How to Appreciate Cars? The performance of a car? I am a rookie

I. The main structural parameters and performance parameters of the car

The main features and technical characteristics of the car with the type of engine installed and the characteristics of the different, usually have the following structural parameters and performance parameters.

1. The mass of the whole car equipment (kg): the mass of the car fully equipped, including the mass of all devices such as lubricating oil, fuel, accompanying tools, spare tires and so on.

2. Maximum gross mass (kg): the total mass of the car when fully loaded.

3. Maximum loaded mass (kg): the maximum loaded mass of the car when traveling on the road.

4. Maximum axle mass (kg): the maximum total mass carried by a single axle of the car. It is related to roadworthiness.

5. Length (mm): the distance between the two extremes of the length of the car.

6. Width (mm): the distance between the two extremes of the width direction of the car.

7. Height (mm): the distance between the highest point of the car and the ground.

8. Wheelbase (mm): the distance from the center of the front axle to the center of the rear axle.

9. Wheelbase (mm): the distance between the center line of the tread of the left and right tires of the same car.

10. Front overhang (mm): the distance from the front of the car to the center of the front axle.

11. Rear overhang (mm): the distance from the last end of the car to the center of the rear axle.

12. Minimum Ground Clearance (mm): the distance from the lowest point to the ground when the car is fully loaded.

13. Approach angle (°): the front end of the car protruding point of the tangent to the front wheel and the ground angle.

14. Angle of Departure (°): the angle between the tangent line drawn from the rear protruding point to the rear wheels and the ground.

15. Turning radius (mm): when the car steering, the center plane of the outer steering wheel in the vehicle support surface of the track circle radius. The turning radius when the steering wheel is turned to the limit position is the minimum turning radius.

16. Maximum speed (km/h): the maximum speed that can be achieved when the car is traveling on a straight road.

17. Maximum gradient (%): the maximum climbing ability of the car when fully loaded.

18. Average Fuel Consumption (L/100km): the average fuel consumption per 100km when the car is traveling on the road.

19. The number of wheels and the number of driving wheels (n × m): the number of wheels to the number of wheels as the basis for measurement, n represents the total number of wheels of the car, m represents the number of driving wheels. The basic parameters of the automobile engine include the number of engine cylinders, cylinder arrangement, valves, displacement, maximum output power, maximum torque.

20, the number of cylinders: the number of cylinders commonly used in automobile engines are 3, 4, 5, 6, 8 cylinders. Displacement of 1 liter of the following engine commonly used 3-cylinder, 1 - 2.5 liters is generally 4-cylinder engine, 3 liters of the engine is generally 6-cylinder, 4 liters of 8-cylinder, 5.5 liters or more with 12-cylinder engine. Generally speaking, under the same cylinder bore, the more the number of cylinders, the larger the displacement, the higher the power; under the same displacement, the more the number of cylinders, the smaller the bore, the speed can be increased, so as to obtain a larger boost power.

21, the cylinder arrangement: general 5-cylinder engine cylinders are arranged in an in-line manner, a few 6-cylinder engine also has an in-line manner. In-line engine cylinder block into a word lined up, the cylinder, cylinder head and crankshaft structure is simple, low manufacturing cost, good low-speed torque characteristics, fuel consumption, compact size, more widely used, the disadvantage is that the power is lower. The dynamic balance of the inline 6-cylinder is better, and the vibration is relatively small. Most 6 to 12-cylinder engine using V-shaped arrangement, V-shaped that is, the cylinders are arranged in four staggered angles, compact shape, V-shaped engine length and height dimensions are small, the arrangement is very convenient.V8 engine structure is very complex, manufacturing costs are very high, so the use of fewer, V12 engine is too large and too heavy, only a very few premium sedans used.

