Direct injection fuel system utilizing water hammer effect

A method for operating a fuel system during start up utilizing gasoline direct injection for an internal combustion engine including a first pump, a check valve fluidly coupled downstream of the first pump, a second pump fluidly coupled downstream of the check valve, a bypass circuit including a bypass valve and a pressure regulator fluidly coupled between the check valve and the second pump, and a fuel rail fluidly coupled downstream of the second pump, comprising;

• closing the bypass valve;
• driving the first pump in a higher pressure mode while the bypass valve is closed until the fuel rail pressure has reached the pressure delivered by the first pump;
• opening the bypass valve;
• and
• closing the bypass valve abruptly after a specified duration from the opening of the bypass valve to generate a high pressure wave that propagates downstream of the second pump to increase the fuel pressure in the fuel rail prior to ignition of the engine.

A system for delivering fuel to an internal combustion engine utilizing gasoline direct injection comprising;

• a first pump;
• a second pump;
• a bypass circuit containing a valve;
• a check valve fluidly connected downstream of the first pump and upstream of the second pump;
• a fuel rail fluidly coupled downstream of the second pump;
• a plurality of direct fuel injectors coupled to the fuel rail;
• and
• a controller that operates the first pump while the second pump is disabled to recirculate fuel into the fuel tank for a specified amount of time via the bypass circuit, abruptly closes the valve to generate a high pressure wave increasing the pressure in the fuel rail, and actuates the injectors to deliver fuel for a first combustion event during an engine start.

A method for operating a fuel system during start up utilizing gasoline direct injection for an internal combustion engine including a first pump and second pump, an electromechanical valve, and a check valve fluidly coupled downstream of the first pump, the fuel system further including a fuel rail downstream of the check valve and direct fuel injectors coupled to the engine, comprising:

• generating a flow of fuel in the fuel system via the first pump during an engine start before ignition of the engine;
• actuating the valve during the fuel flow to generate a pressure wave that travels through the fuel system past the check valve;
• and
• injecting fuel via the direct fuel injectors at an increased pressure generated by the pressure wave and held in the fuel rail via the check valve, the valve being a solenoid valve, said actuating including repeatedly actuating the valve to generate a plurality of pressure waves that travel through the system and past the check valve to repeatedly increase fuel pressure before engine combustion during the engine start.