Simulation-Based Cold-Start Control Strategy for a Diesel Engine with Common Rail Fuel System at Different Ambient Temperatures 2007-01-0933

A new tool has been used to arrive at appropriate split injection strategy for reducing the cranking period during the cold start of a multi-cylinder engine at decreasing ambient temperatures. The concept behind this tool is that the combination of different injection parameters that produce the highest IMEP should be able to improve the cold startability of the diesel engine. In this work the following injection parameters were considered: 1) injection timing, 2) split injection fraction, 3) dwell time and 4) total fuel mass injected per cycle. A commercial engine cyclic simulation code has been modified for diesel engine cycle simulation at lower ambient temperatures. The code was used to develop IMEP control maps. The maps were used to identify the parameters that would give the best IMEP. The strategies that have been identified have been validated experimentally in a multi-cylinder diesel engine equipped with a common rail fuel injection system. The simulation-based strategy proved to be very effective in improving cold start of the diesel engine at ambient temperature as low as -10°C. At temperatures lower than -10°C, the simulation-based strategies don't predict the engine failure to start. The reasons for such failure are analyzed in a sister paper published at the same conference.