22, the number of valves: most domestic engines use 2 valves per cylinder, i.e., an intake valve, an exhaust valve; foreign car engines generally use 4 valves per cylinder structure, i.e., 2 intake valves, 2 exhaust valves, to improve the efficiency of the intake and exhaust; some foreign companies began to use a 5-valve structure per cylinder, i.e., 3 intake valves, 2 exhaust valves, the main role of the increase in the intake volume, so that combustion The main function is to increase the volume of air intake, so that the combustion is more thorough. The number of valves is not the more the better, 5-valve can indeed improve the efficiency of the intake, but the structure is extremely complex, processing difficulties, the use of less, the domestic production of the new Jetta King on the use of five-valve engine.

23, exhaust: cylinder working volume refers to the piston from the upper stop to the lower stop swept by the volume of gas, also known as single-cylinder displacement, which depends on the bore and piston stroke. Engine displacement is the sum of the working volume of each cylinder, generally used (L) to express. Engine displacement is one of the most important structural parameters, it is more representative of the size of the engine than the bore and the number of cylinders, many indicators of the engine are closely related to the exhaust.

24, the highest output power: the highest output power is generally used horse (PS) or kilowatts (KW) to indicate. Engine output power with the rotational speed of the relationship is very large, with the increase in speed, the engine's power is also correspondingly increased, but after a certain speed, the power instead of a downward trend. Generally in the car instructions in the highest output power at the same time the speed per minute to say (r/min), such as 100PS / 5000r/min, that is, at 5000 revolutions per minute, the highest 25, output power of 100 horsepower.

Maximum torque: the engine from the crankshaft end of the torque output, torque is expressed as N.m / r / min, the maximum torque generally appear in the engine in the range of medium and low speed, with the speed of the torque instead of decreasing. Of course, in the choice at the same time to weigh how to rationalize the use, not to waste the existing function. For example, Beijing winter and summer are necessary to open the air conditioning, in the choice of engine power should be taken into account not too small; just in the city ring road commuting traffic car, there is no need to pick over the high-powered engine. Try to do economic, reasonable selection of the engine.

Second, the basic engine parameters

1, the number of cylinders: the number of commonly used automotive engine cylinders are 3, 4, 5, 6, 8, 10, 12 cylinders. Displacement of 1 liter of engine commonly used three-cylinder, 1 ~ 2.5 liters is generally four-cylinder engine, 3 liters of engine is generally 6 cylinders, 4 liters of 8 cylinders, 5.5 liters of more than 12-cylinder engine. Generally speaking, under the same cylinder bore, the more cylinders, the larger the displacement, the higher the power; under the same displacement, the more cylinders, the smaller the bore, the speed can be increased, so as to obtain a larger boost power.

2, the cylinder arrangement: general 5-cylinder engine cylinders are arranged in an in-line manner, a few 6-cylinder engine also has an in-line manner, in the past there has been an in-line 8-cylinder engine. Inline engine cylinder block into a word lined up, cylinder, cylinder head and crankshaft structure is simple, low manufacturing costs, low-speed torque characteristics, fuel consumption, compact size, more widely used, the disadvantage is that the power is lower. General 1 liter or less of gasoline engines are mostly 3-cylinder inline 1 ~ 2.5 liter gasoline engines are mostly 4-cylinder inline, some four-wheel drive vehicles with inline 6-cylinder, because of its width is small, can be in the slandered side of the arrangement of the supercharger and other facilities. The dynamic balance of the inline 6 cylinder is better and the vibration is relatively small, so it is also used for some medium and high pole cars, such as the old Shanghai car.

6~12 cylinder engines generally use V-shaped arrangement, of which the V10 engine is mainly installed in the racing car. v-shaped engine length and height dimensions are small, the arrangement is very convenient, and generally believe that the v-shaped engine is a more advanced engine, but also become one of the symbols of the level of the sedan. v8 engine is very complex structure, manufacturing cost is very high, so the use of the lesser, v12 engine is too large and heavy, only a very small amount of engine. Too big and too heavy, only a very few senior sedan used. Volkswagen recently developed a W-type engine, there are two kinds of W8 and W12, that is, the cylinders are arranged in four rows of staggered angles, the shape of a compact body.

