Fluid pump control apparatus and method

A fluid pump control apparatus for pumping pressurized fluid from a fluid pump to a pressure accumulating chamber connected to a fluid injection valve of an internal combustion engine, the fluid pump control apparatus comprising:

• a feedback control means for setting a fluid pumping amount to be pumped by the fluid pump on a basis of a target value of pressure in the pressure accumulating chamber and an actual pressure in the pressure accumulating chamber, in such a manner that the actual pressure in the pressure accumulating chamber becomes substantially equal to the target value of pressure;
• and
• a prediction means for calculating a pressure in the pressure accumulating chamber that occurs before starting a next fluid pumping operation, on a basis of fluid injection amount, a fluid pumping amount, and a pressure in the pressure accumulating chamber occurring before starting a present fluid pumping operation,
• wherein the feedback control means uses the predicted pressure in the pressure accumulating chamber predicted by the prediction means, instead of the actual pressure in the pressure accumulating chamber, to set a fluid pumping amount to be pumped by the next fluid pumping operation wherein an entire required fluid pumping amount not supplied by a first fluid pumping stroke, is carried over to be supplied by a next fluid pumping stroke by summing the carried-over amount of fluid in combination with a base fuel pumping amount.

A fluid pump control method for pumping fluid from a fluid pump to a pressure accumulating chamber that holds pressurized fluid, comprising:

• setting a basic fluid pumping amount to be pumped by the fluid pump on a basis of a target value of pressure in the pressure accumulating chamber;
• calculating a required fluid pumping amount required to adjust pressure in the pressure accumulating chamber from a present pressure to the target value of pressure;
• setting a sum of a total required amount of fluid that includes the required fluid pumping amount calculated in the calculating step, and the basic fluid pumping amount of the fluid pump set on a basis of the target value of pressure, as a set value of a fluid pumping amount to be pumped by the fluid pump;
• and
• setting a carried-over amount by which the set value of the fluid pumping amount exceeds a predetermined fluid amount of the fluid pump, the carried-over amount being carried over to a next setting of the fluid pumping amount, if the set value of the fluid pumping amount exceeds the predetermined fluid pumping amount such that if an entire required fluid pumping amount cannot be supplied by a first fluid pumping stroke, then that amount of fluid not supplied is carried over to be supplied by a next fluid pumping stroke by summing the carried-over amount of fluid in combination with a base fuel pumping amount.

A fluid pump control method for pumping pressurized fluid from a fluid pump to a pressure accumulating chamber connected to a fluid injection valve of an internal combustion engine, the fluid pump control method comprising:

• setting a fluid pumping amount to be pumped by the fluid pump through feedback control on a basis of a target value of pressure in the pressure accumulating chamber and an actual pressure in the pressure accumulating chamber, in such a manner that the actual pressure in the pressure accumulating chamber becomes substantially equal to the target value of pressure and such that if an entire required fluid pumping amount cannot be supplied by a first fluid pumping stroke, then that amount of fluid not supplied is carried over to be supplied by a next fluid pumping stroke by summing the carried-over amount of fluid in combination with a base fuel pumping amount;
• and
• predicting a pressure in the pressure accumulating chamber that occurs before starting a next fluid pumping operation, on a basis of a fluid injection amount, the fluid pumping amount, and a pressure in the pressure accumulating chamber that occurs before starting a present fluid pumping operation,
• wherein the predicted pressure in the pressure accumulating chamber predicted in the predicting step is used to generate feedback, instead of the actual pressure in the pressure accumulating chamber, to set the fluid pumping amount to be pumped by the next fluid pumping operation.