Method, Device And Computer Program Product For Diagnosing An Oxidation Catalyst

An engine-driven vehicle comprising:

• an internal combustion engine;
• an exhaust gas aftertreatment system to which, during operation, the engine emits exhaust gases, the system comprising an oxidation catalyst for oxidation of NO into NO2, an injection device for injection of a reduction agent into the exhaust gas aftertreatment system upstream of the oxidation catalyst, an NOx-reducing catalyst, an NOx sensor arranged downstream of the NOx-reducing catalyst and the oxidation catalyst, a control unit for recording signals from the NOx sensor and for controlling at least the injection device, wherein the control unit is so arranged via the NOx sensor as to record a first value for the NOx content at a point in time before injection of the reduction agent and a second value for the NOx content at a point in time during a period when injection of the reduction agent takes place and poisons the oxidation catalyst, the control unit being arranged to compare the first and second values and to indicate impaired function of the oxidation catalyst when the difference between the measured values is less than a predetermined first value.

An engine-driven vehicle comprising:

• an internal combustion engine;
• an exhaust gas aftertreatment system to which the engine emits exhaust gases during operation, the system comprising an oxidation catalyst for oxidation of NO into NO2, an injection device for injection of a reduction agent into the exhaust gas aftertreatment system upstream of the oxidation catalyst, an NO2 sensor arranged downstream of the oxidation catalyst, a control unit for recording signals from the NO2 sensor and for controlling at least the injection device, the control unit being so arranged as to record a first value for the NO2 content via the NO2 sensor at a point in time before an injection of the reduction agent and a second value for the NO2 content at a point in time during the period when the injection of the reduction agent takes place and poisons the oxidation catalyst, in conjunction with which the control unit is so arranged as to compare the first and second measured values and to indicate impaired function of the oxidation catalyst when the difference between the measured values is less than a predetermined first value.