# US 10,865,680 B2 · Exhaust gas purifying device of work machine

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

- Number: US 10,865,680 B2
- Document ID: US10865680B2
- Status: Granted
- Kind: B2
- Application number: 15/774,312
- Filed: 2016-10-28
- Published: 2020-08-13
- Granted: 2020-12-15
- Earliest claimed: 2015-11-09
- Assignees: Hitachi Construction Machinery Co., Ltd.
- Applicants: Hitachi Construction Machinery Co., Ltd.
- Inventors: Gen Yasuda; Takenori Hiroki; Ryou Takaichi; Hisashi Tago; Hironori Itou
- Web page: https://patentgrep.com/patent/US10865680B2

## CPC

- F01N 3/00: Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust (electric control F01N9/00; monitoring or diagnostic devices for exhaust-gas treatment apparatus F01N11/00)
- F01N 3/2066: {Selective catalytic reduction [SCR]}
- F01N 3/208: {Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent}
- F01N 3/08: for rendering innocuous (using electric or electrostatic separators F01N3/01; chemical aspects B01D53/92)
- F01N 3/18: characterised by methods of operation; Control
- F01N 11/00: Monitoring or diagnostic devices for exhaust-gas treatment apparatus
- F01N 2550/05: Systems for adding substances into exhaust
- F01N 2610/02: the substance being ammonia or urea
- F01N 2610/1433: Pumps
- F01N 2610/146: Control thereof, e.g. control of injectors or injection valves
- F01N 2610/148: Arrangement of sensors
- F01N 2900/1808: Pressure
- F01N 2900/1818: Concentration of the reducing agent
- Y02T 10/12: Improving ICE efficiencies
- Y02T 10/40: Engine management systems
- 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)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A reduction in measurement accuracy of a concentration sensor is minimized. An exhaust gas purifying device of a work machine includes a reduction catalyst that is placed in an exhaust flow passage of an exhaust gas of an engine and uses a reducing agent to reduce and purify nitrogen oxides in the exhaust gas, and a reducing agent injector to inject the reducing agent into the exhaust flow passage. The exhaust gas purifying device of a work machine includes: a storage unit that stores the reducing agent; a concentration sensor that has a sensing part placed within the storage unit to detect a concentration of the reducing agent; an air-bubble removal device that injects the reducing agent toward the sensing part; and a reducing agent pump that supplies the reducing agent in the storage unit to the air-bubble removal device.

## Claims

### Claim 1

An exhaust gas purifying device of a work machine, including a reduction catalyst that is placed in an exhaust flow passage of an exhaust gas of an engine and uses a reducing agent to reduce and purify nitrogen oxides in the exhaust gas, and a reducing agent injector to inject the reducing agent into the exhaust flow passage, the exhaust gas purifying device of the work machine comprising:
a urea water tank that stores the reducing agent;
a concentration sensor that has a sensing part placed within the urea water tank to detect a concentration of the reducing agent;
an injection valve that injects the reducing agent toward the sensing part;
a reducing agent pump that supplies the reducing agent in the urea water tank to the injection valve;
a pressure sensor that detects a discharge pressure of the reducing agent pump; and
an air-bubble removal controller that controls, based on a value detected by the concentration sensor and a value detected by the pressure sensor, injection of the reducing agent performed by the injection valve.

### Claim 2 (depends on 1)

The exhaust gas purifying device of a work machine according to claim 1, wherein the air-bubble removal controller causes the injection valve to start injecting the reducing agent, when the value detected by the concentration sensor is a value representing that at least the reducing agent is in a low concentration state.

### Claim 3 (depends on 1)

The exhaust gas purifying device of a work machine according to claim 1, wherein a second flow passage through which the reducing agent discharged from the reducing agent pump is supplied to the injection valve is connected to a first flow passage that connects a discharge side of the reducing agent pump and the reducing agent injector.