Abstract
One of the main challenges of HCCI engine research is developing a system to control the combustion phasing to achieve a stable operation. Though some HCCI combustion control systems have been suggested, they are heavy in weight and complex in mechanism. In this study, a simple combustion control system and an algorithm for a lightweight small-sized handy electrical generator HCCI engine fuelled with DME were developed and evaluated experimentally. In this system, the ratio of stoichiometric DME/air pre-mixture, Hot EGR gas and Cold EGR gas were adjusted by throttles. The experimental results showed that combustion phasing can be controlled through adjusting the mass-averaged in-cylinder gas temperature at intake valve closure timing by changing the ratio of Hot EGR gas and Cold EGR gas. Moreover, IMEP was PI (Proportional and Integral) feedback controlled by fuel flow rate, while the combustion phasing and equivalence ratio were PI feedback controlled by throttles. As a result, it is possible for these parameters to follow their set values.
