Performance and refinement are key factors which influence the market acceptance of passenger cars, and consequently in the area of diesel fuel injection control there is increasing pressure for improved driveability.
“Driveline shunt” is one important and problematic aspect of driveability, which is also known as “judder”, “chuggle” or “cab-nod”. It has been defined as an objectionable vehicle oscillation which takes place following a rapid throttle input or increase in engine load. This phenomenon is caused by driveline vibrations which can occur as a consequence of variations in engine torque demand.
Mathematical modelling and experimentation techniques have been used to establish the behaviour of a fuel injection system, engine and vehicle driveline. Vehicle tests have been conducted in order to relate objective metrics and subjective opinion. Robust neo-classical design techniques have then been used to develop a controller that can be designed and tuned with due regard to physical understanding.
Early experimental results, obtained from a vehicle fitted with the Lucas Diesel Systems Common Rail fuel injection system, will illustrate the effectiveness of the above-mentioned “model-based” control strategy. Moreover, this paper will demonstrate a good control design and product design approach that is focused toward customer demand.