Electric Turbocharging for Energy Regeneration Increased Efficiency at Real Driving Conditions.
The demand for low fuel consumption and CO2 generation vehicles over the last few years has popularly increased the necessity of downsizing and increasing the overall thermal efficiency of Internal Combustion (IC) engines. Modern downsized internal combustion engines benefit from high-efficiency turbocharging systems for increasing their volumetric efficiency. However, despite the efficiency increase, turbochargers often lack fast transient response due to the nature of the energy exchange with the engine which deteriorates the vehicle’s drivability. An electrically-assisted turbocharger can be used for improving the transient response without any parasitic losses to the engine while providing energy recovery to increase overall system efficiency.
The present study provides a detailed numerical investigation on the potential of e-turbocharging to control load and if possible, replace wastegate valve. A parametric study of the optimum compressor/turbine sizing and wastegate area was performed for maximum torque, fast response time and energy regeneration across the real driving conditions speed/load area of the engine
The results showed that the implementation of a motor-generator can contribute to reducing the response time of the engine by up to 90% while improving its thermal efficiency and generating up to 1kWh of energy. Suppressing the wastegate can only be achieved when a larger turbine is implemented which as a result deteriorates the engine’s response and leads to energy provision demands at low engine speeds.