PUMP PURGE FOR UREA DOSING SYSTEM

• US 20160040575A1
• Filed: 03/14/2014
• Published: 02/11/2016
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Cummins Incorporated
• Original Assignee: Cummins Incorporated
• Inventors: Chandrapati, Srivardhan, Naik, Mugdha, Huang, Wei, Muntean, George, Myer, Andrew, ZHANG, Shu, Rajagopalan, Srinivasa V.
• Granted Patent: US 9,689,291 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F01N 2610/02 the substance being ammonia or urea
• CPC Class Codes: F01N 2610/08 with prior mixing of the substances with a gas, e.g. air
• CPC Class Codes: F01N 2610/1406 Storage means for substances, e.g. tanks or reservoirs
• CPC Class Codes: F01N 2610/144 Control thereof
• CPC Class Codes: F01N 2610/1466 Means for venting air out of conduits or tanks
• CPC Class Codes: F01N 2610/1473 Overflow or return means for the substances, e.g. conduits or valves for the return path
• CPC Class Codes: F01N 2610/1493 Purging the reducing agent out of the conduits or nozzle
• CPC Class Codes: F01N 3/0871 Regulation of absorbents or adsorbents, e.g. purging by electrically controlling the supply of combustible mixture or its constituents only F02D41/0235
• CPC Class Codes: F01N 3/208 Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
• CPC Class Codes: F01N 3/30 Arrangements for supply of additional air control, e.g. using by-passes or variable air pump drives, F01N3/22
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

According to one embodiment, a diesel exhaust fluid purging system includes a metering valve with a supply port and a delivery port. The purging system also includes a pump assembly that is fluidly connected to the supply port of the metering valve. The pump assembly includes a pump and a single supply line that is fluidly connectable with a diesel exhaust fluid source. The purging system further includes an injection assembly that is fluidly connected to the delivery port of the metering valve. The injection assembly includes an air supply line that is fluidly connectable with an air supply source. Additionally, the purging system includes a controller in electrical communication with the metering valve, the pump assembly, and the injection assembly. The controller is configured to purge the pump assembly of residual diesel exhaust fluid using air from the air supply line.

Claims

1. A diesel exhaust fluid purging system, comprising:

a metering valve comprising a supply port and a delivery port;

a pump assembly fluidly connected to the supply port of the metering valve, the pump assembly comprising a pump and a single supply line fluidly connectable with a diesel exhaust fluid source;

an injection assembly fluidly connected to the delivery port of the metering valve, the injection assembly comprising an air supply line fluidly connectable with an air supply source; and

a controller in electrical communication with the metering valve, the pump assembly, and the injection assembly, the controller configured to purge the pump assembly of residual diesel exhaust fluid using air from the air supply line.

2. The system of claim 1, wherein the pump comprises an inlet and an outlet, the single supply line being fluidly connected to the pump inlet.

3. The system of claim 2, wherein the system further comprises an accumulation line that fluidly connects the pump outlet to the supply port of the metering valve, and a bypass line that fluidly connects the accumulation line to the supply line, the bypass line comprising a bypass valve.

4. The system of claim 3, wherein the injection assembly comprises:

a delivery line fluidly connected to the delivery port of the metering valve and fluidly connectable with an exhaust aftertreatment system; and

an air supply valve in the air supply line, wherein the air supply line is fluidly connected to the delivery line.

5. The system of claim 4, wherein the accumulation line comprises a vessel for containing pressurized fluid.

6. The system of claim 3, wherein the controller is configured to close the bypass valve of the bypass line and open the metering valve while the bypass line is closed to allow air from the air supply source to enter the accumulation line via the air supply line.

7. The system of claim 6, wherein the controller is configured to open the bypass valve of the bypass line to lower the pressure in the accumulation line before closing the bypass valve of the bypass line and opening the metering valve.

8. The system of claim 1, wherein the DEF source contains urea and water.

9. A method for purging a diesel exhaust fluid system having a diesel exhaust fluid source, a pump downstream of the source, a metering valve downstream of the pump, a bypass valve downstream of the pump and upstream of the metering valve, and an air supply valve downstream of the metering valve, the method comprising:

opening the bypass valve and the air supply valve;

after opening the bypass valve and the air supply valve, opening the metering valve;

after opening the metering valve, closing the metering valve;

after closing the metering valve, closing the bypass valve and the air supply valve; and

after closing the bypass valve and the air supply valve, actuating the pump.

10. The method of claim 9, wherein only a single fluid supply line receives diesel exhaust fluid from the diesel exhaust fluid source.

11. The method of claim 10, wherein only a single fluid supply line for diesel exhaust fluid source exists between the pump and the metering valve.

12. The method of claim 10, wherein only a single fluid supply line for diesel exhaust fluid source exists between the pump and the air supply valve.

13. The method of claim 9, further comprising predicting the presence of discrete columns of air in a fluid line between the diesel exhaust fluid source and the pump, wherein opening the bypass valve and the air supply valve occurs after predicting the presence of discrete columns of air in the fluid line.

14. The method of claim 9, wherein prior to opening the metering valve, pressurizing a fluid line between the metering valve and the air supply valve with pressurized air.

15. The method of claim 14, wherein only a single fluid supply line receives diesel exhaust fluid from the diesel exhaust fluid source, and wherein after opening the metering valve, purging the single fluid supply line of discrete columns of air with the pressurized air.

16. The method of claim 15, wherein a pressure of the pressurized air is greater than a pressure of diesel exhaust fluid in the single supply line.

17. A controller apparatus for a diesel exhaust fluid system, the system comprising a pump assembly fluidly connected to an injection assembly via a metering valve, the apparatus comprising:

an initialization module configured to receive system conditions;

a purge module configured to receive operating requests from the initialization module and send operating commands to purge the system, the purge module comprising;

an air supply module configured to control an air flow into the injection assembly,

a metering valve module configured to control air flow into the pump assembly for purging the pump assembly, and

a bypass valve module configured to control diesel exhaust fluid flow back into a diesel exhaust fluid source.

18. The apparatus of claim 17, further comprising a prime module configured to receive operating requests from the initialization module or the purge module and send operating commands to prime the system.

19. The apparatus of claim 17, wherein the purge module further comprises a diesel exhaust fluid source module configured to control a source of diesel exhaust fluid.

20. The apparatus of claim 17, wherein in response to operating commands to purge the system, the bypass module opens a bypass valve to allow diesel exhaust fluid to flow back into the diesel exhaust fluid source, the air supply module controls the air flow to build up air pressure downstream of the metering valve, and the metering valve module opens the metering valve to allow pressurized air downstream of the metering valve to flow into the injection assembly.