Movable diaphragm bidirectional noise reduction cannister vent solenoid (cvs) valve

A solenoid valve comprising:

• a bobbin configured to support a coil;
• an armature movably disposed relative to the bobbin;
• a valve body having a first port and a second port and defining a valve seat;
• a plunger, a top of the plunger being coupled to the armature, the plunger comprising a longitudinal shaft and a first radially extending flange extending radially relative to the longitudinal shaft and between top of the plunger and a bottom of the plunger and a second radially extending flange extending radially relative to the longitudinal shaft between the first radially extending flange and the bottom of the plunger, the plunger being movable with the armature between a closed position wherein fluid communication from the first port to the second port is blocked and an open position wherein fluid communication from the first port to the second port is allowed;
• a seal coupled to the plunger, the seal being engaged with the valve seat when the plunger is in the closed position and away from the valve seat when the plunger is in the open position;
• a spring coupled to the plunger for biasing the plunger to the open position;
• and
• a diaphragm, the diaphragm being elastomeric and having an opening therethrough for receiving the longitudinal shaft with the longitudinal shaft being spaced from the opening by a gap to allow the longitudinal shaft to freely move within the opening, the opening being disposed between the first radially extending flange and the second radially extending flange, the diaphragm comprising:
• an exterior side wall extending between a top and a bottom of the diaphragm:
• and
• a bottom cover,
• the top of the diaphragm being open and the bottom cover partially closing the bottom of the diaphragm,
• the bottom cover comprising a central section defining the opening and defining an undulation between the exterior side wall and the opening,
• the exterior side wall having a first height, the undulation having a second height and the central section having a third height, the first height being greater than the second height and the second height being greater than the third height,
• the first radially extending flange being positioned to contact the diaphragm as the plunger is moved to the closed position and after a first portion of a stroke of the plunger in which the longitudinal shaft moves freely through the opening, whereby contact of the diaphragm by the first radially extending flange causes elastic deformation of the diaphragm in the direction of the valve seat to reduce a speed of travel of the plunger as the plunger is moved to the closed position, and
• the spring being configured to force the plunger to the open position a rate faster than a rate at which the diaphragm recovers from the elastic deformation, whereby the second radially extending flange contacts the diaphragm to reduce a speed of travel of the plunger as the plunger is moved to the open position.

An evaporative emission system comprising:

• an evaporation canister coupled to a fuel tank for receiving fuel vapor from the fuel tank;
• and
• a canister vent valve fluidly coupled to atmospheric air and the evaporation canister;
• the canister vent valve comprising:
• a bobbin configured to support a coil;
• an armature movably disposed relative to the bobbin;
• a valve body having a first port and a second port and defining a valve seat;
• a plunger, a top of the plunger being coupled to the armature, the plunger comprising a longitudinal shaft and a first radially extending flange extending radially relative to the longitudinal shaft and between top of the plunger and a bottom of the plunger, the plunger being movable with the armature between a closed position wherein fluid communication from the first port to the second port is blocked and an open position wherein fluid communication from the first port to the second port is allowed;
• a spring coupled to the plunger for biasing the plunger to the open position;
• and
• a diaphragm, the diaphragm being elastomeric and having an opening therethrough for receiving the longitudinal shaft with the longitudinal shaft being spaced from the opening by a gap to allow the longitudinal shaft to freely move within the opening, the opening being disposed between the first radially extending flange and the bottom of the plunger,
• the first radially extending flange being positioned to contact the diaphragm as the plunger is moved to the closed position and after a first portion of a stroke of the plunger in which the longitudinal shaft moves freely through the opening, whereby contact of the diaphragm by the first radially extending flange causes elastic deformation of the diaphragm in the direction of the valve seat to reduce a speed of travel of the plunger as the plunger is moved to the closed position, and
• the spring being configured to force the plunger to the open position a rate faster than a rate at which the diaphragm recovers from the elastic deformation, whereby the plunger contacts the diaphragm to reduce a speed of travel of the plunger as the plunger is moved to the open position.