农用单缸柴油机喷醇器流量特性试验研究

Experimental study on flow characteristics of methanol injector of agricultural single cylinder diesel engine

采用进气道甲醇电控喷射方式,在农用单缸柴油机中掺烧甲醇,喷醇压力和甲醇温度会改变每循环喷醇量,直接影响单缸柴油机甲醇的掺烧比。采用试验的方法,在不同喷射压力、甲醇温度条件下,测量喷醇器流量随喷醇脉宽的变化规律,对循环喷醇量特性进行分析,采用数值分析的方法,提出循环喷醇量的修正MAP。结果表明,脉宽在0~0.5 ms喷醇器处于无效喷射阶段,0.5~1.5 ms循环流量随脉宽增大呈非线性增加,脉宽大于1.5 ms,循环流量随脉宽增大基本呈线性增长;循环喷醇量随喷醇压力和甲醇温度的提高而增大,1.5~10 ms阶段,喷射压力每提升25 kPa,循环流量平均提高4.8%,甲醇温度每提升15℃,循环流量平均提高3.2%;喷醇压力和甲醇温度变化时,提出的修正MAP能够有效对喷醇量进行校正。

Using the inlet methanol electronically controlled injection mode, methanol is mixed combustion in the agricultural single cylinder diesel engine, the injection pressure and temperature of methanol will change the amount of methanol injected in each cycle, which directly affects the methanol mixing ratio of the single cylinder diesel engine. Using the experimental method, under the conditions of different injection pressure and methanol temperature, the variation law of methanol injector flow with methanol injection pulse width was measured, the flow characteristics were analyzed, and a modified MAP of methanol circulating injection volume was proposed. The results showed that the methanol injector was in the invalid injection stage when the pulse width was 0-0.5 ms. The circulating flow rate of 0.5-1.5 ms increased nonlinearly with the increase of pulse width. When the pulse width was greater than 1.5 ms, the circulating flow rate increased linearly with the increase of pulse width. The circulating flow increased with the increase of the injection pressure and temperature of methanol, in the stage of 1.5-10 ms, the circulating flow increased by 4.8% on average every time the injection pressure increased by 25 kPa, and the circulating flow increased by 3.2% on average every time the methanol temperature increased by 15 ℃. When the injection pressure and methanol temperature changed, the proposed modified MAP could effectively correct the methanol injection amount.