MODELING AIR CHARGE IN VARIABLE VALVE TIMING ENGINES | ||||
| ERJ. Engineering Research Journal | ||||
| Article 7, Volume 30, Issue 2, April 2007, Page 177-187 PDF (702.78 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/erjm.2007.70052 | ||||
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| Author | ||||
| Safwat A. Wilson | ||||
| Mechanical Power Engineering Department, Faculty of Engineering, MinouJya University, Shebin E-Kom, Egypt | ||||
| Abstract | ||||
| Variable valve timing is a modern technique that aims to acquire the optimum air capacity at different operating conditions for internal combustion engines. The present work proposed a mathematical model to simulate the thermodynamic processes for motored engine including the air charge flowing through the intake manifold equipped with throttling valve. The pressure waves propagating through the intake manifold is considered. An experimental test rig consists of an engine equipped with measuring devices to record the engine speed, instantaneous cylinder and intake manifold pressure. Volumetric efficiency is estimated based on the experimental data at different engine throttling valve positions. The recorded data were compared with computational output in order to validate the proposed model. The model is used to address the effects of intake valve timing as well as throttling valve position at different engine speeds on the volumetric efficiency and equivalent compression ratio. The results show the importance of delaying the inlet valve closing angle with increasing engine speed to insure the best charge. The results show also remarkable effect of valve timing on the cylinder pressure. When delaying inlet valve closing angle, the effective compression ratio tends to decrease. | ||||
| Keywords | ||||
| Variable valve timing; intake manifold; air charge; pressure waves; volumetric efficiency | ||||
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