Topic
Spark-ignition engine
About: Spark-ignition engine is a research topic. Over the lifetime, 4352 publications have been published within this topic receiving 66550 citations.
Papers published on a yearly basis
Papers
More filters
••
TL;DR: In this article, the relationship between the timing for the onset of autoignition and the amount of mixture fraction burned by auto-ignition was investigated using a combination of high-speed laser shadowgraphy and thermodynamic calculations.
Abstract: In this study the relationship between the timing for the onset of autoignition and the amount of mixture fraction burned by autoignition and the resulting knock intensity is investigated using a combination of high-speed laser shadowgraphy and thermodynamic calculations. The experimental procedure is applied to examine the effect of a squish combustion chamber on suppressing knock. The results indicate that, when autoignition occurs in the squish area, an amount of mixture burned by autoignition is small, resulting in lower knock intensity
39 citations
••
14 Apr 2015TL;DR: In this paper, both EIVC and LIVC strategies have been examined aiming to achieve possible improvements for knock mitigation for turbocharged downsized spark ignition engine, and after some preliminary investigations confirmed that the latter was more effective than the former for this goal.
Abstract: The application of Miller cycle through Late Intake Valve Closure (LIVC) or Early Intake Valve Closure (EIVC) for knock mitigation at high load on a turbocharged downsized spark ignition engine was experimentally investigated. By reducing the effective compression ratio due to a shorter compression stroke and hence achieving lower charge temperatures inside the cylinder, significant mitigation of knock tendency could be obtained. As a consequence, the spark advance retard could be substantially decreased and the enrichment of the mixture could significantly be reduced, thus obtaining impressive efficiency improvements. In this research, both EIVC and LIVC strategies have been examined aiming to achieve possible improvements for knock mitigation and after some preliminary investigations confirmed LIVC being more effective than EIVC for this goal, the latter was discarded and the research activities were focused on LIVC only. Significant reductions in fuel consumption for high load engine operating points were achieved, especially at moderately high engine speeds, above 2500 RPM, where the turbocharger group was capable to compensate for the reduction of volumetric efficiency caused by the LIVC by means of an increased boost pressure. However, at lower engine speeds, despite these operating conditions being generally the most critical for knock occurrence, only minor positive effects were observed, since the lack of an adequate boost pressure did not allow further delays of the IVC, thus preventing the full exploitation of the Miller cycle. The highest gains were registered at 3000 RPM, at 18 bar and 20 bar BMEP, where the engine indicated fuel conversion efficiency was improved by about 11 and 20 percent, respectively. It is worth mentioning that, thanks to the Miller cycle exploitation, the engine could be operated under stoichiometric conditions in this region of its operating map, while normally adopted IVC timings typically require significant mixture enrichments.
39 citations
••
TL;DR: In this article, a CFD analysis is carried out to analyze in-cylinder air flows and air-fuel interaction created by different piston shapes viz., flat, flat-center-bowl, inclined and inclined-with-center bowl pistons in a four-stroke engine at an engine speed of 1500 rev/min.
39 citations
••
38 citations
••
01 Jun 1998
TL;DR: In this article, the completeness of combustion on a cycle-by-cycle basis has been investigated, where the normalized pressure rise due to combustion is introduced by the combustion par...
Abstract: This paper investigates a technique of calculating the completeness of combustion on a cycle- by-cycle basis. The technique introduces the normalized pressure rise due to the combustion par...
38 citations