GM Files Patent for New 2-Stage Turbo System

General Motors Co. is developing a new two-stage turbocharger technology designed to minimize previous tradeoffs between low- and high-pressure operations for such systems.

Last month the carmaker applied for a U.S. patent for the design, reports GMI Inside News. The setup features a bypass valve in the high-pressure turbine inlet duct and a low-pressure turbine valve in the connecting channel.

A single actuator housed in the exhaust manifold is used to open and close both valves as needed to allow the turbochargers to work together across a broader operating range, according to the patent. GM says the system reduces mechanical complexity, enhances fluid dynamic performance and limits traditional turbo lag.

Current two-stage turbochargers allow both turbines to operate simultaneously at low and mid-range engine speeds. But only the low-pressure unit works at higher speeds.