# US 9,517,436 B2 · Exhaust purification system of internal combustion engine

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,517,436 B2
- Document ID: US9517436B2
- Status: Granted
- Kind: B2
- Application number: 14/130,414
- Filed: 2012-09-10
- Published: 2015-08-13
- Granted: 2016-12-13
- Earliest claimed: 2012-09-10
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Yuki Bisaiji; Kohei Yoshida; Mikio Inoue; Kohki Nakamura
- Inventors: Yuki Bisaiji; Kohei Yoshida; Mikio Inoue; Kohki Nakamura
- Web page: https://patentgrep.com/patent/US9517436B2

## CPC

- B01D 53/9431: {Processes characterised by a specific device}
- F01N 3/021: by means of filters
- F01N 3/0253: {adding fuel to exhaust gases}
- F01N 3/0814: {combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts}
- F01N 3/0842: {Nitrogen oxides}
- F01N 3/0871: {using means for controlling, e.g. purging, the absorbents or adsorbents}
- F01N 3/2066: {Selective catalytic reduction [SCR]}
- F01N 2610/03: the substance being hydrocarbons, e.g. engine fuel
- F01N 2610/144: Control thereof
- F01N 2610/1453: Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
- F01N 2900/1808: Pressure
- 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)
- 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)

## Abstract

An internal combustion engine wherein an exhaust purification catalyst and hydrocarbon feed valve are arranged in an engine exhaust passage and wherein the NOX which is contained in the exhaust gas is removed by injection of hydrocarbons from the hydrocarbon feed valve by a predetermined period. Hydrocarbons are injected from the hydrocarbon feed valve toward the upstream side of the engine exhaust passage. When hydrocarbons are injected from the hydrocarbon feed valve by a predetermined period, the injection pressure of the hydrocarbons is made to gradually fall from injection start to injection end in the injection time period of each injection.

## Claims

### Claim 1

An exhaust purification system of an internal combustion engine comprising:
an exhaust purification catalyst arranged in an engine exhaust passage, exhaust gas flow surfaces of the exhaust purification catalyst carrying precious metal catalysts thereon, basic exhaust gas flow surface parts formed around the precious metal catalysts, the exhaust purification catalyst having a property of reducing NOx which is contained in an exhaust gas when a concentration of hydrocarbons which flow into the exhaust purification catalyst is made to vibrate within a predetermined range of amplitude and within a predetermined range of period, the exhaust purification catalyst having a property of increasing a storage amount of NOx contained in the exhaust gas when the vibration period of the hydrocarbon concentration is made longer than the predetermined range of period;
a hydrocarbon feed valve arranged in the engine exhaust passage upstream of the exhaust purification catalyst, the hydrocarbon feed valve being oriented to inject the hydrocarbons in an upstream direction of the engine exhaust passage; and
an electronic control unit coupled to the hydrocarbon feed valve and configured to control injection of the hydrocarbons by the hydrocarbon feed valve so that, at a time of engine operation, the hydrocarbons are injected from the hydrocarbon feed valve within the predetermined range of period to thereby remove the NOx which is contained in the exhaust gas while gradually reducing an injection pressure of the hydrocarbons from a start of the injection toward an end of the injection during each injection period, the injection pressure of the hydrocarbons at the start of the injection and the injection pressure of the hydrocarbons at the end of the injection being set so that the hydrocarbons which are injected later are superposed in the engine exhaust passage with the hydrocarbons that were previously injected.

### Claim 2 (depends on 1)

The exhaust purification system as claimed in claim 1, further comprising a sensor that measures a flow amount of the exhaust gas, and wherein the electronic control unit is configured to increase a pressure difference between the injection pressure of the hydrocarbons at the start of the injection and the injection pressure of the hydrocarbons at the end of the injection as the measured flow amount increases.

### Claim 3 (depends on 1)

The exhaust purification system as claimed in claim 1, further comprising a sensor that measures a temperature of the exhaust gas, and wherein the electronic control unit is configured to increase a pressure difference between the injection pressure of the hydrocarbons at the start of the injection and the injection pressure of the hydrocarbons at the end of the injection as the measured temperature increases.

### Claim 4 (depends on 1)

The exhaust purification system as claimed in claim 1, further comprising a particulate filter arranged in the engine exhaust passage, and wherein the electronic control unit is configured to control the hydrocarbon feed valve so that when the hydrocarbons are injected from the hydrocarbon feed valve to raise a temperature of the particulate filter, the injection pressure of the hydrocarbons at the start of the injection is made lower than when the hydrocarbons are injected from the hydrocarbon feed valve within the predetermined range of period.

### Claim 5 (depends on 1)

The exhaust purification system as claimed in claim 1, wherein the electronic control unit is configured to control the hydrocarbon feed valve so that the injection pressure of the hydrocarbons is made lower at the start of the injection when the hydrocarbons are injected from the hydrocarbon feed valve so as to raise a temperature of the exhaust purification catalyst compared to the injection pressure of the hydrocarbons when the hydrocarbons are injected within the predetermined period.