A method for operating an internal combustion engine, which comprises a combustion unit, a generator coupled with the combustion unit, a fresh gas tract, an exhaust tract, an exhaust gas recirculation line, which branches off of the exhaust tract and opens into the fresh gas tract, and at least one electrical heating device, which is integrated into the exhaust tract or into the exhaust gas recirculation line, characterized in that, during an overrun mode of the combustion unit, the heating device is operated with energy provided by the generator, and exhaust gas heated with the aid of the heating device is partially or completely guided via the exhaust gas recirculation line.

A system and method of exhaust gas recirculation (EGR) in an internal combustion engine are provided. The EGR system includes a first EGR flow path and a second EGR flow path independent of the first EGR flow path that are each configured to recirculate high pressure exhaust from the exhaust system back to the engine intake system. The system includes a controller in operable communication with the EGR system configured to selectively control an amount of EGR flow through at least one of the first and second EGR flow paths.

A system and method of exhaust gas recirculation (EGR) in an internal combustion engine are provided. The EGR system includes a first EGR flow path and a second EGR flow path independent of the first EGR flow path that are each configured to recirculate high pressure exhaust from the exhaust system back to the engine intake system. The system includes a controller in operable communication with the EGR system configured to selectively control an amount of EGR flow through at least one of the first and second EGR flow paths.

A thermoelectric generator for a vehicle utilizing heat of exhaust gas discharged from an engine of the vehicle includes a heat exchange unit, through which a coolant circulates, a thermoelectric generation unit for converting thermal energy of exhaust gas into electrical energy, a first flow passage for guiding the exhaust gas to pass through the heat exchange unit, a second flow passage for guiding the exhaust gas to pass through the thermoelectric generation unit, a third flow passage for guiding the exhaust gas to bypass the heat exchange unit and the thermoelectric generation unit without passing therethrough, a first valve for opening or closing the first flow passage, a second valve for selectively opening or closing the second flow passage and the third flow passage, and a driving unit for operating the first valve and the second valve by a single power source.

A thermoelectric generator for a vehicle utilizing heat of exhaust gas discharged from an engine of the vehicle includes a heat exchange unit, through which a coolant circulates, a thermoelectric generation unit for converting thermal energy of exhaust gas into electrical energy, a first flow passage for guiding the exhaust gas to pass through the heat exchange unit, a second flow passage for guiding the exhaust gas to pass through the thermoelectric generation unit, a third flow passage for guiding the exhaust gas to bypass the heat exchange unit and the thermoelectric generation unit without passing therethrough, a first valve for opening or closing the first flow passage, a second valve for selectively opening or closing the second flow passage and the third flow passage, and a driving unit for operating the first valve and the second valve by a single power source.

A method includes operating a spark ignition engine and flowing low pressure exhaust gas recirculation (EGR) from an exhaust to an inlet of the spark ignition engine. The method includes interpreting a parameter affecting an operation of the spark ignition engine, and determining a knock index value in response to the parameter. The method further includes reducing a likelihood of engine knock in response to the knock index value exceeding a knock threshold value.

A method includes operating a spark ignition engine and flowing low pressure exhaust gas recirculation (EGR) from an exhaust to an inlet of the spark ignition engine. The method includes interpreting a parameter affecting an operation of the spark ignition engine, and determining a knock index value in response to the parameter. The method further includes reducing a likelihood of engine knock in response to the knock index value exceeding a knock threshold value.

A method includes operating a spark ignition engine and flowing low pressure exhaust gas recirculation (EGR) from an exhaust to an inlet of the spark ignition engine. The method includes interpreting a parameter affecting an operation of the spark ignition engine, and determining a knock index value in response to the parameter. The method further includes reducing a likelihood of engine knock in response to the knock index value exceeding a knock threshold value.

A method includes operating a spark ignition engine and flowing low pressure exhaust gas recirculation (EGR) from an exhaust to an inlet of the spark ignition engine. The method includes interpreting a parameter affecting an operation of the spark ignition engine, and determining a knock index value in response to the parameter. The method further includes reducing a likelihood of engine knock in response to the knock index value exceeding a knock threshold value.

Methods and systems for maintaining a temperature of catalyst above a threshold temperature during vehicle braking and coasting is described. In one example, engine pumping work may be increased without increasing flow of cool fresh air through the engine's exhaust system to provide a desired level of engine braking. The net air flow through the engine may be reduced via activating a decompression actuator.