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what does the red line on a speedometer mean
What does the red line on a speedometer mean: It indicates that the speed in the red line area is the limit of the engine, and the engine may be damaged at this speed.The engine speed is related to the number of work done per unit time or the engine effective power, that is, the engine effective power changes with the speed. Theoretically, the higher the engine speed is, the greater the engine power is theoretically.
1、The engine limit is clearly specified in most automobile user manuals. Do not let the engine speed run in the red line area for a long time. The position shown in the red line area is the engine limit. At present, all engines are equipped with electronic control systems. When the engine speed reaches the specified maximum value, that is, the maximum value in the red area, the engine computer stops fuel injection to avoid continuous increase in speed.
2、This operation is commonly known as "fuel cut-off".The reason for "fuel cut-off" is that running the engine under high load for a long time will accelerate the wear of the engine, and there are also certain potential safety hazards. Therefore, it is recommended not to make the engine work under the limit state for a long time. When the engine operates under extreme operating conditions, it usually reaches 6000-7000 revolutions, or even higher speed. This increase in speed will lead to an increase in the number of times the engine does work and more heat is naturally generated, so the engine temperature will be higher at high speed.However, some vehicles with low cooling system efficiency will cause high engine temperature, causing the car to "boil".
3、 Reasonable engine speed If you are driving an automatic transmission vehicle, you are lucky. Don't worry about the engine speed, because automatic transmission vehicles will automatically shift up and down according to the engine speed.However, if you drive a vehicle with manual transmission, it is recommended that you keep the engine speed between 2000 and 3000 revolutions. Generally, in this speed range, the engine will form a balance between power and fuel consumption. It can not only meet the demand for power, but also achieve certain fuel economy.
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