| 摘要 |
A method for diagnosing the fuel leakage of a car is provided to reduce maintenance costs by diagnosing the fuel leakage of respective injectors and displaying the diagnosed result using an external scanning tool, and to reduce maintenance time by easily diagnosing the leakage of an associated injector. A method for diagnosing the fuel leakage of a plurality of injectors of a car using an engine control unit includes the step of calculating(103) a first fuel injection calibrating coefficient when an engine is idle, comparing the calculated first fuel injection calibrating coefficient with a preset fuel calibrating critical value, and determining(101) that the fuel leaks from the plurality of injectors when the first fuel injection calibrating coefficient is the preset fuel calibrating critical value or more. When it is determined that the fuel leaks from the plurality of injectors, the fuel injection of the injectors is performed with a fuel amount which is set according to the theoretical air-fuel ratio. After a crank angle signal is received, engine roughness is calculated based on the crank angle signal and is stored as a reference value. Based on the reference value, a first critical value and a second critical value are calculated and stored. Next, after the fuel is injected with the fuel amount which is calibrated according to a predetermined second fuel injection calibrating coefficient, engine roughness is calculated based on the received crank angle signal. The calculated engine roughness is compared with the first critical value, and it is determined whether fuel leaks from one injector according to the compared result. Thereafter, the fuel leakage diagnosing result of one of the injectors is displayed through an external scanning tool, and it is determined whether the injector is the last injector or not. If the injector is not the last injector, the process proceeds the former step, so that it is determined whether fuel leaks from the subsequent injector. |
