Tomorrows Diesel Fuel Diversity - Challenges and Solutions 2008-01-1731
Regulated emissions, CO2-values, comfort, good driveability, high reliability and costs, this is the main frame for all future powertrain developments.
In this frame, the diesel powertrain, not only for passenger cars, but also for commercial vehicle applications, faces some challenges in order to fulfil the future European and current US emission legislations while keeping the fuel consumption benefit, good driveability and an acceptable cost frame.
One of these challenges is the varying fuel qualities of diesel fuel in different countries including different cetane number, volatility, sulphur content and different molecular composition. In addition to that in the future, more and more alternative fuels with various fuel qualities and properties will be launched into the market for economical and environmental reasons.
At present, the control algorithms of the injection system applied in most diesel engines is open loop control. With this approach, the varying fuel qualities will increase the difficulty and duration of calibration; at the same time, it also decreases the robustness of combustion and emissions.
A possible solution to manage the combustion with different fuels is to use a closed loop combustion control. Once this supposition is verified by engine tests, the calibrations for fuels with different qualities will become faster and easier. Also an online adaptation of the calibration during vehicle use is possible to avoid engine malfunction and assure the appropriate drivability and emission performance.
In this paper an innovative method to compensate the varying fuel qualities will be shown. Based on two typical fuel qualities already available on the market, EN590 EU Diesel and low cetane number US diesel, the combustion is analyzed to find out the influence on combustion behaviour and emissions.
Based on these data and results, an innovative closed loop combustion control strategy to compensate varying fuel qualities will be shown.