# US 8,783,022 B2 · Retrofit aftertreatment system for treating diesel exhaust

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- Number: US 8,783,022 B2
- Document ID: US8783022B2
- Status: Granted
- Kind: B2
- Application number: 12/846,419
- Filed: 2010-07-29
- Published: 2011-03-03
- Granted: 2014-07-22
- Earliest claimed: 2009-08-17
- Assignees: Donaldson Company, Inc.
- Applicants: Henry Joseph Drasner, III; Andrew Alan Gilb; Paul Anthony Way
- Inventors: Henry Joseph Drasner, III; Andrew Alan Gilb; Paul Anthony Way
- Web page: https://patentgrep.com/patent/US8783022B2

## CPC

- F01N 3/035: with catalytic reactors
- F01N 3/0231: {using special exhaust apparatus upstream of the filter for producing nitrogen dioxide, e.g. for continuous filter regeneration systems [CRT]}
- F01N 3/103: {Oxidation catalysts for HC and CO only}
- F01N 3/208: {Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent}
- F01N 9/002: {of filter regeneration}
- F01N 13/009: {having two or more separate purifying devices arranged in series}
- F01N 13/0093: {the purifying devices are of the same type}
- F01N 13/0097: {the purifying devices are arranged in a single housing}
- F01N 2510/06: for exhaust purification, e.g. catalytic reaction
- F01N 2510/0682: having a discontinuous, uneven or partially overlapping coating of catalytic material, e.g. higher amount of material upstream than downstream or vice versa
- F01N 2560/026: for measuring or detecting NOx
- F01N 2560/06: the means being a temperature sensor
- F01N 2560/08: the means being a pressure sensor
- F01N 2560/14: having more than one sensor of one kind
- F01N 2610/02: the substance being ammonia or urea
- 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

An exhaust aftertreatment system for diesel engines includes a filtration station, a NOx reduction station, a temperature sensor, a pressure data generator, a NOx sensor, a reductant dispenser, and a controller. The filtration station filters particulate material from the exhaust. The NOx reduction station reduces NOx concentration in the exhaust. The temperature sensor generates first data that is representative of a temperature of the exhaust. The pressure data generator generates second data that is indicative of a pressure differential across a control volume that is located at the NOx reduction station. The control volume includes at least one catalyzed substrate. The NOx sensor generates third data that is representative of the NOx concentration in the exhaust. The reductant dispenser dispenses reductant into the exhaust. The controller controls a dosing rate of the reductant dispenser. The controller uses the first, second, and third data to determine the dosing rate.

## Claims

### Claim 1

An exhaust aftertreatment system for treating exhaust generated by a diesel engine, the system comprising:
a filtration station for filtering particulate material from the exhaust;
a substrate located downstream from the filtration station;
a pressure data generator for generating data indicative of a pressure differential across a constant flow area control volume of the exhaust aftertreatment system, the constant flow area control volume including the substrate;
a reactant dispenser for dispensing reactant into the exhaust; and
a controller that controls a dosing rate at which the reactant dispenser dispenses the reactant into the exhaust, wherein the controller uses the data indicative of the pressure differential across the constant flow area control volume as a parameter for determining the dosing rate at which the reactant dispenser dispenses the reactant into the exhaust, and wherein the controller determines an exhaust flow rate based on a correlation of the data from the pressure data generator with the constant flow area control volume.

### Claim 2 (depends on 1)

The system of claim 1, wherein the substrate has a pass-through configuration.

### Claim 3 (depends on 1)

The system of claim 1, wherein the substrate is an SCR substrate.

### Claim 4 (depends on 1)

The system of claim 1, wherein the dosing rate is directly dependent upon a magnitude of the pressure differential across the constant flow area control volume.

### Claim 5 (depends on 1)

The system of claim 1, further comprising a NOx sensor for generating data representative of a concentration of NOx in the exhaust and a temperature sensor for generating data representative of a temperature of the exhaust, wherein the controller uses the data from the NOx sensor and the data from the temperature sensor as parameters for determining the dosing rate at which the reactant dispenser dispenses the reactant into the exhaust.

### Claim 6 (depends on 5)

The system of claim 5, wherein the NOx sensor is positioned between the filtration station and the reactant dispenser.

### Claim 7 (depends on 6)

The system of claim 6, wherein the temperature sensor is positioned between the reactant dispenser and a NOx reduction station.

### Claim 8 (depends on 7)

The system of claim 7, wherein an exhaust mixer is positioned between the temperature sensor and the reactant dispenser.

### Claim 9 (depends on 8)

The system of claim 8, wherein the filtration station includes a pre-filter positioned upstream from a wall flow filter.

### Claim 10 (depends on 9)

The system of claim 9, wherein the NOx reduction station includes two SCR substrates positioned in series.

### Claim 11 (depends on 10)

The system of claim 10, wherein the pressure data generator includes a pressure differential sensor having a first sensing location positioned upstream from the two SCR substrates and a second sensing location positioned downstream from the two SCR substrates.

### Claim 12

An exhaust aftertreatment system for treating exhaust generated by a diesel engine, the system comprising:
a filtration station for filtering particulate material from the exhaust;
a NOx reduction station located downstream from the filtration station for reducing a concentration of NOx in the exhaust;
a temperature sensor for generating first data representative of a temperature of the exhaust;
a pressure data generator for generating second data indicative of a pressure differential across a control volume located at the NOx reduction station, the control volume including at least one catalyzed substrate;
a NOx sensor for generating third data representative of the concentration of the NOx in the exhaust;
a reductant dispenser for dispensing reductant into the exhaust at a location between the filtration station and the NOx reduction station; and
a controller that controls a dosing rate at which the reductant dispenser dispenses the reductant into the exhaust, wherein the controller uses the first data, the second data and the third data to determine the dosing rate at which the reductant dispenser dispenses the reductant into the exhaust, and wherein the controller determines an exhaust flow rate based on a correlation of the second data from the pressure data generator with the control volume.

### Claim 13 (depends on 12)

The system of claim 12, wherein the substrate has a pass-through configuration.

### Claim 14 (depends on 12)

The system of claim 12, wherein the correlation is a mathematical formula independent of accumulating matter.

### Claim 15 (depends on 12)

The system of claim 12, wherein the correlation assumes a constant flow area.

### Claim 16 (depends on 12)

The system of claim 12, wherein the NOx sensor is positioned between the filtration station and the reductant dispenser.

### Claim 17 (depends on 16)

The system of claim 16, wherein the temperature sensor is positioned between the reductant dispenser and the NOx reduction station.

### Claim 18 (depends on 17)

The system of claim 17, wherein an exhaust mixer is positioned between the temperature sensor and the reductant dispenser.

### Claim 19 (depends on 18)

The system of claim 18, wherein the filtration station includes a pre-filter positioned upstream from a wall flow filter.

### Claim 20 (depends on 19)

The system of claim 19, wherein the NOx reduction station includes two SCR substrates positioned in series.

### Claim 21 (depends on 20)

The system of claim 20, wherein the control volume includes the two SCR substrates.

### Claim 22 (depends on 20)

The system of claim 20, wherein the pressure data generator includes a pressure differential sensor having a first sensing location positioned upstream from the two SCR substrates and a second sensing location positioned downstream from the two SCR substrates.