2, the number of valves: most domestic engines use 2 valves per cylinder, i.e., an intake valve, an exhaust valve; foreign sedan engines generally use a 4-valve structure per cylinder, i.e., 2 intake valves, 2 exhaust valves, improve the efficiency of the intake and exhaust; some foreign companies are beginning to use a 5-valve structure per cylinder, i.e., 3 intake valves, 2 exhaust valves, the main role is to increase the amount of intake air to make the combustion The main function is to increase the volume of air intake, so that the combustion is more thorough. The number of valves is not the more the better, 5-valve can indeed improve the efficiency of the intake, but the structure is extremely complex, processing difficulties, the use of less, the domestic production of the new Jetta King on the use of five-valve engine.

Exhaust: cylinder working volume is the volume of gas swept by the piston from the upper stop to the lower stop, also known as single-cylinder displacement, which depends on the cylinder bore and piston stroke. Engine displacement is the sum of the working volume of each cylinder, generally used (L) to express.

3, engine displacement is one of the most important structural parameters, it is more representative of the size of the engine than the bore and the number of cylinders, many indicators of the engine are closely related to the exhaust. For cars, displacement is only a relatively important technical parameters, it shows the car's general power, equipment and price level, but in China car engine displacement has other significance.

4, the highest output power: the highest output power is generally expressed in horse (PS) or kilowatts (KW). Engine output power with the rotational speed relationship is very large, with the increase in speed, the engine power is also correspondingly increased, but after a certain speed, the power instead of a downward trend. Generally in the car instructions in the highest output power at the same time the speed per minute to indicate (r/min), such as 100PS/5000r/min, that is, at 5000 revolutions per minute when the highest output power 100 horsepower.

5, maximum torque: the engine from the crankshaft end of the torque output, torque is expressed as N.m/r/min, the maximum torque is generally found in the engine in the range of medium and low speed, with the speed of the torque instead of decreasing.

Three, what is the "Euro I" and "Euro II" standards

In recent years, automobile emissions comply with emission standards has become one of the hot topics of concern. Since September 1, 2001, the state banned the production and sale of carburetor cars, more hot topics to heat up. When it comes to emission standards, in the relevant provisions and articles often appear in the "Euro I", "Euro II" standard reference, then what is "Euro I", What is "Euro I" and "Euro II" standards?

According to the relevant information, "Euro I", "Euro II" is the European I standard and the European II standard for short. The European standard belongs to a specialized technical category, it is the European Economic ****Commonwealth Committee 91/441/EEC developed a unified directive, covering different types of automobile emissions regulations.

Now take the design of the number of passengers does not exceed 6 (including the driver), the total mass of not more than 2.5 tons of cars, for example, in January 1, 1999 to December 31, 2003 period, must meet the emission limit values are: carbon monoxide does not exceed 3.16 g / km, hydrocarbons do not exceed 1.13 g / km; in addition, diesel vehicles emissions do not exceed 0.18 g/km, with a durability of 50,000 kilometers. This is the relevant provision in the European I standard. After January 1, 2004, these gasoline vehicles are required to emit no more than 2.2 grams of carbon monoxide / km, hydrocarbons do not exceed 0.5 grams / km; diesel vehicles emit no more than 1.0 grams of carbon monoxide / km, hydrocarbons do not exceed 0.7 grams / km, particulate matter does not exceed 0.08 grams / km. This is the relevant provisions of the European II standards.

Four, multi-gate engine

January 29, 1886, the German Karl? Benz will develop their own four-stroke single-cylinder fuel engine mounted on a three-wheeled car and get a patent, the world from this day onwards really have a car. It can be said that the engine created the car. The basic structure of the engine (as shown) is composed of cylinder 1, piston 2, connecting rod 3, crankshaft 4 and other major components, each cylinder has at least two valves, an intake valve (blue) and an exhaust valve (orange).

The valve unit is an integral part of the engine's gas distribution mechanism, which plays a very important role in engine operation. The operation of a fuel engine consists of four processes: intake, compression, work and exhaust. To make the engine continuous operation must make these four processes week after week, the order of the cycle of work at regular intervals.

