Pleas don't talk for me Turnip. You have enough trouble talking for yourself. Especially when you've *totally* missed my point.
Only you could be so stupid as to think I don't know that a gearbox multiplies torque. You, on the other hand, appear not to understand how power relates to torque.
From 0-10 mph? Doubt you could measure it. From 150-160 mph it could be very significant. Depending on the design of the vehicle. Which you haven't specified.
No such things as thrust at the wheels. It's a term used for jet engines.
You're making this up as you go along...
None of which has any bearing on the point.
BUT I *DON'T* FOR GOD'S SAKE!!!! Why on earth do you think I do?
Mr Plowman refuses to accept that. I don't and never have. I've always said you need to run the engine at peak power.
Again I challenge you to quote anything I've said which suggests otherwise.
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.
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.
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.
Force and torque don't even have the same dimensions!! Read what I said below.
In that case, please explain how a car gets accelerated by a horizontal force. It certainly isn't pushed along by its exhaust gases!
Sorry - if you don't understand that, there's really no point in discussing this any further.
Roger has it right. I misunderstood him.
Andy
I thought the idea was to run so far past peak power that when you changed up you were at the same power output the other side of the peak? So no steps?
Andy
I already said that!
Andy
That would be the ideal, and may be achievable if you have a lot of closely spaced gears. Otherwise you're likely to reach valve bounce or, in the case of a diesel, hit the governor before reaching the point where the next gear up will allow the engine to produce the same amount of power.
In all the calculations I did when I was doing this for a living - albeit a few decades ago - the next gear up always dropped you further down the power curve. When doing a practical road test, you could counter that to some extent by not letting the engine revs drop during the gear-change so that you got an inertial 'kick' when you let the clutch in.
That reminds me of one factor which we had to include in performance calculations which hasn't been discussed here - namely the effect of the engine's own moment of inertia. In a low gear, quite of lot of engine torque is used up accelerating the engine itself - reducing the amount available for accelerating the vehicle. The "effective mass" of the engine, which was different for each gear, had to be added to the vehicle mass when calculating acceleration.
That is PROBABLY optimum for uniform power loss with RPM each side of the peak. # But a lot of performance engines develop peak power at peak RPM and are limited so as not to go beyond that point.
Balanced lightened flywheel/crank lightened pinions..BTDTGTTS
Is that the best you can find in order to assert that I agree with Mr Plowman?
The *only* thing we agree on is that "some people" are incapable of understanding simple basic principles. I guess that even you would agree on that.
What we *don't* agree on is who those people are. Mr Plowman almost certainly - erroneously - puts me in that category, and I definitely put
*him* in it.I'm afraid you'll have to do better than that! Your apology is still awaited.
well if you that is the case, sorry. OK?
Which as precisely nothing to do with the original point. Which was at which point on an engine's rev range you get the best acceleration.
Just to see if I was missing something that others found so obvious, I asked this question on a forum designated to engine building and tuning, etc.
'At what point on an engines output do you get maximum acceleration?'
And the answers were near unanimous. Peak torque.
I'll take the views of those guys over the bar room mechanics here any day.
A very successful concept, obviously.
Read the first paragraph of this. ;-)
I've told you.
Accepted - thanks!
The idea was good but oil technology was not sufficiently developed in the 1930's to make it work reliably without wearing out the rubbing parts.
I presume you're referring to the bit where it says "method of transmitting power at a variable speed, but at the maximum torque".
You'll note that it's not specific as to whether it's talking about input or output torque.
Later in the article it talks about using a high ratio in order to run the engine at low speed and high torque for maximum fuel efficiency. This makes perfect sense, but is irrelevant as far as any discussion about acceleration is concerned because nowhere does it mention acceleration - only steady state.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.