Servojet Products International

Clean Air Power, Inc.

N John Beck

Kresimir Gebert

Hoi Ching Wong

William P Johnson

Shui-Chi Li

EGR mass fraction or a value indicative thereof can be calculated based on temperature measurements rather than mass flow and/or pressure measurements, hence negating the need for expensive and relatively unreliable measurement devices in an active EGR system for an internal combustion engine. The EGR system may be a low pressure EGR system configured to direct cooled, filtered EGR to the engine's air intake system using an effective, simple venturi and/or a continuously regenerated catalytic particulate trap. The resultant system can reduce NOx emissions in a diesel engine on the order of 50% and approximately 90% for CO, HC, and PM. NOx and other emissions can be reduced still further when the EGR system is combined with other pretreatment and/or after treatment devices. Many components of the low pressure EGR system are also usable in a passive EGR system.

EGR control system and method for an internal combustion engine

The performance of a compression ignition internal combustion engine is improved by optimizing a cylinder pressure-dependent parameter on a full time, full range basis using in-cylinder pressure measurements to determine the actual value of the parameter to be optimized. The basic procedure is to determine the desired or optimum value of the parameter, determine the actual value of the parameter or a related parameter, and then adjusting an engine operating characteristic such as air/fuel ratio to maintain the controlled parameter at its optimum value. The preferred parameter is a cylinder pressure ratio (CPR) obtained by dividing first and second values of cylinder pressure, and sensed at different points in a thermodynamic cycle, by one another. The sensed values are preferably a first value P , obtained during the compression stroke, and a second value P , obtained after combustion is complete. Direct in-cylinder pressure measurements can also be used for other purposes such as knock detection, determination of maximum cylinder pressure (MCP), and engine controls dependent thereon.

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Bonita, CA, United States of America

N John Beck