Just about every automaker is looking to do everything they can to improve fuel economy and reduce emissions. One of the ways this is commonly happening in cars today is by ditching larger displacement engines and going with smaller turbocharged engines. This introduces more efficiency and power to a smaller engine, but also brings with it some other issues.
One of the biggest complaints with a turbo engine is called lag. From the time the driver steps on the throttle until the turbo is spinning fast enough to help the engine along takes a bit of time meaning the car doesn’t react as soon as you step on the pedal. GM has a new patent application that shows a new two-stage turbo system that would specifically be aimed at reducing or eliminating lag in turbo cars.
The two-stage system has a low and high-pressure turbine in a series. The design allows the isolation of the low or high-end side of the turbo. The goal is to allow the engine computer to optimize the car for performance in both the low-end range and the high-end range making the car perform better all around.
via GM Authority