Research Accelerated into Flameless Ignition

The reality of a highly efficient combustion technology that boosts fuel economy and does away with spark plugs may arrive just a bit sooner after an announcement Monday.
The announcement of $2.5 million U.S. in research dollars over three years will help Robert Bosch GmbH, General Motors Corp. and Stanford University develop homogenous charge compression ignition (HCCI) technology that could increase fuel economy by 20%.
HCCI also lowers pollution from diesel engines, said Gary Smyth, director of GM’s power train systems research laboratory, during a media briefing at the automaker’s technical centre in Detroit.
HCCI is able to achieve increased fuel efficiency in gasoline engines and decreased emissions from diesel engines because it uses a flameless ignition method instead of a sparkplug to create the explosion that moves an engine’s pistons.
With HCCI, the explosion is triggered by spontaneous combustion from heat created when the mixture of air and fuel is compressed by the piston, similar to the ignition process of a diesel engine.
The lower temperature combined with a higher mixture of air to fuel raises fuel economy and virtually eliminates nitrogen oxide emissions from diesel engines.
“It is simply a better way to combust,” said Dr. Rolf Leonhard, executive vice president, engineering gasoline systems division at Robert Bosch GmbH in a statement.
The technology has been around for about 25 years, with almost every automaker attempting to perfect it.
“This is the holy grail of internal combustion engines,” said Lindsay Brooke, an analyst with Farmington Hills-based forecasters CSM Worldwide Inc. “If all internal combustion engines were an HCCI type of engine, all costs related to production would be greatly reduced.”
While in theory HCCI provides benefits, considerable challenges stand in the way of commercialization.
“It’s difficult to control,” said Paul Najt, GM group manager of spark ignition engine systems. “We have to control precisely the temperature, pressure in the combustion chamber and we have to control that differently depending on the fuel that is used.”
Bosch’s role in the three-way research program is to develop sensors, actuators and other parts for engines using HCCI. Stanford University is working on the physics of this type of combustion and training in what GM’s Smyth described as “the next generation of engineers” to work with the technology.
While the public is clamouring for better fuel economy as fuel prices skyrocket, Smyth says commercial use of HCCI is at least a “few years away” while automakers and their partners look to overcome its obstacles.
If it is perfected, HCCI could be installed in hybrid electric vehicles making them even more fuel efficient, according to Najt.