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By turning a portion of gasoline into hydrogen, then mixing the hydrogen back with gasoline in a combustion chamber, higher compression ratios can be used for better performance without the NOx production that is typical of lean-burn systems. That's the promise of the ArvinMeritor Plasma Fuel Reformer.
"Plasmatron" is a name that smacks of the sort of advancement in technology that the unit that ArvinMeritor (Troy, MI; www.arvinmeritor.com) is working to commercialize really is. Although that name was used by the researchers at the MIT Plasma Science and Fusion Center, from which the auto supplier has licensed the technology, they're calling it the "Plasma Fuel Reformer," a more descriptive, if mundane, moniker. This system, explains Pedro Ferro, vice president and general manager, ArvinMeritor Commercial Vehicle Emissions, "produces hydrogen onboard and on demand from the vehicle's fuel." That fuel can be either diesel or gasoline. With the system there's no need for a hydrogen infrastructure, as the system does the job.
As "Plasmatron" implies, a plasma cloud of ionized gas is generated, through which atomized fuel is passed. That induces a partial oxidation reaction, which results in H and CO. The hydrogen can then be mixed in the vehicle combustion chamber with gasoline. As a result, says Garrick Hu, vp of Advanced Engineering, ArvinMeritor Commercial Vehicle Systems, "You're extracting more of the energy from the fuel than you do in a normal gasoline engine." He explains, "It gives you flame stability, so you have the ability to operate in a lean condition. Your lean limit can move. Your knock limit can move. You can go to higher compression ratios. Higher compression ratios give you more power." He adds, "Typically that yields a higher NOx production—but not in this case."
This results in a 20% to 25% improvement in fuel efficiency. What's more, because of the efficiency of the burn, there is less aftertreatment of the exhaust involved, which can reduce the cost of catalysts.
When could we see a Plasmatron on an engine? John M. Grace, vp, Engineering and Technology, ArvinMeritor, suggests that it could be "within two to five years."