The carburetor is a mechanical device that mixes a certain proportion of gasoline and air under the vacuum generated by the engine’s operation. As a precision mechanical device, the carburetor uses the kinetic energy of the inhaled air flow to atomize gasoline. Its important role in the engine can be called the “heart” of the engine. The complete device should include starting device, idle device, medium load device, full load device and acceleration device. The carburetor will automatically proportion the corresponding concentration and output the corresponding amount of mixed gas according to the different working conditions of the engine. In order to make the mixed gas mixture evenly mixed, the carburetor also has the function of atomizing the fuel. effect for the machine to operate normally.     Classification Carburetors are divided into simple carburetors and complex carburetors. Carburetors can also be divided into downdraft and flat-draft types. Carburetors can be divided into rotary type and lift type based on the type of throttle valve. The rotary throttle is a disc-shaped throttle that rotates around an axis between the carburetor throat and the intake pipe to change the flow area of the intake duct. The lift-type throttle is constructed as a barrel-shaped plate-shaped throttle, which moves up and down at the throat to change the channel area at the throat. This form is often used in motorcycle carburetors. There is also a type of carburetor that is a hybrid form of the two. The rotary throttle is controlled by a human and the lift throttle is controlled by a diaphragm. This is also often used on motorcycles and is called the CV type. Structure A simple carburetor consists of upper, middle and lower parts. The upper part has the air inlet and float chamber, the middle part has the throat, measuring hole and nozzle, and the lower part has the throttle valve, etc. The float chamber is a rectangular container that stores gasoline from the gasoline pump. There is a float in the container that uses the height of the floating surface (oil surface) to control the amount of fuel. The oil inlet at one end of the middle nozzle is connected to the measuring hole of the float chamber, and the oil outlet at the other end is at the throat of the throat. Principle A carburetor is essentially a tube with an adjustable plate in the middle called a throttle plate that controls the flow of air through the tube. There is a constriction in the tube called a venturi where a vacuum is created. This constriction has a measuring hole through which fuel can be sucked in using a vacuum. Atmospheric pressure spreads from high pressure to low pressure. When the piston of a two-stroke engine is at top dead center (or the piston of a four-stroke engine is at bottom dead center), a low pressure develops under the piston in the crankcase (above the piston on a four-stroke engine). At the same time, this low pressure will also cause low pressure in the carburetor. Because the pressure outside the engine and carburetor is higher, air will rush into the carburetor and into the engine until the pressures equalize. The air flowing through the carburetor will carry the fuel, which will then mix with the air. Inside the carburetor is a section of pipe. The throat is the constriction inside the carburetor that forces air to accelerate through it. A river that suddenly narrows can be used to illustrate what happens inside a carburetor. The water in the river will speed up as it approaches a narrowing bank, and even faster if the bank narrows continuously. If the same thing happens inside the carburetor, the accelerated flow of air will cause the air pressure inside the carburetor to decrease. The gasoline enters the carburetor from the fuel tank through the gasoline filter. The gasoline filter can filter out the impurities mixed in the gasoline and the oxide scale in the fuel tank. If the filter quality is defective, some impurities may still enter the carburetor through the filter. In addition, gasoline contains ingredients that can form colloid. After long-term deposition, colloid will condense and adhere to the parts of the carburetor (such as measuring holes), oil passages and the surface of the float chamber. The air enters the carburetor through the air filter. Considering that the air intake resistance cannot be too large and other factors, the filter device cannot be too dense, so some tiny impurities in the air will still enter the carburetor through the air filter. If the filter quality is defective, it will cause more serious effects. Many parts that make up the carburetor oil passage and air passage, such as the main metering hole, idle speed metering hole, main air metering hole, idle air metering hole, main foam tube, etc., all have holes with very small inner diameters (the inner diameter is 0.3 ~1.5mm), the gasoline impurities, colloids and impurities in the air that enter the carburetor will often change or block these pore diameters, causing the carburetor air passage and oil passage to be blocked and the carburetor supply Changes in oil properties may even cause carburetor performance failure. Maintain The normal maintenance of the carburetor is actually to maintain the cleanliness of the carburetor when it leaves the factory. This is controlled as a key indicator of carburetor quality assessment by professional carburetor manufacturers, who use various advanced equipment and processes to Every aspect of production is strictly controlled. Therefore, in order to ensure the normal use of the carburetor, attention must be paid to normal maintenance of the carburetor: clean the carburetor regularly, keep the oil passage and air passage of the carburetor clean, and keep the small holes unobstructed. This is also very important to extend the service life of the carburetor. Many carburetor performance problems can be solved by cleaning the carburetor regularly.

