On 02/04/2016 14:15, Dave Plowman (News) wrote:
In ,
Roger wrote:
On 02/04/2016 11:26, Dave Plowman (News) wrote:
In ,
Roger wrote:
In fact, I invited Mr Plowman to consider these two scenarios - with
a stepless transmission holding the engine either at its max torque
point or at its max power point - but he ruled it invalid because
such transmissions don't exist.

Sigh. Only because the transmission type makes not a scrap of
difference to my original statement. If you did want to discuss
different types of transmissions I'd be happy to join in.


Maybe you'd better remind us what your original statement was, since it
got lost in the mists of time!

Can't be bothered. Many seem unable to read or understand a simple
statement.

Seems to me that we are arguing over semantics and may even be in
agreement over the engineering principles (though I'm not 100%
convinced!). So let's try again.

I'm not arguing over semantics.

Q1: How do you maximise the acceleration of a car in a given gear?

A1: By using full throttle and running the engine at its maximum torque
speed.

If you ran the car at maximum torque there'd be no acceleration, since
that occurs at specific revs.

Of course there would. It would only be at its max value at the max
torque point itself - which may actually cover a range of speeds since
some engine torque curves are flatish rather than peaky at max torque.
We're talking about a dynamic rather than static situation anyway.
Acceleration is the RATE OF CHANGE of speed and is a continuously
variable function. If you're defining acceleration as a step change in
speed it's little wonder that you're living on a different cloud from
everyone else.

Maybe I need to change A1 for your benefit, thus:

A1: By using full throttle and allowing the car to accelerate over a
speed range which encompasses the max torque speed of the engine.
Maximum acceleration will occur as the engine passes through its max
torque point.

[In actual fact, it may not! As the car speed increases, the aerodynamic
drag increases as the square of the speed. The effect of this - which we
have so far ignored in this discussion - is that maximum acceleration
MAY occur slightly below the max torque speed because the increase in
drag may more than offset the increase in torque.]


Q2: How do you maximise the acceleration of a car at a given speed?

A2: By using full throttle and by choosing a gear which enables the
engine to develop its maximum power (or as near to it as the choice of
gearing permits).

And that's where you're wrong.

Unless I misunderstand you, you are saying that the answer to Q2 is A1.
If so, you are simply WRONG!

As I said before, some seem totally incapable of understanding a very
simple and basic condition.


I think we agree on THAT! What we DON'T agree on is who those people ARE!!!!
--
Cheers,
Roger
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