초록 ▼

A method and apparatus is provided for monitoring the operation of a NOx storage catalytic converter in the exhaust stream of an internal combustion engine. The NOx content of the gas stream upstream and downstream of the catalytic converter is measured and used to determine storage efficiency. This

A method and apparatus is provided for monitoring the operation of a NOx storage catalytic converter in the exhaust stream of an internal combustion engine. The NOx content of the gas stream upstream and downstream of the catalytic converter is measured and used to determine storage efficiency. This is compared to a threshold value, and if the threshold value is not met a regeneration process is performed. The storage value is measured after regeneration to determine if the catalytic converter is faulty.

대표청구항 ▼

1. Exhaust gas purification device for a lean-running internal combustion engine comprisinga) an NOx storage catalytic converter; b) a oxygen contact sensor upstream of the NOx storage catalytic converter; c) an NOx sensor upstream of the NOx storage catalytic converter for determining the NOx conce

1. Exhaust gas purification device for a lean-running internal combustion engine comprisinga) an NOx storage catalytic converter; b) a oxygen contact sensor upstream of the NOx storage catalytic converter; c) an NOx sensor upstream of the NOx storage catalytic converter for determining the NOx concentration in the exhaust flowing into the NOx storage catalytic converter (14); d) an NOx sensor downstream of the NOx storage catalytic converter; e) an analysis unit for the sensor signals; f) a lambda sensor arranged downstream of the NOx storage catalytic converter; and g) a control unit for monitoring operation of said NOx storage catalytic converter, by carrying out the method of: a. determining NOx exhaust gas concentrations upstream and downstream of said catalytic converter; b. determining an NOx storage efficiency ETANOX from said NOx exhaust gas concentrations; c. comparing said NOx storage efficiency ETANOX with a threshold value NOx MAX and determining if said threshold value is not met; d. if said threshold value is not met performing at least one regeneration step selected form NOx regenerating and desulfating; e. repeating the determination of storage efficiency according to steps a and b to derive a new value of storage efficiency; f. comparing said new value to said threshold value NOx MAX; and g. if said new value does not meet said threshold value, signalizing a catalytic converter fault.