Now, How About That !
»»»»»»»»»»»»»'GM's HCCI Engine'
»»»»»»»»»»»»» 'NewellClassic.com' 'Nears Reality'
»»»»»»»»»»»»» 'NewellClassic.com' ««««««~»»»»»» 'NewellClassic.com' «««««««««««««
« ~ » GM officials weren't talking about when the engine would actually make it into production vehicles.
But last week they let select journalists drive a Saturn Aura and an Opel Vectra, each outfitted with a
homogenous charge compression ignition engine.
« ~ » The technology has been kicking around for some 30 years and automakers have been developing
their own versions of it.
« ~ » It promises to deliver the efficiency (fuel economy) of a diesel engine with the emissions of a
typical gasoline engine. It accomplishes this magic because fuel is homogeneously premixed with air,
but it uses a high proportion of air to fuel. When the piston reaches its highest point, this lean fuel/air
mixture spontaneously ignites from compression heating, as in a diesel engine.
« ~ » HCCI engines burn cooler than spark-ignited and diesel engines. Lower temperature combustion
considerably reduces the emissions of nitrogen oxide and particulate matter.
« ~ » Several challenges have kept the technology from becoming commercially viable. Because the HCCI
engine does not have a combustion trigger such as a spark plug, the engine has been limited in the
speeds and loads it can it can manage. Yet GM's invited journalists report that they were able to get two
drivable concept vehicles, a 2007 Saturn Aura and Opel Vectra up to highways speeds easily enough.
------------------
May God Bless
KC
_______________
Source: Autoweek
|