Efficacy Study of Polynomial Based Parametric Mapping in an RCCI Engine for Possible Control Applications 2021-01-0494

The present study depicts cubic polynomial function based parametric mapping of reactivity controlled compression ignition (RCCI) engine, across load sweep and gasoline energy share (GES). Based on the pilot experimental findings, the diesel (main) injection timing is determined followed by a set of experiments across the engine load sweep and GES, not exceeding 50%. Based on cycle to cycle variation of peak pressure, 50% burn crank angle (CA50) and indicated mean effective pressure (IMEP), engine stability values are computed. A set of RCCI engine parameters such as peak pressure, ringing intensity (RI), IMEP, CA50 etc. are normalized. The coefficients of polynomial are generated through surface fit to map all these parameters with normalized load and GES. Good conformity was observed between the predicted and modelled data. Subsequently, an operation window is proposed based on stability, combustion efficiency and thermal efficiency considerations. The proposed polynomials within the prescribed limits can be very much useful for designing look up tables, operation maps etc. and can also be valuable towards low cost RCCI engine development without exhaust gas recirculation (EGR).