An Enabling Study of Diesel Low Temperature Combustion via Adaptive Control

Low temperature combustion (LTC), though effective to reduce soot and oxides of nitrogen (NOx) simultaneously from diesel engines, operates in narrowly close to unstable regions. Adaptive control strategies are developed to expand the stable operations and to improve the fuel efficiency that was commonly compromised by LTC. Engine cycle simulations were performed to better design the combustion control models. The research platform consists of an advanced common-rail diesel engine modified for the intensified single cylinder research and a set of embedded real-time (RT) controllers, field programmable gate array (FPGA) devices, and a synchronized personal computer (PC) control and measurement system. Up to 12 fuel injection pulses per cylinder per cycle have been applied to modulate the homogeneity history of the cylinder charge in hybrid combustion modes in order to improve the phasing and completeness of combustion under independently controlled exhaust gas recirculation, intake boost, and exhaust backpressure.