Urea supply system for a waste gas cleaning catalyst and heating insert suitable therefor

• US 7,836,684 B2
• Filed: 05/22/2006
• Issued: 11/23/2010
• Est. Priority Date: 06/04/2005
• Status: Active Grant

• Current Assignee: Eichenauer Heizelemente GmbH & Co. KG
• Original Assignee: Eichenauer Heizelemente GmbH & Co. KG
• Inventors: Thome, Gerhard, Kexel, Oleg, Lang, Armin, Starck, Roland
• Primary Examiner(s): Denion; Thomas E
• Assistant Examiner(s): Tran; Diem
• Application Number:
  US11/921,363
• Publication Number:
  US 20090100824A1
• Time in Patent Office: 1,646 Days
• Field of Search: 602/86, 602/95, 603/01, 603/03
• US Class Current: 60/286
• CPC Class Codes: B01D 53/9431 Processes characterised by a specific device
• CPC Class Codes: B01D 53/9495 Controlling the catalytic process
• CPC Class Codes: B60K 13/04 concerning exhaust collecting exhaust gases with central suction systems not forming part of vehicles, e.g. in workshops or tunnels B08B15/002, otherwise along carriageways E01C1/005; extensions for melting snow on roads E01H5/00, E01H6/00; exhaust or silencing apparatus for internal combustion engines per se F01N; pipes, joints or supports therefor F16L
• CPC Class Codes: B60K 2015/03427 for heating fuel, e.g. to avoiding freezing
• CPC Class Codes: F01N 13/009 having two or more separate purifying devices arranged in series
• CPC Class Codes: F01N 13/0093 the purifying devices are of the same type
• 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 2610/10 the substance being heated, e.g. by heating tank or supply line of the added substance
• CPC Class Codes: F01N 2610/1406 Storage means for substances, e.g. tanks or reservoirs
• 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 3/2066 Selective catalytic reduction [SCR]
• CPC Class Codes: H05B 3/82 Fixedly-mounted immersion heaters
• 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

The invention relates to a urea supply system for a waste gas cleaning catalyst of an internal combustion engine, comprising a urea tank for the receiving of urea solution, a connecting line that connects the urea tank with a waste gas cleaning catalyst, a pump in order to pump urea solution via the connecting line from the urea tank to the catalyst, and a heating insert for the defrosting of frozen urea solution. According to the invention it is provided that the return line is configured and arranged in such a manner that, during operation, because of the urea solution discharged from the return line there is prevented the forming of an air gap between the heating insert and the frozen urea solution. The invention relates also to a heating insert for such a urea supply system.

Claims

1. A urea supply system for a waste gas cleaning catalyst of an internal combustion engine, comprising:

a urea tank for storing of urea solution;

a connection line that connects the urea tank with a waste gas cleaning catalyst;

a pump to pump urea solution via the connection line from the urea tank to the catalyst;

a heating insert for the defrosting of frozen urea solution, the heating insert comprising at least one PTC-heating element arranged in a metal housing and a plastic casing surrounding the metal housing

a return line that branches off the connection line and extends to the urea tank, said return line being configured and arranged in such a manner that, during operation, the urea solution discharging from the return line prevents forming an air gap between the heating insert and the frozen urea solution to be defrosted; and

a defrosting vessel disposed in the urea tank, the connecting line being connected to the defrosting vessel in which a portion of the frozen urea solution in the system can be defrosted by means of the single heating insert, the portion sufficing for starting of the catalyst, and wherein the return line leads to the defrosting vessel, the defrosting vessel further including an overflow opening through which urea solution can flow from the defrosting vessel into the surrounding urea tank.

2. The urea supply system according to claim 1, further comprising a distribution element is provided at an outlet of the return line to distribute the urea flow discharged from the return line.

3. The urea supply system according to claim 1, wherein the return line is configured and arranged in such a manner that during operation urea is directly conveyed to the heating insert in order to fill a possible gap between the heating insert and frozen urea solution.

4. The urea supply system according to claim 1, wherein the heating insert is provided with an intake pipe that is connected to the connecting line.

5. The urea supply system according to claim 1, wherein the return line has several outlets through which urea is returned during operation.

6. The urea supply system according to claim 1, wherein the return line is provided with a vent hole.