简述点火提前角！影响点火提前角的因素「干货」

简述 点火提前角

定义：从点火时刻起到活塞到达压缩上止点，这段时间内曲轴转的角度称为点火提前角。

影响点火提前量最大的因素是 转速。随着转速的上升，转过同样角度的时间变短，只有更大的提前角才能得到相应的提前时间。

理论上最小点火提前角为0度，但为了防止在进气行程点燃进气，往往设为5度以上，这也是启动转速所需要的角度。

影响因素：1.缸温缸压。越高燃烧越快，点火提前角要越小。影响缸温缸压的因素有：发动机压缩比、气温、缸温、负荷；2.汽油辛烷值，也就是汽油牌号，越高抗爆震能力越强，相应允许更大的点火提前角；3.燃气混合比。过浓过稀燃烧速度皆慢，需增加点火提前角。

影响点火提前角的因素

点火提前角是发动机运转关键参数之一，它与汽车的动力、油耗和排放有密切关系。点火提前角的大小对发动机的工作效率和性能有很大的影响，那么有哪些因素会影响点火提前角呢？

第一，发动机转速是影响点火提前角的重要因素之一。由于火花塞在不同转速下产生火花所需的时间不同，因此点火提前角也需要相应的调整，使得点火时间始终处于最优范围内。

第二，空气流量也是影响点火提前角的因素之一。在同样的燃料供给下，空气流量的大小会影响燃烧的效率，从而影响点火提前角的大小。

第三，进气温度也是影响点火提前角的因素之一。随着进气温度的升高，空气密度会降低，从而导致燃烧效率的下降，也会影响点火提前角的调整。

第四，燃料品质也会影响点火提前角。燃料的品质越好，就会有更高的燃烧速度和更高的热值，从而可以进行更好的燃烧和更高的点火提前角。

【英文介绍/For English】：

Definition: From the moment of ignition to when the piston reaches the compression top dead center, the angle of the crankshaft during this period is called the ignition advance angle.

The biggest factor affecting the ignition advance is the rotational speed. As the speed increases, the time to turn the same angle becomes shorter, and only with a larger advance angle can the corresponding advance time be obtained.

In theory, the minimum ignition advance angle is 0 degrees, but in order to prevent the intake air from being ignited during the intake stroke, it is often set to more than 5 degrees, which is also the angle required for the starting speed.

Influencing factors: 1. Cylinder temperature and cylinder pressure. The higher the combustion speed, the smaller the ignition advance angle. Factors affecting cylinder temperature and cylinder pressure include: engine compression ratio, air temperature, cylinder temperature, and load; 2. The octane number of gasoline, that is, the grade of gasoline, the higher the anti-knock ability, the greater the ignition advance angle is allowed; 3. Gas mixing ratio. Too rich and too lean will burn slowly, so it is necessary to increase the ignition advance angle.