Dashpot: Description and Operation

Fig. 10 Dash Pot System:

Fig. 11 Dash Pot System Schematic:

The Dash Pot reduces Hydrocarbons (HC) and Carbon Monoxide emissions by returning the throttle plate slowly to the idle position during deceleration. This allows the air fuel mixture to burn more completely than if the throttle were closed abruptly. The Dash Pot consists of a spring loaded diaphragm that extends when the throttle is opened, thus drawing in air through suction. The air becomes trapped by the vacuum transmitting valve (VTV) and becomes a buffer on the diaphragm. When the throttle valve is released and comes in contact with the DP actuator pin, the air is forced back out of the DP filter slowly, returning the throttle valve slowly to its idle position.