Abstract
Homogeneous Charge Compression Ignition (HCCI) combustion has demonstrated extremely low Nox emissions and high fuel efficiency. However, the combustion phasing must be controlled by different means than on Diesel or Spark-Ignited (SI) engines. A method for simultaneously controlling the HCCI combustion phasing and torque output was developed at the Southwest Research Institute, and applied to a six-cylinder engine. Dual-fuel HCCI combustion was used for operation up to 35% of the peak torque, and SI combustion was used for the rest of the operating range. This paper describes dual-fuel HCCI combustion, and the benefits obtained through its application.