CAJ | 학술논문

在一台四缸柴油机改造的火花点火甲醇缸内直喷发动机上,高负荷时,在进气冲程将燃油喷入缸内,形成近化学计量比的混合气来实现均质燃烧.通过对典型工况的气缸压力的测量和分析,探讨了不同参数对甲醇发动机燃烧特性的影响.结果表明:甲醇缸内直喷发动机最大功率和最大扭矩比原机分别提高5.88%和20.90%,发动机最高热效率可达35.3%,远高于普通汽油机水平.甲醇缸内直喷发动机的滞燃期和急燃期随负荷的增加而变小.全负荷时,甲醇发动机的燃烧放热始点随转速的增大而推迟,滞燃期和急燃期随转速的增大而增加.发动机循环变动随工况的变化规律与滞燃期一致.
재일태사항시유궤개조적화화점화갑순항내직분발동궤상,고부하시,재진기충정장연유분입항내,형성근화학계량비적혼합기래실현균질연소.통과대전형공황적기항압력적측량화분석,탐토료불동삼수대갑순발동궤연소특성적영향.결과표명:갑순항내직분발동궤최대공솔화최대뉴구비원궤분별제고5.88%화20.90%,발동궤최고열효솔가체35.3%,원고우보통기유궤수평.갑순항내직분발동궤적체연기화급연기수부하적증가이변소.전부하시,갑순발동궤적연소방열시점수전속적증대이추지,체연기화급연기수전속적증대이증가.발동궤순배변동수공황적변화규률여체연기일치.
For a direct-injection spark-ignition (DISI) methanol engine retrofitted from a four-cylinder diesel engine, fuel is injected into the cylinder during the intake stroke to realize the homogeneous charge combustion for the high power output. The cylinder pressure of typical operating conditions was measured and analyzed. The effects of different parameters on methanol engine combustion characteristics were investigated. The results showed that the maximum power output and torque of the methanol engine are 5.88% and 20.90% higher than original diesel engine, respectively. The maximum brake thermal efficiency reaches 35.3% at a speed of 1500r/min, and a brake mean effective pressure of 0.85MPa, which is higher than the conventional gasoline engine. The ignition delay period and rapid combustion phase increase with decreasing load. The start of combustion is postponed with increasing speed at full load. The ignition delay period and rapid combustion phase increase with increasing speed under full load. The change of the cyclic variations has the approximate trend with that of the ignition delay period at different operating conditions.