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Engine simulation based on one-dimensional gas dynamics is well suited for integration of all aspects arising in engine and powertrain developments. Commonly used turbocharger performance maps in engine simulation are measured in non-pulsating flow and without taking into account the heat transfer. Since on-engine turbochargers are exposed to pulsating flow and varying heat transfer situations, the maps in the engine simulation, i.e. GT-POWER, have to be shifted and corrected which are usually done by mass and efficiency multipliers for both turbine and compressor. The multipliers change the maps and are often different for every load point. Particularly, the efficiency multiplier is different for every heat transfer situation on the turbocharger. The aim of this paper is to include the heat transfer of the turbocharger in the engine simulation and consequently to reduce the use of efficiency multiplier for both the turbine and compressor.

Spray and mixture formation in a compression-ignition engine is of paramount importance in the diesel combustion process. In an engine transient, when the load increases rapidly, the combustion system needs to handle low λ operation without producing high NOx emissions and large amounts of particulate matter. By changing the in-cylinder flow, the emissions and engine efficiency are affected. Optical engine studies were therefore performed on a heavy-duty engine geometry at different fuel injection pressures and inlet airflow characteristics. By applying different inlet port designs and valve seat masking, swirl and tumble were varied. In the engine tests, swirl number was varied from 2.3 to 6.3 and the injection pressure from 500 to 2500 bar. To measure the in-cylinder flow around TDC, particle image velocimetry software was used to evaluate combustion pictures. The pictures were taken in an optical engine using a digital high-speed camera.

Diesel Dual Fuel, DDF, is a concept where a combination of methane and diesel is used in a compression ignited engine, maintaining the high compression ratio of a diesel engine with the resulting benefits in thermal efficiency. Attention has recently been drawn to the fact that the tip of the diesel injector may reach intolerable temperatures. The high injector tip temperatures in the DDF engine are caused by the reduction in diesel flow through the injector. For dual fuel operation, as opposed to diesel, high load does not necessarily imply a high flow of diesel through the injector nozzle. This research investigated the factors causing high injector tip temperatures in a DDF engine and the underlying mechanisms which transfer heat to and from the injector tip. Parameter sweeps of each influential parameter were carried out and evaluated. In addition to this, a simple and useful model was constructed based on the heat balance of the injector tip.