Car seat belts are safety devices designed to restrain the occupants during a collision and to prevent secondary collisions between the occupants and the steering wheel and instrument panel, or to prevent the occupants from rushing out of the car during a collision, resulting in death or injury. Car seat belts, also known as seat belts, are a type of passenger restraint device. Car seat belts are recognized as the cheapest and most effective safety devices. Among vehicle equipment, seat belts are mandatory in many countries.     Origin Seat belts existed before the invention of automobiles. In 1885, when horse-drawn carriages were commonly used in Europe, seat belts were simply used to prevent passengers from falling off the carriage. By 1910, seat belts began to appear on airplanes. In 1922, sports cars on the racing circuit began to use seat belts. By 1955, Ford cars in the United States began to use seat belts. Generally speaking, the seat belts during this period were mainly two-point seat belts. In 1955, aircraft designer Niels invented the three-point safety belt after working for Volvo Car Company. In 1963, Volvo Car Company began to register Niels’ three-point car seat belt and assemble it on its own cars. In 1968, the United States stipulated that all forward-facing seats in cars must be equipped with seat belts. Developed countries such as Europe and Japan have also successively formulated regulations requiring car occupants to wear seat belts. Structure 1. Webbing Webbing is a belt about 50mm wide and 1.2mm thick made of synthetic fibers such as nylon or polyester. Depending on the purpose, the strength, elongation, etc. required by the safety belt can be achieved through weaving methods and heat treatment. characteristic. It is also the part that absorbs conflicting energies. National regulations have different requirements for the performance of seat belts. 2. The retractor is a device that adjusts the length of the seat belt according to the occupant’s sitting posture, body shape, etc., and retracts the webbing when not in use. Divided into ELR and ALR. 3. Fixing mechanism The fixing mechanism includes buckles, lock tongues, fixing pins and fixing seats, etc. The buckle and tongue are the devices for fastening and unfastening the seat belt. The end of the webbing that is fixed to the body is called a fixing plate, the fixed end of the body is called a fixing seat, and the bolts used for fixing are called fixing bolts. The position of the shoulder safety belt fixing pin has a great impact on the convenience of fastening the safety belt. Therefore, in order to suit passengers of various sizes, an adjustable fixing mechanism is generally used to adjust the position of the shoulder safety belt up and down. Principle The function of the retractor is to store the webbing and lock the webbing from being pulled out. It is the most complex mechanical part in the safety belt. Inside the retractor is a ratchet mechanism. Under normal circumstances, the occupants can freely pull the webbing on the seat at a constant speed. However, once the continuous pulling process of the webbing from the retractor stops or when the vehicle encounters an emergency, the ratchet mechanism will act. The locking action automatically locks the webbing and prevents the webbing from being pulled out. Installation fixings are lugs, plug-ins, bolts, etc. that are connected to the car body or seat components. Their installation position and firmness directly affect the protective effect of the seat belt and the comfort of the occupants. Performance 1. Seat belt design elements Seat belts should be designed to meet the requirements of occupant protection performance, reminder to use seat belts, as well as comfort and convenience. The design means to achieve the above points are the selection of the position of the seat belt adjuster, the specifications of the seat belt and the auxiliary devices used. 2. Occupant protection performance The requirements for the occupant protection performance of car seat belts are as follows: restrain the occupant as early as possible; minimize the pressure on the occupant when restraining; keep the restraint position unchanged so that the restraint force avoids the more vulnerable parts of the human body. As a means to achieve the above goals, the use of the pretensioner and force limiter described above significantly improves the performance in these aspects.

The clutch is located in the flywheel housing between the engine and the gearbox. The clutch assembly is fixed on the rear plane of the flywheel with screws. The output shaft of the clutch is the input shaft of the gearbox. While the car is driving, the driver can depress or release the clutch pedal as needed to temporarily separate and gradually connect the engine and the transmission to cut off or transmit the power input from the engine to the transmission.     The clutch is a common component in mechanical transmission, which can separate or engage the transmission system at any time. Its basic requirements are: smooth joining, rapid and complete separation; easy adjustment and repair; small outer size; small mass; good wear resistance and sufficient heat dissipation capacity; easy and labor-saving operation. Commonly used ones are divided into tooth-embedded and There are two types of friction type. Definition The clutch, commonly known as Jilizi in Hong Kong, comes from the English Clutch. In Taiwanese, it is often called Lizi or Japanese クラッチ. It is a device that transmits the engine power of a car or other power machinery to the axle in the form of a switch. The clutch is installed between the engine and the transmission. It is an assembly in the automobile transmission system that is directly connected to the engine. Usually the clutch is installed together with the flywheel set of the engine crankshaft, and is the component that cuts off and transmits power between the engine and the vehicle’s transmission system. During the entire process from starting to normal driving of the car, the driver can operate the clutch as needed to temporarily separate or gradually connect the engine and the transmission system to cut off or transmit the power