富氧进气改善林用小型汽油机动力性及经济性效果的分析

Effect on Dynamic Property and Fuel Economy Improvement of Small Gasoline Engines for Forestry with Oxygen-enriched Intake Air in Highland

以单缸风冷四冲程的林用小型汽油机为研究对象,采用气瓶供氧的方式,依次提供氧体积分数为21%的常态进气和氧体积分数分别为22%、23%、24%、25%和26%的5种富氧比例混合进气;保持节气门开度为25%不变,选择3 000、3 500、4 000、4 500、5 000和5 500 r/min共6个速度点,进行速度特性试验;保持转速为4 000r/min不变,选择0.5、1、1.5、2、2.5、3、3.5和4 kW共8个负荷点,进行负荷特性试验;待林用小型汽油机工作稳定后,测定其动力性和经济性指标数据并进行对比分析。试验结果表明,富氧进气能够提高吸入林用小型汽油机的混合气热值,提高其燃烧效率,增加其有效输出功率,增强其动力性能;同时能够提高林用小型汽油机的能量转化率,降低其燃油消耗率,达到优化其经济性能指标的目的;相对于氧体积分数为21%的常态进气,氧体积分数分别为22%、23%、24%、25%和26%的富氧进气条件下,各个转速点的功率平均升高率分别为6.1%、14.2%、20.6%、29.7%和38.9%,各个负荷点的油耗率平均降低率分别为8.8%、17.9%、24.8%、32.8%和42.9%;富氧进气能够同时改善林用小型汽油机的动力性及经济性,并且富氧进气的氧体积分数越高,改善的效果越明显。

Small gasoline engines for forestry with single cylinder air-cooled four stroke were selected as experimental objects and normal intake air with oxygen volume fraction of 21% and five kinds of oxygen-enriched mixture intake air with oxygen contents of 22%, 23%, 24%, 25% and 26% were provided in Oxygen cylinder. With 25% of the opening degree of throttle valve, six speed points of 3 000, 3 500, 4 000, 4 500, 5 000 and 5 500 r/min were selected to test the velocity characteristics. With 4 000 r/min, eight load points of 0.5, 1, 1.5, 2, 2.5,3, 3.5 and 4 kW were sdected to test the load characteristic. When the small gasoline engines for forestry worked stably, the dynamic property and the economy index were measured and compared. The test results show that oxygen-enriched intake air can improve mixture calorific value, combustion efficiency, effective output and dynamic property by small gasoline engines for forestry. Oxygen-enriched intake air can also improve energy transformation ratio, fuel consumption rate and economy index of small gasoline engines for forestry. Compared with normal intake air with oxygen content of 21%, the power of every speed point with oxygen contents of 22%, 23%, 24%, 25% and 26% increases by an average rate of 6.1%, 14.2%, 20.6%, 29.7% and 38.9%, respectively. The fuel consumption rate of every load point declines by an average rate of 8.8% , 17.9% , 24.8% , 32.8% and 42.9%, respectively. Oxygen-enriched intake air can improve both dynamic property and economy of small gasoline engines for forestry. The higher the oxygen concentrations are, the more obvious the improvements are.