Ion current detection in a diesel engine fueled with commercial diesel fuel: positively polarized ion-probe faced to piston bowl center

In this report the results of an experimental study carried out on a 3-cylinder diesel engine running at dierent speed and load conditions are presented. Experiments were mainly aimed to investigating on possible information on combustion development obtainable from ionization current detected by an electrically polarized sensor during combustion. The engine is equipped with an in-cylinder pressure sensor mounted in a glow-plug adapter; furthermore, a three-axis linear accelerometer is mounted on engine block in proximity of the same instrumented cylinder. Signals are sampled and stored via a powerful time-based data acquisition system that allows to acquire a continuous series of engine cycles at high sampling rate. The engine was controlled by an own commercial control unit.