Starting a spark-ignited engine with the gasoline―hydrogen mixture
Starting a spark-ignited engine with the gasoline―hydrogen mixture
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DOI：
10.1016/j.ijhydene.2011.01.020
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发表时间：
2011-04
影响因子：
7.2
通讯作者：
Shuofeng Wang;C. Ji;Bo Zhang
中科院分区：
文献类型：
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作者：
Shuofeng Wang;C. Ji;Bo Zhang
汽油机冷起动过程中，由于油膜效应的增强和燃烧温度的降低，会产生大量的HC和CO排放。试验研究了在汽油机中添加氢气对改善冷起动性能的影响。该试验是在一台1.6 L四缸SI发动机上进行的，该发动机配备有电子控制的氢气喷射系统。采用混合动力电子控制单元（HECU）控制氢气和汽油喷射器的开启和关闭。在相同的环境条件下，分别以纯汽油和汽油-氢气混合气起动发动机。在添加氢气后，调整汽油喷射持续时间，以确保发动机成功起动。所有冷启动实验均在17 °C的相同环境温度、冷却剂温度和油温下进行。试验结果表明，随着掺氢分数的增加，缸内压力和首循环平均指示压力均得到有效提高。发动机在前20个起动循环中的转速随着掺氢比的增加而增加。然而，在随后的循环中，由于采用了对发动机速度的闭环控制，在添加和不添加氢气的情况下，发动机速度仅略有变化。由于氢气的点火能量低，火焰传播速度快，氢气加入后，火焰发展和传播时间都缩短。添加氢气后，由于燃烧过程的增强，HC和CO排放显著下降。当氢气流量从0增加到2.5和4.3 L/min时，瞬时峰值HC排放分别从57083急剧降低到17850和15738 ppm。氮氧化物排放量增加，在第一个5秒，然后减少后，氢添加。
Because of the increased fuel-film effect and dropped combustion temperature, spark-ignited (SI) gasoline engines always expel large amounts of HC and CO emissions during the cold start period. This paper experimentally investigated the effect of hydrogen addition on improving the cold start performance of a gasoline engine. The test was carried out on a 1.6-L, four-cylinder, SI engine equipped with an electronically controlled hydrogen injection system. A hybrid electronic control unit (HECU) was applied to control the opening and closing of hydrogen and gasoline injectors. Under the same environmental condition, the engine was started with the pure gasoline and gasoline–hydrogen mixture, respectively. After the addition of hydrogen, gasoline injection duration was adjusted to ensure the engine to be started successfully. All cold start experiments were performed at the same ambient, coolant and oil temperatures of 17 °C. The test results showed that cylinder and indicated mean effective pressures in the first cycle were effectively improved with the increase of hydrogen addition fraction. Engine speed in the first 20 start cycles increased with hydrogen blending ratio. However, in later cycles, engine speed varied only a little with and without hydrogen addition due to the adoption of close loop control on engine speed. Because of the low ignition energy and high flame speed of hydrogen, both flame development and propagation durations were shortened after hydrogen addition. HC and CO emissions were dropped markedly after hydrogen addition due to the enhanced combustion process. When the hydrogen flow rate increased from 0 to 2.5 and 4.3 L/min, the instantaneous peak HC emissions were sharply reduced from 57083 to 17850 and 15738 ppm, respectively. NOx emissions were increased in the first 5 s and then reduced later after hydrogen addition.