Effects of the Stroke/Bore Ratio on the Performance Parameters of a Dual-Spark-Ignition (DSI) Engine

Abstract

In this study, the effects of the stroke/bore (S/B) ratio on the performance parameters of an engine having dual-spark ignition (DSI) were investigated theoretically by using a quasi-dimensional thermodynamic cycle model. A range of S/B ratios for various spark-plug locations were examined in the scope of the study. The engine performance parameters, i.e., engine power, indicated mean effective pressure, specific fuel consumption, and thermal efficiency, were computed for various conditions. The obtained results for DSI operation have been compared to those of a single-spark-ignition (SSI) condition. Such comparisons showed that increases in the S/B ratio cause improvements in engine performance parameters. The dual-plug operation also improves the overall engine performance at different percentages for the selected S/B ratios.

Analysis of the effect of bore/stroke ratio and scavenge port angles on the scavenging process in a two-stroke boosted uniflow scavenged direct injection gasoline engine

“…As a result, a small B/S ratio design usually shows higher combustion efficiency and thermal efficiency. 8,9,11,[16][17][18][19][20] However, as the engine speed increases, the advantage of long stroke would be gradually lost as the friction loss significantly increases. 8 It is also reported that the reduced convection heat losses at part load could compensate the unfavorable surface/volume ratio for a ''square'' design with B/S ratio of 1, resulting in fuel consumption benefits by improving the reciprocating and rotating components stress and friction at high speed.…”

“…21 In addition to the fuel conversion efficiency, the variation in the B/S ratio also shows impacts on exhaust emissions. As the B/S ratio increases, the increased crevice volume could lead to increased carbon monoxide (CO) and hydrocarbon (HC) emissions, 17,18 but lower nitrogen oxide (NOx) emissions. 17 Compared to the four-stroke engines, the performance of two-stroke engines is more affected by the B/S ratio because of its direct impact on the scavenging process of the two-stroke cycle operation.…”

“…As the B/S ratio increases, the increased crevice volume could lead to increased carbon monoxide (CO) and hydrocarbon (HC) emissions, 17,18 but lower nitrogen oxide (NOx) emissions. 17 Compared to the four-stroke engines, the performance of two-stroke engines is more affected by the B/S ratio because of its direct impact on the scavenging process of the two-stroke cycle operation. Yang et al performed a numerical study on the effect of B/S ratio on the scavenging process in a poppet-valve two-stroke engine.…”

“…As the B/S ratio increases, the increased crevice volume could lead to increased carbon monoxide (CO) and hydrocarbon (HC) emissions, 17,18 but lower nitrogen oxide (NOx) emissions. 17…”

Farkli Buji̇ Sayilari Ve Konumularina Sahi̇p Buji̇ Ateşlemeli̇ Bi̇r Motorda Ateşleme Avansinin Motor Performans Parametreleri̇ Üzeri̇ndeki̇ Etki̇si̇

“…Bu çalışmanın odağında BA motorlarda çift buji ile ateşleme yönteminin kullanımı bulunmaktadır. Çift buji ile ateşleme yönteminde; silindir kafasında eksenel simetrik [13,14] veya diyagonal [15] olarak yerleştirilmiş iki adet buji yer almaktadır. Bujilerde ateşleme işlemi çalışma koşullarına bağlı olarak eş zamanlı veya sıralı olarak yapılabilmektedir [16].…”