Fuel pump control system for cylinder cut-off internal combustion engine

A system for controlling a fuel pump installed in a fuel supply line connected to a fuel tank of an internal combustion engine having a plurality of cylinders and mounted on a vehicle, operation of the engine being switchable between cut-off-cylinder operating mode during which some of the cylinders are non-operative and full-cylinder operating mode during which all of the cylinders are operative, comprising:

• a fuel injector connected to the fuel supply line and supplied with fuel pressurized by the fuel pump;
• an engine operating mode discriminator discriminating whether the operation of the engine is in the full-cylinder operating mode or in the cut-off-cylinder operating mode;
• and
• a fuel pump controller controlling operation of the fuel pump based on the discriminated operating mode of the engine, the fuel pump controller further comprising:
• an engine operating index determiner determining an index that indicates operating condition of the engine;
• and
• a comparator comparing the determined index with threshold values;
• wherein the fuel pump controller controls the operation of the fuel pump such that the delivery flow rate of the fuel pump is increased/reduced based on a result of the comparison;
• and
• wherein the threshold values are made different between a case of increasing the delivery flow rate and a case of reducing the delivery flow rate.

A method of controlling a fuel pump installed in a fuel supply line connected to a fuel tank of an internal combustion engine having a plurality of cylinders and mounted on a vehicle and a fuel injector connected to the fuel supply line and supplied with fuel pressurized by the fuel pump, operation of the engine being switchable between cut-off-cylinder operating mode during which some of the cylinders are non-operative and full-cylinder operating mode during which all of the cylinders are operative, the method comprising:

• discriminating whether the operation of the engine is in the full-cylinder operating mode or in the cut-off-cylinder operating mode;
• and
• controlling operation of the fuel pump based on the discriminated operating mode of the engine,
• wherein controlling operation of the fuel pump further comprises:
• calculating a first fuel injection amount for the fuel injector installed at at least one of the cylinders that is non-operative in the cut-off-cylinder operating mode;
• calculating a second fuel injection amount for the fuel injector installed at a cylinder other than that is non-operative in the cut-off-cylinder operating mode;
• and
• controlling the operation of the fuel pump based on the first and second fuel injection amounts.

A method of controlling a fuel pump installed in a fuel supply line connected to a fuel tank of an internal combustion engine having a plurality of cylinders and mounted on a vehicle and a fuel injector connected to the fuel supply line and supplied with fuel pressurized by the fuel pump, operation of the engine being switchable between cut-off-cylinder operating mode during which some of the cylinders are non-operative and full-cylinder operating mode during which all of the cylinders are operative, the method comprising:

• discriminating whether the operation of the engine is in the full-cylinder operating mode or in the cut-off-cylinder operating mode;
• and
• controlling operation of the fuel pump based on the discriminated operating mode of the engine,
• wherein controlling operation of the fuel pump further comprises:
• determining an index that indicates operating condition of the engine;
• comparing the determined index with threshold values;
• and
• controlling the operation of the fuel pump such that the delivery flow rate of the fuel pump is increased or reduced based on a result of the comparison, and
• wherein the threshold values are made different between a case of increasing the delivery flow rate and a case of reducing the delivery flow rate.