Method and apparatus for exhaust gas recirculation control and power augmentation in an internal combustion engine

An exhaust gas recirculation control and power augmentation system for a heavy-duty diesel engine having an intake manifold and an exhaust manifold comprising:

• a turbocharger having a compressor for supplying intake air to the intake manifold connected with a turbine which receives exhaust gas from the exhaust gas manifold to operate the compressor;
• the turbine having an outlet coupled with a filter trap whereby exhaust gas exiting from the turbine will flow through the filter trap to substantially reduce particulate matter in the exhaust gas;
• an exhaust gas recirculation line extending from the outlet of the filter trap to an electronically controlled diverter valve;
• an intake air filter having a first air flowline to supply intake air to the compressor of the turbocharger;
• a second air flowline extending from the intake air filter to supply intake air to the electronically controlled diverter valve;
• the electronically controlled diverter valve having a first inlet to receive recirculated exhaust gas from the exhaust gas recirculation line and a second inlet to receive intake air from the second air flowline;
• the electronically controlled diverter valve having an outlet coupled with an electrically driven compressor whereby the electronically controlled diverter valve controls the volume and ratio of recirculated exhaust gas and intake air supplied to the electrically driven compressor;
• and
• the electrically driven compressor having an outlet connected with the intake manifold to supply a mixture of recirculated exhaust gas and intake air to the intake manifold.

A method for controlling exhaust gas recirculation and power augmentation of a diesel engine having a turbocharger, an intake manifold and an exhaust manifold comprising:

• supplying intake air to a compressor portion of the turbocharger;
• supplying intake air to an electronically controlled diverter valve;
• directing exhaust gas from the exhaust gas manifold to a turbine portion of the turbocharger;
• filtering exhaust gas exiting from the turbine portion of the turbocharger and directing a first portion of the filtered exhaust gas to the electronically controlled diverter valve;
• mixing the first portion of the filtered exhaust gas with the intake air supplied to the electronically controlled diverter valve;
• directing the mixture of filtered exhaust gas and intake air from the electronically controlled diverter valve to an electrically driven compressor;
• discharging the mixture of filtered exhaust gas and intake air from the electrically driven compressor to the intake manifold;
• and
• adjusting the ratio of intake air and filtered exhaust gas exiting from the electronically controlled diverter valve based in part on the speed of the engine and desired NO.sub.x emission level.