Method of controlling an exhaust recirculation gas system
AssigneeGM Global Technology Operations LLC
InventorsAlberto Vassallo, Stefano Pellegrino, Salvatore Sannino
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Abstract
A method of controlling an exhaust gas recirculation system of an internal combustion engine is disclosed. The engine includes a compressor, an intake manifold, an after-treatment system, a low pressure EGR system and a high pressure EGR system. The method temporarily adjusts a low pressure EGR ratio, keeping constant a total EGR rate, after verifying at least one among compressor parameters, after-treatment system parameters or intake manifold parameter.
Claims13
A method of controlling an exhaust gas recirculation system for an internal combustion engine of the type having a high pressure loop coupled between an exhaust manifold and an intake manifold and a low pressure loop coupled between a point downstream from an after-treatment system and the intake manifold, the method comprising:
- verifying an operating parameter for a compressor surge condition is within a predetermined operating range and
- controlling an EGR valve to adjust a low pressure EGR ratio within a desired emission stability range while maintaining a constant total EGR rate based on verification of the operating parameter to recirculate exhaust gas from the low pressure loop and the high pressure loop wherein the LP-EGR ratio is computed as follows:
- LP-EGR ratio=LP-EGR rate/(LP-EGR rate+HP-EGR rate);
- wherein the total EGR rate is computed as follows:
- total EGR rate=LP-EGR rate+HP-EGR rate) and
- wherein LP-EGR rate is a gas flow rate through the low pressure EGR system and HP-EGR rate is a gas flow rate through the high pressure EGR system.
A method of controlling an exhaust gas recirculation system for an internal combustion engine of the type having a high pressure loop coupled between an exhaust manifold and an intake manifold and a low pressure loop coupled between a point downstream from an after-treatment system and the intake manifold, the method comprising:
- verifying, in an electronic control unit, operating parameters for a compressor surge condition, the after-treatment device and the intake manifold are within a predetermined operating range;
- and
- controlling an EGR valve with the electronic control unit, to adjust a low pressure EGR ratio within a desired emission stability range while maintaining a constant total EGR rate based on verification of the operating parameters to recirculate exhaust gas from the low pressure loop and the high pressure loop wherein the LP-EGR ratio is computed as follows:
- LP-EGR ratio=LP-EGR rate/(LP-EGR rate+HP-EGR rate);
- wherein the total EGR rate is computed as follows:
- total EGR rate=(LP-EGR rate+HP-EGR rate) and
- wherein LP-EGR rate is a gas flow rate through the low pressure EGR system and HP-EGR rate is a gas flow rate through the high pressure EGR system.
A exhaust gas recirculation system for an internal combustion engine comprising:
- an exhaust gas recirculation system including:
- a high pressure loop configured to be coupled between an exhaust manifold and an intake manifold of an internal combustion engine;
- a low pressure loop configured to be coupled between a point downstream from an after-treatment device and the intake manifold of the internal combustion engine;
- and
- an EGR valve operable to recirculate exhaust gas from a low pressure loop and a high pressure loop
- an electronic control unit and a computer program product stored in non-transitory computer readable medium having a computer-code operable with the electronic control unit to verify an operating parameter for a compressor surge condition is within a predetermined operating range;
- and
- control the EGR valve to adjust a low pressure EGR ratio within a desired emission stability range while maintaining a constant total EGR rate based on verification of the operating parameter to recirculate exhaust gas at a low pressure EGR ratio and at a total EGR rate;
- wherein the LP-EGR ratio is computed as follows:
- LP-EGR ratio=LP-EGR rate/(LP-EGR rate+HP-EGR rate);
- wherein the total EGR rate is computed as follows:
- total EGR rate=(LP-EGR rate+HP-EGR rate) and
- wherein LP-EGR rate is a gas flow rate through the low pressure EGR system and HP-EGR rate is a gas flow rate through the high pressure EGR system.
Dependencies are inferred from the claim text.