An Analytical Approach to Using the Vibration Signal to Determine Combustion Characteristics of Homogeneous Charge Compression Ignition Engines

Abstract

Homogeneous charge compression (HCCI) ignition is a low-temperature combustion technique for low-emission combustion engines. Measurement of vibration is a non-intrusive alternative to in-cylinder pressure measurement, and can enable combustion control. This study proposes a phenomenological-based approach to determine essential combustion parameters from vibration data. The experiments were performed using a single-cylinder research engine with an accelerometer attached to the engine head. The engine operation envelope covered the whole engine’s operating area. The peak acceleration and its crank angle were selected for correlation-seeking and analysed statistically, using peak heat release rate (HRR) and its location as reference data. The identification of the peak HRR crank angle was within a single degree accuracy as soon as the vibration amplitude was above the 100 m/s2 threshold. This encompassed 98.5% of the analysed combustion cycles. The peak HRR prediction accuracy had a maximum error below 21% and was suitable to monitor reaction rates.

Keywords: combustion engine, low-temperature combuston, Vibration, heat release rate, combustion control