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

David James Haugen

Charles L Gray, Jr

Mark Stuhldreher

A shut off valve is configured to shut off flow from the high pressure fluid line to the high pressure accumulator in a series hydraulic hybrid vehicle in order to quickly raise system pressure in the high pressure fluid line and enable additional torque output from the hydraulic motor for vehicle propulsion. A pressure relief valve is further provided to vent excess flow from the high pressure line to the high pressure accumulator as needed to avoid exceeding a maximum desired system pressure in the high pressure fluid line, thereby providing for safe and efficient hydrostatic operation in the vehicle.

Hydraulic hybrid vehicle with safe and efficient hydrostatic operation

A turbocharger system includes first and second turbines arranged such that exhaust gas passes through the first turbine then the second turbine. A bypass channel is configured such that exhaust gas entering the channel passes only through the second turbine. A valve positioned in the bypass channel regulates the flow of gas therethrough. The valve accelerates a stream of gas and focuses the stream toward the second turbine such that a large part of the added velocity of the stream is preserved as it enters the second turbine. Operation of the valve may be controlled so as to maintain the valve in a closed position while exhaust gas pressure above the first turbine pressure is below a first threshold, to progressively open the valve as the pressure increases above the first threshold, and to maintain the valve in a full-open position while the pressure is above a second threshold.

Efficient bypass valve for multi-stage turbocharging system

A variable displacement engine comprises two engine modules fed from a common fuel source, each engine module having an individual crankshaft. The first engine module has a high compression ratio (e.g., greater than 13:1), while the second module has a typical compression ratio for a gasoline engine (e.g., between 9:1 and 11:1). In one embodiment, the first engine module operates through high efficiency optimized alcohol fuel combustion when the fuel content exceeds a minimum alcohol content. In an alternative embodiment, the first engine module operates at high efficiency through gasoline HCCI combustion when conditions permit. When operating conditions do not permit the first engine module to operate at high efficiency, the second engine module operates as the primary engine module, with the first engine module available to provide supplemental power (at less than optimal efficiency) if needed to meet driver demand.

Two mode dual crankshaft engine

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 flex fuel internal combustion engine system includes means for sensing ethanol concentration of the fuel. If the ethanol concentration is determined to be above a given threshold, engine operation is adjusted for lean combustion of the fuel. An aftertreatment system is provided to remove harmful emissions from the exhaust.

Flex fuel internal combustion engine system

A two-volute low pressure turbocharger is provided with a VGT mechanism in one turbine volute only.

Dual volute turbocharger

Improved transient response times are obtained while maintaining low emissions with a low pressure EGR system through methods for quickly obtaining a desired oxygen concentration for charge-air to be used for combustion. Under a first method, fuel quantity in the main combustion event is controlled in the combustion process to produce exhaust around a relatively constant target exhaust oxygen concentration value. By keeping the exhaust oxygen concentration levels at a relatively constant value, lag time in waiting for low pressure EGR valve adjustments during transients may be avoided, and the system's air handling response to meet transients may be paced solely by adjusting the mass of air to be supplied (i.e. boost response). Under a second method, a multiple-stage combustion process is utilized, in which fuel feed is controlled in a small, preliminary HCCI-type combustion event in order to produce a target oxygen concentration of charge-air to be used for the second, main combustion event. Under a third method, exhaust rebreathing is used to produce a target oxygen concentration of charge-air to be used for combustion.

Control methods for low emission internal combustion system

A multi-stage turbocharging system recovers exhaust energy that is conventionally lost in bypassing exhaust flow from one stage to another in a multi-stage turbocharging system. The exhaust energy is preserved through converting a portion of the exhaust energy of the bypassed flow from pressure to kinetic energy (velocity) by passing the bypassed flow through a VGT vane outlet or other variable geometry valve/nozzle, and then not allowing the accelerated flow to dissipate energy before reaching the subsequent stage's turbine wheel, where the accelerated flow may then be converted to a mechanical rotational force by the lower pressure turbine's wheel.

Multi-stage turbocharging system with efficient bypass

This invention sets forth a commercially viable diesel combustion system that meets environmentally acceptable levels of NOx emissions (i.e. 0.2 g/bhp-hr or lower across a full map of engine speeds and loads) without the need for use of NOx aftertreatments, and simultaneously maintains engine-out PM emissions relatively close (e.g. with smoke levels at or below 3 BSN) to environmentally acceptable PM post-aftertreatment levels. The invention achieves these results by operating within a unique combination of parameters. These parameters comprise: (1) charge-air oxygen concentration below 16%, preferably between 10% and 15%, more preferably between 11% and 14%, and most preferably between 12% and 13.5% for virtually all engine operating conditions (but not necessarily at no-load or low load conditions), (2) fuel injection pressures at or exceeding 1800 bar, preferably exceeding 2100 bar, more preferably exceeding 2300 bar, and most preferably exceeding 2500 bar, at most engine speeds and loads, and (3) charge-air mass/fuel mass ratio between 25:1 and 45:1 for medium and high loads. Furthermore, the system is preferably run continuously slightly lean of stoichiometry, providing just enough excess oxygen to facilitate completeness of combustion and to maintain an exhaust oxygen level sufficient for continuous trap regeneration at a balance point in operation.

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Ann Arbor, MI, United States of America

David James Haugen