Engine systems with exhaust air injection after three-way catalytic converters for non stoichiometric rich operation

Patent metadata

Field	Value
Publication number	US-11519317-B1
Application number	US-202217649840-A
Country	US
Kind code	B1
Filing date	Feb 3, 2022
Priority date	Feb 3, 2022
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

Engine systems use a three-way catalyst followed by air injection and mixing to convert all hydrocarbons and carbon monoxide under various load conditions when exhaust gas temperature is above 500 degrees Celsius. A three-way catalytic converter is disposed in the exhaust system. A nozzle is configured to inject air into the exhaust system downstream from the three-way catalytic converter. A mixing plate with or without catalyst coatings is disposed in the exhaust system downstream from the nozzle. The mixing plate is bow shaped with a concave shaped side facing the nozzle to enhance carbon monoxide conversion. Optional two way catalytic converters are added downstream from the mixing plate to further reduce tailpipe hydrocarbon and carbon monoxide emissions.

First claim

What is claimed is:

1. An engine system comprising:
an engine configured to consume fuel and air to generate an exhaust gas stream;
an exhaust system configured to channel the exhaust gas stream from the engine to a tailpipe for emissions;
a catalytic converter in the exhaust system, configured to convert constituents of the exhaust gas stream;
a nozzle configured to inject air into the exhaust system downstream from the catalytic converter;
a mixing plate disposed in the exhaust system downstream from the nozzle;
sensors disposed in the exhaust system; and
a controller configured to:
receive inputs from the sensors;
compute an air injection rate based on a load on the engine and the inputs; and
command, based on the computed air injection rate, a supply of the air through the nozzle sufficient to convert the constituents remaining after the catalytic converter.

2. The engine system of claim 1 , comprising an oxidation chamber disposed downstream from the catalytic converter, wherein the mixing plate and the nozzle are disposed in the oxidation chamber, the nozzle positioned so that the air is injected through the orifice at the mixing plate to impinge on the mixing plate.

3. The engine system of claim 1 , wherein the mixing plate has a number of holes formed through, and distributed across, the mixing plate, and wherein the mixing plate has an outer perimeter and a series of cutouts around the outer perimeter.

4. The engine system of claim 1 , comprising a substrate chamber disposed downstream from the mixing plate, wherein the substrate chamber contains a substrate configured to channel and mix the exhaust gas stream.

5. The engine system of claim 4 , wherein at least one of the mixing plate and the substrate are coated with a catalyst to enhance carbon monoxide reduction in the exhaust gas stream.

6. The engine system of claim 1 , wherein one of the sensors is disposed between the nozzle and the mixing plate, wherein the controller is configured to correlate the air injection rate to the load on the engine using the inputs from the one of the sensors.

7. The engine system of claim 1 , wherein the catalytic converter comprises a pair of three-way catalytic converters configured to convert hydrocarbons, carbon monoxide and nitrous oxides, and comprising an oxidation chamber disposed downstream from the pair of three-way catalytic converters, wherein the mixing plate is disposed in the oxidation chamber and the exhaust system is configured to discharge the exhaust gas stream directly to atmosphere from the oxidation chamber through the tailpipe.

8. The engine system of claim 1 , comprising an injection system that includes the nozzle and comprising a pump configured to pressurize air from the engine and supply the air to the nozzle.

9. The engine system of claim 8 , wherein the pump comprises a turbocharger of the engine.

10. The engine system of claim 9 , comprising a wastegate of the turbocharger, wherein the wastegate comprises a three-way valve configured to divert boost air to the nozzle.

11. An engine system comprising:
an engine configured to consume fuel and air to generate an exhaust gas stream;
an exhaust system configured to channel the exhaust gas stream from the engine to a tailpipe for emissions;
a first three-way catalytic converter in the exhaust system;
a second three-way catalytic converter in the exhaust system, the first and second three-way catalytic converters configured to convert constituents of the exhaust gas stream;
an air injection system with a nozzle configured to inject air into the exhaust system downstream from the first and second three-way catalytic converters; and
a mixing plate disposed in the exhaust system downstream from the nozzle, the mixing plate bow shaped with a concave shaped side facing the nozzle,
sensors disposed in the exhaust system; and
a controller configured to:
receive inputs from the sensors;
compute an air injection rate based on a load on the engine and the inputs; and

command, based on the computed air injection rate, a supply of the air through the nozzle sufficient to convert the constituents remaining after the second three-way catalytic converter.

12. The engine system of claim 11 , comprising an oxidation chamber disposed downstream from the first and second three-way catalytic converters, wherein the mixing plate and the nozzle are disposed in the oxidation chamber, the nozzle positioned so that the air is injected through the orifice at the mixing plate to impinge on the mixing plate, wherein the oxidation chamber includes an insulated wall to retain heat.

13. The engine system of claim 11 , wherein the mixing plate has a number of holes formed through, and distributed across, the mixing plate, and wherein the mixing plate has an outer perimeter and a series of cutouts around the outer perimeter, wherein the nozzle is formed by a pipe segment extending into the exhaust system, wherein the pipe segment has a nozzle orifice comprising an opening in the pipe segment that opens in a downstream direction toward the mixing plate, wherein the nozzle has an air injector spray angle that simulates the bow shape of the mixing plate to enhance mixing.

14. The engine system of claim 11 , comprising a substrate chamber disposed downstream from the mixing plate, wherein the substrate chamber contains a substrate configured to channel and mix the exhaust gas stream, wherein the substrate is coated with a two-way catalyst configured to convert hydrocarbons and carbon monoxide.

15. The engine system of claim 11 , comprising a pump and a buffer tank receiving and storing air from the pump, wherein the air is injected into the exhaust system from the buffer tank and through the nozzle according to signals received from the controller.

16. The engine system of claim 11 , wherein one of the sensors is disposed between the nozzle and the mixing plate, wherein the controller is configured to correlate the air injection rate to the load on the engine using the inputs from the one of the sensors.

17. The engine system of claim 11 , wherein the engine includes a crankcase connected with the air injection system, wherein crankcase energy from the crankcase is configured to introduce air to the nozzle.

18. The engine system of claim 11 , comprising:
an injection system that includes the nozzle;
a pump in the injection system and configured to pressurize air from the engine and supply the air to the nozzle; and
a heater in the injection system and configured to heat the pressurized air.

19. The engine system of claim 18 , wherein the pump comprises a turbocharger of the engine; and comprising a wastegate of the turbocharger, wherein the wastegate comprises a three-way valve configured to divert boost air to the nozzle.

20. An engine system comprising:
an engine configured to consume a gasoline fuel and air to generate an exhaust gas stream;
an exhaust system configured to channel the exhaust gas stream from the engine to a tailpipe for emission;
a first three-way catalytic converter in the exhaust system;
a second three-way catalytic converter in the exhaust system, the first and second three-way catalytic converters configured to convert constituents of the exhaust gas stream;
an oxidation chamber disposed in the exhaust system downstream from the second three-way catalytic converter;
an air injection system with a nozzle configured to inject air into the exhaust system for mixing with the exhaust gas stream in the oxidation chamber;
a mixing

Assignees

• Gm Global Tech Operations Llc

Inventors

• Liu Chengke
• Hattar Rafat F

Classifications

• F01N2900/08

  said parameters being related to the engine · CPC title

• F01N2240/20

  a flow director or deflector · CPC title

• F01N9/00 Primary

  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

• F01N3/30

  Arrangements for supply of additional air (control, e.g. using by-passes or variable air pump drives, F01N3/22) · CPC title

• F01N3/22

  Control of additional air supply only, e.g. using by-passes or variable air pump drives · CPC title