust valve and prevents the valve from opening. The brake cylinder push rod is extended too long or the oblique ear is stuck. There is dirt on the brake cam or the axis of the cam bracket and the axle bracket on the brake disc are not in a straight line. The four-position spring of the brake shoe is too soft. The clearance between the brake air chamber shoe and the brake drum is too small. The brake shoe support pin is displaced or rusted. There is water in the brake chamber (ice in winter) and it squeezes the diaphragm of the brake chamber.
50. What are the phenomena and causes of braking deviation? Answer: When braking, the left and right wheels have different braking effects, causing the wheels to skew to one side. The reasons are as follows: individual brake chamber die rupture, brake wheel cylinder cup oil leakage or air pipe or oil pipe rupture, loose joints Air leak. Individual brake cylinder push rods are skewed or bent and jammed. The brake arm camshaft is stagnant with rust. The gap between the left and right wheel brake shoes and the brake drum is different, and the material of the friction lining is different or the contact condition is different. The brake shoes of individual wheels are rusty on the support pins and cannot rotate freely. The brake pads of individual wheels are oily and muddy or hardened, worn out or even exposed rivets. The individual brake drum wears a loss zone with grooves. The left and right tires have uneven air pressure.
Email: