Leak detection method and system for a high pressure automotive fuel tank

A vapor management system for a vehicle comprising:

• a fuel tank;
• a vapor collection canister;
• a tank pressure control valve connected between the tank and canister, the control valve defining a high pressure side, including the fuel tank, and a low pressure side, including the canister;
• a vacuum source;
• a purge valve connected between the canister and vacuum source;
• a leak detection valve connected with the canister, the leak detection valve including a processor, and
• a pressure sensor and a temperature sensor, each disposed in a fuel vapor cavity of the fuel tank, with signals from the sensors being received by the processor, the pressure sensor being constructed and arranged to measure absolute pressure and the temperature sensor being constructed and arranged to measure absolute vapor temperature in the fuel tank,
• wherein, based on the absolute temperature measured by the temperature sensor, the processor is constructed and arranged to compare a predicted pressure in the fuel tank to the absolute pressure measured by the pressure sensor, and to identify a leak on the high pressure side if the predicted pressure is outside a tolerance range, while maintaining pressure in the fuel tank.

A vapor management system for a vehicle comprising:

• a fuel tank;
• means for collecting vapor;
• means for controlling pressure in the fuel tank, the means for controlling pressure being connected between the fuel tank and the means for collecting vapor, the means for controlling pressure defining a high pressure side, including the fuel tank, and a low pressure side, including the means for collecting vapor;
• means for providing a vacuum source;
• means for purging, connected between the means for collecting vapor and the means for proving a vacuum source;
• and
• a leak detection valve connected with the means for collecting vapor,
• means for processing data, and
• means for sensing absolute pressure and means for sensing absolute temperature, each means for sensing being disposed in a fuel vapor cavity of the fuel tank, with signals from each means for sensing being received by the means for processing,
• wherein, based on the absolute temperature measured from the means for sensing temperature, the means for processing compares a predicted pressure in the fuel tank to the absolute pressure measured by the means for sensing pressure, and identifies a leak on the high pressure side if the predicted pressure is outside a tolerance range, while maintaining pressure in the fuel tank.