Pressure regulation via pump control for exhaust system

Abstract

A control system for a pump in a vehicle exhaust system includes a pump having an inlet port and an outlet port, a fluid supply in fluid communication with the inlet port, and a supply line in fluid communication with the outlet port. The supply line is configured to deliver fluid to an exhaust component. A controller is configured to adjust pump flow rate to maintain a desired pressure in the supply line. A restriction is utilized in a return flow path from the supply line.

1 . A control system for a pump comprising:
 a pump having an inlet port and an outlet port;   a fluid supply in fluid communication with said inlet port;   a supply line in fluid communication with said outlet port, said supply line configured to deliver fluid to an exhaust component; and   a controller configured to adjust a pump flow rate to maintain a desired pressure in said supply line.   
     
     
         2 . The control system according to  claim 1  including a return flow path configured to return fluid from said supply line to said pump, and including a restriction positioned within said return flow path. 
     
     
         3 . The control system according to  claim 2  wherein said restriction is positioned upstream of said fluid supply. 
     
     
         4 . The control system according to  claim 2  wherein said restriction comprises a fixed restriction. 
     
     
         5 . The control system according to  claim 4  wherein said fixed restriction comprises an orifice having an opening defined by a fixed size. 
     
     
         6 . The control system according to  claim 2  wherein fluid flows through said restriction any time said pump is active. 
     
     
         7 . The control system according to  claim 2  including a pressure sensor downstream of said pump outlet and upstream of said restriction, said pressure sensor measuring pressure in said supply line and communicating measured pressure to said controller. 
     
     
         8 . The control system according to  claim 7  wherein said controller adjusts said pump flow rate in response to said measured pressure. 
     
     
         9 . The control system according to  claim 8  wherein said controller adjusts said pump flow rate by selectively adjusting pump speed to maintain said desired pressure. 
     
     
         10 . The control system according to  claim 2  wherein said restriction limits a return flow rate to said pump resulting in an increase in pressure in said supply line, and wherein a pressure achieved in said supply line when said pump is at a maximum flow rate is higher than said desired pressure. 
     
     
         11 . A fluid supply control system for a vehicle exhaust system comprising:
 a pump having an inlet port and an outlet port;   a fluid supply in fluid communication with said inlet port;   a supply line in fluid communication with said outlet port, said supply line configured to deliver fluid to an exhaust component;   a pressure sensor configured to measure pressure in said supply line and generate a measured pressure signal;   a return flow path configured to return fluid from said supply line to said pump;   a fixed restriction positioned within said return flow path; and   a controller configured to adjust a pump flow rate to maintain a desired pressure in the supply line based on said measured pressure signal.   
     
     
         12 . The fluid supply control system according to  claim 11  wherein said supply line supplies fluid to an injector that injects fluid into an exhaust gas stream within said exhaust component. 
     
     
         13 . The fluid supply control system according to  claim 11  wherein said fixed restriction comprises an orifice having an opening defined by a fixed size, and wherein fluid flows through said orifice any time said pump is powered. 
     
     
         14 . The fluid supply control system according to  claim 11  wherein said exhaust component comprises one of a SCR component or DPF component. 
     
     
         15 . A method of controlling a pump in a vehicle exhaust system comprising:
 providing fluid from a fluid supply to a pump inlet;   pumping fluid into a supply line via a pump outlet;   supplying fluid from the supply line to a vehicle exhaust component; and   adjusting a pump flow rate to maintain a desired pressure in the supply line.   
     
     
         16 . The method according to  claim 15  including restricting return flow to said pump to increase pressure in said supply line. 
     
     
         17 . The method according to  claim 16  including configuring a restriction in a return flow path to have an opening defined by a fixed size. 
     
     
         18 . The method according to  claim 17  including configuring the restriction such that fluid flows through the return path any time the pump is activated.