output from the engine to the transmission system. Its function is to gradually connect the engine and the transmission to ensure a smooth start of the car; to temporarily cut off the connection between the engine and the transmission to facilitate shifting and reduce the impact of shifting; and to activate the car when the car is under emergency braking. The separation function prevents transmission systems such as transmissions from being overloaded, thus playing a certain protective role. A clutch is similar to a switch, engaging or disengaging power transmission. The active part and the driven part of the clutch mechanism can be temporarily separated, and can be gradually connected, and may also rotate relative to each other during the transmission process. There cannot be a rigid connection between the driving part and the driven part of the clutch. All types of cars have clutches, just in different forms. Principle For manual transmission models, the clutch is an important component of the vehicle’s power system. It is responsible for cutting off and connecting the power to the engine. When driving on urban roads or complex road sections, the clutch has become one of our most frequently used components, and the quality of clutch use directly reflects the level of driving and also plays a role in protecting the vehicle. How to use the clutch correctly and master the principle of the clutch so that it can be used to solve problems under special circumstances is something that every driver who drives a manual transmission vehicle should master. The clutch is divided into three working states, namely non-linkage when the clutch is depressed, full linkage when the clutch is not depressed, and semi-linkage when the clutch is partially depressed. When the vehicle starts, the driver depresses the clutch, and the movement of the clutch pedal pulls the pressure plate backward, that is, the pressure plate and the friction plate are separated. At this time, the pressure plate and the flywheel are not in contact at all, and there is no relative friction. When the vehicle is running normally, the pressure plate is tightly pressed against the friction plate of the flywheel. At this time, the friction between the pressure plate and the friction plate is the largest. There is relative static friction between the input shaft and the output shaft, and the two rotate at the same speed. . The last one is the semi-linked state of the clutch, where the friction between the pressure plate and the friction plate is less than the fully linked state. At this time, there is a sliding friction state between the clutch pressure plate and the friction plate on the flywheel. The speed of the flywheel is greater than the speed of the output shaft, and part of the power transmitted from the flywheel is transmitted to the gearbox. In this state, the relationship between the engine and the driving wheels is equivalent to a soft connection state. Effect 1. Ensure the car starts smoothly This is the primary function of a clutch. Before the car starts, it is natural to start the engine. When the car starts, the car gradually accelerates from a completely stationary state. If the drive train (which connects the entire car) is rigidly connected to the engine, the car will suddenly rush forward as soon as the transmission is put into gear, but it will not start. This is because when the car goes from standstill to forward, it has a large inertia, which causes a large resistance torque to the engine. Under the action of this inertial resistance moment, the engine speed drops sharply below the minimum stable speed (generally 300-500RPM) in an instant. The engine stalls and cannot work. Of course, the car cannot start. Therefore, we need the help of the clutch. After the engine starts and before the car starts, the driver first depresses the clutch pedal to disengage the clutch to disengage the engine and transmission system, then puts the transmission into gear, and then gradually releases the clutch pedal to gradually engage the clutch. During the engagement process, the resistance torque experienced by the engine gradually increases, so the accelerator pedal should be gradually depressed at the same time, that is, the fuel supply to the engine should be gradually increased to keep the engine speed at the lowest stable speed without stalling. At the same time, as the clutch engagement gradually increases, the torque transmitted from the engine to the drive wheels through the transmission system gradually increases. When the traction force is enough to overcome the starting resistance, the car starts to move from a standstill and gradually accelerates. 2. Achieve smooth shifting During the driving process of the car, in order to adapt to the changing driving conditions, the transmission system often needs to change different gears to work. To shift gears in a gear transmission, the gears or other shifting mechanisms are generally used to push a certain gear pair of the original gear out of the transmission, and then put the gear pair of another gear into operation. Before shifting gears, the clutch pedal must be depressed to interrupt the power transmission so that the meshing pair of the original gear can be disengaged. At the same time, the speed of the meshing parts of the meshing pair of the new gear can gradually be synchronized, so that the impact when entering the mesh can be greatly reduced. reduced, resulting in smooth shifting. 3. Prevent drive system overload When the car performs emergency braking, if there is no clutch, the engine will be rigidly connected to the transmission system and its speed will decrease sharply. Therefore, all moving parts will produce a large inertia moment (the value of which may be much greater than that generated by the engine during normal operation). maximum torque), causing a load that exceeds its carrying capacity on the drive train, causing damage to the machine parts. With a clutch, this danger can be eliminated by relying on the possible relative motion between the active and driven parts of the clutch. Therefore, we need a clutch to limit the maximum torque experienced by the drive train to ensure safety.

