WOODCLIFF LAKE, NJ - BMW's four-cylinder engine will return to its U.S. lineup of vehicles for the first time since 1999. The automaker said that U.S.-specific model and timing information will follow at a later date but that the engine will arrive in vehicles in 2011. The new 2.0L engine will combine twin-scroll turbocharging with high-pressure direct-injection and BMW's VALVETRONIC intake control and offer 240 hp and 260 lb.-ft. of torque.
The engine achieves its maximum output of 240 hp at 5,000 rpm, 1,500 rpm lower than in the normally aspirated inline-six. The peak torque of 260 lb.-ft., comes on stream at just 1,250 rpm. The four-cylinder engine features an all-aluminum crankcase, making it lighter and more compact than a six-cylinder engine of equivalent power. The turbocharger is a twin-scroll system. The exhaust streams leaving the two pairs of cylinders are kept completely separate as they flow through the exhaust manifold and the turbocharger, taking a spiral path to the turbine wheel. This configuration results in very low exhaust back pressure at low engine rpm, and allows the energy of the exhaust gas pulses to be optimally managed and translated into powerful rotation of the turbine blades, without a delay in throttle response.
