TRAVERSE CITY, MI – Superchargers are most associated with fire-breathing hot rods and muscle cars such as the Corvette ZR-1 and Cadillac CTS-V.
But they’re poised to play a major role in improving the fuel efficiency and emissions of small cars, diesels and even some hybrid-electric vehicles,President Ken Davis says.
“We are discovering you can supercharge small displacement engines without sacrificing engine performance,” Davis says at the Center for Automotive Research’s Management Briefing Seminars here.
“Supercharging has completed the transformation from a low-efficiency, high-horsepower add-on to a high-efficiency, low-fuel-consumption boosting technology.”
controls about 90% of the small global market for superchargers, but Davis is focused on the giant – and growing – market for forced-induction engines that turbochargers now dominate.
Thanks to relatively recent technology breakthroughs that improve efficiency and lower cost, Eaton’s supercharger revenue doubled from 2006 to 2009 and is expected to double again in the next three to five years, Davis tells Ward’s in an interview.
Much of this growth will come in small displacement gasoline and diesel engines where superchargers now rarely are found, he says.
A typical new application is a supercharger on a 1.2L gasoline engine on the ’12Micra in Europe. Eaton also is hoping to announce a contract to supply a supercharger for a European passenger-car diesel by the end of the year. Dozens more projects in gasoline and diesel engines currently are under development, Davis says.
“Superchargers offer engine designers the opportunity to downsize and down-speed engines,” he says. “Our OEM customers can slow down the engine speed and supercharge the powertrain without losing performance, and providing additional gains in fuel economy and weight reduction.”
The ability to down-speed comes from the fact that superchargers do not need time to spool up to provide boost pressure that allows the engine to make additional power and torque. Traditionally considered more expensive than turbochargers, new production supercharger applications reduce part-number proliferation, weight, installation costs, emissions and fuel consumption, Davis says.
The supercharger used on the superb Audi 3.0L V-6, a 2010 and 2011 Ward’s 10 Best Engines award winner, is a single module that easily can be bolted on the engine block on the assembly line. A comparable twin-turbo layout requires far more complex assembly, he says.
Superchargers also are demonstrating the ability to reduce oxides of nitrogen and transient smoke from diesel engine exhaust, a benefit that now is attracting lots of attention as diesel-emissions regulations grow ever tighter.
And while superchargers and HEVs may sound like an odd couple, Davis says auto makers are interested in supercharging, rather than turbocharging some hybrids, because of bearing wear and other concerns about turbos in these applications.
Eaton currently supplies superchargers for hybrid versions of theTouareg and Porsche Cayenne cross/utility vehicles. Supercharger technology was developed in the 1800s as an air pump for use in blast furnaces, Davis says. It then found its way into large vehicles and airplanes.
In the 1950s, supercharging began to catch on with professional drag racers as a way to increase speed. Then it made its way onto street rods and hot rods, and the high performance of the supercharger was truly born, Davis says.
The first devices were fairly rudimentary, 2-blade designs that required a lot of horsepower to make them work. Eaton began working with the technology in the 1950s to see if it could make it more efficient and affordable for truck and automotive customers.
“We eventually patented a 3-bladed design with a 60-degree twist for greater efficiency and created an advanced manufacturing process to reduce costs and improve durability and reliability,” Davis says.
In 1988, the first production version went into theThunderbird Super Coupe and became highly successful, ending up in nearly 50 production vehicles from the 1.0L engine in the Ford Fiesta in Brazil to the large-displacement V-6s and V-8s that still are in the market today.
Another major breakthrough came in 2007. “We added a fourth blade, or lobe, to the supercharger rotor, and we modified the twist from 60 degrees to 160 degrees,” Davis says.
This change improved the overall efficiency of the supercharger by more than 20%. “Today, this technology is really opening a lot of opportunities for us,” he says.