Catalyst Damaging Misfires

A rapid response to misfires that could potentially damage the catalyst is necessary. The monitoring interval here (as shown in Figure) is equivalent to 200 crankshaft revolutions. Analogous to emissions relevant misfires, cylinder specific counters fzkatzyl_0... fzkatzyl_7  and the sums total counter in bank 1 fzkatsb_w_0  and bank2 fzkatsb_w_1  are used as shown in Figure and for detecting catalyst damaging misfires.

At each misfire event the sum counter is incremented depending on a load and engine speed dependent weighting factor.

In order to protect the catalyst fuel injection will be shut off immediately at cylinders that are responsible for or contribute to a catalyst damaging misfiring rate. If more than one cylinder is misfiring, both the cylinder-individual fault entry and a "multiple misfiring" entry will be carried out (see). Each cylinder that individually has more than 10% of all detected misfires is identified.