The United States of America As Represented by the Administrator of the U.S. Environmental Protection Agency

The United States of America As Represented by the Environmental Production Agency

Mark Stuhldreher

Charles L Gray, Jr

David James Haugen

Andrew James Moskalik

A hydraulic brake system includes a piston that separates a first pressure chamber from a second pressure chamber of a cylinder bore. A valve within a piston bore is movable between three positions. In the first position, the first and second pressure chambers are in fluid communication with a low-pressure fluid supply; in the second position, the second pressure chamber is isolated from the first pressure chamber and the low-pressure fluid supply; in the third position, a high-pressure fluid supply is in fluid communication with the second pressure chamber, allowing high-pressure fluid to flow into the second pressure chamber. High pressure in the second pressure chamber moves the boost piston, applying boosted braking pressure to a vehicle brake. Pressure in the second chamber against a surface of the valve biases the valve toward the first position. An accumulator stores pressurized fluid and provides the high-pressure fluid supply, enabling on-demand brake boosting force during engine-off operation of a hybrid vehicle.

On-demand power brake system and method

A center-closed power steering system provides power steering assistance in engine-off conditions for reduced fuel consumption. The power steering system includes a hydraulic pump mechanically driven by the engine, a high pressure accumulator, a steering gearbox fluidly connected to the accumulator, and a center closed valve mechanically connected to a driver-operated steering wheel. The valve is configured to selectively control flow of pressurized fluid from the accumulator to the steering gearbox to provide power steering assistance. The inner shaft of the rotary center-closed valve is provided with a cavity with V-shaped notches on the transition surfaces on lands configured to sealingly engage the inner surface of the valve outer sleeve, in order to provide a smooth transition in flow for power steering assistance, and a better driver feel.

Engine-off power steering system

A common rail intensifier fuel injection system includes a plurality of fuel injectors respectively associated with cylinders of an internal combustion engine. A common rail supplies fuel at an intensified pressure to the fuel injectors and receives the fuel at the intensified pressure, alternately, from at least two fuel pressure intensifying circuits. At least one of the fuel pressure intensifying circuits includes a fuel pressure intensifier having an operating chamber for receiving and discharging an operating fluid, and a fuel chamber of a diameter smaller than that of the operating chamber for receiving fuel at a low pressure from the fuel supply and discharging the fuel at the intensified pressure into one of the fuel pressure intensifying circuits. A control valve, in a first position, connects the operating fluid source with the operating chamber of the fuel pressure intensifier and, in a second position, connects the operating chamber of the fuel pressure intensifier with a drain. A controller switches the control valve between the first and second positions and switches the supply of fuel at the intensified pressure, to the common rail, between the various fuel pressure intensifying circuits.

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Pinckney, MI, United States of America

Mark Stuhldreher