GM applying new intake valve lift control technology in 2.5L Ecotec for 2014 Impala; up to 1 mpg fuel economy boost
18 September 2012
|IVLC enables variable intake valve lift, duration and timing over a range of operation. Click to enlarge.|
GM is applying a new advanced valvetrain technology on the Ecotec 2.5L four-cylinder engine used in the 2014 Impala, due next year. Chevrolet’s redesigned flagship sedan will use new Intake Valve Lift Control (IVLC) technology that enables variable intake valve lift, duration and timing over a wide range of engine operation.
When the technology operates in low-lift mode, the engine pumps only the air it needs to meet the driver’s demand. The system switches to high-lift mode at higher speeds or under heavy loads, providing the full output capability of the engine. GM estimates the fuel savings at up to one mile per gallon, according to Mike Anderson, GM global chief engineer for Ecotec engines.
The engine achieves variable valve lift using a new rocker arm that switches between low and high lift intake cam profiles. The mechanism is actuated by an oil control valve through a dual-feed stationary hydraulic lash adjuster. It is the first of its kind for low-friction roller-type finger-follower valvetrains in gasoline engines, GM says. The engine’s computer continuously selects the optimal lift profile based on conditions such as engine speed and load.
Impala’s three powertrains all feature fuel-saving direct injection and lightweight components.
Impala’s Ecotec 2.4L engine works with the eAssist system to provide electrical assist in certain conditions to help save fuel. It is GM-estimated at 182 horsepower (134 kW) and 35 mpg (6.7 l/100 km) on the highway.
The Ecotec 2.5L is one of a new family of four-cylinder engines developed with increased efficiency and greater refinement. Output is estimated at 195 horsepower (145 kW).
Output for the 3.6L V-6 is estimated at 303 horsepower (226 kW).
All of Impala’s engines are matched with six-speed automatic transmissions. All models also feature an electric variable-assist steering system that helps save fuel by drawing energy only when the steering wheel is turned.
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