Two of these processes, intake and exhaust processes, need to rely on the engine's air distribution mechanism in accordance with the exact order of the cylinder delivery of combustible mixture (gasoline engines) or fresh air (diesel engines), as well as exhaust combustion after the exhaust. The other two processes, compression and work process, it is necessary to isolate the cylinder combustion chamber and the outside world into the exhaust channel, do not let the gas leakage to ensure that the engine works properly. Responsible for the above work is the valve in the gas distribution mechanism. It is like a person's respiratory organs, inhaling and exhaling, it is indispensable. With the development of technology, automobile engine speed has become higher and higher, modern car engine speed generally up to 5500 revolutions per minute or more, to complete the four work processes only 0.005 seconds, the traditional two-valve has not been able to handle in such a short period of time to complete the work of the gas exchange, which restricts the improvement of engine performance. The solution to this problem can only be to expand the space for the gas to enter and exit. In other words, trading space for time. Multi-valve technology is the best way to solve the problem, until the 80s to promote multi-valve technology to make the overall quality of the engine has a qualitative leap.

Multi-valve engine refers to the number of valves in each cylinder more than two, namely, two intake valves and an exhaust valve three-valve type; two intake valves and two exhaust valves four-valve type; three intake valves and two exhaust valves five-valve type. Most of the current multi-valve engines in sedans are four-valve. Four-cylinder engine has 16 valves, 6-cylinder engine has 24 valves, 8-cylinder engine has 32 valves. For example, the Japanese Lexus LS400 sedan engine is 8 cylinders and 32 valves. Increase the number of valves to increase the corresponding gas distribution mechanism device, the construction is more complex, generally by two overhead camshaft to control the cylinder combustion chamber arranged on both sides of the center line of the valve. Valve arrangement in the cylinder combustion chamber on both sides of the center of the inclined position, is to maximize the diameter of the valve head, increase the airflow through the area, improve the performance of gas exchange, the formation of a spark plug is located in the center of the compact combustion chamber, is conducive to the rapid combustion of the mixture.

Some people have questioned why you can't see an engine with more than 6 valves in a cylinder, given how good the valves are. Thermodynamics has a concept called "curtain area", refers to the valve circumference multiplied by the valve lift, that is, the valve opening space. The larger the "curtain area", the larger the valve opening space, the larger the air intake. Audi 100 sedan engine, for example, its four-valve "curtain area" value than the two-valve "curtain area" value, in the intake state to be half as big as in the exhaust state to be seventy percent bigger. Of course, every thing has its certain scope of application, not that the more valves "curtain area" value is the greater, according to expert calculations when each cylinder valve to increase to six, "curtain area" value but will fall, and the more valves the more complex organizations, the cost of The greater the cost. Therefore, the current car multi-valve fuel engine valve number of each cylinder are three to five, of which four valves are the most common.

The gasoline engine, for example, multi-valve engine and the traditional two-valve engine comparison, the former can absorb more air to mix the fuel combustion work, fuel savings, faster exhaust, less emission pollution, can increase engine power and reduce noise advantages, in line with the optimization of the environment and energy saving development direction, so multi-valve technology can be rapidly promoted.

With the continuous improvement of technology, this technical defect of multi-valve gas engine has been gradually overcome. Now, almost all of the world's medium and high-grade cars are equipped with multi-valve fuel engines.

Five, new car break-in

There has been too much talk about new car break-in! Whether you have a car or not, as long as you pay attention to the car, you know that new cars have a break-in phase. For this new car break-in, many people do not understand what exactly in the break-in, there are many people think that as long as the relative motion of the parts have a break-in process, and more people unnecessarily add a lot of new car break-in precautions. As a result, many people are either overly cautious during this break-in period, or unconsciously violate the break-in requirements while paying attention. Here, we'll discuss: what exactly is a new car breaking in? In addition to the normal use and maintenance of the break-in stage, what other matters need special attention?

The initial period when a new car is put into use is known as the break-in period of the car. Each manufacturer recommends a break-in period of 1,000-2,000 kilometers, or 2,000-3,000 kilometers for some models.

