Engine control based on flow rate and pressure for hydraulic hybrid vehicle

The method of 2, wherein the step of determining a flow rate of the engine that would produce a target line pressure within a predetermined period further comprises:

• determining a current line pressure;
• determining a target line pressure;
• determining a length of a period in which to change the current line pressure to the target line pressure;
• and
• determining, based on a difference between the current line pressure and a target line pressure, an engine-pump flow rate that would produce the target line pressure within the length of the determined period.

The method of 5, wherein the step of determining a flow rate of the engine that would produce a target line pressure within a predetermined period further comprises:

• determining a current line pressure;
• determining a target line pressure;
• determining a length of a period to change the current line pressure to the target line pressure;
• and
• determining, based on a difference between the current line pressure and a target line pressure, an engine-pump flow rate that would produce the target line pressure within the length of the determined period.

A system for transmitting power to the wheels of a vehicle comprising:

• an engine having an engine operating parameter, including multiple, selectively operating cylinder-pump banks for producing fluid flow at an outlet;
• a pump/motor having a variable flow rate including an inlet, for driving the wheels;
• a hydraulic line having a line pressure, connecting the outlet and the inlet;
• and
• means for determining a target hydraulic system parameter, means for determining, based at least in part on the flow rate of the pump/motor and a flow rate produced by each engine cylinder bank, a number of operating cylinder-pump banks that is required to produce the target hydraulic system parameter, and in response to determining the required number of operating cylinder-pump banks, means for adjusting an engine operating parameter of a cylinder-pump bank such that the required number of cylinder-pump banks operate.