초록 ▼

A leak detection method for an on-board evaporative emission leak detection system that detects leakage from an evaporative emission space of a fuel system of an automotive vehicle. During a leak detection test, a vent valve closes, and a purge valve, that selectively communicates the evaporative em

A leak detection method for an on-board evaporative emission leak detection system that detects leakage from an evaporative emission space of a fuel system of an automotive vehicle. During a leak detection test, a vent valve closes, and a purge valve, that selectively communicates the evaporative emission space with the engine intake manifold, opens to cause vacuum to be drawn in the evaporative emission space. A vacuum regulator valve regulates evaporative emission space vacuum to a defined vacuum. Subsequently, the purge valve closes. Loss of vacuum, indicative of leakage, is signaled by a pressure sensor. An algorithm detects a substantially constant rate of vacuum loss and then measures the amount of loss over a defined time interval. That measurement is then compensated for volume of the evaporative emission space and rate of fuel volatilization to arrive at a value forming a basis for making a leakage determination.

대표청구항 ▼

[ What is claimed is:] [1.] A leak detection test method for an evaporative emission space of a fuel storage system of an automotive vehicle comprising:creating a differential between pressure in an evaporative emission space and atmospheric pressure and regulating, by a regulator valve, the created

[ What is claimed is:] [1.] A leak detection test method for an evaporative emission space of a fuel storage system of an automotive vehicle comprising:creating a differential between pressure in an evaporative emission space and atmospheric pressure and regulating, by a regulator valve, the created differential to a defined differential sufficient to perform a leak detection test on the evaporative emission space;isolating the evaporative emission space so that reduction in the regulated created differential is indicative of leakage from the evaporative emission space; andsensing reduction in the regulated created differential;in which the step of creating a differential between pressure in an evaporative emission space and atmospheric pressure and regulating, by a regulator valve, the created differential to a defined differential sufficient to perform a leak detection test on the evaporative emission space comprises creating vacuum in the evaporative emission space and regulating the created vacuum to a regulated vacuum by a vacuum regulator valve.