Effect of a Cylinder Deactivation Actuator with Electro-Mechanical Switching System on Fuel Economy of an Automotive Engine

This paper introduces a two-step CDA mechanism equipped with an electro-mechanical switching system, which can be applied to OHC valve trains with end pivot rocker arms, and can operate two valves simultaneously with a single cam. The electro-mechanical switching system is driven by a dedicated solenoid, so the latching and unlatching processes are not affected by the temperature and pressure of the engine oil. Therefore, not only the dynamic stability can be secured at the time of mode switching but also the operation delay time can be kept short enough. To verify the effect of the CDA system on the fuel economy, a four-cylinder 2.0L gasoline engine with the intake port injection was selected and tested on an engine dynamometer. The effect of the present apparatus was evaluated by measuring the fuel economy of the engine in the two test modes: Federal Test Procedure-75 (FTP-75) and Worldwide Harmonized Light Vehicles Test Procedure (WLTP). The optimal operating conditions were established which minimize the engine vibration, friction loss and the adverse effects on fuel efficiency. According to the optimum operating conditions, the fuel efficiency improvements of 9.56% and 8.01% were obtained in FTP-75 and WLTP test modes respectively. Stable and quick response of the electro-mechanical switching system may attribute to the relatively big improvements in the fuel economy.