Rationality testing for a fuel vapor pressure management apparatus

A method of rationalizing the functioning of a fuel vapor pressure management system that is in fluid communication with a headspace of a fuel system, the fuel system supplying fuel to an internal combustion engine of a vehicle, the method comprising:

• providing a fuel vapor pressure management apparatus detecting an absence of leaks with respect to the headspace, the fuel vapor pressure management apparatus including:
• a housing defining an interior chamber;
• a pressure operable device separating the interior chamber into first and second portions, the pressure operable device including a poppet movable along an axis and a seal adapted to cooperatively engage the poppet, a first arrangement of the pressure operable device occurs during the leak detection test when there is a first negative pressure level in the first portion relative to the second portion and the seal is in a first deformed configuration, a second arrangement of the pressure operable device permits a first fluid flow from the second portion to the first portion when the seal is in a second deformed configuration, and a third arrangement of the pressure operable device permits a second fluid flow from the first portion to the second portion when the seal is in an undeformed configuration;
• and
• a sensor detecting the first arrangement of the pressure operable device during the leak detection test;
• counting a number of leak detection tests performed by the fuel vapor pressure management apparatus;
• counting a number of occurrences of the fuel vapor pressure management apparatus detecting an absence of a leak;
• and
• evaluating the number of occurrences within a selected number of tests.

A method of rationalizing the functioning of a fuel vapor pressure management system that is in fluid communication with a headspace of a fuel system, the fuel system supplying fuel to an internal combustion engine of a vehicle, the method comprising:

• providing a fuel vapor pressure management apparatus detecting an absence of leaks with respect to the headspace;
• counting a number of leak detection tests performed by the fuel vapor pressure management apparatus;
• counting a number of occurrences of the fuel vapor pressure management apparatus detecting an absence of a leak;
• and
• evaluating the number of occurrences within a selected number of tests, the evaluating including determining a statistical average of engine operating events when an absence of the leak occurs.