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A Study of High Compression Ratio SI Engine Equipped with a Variable Piston Crank Mechanism for Knocking Mitigation
Technical Paper
2011-01-1874
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
To avoid knocking phenomena, a special crank mechanism for gasoline engine that allowed the piston to move rapidly near TDC (Top Dead Center) was developed and experimentally demonstrated in the previous study. As a result, knocking was successfully mitigated and indicated thermal efficiency was improved [1],[2],[3],[4]. However, performance of the proposed system was evaluated at only limited operating conditions.
In the present study, to investigate the effect of piston movement near TDC on combustion characteristics and indicated thermal efficiency and to clarify the knock mitigation mechanism of the proposed method, experimental studies were carried out using a single cylinder engine with a compression ratio of 13.7 at various engine speeds and loads. The special crank mechanism, which allows piston to move rapidly near TDC developed in the previous study, was applied to the test engine with some modification of tooling accuracy.
Experimental result showed that indicated thermal efficiency as improved at 1000 r/min from low to high load, and at 1600, 2000 r/min high load by Leaf-shape mechanism. Improvement of indicated thermal efficiency at 1000 r/min was due to the reduction of cooling loss and at 1600, 2000r/min high load due to the recovery of the degree of constant volume. Also it was found that high load operation with compression ratio of 13.7 without knocking was realized using the proposed piston movement mechanism. Auto-ignition occurred at high load conditions even though the proposed piston movement was applied, but auto-ignition was not followed by high frequent in-cylinder pressure oscillation shown in the case of knocking.
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Morikawa, K., Yoshimatsu, A., Moriyoshi, Y., Kuboyama, T. et al., "A Study of High Compression Ratio SI Engine Equipped with a Variable Piston Crank Mechanism for Knocking Mitigation," SAE Technical Paper 2011-01-1874, 2011, https://doi.org/10.4271/2011-01-1874.Also In
References
- Morikawa, K. Kaneko, M. Moriyoshi, Y. Sano, M. A Study on New Combustion Method of High Compression Ratio Spark Ignition Engine SAE Trans. Technical Paper No. 2005-01-0240 1 8 2005
- Moriyoshi, Y. Sano, M. Morikawa, K. Kaneko, M. Proposition of a New Gasoline Combustion System in High Compression Ratio Operation with High Thermal Efficiency - Realization by using Inconstant Speed Crank System Transaction of JSAE, 20064368 2006 79 84
- Morikawa, K. Kaneko, M. Oiwa, H. Moriyoshi, Y. High Compression Ratio High Efficiency Gasoline Engine with Variable Speed Piston-crank Mechanism Transactions of JSME, No.07-7012, B73-735 2007 11 4 10
- Morikawa, K. Moriyoshi, Y. The research and development of a high thermal efficiency gasoline combustion system in high compression ratio and low thermal loss NEDO accomplishment report 2008-3 1 34