| Autor: |
Hisao Nakamura, Seiichi Shiga, Takao Karasawa, Shizuo Yagi, Munehiro Morita, Takashi Matsumoto |
| Rok vydání: |
1996 |
| Předmět: |
|
| Zdroj: |
SAE Technical Paper Series. |
| ISSN: |
0148-7191 |
| DOI: |
10.4271/960585 |
| Popis: |
In this paper we present the first stage of a study on the effect of early-closing of intake-valve on the engine performance in a spark-ignition engine. A four-valve single-cylinder engine was used with several values of expansion ratio and a half early-closing intake cam. The half early closing leads to almost a half of the volumetric efficiency and the BMEP for all cases of the expansion ratio. It can realize an improvement of about 7% in thermal efficiency under WOT, and about 4% under partial load of BMEP=0.2 MPa. These beneficial results are considered to be mainly caused by the effect of the more-expansion. The ratio of expansion to compression ratios was estimated to be around. 1.4 on the basis of motoring pressure analyses. Under the early-closing condition, an increase in the residual gas fraction was suggested and verified by a heat release analysis using a two-zone combustion model. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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