Search Results

When a vehicle is subjected to a transient torque event by its engine, the powertrain usually responds in an oscillatory manner. This is a characteristic of the system, due to the lashes and the stiffness. This oscillatory behavior disturbs the driver/passengers when showing high amplitude and/or a determined frequency. The powertrain calibration must act to attenuate oscillations in order to avoid driveability issues. One approach is to modulate the spark advance to absorb the oscillatory response. This paper proposes a method to calibrate this 3rd order high pass filter algorithm, making it less time consuming than a pure empirical and trial and error manner. Benefits of 80% reduction of time consumption were obtained by applying the proposed methodology. Besides that, for the same time invested, better results were achieved with the system presenting more robust responses over the vehicle operating ranges.

Misfire monitoring is currently a mandatory On Board Diagnostic (OBD) regulatory requirement in most of the main automotive markets. The most common method used for misfire detection is the one based on the calculation of the derivative of the angular crankshaft velocity in which sharp variations of the derivative signal are associated to misfire events. Therefore, the misfire detection calibration is practically unique for a given engine hardware and installation. Within this context, this Paper will present a practical evaluation and also a computational simulation of the impact of an engine hardware change (front end accessory drive dumpers) on the calculated angular acceleration signal and, therefore, on the overall misfire detection capability. The outcomes of this study will ultimately define the need of calibration changes as well as support a future development of an analytical method to predicted impacts in misfire calibration.