High-speed forget to hang five gears, have been using four gears, there is no problem, but the engine speed is slightly higher, there is no other harm; for this kind of problem you should not have any worries, very fortunate that your car transmission has five gears, if your car is a four-speed box, then according to your mentality, are you ready to resist the car to run high speed? In the past, when the four-speed transmission was used, couldn't the highway be run? Can run, nothing more than the engine speed is high, but the engine is not afraid of high speed!
Now the car gearbox gears are more, the transmission ratio range is made very large, coupled with the turbocharged engine, so today's car engine speed is generally low, so the formation of a low speed concept; so now many friends, think that the engine should be low speed, just like two thousand revolutions is normal, the speed is slightly higher, this pain ah, afraid of wear, afraid of wear and damage, think that four or five thousand revolutions is taboo? In fact, the self-priming car of more than twenty years ago, which speed is not easy to exceed four thousand? Five thousand spins are also common!
Four-speed, no high-speed transmission
Many years ago, I drove a four-speed car, the four-speed transmission ratio is one (direct transmission, no high-speed gear), do you know how high the speed of the contemptible car reaches 110Km? The speed reaches nearly 5,000 rpm, and this speed, taken to today," will it be difficult for many extreme car lovers to understand? But even if you run a high speed, a speed of about 5,000 times, did not break the engine is not, why are the current riders so afraid of the high engine speed? To know that today's processing technology to create a machine, far stronger than the past, the past machine is not afraid of high speed, how can the current machine can not run at high speed?
As shown in the figure above, this is a six-speed machine, one gear more than your car's transmission; in the past four-speed transmission, the gear ratio of four gears was about 1.00 (in order to prevent the setback caused by too large a drop, the gear position is less, the gear ratio cannot be lowered); so it is normal to run 120Km and the speed of five thousand revolutions; later, low speed is good for emissions and fuel economy, and a high-speed gear (fifth gear) is added, the gear ratio is reduced to about 0.80, and then when running 120Km, The engine speed can be reduced to about four thousand revolutions, which is actually an improvement; as the requirements for fuel economy and emissions continue to increase, some car companies are equipped with a sixth gear (manual, automatic to achieve ten speeds)!
Take the data on the figure as an example, the six-gear gear ratio is 0.69, then in the fifth gear, 120Km if four thousand revolutions, then with the sixth gear, running to 120Km when the speed is only more than three thousand revolutions, so that the speed is reduced again; this is the transmission development process, in fact, increase gear, reduce speed (speed), not because of fear of the engine can not stand, but in order to obtain better fuel economy and emissions, now those five-speed cars on the market, The highest gear gear ratio is generally around 0.65, so running 120Km speed is generally out of three thousand turns, and running 120Km with four gears is nothing more than the engine breaking through four thousand turns, close to five thousand turns, what is the problem, sticking to the red line rotation is fine, not to mention four or five thousand turns!