张强, 隆武强, 田江平.JCCI发动机全工况燃烧和排放特性研究[J].内燃机工程,2017,38(3):34-40. |
JCCI发动机全工况燃烧和排放特性研究 |
Combustion and Emissions Characteristics of JCCI Engine at All Conditions |
DOI: |
关键词:内燃机 射流 预混合 压缩着火 |
Key Words:IC engine jet premixed compression ignition |
基金项目:国家自然科学基金项目(51379034) |
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摘要:将一台单缸农用柴油机压缩比降至12, 在缸盖上增加一个带液化石油气(LPG)供给通道和火花塞的点火室, 将其改造为射流控制压缩着火(jet controlled compression ignition, JCCI)发动机, 研究了全工况范围点火正时和负荷对JCCI发动机燃烧可控性的影响。试验结果表明:在大多数工况范围内, 柴油预混合气的燃烧始点相位θ10和燃烧中点相位θ50随点火正时单调变化, 且滞燃期对负荷不敏感, 说明其着火相位可以通过点火正时直接控制;在接近全负荷工况时, 滞燃期迅速缩短, 部分柴油提前发生自燃, 射流对着火相位的影响减弱;在大多数工况范围内, NOx和碳烟排放均较低, 且对点火正时敏感, 减小点火提前角可以显著降低NOx和碳烟排放, 但是HC和CO排放较高。 |
Abstract:An experimental study on jet controlled compression ignition(JCCI) engine was conducted at all conditions on a prototype engine that was modified from a single cylinder diesel engine. The engine compression ratio was reduced to 12 to avoid auto-ignition of premixed diesel, and a small ignition chamber comprising a gas fuel injector and a spark plug was mounted on the cylinder head. Experiments were conducted at all loads to study the influences of ignition timing and load on the combustion controllability of a JCCI engine. The experimental results show that the combustion initial pointθ10 and middle point θ50 (referring to crank angles that correspond to 10% and 50% of total heat release) of premixed diesel change in one direction at most conditions. Its ignition delay is insensitive to load variation, indicating that a direct control of ignition timing for premixed combustion can be expected. However, the ignition delay starts to be reduced quickly at a point near full load due to an unexpected auto-ignition of premixed diesel. Therefore the effect of jet on the controllability of the ignition timing is weakened. The NOx and smoke are maintained at a low level at most conditions and they can be reduced greatly by advancing the spark timing due to their sensitivity to it. However, HC and CO are higher. |
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