not utilize a pressure regulator for the purpose of dampening purge flow pulsations rather the creation of a predetermined pressure differential acting across valve 14 u2032 enables a given command signal to directly provide the intended flow rate free of manifold vacuum variations it is believed that this can eliminate the need for the engine management computer to include a map for processing an input representing intake manifold vacuum when it calculates what the command signal to the solenoid coil of the valve should be 0052 fig5 shows a series of representative graph plots of purge flow rate through valve 14 u2032 vs time averaged d c current flow in the solenoid coil each graph plot corresponds to a different value of intake manifold vacuum as indicated in fig5 but the important effect of pressure regulator 200 can be seen by the substantial congruence of graph plots for 200 300 400 500 and 600 mm hg intake manifold vacuum in the examples of fig5 purge flow commences at about 183 milliamps current for the substantially congruent plots 0053 fig6 and 7 illustrate another embodiment in which an lspv and a pressure regulator are integrated into a single assembly like reference numerals from the preceding figs are used to identify like parts although from comparison of it can be seen that certain parts differ in certain details of construction fig6 and 7 show that pressure regulator 200 has been integrated into the lower end.