Investigation of Asynchronous Valve Timings on a SI Engine for Turbulent and Performance Improving

Project objective

Investigation of feasibility of asynchronous valve timing approach for turbulent improving and its influences on engine combustion and performances at full load and high speed condition.

Project description

The spray angle, penetration, injection velocity were examined through flow visualization and PIV; SMD were measured by a laser diffraction system (Spraytec, Malvern Instruments) and compared to simulation results.

Analyzing of the in-cylinder global flow parameters (swirl, tumble ratios, TKE) under asynchronous valve timings. There are three abnormal cases: Advanced 10, Retard 10, and Retard 20 at 6000 rpm and wide open throttle (WOT).

Swirl and cross tumble ratios dramatic increased with asymmetric valve events; however, normal tumble slightly decreased. IMEP increased 9.37% in Advance 10 case.


D.K. Nguyen, M.H. Wu, Numerical Study on the Effects of Asynchronous Intake Valves Timings on Flow Charac-teristics in a SI Engine Combustion Chamber, The 25th Nat. Conf. Combust. & Energy, Kaohsiung, Taiwan, 2015.

D.K. Nguyen, C.W. Chen, C.Y. Wu, M.H. Wu, Numerical Study of Fuel Spray and Mixture Formation in a Spark Ignition Engine with Asynchronous Intake Valve Timings, The 13th ICLASS, Tainan, Taiwan, 2015 (submitting).