jack action said:
We are talking about an acceleration at a given velocity (other than zero).
I am certainly not excluding zero velocity. You would certainly like to exclude it since it makes your claim obviously wrong, but I do not consent to the limitation.
jack action said:
Is power or torque a better indicator of acceleration?
Let’s examine it for the simple lossless case:
Wheel torque is always proportional to acceleration with a simple constant of proportionality.
Power is related to acceleration by a proportionality which is not constant.
At v=0 power becomes infinite, but acceleration and wheel torque maintain their standard proportionality.
At small but nonzero speeds power becomes arbitrararily large but acceleration and wheel torque do not.
Wheel torque and power are not independent but are closely related to each other by speed.
The combination of power and speed that is related to acceleration is itself proportional to wheel torque with the above simple constant of proportionality.
Wheel torque is proportional to acceleration from rest, power is not.
With a CVT power is constant, but both wheel torque and acceleration are not and at all times the wheel torque is proportional to the acceleration.
With a typical powertrain in a fixed gear the peak wheel torque often occurs at lower speeds than the peak power, the peak acceleration occurs at the speed of the peak wheel torque not the peak power.
For constant wheel torque acceleration is constant, while power is not.
So clearly, wheel torque is more directly related to acceleration than power. So what is the value of power: first it is the primary criterion to use when selecting an engine. Second, power is conserved but torque is not, so the relationship between wheel torque and engine torque is not as simple as the relationship between wheel power and engine power. Third, power is more relevant for determining peak speed. I am sure there are many other examples where power is more directly relevant than wheel torque, but acceleration is obviously one of the exceptions where wheel torque is more directly relevant.
jack action said:
Given those numbers, it must be very clear to anyone that the orange engine can produce way more acceleration than the blue one.
Sure, and it does so precisely by converting that engine power into greater wheel torque. As I said above, power is the primary criterion for selecting an engine. The wheel torque is not independent of the engine power, but the wheel torque remains the quantity that is more directly related to acceleration.