On 07/04/16 15:25, michael adams wrote:
"Roger Mills" wrote in message
...
On 07/04/2016 12:38, michael adams wrote:


I'm not concerned about the engine.

That's the problem - Mr Plowman *is*.

For the wheels to be turning or accelerating fastest -
in the absence of the car being powered by external
factors such as the wind propelling the body, they
need to be subject to the maximum available torque.


Indeed. And you obtain that by running the engine at max power and using a suitable
gear ratio. But Mr Plowman doesn't accept that. He says that you have to run the
*engine* at max *torque*. So he would end up using a lower engine speed - producing
less *power* - with higher gearing which provides *less* torque multiplication -
resulting in less torque at the wheels. Mad!

Sorry, but maybe I'm missing something here.

Basically the engine is pistons on con rods going up and down
which is converted to rotary motion by cams on the crankshaft
which is attached to a flywheeel.

And as I understand it anyway, its from the flywheel that engine
torque, is measured.

And so my question is this.

If the engine is running at maximum power, and thus the crankshaft
is turning as fast as possible, then how is it possible for less than
maximum torque to be delivered to the flywheel ?

Torque != angular momentum.

You could have it spinning at 6k RPM but the slightest load (in terms of
a braking torque opposing the motion) slows it down.

You could have the same engine running at 3k RPM and it takes a much
much larger braking torque to slow the engine.