The electronic airbag system is a passive safety protection system that works in conjunction with seat belts to provide effective anti-collision protection for the occupants. In the event of a car collision, car airbags can reduce the rate of head injuries by 25% and the rate of facial injuries by about 80%.     History The airbag was first proposed by Hetrick in August 1953 and obtained the U.S. patent for “automobile buffer safety device”. With the formulation of vehicle safety standards in various countries, the equipment rate of airbags is getting higher and higher. The airbag equipment rate in cars in Europe, the United States, Japan and other countries has reached nearly 100%. Structure It is mainly composed of airbag sensors, anti-collision airbags and electronic control devices. The driver’s side anti-collision airbag is installed in the steering wheel; the passenger’s side anti-collision airbag is usually installed on the dashboard. The airbag sensors are installed on the left, right and middle parts of the cab partition respectively; the airbag sensor and airbag system in the middle part are installed together with the electronic control device. The airbag component mainly consists of an airbag, a gas generator and an igniter. For example, the electronic control device is used for data collection and data processing, diagnosing the reliability of the airbag, ensuring that when the preset value is reached, the ignition signal is sent out in time, and the ignition is timed to ensure that the driving gas generator has a large enough driving current. wait. Principle When a car collides while driving, the airbag sensor first receives the impact signal. As long as it reaches the specified intensity, the sensor will act and send a signal to the electronic controller. After receiving the signal, the electronic controller compares it with its original stored signal. If the airbag deployment condition is met, the driving circuit sends a starting signal to the gas generator in the airbag assembly. After receiving the signal, the gas generator ignites the gas generating agent and generates a large amount of gas. After being filtered and cooled, it enters the air bag, causing the air bag to break through the liner and deploy rapidly in a very short time, forming an elastic air cushion in front of the driver or passenger. , and timely leakage, contraction, and absorption of impact energy, thereby effectively protecting the human head and chest from injury or reducing the degree of injury. Modern cars have not only added side impact airbags, but are also constantly developing and progressing in airbag fabric materials, igniters, sensor technology and other aspects. Type 1.Single air bag The standard number of airbags in domestically produced mid- to low-end cars is 1-2, usually one in the driving and co-pilot positions of the vehicle, to protect the front row members from damage to the chest and brain in the event of a violent collision with the vehicle. effective protection. 2. Side airbags Side airbags are installed on the outside of the seat to reduce injuries caused by side impacts. Many manufacturers’ models come standard with side airbags for the two front seats, but very few models are equipped with rear side airbags. 3. Knee airbag Most models are only equipped with main and passenger airbags, side airbags, etc. In fact, when a frontal collision occurs, the lower part of the vehicle should be protected more. The distance between the lower knee and the center console is the shortest and is the most vulnerable area. The site of the fracture injury. 4.Head airbag The head airbag is installed in the curved steel beam of the roof, usually running through the front and rear, and is controlled by the lateral acceleration sensor in the vehicle body. When the lateral acceleration is greater than the normal value and reaches a dangerous value, the detonation will be controlled. It has a very good personnel protection function for serious accidents such as side collisions and rollovers. Start condition In order to ensure that the airbag opens at the appropriate time, automobile manufacturers have stipulated the conditions for the detonation of the airbag. Only when these conditions are met, the airbag will explode. Although in some traffic accidents, the occupants in the car suffered severe head injuries or even life-threatening injuries, and the vehicle was close to being scrapped, the airbag will still not open if the conditions for the airbag to explode are not met. Suitable speed and impact angle are required for airbag deployment. Theoretically, the airbag can only be deployed if the vehicle hits a fixed object at a position approximately 60° to the left and right in front of the vehicle at a speed higher than 30km/h. The speed mentioned here is not the vehicle speed as we usually understand it, but the speed at which the vehicle collides with a relatively rigid fixed obstacle in the test room. In the actual collision, the air bag must be opened only when the vehicle speed is higher than the test speed. The main stress-bearing parts of a car when it collides are the bumper and body longitudinal beams. In order to buffer the impact force during a collision, most of the front parts of the car body are designed with a collision buffer zone, and the stiffness distribution of the car body is also uneven. In some accidents, such as when a car collides with a truck without rear protection devices, or a car rolls over after hitting a guardrail, or a side collision occurs, such accidents often do not involve a direct impact on the front of the car body. , mainly caused by collisions between the upper part of the vehicle body and the sides. The rigidity of the collision part of the vehicle body is very small. Although the cabin is greatly deformed, resulting in injury or death to the occupants in the vehicle, sometimes the airbag cannot be deployed due to the wrong collision location. Especially in a side collision, if the side airbags are not equipped, the main and auxiliary airbags cannot detonate because they cannot meet the detonation conditions, which can easily cause fatal injuries to the passengers. Advantage The airbag can evenly distribute the impact force on the head and chest, preventing the fragile body of the passenger from directly colliding with the vehicle body, greatly reducing the possibility of injury. Airbags can indeed effectively protect passengers in frontal collisions. Even if seat belts are not fastened, anti-collision airbags are still enough to effectively reduce injuries. According to statistics, when a car equipped with airbags encounters a frontal collision, it can reduce the degree of injury to passengers by up to 64%, and even 80% of the passengers are not wearing seat belts! As for collisions from the side and rear seats, they still depend on the function of the seat belts. In addition, the volume when the air bag explodes is only about 130 decibels, which is within the range that the human body can tolerate; 78% of the gas in the air bag is nitrogen, which is very stable, non-toxic, and harmless to the human body; the powder brought out when the air bag is exploded is to maintain the air bag The lubricating powder does not stick together in the folded state and is harmless to the human body. Defect Airbags also have their unsafe side. It is calculated that if a car is traveling at a speed of 60km/h, a sudden impact will cause the vehicle to stop within 0.2 seconds, and the airbag will pop up at a speed of approximately 300km/h, and the resulting impact force will be approximately 180kg. , which is difficult to withstand the more fragile parts of the human body such as the head and neck. Therefore, if the angle and strength of the airbag pop-up are slightly wrong, a “tragedy” may result. Improve It can be seen from the defects in the use of airbags that the basic design goal of existing airbags is to deal with serious traffic accidents. However, in some less serious accidents, the system overreacts, which may cause harm to drivers and passengers. Applying too much force will be counterproductive and cause unnecessary harm. In view of the problems existing in actual use, we hope that the airbag system can accurately sense the collision of the car before the airbag is deployed, and judge the severity of the collision according to the program. If the collision level is relatively low, only the safety Just tighten the pre-tensioning mechanism of the belt; if the collision level is relatively high and the air bag needs to be activated, the command to ignite the air bag will be transmitted to the air bag system. This means that the airbag system is required to accurately sense the collision; it can imitate the human brain and determine whether the airbag needs to be deployed based on the actual degree of collision, and it must have certain flexibility; and it must be able to respond appropriately to occupants of different body shapes. Adjust airbags.

