Reductant delivery apparatus with purging means

• US 8,931,259 B2
• Filed: 09/02/2012
• Issued: 01/13/2015
• Est. Priority Date: 09/02/2011
• Status: Active Grant

• Current Assignee: Baohua Qi, Mi Yan
• Original Assignee: Baohua Qi, Mi Yan
• Inventors: Yan, Mi, Qi, Baohua
• Primary Examiner(s): BOGUE, JESSE SAMUEL
• Application Number:
  US13/602,195
• Publication Number:
  US 20130055701A1
• Time in Patent Office: 863 Days
• Field of Search: 60272-324
• US Class Current: 60/286
• CPC Class Codes: F01N 2610/1466 Means for venting air out of conduits or tanks
• CPC Class Codes: F01N 3/208 Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A dosing apparatus with purging means for delivering reductant into an exhaust gas treatment system of an internal combustion engine. The apparatus includes a first Venturi T connector with two high pressure ports and a low pressure port, and a purge control valve for switching from normal dosing to purging by controlling flow through the two high pressure ports. The apparatus may also include a second Venturi T connector and a reductant supply chamber for purging reductant residue in its pump and reductant passage lines. The apparatus may further include a purging controller that triggers a purging event according to engine oil or coolant temperature and controls the purging process after a dosing process completes.

Claims

1. A dosing apparatus delivering reductant to an exhaust gas treatment system of an internal combustion engine, comprising:

a Venturi T connector with a first high pressure port, a second high pressure port, and a low pressure port, at which a low pressure is created when a fluid flows through said first high pressure port and said second high pressure port;

a buffer chamber fluidly coupled to said low pressure port of said Venturi T connector;

an injector fluidly coupled between said buffer chamber and an exhaust line for controlling reductant dosing rate;

a pump fluidly coupled to said first high pressure port of said Venturi T connector for supplying reductant; and

a control valve fluidly connected to said second high pressure port of said Venturi T connector for controlling a reductant flow passing therethrough.

2. The dosing apparatus of claim 1, further comprising:

a purge controller configured to operate said control valve open after a dosing process completes.

3. The dosing apparatus of claim 2, wherein said purge controller is further configured to operate said control valve open after a delay time since a dosing process completes.

4. The dosing apparatus of claim 3, wherein said purge controller is further configured to determine said delay time in response to one or a combination of sensing signals from a group of sensing signals indicative of operating status of said combustion engine including at least an oil temperature and a coolant temperature.

5. The dosing apparatus of claim 2, wherein said purge controller is further configured to drive said pump at a predetermined pumping rate and energize said injector open when operating said control valve open.

6. The dosing apparatus of claim 1, further comprising:

a nozzle fluidly connected to said control valve for limiting a flow rate of said reductant flow passing through said second high pressure port of said Venturi T connector.

7. The dosing apparatus of claim 1, further comprising

a nozzle fluidly connected to said buffer chamber for releasing reductant therein when a pressure is established in said buffer chamber.

8. The dosing apparatus of claim 1, further comprising

a pressure relief valve fluidly coupled to said buffer chamber, wherein reductant in said buffer chamber is released when a pressure in said buffer chamber is higher than a predetermined value.

9. The dosing apparatus of claim 8, further comprising:

a bypass check valve fluidly connected in parallel to said pressure relief valve to provide a path for a reverting reductant flow going into said buffer chamber.

10. The dosing apparatus of claim 8, further comprising:

a nozzle fluidly connected to said pressure relief valve for limiting a reductant low passing therethrough.

11. The dosing apparatus of claim 1, further comprising:

a pressure sensor for providing a sensing value indicative of a reductant pressure in said buffer chamber; and

a pressure controller configured to control reductant pressure in said buffer according to at least said sensing value obtained from said pressure sensor.

12. The dosing apparatus of claim 11, further comprising:

a purge controller configured to drive said pump at a predetermined pumping rate and energize said injector open when operating said control valve open, and de-energize said pump and said injector and operate said valve closed after a period of time since the moment when said sensing value obtained from said pressure sensor indicates said reductant pressure is below a predetermined value.

13. A dosing apparatus delivering reductant to an exhaust gas treatment system of an internal combustion engine, comprising

a Venturi T connector with a first high pressure port, a second high pressure port, and a low pressure port, at which a low pressure is created when a fluid flows through said first high pressure port and said second high pressure port;

a reductant return passage fluidly connected to said first high pressure port of said Venturi T connector;

a reductant storage chamber fluidly connected to said second high pressure port of said Venturi T connector;

a reductant supply chamber fluidly connected to said low pressure port of said Venturi T connector; and

a pump fluidly coupled to said reductant supply chamber for drawing reductant therefrom.

14. The dosing apparatus of claim 13, further comprising:

a control valve fluidly coupled to said reductant return passage for controlling a reductant flow passing therethrough.

15. The dosing apparatus of claim 14, further comprising:

a purge controller configured to operate said control valve open and drive said pump at a predetermined pumping rate after a dosing process completes.