This surely has to be a ground breaking development. GM demonstrated the homogeneous charge compression ignition or HCCI, for the first time in two driveable concept vehicles, a 2007 Saturn Aura and an Opel Vectra. When combined with direct injection, electric cam phasing, variable valve lift and cylinder pressure sensing, HCCI can provide up to 15 percent fuel savings, while meeting with the emissions norms of the future.
“I remember debating this combustion capability when I was in college,” said Tom Stephens, group vice president, GM Powertrain and Quality. “It was just a dream then. Today, using math-based predictive analysis and other tools, we are beginning to see how we can make this technology real. By combining HCCI with other advanced gasoline engine and control technologies we can deliver a good fuel savings value for consumers”.
In an integrated engine concept, HCCI along with other enabling advanced technologies approaches the engine efficiency benefit of a diesel, but without the need for expensive lean NOx after-treatment systems. This efficiency is owing to the fuel burning at lower temperatures and reducing the heat energy lost during the combustion process. Also, less carbon dioxide is released because the vehicle”s operation in HCCI mode is more efficient.
The HCCI-powered concept vehicles drive like conventional gasoline vehicles but offer up to 15 percent improved fuel efficiency compared to a fuel injected engine.
“I am pleased with our engineering team”s progress,” said Stephens. “It is another initiative in GM”s advanced propulsion technology strategy to lessen our dependence on oil. HCCI, direct-injection, variable valve timing and lift, and Active Fuel Management all help improve the fuel economy and performance of our internal combustion engines. I am confident that HCCI will one day have a place within our portfolio of future fuel saving technologies.”
Highlights of HCCI technology include:
* Diesel-like engine efficiency with substantially reduced after-treatment cost
* Builds off proven gasoline direct injection and variable valve actuation technologies
* Adaptable to conventional gasoline engine architectures
* Requires only conventional automotive exhaust after-treatment
* Compatible with all commercially available gasoline and E85 ethanol fuels.