Transmission, also known as gearbox, is a mechanism used to change the speed and torque from the engine. It can fix or change the transmission ratio of the output shaft and input shaft in fixed or stepped gears. The transmission consists of a speed change transmission mechanism and a control mechanism. Some cars also have a power output mechanism. Most of the transmission mechanisms use ordinary gear transmission, and some use planetary gear transmission. Ordinary gear transmission transmission mechanisms generally use slip gears and synchronizers.     Classification 1. Stepped transmission Stepped transmissions are the most widely used. It adopts gear transmission and has several fixed transmission ratios. Depending on the type of gear train used, there are two types of axis-fixed transmissions (ordinary transmissions) and axis-rotating transmissions (planetary gear transmissions). The transmission ratio of transmissions for cars and light and medium trucks usually has 3-5 forward gears and one reverse gear. In combined transmissions for heavy trucks, there are more gears. The so-called transmission gear number refers to the number of forward gears. 2.Continuously variable transmission Continuously variable transmission refers to a transmission system that can continuously obtain any transmission ratio within the transmission range. Continuously variable transmission can achieve the best match between the drive train and engine operating conditions. Common continuously variable transmissions include hydromechanical continuously variable transmissions and metal belt continuously variable transmissions (VDT-CVT). 3. Integrated transmission Integrated transmission refers to a hydromechanical transmission composed of a hydraulic torque converter and a gear-type stepped transmission. Its transmission ratio can be continuously changed within several discontinuous ranges between the maximum value and the minimum value. Currently, There are many applications. Function 1.Change the transmission ratio Meet the traction requirements of different driving conditions, make the engine work under favorable working conditions as much as possible, and meet possible driving speed requirements. Change the speed of the car and the torque on the driving wheels of the car within a wide range. Due to different driving conditions of the car, the driving speed and driving torque of the car are required to change within a wide range. For example, the vehicle speed on the highway should be able to reach 100km/h, while in urban areas, the vehicle speed is often around 50km/h. When an empty vehicle is driving on a straight road, the driving resistance is very small, but when it is fully loaded and going uphill, the driving resistance is very large. The characteristic of automobile engines is that the speed change range is small, and the torque change range cannot meet the needs of actual road conditions. 2. Realize reverse driving Used to meet the needs of the car driving in reverse. To achieve reverse driving of a car, the engine crankshaft generally can only rotate in one direction, and the car sometimes needs to be able to drive backwards. Therefore, the reverse gear set in the gearbox is often used to realize the reverse driving of the car. 3. Interrupt power transmission When the engine starts, idles, shifts gears, or needs to be stopped for power output, the power transmission to the drive wheels is interrupted. 4. Achieve gaps When the clutch is engaged, the transmission may not output power. For example, it can be ensured that the driver releases the clutch pedal and leaves the driver’s seat without stalling the engine. Constitute The gearbox consists of two parts: a speed change transmission mechanism and a speed change control mechanism. The main function of the speed change transmission mechanism is to change the value and direction of torque and rotational speed; the main function of the control mechanism is to control the transmission mechanism to realize the transformation of the transmission ratio, that is, to achieve gear shifting, in order to achieve variable speed and torque. Structure The simple transmission has the advantages of high efficiency, simple structure and easy use, but it has few gears and a small i change range (small traction and speed range), so it should only be used by some lathes with a small number of gears. If the range of i is increased, the size of the transmission will be increased and the shaft span will be increased. In order to increase the number of gears without making the shaft span too large, a component transmission can be used. The so-called component transmission is usually composed of two simple transmissions. The one with more gears is called the main transmission, and the one with fewer gears is called the auxiliary transmission. Principle The mechanical gearbox mainly applies the speed reduction principle of gear transmission. Simply put, there are multiple sets of gear pairs with different transmission ratios in the gearbox, and the gear shifting behavior when the car is driving is to make different gear pairs in the gearbox work through the operating mechanism. For example, at low speed, let the gear pair with a large transmission ratio work, and at high speed, let the gear pair with a small transmission ratio work.

