Infl uence of Low-Speed Marine Diesel Engine Settings on Waste Heat Availability

The low-speed marine diesel engine is the most effective of all the ship propulsion systems. On every ship there is a need for thermal energy besides mechanical power to drive the propeller.It is possible to install a heat exchanger in the exhaust system that makes use of waste heat of the exhaust gasses of the diesel engine. Such a combined mechanical and thermal energy generation is called cogeneration. Modern engines allow the variation of the fuel injection timing and the variation of the exhaust valve timing, which results in a great usage fl exibility. In the current work a computer simulation model of a low-speed marine diesel engine is presented. The exhaust gas heat energy available to power a heat exchanger was calculated. The time of the beginning of fuel injection and the time of the opening of the exhaust valve was varied. It was analyzed how these parameters infl uence the power, the fuel consumption, the engine efficiency, the exhaust gas temperature, the heat energy available in the exhaust gasses, the overall effi ciency of the cogeneration system, and the power to heat ratio.