Volkswagen has released a statement confirming that the company will be utilising a cylinder shut-off system in its 1,4-litre TSI engine by early 2012. This will be the first time a manufacturer employs this type of efficiency technology on a mass-production, four cylinder direct injection engine. Volkswagen states: “cylinder shut-off reduces fuel consumption of the 1,4 TSI by 0.4 litres/100 km in the NEDC driving cycle.”
The fuel consumption advantage is realised by shutting off cylinders 2 and 3 during constant light speed and load conditions (1 400 r/min – 4 000 r/min, 25 N.m – 75 N.m) which reduces pumping losses. This ensures that the engine’s NVH characteristics remain smooth and unobtrusive to the driver. Mechanically, the shutoff is achieved by moving the cam lobes on the camshaft along a splined section on the camshaft in order to prevent the lobes from operating the valves on the disabled cylinders during the shut-off phase (see video).
The intelligent engine control system can identify the driver’s desired driving mode by monitoring the accelerator pedal input and decide to suppress the shut-off function in case the inputs are erratic or non-uniform – for example during sporty driving.
