| 摘要 |
A method of detecting an operation of a dosing injector in a urea SCR system is provided to easily detect malfunction of the dosing injector by measuring the temperature of exhaust gas. A method of detecting an operation of a dosing injector in a urea SCR(Selective Catalyst Reduction) system comprises the step of determining if the amount of dosing exceeds 500g/hr which is calculated based on the temperature of nitrogen oxides discharged from the urea SCR system and the catalyst. IF the amount of dosing exceeds 500g/ht, an electric signal is applied to the dosing injector through a control unit. If a differential temperature of exhaust gas is larger than 20degrees before and after the application of electrical signal, the dosing injector is determined as normal. The temperature drop is smaller than 20degrees and the amount of discharged nitrogen oxides is larger than 2000ppm, the dosing injector is determined as abnormal.
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