| 摘要 |
Disclosed is a method of detecting degradation in cam profile switching in a engine comprising assigning a delay between starting an engine diagnostic mode and detecting the exhaust emissions for analysis downstream of combustion. Delaying the measurement of the diagnostic parameters enables the engine to only briefly enter a diagnostic mode. Several different methods are contemplated. The methods are: detecting degradation in a cam profile switching system in an internal combustion engine comprising detecting from a look up table the transit time of exhaust gases from a combustion chamber to a sensor; detecting degradation in a cam profile switching system in an internal combustion engine comprising detecting from an algorithm the transit time of exhaust gases from a combustion chamber to a sensor; detecting degradation in a cam profile switching system in an internal combustion engine comprising counting engine revolutions corresponding to the transit time of exhaust gases from a combustion chamber to a sensor; detecting degradation in a cam profile switching system in an internal combustion engine comprising determining the mass of fuel entering a combustion chamber; detecting degradation in a cam profile switching system in an internal combustion engine comprising determining the mass of air entering a combustion chamber; detecting degradation in a cam profile switching system in an internal combustion engine comprising determining the mass of air/fuel mixture entering a combustion chamber. |
