Generation and delivery of ammonia gas in an exhaust gas system

Patent metadata

Field	Value
Publication number	US-9687782-B1
Application number	US-201615014562-A
Country	US
Kind code	B1
Filing date	Feb 3, 2016
Priority date	Feb 3, 2016
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

An exhaust gas system for an engine producing an exhaust gas includes an exhaust gas tube configured to receive the exhaust gas. A particulate filter is in fluid communication with the exhaust gas tube and configured to undergo thermal regeneration when the exhaust gas in the particulate filter is heated above a regeneration temperature. A generator unit is positioned downstream of the particulate filter and includes a first catalyst. A tank is configured to store a precursor material. The generator unit is configured to employ the precursor material and the heat generated for the thermal regeneration of the particulate filter to generate an ammonia gas from the precursor material. The system includes a controller having a processor and tangible, non-transitory memory on which is recorded instructions for executing a method of controlling generation of ammonia gas in the generator unit and injection of ammonia gas in the exhaust gas tube.

First claim

The invention claimed is:

1. An exhaust gas system for treating an exhaust gas, the system comprising:
an exhaust gas tube configured to receive the exhaust gas;
a particulate filter in fluid communication with the exhaust gas tube and configured to undergo thermal regeneration when the exhaust gas in the particulate filter is heated above a regeneration temperature, thereby generating heat;
a generator unit positioned downstream of the particulate filter and including a first catalyst;
a tank operatively connected to the generator unit and configured to store a precursor material;
a first flow control device positioned between the tank and the generator unit, the first flow control device being configured to control flow of the precursor material from the tank to the generator unit;
wherein the generator unit is configured to employ the precursor material and the heat generated due to the thermal regeneration of the particulate filter to generate an ammonia gas.

2. The exhaust gas system of claim 1 , further comprising:
a controller including a processor and tangible, non-transitory memory on which is recorded instructions for executing a method of controlling generation of the ammonia gas in the generator unit and delivery of the ammonia gas to the exhaust gas tube, execution of the instructions by the processor causing the controller to:
determine if the thermal regeneration is taking place; and
if the thermal regeneration is taking place, direct the first flow control device to at least partially permit the precursor material to flow from the tank to the generator unit.

3. The exhaust gas system of claim 2 , further comprising:
a heat exchange unit having a first pathway configured for flow of a first fluid and a second pathway configured for flow of a second fluid, the heat exchange unit being operatively connected to the particulate filter;
wherein the first pathway and the second pathway are separate such that the first and second fluids do not physically mix; and
wherein the first pathway and the second pathway are separated by at least one wall such that the heat generated for the thermal regeneration is transferred from the first fluid to the second fluid through the at least one wall.

4. The exhaust gas system of claim 3 , further comprising:
a second flow control device operatively connected to the controller and positioned between the particulate filter and the heat exchange unit;
wherein the controller is programmed to direct the second flow control device to at least partially permit the exhaust gas to flow from the particulate filter to the first pathway of the heat exchange unit during the thermal regeneration of the particulate filter.

5. The exhaust gas system of claim 3 :
wherein the generator unit and the heat exchange unit share a common housing such that the first catalyst of the generator unit is installed in the second pathway of the heat exchange unit; and
wherein the controller is programmed to direct the first flow control device to at least partially permit the flow of the precursor material from the tank to the second pathway of the heat exchange unit during the thermal regeneration of the particulate filter.

6. The exhaust gas system of claim 2 , further comprising:
a storage unit operatively connected to the generator unit and including a storage material configured to adsorb the ammonia gas;
a third flow control device operatively connected to the controller and positioned between the generator unit and the storage unit;
wherein the controller is programmed to direct the third flow control device to at least partially permit the flow of the ammonia gas from the generator unit to the storage unit during the thermal regeneration of the particulate filter.

7. The exhaust gas system of claim 6 , further comprising:
a heat source operatively connected to the controller, wherein the controller is programmed to direct the heat source to selectively provide a heat energy to the storage unit for releasing the ammonia gas adsorbed by the storage material;
a fourth flow control device operatively connected to the controller and positioned between the storage unit and the exhaust gas tube;
wherein the controller is programmed to direct the fourth flow control device to at least partially permit the flow of the ammonia gas from the storage unit to the exhaust gas tube, irrespective of whether the thermal regeneration of the particulate filter is taking place.

8. The exhaust gas system of claim 6 , further comprising:
a selective catalytic reduction device in fluid communication with the exhaust gas tube and including a second catalyst; and
wherein the ammonia gas is configured to interact with the second catalyst in the selective catalytic reduction device to reduce a NOx level in the exhaust gas.

9. A vehicle comprising:
an engine;
an exhaust gas tube in fluid communication with and configured to receive an exhaust gas from the engine;
a particulate filter in fluid communication with the exhaust gas tube and configured to undergo thermal regeneration when the exhaust gas in the particulate filter is heated above a regeneration temperature;
a generator unit positioned downstream of the particulate filter and including a first catalyst;
a tank operatively connected to the generator unit and configured to store a precursor material;
a first flow control device positioned between the tank and the generator unit, the first flow control device being configured to control flow of the precursor material from the tank to the generator unit;
wherein the generator unit is configured to employ the precursor material and the heat generated due to the thermal regeneration of the particulate filter to produce an ammonia gas; and
a controller including a processor and tangible, non-transitory memory on which is recorded instructions for executing a method of controlling generation of the ammonia gas in the generator unit and delivery of the ammonia gas to the exhaust gas tube, execution of the instructions by the processor causing the controller to direct the first flow control device to at least partially permit the precursor material to flow from the tank to the generator unit if the thermal regeneration is taking place.

10. The vehicle of claim 9 , further comprising:
a heat exchange unit having a first pathway configured for flow of a first fluid and a second pathway configured for flow of a second fluid, the heat exchange unit being operatively connected to the particulate filter;
wherein the first pathway and the second pathway are separate such that the first and second fluids do not physically mix; and
wherein the first pathway and the second pathway are separated by at least one wall such that the heat generated for the thermal regeneration is transferred from the first fluid to the second fluid through the at least one wall.

11. The vehicle of claim 10 , further comprising:
a second flow control device operatively connected to the controller and positioned between the particulate filter and the heat exchange unit; and
wherein the controller is programmed to direct the second flow control device to at least partially permit the exhaust gas to flow from the particulate filter to the first pathway of the heat exchange unit during the thermal regeneration of the particulate filter.

12. The vehicle of claim 11 :
wherein the generator unit and the heat exchange unit share a common housing such that the first catalyst of the generator unit is installed in the second pathway of the heat exchange unit; and
wherein the controller is programmed to direct the first flow control device to at least partially permit the f

Assignees

• Gm Global Tech Operations Llc

Inventors

• Miao Yong

Classifications

• F01N3/027

  using electric or magnetic heating means · CPC title

• F01N2240/25

  an ammonia generator · CPC title

• F01N9/00

  Electrical control of exhaust gas treating apparatus (monitoring or diagnostic devices for exhaust-gas treatment apparatus F01N11/00; conjoint electrical control of two or more combustion engine functions F02D43/00) · CPC title

• B01D2251/2067

  Urea · CPC title

• F01N2610/02

  the substance being ammonia or urea · CPC title