On 04/04/2016 14:47, Dave Plowman (News) wrote:


You seem to be wanting to pick the torque produced by the engine at peak
BHP in one gear and compare it to the torque produced in another gear.

But that is precisely what one does when changing up through the gears.
Go up to max power and beyond and then change to the next gear - which
will give you more input torque but less output torque.



Are you trying to say acceleration is uniform at all points in every gear?

Of course not. It largely follows the torque curve (minus the drag!) in
each gear, and then there's a step change (downwards!) when you change
to the next gear.


Care to explain why a CVT holds the engine at maximum torque, then?

I'm not aware that it does. If I were to design one, it certainly wouldn't!

But then you're obviously not into car design. ;-)

When did you last design a car? The work we did a Rover a few decades
ago on the Perbury transmission (a derivative of the earlier Austin
Hayes transmission) certainly aimed to run the engine at max power for
max acceleration. I've no idea what Daf did with the belt drive system.



Newton's first law! A body remains at rest or moves at a constant speed
in a straight line unless acted upon by "forces".

And the 'force' in this case is torque.


Force and torque don't even have the same dimensions!! Read what I said
below.


In order to accelerate a car, you need an external force. That force is
imparted to the car through the contact patch. The torque imparted on
the wheels through the transmission manifests itself as a force at the
contact patch which tries to push the road backwards. But the road
usually wins, and pushes the car forwards instead. *That* is the thrust
to which I was referring.



--
Cheers,
Roger
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