Patent ID: 7721533

Claim:
A method of controlling pressure in a diesel dosing system for a vehicle, the method comprising: providing a diesel dosing system including: a control valve controlling fluid flow to a dosing valve, the dosing valve being coupled directly with an exhaust passage of the vehicle and having structure movable from a closed position to an open position to supply fuel directly into the exhaust passage, a system pressure source feeding the control valve, a shutoff valve fluidly connected to the pressure source downstream thereof and to the control valve upstream thereof, the shutoff valve permitting bi-directional flow there-through, and a connection between the shutoff valve and the control valve defining a fluid volume there-between, the shutoff valve permitting fluid flow from the system pressure source through the connection and to the control valve during a regeneration phase of the system, and under engine shutdown conditions and under certain fluid pressure in the volume, permitting the shutoff valve to open so that fluid trapped in the volume will communicate with the pressure source thereby reducing the fluid pressure in the volume, and when the shutoff valve is closed, ensuring that no fluid in the volume communicates with the pressure source.