Patent ID: 7194893

Claim:
A method for evaporative leak detection of an automotive vehicle fuel system including a tank having vapor at a known pressure at a first point in time, the method comprising: supplying from the tank fuel being combusted by the automotive vehicle; measuring and recording a first temperature of the vapor at substantially the first point in time, which is not during the supplying; measuring and recording a second temperature and a measured pressure of the vapor at a second point in time, which is not during the supplying; computing a temperature-compensated pressure based on previously measured values; and comparing the temperature-compensated pressure with the measured pressure at a second point in time to detect a leak, wherein the temperature-compensated pressure is computed as a function of the known pressure at the first point in time and of the measured temperatures, wherein the function comprises: P c =P 1 (2− T 2 /T 1 ) where P c is the temperature-compensated pressure, T 1 is the first temperature at the first point in time and T 2 is the second temperature at the second point in time.