Effects of the variable valve lift difference on in-cylinder gas flow in a four-valve gasoline engine
| Autor: | Miao Chi, Chunshu Li, Bao Jingyang, Ruilin Liu, Zhang Shiqiang |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Phase difference
Materials science 020209 energy Mechanical Engineering Flow (psychology) Aerospace Engineering 02 engineering and technology Mechanics Cylinder (engine) law.invention Variable (computer science) 020303 mechanical engineering & transports 0203 mechanical engineering law Flame propagation Valve lift 0202 electrical engineering electronic engineering information engineering Petrol engine |
| Zdroj: | Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. 233:1806-1817 |
| ISSN: | 2041-2991 0954-4070 |
| DOI: | 10.1177/0954407018789321 |
| Popis: | The in-cylinder gas flow is an important factor that affects the engine performance. The appropriate swirl can reduce cycle-to-cycle variations, increase flame propagation speed, and improve the combustion efficiency. Many technologies can induce significant swirl, but lead to intake flow loss. In this research work, the variable valve lift difference adjustment mechanism is developed to obtain and adjust in-cylinder swirl without weakening flow capacity in a four-valve gasoline engine. The in-cylinder swirl and tumble characteristics generated by the variable valve lift difference adjustment mechanism are studied by means of experiment and simulation. The results of the experiment and simulation show the intensity of tumble and swirl under the larger lift valve is increased with the increase in the phase difference between two intake cams at same camshaft angle, and a large-scale swirl is formed in the cylinder when the camshaft angles change from 40° to 80°, and another large scale swirl is formed during the camshaft angles change from 100° to 140°, but the rotating direction of the secondary swirl is inverse to that of first swirl. The scale and shape of the in-cylinder tumble and swirl are not changed significantly with the increase in the phase difference between two intake cams when the camshaft angles change from 80° to 100°. A brief discussion on the research results that improve the performance of actual gasoline engine is given. |
| Databáze: | OpenAIRE |
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