General Motors is testing a new combustion process that may raise fuel mileage in gasoline
engines by up to 15 percent.
The process, called homogeneous charge compression ignition,
provides fuel efficiency close to that of a diesel, without requiring expensive pollution
controls needed by diesels to meet current regulations.
The process, which is undergoing
tests in a Saturn Aura and an Opel Vectra, ignites the air-fuel mix by compressing it. This
produces a low-temperature, flameless energy release simultaneously throughout the
combustion chamber, allowing the engine to require less fuel to produce equivalent power as
a conventional engine.
GM said it still needs more work on controlling combustion and gave
no estimate of when the technology will be offered to the public.