Modelling and Validation of Automotive Engine Fuelled with Palm Oil Biodiesel

Abstract

This paper presents the Black-box modelling of automotive diesel engine fuelled with palm oil biodiesel (Palm Oil Methyl Ester). The aim of the work described in this paper is to obtain linear dynamic model of the palm oil biodiesel from test data. Assuming a discrete time form for the system model, an Autoregressive Moving Average with eXogenous input (ARMAX) model structures was selected in this work. A Pseudo-Random Binary Sequence (PRBS) with maximum lengths sequence of 31 has been used as the test input signal to the engine at the speed range around 2100 rpm. The input and output signals were interfaced to the plant via Matlab programming. Recursive estimation algorithm, Recursive Extended Least Squares (RELS), is used to estimate the model parameters. Finally, model validation was done by comparing the output predicted by the model against the measured output and also by error analysis. The mathematical model developed in this study present an analysis and simulation tools of engine dynamic system that forms the foundation for a systematic approach to the analysis, simulation and synthesis of the automotive palm oil biodiesel engine control systems. The model derived in this work is intended for the development of self-tuning engine speed controller in future work. Index Terms—Identification; Modeling; Biodiesel; Palm oil biodiesel