Internal combustion engine common-rail injection system with a fuel premetering device
AssigneeC.R.F. Societa Consortile per Azioni
InventorMario Ricco
Life of this patent
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Abstract
The fuel premetering device has a valve controlled by an electromagnet and located between a delivery conduit of a high-pressure pump supplying fuel to a common rail, and a drain conduit for draining surplus fuel. The valve is normally closed by a spring, and the electromagnet is energized to open the valve in opposition to the spring. The electromagnet is energized by a current varying in response to the operating conditions of the engine, and which is varied by a control unit from zero, at which the valve is closed completely by the spring, to a predetermined value, at which the electromagnet opens the valve completely, so that premetering is self-adaptive.
Claims9
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.
Dependencies are inferred from the claim text.