Power is not required to determine acceleration or vehicle speed (details are explained here).
The higher the power, the faster the car, so you may think that power is necessary to calculate speed. Here we explain the difference between torque and power.
■Relationship between torque and output
as below. Power is the product of torque and rotational speed.
Power is the work done per unit time, so as you can see from the above formula, the higher the power, the longer the distance the car will move per unit time (= higher vehicle speed), or the harder it will be to carry a heavy object even if the vehicle speed is constant.
Therefore, higher power does not necessarily mean higher vehicle speed, which is why power is not required to calculate acceleration.
＜Torque-power characteristics＞
as below. The torque characteristics shown here are typical engine characteristics.
Power is determined by the engine's torque and rotational speed, so even if the gear of the car changes, if the rotational speed remains the same, the power will not change.
The fact that the vehicle speed changes depending on the gear position even though the power is the same means that the gears have the role of a distributor that determines how the power is distributed between torque and speed.
■Driving performance curve
A driving performance curve shows the driving force characteristics when the gear stage changes with respect to the characteristics of the engine, and this curve represents the driving performance of the actual vehicle.
In AT's D range, you don't need to worry about it because it will automatically make the optimal shift change, but in AT manual mode or MT vehicle, you can use this to know the optimal shift point.
For efficient driving, select the gear that provides the most driving force at each vehicle speed.
1st gear has the highest driving force, so you might think it's fine to just drive in 1st gear all the time, but the engine speed will rise all at once and reach overrev, making it impossible to increase the vehicle speed any further.
I will explain the characteristics of running resistance with respect to slope angle. For example, if you compare the running resistance at a gradient angle of 10% and the driving force in 6th gear, the running resistance is always higher, so you cannot go up a gradient of more than 10% in 6th gear.
＜Motor torque characteristics＞
Electric cars do not have a transmission, and can cover all vehicle speeds with just the motor (see here for the relationship between rotation speed and vehicle speed).
The torque characteristics of the motor are as shown below, and smooth driving can be achieved without sudden changes in driving force due to gear shifting.
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