General Motors has not released many supplier names for its Chevrolet Volt extended-range electric vehicle program, slated for production in 2010. So Germany-based Buehler Motor GmbH is way ahead of the pack in confirming a production contract for a key application for the car—12-W and 50-W auxiliary coolant pumps used for cooling multiple subsystems in the advanced-propulsion vehicle.
According to Robert Riedford, President and General Manager of Buehler Motor Inc., the company’s U.S. group, the Volt contract presented a “tough engineering challenge” to the 150-year-old supplier of mechatronic technologies, including specialized electric motors and controls.
“The pumps have to run extremely quietly because this is an electric car,” Riedford explained, “and they have to be extremely robust.” Volt will use “multiple” 50-W pumps and at least one 12-W pump, he said. The 50-W unit features its own integrated electronics.
Another technical challenge was developing a novel method of sensing the pump’s impeller speed, Riedford said. The pumps’ overall mechatronic design features brushless dc motors, similar to the type used by Buehler in its four-wheel-drive transfer case actuator systems produced for GM, Magna, and others since the 1990s.
Speaking at Buehler’s booth at the recent Convergence 2008 conference, Riedford explained that he cannot divulge much technical detail at this stage of the Volt’s development. Buehler Motor and GM have been working together in a technology partnership since mid-2007 on the coolant pump systems. Buehler engineers are stationed at GM’s Volt engineering center in Warren, MI.