04-04-2017, 03:38 PM
Literature review on cylinder deactivation
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cylinder deactivation literature review
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Literature review on cylinder deactivation
11-04-2017, 12:22 PM
In typical light loads that drive with large displacement engines (eg, road cruiser), only 30 percent of the potential power of an engine is used. Under these circumstances, the throttle valve is slightly open and the engine has to work hard to draw air through it. The result is an inefficient condition known as pumping loss. In this situation, there is a partial vacuum between the throttle valve and the combustion chamber, and part of the power that the engine makes is used not to propel the vehicle forward but to overcome the drag of the pistons and the crank Of the struggle to draw air Through the small opening and the resistance to vacuum that accompanies it in the butterfly valve. When a piston cycle is completed, up to half of the cylinder's potential volume has not received a full load of air.
The most consistent way to deactivate the cylinder is to not only cut the injection and ignition for the respective cylinders, but also stop all moving parts (including the pistons). This, in turn, utilizes all available thermodynamic potential and greatly reduces the friction that occurs within the engine. Needless to say, compromises should be made when it comes to the power on and dynamic balance sequence. What is much more significant, however, is the payout required to separate the engine in one area that continues to run while the other area is turned on and off as needed. Even the coupling mechanisms in the crankshaft and the camshaft can not be justified by a cost-benefit analysis, so the implementation of the system seems daunting today. Almost all currently used cylinder deactivation systems interrupt the injection and ignition as well as the valve actuation sequences for the cylinders to be deactivated . Current applications range from 4 to 12 cylinder engines. Analysis by Schaeffler, however, reveals that temporarily deactivating one of the cylinders in a three-cylinder engine can also further reduce fuel consumption. To ensure that the engine continues to run smoothly, only certain cylinders are deactivated according to the ignition sequence.
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