High pressure fuel injection system for internal combustion engine

A high pressure fuel injection system for an internal combustion engine comprising:

• a low pressure fuel source;
• a high pressure fuel supply pump, connected to the fuel source, for pressurizing fuel from the fuel source;
• a common rail, connected to the high pressure fuel supply pump, for accumulating therein pressurized fuel sent from the high pressure fuel supply pump;
• injectors, connected to the common rail, for injecting fuel into the internal combustion engine;
• a high pressure regulator including a mechanical pressure regulator and an electromagnetic pressure regulator, connected to the common rail, for relieving fuel pressure in the common rail and returning fuel to the low pressure fuel source;
• and
• an electronic control unit for controlling operation of the high pressure fuel supply pump, the injectors and the electromagnetic pressure regulator according to engine operating conditions;
• wherein,
• fuel volume from said high pressure fuel supply pump is controlled by the electronic control unit to produce a predetermined fuel pressure in said common rail;
• and
• fuel pressure in the common rail is decreased by controlling the electromagnetic regulator and the high pressure fuel supply pump upon such request from the electronic control unit, wherein the fuel pressure in the common rail is gradually decreased by opening and closing a valve of the electromagnetic pressure regulator in a duty control fashion upon such request from the electronic control unit.

A high pressure fuel injection system for an internal combustion engine comprising:

• a low pressure fuel source;
• a low pressure fuel supply pump, connected to the low pressure fuel source, for pumping up fuel from the low pressure fuel supply source;
• a high pressure fuel supply pump, connected to the low pressure fuel supply pump, for pressurizing fuel sent from the low pressure fuel supply pump;
• a common rail, connected to the high pressure fuel supply pump, for accumulating therein pressurized fuel sent from the high pressure fuel supply pump;
• injectors, connected to the common rail, for injecting fuel into the internal combustion engine;
• an electromagnetic pressure regulator, connected to the common rail, for relieving fuel pressure in the common rail and returning fuel to the low pressure fuel source;
• a pressure sensor for sensing fuel pressure in the common rail;
• and
• an electronic control unit for controlling operation of the high pressure fuel supply pump, the injectors and the electromagnetic pressure regulator according to engine operating conditions;
• wherein:
• upon sensing a preparatory signal indicating that the engine will be started soon under a high ambient temperature, and before the engine is actually started, the low pressure fuel supply pump is operated to send fuel to the common rail through the high pressure fuel supply pump;
• at the same time, the electromagnetic pressure regulator is operated to open its passage for purging vapor in the system including the common rail to the low pressure fuel source;
• and
• the passage is closed when the pressure sensor senses that the fuel pressure in the common rail has reached a predetermined level.

A high pressure fuel injection system for an internal combustion engine comprising:

• a low pressure fuel source;
• a low pressure fuel supply pump, connected to the low pressure fuel source, for pumping up fuel from the low pressure fuel supply source;
• a high pressure fuel supply pump, connected to the low pressure fuel supply pump, for pressurizing fuel sent from the low pressure fuel supply pump;
• a common rail, connected to the high pressure fuel supply pump, for accumulating therein pressurized fuel sent from the high pressure fuel supply pump;
• injectors, connected to the common rail and mounted directly in respective cylinders of said engine, for injecting fuel into the internal combustion engine;
• a high pressure regulator, connected to the common rail, for relieving fuel pressure in the common rail and returning fuel to the low pressure fuel source;
• a pressure sensor for sensing fuel pressure in the common rail;
• and
• an electronic control unit for controlling operation of the high pressure fuel supply pump, the injectors and the electromagnetic pressure regulator according to engine operating conditions;
• wherein,
• fuel volume from said high pressure fuel supply pump is controlled by the electronic control unit to produce a predetermined fuel pressure in said common rail;
• and
• control of the high pressure fuel supply pump is stopped when its malfunction is sensed, and fuel injection from the injector is thereafter controlled according to fuel pressure from the low pressure fuel supply pump.

