# US 10,371,032 B2 · Exhaust gas purifier for engine

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

- Number: US 10,371,032 B2
- Document ID: US10371032B2
- Status: Granted
- Kind: B2
- Application number: 15/676,144
- Filed: 2017-08-14
- Published: 2018-03-22
- Granted: 2019-08-06
- Earliest claimed: 2016-09-16
- Assignees: Mazda Motor Corporation
- Applicants: Mazda Motor Corporation
- Inventors: Takashi Kasai; Kazunori Hirasawa; Yoshitaka Wada; Tetsuro Furuta; Masahiro Naito
- Web page: https://patentgrep.com/patent/US10371032B2

## CPC

- F01N 3/2892: {Exhaust flow directors or the like, e.g. upstream of catalytic device}
- F01N 3/2066: {Selective catalytic reduction [SCR]}
- F01N 13/08: Other arrangements or adaptations of exhaust conduits {(pipes, joints or supports therefor in general F16L; collecting or removing exhaust gases of vehicle engines in workshops B08B15/00, on highways E01C1/005)}
- F01N 2240/20: a flow director or deflector
- F01N 2570/14: Nitrogen oxides
- F01N 2610/02: the substance being ammonia or urea
- 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
- 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

An exhaust pipe of an engine includes a crank-shaped pipe portion having a first bend and a second bend which guide exhaust gas to a mixer, and a straight pipe portion which is continuous with the second bend. The mixer is arranged in the straight pipe portion. An injector is attached to a portion of the second bend which faces the mixer. The injector has an injection axis which extends in a longitudinal direction of the straight pipe portion so as to point toward the mixer. A guide which guides a part of the exhaust gas from the first bend toward the injector is provided inside the crank-shaped pipe portion.

## Claims

### Claim 1

An exhaust gas purifier for an engine, the exhaust gas purifier comprising:
an SCR catalyst which is provided in an exhaust pipe of the engine and selectively reduces NOx included in exhaust gas by NH3;
an injector which is provided upstream of the SCR catalyst in the exhaust pipe and injects an aqueous urea solution into the exhaust gas for generating NH3; and
a mixer which is provided between the injector and the SCR catalyst in the exhaust pipe and promotes mixing of the aqueous urea solution injected by the injector and the exhaust gas, wherein
the exhaust pipe includes a crank-shaped pipe portion having a first bend and a second bend which are bent in opposite directions and guide the exhaust gas to the mixer, and a straight pipe portion continuous with the second bend of the crank-shaped pipe portion,
the mixer is arranged in the straight pipe portion,
the injector is attached to a portion of the second bend which faces the mixer, and has an injection axis which extends in a longitudinal direction of the straight pipe portion so as to point toward the mixer,
a guide which guides a part of the exhaust gas from the first bend toward the portion of the second bend to which the injector is attached is provided inside the crank-shaped pipe portion,
the guide has a plate shape and divides an inside of the crank-shaped pipe portion so as to intersect the inside of the crank-shaped pipe portion such that, at a location upstream of the portion to which the injector is attached inside the crank-shaped pipe portion in a flow direction of the exhaust gas, the exhaust gas inside the crank-shaped pipe portion is divided into a flow flowing at a side of the injector and a flow flowing at a side of the mixer, the guide being curved so as to become closer to the portion of the second bend to which the injector is attached in a downstream flow direction of the exhaust gas, and
a groove which is recessed such that a curved portion of the guide has a longer radius of curvature than two side portions of the guide is formed in a width center of the guide which extends in a direction to intersect the inside of the crank-shaped pipe portion.

### Claim 2 (depends on 1)

The exhaust gas purifier of claim 1, wherein
a cone-shaped recess which protrudes in a longitudinal direction of the straight pipe portion and is tapered outward is provided at the portion of the second bend to which the injector is attached, and
the injector has a tip which is attached to a tip of the cone-shaped recess and which points via the cone-shaped recess toward an inside of the second bend.

### Claim 3 (depends on 1)

The exhaust gas purifier of claim 1, wherein
a cone-shaped recess which protrudes in a longitudinal direction of the straight pipe portion and is tapered outward is provided at the portion of the second bend to which the injector is attached, and
the injector has a tip which is attached to a tip of the cone-shaped recess and which points via the cone-shaped recess toward an inside of the second bend.

### Claim 4 (depends on 1)

The exhaust gas purifier of claim 1, wherein
the injector ejects the aqueous urea solution in sprayed form, and
the guide is provided at a location out of a spray angle range of the injector.

### Claim 5 (depends on 1)

The exhaust gas purifier of claim 1, wherein
the guide divides an inside of the crank-shaped pipe portion such that, at an upstream edge of the guide in the flow direction of the exhaust gas, a passage cross-sectional area at the side of the mixer is larger than a passage cross-sectional area at the side of the injector.

