maximum power
The physical definition of power refers to the work done by the machine in unit time. The amount of work is certain. The shorter the time, the greater the power value. The higher the power, the higher the speed, the higher the maximum speed of the car. The maximum power is often used to describe the dynamic performance of the car. Generally expressed in horsepower (PS) or kilowatt (kw), 1 horsepower is equal to 0.735 kilowatt. The article originates from the fallen fish- https://www.duoluodeyu.com/2393.html
The calculation formula of power is: power=force * distance/time. The common unit of force is kilogram (kg), the unit of distance is meter (m), and the unit of time is second (s). So the unit of power is kg. m/s. But for the power of cars, traditionally people prefer to express it in terms of horsepower, with the letter PS. Now, the manufacturer usually gives the value of kilowatt (KW) in the product description. The article originates from the fallen fish- https://www.duoluodeyu.com/2393.html
The conversion relationship between them is as follows: The article originates from the fallen fish- https://www.duoluodeyu.com/2393.html
1PS=75kg.m/s=0.7355KW,1KW=102kg.m/s=1.36PS。 Maximum power is one of the most important parameters of automobile engine. Its size mainly depends on the size of the engine cylinder displacement, the amount of fuel burned and the engine speed. The power value is always combined with the engine speed, indicating the power generated at that speed. The article originates from the fallen fish- https://www.duoluodeyu.com/2393.html
Due to the internal friction loss of the engine and the need to drive other machines, the actual effective power figure is always less than the specified value. The ratio of effective power to rated power is called engine efficiency. The article originates from the fallen fish- https://www.duoluodeyu.com/2393.html
The engine power can only be measured by professional power test bench. The working principle of the test bench is similar: connect the engine flywheel with an electronic vortex or water vortex damping device through the intermediate shaft. The engine drives the damping device, and its resistance can be adjusted steplessly. The "resistance torque" or "braking torque" is only on the indicating instrument marked with the corresponding scale through an arm pulling device, so that the power values at different engine speeds can be measured. The article originates from the fallen fish- https://www.duoluodeyu.com/2393.html
Although the test conducted on the vehicle rolling test bench can also give the engine power value, this result is affected by the rolling resistance of the gearbox, axle and tire, so it can only be used as a reference value. The article originates from the fallen fish- https://www.duoluodeyu.com/2393.html
Different countries in the world follow different industrial standards and test methods. The article originates from the fallen fish- https://www.duoluodeyu.com/2393.html
The test principle of German Industrial Standard (DIN) is that the engine is in normal operation, that is, with all auxiliary equipment, including air inlet filter and exhaust device. Some countries, such as the United States, conduct power tests according to SAE standards, excluding auxiliary equipment such as air filters and exhaust devices, that is, it is driven by external power. Therefore, SAE power value is 15%~20% higher than DIN. In Italy, there is also a CUNA standard measurement method. Its condition is that it includes some auxiliary equipment, but does not include the intake filter and exhaust device, so its power value will be 5%~10% higher than the DIN value. The article originates from the fallen fish- https://www.duoluodeyu.com/2393.html
Generally, the power cannot be increased by re calibrating the engine, because almost all modern mass production engines have been calibrated for the upper power limit when they leave the factory. However, there are some ways to increase the number of unit power if it can bear a large cost. The article originates from the fallen fish- https://www.duoluodeyu.com/2393.html
First, increase the intake air volume by smoothing and expanding the intake and exhaust channels, increasing the cross section of the engine valve, improving the compression ratio, changing the opening and closing time of the valve, etc; Secondly, the inlet and exhaust system can be technically debugged, or even the compressor system can be replaced. The article originates from the fallen fish- https://www.duoluodeyu.com/2393.html
All these measures aimed at improving the power will lead to the overall improvement of the engine speed level. Therefore, advanced materials must be used to lighten the moving parts and improve the machining accuracy so that they can withstand a larger load. More robust valve springs, even non-contact ignition systems, should also be used. After this series of transformation, the power of mass production engines may be more than doubled. The article originates from the fallen fish- https://www.duoluodeyu.com/2393.html
Maximum torque
Torque is the force that causes an object to rotate. The torque of the engine refers to the torque output by the engine from the crankshaft end. Under the condition of fixed power, it is inversely proportional to the engine speed. The faster the speed is, the smaller the torque is. On the contrary, the greater the torque is. It reflects the load capacity of the vehicle within a certain range. Torque is an important parameter of engine performance, which refers to the average torque output from the crankshaft end when the engine is running, commonly known as the "torque" of the engine. The greater the torque, the greater the "force" of the engine output, the faster the change of crankshaft speed, and the better the climbing ability, starting speed and acceleration of the car. The torque varies with the engine speed. If the speed is too high or too low, the torque is not the maximum. Only at a certain speed or within a certain speed range can there be the maximum torque. This range is the speed or speed range given when marking the maximum torque. The maximum torque generally occurs in the middle and low speed range of the engine. As the speed increases, the torque will decrease. The unit of torque is Newton meter (N · m) or kilogram meter (Kg · m). The article originates from the fallen fish- https://www.duoluodeyu.com/2393.html
The maximum torque of the engine is related to the design of the intake system, fuel supply system and ignition system of the engine. At a certain speed, the maximum torque can be achieved when the performance of these systems is matched to the best. In addition, the power, torque and speed of the engine are related. The specific relationship is: power=K × torque × speed, where K is the conversion coefficient. When selecting the engine, we should also consider how to use it rationally and not waste the existing functions. For example, it is necessary to turn on the air conditioner in winter and summer in Beijing, and the engine power should not be too small; There is no need to pick up a high-powered engine just for commuting on the urban ring road. Try to select the engine economically and reasonably. The article originates from the fallen fish- https://www.duoluodeyu.com/2393.html
The following are the maximum torque values and descriptions of some models: Alto's maximum torque is only 60.5, which is in the range of 3000-4000 engine revolutions. Among domestic minicars, its maximum torque is also quite small, and the higher one can reach 110-120. However, because its displacement is only 0.8 and the price is cheap, it is understandable; The range of medium and high displacement vehicles is particularly large, ranging from more than 110-700. Generally, the range of domestic mid-range vehicles is 200-350. The Rolls Royce Phantom 7 Series can be the most popular car, and its maximum torque reaches 720 at the engine 3500; Sports cars are generally high. 400 and 500 are very common. The maximum torque of the modern Coolpad FX2.0 can only reach 102/6000, which is really unreasonable; Among off-road vehicles, the domestic ones are generally in the range of 180-300 (of course, the domestic ones are also relatively small), while the imported ones are higher. In Europe and the United States, the average is 400-4800. However, Freelander 2004 has only 240/3000, and its guards are only 300/1950. The article originates from the fallen fish- https://www.duoluodeyu.com/2393.html
