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Why Diesel Engine Has More Torque But Accelerates Slow?

Views: 99     Author: Site Editor     Publish Time: 2021-04-27      Origin: Site

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Why Diesel Engine Has More Torque But Accelerates Slow?

Why Diesel Engine Has More Torque But Accelerates Slow?

The higher torque and slower acceleration of diesel engine is determined by the combustion characteristics of diesel. Because of this combustion characteristic, KPV936 high speed diesel engine and gasoline engine have different working mode.



1. Diesel Engine and Gasoline Engine Have Different Ignition Methods

Compared with gasoline engine, KPV936 high quality diesel engine also has to go through four strokes of aspiration, compression, work and exhaust. But due to the different combustion characteristics of the two fuels, they adopt different ignition methods.


Ordinary gasoline engine inhales the mixture of oil and gas during air intake, and these mixture gases are compressed and ignited by spark plug. The diesel engine inhales pure air in the intake stroke. When the piston is close to top dead center during the compression stroke, the fuel injection pump pressurize the diesel oil and injects the diesel into the cylinder through the fuel injector, and it mixes with the compressed high-temperature and high-pressure air to form a combustible mixture.


Because the compression ratio of diesel engine is very high, the pressure and temperature in the cylinder are still very high after the compression is terminated, which greatly exceeds the spontaneous combustion temperature of diesel. Therefore, it will be mixed with air in a short time and spontaneous combustion will occur immediately. At this time, the pressure and temperature in the cylinder increase at the same time. Driven by high pressure, the piston moves downward and drives the crankshaft to rotate to do work. The exhaust gas is discharged into the atmosphere through the exhaust pipe. Therefore, the diesel engine has no ignition system. It is a compression ignition type, and the gasoline engine is really ignited by the ignition system.



2. Different Combustion Characteristics Determine Different Ignition Modes

The ignition mode of KPV936 new motor diesel engine is determined by its combustion characteristics. Diesel is different from gasoline. It is not easy to ignite. It is difficult to ignite a bowl of diesel directly with a flame. This characteristic of diesel leads to its slow combustion speed, and the compression ignition mode of diesel engine is doomed that the engine speed design is very difficult to be very high. Because no matter from the combustion speed orignitionmethod, theignitionand combustion speed of diesel engine can not reach the level of gasoline engine. Therefore, the speed of diesel engine is generally not high.


The power of the engine is the torque multiplied by the speed. Under the premise of a certain torque, the smaller the speed is, the smaller the power value will be.


(1) Change the Speed

In the field of gasoline engine, engineers usually increase the engine speed to get more power, because compared with torque, it is easier to improve the speed. However, due to the combustion characteristics of powerful high speed diesel engine, its combustion speed can not meet the rotation rate, which limits the improvement of its power, so the maximum power value of general diesel engine is not very large.


(2) Changing Torque

Because of the combustion characteristics of diesel, it is impossible for the engine to rotate at a high speed like that of a gasoline engine. Therefore, efforts should be made to improve the engine torque. In general, diesel engine designers increase torque by increasing piston stroke and using longer connecting rods. The low speed of diesel engine is determined by combustion characteristics. Therefore, even if the connecting rod is shortened, the speed can not be increased. Therefore, it is better to obtain greater torque with a longer connecting rod.


In short, the different combustion characteristics of diesel and gasoline determine that KPV936 water cooled diesel engine and gasoline engine have different ignition mode and working mode.

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