During this break-in period, it is natural to assume that moving parts such as the shafts and bearings in the engine, the gearbox, the clutch, the brake assembly and the driveshaft all need to be broken in, which is obviously not "wrong", but it is not "right" either, because the "break-in" between these parts is a very important part of the process. Parts and components between the "grinding" is certain, and "together" really can not talk about. According to the current mechanical design, processing technology and assembly technology, these parts have no need to go through the "grinding" in order to make them work better together and work. So, in the end, what is grinding? In this case, it's the fit between the piston rings and the cylinder walls inside the engine!

In the engine. Due to the temperature and pressure in the cylinder are very high, high-speed movement of the piston is not possible by direct contact with the cylinder wall to play a sealing role, there is a movable gap between the two, and the realization of the seal is ensured by the piston ring. Piston rings are usually composed of gas rings and oil rings, as the name suggests, the gas ring is used to seal the gas (to prevent the cylinder mixture or exhaust gas into the crankcase, so as not to reduce engine power, and to prevent contamination of the oil), the oil ring is used to seal the oil (because the crankshaft will be the crankcase of the oil thrown to the cylinder wall, the oil ring is to scrape off the role of these oil. It does not allow the oil to enter the combustion chamber and cause oil burning).

From the above introduction, it is important to note two key points: 1) the engine needs piston rings to build up cylinder pressure during operation; 2) the piston rings are the key component for break-in. Therefore, the piston ring, whether in the "break-in" period, or later in the "wear" period, it must seal the gap between the cylinder wall and the piston, so that the outer diameter of the piston ring needs to be slightly larger than the cylinder diameter, and the role of the openings are not only to facilitate the assembly, but also to be able to The purpose of the openings is both to facilitate assembly and to automatically fine-tune the diameter as it wears. In new engines, assembled together in different diameters of the piston ring and cylinder, there will be a slight difference in roundness, coupled with the respective dimensions of the machining error, so that the contact surface of the two produce a gap. For high-pressure cylinders, the impact of this gap is really not small!

New car factory, the engine's piston ring and cylinder wall have not been through the grinding, the contact surface there is a gap, so that the pressure in the cylinder does not meet the design requirements, affecting the fuel combustion, the engine may be insufficient power, work poorly; after a few thousand kilometers of the grinding, the piston ring and the cylinder wall gradually have an excellent match, so that the cylinder pressure to reach the design value, the engine into the best work! The engine enters the best working condition. This is why some people say: after the break-in period, the engine feels better in general and fuel consumption improves! It is from the same reasoning that there is a break-in period for engines after overhaul.

How to correctly use and maintain the vehicle, which has a lot of content, driving most people know, such as: generally do not overload; do not trailer or towing other vehicles or equipment; according to the user's instructions to select the specified specification of the fuel and the specified type of oil; often check the gear oil (or automatic transmission fluid), brake fluid, directional fluid, clutch booster, antifreeze, etc., and replace as required. Check the condition of gear oil (or automatic transmission fluid), brake fluid, steering fluid, clutch fluid, antifreeze, etc. and replace (or add) them according to the regulations; check the air pressure of the tires; and pay attention to the fastening of each part. Engine oil replacement time, the public break-in stage will be slightly different, because the cylinder seal is not very good, the unburned gas mixture and combustion exhaust gas may enter the crankcase. Thus, the oil deterioration is accelerated, so the first - the oil change may wish to be earlier.

According to the introduction of break-in above, there are two precautions that are directly related to break-in:

1. Avoid high speed

Out of the thin slice of ring-like piston ring and cylinder wall contact with the gap, the actual contact is only a part of the zone and point. In the break-in, the engine too high speed naturally increases the possibility of pulling hair, pulling the cylinder enough and damage to the piston ring, so the general manufacturer will recommend that the new car speed limit of 80-90 kilometers / hour. In 80-90 kilometers / hour speed band, whether foot manual gear cars or automatic cars, in accordance with the normal shift requirements into the automatic speed switching point, the engine speed in this speed band in 2500 rpm or so, the highest will not exceed 3000 rpm. This is exactly the key and the essence of the speed limit: limit the speed is actually limiting the engine speed! "Do not artificially increase the engine speed during the break-in period", this point, I hope that some newbies pay attention to. Some people think that "as long as the speed does not exceed the recommended speed limit, it does not matter if the engine is running at high speed", which in fact is exactly contrary to the speed limit recommendations.

