The invention provides a method and equipment for judging misfire of a
diesel engine. The method comprises the steps that instant rotating speeds n of
crankshaft teeth corresponding to cylinders are collected in a working cycle; average angular speeds
omega of the cylinders are calculated due to the instant rotating speeds n of the
crankshaft teeth corresponding to the cylinders;
angular acceleration alpha among the cylinders is calculated with the average angular speeds
omega of the cylinders according to a formula as described in the specification;
omega1 is the average angular speed of the current cylinder; omega2 is the average angular speed of the previous cylinder;
delta t is a time sum corresponding to the
crankshaft teeth of the two cylinders; and whether the
angular acceleration alpha among the cylinders is smaller than a preset misfire threshold value is judged, if so, the current cylinder has the misfire, and otherwise, no cylinder has the misfire. As the
angular acceleration among the cylinders is obtained by collecting the instant rotating speeds of the crankshaft teeth in every working cycle, the accuracy of judging the misfire is improved. In addition, as the angular acceleration among the cylinders is obtained according to the difference between average angular speeds of the current cylinder and the previous cylinder, the angular acceleration among the cylinders can
resist signal interference of the individual cylinders effectively. The accuracy of judging the cylinders have the misfire is improved.