Stoichiometric engine system utilizing three-way catalyst upstream of turbine

Patent metadata

Field	Value
Publication number	US-11261830-B2
Application number	US-201916531463-A
Country	US
Kind code	B2
Filing date	Aug 5, 2019
Priority date	Aug 5, 2019
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

The present disclosure relates to exhaust treatment systems and engine systems. In one implementation, an engine system comprises an engine comprising an intake manifold and an exhaust manifold, the engine configured to combust a fuel-air mixture received via the intake manifold and produce a flow of exhaust gases via the exhaust manifold. The engine system also comprises a turbocharger comprising a turbine, an exhaust passageway fluidly connecting the exhaust manifold of the engine to the turbine and an intake passageway fluidly connected to the intake manifold of the engine for supplying the fuel-air mixture, a catalyzed member positioned along the exhaust passageway between the engine and the turbine, and an exhaust gas recirculation (EGR) loop fluidly connected downstream of the catalyzed member and fluidly connected to the exhaust passageway and the intake passageway.

First claim

What is claimed is:

1. An engine system, comprising:
an engine comprising an intake manifold and an exhaust manifold, the engine configured to combust a fuel-air mixture received via the intake manifold and produce a flow of exhaust gases via the exhaust manifold;
a turbocharger comprising a turbine;
an exhaust passageway fluidly connecting the exhaust manifold of the engine to the turbine and an intake passageway fluidly connected to the intake manifold of the engine for supplying the fuel-air mixture;
a catalyzed member that includes a metal substrate that is adapted to trap particulate matter therein from exhaust gas passing through the exhaust passageway during engine operation, the metal substrate being coated with a three-way catalyst, the catalyzed member positioned along the exhaust passageway between the engine and the turbine;
a control module associated with the engine;
a single exhaust gas sensor disposed along the exhaust passageway, the single exhaust gas sensor positioned between the catalyzed member and the turbine, the single exhaust gas sensor operating to detect constituents of exhaust gas exiting the catalyzed member, the single exhaust gas sensor being communicatively coupled to the control module and operating to provide one or more signals to the control module that are indicative of the detected constituents of exhaust gas exiting the catalyzed member;
an air-fuel regulator disposed along the intake passageway, the air-fuel regulator being communicatively coupled to the control module and operating to control and air-fuel mixture provided to the engine, the air-fuel mixture being provided at an air-fuel ratio (AFR) that is controlled by the air-fuel regulator to be within a desirable range in response to commands provided by the control module, wherein the commands provided by the control module are based on an AFR set point value that is determined by the control module based primarily on the one or more signals provided to the control module from the single exhaust gas sensor; and
an exhaust gas recirculation (EGR) loop fluidly connected downstream of the catalyzed member and fluidly connected to the exhaust passageway and the intake passageway.

2. The engine system of claim 1 , wherein the metal substrate of the catalyzed member comprises a metallic structure coated with the three-way catalyst.

3. The engine system of claim 2 , wherein the metallic structure is a honeycomb structure.

4. The engine system of claim 1 , wherein the turbocharger comprises a compressor fluidly connected between a fluid supply passageway for receiving the fuel-air mixture and the intake passageway and the turbine is fluidly connected between the exhaust passageway and an exhaust outlet passageway to output the exhaust gases, wherein the EGR loop comprises an EGR passageway fluidly connected along the exhaust outlet passageway at an inlet port downstream of the turbine and fluidly connected along the fluid supply passageway at an outlet port upstream of the compressor.

5. The engine system of claim 4 , wherein EGR loop comprises an EGR cooler positioned along the EGR passageway and an EGR valve between the EGR cooler and the outlet port.

6. The engine system of claim 1 , wherein the EGR loop is a low pressure EGR loop.

7. A method for operating an engine comprising:
combusting a fuel-air mixture and producing a flow of exhaust to a turbine of a turbocharger via an exhaust passageway;
directing the flow of exhaust through a catalyzed member prior to providing the flow of exhaust to the turbine, wherein the catalyzed member includes a metal substrate that is adapted to trap particulate matter therein from the flow of exhaust gas, the metal substrate being coated with a three-way catalyst that reduces emissions included in the flow of exhaust; and
controlling an air-to-fuel ratio of the fuel-air mixture primarily based on emissions in the flow of exhaust following the catalyzed member to maintain the air-to-fuel ratio within a predetermined range of a stoichiometric point.

8. The method of claim 7 , wherein the metal substrate of the catalyzed member comprises a metallic structure coated with a three-way catalyst.

9. The method of claim 7 , wherein the catalyzed member reduces hydrocarbons (HC), carbon monoxide (CO), and nitric oxide (NO), and nitric dioxide (NO2) in the exhaust.

10. The method of claim 7 , further comprising
detecting emissions in the flow of exhaust following the catalyzed member;
determining current operating conditions based on the detected emissions; and
determining an air-to-fuel ratio set point based on comparing the current operating conditions against a target operating condition.

11. The method of claim 10 , further comprising adjusting the air-to-fuel ratio of the fuel-air mixture based on the air-to-fuel ratio set point.

12. An exhaust treatment system, comprising:
an exhaust passageway configured to receive a flow of exhaust based on combustion of a fuel-air mixture;
a turbocharger comprising a turbine and a compressor, the turbine configured to receive the flow of exhaust from the exhaust passageway and to induce rotation of the compressor based on the received flow of exhaust;
a catalyzed member that includes a metal substrate that is adapted to trap particulate matter therein from exhaust gas passing through the exhaust passageway during engine operation, the metal substrate being coated with a three-way catalyst, the catalyzed member positioned along the exhaust passageway upstream of the turbine and configured to reduce emissions in the flow of exhaust prior to reception by the turbine; and
a control module comprising a memory storing instruction for operating the exhaust system and a processor coupled to the memory, the processor configured to execute the instructions to control an air-to-fuel ratio of the fuel-air mixture primarily based on emissions in the flow of exhaust following the catalyzed member to maintain the air-to-fuel ratio within a predetermined range of a stoichiometric point.

13. The exhaust treatment system of claim 12 , wherein the metal substrate of the catalyzed member comprises a metallic structure coated with a three-way catalyst.

14. The exhaust treatment system of claim 4 , wherein the catalyzed member reduces hydrocarbons (HC), carbon monoxide (CO), and nitric oxide (NO), and nitric dioxide (NO2) in the exhaust.

15. The exhaust treatment system of claim 12 , further comprising one or more sensors positioned along the exhaust passageway between the catalyzed member and the turbine, the one or more sensors are configured to detect one or more emissions in the flow of exhaust, wherein the control module is further configured to:
determine current operating conditions based on the detected emissions;
determine an air-to-fuel ratio set point based on comparing the current operating conditions against a target operating condition; and
adjust the air-to-fuel ratio of the fuel-air mixture based on the air-to-fuel ratio set point.

Assignees

• Caterpillar Inc

Inventors

• Silver Ronald
• Singh Jaswinder
• Ginter David M
• Wang Paul
• Bardell Michael

Classifications

• F02M2026/009

  EGR combined with means to change air/fuel ratio, ignition timing, charge swirl in the cylinder · CPC title

• F02M26/35 Primary

  with means for cleaning or treating the recirculated gases, e.g. catalysts, condensate traps, particle filters or heaters · CPC title

• F02M26/15

  in relation to engine exhaust purifying apparatus · CPC title

• F02M26/46

  for determining the characteristics of gases, e.g. composition · CPC title

• Y02T10/12

  Improving ICE efficiencies · CPC title