At the same time, "hanging high gears at low speeds" is also very taboo, due to the lack of power caused by frequent frustration as well as the possibility of pulling hair, pulling the cylinder wall and damage to the piston ring. Also, don't stay at a certain speed for a long time, whether it's high or low. By the way, a word about shifting gears, although that's not part of the break-in. Shift to the car speed for difficult, not the engine speed, to "20km / h shift second gear, 40km / h shift third gear, 60km / h shift fourth gear, 70km / h shift fifth gear" for the best, the corresponding speed band are each gear his best design efficiency. "Low-speed hanging high-grade fuel saving" is not correct, because you can not go to save fuel in the case of possible damage to the engine, otherwise. Save gasoline money is not enough to compensate for the loss of engine working conditions caused by the shortened service life.

2. Driving gently

In the break-in stage, the requirement of driving gently is good for all moving parts, especially for the cylinder in the break-in. Avoid the word "rush", don't accelerate sharply, and avoid braking sharply in the first few hundred kilometers.

Speaking here, I wonder if people are clear? In fact, as long as you drive normally and correctly, you will be able to get through the break-in phase smoothly. Moreover, with the improvement of mechanical manufacturing technology, the new engine piston ring and cylinder wall has a good match, the new car break-in is no longer "mandatory" sex, but a "suggestion"! Of course, the car for individuals, is considered a large property, it is best to follow the "recommendations" to treat their cars.

Six, the exploration of automotive safety ABS ASR ESP

When the ABS (anti-lock braking system) has just been introduced, people have to marvel at its excellent safety, ABS device not only means that the car's safety performance is outstanding, and the grade is also quite advanced. Today, the installation of ABS sedan has been quite common, the economy car is also installed with ABS. and with the increasingly high demand for automotive safety performance, some more advanced, more extensive protection range of safety devices have come out, including ASR (drive anti-skid system, also known as traction control system) and ESP (electronically controlled driving smooth system) is the most representative of their birth to make the automotive safety performance has been further improved.

ASR: drive anti-slip system (or traction control system)

Traction control of the car can be reduced by reducing the throttle opening to reduce engine power or by brake control and wheel slip to achieve the purpose of the car equipped with ASR to work in a combination of these two methods, that is, ABS / ASR.

ASR's role is to when the car accelerates The sliding army will be controlled within a certain range, thus preventing the drive wheels from sliding rapidly. Its function is to improve traction; the second is to maintain the driving stability of the car. Driving on slippery roads, without ASR, the drive wheels are prone to slip when accelerating; if it is a rear-driven vehicle, it is easy to throw the tail; if it is a front-driven vehicle, it is easy to lose control of the direction. With ASR, the car will not have or be able to reduce this phenomenon when accelerating. When cornering, if there is a slip of the drive wheels it will cause the entire vehicle to veer to one side, when there is ASR it will cause the vehicle to steer along the correct course.

In ASR-equipped vehicles, the mechanical connection from the gas pedal to the gasoline engine throttle (diesel injection pump operating lever) is replaced by an electronically controlled throttle unit. When the sensor sends the position of the gas pedal and the wheel speed signal to the unit (CPU), the control unit generates a control voltage signal, and the servomotor readjusts the position of the throttle (or the position of the diesel engine lever) according to this signal, which is then fed back to the control unit so that the brakes can be adjusted in time.

ESP: Electronic Stabilty Program (ESP) is an extension of the ABS and ASR systems. Therefore, ESP is the most advanced form of anti-skid device in the current automobile.

