# US 6,295,809 B1 · Emission control system with a catalyst

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

- Number: US 6,295,809 B1
- Document ID: US6295809B1
- Status: Granted
- Kind: B1
- Application number: 09/353,294
- Filed: 1999-07-12
- Granted: 2001-10-02
- Earliest claimed: 1999-07-12
- Assignees: Ford Global Technologies, LLC
- Inventors: Robert Henry Hammerle; Karen Marie Adams; Paul Matthew Laing
- Web page: https://patentgrep.com/patent/US6295809B1

## CPC

- F01N 3/208: {Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent}
- B01D 53/9431: {Processes characterised by a specific device}
- B01D 53/9495: {Controlling the catalytic process}
- F01N 3/206: {Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents}
- F01N 2560/021: for measuring or detecting ammonia NH3
- F01N 2560/06: the means being a temperature sensor
- F01N 2610/02: the substance being ammonia or urea
- F01N 2610/146: Control thereof, e.g. control of injectors or injection valves
- F01N 2900/08: said parameters being related to the engine
- 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)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A reductant injection control strategy for controlling an amount of nitrogen oxide reducing agent injected upstream of a selective reduction catalyst uses an ammonia sensor located downstream of the catalyst. An open loop injection quantity is first determined based on operation conditions. Ammonia concentration detected downstream of the catalyst is controlled to a desired value, with the desired value based on catalyst temperature and the open loop injection quantity.

## Claims

### Claim 1

A method for controlling a reductant injection into a catalyst coupled to an internal combustion engine, the method comprising:
determining a temperature region in which the catalyst is operating;
generating a reductant injection quantity based on engine operating conditions;
generating a desired reductant slip based on a catalyst temperature and said reductant injection quantity; and
adjusting said reductant injection quantity so that an actual reductant slip approaches said desired reductant slip, wherein adjusting said reductant injection quantity further comprises determining said actual reductant slip based on a sensor located downstream of the catalyst, and decreasing said reductant infection quantity when said actual reductant slip is greater than said desired reductant slip.

### Claim 2 (depends on 3)

The method recited in claim 3 wherein the reductant is any ammonia generating material.

### Claim 3 (depends on 3)

The method recited in claim 3 wherein said step of generating said desired value of reductant slip further comprises generating said desired value of reductant slip based on a fraction of said reductant injection quantity.

### Claim 4 (depends on 3)

The method recited in claim 3 further comprising the step of generating said desired value of reductant slip based on Nox generated by the engine.

### Claim 5 (depends on 3)

The method recited in claim 3 wherein said fraction is based on said catalyst temperature.

### Claim 6 (depends on 3)

The method recited in claim 3 wherein said step of generating said reductant injection quantity further comprises the step of generating said reductant injection quantity based on a catalyst temperature and a fraction of an engine out nitrogen oxide production.

### Claim 7 (depends on 3)

The method recited in claim 3 further comprising the step of discontinuing said adjustment step based on whether said catalyst temperature is within temperature limits.

### Claim 8 (depends on 7)

The method recited in claim 7 wherein said step temperature limits are based on exhaust gas space velocity.