[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]

*To*: sargent@symposiafoundation.org*Subject*: Conrod force/acceleration*From*: quk@isham-research.demon.co.uk (Phil Payne)*Date*: Mon, 26 Jan 1998 22:17:30 GMT*Cc*: quattro@coimbra.ans.net*Reply-To*: phil@isham-research.demon.co.uk*Sender*: owner-quattro@coimbra.ans.net

In message <34CC6849.9380FB3@novagate.com> Sargent Schutt writes: > Phil Payne wrote: > > > In message <34CBEB4D.B0BB2005@novagate.com> Sargent Schutt writes: > > > > > When there is no velocity, there is no > > > acceleration. Acceleration can be zero while velocity is constant, but if > > > velocity = 0, acceleration = 0; acceleration is nothing more than the rate > > > of change in velocity. At TDC velocity is zero, and therefore acceleration > > > is zero, too. Yet the engine is most definitely running. > > > > No - almost completely wrong. > > > > And, if velocity is constant, acceleration _MUST_ be zero. > > > > Think again of the bungee jumper - his BDC (zero velocity) is the moment of > > _maximum_ acceleration. The rope exerts its greatest force when it is fully > > stretched (Hook's Law). > > BDC would be the moment of zero acceleration. In the moment *immediately* > preceeding and following would be his maximum acceleration. There is an instant > in time when velocity, and therefore acceleration are zero. ^^^^^^^^^ There's your problem - there is no such link. In the case of the velocity of the piston - it changes direction. Expressed in any units, the sign changes and there is therefore a point at which the graph crosses the X axis. At this point, velocity _is_ zero. There is no such change (at TDC/BDC, anyway) in acceleration - the sign doesn't change as slowing in one direction gives way to speeding up in the other, and thus the graph doesn't cross the X axis and there's no instantaneous zero. -- Phil Payne Committee Member, UK Audi [ur-]quattro Owners Club

- Prev by Author:
**BTDT's on rear crank seal?** - Next by Author:
**carbon fibre driveshafts** - Prev by thread:
**Conrod force/acceleration** - Next by thread:
**Re: Conrod force/acceleration** - Index(es):