| 摘要 |
A fuel system leakage detector (1) includes a pressure source (3) and a test head (4) adapted to be coupled to a fuel system (17) of a vehicle (19) with engine (21), fuel tank (18), fuel filler neck (20), fuel closure cap (16) and evaporative emissions cannister (24), such fuel systems leakage detector also having a pneumatic circuit (5) coupled to a pressure source (3) and the test head (4), a pneumatic circuit bypass (2) coupled to the pressure source (3) and the test head (4), and a signaling device (7). The pneumatic circuit (5) includes a measurement device (6) coupled to the signaling device through which pressurized gas flows during leakage testing. Before testing, pressurized gas is diverted through the pneumatic circuit bypass (2) and bypasses the pneumatic circuit including the measurement device (6) to charge the test head (4) and the fuel system (17) for testing. The measurement device (6) then detects gas pressure differences between the test head (4) and the atmosphere whereby the signaling device (7) indicates the results of the leakage test.
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