Method and device for diagnosing coking in a secondary air system of an internal combustion engine
AssigneeVitesco Technologies GmbH
InventorJaroslav Lipa
Life of this patent
Estimating the term…
Abstract
The disclosure relates to a method and a device for diagnosing coking of a secondary air system of an internal combustion engine. The secondary air system has an intake air line for providing secondary air, a secondary air pump for compressing the secondary air, a secondary air valve for controlling the secondary air injection, a pressure sensor that is arranged in the secondary air system downstream of the secondary air pump and upstream of the secondary air valve, and an injection line for injecting the secondary air into an exhaust tract of the internal combustion engine.
Claims8
A method for diagnosing coking of a secondary air system of an internal combustion engine, the secondary air system has an intake air line for providing secondary air, a secondary air pump for compressing the secondary air, a secondary air valve for controlling a secondary air injection, a pressure sensor arranged in the secondary air system downstream of the secondary air pump and upstream of the secondary air valve, and an injection line for injecting the secondary air into an exhaust tract of the internal combustion engine, the method comprising:
- operating the internal combustion engine and activating the secondary air pump to pressurize secondary air situated between the secondary air pump and the secondary air valve, the secondary air valve being closed;
- opening the secondary air valve to inject the secondary air into the exhaust tract of the internal combustion engine;
- detecting a pressure profile by the pressure sensor, the pressure profile is characteristic of the pressure of the secondary air between the secondary air pump and the secondary air valve during the operation of the internal combustion engine;
- determining a maximum pressure value from the pressure profile;
- determining a mean pressure value from the pressure profile;
- comparing the maximum pressure value with the mean pressure value;
- and
- identifying that the secondary air system is coked if a result of the comparison of the maximum pressure value with the mean pressure value exceeds a predetermined threshold value,
- wherein the mean pressure value is determined within a specific time interval of the pressure profile, the time interval begins upon the opening of the secondary air valve, the specific time interval is greater than or equal to 50 milliseconds and less than or equal to 300 milliseconds, beginning after the opening of the secondary air valve.
A device for diagnosing coking of a secondary air system of an internal combustion engine, wherein the device comprises a control unit that is configured to control a method comprising:
- operating the internal combustion engine and activating a secondary air pump to pressurize secondary air situated between the secondary air pump and a secondary air valve, the secondary air system having an intake air line for providing secondary air, a secondary air pump for compressing the secondary air, the secondary air valve for controlling a secondary air injection, a pressure sensor arranged in the secondary air system downstream of the secondary air pump and upstream of the secondary air valve, and an injection line for injecting the secondary air into an exhaust tract of the internal combustion engine, wherein the secondary air valve is closed;
- opening the secondary air valve to inject the secondary air into the exhaust tract of the internal combustion engine;
- detecting a pressure profile by the pressure sensor, the pressure profile is characteristic of the pressure of the secondary air between the secondary air pump and the secondary air valve during the operation of the internal combustion engine;
- determining a maximum pressure value from the pressure profile;
- determining a mean pressure value from the pressure profile;
- comparing the maximum pressure value with the mean pressure value;
- and
- identifying that the secondary air system is coked if a result of the comparison of the maximum pressure value with the mean pressure value exceeds a predetermined threshold value,
- wherein the mean pressure value is determined within a specific time interval of the pressure profile, the time interval begins upon the opening of the secondary air valve, the specific time interval is greater than or equal to 50 milliseconds and less than or equal to 300 milliseconds, beginning after the opening of the secondary air valve.
Dependencies are inferred from the claim text.