Exhaust purification system

• US 10,450,921 B2
• Filed: 03/23/2017
• Issued: 10/22/2019
• Est. Priority Date: 03/28/2016
• Status: Active Grant

• Current Assignee: Isuzu Motors Limited
• Original Assignee: Isuzu Motors Limited
• Inventors: Osada, Katsushi, Imai, Takehito
• Primary Examiner(s): Duong, Tom P
• Application Number:
  US16/090,136
• Publication Number:
  US 20190120110A1
• Time in Patent Office: 943 Days
• Field of Search: 422176, 422177
• CPC Class Codes: B01D 53/94 by catalytic processes
• CPC Class Codes: B01D 53/9431 Processes characterised by a specific device
• CPC Class Codes: B01F 23/2132 using nozzles
• CPC Class Codes: B01F 25/3141 with additional mixing means other than injector mixers
• CPC Class Codes: B01F 25/4231 using baffles
• CPC Class Codes: F01N 2240/20 a flow director or deflector
• CPC Class Codes: F01N 2610/02 the substance being ammonia or urea
• CPC Class Codes: F01N 2610/1453 Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
• CPC Class Codes: F01N 3/2073 with means for generating a reducing substance from the exhaust gases
• CPC Class Codes: F01N 3/208 Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
• CPC Class Codes: F01N 3/2892 Exhaust flow directors or the like, e.g. upstream of catalytic device
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

An exhaust purification system is equipped with: a linear exhaust pipe through which exhaust gas emitted from an engine passes; an injection nozzle that injects a reducing agent into the exhaust pipe at an oblique angle with respect to the axial direction of the pipe; a reduction catalyst that is provided in the exhaust system downstream from the injection nozzle, and that purifies the exhaust gas by causing the exhaust gas to react with the reducing agent; and a mixer member that is provided inside the exhaust pipe 13, downstream from the injection nozzle, and that causes the reducing agent to mix with the exhaust gas and diffuse. The mixer member includes multiple fins protruding downstream, and is arranged inclined inside the exhaust pipe such that the upstream surface thereof faces the injection opening surface of the injection nozzle.

Claims

1. An exhaust purification system comprising:

an exhaust pipe, which has a straight line shape, and through which exhaust gas discharged from an engine flows;

an injection nozzle configured to inject a reducing agent into the exhaust pipe in a direction obliquely with respect to a pipe axial direction;

a reduction catalyst provided in an exhaust system that is on a downstream side of the injection nozzle and configured to purify the exhaust gas by reacting the exhaust gas with the reducing agent; and

a mixer member provided inside the exhaust pipe on the downstream side of the injection nozzle and on an upstream side of the reduction catalyst and configured to mix and diffuse the reducing agent with the exhaust gas,

wherein the mixer member comprises a plurality of fins protruding to the downstream side, and wherein the mixer member is arranged inside the exhaust pipe in an inclined manner such that an upstream side surface of the mixer member, which is on an opposite side of the fins, faces an injection port surface of the injection nozzle,

wherein the linear piping is formed in a cylindrical shape, and

wherein the mixer member comprises;

a ring member having an elliptic annular shape, an outer periphery of the ring member being fixed to an inner periphery of the linear piping;

a plurality of plate members arranged inside the ring member in a grid shape; and

the plurality of the fins that is integrally formed with the plurality of plate members and is bent at a predetermined angle.

2. The exhaust purification system according to claim 1, wherein the mixer member is arranged inside the exhaust pipe in an inclined manner such that the upstream side surface is perpendicular to an injection axial direction of the injection nozzle.

3. The exhaust purification system according to claim 1,

wherein the injection nozzle is configured to inject urea water into the linear piping, and

wherein the reduction catalyst is a selective reduction catalyst that takes ammonia generated from the urea water by hydrolysis with exhaust heat as a reducing agent and reduces and purifies nitrogen compounds contained in the exhaust gas.

4. The exhaust purification system according to claim 1,

wherein the linear piping is formed in a cylindrical shape, and

wherein the mixer member comprises:

a ring member having an elliptic annular shape, an outer periphery of the ring member being fixed to an inner periphery of the linear piping;

a hub of plate members arranged at a center of the ring member; and

the plurality of the fins radially provided around the hub.