# US 8,783,023 B2 · Exhaust gas purification system for internal combustion engine

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- Number: US 8,783,023 B2
- Document ID: US8783023B2
- Status: Granted
- Kind: B2
- Application number: 13/696,972
- Filed: 2010-05-12
- Published: 2013-03-07
- Granted: 2014-07-22
- Earliest claimed: 2010-05-12
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Shunsuke Toshioka; Shinya Hirota; Kazuhiro Itoh; Koichiro Fukuda; Akira Mikami
- Inventors: Shunsuke Toshioka; Shinya Hirota; Kazuhiro Itoh; Koichiro Fukuda; Akira Mikami
- Web page: https://patentgrep.com/patent/US8783023B2

## CPC

- F01N 3/208: {Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent}
- B01D 53/9495: {Controlling the catalytic process}
- F01N 3/2033: {using a fuel burner or introducing fuel into exhaust duct}
- F01N 13/009: {having two or more separate purifying devices arranged in series}
- B01D 53/90: Injecting reactants
- B01D 53/9409: {Nitrogen oxides}
- B01D 2251/2062: Ammonia
- F01N 2560/06: the means being a temperature sensor
- F01N 2610/02: the substance being ammonia or urea
- F01N 2610/03: the substance being hydrocarbons, e.g. engine fuel
- F01N 2900/0416: using the state of a sensor, e.g. of an exhaust gas sensor
- F01N 2900/1602: Temperature of exhaust gas apparatus
- Y02T 10/12: Improving ICE efficiencies
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

An object of the present invention is to increase the flexibility in the layout of an exhaust gas purification system for an internal combustion engine including selective catalytic reduction catalyst provided in an exhaust passage of the internal combustion engine and an addition device for supplying reducing agent derived from ammonia to the selective catalytic reduction catalyst, without a deterioration of the performance in reducing nitrogen oxides. To achieve the object, the exhaust gas purification system for an internal combustion engine according to the present invention is configured to supply hydrocarbon at the same time when reducing agent derived from ammonia is supplied to the selective catalytic reduction catalyst, thereby producing reducing agent that is hard to be oxidized by a precious metal catalyst.

## Claims

### Claim 1

An exhaust gas purification system for an internal combustion engine, comprising:
a selective catalytic reduction catalyst which is provided in an exhaust passage of the internal combustion engine and which includes a precious metal catalyst;
an addition device which is provided in the exhaust passage upstream of the selective catalytic reduction catalyst and which adds reducing agent derived from ammonia to exhaust gas;
a fuel supply device which supplies fuel to exhaust gas at a location upstream of the selective catalytic reduction catalyst;
a control unit which causes the fuel supply device to supply fuel at the time when reducing agent is added to exhaust gas by the addition device; and
a measuring unit which measures a temperature correlating with the temperature of the selective catalytic reduction catalyst;
wherein the control unit changes the amount of reducing agent added by the addition device and the amount of fuel supplied by the fuel supply device in accordance with the temperature measured by the measuring unit.

### Claim 2 (depends on 1)

An exhaust gas purification system for an internal combustion engine according to claim 1, wherein the control unit controls the addition device and the fuel supply device in such a way as to make the amount of reducing agent smaller and the amount of fuel larger when the temperature measured by the measuring unit is high than when it is low.

### Claim 3 (depends on 1)

An exhaust gas purification system for an internal combustion engine according to claim 1, further comprising a temperature control device which is provided in the exhaust passage upstream of the selective catalytic reduction catalyst and which controls the temperature of exhaust gas.

### Claim 4 (depends on 3)

An exhaust gas purification system for an internal combustion engine according to claim 3, wherein the temperature control device is a burner that burns fuel and secondary air.

### Claim 5 (depends on 2)

An exhaust gas purification system for an internal combustion engine according to claim 2, further comprising a temperature control device which is provided in the exhaust passage upstream of the selective catalytic reduction catalyst and which controls the temperature of exhaust gas.

### Claim 6 (depends on 5)

An exhaust gas purification system for an internal combustion engine according to claim 5, wherein the temperature control device is a burner that burns fuel and secondary air.