In the heavy-duty engine area, CRF researchers are focused on providing fundamental understanding of various Low-Temperature Combustion (LTC) strategies appropriate for diesel fuel, HCCI/SCCI fundamentals generic to all engine sizes, advanced diesel combustion strategies (e.g., use of high levels of Exhaust-Gas-Recirculation (EGR), variable fuel injection timing, multiple injection pulses per cycle, and/or high-pressure injection), and the fundamentals of fuel sprays for these applications.