The Potential of a Separated Electric Compound Spark-Ignition Engine for Hybrid Vehicle Application

Abstract In-cylinder expansion of internal combustion engines based on Diesel or Otto cycles cannot be completely brought down to ambient pressure, causing a 20% theoretical energy loss. Several systems have been implemented recover and use this such as turbocharging, turbomechanical turbo-electrical compounding, the implementation Miller cycles. In all these cases however, amount recovered is limited allowing engine reach an overall efficiency incremental improvement between 4% 9%. Implementing adequately designed expander–generator unit could efficiently unexpanded exhaust gas improve efficiency. work, application hybrid propulsion vehicle considered, where onboard storage receives power produced by expander–generator, which hence employed for through electric drivetrain. Starting from considerations, simple but effective modeling approach used evaluate energetic potential spark-ignition (SI) electrically supercharged equipped with expander connected generator. The was compared reference turbocharged within architecture. It found that, if recovered, reduce fuel consumption related pollutant emissions 4–12%, depending output.