> > From: "Fritz" <[email protected]> > Date: 2004/11/16 Tue PM 12:11:07 EST > To: "KRnet" <[email protected]> > Subject: Re: KR> Re: Facets / Vaccum/ Pulse pumps > > As far as I know you only have a crankcase pulse on a 2cycle engine, > not a four! > KR-2 in N.E PA. Not quite true. On 2 stroke and 4 stroke engines you have a crankcase pulse in the case of a 1-Cylinder engine as well as a two cylinders when they are opposed and have a 180 degree phase difference, meaning that both pistons move away and towards the crankshaft at the same time. The pulse is simply created by the displacement of air from the backside of the piston. With more than two cylinders the engines are typically balanced so that the pulse becomes weaker.
Wolfgang
