Hybrid control method for fuel pump using intermittent recirculation at low and high engine speeds
First Claim
1. In a fuel supply system for an internal combustion engine, a method for controlling fuel quantity delivery from a high pressure, reciprocating piston, engine-driven fuel pump to a high pressure common rail having a plurality of fuel injection nozzles for injecting fuel into the cylinders of the engine, comprising:
- establishing at least two control regimes corresponding to a respective low engine speed pump operation and high engine speed pump operation;
during the control regime for low speed operation, feeding unregulated low pressure fuel to the pumping pistons and at a location between the pumping pistons and the common rail, diverting excess fuel discharged from the pumping pistons to a location of relatively low pressure in the fuel supply system, upstream of the pumping pistons; and
during the control regime for high-speed operation, regulating the quantity of low pressure feed fuel pressurized by the pumping pistons and delivering all of the fuel discharged from the pumping pistons, to the common rail.
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Accused Products
Abstract
In a fuel supply system for an internal combustion engine, a method for controlling fuel quantity delivery from a high pressure, reciprocating piston, engine-driven fuel pump to a high-pressure common rail having a plurality of fuel injection nozzles for injecting fuel into the cylinders of the engine. At least two control regimes are established corresponding to a respective low engine speed pump operation and high engine speed pump operation. During low speed operation, unregulated low pressure fuel is fed to the pumping pistons and at a location between the pistons and the common rail, excess fuel discharged from the pistons is diverted to a location of relatively low pressure in the fuel supply system, upstream of the pistons. During high-speed operation, the quantity of low pressure feed fuel pressurized by the pumping pistons is regulated and all of the fuel discharged from the pistons is delivered to the common rail.
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Citations
21 Claims
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1. In a fuel supply system for an internal combustion engine, a method for controlling fuel quantity delivery from a high pressure, reciprocating piston, engine-driven fuel pump to a high pressure common rail having a plurality of fuel injection nozzles for injecting fuel into the cylinders of the engine, comprising:
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establishing at least two control regimes corresponding to a respective low engine speed pump operation and high engine speed pump operation;
during the control regime for low speed operation, feeding unregulated low pressure fuel to the pumping pistons and at a location between the pumping pistons and the common rail, diverting excess fuel discharged from the pumping pistons to a location of relatively low pressure in the fuel supply system, upstream of the pumping pistons; and
during the control regime for high-speed operation, regulating the quantity of low pressure feed fuel pressurized by the pumping pistons and delivering all of the fuel discharged from the pumping pistons, to the common rail. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. In a fuel supply system for an internal combustion engine, having a fuel tank, a low pressure fuel feed line for delivering low pressure fuel to an inlet passage of a reciprocating piston, engine-driven fuel pump, the pistons receiving fuel in a charging phase from a charging chamber fluidly connected to the inlet passage and discharging high pressure fuel in a discharge phase into a discharge line for delivering high pressure fuel to a common rail having a plurality of fuel injection nozzles for injecting fuel into the cylinders of the engine, a one-way check valve situated in the discharge line between the pistons and the common rail, and a control valve operatively connected between the piston and the check valve for diverting excess fuel discharged from the piston, to the pump inlet passage, a method for controlling fuel quantity delivery to the common rail, comprising:
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establishing at least two control regimes corresponding to a respective low engine speed pump operation and high engine speed pump operation;
during low speed operation, feeding unregulated low pressure fuel to the charging chamber of the pistons and at a location between the pistons and the common rail, operating said control valve between nozzle injection events to divert excess fuel discharged from the pistons, to said pump inlet passage, thereby establishing an intermittent low pressure recirculation circuit through the pump; and
during high speed operation, operating said control valve between piston discharges to regulate the quantity of low pressure feed fuel to the charging chamber and delivering all of the fuel discharged from the pistons, to the common rail. - View Dependent Claims (19, 20, 21)
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Specification