RE: [Algorithms] Car engine behaviour
Brought to you by:
vexxed72
From: Robert D. <bli...@go...> - 2006-04-27 13:18:29
|
> Now, if it > is just as easy to accellerare from 4 to 5 kph as 40 to 41, then why > can high gears do the latter and not the former? Even if it's not from > a stand-still, accellerating in 5th gear from 20mph is not very > effective, to the point that I don't think I've ever even attempted it, > I expect that commonly the RPM would drop to the point of stalling. Take a look at a torque curve and you will see why. Put a car in 1st gear at 10 mph, and it may well require 2000rpm, which is certainly well into the part of the torque curve where you actually get some power, and probably quite a decent amount of it on most cars. Now put it in 5th gear and it would require 400rpm (it would on my car anyway) which is actually below the stall point for most petrol engines. There is no torque whatsoever at this level - in fact on my car there is no torque below about 1000rpm. You know that thing where Tom said about 10% variation in torque ? He was talking about the middle bit of the curve, the bit which you try to keep your engine in all the time. The bits outside that collapse to zero pretty quickly. Rob |