Exhaust system for an internal combustion engine and method for operating an exhaust system

Patent metadata

Field	Value
Publication number	US-10502111-B2
Application number	US-201715402601-A
Country	US
Kind code	B2
Filing date	Jan 10, 2017
Priority date	Jan 11, 2016
Publication date	Dec 10, 2019
Grant date	Dec 10, 2019

Abstract

An exhaust system for an internal combustion engine, especially for a vehicle, includes an exhaust gas-carrying pipe (12) and a reactant release unit (14) for releasing reactant (R) into exhaust gas (A) flowing in the exhaust gas-carrying pipe (12). The reactant release unit (14) includes a reactant injection unit (20), a reactant delivery unit (18) delivering reactant (R) from a reactant reservoir to the reactant injection unit (20) and a heating unit (24) for heating reactant (R) being delivered to the reactant injection unit (20). The heating unit (24) includes an exhaust gas/reactant heat exchanger unit (26) for transferring heat, being transported in the exhaust gas (A), to the reactant (R).

First claim

What is claimed is:

1. An exhaust system for an internal combustion engine, the exhaust system comprising:
an exhaust gas-carrying pipe;
a reactant release unit releasing reactant into exhaust gas flowing in the exhaust gas-carrying pipe, the reactant release unit comprising:
a reactant injection unit;
a reactant delivery unit delivering reactant from a reactant reservoir to the reactant injection unit; and
a heating unit provided in a flow path of the reactant between the reactant delivery unit and the reactant injection unit and heating reactant being delivered to the reactant injection unit, the heating unit comprising an exhaust gas/reactant heat exchanger unit transferring heat, being transported in the exhaust gas, to the reactant, the heating unit further comprising an electrically operable heater downstream in relation to the exhaust gas/reactant heat exchanger unit;

an actuating unit configured to actuate the reactant delivery unit, the electrically operable heater and the reactant release unit;
at least one reactant pressure sensor provided in the flow path of the reactant between the exhaust gas/reactant heat exchanger unit and the electrically operable heater, wherein the actuating unit is configured to actuate the reactant delivery unit based on a reactant pressure detected by the reactant pressure sensor;
at least one reactant temperature sensor provided in the flow path of the reactant between the heating unit and the reactant injection unit, wherein the actuating unit is configured to actuate the reactant delivery unit based on a reactant temperature detected by the reactant temperature sensor, wherein the exhaust gas/reactant heat exchanger unit comprises a heat exchanger line area in a reactant line sending reactant to the reactant injection unit, the heat exchanger line area extending, in at least some sections, outside the exhaust gas-carrying pipe and in contact with an outer surface of the exhaust gas-carrying pipe;
insulating material embedding the heat exchange line area, wherein the exhaust gas-carrying pipe is surrounded by the insulating material at least in a length area interacting with the heat exchanger line area.

2. The exhaust system in accordance with claim 1 , wherein the heat exchanger line area extends helically with respect to the exhaust gas-carrying pipe or meanders with respect to the exhaust gas-carrying pipe or both extends helically with respect to the exhaust gas-carrying pipe or meanders with respect to the exhaust gas-carrying pipe.

3. The exhaust system in accordance with claim 1 , wherein the reactant delivery unit is arranged upstream of the heating unit in a direction of flow of the reactant.

4. The exhaust system in accordance with claim 1 , wherein the actuating unit is configured to actuate the electrically operable heating unit or the reactant release unit or any combination of the electrically operable heating unit and the reactant release unit based on the reactant pressure detected by the reactant pressure sensor; or
wherein the actuating unit is configured to actuate the electrically operable heating unit or the reactant release unit or any combination of the electrically operable heating unit and the reactant release unit based on the reactant temperature detected by the reactant temperature sensor.

