Patent ID: 6672290
Filing Date: 2004-01-06
Classification: F02M

Abstract:
A common-rail injection system for an internal combustion engine comprising:a common rail (6); a high-pressure pump (7) connected to said common rail (6) by a delivery conduit (8) to deliver fuel to said common rail (6); and a premetering device (17) connected to said delivery conduit (8) and to a drain conduit (16) which is connected to a fuel tank (14); said premetering device comprising: a valve (18) connected to said delivery conduit (8) and to said drain conduit (16) to control pressure of the fuel delivered to said common rail (6); an elastic means (37) acting to close said valve (18); and an electromagnet (19) acting in opposition to said elastic means (37) to open said valve (18) and to control pressure of the fuel delivered to said common rail (6); wherein said elastic means (37) is calibrated to close said valve (18) with a predetermined force such that when fuel pressure in said delivery conduit (8) exceeds said predetermined force of said elastic means (37), said valve (18) is opened and fuel can flow to said drain conduit (16); said valve normally being closed by said elastic means and said electromagnet de-energized.