斜轴涡流对汽油机低速低负荷燃烧过程影响的试验研究

Experimental Study on Effect of Inclined Swirl on Combustion Process of a Gasoline Engine at Low Speed and Load

研制了一套四气门汽油机可变斜轴涡流系统,在发动机试验台上利用CB-466燃烧分析仪研究了斜轴涡流特性对低速低负荷燃烧过程的影响。研究结果表明,低转速、低负荷时,指示热效率随着斜轴涡流比和斜轴涡流倾角的增加先增加后减小,当斜轴涡流比为0．76、斜轴涡流倾角为55．7°时,指示热效率最大。中等转速、低负荷时,指示热效率随着斜轴涡流比和斜轴涡流倾角的增加逐渐增加,当斜轴涡流比和斜轴涡流倾角最大时指示热效率最大。低转速和负荷时,平均指示压力随着斜轴涡流比和斜轴涡流倾角的增加先增加后减小,当斜轴涡流比为0．76、斜轴涡流倾角为55．7°时,平均指示压力最大。不同转速时,最高燃烧压力随斜轴涡流比和斜轴涡流倾角的变化规律各不相同,但相同转速下,不同负荷时的最高燃烧压力随斜轴涡流比和斜轴涡流倾角的变化规律大致是相同的。

Variable inclined swirl system of a four-valve gasoline engine was developed. The effect of inclined swirl on combustion process of a four-valve engine at low speed and load were analyzed with the CB-466 combustion analyzer on engine test-bed. The results show that the indicated thermal efficiency increases at initial stage and decreases gradually with the increase of inclined swirl ratio and inclined swirl angle at low speed and loads. Indicated thermal efficiency reaches the maximum value at inclined swirl ratio of 0.76 the inclined swirl angle of 55.7°. At medium speed and light load, the indicated thermal efficiency increases gradually with the increase of inclined swirl ratio and inclined swirl angle, and reaches the maximum value at maximum inclined swirl ratio and maximum inclined swirl angle. The indicated mean pressure increases at initial stage and decreases gradually with the increase of inclined swirl ratio and inclined swirl angle at low speed and load, and it reaches the maximum value at inclined swirl ratio of 0.76 and inclined swirl angle of 55.7°. At different engine speeds, the combustion peak pressure shows different variation with inclined swirl ratio and inclined swirl angle, while at the same speed, the combustion peak pressure gives similar behavior with variation of inclined swirl ratio and inclined swirl angle at different loads.