That`s what I thought too Andy. If abba comes back and confirms it i`ll alter the title.

oilrag

Hi

Yes that what i meant, to put the gear on neutral

title edited for you, abba

Edited by oilrag on 07/07/2010 at 11:42

All modern engines cut off the fuel on a trailing throttle, above a certain revs. Lets face it, why do you need fuel going to the engine when you lift off?

A good engine software would not allow the driver to notice this, mine puts the fuelling back on at 1200 RPM

Although coasting is not deemed to be illegal as such, coasting can be regarded as not being in control of the vehicle. I recall a bus driver being prosecuted for this. There was a police inspector on the bus in civies. Regards Peter

I wouldn't have thought it is quite so clear cut.

1) If you have an engine without any electronic control system to throttle back when the throttle demand < equivalent crankshaft speed, then you will lose MORE energy by NOT coasting. This is because the throttle is still running at idle therefore, fuel is still flowing and the engine and the transmission act as a brake.

2) It is true in modern engines that the control system feedback will effectively reduce fuel flow for the condition where throttle demand < equivalent crankshaft speed and the 'surplus' energy can be transferred to ancillary components. However, the energy transferred to the engine is transferred through the transmission and this is a source of energy loss. The frequency response of the engine is non-linear. I would suggest it is not as simple as the fuel flow is switched off, therefore efficiency is increased because you can run ancillaries.

The only way to truly find out which is more efficient in the 2nd case is to find some real recorded data from testing. Don't suppose anyone has got any?

Edited by angryman on 09/07/2010 at 18:36

Same here, but only in a straight line!