Abstract

HCCI engines are likely to become one of the future alternatives to SI engines due to their ability to deliver high efficiency and low NOx emissions. There are, however, problems with the control of the ignition and heat release rate over the entire load and the speed range, which limits the practical application of this technology.
In order to investigate the combustion parameters of both SI and HCCI gasoline engines, a widely used and powerful diagnostic tool is the analysis of the in-cylinder pressure time history as derived from in-cylinder pressure transducers. Such information has particular application in HCCI engines for control of TRG levels, valve timing, misfire and knock detection.
Unfortunately, although the use of in-cylinder pressure transducers for that purpose has been an invaluable research tool, it is not without problems. In the case of HCCI combustion, the violent rates of heat release make the signal derived from pressure transducers more prone to thermal shock. In addition, in HCCI research, it is often necessary to establish the TRG amount as accurately as possible. However, TRG presence also complicates pegging techniques. Since the pressure transducer signal can be compromised
by these calibration issues, it is prudent to try to address these issues when dealing with pressure signals derived during HCCI operation. The present article presents an algorithm aiming to account for these calibration
issues surrounding the use of pressure transducers in HCCI research. Results for the TRG amount and initial mixture composition and temperature on a cycle-to-cycle basis are also derived.