Patent ID: 6162028
Filing Date: 2000-12-19
Classification: F02M,F04B

Abstract:
A fuel pumping device for two-cycle engines, comprising at least a one-piece housing having a compression chamber, a first housing chamber, and a second housing chamber; connector means arranged on said housing and including a pulse air connector which is pneumatically connectable with a crankshaft of the two-cycle engine, a fuel aspiration, and a fuel pressure connector; flap valve means including a first flap connector valve and a second flap valve; a pump piston; a diaphragm on which pulse air acts and which drives said pump piston so that fuel being supplied at said fuel aspiration connector during a pump aspiration stroke is aspirated via said first flap valve into said compression chamber which is located upstream of said pump piston and is pumped during a compression stroke via said second flap valve into said fuel pressure connector, said pulse air connector terminating in said first housing chamber into which said pump piston also projects and which is bordered on one side by said diaphragm; an externally actuated drive unit having a pressurizing tappet; spring means acting on each side of said diaphragm, said spring means including a first spring element arranged in said first housing chamber and supported on said diaphragm via a separate pump piston, and a second spring element supported at least during low engine rpm on said pressurizing tappet of said externally actuated drive unit, which acts in a compression direction during a compression stroke of said pump piston, said spring elements being prestressed and maintaining said diaphragm in a center position if the same air pressure prevails on both sides of said diaphragm and, when said drive unit is attached, it is turned off and is in a position of rest, so that during a suction stroke and a pressure stroke said diaphragm can move past the center position.