Variable displacement

The cylinder shut-off ( CCO ) is a late 1970s developed system to reduce fuel consumption of internal combustion engines.

In situations of low power demand, the fuel supply is cut off or no fuel is injected. The valves of the deactivated cylinders are kept closed to prevent gas exchange losses. This measure was in the late 1990s to reduce fuel consumption by up to 15%. Depending on the system can be either an entire bank of cylinders (V- engines) or single cylinder (single cylinder deactivation) are switched off. The system is used, mainly because of a certain minimum - quiet operation, mainly for engines with a minimum of eight cylinders.

In hybrid drives the entire combustion engine is switched off and driven in electric mode; here one speaks of a " motor switch-off ".

Daimler had the ZAS offered as an option in the 5- liter V8 version of S -Class and CL (M - 113 engine ) to about 2005. Previously, you had the technology already used in the comparatively short-lived M - 137 V12 engine. Meanwhile, the cylinder deactivation took place at the subsidiary Mercedes- AMG in the Mercedes SLK 55 AMG new feeder.

Other manufacturers using a cylinder shut-off (" up to 20 percent depending on driving style and vehicle use " savings) since 2005, the Hemi V8 engines ( 5.7 liter) engine of Chrysler, Jeep and Dodge.

At Honda, the technique is sometimes even used in four-cylinder engines such as the Honda Civic Hybrid. GM uses them under the name " Active Fuel Management" in various V8 and some V6 engines. One of the most suitably equipped models is the 2010 Chevrolet Camaro SS introduced

The Mercedes- AMG sister wants to reduce consumption of its models by 2012 by 30 per cent; for they bring 2011 model SLK 55 AMG a new gasoline direct-injection V8 engine, which uses an enhanced version of cylinder deactivation and to temporarily uses only four cylinders.

When are switched off at part load cylinder, also referred to as " dynamic downsizing".