Patent ID: 6076507
Filing Date: 2000-06-20
Classification: F02B,F02D,F02M

Abstract:
A transfer pump system for preventing fuel leakage into the combustion chambers of a multi-cylinder internal combustion engine equipped with a fuel injection system including a plurality of open nozzle injectors and a common rail for supplying fuel to the injectors from a fuel supply having a fuel tank such that upon engine shut down at least one injector may be stopped in an open nozzle condition to form a leakage path for fuel to flow from the injector's open nozzle into a corresponding engine cylinder and further having with an engine fuel supply system, fuel drain passage for returning fuel from the engine to the fuel tank, and a source of electric energy and a fuel supply system including a engine fuel shut off valve, an electronic control valve assembly for supplying fuel under varying pressure to the common rail to control engine operation, and an electronic engine controller for providing control signals to the electronic control valve assembly to vary the pressure of the fuel in the common rail to control engine operation and to the engine fuel shut off valve to change the voltage supplied to the engine shut off valve to shut off fuel flow into the common rail upon engine shut down, comprising:anti-knock means for preventing leakage of fuel into the cylinders of the engine subsequent to shut down by removing fuel from the common rail, includingtransfer pump means in fluid communication with the common rail and the fuel tank for pumping fuel out of the common rail and into the fuel tank, wherein said transfer pump includes an electric drive motor,a drain line for connection between said transfer pump means and the fuel drain passage to allow fuel pumped out of the common rail by said transfer pump means to be returned to the fuel tank, said drain line includes a check valve for allowing fuel flow out of the common rail and for preventing reverse fuel flow into the common rail from the fuel tank, andtransfer pump control means for actuating said transfer pump means for a period of time following engine shut down to allow said transfer pump means to remove a sufficient amount of fuel from the common rail to prevent fuel from leaking through an open nozzle of an injector into a corresponding engine cylinder upon engine shut down, said transfer pump control means includes a voltage sensor for determining engine shut down when the voltage supplied to the engine shut off valve is changed and a relay for connecting said electric drive motor to the source of electric power when said voltage sensor determines that the engine has been shut down and a timer for opening said relay to remove said electric drive motor from the source of electrical power after a predetermined time interval following initial shut down of the engine.