Abstract: A system for braking the wheels of a hydraulic hybrid vehicle includes a brake pedal having a range of pedal displacement including a deadband displacement range, an accumulator containing fluid at relatively high pressure, a reservoir containing fluid at lower pressure, a pump/motor having variable volumetric displacement connected to the accumulator and reservoir, and driveably connected to the wheels; a system responsive to brake pedal displacement in the deadband range for placing the pump/motor in a pump state wherein the pump/motor is driven by the wheels and pumps fluid from the reservoir to the accumulator; and a control valve for changing the volumetric displacement of the pump/motor in response to displacement of the brake pedal.

Abstract: A system for a hydraulically driven vehicle includes a pump producing fluid flow at an outlet, pump-motors having variable flow rates for driving the wheels, a hydraulic rail having a pressure and connecting the pump and the pump-motors, sensors producing signals representing rail pressure, pump-motor speed, pump-motor displacement, and a controller for determining a target hydraulic system parameter, determining, based at least in part on the flow rate of the pump-motor, rail pressure, and a flow rate produced by the engine-pump, a flow rate produced by the engine-pump that is required to produce the target system parameter, and adjusting an engine operating parameter of a cylinder-pump bank such that the demanded magnitude of the system parameter is produced.

Abstract: A system for transmitting power hydraulically to and from the wheels of a motor vehicle includes an accumulator containing fluid at relatively high pressure, a reservoir containing fluid at lower pressure, and a pump/motor driveably connected to the wheels and having a variable volumetric displacement for pumping fluid between the accumulator and the reservoir. A first circuit connects the inlet to the reservoir and the outlet to the accumulator. A second circuit includes a first path having a low flow rate capacity, a second path having a higher flow rate capacity. A controller switches between pumping operation and motoring operation, opens and closes the first path during motoring operation, and reduces the displacement before switching between pumping operation and motoring operation.

Abstract: A powertrain for transmitting power in a vehicle includes a prime mover having a relatively slow transient response, and a storage device for storing energy in a predetermined form. A transmission includes an input driveably connected to the prime mover and an output driveably connected to vehicle drive wheels, producing a range of ratios of a speed of the output to a speed of the input that varies from negative to positive and includes zero. An energy conversion device, driveably connected to the prime mover and drive wheels, converts rotational power transmitted to the energy conversion device from the wheels and the prime mover to a form of energy that can be stored in the storage device, and drives the wheels using energy supplied to the energy conversion device from the storage device. A control device alternately transmits energy from the storage device to the energy conversion device, and transmits energy from the energy conversion device to the storage device.

Abstract: A system according to this invention for transmitting power hydraulically to and from the wheels of a motor vehicle includes an accumulator containing fluid at relatively high pressure, a reservoir containing fluid at lower pressure, and a pump/motor driveably connected to the wheels and having an inlet, an outlet, and a variable volumetric displacement for pumping fluid between the accumulator and the reservoir. A first circuit connects the inlet to the reservoir and the outlet to the accumulator. A second circuit, which connects the inlet to the accumulator and the outlet to the reservoir, includes a first path having a low flow rate capacity, a second path having a higher flow rate capacity. A controller switches between pumping operation and motoring operation, opens and closes the first path during motoring operation, and reduces the displacement before switching between pumping operation and motoring operation.

Abstract: A system for braking the wheels of a hydraulic hybrid vehicle includes a brake pedal having a range of pedal displacement including a deadband displacement range, an accumulator containing fluid at relatively high pressure, a reservoir containing fluid at lower pressure, a pump/motor having variable volumetric displacement connected to the accumulator and reservoir, and driveably connected to the wheels; a system responsive to brake pedal displacement in the deadband range for placing the pump/motor in a pump state wherein the pump/motor is driven by the wheels and pumps fluid from the reservoir to the accumulator; and a control valve for changing the volumetric displacement of the pump/motor in response to displacement of the brake pedal.

Abstract: A system for a hydraulically driven vehicle includes a pump producing fluid flow at an outlet, pump-motors having variable flow rates for driving the wheels, a hydraulic rail having a pressure and connecting the pump and the pump-motors, sensors producing signals representing rail pressure, pump-motor speed, pump-motor displacement, and a controller for determining a target hydraulic system parameter, determining, based at least in part on the flow rate of the pump-motor, rail pressure, and a flow rate produced by the engine-pump, a flow rate produced by the engine-pump that is required to produce the target system parameter, and adjusting an engine operating parameter of a cylinder-pump bank such that the demanded magnitude of the system parameter is produced.