Fault Criteria, Catalyst Damaging Misfire
|
|
Fault Criteria, Catalyst Damaging Misfire
|
Misfiring could be due to the fuel-air mixture that should have been burnt in the
engine being burnt in the three way catalytic converter instead.
The number of misfires that cause an overheated and consequently damaged three
way catalytic converter depends on engine load and speed.
An engine load and speed dependent matrix in the electronic control module's
memory specifies how many misfires per 200 engine revolutions will damage the three way
catalytic converter.
When the conditions for diagnosis are fulfilled, the combustion signals from the ignition
discharge module are evaluated. The fault criteria are satisfied when the number of misfires
per 200 engine revolutions exceeds the matrix value.
|
•
|
Ignition timing synchronized
|
|
1.
|
Max number of misfires allowed during 200
crankshaft revolutions
|
|
2.
|
Number of misfires detected ≥ max. number of permissible misfires during
200 engine revolutions.
|
|
3.
|
Combustion signals from the ignition cassette during 200 crankshaft
revolutions.
|
|
4.
|
Fault criteria for catalyst damaging misfire
fulfilled
|
