Combustion research heats up

As calls for lower CO₂ emissions grow louder, fuel system, valvetrain, electronic control, and analytical technologies are helping to unlock greater efficiencies inside the cylinder.

From behind his laptop screen in the Saturn Aura mule, General Motors Senior Staff Engineer Vijay Ramappan smiled confidently. The car and its special 2.2-L Ecotec engine were performing well, as expected, despite the snowstorm on this frigid January morning.

As the AEI reporter at the wheel covered a 12.5-mi (20-km) public-roads loop through Pontiac, MI, a small screen on the Aura's instrument panel displayed the engine speed/load map in real time. The map showed the car operating in fuel-saving homogeneous-charge compression ignition (HCCI) mode for 75% of the test drive, switching to conventional spark-ignition mode at high loads.