Diesel dosing system relief of trapped volume fluid pressure at shutdown

摘要

A diesel dosing system for a vehicle includes a control valve (31) controlling fluid flow to a dosing valve (32) for supplying fuel directly into an exhaust passage of the vehicle. A system pressure source (55) feeds the control valve. A shutoff valve (54) is fluidly connected to the pressure source downstream thereof and to the control valve upstream thereof. The shutoff valve permits bi-directional flow there-through. A connection (57) is between the shutoff valve and the control valve defining a fluid volume there-between. The shutoff valve permits fluid flow from the system pressure source through the connection and to the control valve during a regeneration phase of the system. Upon engine shutdown and based on fluid pressure in the volume, the shutoff valve opens so that fluid trapped in the volume will communicate with the pressure source thereby reducing the fluid pressure in the volume.