The spark plug is an important component of the gasoline engine ignition system. It can introduce high-voltage electricity into the combustion chamber and cause it to jump across the electrode gap to generate sparks, thereby igniting the combustible mixture in the cylinder. It is mainly composed of wiring nut, insulator, wiring screw, center electrode, side electrode and shell. The side electrode is welded on the shell.     Introduction The spark plug, commonly known as the burner, is used to discharge the pulsed high-voltage electricity sent from the high-voltage wire (burner wire), breakdown the air between the two electrodes of the spark plug, and generate electric sparks to ignite the mixed gas in the cylinder. The main types are: quasi-type spark plugs, rim-protruding spark plugs, electrode-type spark plugs, seat-type spark plugs, pole-type spark plugs, surface-flash type spark plugs, etc. The spark plug is installed on the side or top of the engine. The early spark plug was connected to the distributor by the cylinder wire. In the past ten years or so, the engines on cars have basically been changed to the ignition coil directly connected to the spark plug. The working voltage of the spark plug is at least 10,000V. The high-voltage electricity is generated by the ignition coil from 12V electricity and then passed to the spark plug. Structure 1. Steel shell: The lower part of the steel shell is a fine thread, which is used to assemble with the spark plug hole in the cylinder head. The upper part has an external hexagonal nut, which is used to install the spark plug sleeve to tighten or screw out the spark plug. 2. The metal rod is the center electrode. The lower end of the metal rod is in contact with the upper end of the center electrode through the conductor glass body, and the upper end of the metal rod is equipped with a wiring nut. 3. There is a high alumina ceramic insulator between the steel shell and the center electrode to insulate the center electrode when electricity is energized. 4. The lowermost part of the steel shell is equipped with curved side electrodes. 5. There is a copper gasket in the middle of the outside of the steel shell. Principle Under the action of high voltage, the air between the center electrode and the side electrode of the spark plug will quickly ionize, forming positively charged ions and negatively charged free electrons. When the voltage between the electrodes reaches a certain value, the number of ions and electrons in the gas increases like an avalanche, causing the air to lose its insulation, and the gap forms a discharge channel, causing a “breakdown” phenomenon. At this point, the gas forms a luminous body, a “spark”. As it expands due to heat, a “pop” sound also occurs. The temperature of this kind of electric spark can be as high as 2000~3000℃, which is enough to ignite the mixture in the cylinder combustion chamber. Characteristic In spark plug standards, calorific value is usually used to characterize the thermal characteristics of the spark plug. The calorific value of the spark plug represents the balance ability of the spark plug insulator skirt to absorb and dissipate heat. The higher the calorific value. The stronger the balance between heat absorption and heat dissipation, the hot spark plug has a lower calorific value and the cold spark plug has a higher calorific value. Generally, engines with high power and large compression ratio use cold spark plugs with high calorific value; on the contrary, engines with low power and small compression ratio use hot spark plugs with low calorific value. Generally, the selection of spark plugs is determined by the factory through product shaping experiments and should not be replaced at will [7]. Develop With the development of the automobile industry, the performance of spark plugs is also constantly improved to improve the working quality of gasoline engines. For example, to improve the exhaust purification effect, wide gap spark plugs (gap 1.0~1.2mm) are used; to limit the noise of automobile radio waves , developed anti-interference spark plugs, etc. In the past, the service life of spark plugs was very short. Automobile manufacturers stipulated that spark plugs must be inspected or replaced after the car has traveled 3,000km (or 6 months). With the improvement of spark plugs and related ignition devices, coupled with some measures for exhaust purification, the service life of spark plugs has been greatly improved. It is generally stipulated that the spark plug must be inspected or replaced after the car has traveled 10,000km (or every one year). Spark plugs with platinum electrodes have a longer service life and generally do not need to be inspected and replaced within 100,000km of driving.

