Diesel Dosing System Relief Of Trapped Volume Fluid Pressure At Shutdown

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, and
• a shutoff valve fluidly connected to the pressure source downstream thereof and to the control valve upstream thereof so as to define a fluid volume between the shutoff valve and control valve, the shutoff valve permitting fluid flow from the system pressure source through the volume 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.

A diesel dosing system for a vehicle, the diesel dosing system comprising:

• 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 as to define a fluid volume between the shutoff valve and control valve, the shutoff valve being constructed and arranged to permit fluid flow from the system pressure source through the volume and to the control valve during a regeneration phase of the system,
• wherein upon engine shutdown and based on fluid pressure in the volume, the shutoff valve is constructed and arranged to open so that fluid trapped in the volume will communicate with the pressure source thereby reducing the fluid pressure in the volume, and
• wherein when the shutoff valve is closed, no fluid in the volume can communicate with the pressure source.