EXHAUST SYSTEM

• US 20150267596A1
• Filed: 03/18/2015
• Published: 09/24/2015
• Est. Priority Date: 03/19/2014
• Status: Active Grant

• Current Assignee: Purem GmbH Formerly Eberspacher Exhaust Technology Gesellschaft mbH
• Original Assignee: Eberspacher Exhaust Technology GmbH & Co. KG (Eberspächer Gruppe GmbH & Co. KG)
• Inventors: Tbben, Heike, WIRTH, Georg
• Granted Patent: US 9,464,558 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F01N 13/04 having two or more silencers in parallel, e.g. having interconnections for multi-cylinder engines
• CPC Class Codes: F01N 13/08 Other arrangements or adaptations of exhaust conduits pipes, joints or supports therefor in general F16L; collecting or removing exhaust gases of vehicle engines in workshops B08B15/00, on highways E01C1/005
• CPC Class Codes: F01N 13/14 having thermal insulation exhaust manifolds F01N13/102
• CPC Class Codes: F01N 2240/16 an electric heater, i.e. a resistance heater
• CPC Class Codes: F01N 2610/02 the substance being ammonia or urea
• CPC Class Codes: F01N 2610/03 the substance being hydrocarbons, e.g. engine fuel
• CPC Class Codes: F01N 2610/1453 Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
• CPC Class Codes: F01N 3/0253 adding fuel to exhaust gases
• CPC Class Codes: F01N 3/2066 Selective catalytic reduction [SCR]

Abstract

An exhaust system (1) for an internal combustion engine has an exhaust line (2), which has at least one exhaust pipe (3) having a pipe wall (4) with an inner side (5) defining an exhaust gas path (6) guiding an exhaust gas flow (7) and an electric heating device (18) for heating at least one length section of the exhaust pipe (3). An efficient design is obtained if a heating coil (21) is wound several times around the exhaust pipe (3) on an outer side (22) of the pipe wall (4) in the respective length section and has an electric conductor (23) made of a resistance heating material. An electric insulator (24) is arranged between the conductor (23) and the outer side (22) of the pipe wall (4). A heat-insulating cover (25) envelops the exhaust pipe (3) at least in the area of the respective heating coil (21).

Claims

1. An exhaust system for an internal combustion engine, the exhaust system comprising:

an exhaust line comprising an exhaust pipe with a pipe wall having an inner side defining an exhaust gas path for guiding an exhaust gas flow;

an electric heating device for heating a length section of the exhaust pipe, the the heating device comprising;

a heating coil, which winds several times around the exhaust pipe on an outer side of the pipe wall, in the length section, the heating coil comprising an electric conductor formed of a resistance heating material; and

a heat-insulating cover, which envelops the exhaust pipe at least in the areas of the heating coil; and

an electric insulator arranged between the conductor and the outer side of the pipe wall.

2. An exhaust system in accordance with claim 1, wherein the cover comprises:

a shell mounted on the exhaust pipe; and

an electrically insulating filling, which fills an annular space between the shell and the exhaust pipe, in which the respective heating coil is arranged.

3. An exhaust system in accordance with claim 1, wherein:

the insulator is comprised of an insulating layer applied to the outer side of the pipe wall; and

the conductor is wound on the insulating layer and is in contact with same.

4. An exhaust system in accordance with claim 1, wherein:

the heating coil comprises a core forming the conductor; and

a jacket forms at least part of the insulator and envelops the core.

5. An exhaust system in accordance with claim 1, further comprising an exhaust gas probe mounted on the exhaust pipe, wherein the heating device is arranged in an area of the exhaust gas probe.

6. An exhaust system in accordance with claim 1, further comprising a reactant feed device connected to the exhaust pipe, wherein the heating device is arranged in an area of the reactant feed device.

7. An exhaust system in accordance with claim 6, wherein:

the reactant feed device comprises an injector for introducing reactant into the exhaust gas flow; and

the heating device is arranged in an area of the injector.

8. An exhaust system in accordance with claim 6, wherein:

the reactant feed device comprises an injector for introducing reactant into the exhaust gas flow; and

the heating device is arranged in an areas of a wall section of the exhaust pipe, which wall section is located opposite the injector with respect to a spraying direction of the injector.

9. An exhaust system in accordance with claim 6, wherein:

the reactant feed device comprises an injector for introducing reactant into the exhaust gas flow and a mixer arranged in the exhaust pipe downstream of the injector; and

the heating device is arranged in an area of the mixer.

10. An exhaust system in accordance with claim 9, wherein the mixer comprises a cylindrical pipe body and a plurality of guide blades projecting from the cylindrical pipe body, which is in contact with the inner side of the pipe wall.

11. An exhaust system in accordance with claim 10, wherein in an area of the mixer, the pipe wall has an axial interruption, which is bridged over or filled by the pipe body.

12. An exhaust system in accordance with claim 11, wherein at least one of:

the heating coil is directly in contact with the pipe body in the area of the interruption; and

the heating coil has a higher winding density in an area of the pipe body than outside the area of the pipe body.

13. An exhaust system in accordance with claim 1, wherein at least one of:

the heating device further comprises a control controlling the heating device based on a time diagram and/or characteristic diagram; and

the heating device further comprises a PTC element, which is connected in series with the conductor or which is formed by the conductor; and

the heating device further comprises a regulating device with at least one temperature sensor.

14. An exhaust system in accordance with claim 1, wherein the heating device further comprises a control device configured and/or programmed such that the control device carries out an energization of the heating coil

15. A method for operating an exhaust system for an internal combustion engine, the method comprising the steps of:

providing the exhaust system with an exhaust line comprising an exhaust pipe having a pipe wall with an inner side defining an exhaust gas path for guiding an exhaust gas flow, wherein the exhaust system comprises an electric heating device for heating a length section of the exhaust pipe, which heating device comprises a heating coil wound several times around the exhaust pipe on an outer side of the pipe wall in the length section;

controlling and/or regulating the energization of the respective heating coil such that at least one area in the exhaust pipe, which area is exposed to the risk of condensation of an evaporated liquid being entrained in the exhaust gas flow or to the risk of precipitation of a liquid introduced into the exhaust gas flow, is heated to above an evaporation temperature of the respective liquid.

16. A method in accordance with claim 15, wherein a current exhaust gas temperature and/or a current reactant temperature and/or a current quantity of injected reactant is/are taken into account during the energization of the respective heating coil.