Car bumpers are safety devices that absorb and slow down external impact forces and protect the front and rear of the car body. Many years ago, the front and rear bumpers of automobiles were stamped from steel plates into channel steel and riveted or welded to the frame longitudinal beams. There was a large gap between the car body and the car body, which looked very unsightly.     With the development of the automobile industry and the extensive application of engineering plastics in the automobile industry, automobile bumpers, as an important safety device, are also on the road to innovation. In addition to maintaining their original protective functions, today’s front and rear bumpers of cars must also pursue harmony and unity with the body shape and pursue lightweighting. The front and rear bumpers of cars are made of plastic, which are called plastic bumpers. Generally, the plastic bumper of a car is composed of three parts: outer panel, buffer material and cross beam. The outer plate and buffer material are made of plastic, and the cross beam is stamped with cold-rolled sheet to form a U-shaped groove; the outer plate and buffer material are attached to the cross beam. Introduce 20 years ago, the front and rear bumpers of cars were mainly made of metal materials. They were stamped into U-shaped channel steel from steel plates with a thickness of more than 3 mm. The surface was treated with chrome plating. They were riveted or welded to the frame longitudinal beams and had a relatively long section with the body. The large gap seems to be an additional component. With the development of the automobile industry, automobile bumpers, as an important safety device, are also on the road to innovation. In addition to maintaining their original protective functions, today’s front and rear bumpers of cars must also pursue harmony and unity with the body shape and pursue lightweighting. In order to achieve this purpose, the front and rear bumpers of cars are made of plastic, which are called plastic bumpers. Effect Car bumpers (anti-collision beams), located in most areas of the front and rear of the car, are ostensibly designed to avoid the impact of external damage to the vehicle’s safety system. They have the ability to reduce injuries to drivers and passengers in high-speed collisions. More and more are now being designed for pedestrian protection. Protect 1. Use the corner indicator column to determine the position of the bumper The marks erected at the corners of the bumper are indicator posts. Some companies’ products also have the type that automatically expands and contracts with motor drive. This kind of corner indicator column can accurately confirm the corner position of the bumper, prevent damage to the bumper, and improve driving skills. People who often scratch the bumper are best to install one and give it a try. With this corner marking column, you can correctly judge the position of the bumper from the driver’s seat, which is very convenient. 2. Installing corner rubber can reduce bumper damage The corners of the bumper are the most easily injured part of the car shell. People who are not good at driving can easily scratch the corners and make them full of scars. What protects this part is the corner rubber. It only needs to be attached to the corner of the bumper, and the installation is very simple. This method can reduce the degree of damage to the bumper. Of course, if the rubber is bruised, just replace it with a new one. In addition, corner rubber is a very thick rubber pad that is attached to the corner of the bumper. If you want it to look integrated with the car body, you can spray paint on it.

The wiper is an important accessory installed on the windshield. Its function is to remove rain, snow and dust on the windshield that obstructs the view. Therefore, it plays an important role in driving safety.     Overview Wipers generally include vacuum wipers, electric wipers and wipers with electronic control units. The disadvantage of vacuum wipers is that the movement speed of the wiper blade is unstable. When the vacuum degree of the engine is reduced (for example, when the car is climbing a hill), the wiper blade will stop, blurring the driver’s vision. Vacuum wipers were phased out in 1972, replaced by electric wipers. Structure The electric windshield wiper is driven by a motor and generally consists of a wiper arm, wiper blade assembly, rubber brush blade, brush blade support, brush blade holder, wiper arm spindle, wiper base plate, and motor , deceleration mechanism, drive rod system, drive rod hinge, wiper switch and wiper switch knob. Of course, wipers with a wiper ECU are also equipped with an electronic control unit ECU. The electric windshield wiper is driven by an electric motor. The left and right wiper blades of the wiper are pressed against the outer surface of the windshield glass by the wiper brush arms. The electric motor drives the reduction mechanism to rotate and makes reciprocating motion through the drive rod system. Drive the wiper arm and wiper blade to swing left and right to wipe the windshield. Principle The electric motor on the electric wiper drives the output shaft through the worm gear on the armature shaft and drives the output gear through the idler gear and idler shaft. The output shaft then operates the output arm connected to the wiper linkage. When the motor rotates, the output arm and connecting rod are driven to move forward and backward. A resistor located on the control switch is connected to the motor’s armature winding to control the speed of the motor. The driver can flip the switch as needed to cause current to flow into the motor’s input circuit.

The automobile engine is the device that provides power for the automobile. It is the heart of the automobile and determines the power, economy, stability and environmental protection of the automobile. According to different power sources, automobile engines can be divided into diesel engines, gasoline engines, electric vehicle motors and hybrids.     