Proof-of-concept trials for Federal Mogul’s Advanced Corona Ignition System (ACIS) signal the likelihood of the first production applications in the 2016-2018 timeframe.
“We are in technical discussions with more than 20 companies in the automotive and industrial segments. And of those companies, we are actively testing with nine in the R&D phase and a few of the projects are moving to the advanced engineering stage,” Kristapher Mixell, Federal Mogul’s Director of ACIS, told SAE Magazines.
Unlike a conventional spark plug that creates a small arc across the electrode gap, ACIS produces multiple streams of ions from a four-pointed-star tip to excite the air/fuel mixture into combusting.
Increased use of EGR to reduce engine-out emissions is a major driver for new high-intensity ignition solutions such as ACIS. “As fuel mixtures become more dilute and lean, these mixtures become more difficult to ignite and are slower burning. Only so much can be accomplished with ignition that begins in one place,” Mixell said, referencing multi-strike, spark gap, combustion chamber turbulence, and other ignition strategies.
“In a nutshell, we take 12 V DC from the vehicle’s electrical system and step it up to an intermediate DC voltage—meaning less than 150 V DC," he explained. "The intermediate voltage is then fed into a high-frequency amplifier, which excites at resonance the igniter assembly and in turn generates an electric field up to about 70 kV at about 1 MHz."
ACIS’s average power consumption can be significantly less than a vehicle’s premium audio system at the same operating conditions, Mixell noted.
The system is designed to run on any number of cylinders and can be calibrated to match ignition energy with combustion demands. The hardware, however, is currently configured to support a maximum of eight cylinders. Regarding packaging on production applications, Federal Mogul engineers anticipate the coil with its integrated electronics to be about the same size as a contemporary ignition coil. There would also be a small, separate power supply box with control electronics.
“We’re making sure that the value proposition is right, so we’re not using exotic materials for any of the components,” said Mixell. He noted that many of the system’s components are being made at Federal Mogul facilities in the U.S. and Europe.
In trial applications, replacing conventional spark plugs with the Corona system has not necessitated significant re-designs. “The customers who are testing our technology haven’t made major modifications to cylinder heads, engine architecture, or electrical systems," Mixell said. "I wouldn’t call it quite as simple as plug and play, but it’s about as close as you can get.”
Although many of the current ACIS projects are boosted, direct-injected gasoline engines, the system is compatible with ethanol and ethanol blends as well as methanol, compressed natural gas (CNG), and other alternative fuels. Mixell noted that “industrial customers are running natural gas with the technology and are principally focused on stationary applications.”
During internal tests conducted with a 1.6-L, four-cylinder turbocharged gasoline engine, the ACIS helped realize a 10% fuel consumption improvement. Mixell said the ACIS enables engine calibrators to have more control over the ignition event, ignition power level, and the amount of energy that goes into the ignition event. The system also fosters the implementation of advanced combustion strategies aimed at lower engine-out emissions.
Federal Mogul technical specialists faced some tough engineering challenges. “The frequency and power ranges encountered on ACIS are unusual and have presented challenges during development. Solving these challenges was quite difficult,” Mixell said, declining to provide specific details on the solutions.