Simulation and Control of Combustion in Military Diesel Engines

Project duration 2017-2018

The control of military diesel engines to operate on fuels of different physical and chemical properties requires simulation models that would expedite the development of strategies for the ECU (Engine Control Unit) to adjust different engine systems to achieve the goals of improved fuel economy, high power density without the emission of visible black, and reliable prompt cold start without the emission of white smoke. Such goals are important for survivability, mobility and mission readiness in the field. These goals are different from those of commercial engines which operate on fuels with narrow specifications and are equipped with elaborate and bulky after treatment devices required to meet stringent emission standards. Therefore, there is a need to develop different strategies for military engines ECUs to enable them to operate on fuels of wide specifications and meet the military goals under the severe environment of the field.

The two main objectives are:

• Develop strategies, based on computer simulations and experimental investigations, for diesel engines to operate properly on different military fuels under a wide range of ambient temperatures and achieve the following with sustained improvements in fuel economy:
• High power with reduced soot emissions by controlling the fuel and air systems.
• Reduced noise and vibration by controlling the rates of pressure rise and peak cylinder gas pressures particularly when using volatile low centane number (CN) fuels, such as low CN JP-8, that have long ignition delay periods.
• Prompt cold start to reduce loss of fuel in long cranking periods, and to reduce combustion instability and the emission of white smoke.
• Develop a data bank for the autoignition and combustion characteristics of JP-8 under cold starting and warmed up operating conditions.  The data will be used for the calibration and validation of the detailed combustion mechanisms and surrogates under development in Thrust Area 4 for JP-8.  The CN for JP-8 varies between 25 and 65.

Publications from prior work:

• Jayakumar, C., Nargunde, aj., Sinha, A., Bryzik, W.,  Henein, N. A. And Sattler, E., 2012, “Effect of Biodiesel, Jet Propellant (JP-8) and Ultra Low Sulfur Diesel Fuel on Autoignition, Combustion,  Performance and Emissions in a  Single-Cylinder Diesel Engine,” ASME J. Eng.  Gas Turbines 134(2), 022801, 2012.
• Jayakumar, C., Nargunde, A., Sinha, A., Bryzik, W.,Henein, N. A. And Sattler, E.,”2012,” Effect of Swirl and Injection Pressure on Performance and Emissions  of JP-8 Fueled High Speed Single Cylinder Diesel engine,” ASME J. Eng.  Gas Turbines 134(2), p 022802, 2012.