5. A method for operating an exhaust system, the method comprising the steps of:
providing the exhaust system comprising:
an exhaust gas-carrying pipe;
a reactant release unit releasing reactant into exhaust gas flowing in the exhaust gas-carrying pipe, the reactant release unit comprising:
a reactant injection unit;
a reactant delivery unit delivering reactant from a reactant reservoir to the reactant injection unit; and
a heating unit provided in a flow path of the reactant between the reactant delivery unit and the reactant injection unit and heating reactant being delivered to the reactant injection unit, the heating unit comprising an exhaust gas/reactant heat exchanger unit transferring heat, being transported in the exhaust gas, to the reactant, the heating unit further comprising an electrically operable heater downstream in relation to the exhaust gas/reactant heat exchanger unit;

an actuating unit configured to actuate the reactant delivery unit, the electrically operable heater and the reactant release unit;
at least one reactant pressure sensor provided in the flow path of the reactant between the exhaust gas/reactant heat exchanger unit and the electrically operable heater, wherein the actuating unit is configured to actuate the reactant delivery unit based on a reactant pressure detected by the reactant pressure sensor;
at least one reactant temperature sensor provided in the flow path of the reactant between the heating unit and the reactant injection unit, wherein the actuating unit is configured to actuate the reactant delivery unit based on a reactant temperature detected by the reactant temperature sensor, wherein the exhaust gas/reactant heat exchanger unit comprises a heat exchanger line area in a reactant line sending reactant to the reactant injection unit, the heat exchanger line area extending, in at least some sections, outside the exhaust gas-carrying pipe and in contact with an outer surface of the exhaust gas-carrying pipe;
insulating material embedding the heat exchange line area, wherein the exhaust gas-carrying pipe is surrounded by the insulating material at least in a length area interacting with the heat exchanger line area

delivering reactant from a reactant reservoir to the reactant injection unit; and
heating reactant being delivered to the reactant injection unit by transferring heat, being transported in the exhaust gas, with the heat exchanger unit, to the reactant, wherein the actuating unit actuates the reactant delivery unit such that the reactant pressure is above the vapor pressure of the reactant heated by the heating unit.

6. The method in accordance with claim 5 , wherein the actuating unit actuates the electrically operable heater such that the reactant heated by the heater is brought into a superheated state, such that the reactant temperature is in the range of a desired superheated temperature.

7. An exhaust system for an internal combustion engine, the exhaust system comprising:
an exhaust gas-carrying pipe;
a reactant release unit releasing reactant into exhaust gas flowing in the exhaust gas-carrying pipe, the reactant release unit comprising:
a reactant injection unit;
a reactant delivery unit;
a reactant delivery flow path, wherein the reactant is delivered from a reactant reservoir to the reactant injection unit via the reactant delivery flow path; and
a heating unit provided in the reactant delivery flow path of the reactant between the reactant delivery unit and the reactant injection unit, the heating unit being configured to heat the reactant being delivered to the reactant injection unit, the heating unit comprising an exhaust gas/reactant heat exchanger unit transferring heat, being transported in the exhaust gas, to the reactant, the heating unit further comprising an electrically operable heater downstream of the exhaust gas/reactant heat exchanger unit relative to a flow of the reactant;

an actuating unit configured to actuate the reactant delivery unit, the electrically operable heater and the reactant release unit;
at least one reactant pressure sensor, at least a portion of the reactant delivery flow path being arranged between the exhaust/gas reactant heat exchanger unit and the electrically operable heater, at least a portion of the at least one reactant pressure sensor being arranged in the portion of reactant delivery flow path, wherein the actuating unit is configured to actuate the reactant delivery unit based on a rea

Assignees

• Eberspaecher Exhaust Tech Gmbh

Inventors

• Gaiser Gerd
• Frobenius Fabian
• Weller Bernd

Classifications

• F01N2610/144

  Control thereof · CPC title

• F01N2610/107

  using glow plug heating elements · CPC title

• F01N2610/105

  Control thereof · CPC title

• F01N3/0205

  using heat exchangers · CPC title

• F01N2900/1811

  Temperature · CPC title