Fuel vapor purge control

Reference Number: N 01-05

Inventors: DeLand, Daniel L.; Detweiler, Charles A.

Owner: NISTAC

USPTO Link: 5970958

Invention Summary

It is a primary object of the present invention to overcome the disadvantages of the prior art and provide an electronically controlled variable area purge valve and pressure regulator that is less costly to manufacture and which minimizes the effects of inlet pressure and manifold vacuum on the performance of the purge regulator. As a related object, the variable area purge valve and pressure regulator of the present invention combines a solenoid valve assembly and a pressure regulator assembly for generating an output flow characteristic that varies as a function of the duty cycle of the electronic control signal and which is independent of variations in the inlet pressure and manifold vacuum.

Another object of the present invention is to provide a variable area purge regulator which utilizes a pressure regulator assembly to maintain a substantially constant pressure differential across the variable area purge control valve during operation thereof. One side of the pressure regulator assembly is referenced to the canister or inlet side of the system so that inlet pressure in the system will tend to close the regulator more tightly.

A further object of the present invention is to provide a variable area purge valve and pressure regulator which is operative without a bleed flow existing therethrough while being capable of satisfying the desired performance specifications across the entire range of engine operating conditions and is not susceptible to adverse environmental conditions.