Diagnostic Method: Notes

When the misfire occurred, the engine speed is decreased and the crankshaft position speed will change. Calculate the interval difference value (diagnostic value) from crankshaft position speed, and judge whether the misfire occurs or not comparing the calculated result with judgment value.

Calculate the diagnostic value (from crankshaft position speed)

--> Misfire detection every single ignition (Compare diagnostic value with judgment value) 180° Interval Difference Method 720° Interval Difference Method Pattern Recognition Method

--> NG judgment (Judge misfire occurrence required by the law) (Compare number of misfire with judgment) FTP 1.5 times misfire NG judgment Catalyst damage misfire NG judgment

For misfire detection, there are three methods such as 180° Interval Difference Method, 720° Interval Difference Method and Pattern Recognition Method.