Patent ID: 7006912
Filing Date: 2006-02-28
Classification: G01M

Abstract:
1. System for diagnosing cylinder misfiring in an internal combustion engine, comprising: an engine position sensor producing a position signal indicative of an engine crankshaft position relative to a reference position; means responsive to the position signal for determining a number of timing parameters each indicative of a contribution of a corresponding one of the engine cylinders to an overall rotational speed of the engine; means for collecting first values of the number of timing parameters while a first percentage of fuel relative to 100% fueling is being supplied to each of the cylinders; means for collecting second values of the number of timing parameters while a second percentage of fuel relative to 100% fueling is being supplied to each of the cylinders; means for determining a reference timing value as a function of one or more of the second values of the number of timing parameters; and means for identifying as firing normally any cylinder having a corresponding first value of the number of timing parameters that deviates in a first direction from the reference timing value.