Coordinated Electric Supercharging and Turbo-Generation for a Diesel Engine

This paper proposes an electrical supercharging and turbo-generation system that overcomes some of these limitations. The system decouples the activation of the air compression and exhaust-energy recovery functions using a dedicated electrical energy storage buffer. Its main attributes fast speed of response to load changes and flexibility of control. A causal simulation model of the proposed system, including that of the Diesel engine, electrically driven compressor, energy buffer battery and power electronics, and the turbo-generation system are developed and analyzed. A coordinated control scheme is then implemented for the electric compressor and turbo-generator considering load demand fluctuations on the engine and enforcing battery state of charge constraints. The proposed system is evaluated on standard test cycles and compared with conventional turbo-chargers. The results show the potential of the system in improving transient performance, in general, and the cycle equivalent fuel efficiency over a standard city driving cycle.