General Motors has updated its 2.5L Ecotec four-cylinder engine for its new 2014 Chevrolet Impala to improve fuel economy and reduce engine noise. The automaker said it is using Intake Valve Lift Control technology to boost mpg.
According to the company’s Mike Anderson, General Motors’ global chief engineer for Ecotec engines, the new EPA-estimated fuel economy for the 2014 Impala with the 2.5L engine is 21 mpg city, 31 highway.
The new system in the engine allows its valves to open and close by variable amounts, and at different times, based on the vehicle’s power demand. When the engine operates in low-lift mode, it only pumps enough air to meet the vehicle’s power needs. It switches to high-lift mode at higher engine speeds or when the vehicle is under heavy load. The 2.5L engine is SAE-certified at 196 hp and 186 lb.-ft. of torque, according to GM.
Other changes to the engine helped reduce noise. GM said its engineers reduced engine noise intensity by 40% by targeting the engine’s specific noise frequency signature. GM’s engineers pushed the frequency of radiated noises above the 2,000 hertz range, which is easier on human ears, according to GM. They also added a sound-absorbing cover into the intake manifold, used quieter drive chains, relocated the balance shafts from the cylinder block to a cassette in the oil pan, and used active noise cancelling technology and a more “refined” engine sound as the engine revs up to its 7,000 rpm peak.
The 2014 Chevrolet Impala provides three engine choices, including a 3.6L V-6, the new Ecotec 2.5L four-cylinder, and the company’s Ecotec 2.4L with eAssist.