Adaptive reductant dosing and emission control strategies

• US 7,991,533 B2
• Filed: 06/11/2007
• Issued: 08/02/2011
• Est. Priority Date: 06/11/2007
• Status: Active Grant

• Current Assignee: Southwest Research Institute
• Original Assignee: Southwest Research Institute
• Inventors: Huang, Yiqun
• Primary Examiner(s): Gordon; Brian R
• Assistant Examiner(s): Sasaki; Shogo
• Application Number:
  US11/761,205
• Publication Number:
  US 20080306631A1
• Time in Patent Office: 1,513 Days
• Field of Search: 701/101, 701/102, 602/76, 602/95, 731/146.9, 731/147.5, 731/147.7
• US Class Current: 701/101
• CPC Class Codes: B01D 2251/2062 Ammonia
• CPC Class Codes: B01D 2251/2067 Urea
• CPC Class Codes: B01D 2258/012 Diesel engines and lean burn gasoline engines
• CPC Class Codes: B01D 53/9431 Processes characterised by a specific device
• CPC Class Codes: B01D 53/9495 Controlling the catalytic process
• CPC Class Codes: F01N 11/00 Monitoring or diagnostic devices for exhaust-gas treatment apparatus , e.g. for catalytic activity safety, indicating or supervising devices for internal combustion engines F02B77/08; testing of machines G01M13/00
• CPC Class Codes: F01N 2570/14 Nitrogen oxides
• CPC Class Codes: F01N 2610/02 the substance being ammonia or urea
• CPC Class Codes: F01N 2900/0421 using an increment counter when a predetermined event occurs
• CPC Class Codes: F01N 2900/0422 measuring the elapsed time
• CPC Class Codes: F01N 2900/08 said parameters being related to the engine
• CPC Class Codes: F01N 2900/102 Travelling distance
• CPC Class Codes: F01N 2900/1808 Pressure
• CPC Class Codes: F01N 2900/1814 Tank level
• CPC Class Codes: F01N 3/208 Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

The present disclosure relates to a method or apparatus for controlling reductant dosing level introduced to a selective catalytic reduction device. The method or apparatus may determine available reductant and determine a distance to a source of reductant. This may be followed by adjusting a reductant dosing level based upon the available reductant and the distance to the reductant source. The apparatus may be installed in a vehicle and may also regulate in-cylinder emission control variables to reduce NOx emissions.

Claims

1. A method of controlling reductant dosing level introduced to a selective catalytic reduction device implemented by a controller located within a vehicle, comprising:

determining available reductant, based on data received from a sensor in communication with a reductant tank;

determining a distance to a source of reductant, wherein said source of reductant includes a reductant refilling station, based on data received from one or more of the following;

GPS, wireless towers and driver input;

determining if said available reductant is less than a predetermined level;

setting a reductant low limit flag and determining if a by-pass mode has been manually set if said available reductant is less than said predetermined level;

implementing said by-pass mode if said by-pass mode has been manually set, with zero reductant dosing, and counting the number of times said by-pass mode with zero reductant dosing has been previously implemented by said controller;

determining if the number of times previously in said by-pass mode exceeds a previously determined value; and

if said number of times previously in said by-pass mode exceeds a previously determined value operating an engine in said vehicle under an engine calibration for low-engine out emissions.

2. The method of claim 1 further comprising:

adjusting one or more of the following engine parameters when operating said engine under said engine calibration for low-engine out emissions;

fuel injection timing, amount or temperature of exhaust gas recycling, amount or temperature of air flow, fuel mass, compression ratio, variable valve actuation timing, boost pressure or combustion temperature.

3. The method of claim 1 further comprising:

initiating a timer for a given time period after said by-pass mode is implemented; and

further adjusting one or more of the following engine parameters;

injection timing, amount or temperature of exhaust gas recycling, amount or temperature of air flow, fuel mass, compression ratio, variable valve actuation timing, boost pressure or combustion temperature, during said given time period.

4. An article comprising a computer readable storage medium having stored thereon instruction that when executed by a controller included in a vehicle result in the following operations:

determining available reductant, based on data received from a sensor in communication with a reductant tank;

determining a distance to a source of reductant, wherein said source of reductant includes a reductant refilling station, based on data received from one or more of the following;

GPS, wireless towers and driver input;

determining if said available reductant is less than a predetermined level;

setting a reductant low limit flag and determining if a by-pass mode has been manually set if said available reductant is less than said predetermined level;

implementing said by-pass mode if said by-pass mode has been manually set, with zero reductant dosing, and counting the number of times said by-pass mode with zero reductant dosing has been previously implemented by said controller;

determining if the number of times previously in said by-pass mode has exceeded a previously determined value; and

if said number of times previously in said by-pass mode exceeds a previously determined value, operating an engine in said vehicle under an engine calibration for low-engine out emissions.

5. The article of claim 4, wherein said instructions that when executed by said controller result in the following additional operations:

adjusting one or more of the following engine parameters when operating said engine under said engine calibration for low-engine out emissions;

fuel injection timing, amount or temperature of exhaust gas recycling, amount or temperature of air flow, fuel mass, compression ratio, variable valve actuation timing, boost pressure or combustion temperature.

6. The article of claim 4, wherein said instructions that when executed by said controller result in the following additional operations

initiating a timer for a given time period after said by-pass mode is implemented;

and

further adjusting one or more of the following engine parameters;

injection timing, amount or temperature of exhaust gas recycling, amount or temperature of air flow, fuel mass, compression ratio, variable valve actuation timing, boost pressure or combustion temperature, during said given time period.