Patent ID: 6481419
Filing Date: 2002-11-19
Classification: F02M

Abstract:
A unit injector system for internal combustion engines, in particular diesel engines, comprising a pump element for subjecting fuel in a pump chamber to high pressure, an injection element for injecting the pressurized fuel into the combustion chamber of the engine, a control valve which opens and closes a connection between said pump chamber and a low-pressure chamber, and a throttle device (13) disposed in the connection between said pump chamber and said low-pressure chamber, said throttle device controlling flow therethrough as a function of the position of said control valve,wherein said control valve includes a first valve body (6) with a first valve seat face (7) and a second valve body (11) with a second valve seat face (17), which are received, capable of reciprocation, in a housing (1), and wherein in a first valve position, said first valve body (6) is spaced apart from said second valve body (11), and both said first valve body (6) having said first valve seat face (7) and said second valve body (11) having said second valve seat face (17) rest on their associated valve seat edges (8; 18), as a result of which the connection between the pump chamber and a low-pressure chamber is closed; wherein in a second valve position, said first valve body (6) comes to rest on said second valve body (11), and said first valve body (6) having said first valve seat face (7) lifts from its associated valve seat edge (18) whereby fuel can flow to said throttle (13) in the second valve body (11), said throttle communicating with the low-pressure chamber; and wherein in a third valve position, said second valve body (11) comes to rest on a stroke end stop (15), and both said first valve body (6) having said first valve seat face (7) and said second valve body (11) having said second valve seat face (17) are lifted from their associated valve seat edges (8; 18), whereby a connection without a throttle (13) is opened up to the low-pressure chamber.