Design and Experimental Investigation of a Novel Skip Cycle Mechanism

Abstract

The main problem in near future is to increase the eciency of internal combustion engines, which is the most important cause of air pollution in cities and the reduction of exhaust emissions from these engines. When operating conditions are examined in passenger cars, which are the main users of internal combustion engines, it has been seen that high fuel consumption occurs in the partial load area. A new working method for internal combustion engines, skip cycle strategy, which were revealed by Kutlar in 1999 has similarities with the cylinder deactivation systems, but it also has advantages especially in the application to single cylinder engines. The skip cycle strategy is a method of reducing the power taken by the engine, in other words, reducing the pumping losses in the partial load area. In this work, the control process has been provided according to cycle conditions and depending on skip cycle system needs, besides the mechanical valve control. The created mechanism consists of two groups: lock system and control system. In this study, the kinematic analysis of the engine has been carried out and the loads acting on the system have been determined. Finally, mechanism has been manufactured and experiments have been carried out at di erent speeds according to the NS (Normal cycle-Skip cycle) method, which is one of the several skip cycle strategies.