A high pressure fuel injection system for an internal combustion engine comprising:

• a low pressure fuel source;
• a low pressure fuel supply pump, connected to the low pressure fuel source, for pumping up fuel from the low pressure fuel supply source;
• a high pressure fuel supply pump, connected to the low Pressure fuel supply pump, for pressurizing fuel sent from the low pressure fuel supply pump;
• a common rail, connected to the high pressure fuel supply pump, for accumulating therein pressurized fuel sent from the high pressure fuel supply pump;
• injectors, connected to the common rail, for injecting fuel into the internal combustion engine;
• a high pressure regulator, connected to the common rail, for relieving fuel pressure in the common rail and returning fuel to the low pressure fuel source;
• a pressure sensor for sensing fuel pressure in the common rail;
• and
• an electronic control unit for controlling operation of the high pressure fuel supply pump, the injectors and the electromagnetic pressure regulator according to engine operating conditions;
• wherein,
• fuel injection from the injectors is controlled according to fuel pressure in the common rail sensed by the pressure sensor, when the high pressure regulator malfunctions in an always-open fashion.

A high pressure fuel injection system for an internal combustion engine comprising:

• a low pressure fuel source;
• a low pressure fuel supply pump, connected to the low pressure fuel source, for pumping up fuel from the low pressure fuel supply source;
• a high pressure fuel supply pump, connected to the low pressure fuel supply pump, for pressurizing fuel sent from the low pressure fuel supply pump;
• a common rail, connected to the high pressure fuel supply pump, for accumulating therein pressurized fuel sent from the high pressure fuel supply pump;
• injectors, connected to the common rail, for injecting fuel into the internal combustion engine;
• a high pressure regulator, connected to the common rail, for relieving fuel pressure in the common rail and returning fuel to the low pressure fuel source;
• a pressure sensor for sensing fuel pressure in the common rail;
• and
• an electronic control unit for controlling operation of the high pressure fuel supply pump, the injectors and the electromagnetic pressure regulator according to engine operating conditions;
• wherein,
• fuel pressure in the common tail is solely controlled by controlling the high pressure, fuel supply pump, when the high pressure regulator malfunctions in an always-closed fashion.

A high pressure fuel injection system for an internal combustion engine comprising:

• a low pressure fuel source;
• a low pressure fuel supply pump, connected to the low pressure fuel source, for pumping up fuel from the low pressure fuel supply source;
• a high pressure fuel supply pump, connected to the low pressure fuel supply pump, for pressurizing fuel sent from the low pressure fuel pump;
• a common rail, connected to the high pressure fuel supply pump, for accumulating therein pressurized fuel sent from the high pressure fuel supply pump;
• injectors, connected to the common rail, for injecting fuel into the internal combustion engine;
• a high pressure regulator, connected to the common rail, for relieving fuel pressure in the common rail and returning fuel to the low pressure fuel source;
• a pressure sensor for sensing fuel pressure in the common rail;
• and
• an electronic control unit for controlling operation of the high pressure fuel supply pump, the injectors and the electromagnetic pressure regulator according to engine operating conditions;
• wherein,
• fuel pressure in the common rail is controlled by driving the high pressure fuel supply pump according to the operating conditions of the engine without using signals from the pressure sensor, when the pressure sensor malfunctions.

A high pressure fuel injection system for an internal combustion engine comprising:

• a low pressure fuel source;
• a low pressure fuel supply pump, connected to the low pressure fuel source, for pumping up fuel from the low pressure fuel supply source;
• a high pressure fuel supply pump, connected to the low pressure fuel supply pump, for pressurizing fuel sent from the low pressure fuel supply pump;
• a common rail, connected to the high pressure fuel supply pump, for accumulating therein pressurized fuel sent from the high pressure fuel supply pump;
• injectors, connected to the common rail, for injecting fuel into the internal combustion engine;
• a high pressure regulator, connected to the common rail, for relieving fuel pressure in the common rail and returning fuel to the low pressure fuel source;
• a pressure sensor for sensing fuel pressure in the common rail;
• and
• an electronic control unit for controlling operation of the high pressure fuel supply pump, the injectors and the electromagnetic pressure regulator according to engine operating conditions;
• wherein,
• when the pressure sensor malfunctions, operation of the high pressure fuel supply pump is fixed to deliver a predetermined fuel quantity, and fuel injection from the injectors is controlled according to operating conditions of the engine.