Method for small leak testing of an evaporative emissions system
AssigneeGM Global Technology Operations LLC
InventorTodd W Nelson
Life of this patent
Estimating the term…
Abstract
A method for small leak testing of an evaporative emissions system includes monitoring a vacuum pressure level of the evaporation emissions system with the engine on and actuating a canister vent valve to regulate the vacuum pressure level to a predetermined minimum vacuum pressure level. Upon turning the engine off, the canister vent valve and a canister purge valve are closed to seal the evaporative emissions system. Next, the vacuum pressure level is recorded over a predetermined time period after turning off the engine and a fault code is set when the vacuum pressure level becomes less than the predetermined minimum vacuum pressure level.
Claims15
A method for small leak testing of an evaporative emissions system of an engine, the method comprising:
- monitoring a vacuum pressure level of the evaporation emissions system with the engine on;
- opening a canister purge valve and activating a pump, both of which are within the evaporative emissions system, to provide a vacuum pressure level;
- actuating a canister vent valve within the evaporative emissions system to regulate the vacuum pressure level to a predetermined minimum vacuum pressure level;
- closing the canister vent valve and the canister purge valve when the engine is turned off;
- deactivating the pump;
- recording the vacuum pressure level over a predetermined time period after the engine is turned off and the pump is deactivated;
- and
- setting a fault code when the vacuum pressure level becomes less than the predetermined minimum vacuum pressure level.
A method for small leak testing of an evaporative emissions system of an engine, the method comprising:
- monitoring a vacuum pressure level of the evaporation emissions system with the engine on;
- opening a canister purge valve and activating a pump, both of which are within the evaporative emissions system, to provide the vacuum pressure level;
- actuating a canister vent valve within the evaporative emissions system with a variable pulse width modulated signal to regulate the vacuum pressure level to a predetermined minimum vacuum pressure level;
- closing the canister vent valve and the canister purge valve when the engine is turned off;
- deactivating the pump;
- recording the vacuum pressure level over a predetermined time period after the engine is turned off and the pump is deactivated;
- and
- setting a fault code when the vacuum pressure level becomes less than the predetermined minimum vacuum pressure level.
Dependencies are inferred from the claim text.