Common gasoline engines and diesel engines are reciprocating piston internal combustion engines, which convert the chemical energy of the fuel into the mechanical energy of piston movement and output power to the outside. The gasoline engine has high speed, low mass, low noise, easy starting, and low manufacturing cost; the diesel engine has a large compression ratio, high thermal efficiency, and better economic performance and emission performance than the gasoline engine. History development The engine is the power source of the car. Most automobile engines are thermal energy power devices, referred to as heat engines. Thermal engine converts the thermal energy generated by fuel combustion into mechanical energy by means of the state change of the working fluid. In 1876, the German Nicolaus A. Otto invented the reciprocating piston four-stroke gasoline engine based on the atmospheric pressure engine. Due to the use of four strokes of intake, compression, power and exhaust, the thermal efficiency of the engine is increased from 11% of the atmospheric pressure engine to 14%, while the mass of the engine is reduced by 70%. In 1892, German engineer Rudolf Diesel invented the compression-ignition engine (diesel engine), achieving the second major breakthrough in the history of internal combustion engines. Due to the high compression ratio and expansion ratio, the thermal efficiency was doubled compared to other engines at the time. In 1926, Swiss A. Buchi proposed the theory of exhaust gas turbocharging, which uses the energy of exhaust gas discharged from the engine to drive the compressor and supercharge the engine. After the 1950s, exhaust gas turbocharging technology began to be gradually applied to vehicle internal combustion engines, greatly improving engine performance and becoming the third major breakthrough in the history of internal combustion engine development. In 1956, the German Wankel invented the rotary engine, which greatly increased the engine speed. In 1964, the German NSU company installed a rotary engine on a car for the first time. In 1967, the German company Bosch introduced the electronic fuel injection system (Electronic Fuel Injection, EFI) controlled by an electronic computer for the first time, creating a history of the application of electronic control technology in automobile engines. After 30 years of development, the engine management system (Engine Management System, EMS) with electronic computers as the core has gradually become a standard configuration on automobiles (especially car engines). Due to the application of electronic control technology, the engine’s pollutant emissions, noise and fuel consumption have been greatly reduced, and its power performance has been improved. This has become the fourth major breakthrough in the history of internal combustion engine development. In 1967, the United States held a public demonstration of hydrogen car driving. The hydrogen car could run 121 kilometers in 10 minutes at a speed of 80 kilometers per hour. The car has 19 seats and is manufactured by the American Billings Company. In 1971, the first bus equipped with a Stirling engine started running. In 1972, Japan’s Honda Motor sold the Civic sedan equipped with a Compound Vertex Controlled Combustion (CVCC) engine on the market, marking the first launch of a lean gas combustion engine. In 1977, the first international electric vehicle conference was held in Chicago, USA. During the conference, more than 100 electric vehicles of various types were on display. In 1978, Japan successfully researched hybrid vehicles. In August 1979, Brazil produced an alcohol-fueled car. Brazil is the country with the largest number of alcohol-based cars in the world. In 1980, Japan successfully developed a liquid hydrogen vehicle. A special storage tank is installed at the rear to keep liquid hydrogen at a low temperature and at a certain pressure. The car used 85 liters of liquid hydrogen and traveled 400 kilometers at a speed of 135 kilometers per hour. In 1980, the United States successfully trial-produced a zinc-chlorine battery electric vehicle. In 1980, Spain successfully developed a solar car. In 1980, an engineer in Itzehoe, northwest of Hamburg, West Germany, invented a car powered by calcium carbide gas (acetylene gas). First turn calcium carbide into gas, and then use this gas to burn to propel a jet engine to drive a car. Its speed and safety are no less than that of a gasoline car. 20 kilograms of calcium carbide can enable the car to travel at least 300 kilometers. In 1980, John Cooper and Erwin Beren of the University of California began to study “burned aluminum” electric vehicles. In 1983, the world’s first car equipped with a diesel ceramic engine successfully ran tests. The engine installed was developed by Japan’s Kyoto Ceramics Company. Its main components are made of ceramics, eliminating the need for a cooling system. It is light in weight and has significant energy saving effects. It can travel 30% longer than a conventional engine under the same conditions. In 1984, the former Soviet Union developed a dual-fuel vehicle. When the car is started, it uses gasoline first and then natural gas. In 1984, Amocoby Chemical Company of Mobil Oil Company of the United States developed a synthetic material called Dulon plastic. The company used this plastic to successfully create the world’s first all-plastic automobile engine. The weight is only 84 kg. The American Lora T-616GT car uses this all-plastic engine. In 1984, Australian engineer Shalish successfully developed an OCP engine. In 1985, Australia’s Pilandin developed a steam engine car that was safe, reliable, flexible to start, high-speed and smoke-free. In 1986, Japan’s Sanyo Electric Company successfully developed the first solar cell car. In 1994, David Byrne of the United Kingdom invented another wind-powered car and has put it into mass production. Structure The engine is composed of two major mechanisms, the crank connecting rod mechanism and the valve mechanism, as well as five major systems including cooling, lubrication, ignition, fuel supply, and starting system. The main components include cylinder block, cylinder head, piston, piston pin, connecting rod, crankshaft, flywheel, etc. The working chamber of a reciprocating piston internal combustion engine is called a cylinder, and the inner surface of the cylinder is cylindrical. The piston that reciprocates in the cylinder is hinged to one end of the connecting rod through the piston pin, and the other end of the connecting rod is connected to the crankshaft. The crankshaft is supported by the bearing on the cylinder block and can rotate within the bearing to form a crank-connecting rod mechanism. When the piston reciprocates in the cylinder, the connecting rod drives the crankshaft to rotate. On the contrary, when the crankshaft rotates, the connecting rod journal makes a circular motion in the crankcase, and drives the piston up and down in the cylinder through the connecting rod. Every time the crankshaft rotates once, the piston moves up and down once, and the volume of the cylinder continuously changes from small to large, then from large to small, and the cycle continues. The top of the cylinder is closed with a cylinder head. The cylinder head is equipped with intake valves and exhaust valves. By opening and closing the intake and exhaust valves, the air is filled into the cylinder and the air is exhausted out of the cylinder. The opening and closing of the intake and exhaust valves are driven by the camshaft. The camshaft is driven by the crankshaft through a toothed belt or gear.