# US 8,465,702 B2 · Exhaust purification system of internal combustion engine

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- Number: US 8,465,702 B2
- Document ID: US8465702B2
- Status: Granted
- Kind: B2
- Application number: 13/581,766
- Filed: 2010-05-12
- Published: 2013-02-28
- Granted: 2013-06-18
- Earliest claimed: 2010-05-12
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Yoshihisa Tsukamoto; Hiromasa Nishioka; Katsuhiko Oshikawa; Hiroshi Otsuki; Junichi Matsuo
- Inventors: Yoshihisa Tsukamoto; Hiromasa Nishioka; Katsuhiko Oshikawa; Hiroshi Otsuki; Junichi Matsuo
- Web page: https://patentgrep.com/patent/US8465702B2

## CPC

- B01D 53/9418: {for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas}
- B01D 53/925: {Simultaneous elimination of carbon monoxide or hydrocarbons and nitrogen oxides}
- B01D 53/9495: {Controlling the catalytic process}
- B01J 23/66: Silver or gold
- B01J 37/0242: {Coating followed by impregnation}
- F01N 3/0814: {combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts}
- F01N 3/0871: {using means for controlling, e.g. purging, the absorbents or adsorbents}
- F01N 3/101: {Three-way catalysts}
- F01N 3/208: {Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent}
- F01N 13/009: {having two or more separate purifying devices arranged in series}
- F01N 13/0097: {the purifying devices are arranged in a single housing}
- F01N 13/16: Selection of particular materials
- B01D 53/9477: {with catalysts positioned on separate bricks, e.g. exhaust systems}
- B01D 2251/2067: Urea
- B01D 2251/208: Hydrocarbons
- B01D 2255/1021: Platinum
- B01D 2255/1025: Rhodium
- B01D 2255/104: Silver
- B01D 2255/2063: Lanthanum
- B01D 2255/2092: Aluminium
- B01D 2255/91: NOx-storage component incorporated in the catalyst
- B01D 2258/012: Diesel engines and lean burn gasoline engines
- B01J 23/50: Silver
- F01N 3/0842: {Nitrogen oxides}
- F01N 2430/085: at least a part of the injection taking place during expansion or exhaust stroke
- F01N 2510/0684: having more than one coating layer, e.g. multi-layered coatings
- F01N 2570/14: Nitrogen oxides
- F01N 2610/02: the substance being ammonia or urea
- F01N 2610/03: the substance being hydrocarbons, e.g. engine fuel
- F01N 2610/146: Control thereof, e.g. control of injectors or injection valves
- F01N 2900/0601: being estimated
- F01N 2900/1602: Temperature of exhaust gas apparatus
- F01N 2900/1614: NOx amount trapped in catalyst
- F01N 2900/1622: Catalyst reducing agent absorption capacity or consumption amount
- Y02A 50/20: Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
- Y02T 10/12: Improving ICE efficiencies
- 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)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- 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)
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

In an exhaust purification system of an internal combustion engine of the present invention, a silver-alumina-based catalyst device and NOX reducing catalyst device are arranged in the engine exhaust system. When a temperature of the silver-alumina-based catalyst device becomes a first set temperature T1 on the high temperature side, NOX released from the silver-alumina-based catalyst device is reduced by reducing material to be purified in the NOX reducing catalyst device. When the temperature of the silver-alumina-based catalyst device becomes a second set temperature on the low temperature side, NOX released from the silver-alumina-based catalyst device is reduced by reducing material to be purified in the NOX reducing catalyst device.

## Claims

### Claim 1

An exhaust purification system of an internal combustion engine in which the engine exhaust system, a silver-alumina-based catalyst device and NOX reducing catalyst device are arranged, wherein when a temperature of said silver-alumina-based catalyst device becomes a first set temperature on the high temperature side, NOX released from said silver-alumina-based catalyst device is reduced by reducing material to be purified in said NOX reducing catalyst device and when the temperature of said silver-alumina-based catalyst device becomes a second set temperature on the low temperature side, NOX released from said silver-alumina-based catalyst device is reduced by reducing material to be purified in said NOX reducing catalyst device.

### Claim 2 (depends on 1)

An exhaust purification system of an internal combustion engine according to claim 1, wherein an amount of adsorbed NOX on the high temperature side adsorbed in said silver-alumina-based catalyst device when the temperature of said silver-alumina-based catalyst devices is equal to or higher than said second set temperature and is lower than said first set temperature is estimated.

### Claim 3 (depends on 2)

An exhaust purification system of an internal combustion engine according to claim 2, wherein only when the estimated amount of adsorbed NOX on the high temperature side is a first set amount or over, the NOX released from said silver-alumina-based catalyst device is reduced by the reducing material to be purified in said NOX reducing catalyst device when the temperature of said silver-alumina-based catalyst device becomes said first set temperature.

### Claim 4 (depends on 3)

An exhaust purification system of an internal combustion engine according to claim 3, wherein when the temperature of said silver-alumina-based catalyst device becomes said first set temperature and the NOX released from said silver-alumina-based catalyst device is reduced to be purified in said NOX reducing catalyst device, an amount of reducing material supplied to said NOX reducing catalyst device is determined on the basis of the estimated amount of adsorbed NOX on the high temperature side.

### Claim 5 (depends on 2)

An exhaust purification system of an internal combustion engine according to claim 2, wherein when the temperature of said silver-alumina-based catalyst device becomes said first set temperature and the NOX released from said silver-alumina-based catalyst device is reduced to be purified in said NOX reducing catalyst device, an amount of reducing material supplied to said NOX reducing catalyst device is determined on the basis of the estimated amount of adsorbed NOX on the high temperature side.

### Claim 6 (depends on 1)

An exhaust purification system of an internal combustion engine according to claim 1, wherein an amount of adsorbed NOX on the low temperature side adsorbed in said silver-alumina-based catalyst device when the temperature of said silver-alumina-based catalyst devices is lower than said second set temperature is estimated.

### Claim 7 (depends on 6)

An exhaust purification system of an internal combustion engine according to claim 6, wherein only when the estimated amount of adsorbed NOX on the low temperature side is a second set amount or over, the NOX released from said silver-alumina-based catalyst device is reduced by the reducing material to be purified in said NOX reducing catalyst device when the temperature of said silver-alumina-based catalyst device becomes said second set temperature.

### Claim 8 (depends on 7)

An exhaust purification system of an internal combustion engine according to claim 7, wherein when the temperature of said silver-alumina-based catalyst device becomes said second set temperature and the NOX released from said silver-alumina-based catalyst device is reduced to be purified in said NOX reducing catalyst device, an amount of reducing material supplied to said NOX reducing catalyst device is determined on the basis of the estimated amount of adsorbed NOX on the low temperature side.

### Claim 9 (depends on 6)

An exhaust purification system of an internal combustion engine according to claim 6, wherein when the temperature of said silver-alumina-based catalyst device becomes said second set temperature and the NOX released from said silver-alumina-based catalyst device is reduced to be purified in said NOX reducing catalyst device, an amount of reducing material supplied to said NOX reducing catalyst device is determined on the basis of the estimated amount of adsorbed NOX on the low temperature side.