### Claim 6 (depends on 5)

The exhaust gas purifier of claim 5, wherein
a cone-shaped recess which protrudes in a longitudinal direction of the straight pipe portion and is tapered outward is provided at the portion of the second bend to which the injector is attached, and
the injector has a tip which is attached to a tip of the cone-shaped recess and which points via the cone-shaped recess toward an inside of the second bend.

### Claim 7

An exhaust gas purifier for an engine, the exhaust gas purifier comprising:
an SCR catalyst which is provided in an exhaust pipe of the engine, and selectively reduces NOx included in exhaust gas by NH3;
an injector which is provided upstream of the SCR catalyst in the exhaust pipe and injects an aqueous urea solution into the exhaust gas for generating NH3; and
a mixer which is provided between the injector and the SCR catalyst in the exhaust pipe and promotes mixing of the aqueous urea solution injected by the injector and the exhaust gas, wherein
the exhaust pipe includes a straight pipe portion in which the mixer is arranged, and an inclined introduction pipe which, in order to introduce the exhaust gas into the mixer, is connected in an inclined manner to the straight pipe portion,
the injector is attached to a portion of the inclined introduction pipe facing the mixer, and has an injection axis which extends in a longitudinal direction of the straight pipe portion so as to point toward the mixer,
a cone-shaped recess which protrudes in the longitudinal direction of the straight pipe portion and is tapered outward is provided at the portion of the inclined introduction pipe facing the mixer,
the injector has a tip which is attached to a tip of the cone-shaped recess and which points via the cone-shaped recess toward an inside of the inclined introduction pipe,
a guide which guides a part of the exhaust gas from the inclined introduction pipe toward the cone-shaped recess is provided inside the inclined introduction pipe,
the guide has a plate shape and divides an inside of the inclined introduction pipe so as to intersect the inside of the inclined introduction pipe such that, at a location upstream of the portion to which the cone-shaped recess is attached inside the inclined introduction pipe in a flow direction of the exhaust gas, the exhaust gas inside the inclined introduction pipe is divided into a flow flowing at a side of the injector and a flow flowing at a side of the mixer, the guide being curved so as to become closer to the cone-shaped recess in a downstream flow direction of the exhaust gas, and
a groove which is recessed such that a curved portion of the guide has a longer radius of curvature than two side portions of the guide is formed in a width center of the guide which extends in a direction to intersect the inside of the inclined introduction pipe.

### Claim 8 (depends on 7)

The exhaust gas purifier of claim 7, wherein
the injector ejects the aqueous urea solution in sprayed form, and
the guide is provided at a location out of a spray angle range of the injector.

### Claim 9

An exhaust gas purifier for an engine, the exhaust gas purifier comprising:
an SCR catalyst which is provided in an exhaust pipe of the engine and selectively reduces NOx included in exhaust gas by NH3;
an injector which is provided upstream of the SCR catalyst in the exhaust pipe and injects an aqueous urea solution into the exhaust gas for generating NH3; and
a mixer which is provided between the injector and the SCR catalyst in the exhaust pipe and promotes mixing of the aqueous urea solution injected by the injector and the exhaust gas, wherein
the exhaust pipe includes a crank-shaped pipe portion having a first bend and a second bend which are bent in opposite directions and guide the exhaust gas to the mixer, and a straight pipe portion continuous with the second bend of the crank-shaped pipe portion,
the mixer is arranged in the straight pipe portion,
the injector is attached to a portion of the second bend which faces the mixer, and has an injection axis which extends in a longitudinal direction of the straight pipe portion so as to point toward the mixer,
a guide which guides a part of the exhaust gas from the first bend toward the portion of the second bend to which the injector is attached is provided inside the crank-shaped pipe portion,
the crank-shaped pipe portion, the straight pipe portion, the SCR catalyst, and the injector are provided inside a floor tunnel which extends in a longitudinal direction of an automobile,
a portion of the crank-shaped pipe portion reaching from the first bend to the second bend extends from one side to an other side of the floor tunnel,
the straight pipe portion which is continuous with the second bend extends backwards in a direction inclined with respect to a longitudinal direction of the floor tunnel from the other side of the floor tunnel toward a width center of the floor tunnel, and
the SCR catalyst extends in a direction corresponding to the longitudinal direction of the floor tunnel.

### Claim 10 (depends on 9)

The exhaust gas purifier of claim 9, wherein
the injection axis of the injector which points toward the mixer and extends in the longitudinal direction of the straight pipe portion does not coincide with a center of the SCR catalyst at an inlet side of the SCR catalyst.