The ESP system consists of a control unit and steering sensors (which monitor the steering angle of the steering wheel), wheel sensors (which monitor the speed rotation of each wheel), side slip sensors (which monitor the state of rotation of the car body around the vertical axis), and lateral acceleration sensors (which monitor the centrifugal force of the car when it is turning). The control unit uses the signals from these sensors to judge the operating status of the vehicle and then issues control instructions. ESP and only ABS and ASR cars, the difference between them is that ABS and ASR can only passively react, while ESP is able to detect and analyze the car conditions and correct the driving error, to prevent the problem before it occurs. ESP is particularly sensitive to oversteer or understeer, for example, the car in the road slippery left turn oversteer (turn too quickly) will produce to the right side of the tail, the sensor senses the slide will be quickly braking the right front wheel to make the right side of the vehicle. The sensor senses the slippage and quickly brakes the right front wheel to restore traction, generating an opposite torque to keep the car in its original lane.

Seven, modern automobile engine layout

Engine is the heart of the car's power, its layout is the most important part of the overall layout of the car. In order to meet the different requirements of use, the overall structure of the car and the layout of the form is not the same. Modern automobile engine position in the car can be arranged according to its form is divided into front, center and rear three.

In terms of trucks, the engine front is currently the most widely used form of arrangement. Its advantage lies in the good generality of the engine, both optional inline and horizontal, and can be used V-type engine, maintenance is also convenient. In addition, the floor height of the cargo box is low, and the whole vehicle is also relatively low on the road surface requirements. And the engine of the center, rear with the front compared to the generality of the engine is poor; can only choose the horizontal engine, maintenance is also very inconvenient, the floor of the cargo box is relatively high, the road requirements are also relatively high.

The advantage of engine center is that the axle load distribution is more reasonable, the noise and vibration in the cab is light, and the driver's seat height is low. The most prominent advantage of the engine rear, is because the cab away from the engine, the interior is almost not affected by the engine noise and vibration. At present, the engine rear in the truck is not much, only limited to the rear engine of the car transformed into a truck has been used, the majority of cars using the front form, the car engine using the advantages of the form of the preface is a simple manipulation of the mechanism, the engine cooling conditions are good, defrosting and heating mechanism is simple, the luggage compartment is larger in size.

In order to meet the different requirements of the use of modern cars, the overall structure and layout of the form is not the same, according to the engine and the relative position of the various assemblies are different, the modern car engine layout form and drive the following four kinds of forms are usually:

1. engine front, rear-wheel drive (FR): most of the domestic and foreign trucks, some sedans and some of the buses are using this traditional drive form. It is the front wheel steering, rear wheel drive, engine output power through the clutch - transmission - drive shaft to the drive axle, where the deceleration and torque transfer to the back of the left and right half-axle, drive the rear wheels to make the car run, the front and rear wheels of their respective duties, steering and drive separately, the load distribution is relatively uniform. Drive separately, the load distribution is more uniform.

2. All-wheel drive (NWD): a form unique to off-road vehicles. (such as BJ2020 Cherokee, etc.). Usually the engine front, after the transmission is equipped with a splitter, so that the power is delivered to all the wheels. All-wheel drive power is good, climbing and off-road ability. However, compared with separate front and rear wheel drive structure is complex, high cost, low transmission efficiency.

3. Engine front, front-wheel drive (FF): is the 1990s at home and abroad on the sedan gradually popularized the arrangement form. In order to shorten the length of the car, reduce the quality of the car, often placed in front of the engine before the axle, after the transmission are moved forward, the transmission and drive axle made into one, fixed in the engine next to the power delivered directly to the front wheels, reduce the height of the chassis, to improve the stability of high-speed maneuvering. Such as the common Audi 100 sedan, there are mini-cars (Xiali, Otto, etc.) are used in front of the engine, front-wheel drive driveline layout form, the common engine front, front-axle drive sedan there are two kinds of structure: one is the engine axis parallel to the front axle of the transverse (such as Xiali sedan); the second is the engine longitudinal (such as Santana, Audi and other sedans).

4. Rear engine, rear-wheel drive (RR): it seems to be a replica of the FF car, but only the front of the car, "six organs" moved to the back of the car. This vehicle maintains the advantages of the FF car, but also eliminates the shortcomings of the FF car, due to the car layout tends to be reasonable, and the noise and temperature inside the car has improved, with its unique structure and good performance by the user's welcome.

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