System for Controlling Urea Injection Quantity of Vehicle and Method Thereof

• US 20100031639A1
• Filed: 01/21/2009
• Published: 02/11/2010
• Est. Priority Date: 08/07/2008
• Status: Active Grant

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group), Kia Motors Corporation (Kia Corp.)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group), Kia Motors Corporation (Kia Corp.)
• Inventors: KWON, Soon Hyung
• Granted Patent: US 8,181,448 B2
• Time in Patent Office: Days
• US Class Current: 60/286
• CPC Class Codes: F01N 2240/20 a flow director or deflector
• CPC Class Codes: F01N 2560/026 for measuring or detecting NOx
• CPC Class Codes: F01N 2560/06 the means being a temperature sensor
• CPC Class Codes: F01N 2560/08 the means being a pressure sensor
• CPC Class Codes: F01N 2560/14 having more than one sensor of one kind
• CPC Class Codes: F01N 3/208 Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A system for controlling urea injection quantity of a vehicle, may include an SCR device, the SCR device purifying NOx, a pump configured to supply the SCR device with a urea solution of a urea tank through a urea supply line, a dosing injector disposed on the exhaust pipe at upstream side of the SCR device and injecting the urea solution, and a control portion that closes the dosing injector not to exhaust the urea solution that is charged in the urea supply line if operation of the engine is stopped and outside temperature is higher than a predetermined base temperature, and that stops the pump and opens the dosing injector to exhaust the urea solution charged in the urea supply line to the urea tank if operation of the engine is stopped and the outside temperature is equal to or lower than the predetermined base temperature.

Claims

1. A system for controlling urea injection quantity of a vehicle, comprising:

an SCR (selective catalytic reduction) device connected to an exhaust pipe of an engine, the SCR device purifying NOx included in exhaust gas of the engine by using a reduction reaction between NH3 and the NOx;

a pump configured to supply the SCR device with a urea solution of a urea tank through a urea supply line;

a dosing injector disposed on the exhaust pipe at upstream side of the SCR device and injecting the urea solution to the exhaust pipe, wherein the urea supply line connects the pump and the dosing injector; and

a control portion that closes the dosing injector not to exhaust the urea solution that is charged in the urea supply line in case that operation of the engine is stopped and outside temperature is higher than a predetermined base temperature, and that stops the pump and opens the dosing injector to exhaust the urea solution charged in the urea supply line to the urea tank in case that operation of the engine is stopped and the outside temperature is equal to or lower than the predetermined base temperature.

2. The system for controlling urea injection quantity of a vehicle of claim 1, a pressure sensor is disposed on the urea supply line and signals a current pressure of the urea solution therein to the control portion.

3. The system for controlling urea injection quantity of a vehicle of claim 1, the dosing injector is disposed higher than the urea supply line so as to exhaust the urea solution charged in the urea supply line by gravity to the urea tank when the dosing injector is opened.

4. The system for controlling urea injection quantity of a vehicle of claim 1, wherein the predetermined base temperature is set to be equal to or higher than freezing point of the urea solution that is charged in the urea supply line.

5. The system for controlling urea injection quantity of a vehicle of claim 4, wherein the predetermined base temperature is set to at least one temperature value ranging from approximately 0°

C. to approximately −

5°

C.

6. The system for controlling urea injection quantity of a vehicle of claim 1, wherein, if the outside temperature is higher than the predetermined base temperature, the dosing injector is closed not to inject the urea solution in a condition in which an ignition key is in an ignition-on state for restarting the engine.

7. The system for controlling urea injection quantity of a vehicle of claim 1, wherein the control portion opens the dosing injector for a predetermined time period so as to exhaust the urea solution in the urea supply line if the engine stops operating and the outside temperature is equal to or lower than the predetermined base temperature.

8. The system for controlling urea injection quantity of a vehicle of claim 1, wherein the control portion opens the dosing injector until line pressure in the urea supply line becomes equal to or lower than a predetermined line pressure so as to exhaust the urea solution in the urea supply line if the engine stops operating and the outside temperature is equal to or lower than the predetermined base temperature.

9. The system for controlling urea injection quantity of a vehicle of claim 1, wherein the control portion controlling the dosing injector by PWM signals makes control duty of the dosing injector be 0% so as to close the dosing injector if the engine stops operating and the outside temperature is higher than the predetermined base temperature.

10. The system for controlling urea injection quantity of a vehicle of claim 1, wherein the control portion controlling the dosing injector by PWM signals makes control duty of the dosing injector be 0% so as to close the dosing injector if the engine stops operating, the ignition-on state of an ignition key is detected before restarting the engine, and the outside temperature is higher than the predetermined base temperature.

11. The system for controlling urea injection quantity of a vehicle of claim 1, wherein the control portion controlling the dosing injector by PWM signals makes control duty of the dosing injector be 0% so as to open the dosing injector for a predetermined time period if the engine stops operating and the outside temperature is equal to or lower than the predetermined base temperature.

12. The system for controlling urea injection quantity of a vehicle of claim 1, wherein the control portion controlling the dosing injector by PWM signals makes control duty of the dosing injector be 0% so as to open the dosing injector until line pressure in the urea supply line becomes equal to or lower than a predetermined line pressure if the engine stops operating and the outside temperature is equal to or lower than the predetermined base temperature.

13. A passenger vehicle comprising the system for controlling urea injection quantity of a vehicle of claim 1.

14. A method for controlling urea injection quantity of a vehicle, comprising:

a) comparing an outside temperature with a predetermined base temperature when an engine stops operating;

b) sustaining a pressure of a urea solution that is charged in a urea supply line by closing a dosing injector when the outside temperature is higher than the predetermined base temperature; and

c) storing a final control data of the dosing injector and applying the final control data when an ignition key for the engine is on an ignition on state to be restarted.

15. The method for controlling urea injection quantity of a vehicle of claim 14, further comprising:

after step a), closing the dosing injector until the engine operates, when the ignition key is in an ignition-on state for restarting the engine, after the engine stops operating in a condition in which the outside temperature is higher than the predetermined base temperature.

16. The method for controlling urea injection quantity of a vehicle of claim 14, further comprising:

opening the dosing injector for a predetermined time period so as to exhaust the urea solution in the urea supply line if the engine stops operating and the outside temperature is equal to or lower than the predetermined base temperature.

17. The method for controlling urea injection quantity of a vehicle of claim 14, further comprising:

opening the dosing injector until line pressure in the urea supply line becomes equal to or lower than a predetermined line pressure so as to exhaust the urea solution in the urea supply line to if when the engine stops operating and the outside temperature is equal to or lower than the predetermined base temperature.

18. The method for controlling urea injection quantity of a vehicle of claim 14, wherein the predetermined base temperature is set to be equal to or higher than freezing point of the urea solution that is charged in the urea supply line.

19. The method for controlling urea injection quantity of a vehicle of claim 18, wherein the predetermined base temperature is set to at least one temperature value ranging from approximately 0°

C. to approximately −

5°

C.