# US 11,028,755 B2 · Rotational exhaust flow control for diesel exhaust fluid injection

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- Number: US 11,028,755 B2
- Document ID: US11028755B2
- Status: Granted
- Kind: B2
- Application number: 16/359,885
- Filed: 2019-03-20
- Published: 2020-09-24
- Granted: 2021-06-08
- Earliest claimed: 2019-03-20
- Assignees: Caterpillar Inc.
- Applicants: Caterpillar Inc.
- Inventors: Kurtis Chenoweth; Jianping Pan; Mohamed Daoud; Srinivasa Perumal Velu; Arvind Jujare; Y. T. Bui
- Web page: https://patentgrep.com/patent/US11028755B2

## CPC

- F01N 3/2066: {Selective catalytic reduction [SCR]}
- F01N 3/2892: {Exhaust flow directors or the like, e.g. upstream of catalytic device}
- B01F 31/10: with a mixing receptacle rotating alternately in opposite directions
- F01N 3/208: {Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent}
- B01F 25/431972: {Mounted on an axial support member, e.g. a rod or bar}
- F01N 2240/20: a flow director or deflector
- F01N 2610/02: the substance being ammonia or urea
- F01N 2610/1453: Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
- 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)
- B01F: MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING (mixing paints B44D3/06)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A selective catalytic reduction (SCR) system is disclosed. The SCR system may include a mixing tube with a mixing tube inlet; a diesel exhaust fluid (DEF) injector proximate to the mixing tube inlet; and a flow control device proximate to the mixing tube inlet, wherein the flow control device is positioned within the mixing tube or affixed to the mixing tube inlet, and wherein the flow control device includes a plurality of vanes arranged around a center of the flow control device.

## Claims

### Claim 1

A selective catalytic reduction (SCR) system, comprising:
a mixing tube with a mixing tube inlet;
a diesel exhaust fluid (DEF) injector proximate to the mixing tube inlet; and
a flow control device proximate to the mixing tube inlet,
wherein the flow control device is positioned within the mixing tube or affixed to the mixing tube inlet,
wherein the flow control device includes a plurality of vanes arranged around a center of the flow control device, and
wherein a depth of a vane, of the plurality of vanes, is configured to provide a radial-to-axial flow ratio in a target range of approximately 1.0 to approximately 2.0.

### Claim 2 (depends on 1)

The SCR system of claim 1, wherein a ratio of the depth of the vane to a diameter of the mixing tube is in a range of approximately 0.06 to approximately 0.1.

### Claim 3 (depends on 1)

The SCR system of claim 1, wherein a number of vanes of the flow control device is configured to provide the radial-to-axial flow ratio in the target range.

### Claim 4 (depends on 3)

The SCR system of claim 3, wherein the number of vanes is in a range of approximately 8 to approximately 12.

### Claim 5 (depends on 1)

The SCR system of claim 1, wherein the plurality of vanes are spaced substantially equally around the center of the flow control device.

### Claim 6 (depends on 1)

The SCR system of claim 1, further comprising:
a chamber upstream from the flow control device and at least partially enclosing the mixing tube.

### Claim 7 (depends on 1)

The SCR system of claim 1, wherein the DEF injector is downstream from the flow control device.

### Claim 8

A diesel exhaust fluid (DEF) system, comprising:
a mixing tube having a mixing tube inlet and a mixing tube outlet,
wherein a mixture of exhaust and DEF is to flow from the mixing tube inlet to the mixing tube outlet;
a DEF injector proximate to the mixing tube inlet; and
a flow control device,
wherein the flow control device includes a plurality of vanes arranged coaxially with the mixing tube,
wherein a depth of a vane, of the plurality of vanes, is configured to provide a radial-to-axial flow ratio in a target range,
wherein a ratio of the depth of the vane to a diameter of the mixing tube is in a range of approximately 0.06 to approximately 0.1, and
wherein the radial-to-axial flow ratio is a particular ratio of radial flow to axial flow for the mixture.

### Claim 9 (depends on 8)

The DEF system of claim 8, wherein the flow control device is provided between the DEF injector and a chamber that at least partially encloses the DEF system.

### Claim 10 (depends on 8)

The DEF system of claim 8, further comprising a mixer assembly proximate to the mixing tube outlet.

### Claim 11 (depends on 8)

The DEF system of claim 8, wherein the particular ratio is approximately 1.4.

### Claim 12 (depends on 8)

The DEF system of claim 8, wherein the flow control device is configured to achieve the particular ratio based on a number of vanes of the plurality of vanes and the ratio of the depth of the vane to the diameter of the mixing tube.

### Claim 13 (depends on 8)

The DEF system of claim 8, wherein a number of vanes of the plurality of vanes is in a range of approximately 8 vanes to approximately 12 vanes.

### Claim 14 (depends on 8)

The DEF system of claim 8, wherein the flow control device is provided upstream from the DEF injector.

### Claim 15

A selective catalytic reduction (SCR) system, comprising:
an exhaust inlet to receive an exhaust flow;
a mixing tube, downstream from the exhaust flow, with a mixing tube inlet;
a diesel exhaust fluid (DEF) injector in the mixing tube to inject DEF for the exhaust flow,
wherein the mixing tube is to mix the DEF with the exhaust flow; and a flow control device proximate to the mixing tube inlet,
wherein the flow control device is positioned within the mixing tube or affixed to the mixing tube inlet,
wherein the flow control device includes a plurality of vanes arranged around a center of the flow control device,
wherein a depth of a vane, of the plurality of vanes, is configured to provide a radial-to-axial flow ratio in a target range, and
wherein as a ratio of the depth of the vane to a diameter of the mixing tube is in a range of approximately 0.06 to approximately 0.1.

### Claim 16 (depends on 15)

The SCR system of claim 15, wherein the flow control device is to reduce the radial-to-axial flow ratio to within the target range.

### Claim 17 (depends on 15)

The SCR system of claim 15,
wherein the plurality of vanes comprises 8 vanes, and
wherein the ratio of the depth of the vane to the diameter of the mixing tube is approximately 0.1.

### Claim 18 (depends on 15)

The SCR system of claim 15,
wherein the plurality of vanes comprises 12 vanes, and
wherein the ratio of the depth of the vane to the diameter of the mixing tube is approximately 0.06.

### Claim 19 (depends on 15)

The SCR system of claim 15, wherein a vane angle is equal between each pair of adjacent vanes of the plurality of vanes.

### Claim 20 (depends on 15)

The SCR system of claim 15, wherein the radial-to-axial flow ratio is a ratio of a radial flow rate of the exhaust flow around a center axis of the mixing tube to an axial flow rate of the exhaust flow along the mixing tube.