Fault criteria, emission-related misfiring
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Fault criteria, emission-related misfiring
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Misfiring may mean that exhaust emissions increase more than permitted.
The proportion of misfires causing prohibited exhaust emissions depends to a certain degree on the engine load and speed.
The number of misfires per 1000 engine revolutions required for the exhaust emissions to reach prohibited levels is stored in the control module memory in a matrix that is dependent on load and engine speed.
When the conditions for the diagnosis have been fulfilled, the combustion signals from the ignition discharge module are assessed. If the number of misfires per 1000 engine revolutions exceeds the value in the matrix, the fault criteria will have been fulfilled.
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1.
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Max. number of permissible misfires during 1000 engine revolutions
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2.
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Number of detected misfires ≥ max. number of permissible misfires during 1000 engine revolutions
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3.
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Combustion signals from ignition discharge module during 1000 engine revolutions
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4.
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Fault criteria for catalyst damaging misfiring fulfilled
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