Coordinated control of engine and after treatment systems

Patent metadata

Field	Value
Publication number	US-9605613-B2
Application number	US-201414276495-A
Country	US
Kind code	B2
Filing date	May 13, 2014
Priority date	May 13, 2014
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

The present disclosure relates to a method and apparatus to reduce fuel consumption while remaining in NOx compliance by simultaneous and coordinated control of the engine and the selective catalytic reduction (SCR) system. More particularly, the present disclosure identifies methods and apparatus to increase NOx output within a diesel engine to optimize the performance of a given SCR system while simultaneously reducing fuel consumption at a selected and targeted intake oxygen concentration.

First claim

The invention claimed is:

1. A method for controlling a selective catalytic reduction (SCR) system of an internal combustion engine and intake oxygen concentration comprising:
identifying for a selected engine the relationship between fuel consumption and NOx output as a function of intake oxygen concentration (f 1 ), wherein said selected engine includes a SCR system containing a SCR catalyst;
determining for the SCR system associated with said selected engine the current amount of reductant stored in said SCR catalyst and the reductant storage capacity of said SCR catalyst, wherein

a
=

Amount
⁢

⁢
of
⁢

⁢
Reductant
⁢

⁢
Stored
⁢

⁢
in
⁢

⁢
SCR
⁢

⁢
Catalyst

Reductant
⁢

⁢
Storage
⁢

⁢
Capacity
⁢

⁢
of
⁢

⁢
SCR
⁢

⁢
Catalyst

determining a targeted level of NOx output for said engine (NOx*), wherein said value of NOx* is achieved by increasing the value of a by increasing the amount of reductant stored on said SCR catalyst;
selecting a targeted intake oxygen concentration (f 1 *) for the selected engine to achieve said value of NOx*; and
operating said engine at said value of f 1 * and adjusting said engine fuel consumption for said value of f 1 *.

2. The method of claim 1 wherein said value of NOx* is achieved by adjustment of one or more of the following engine operating parameters:
(a) temperature of the SCR catalyst (T SCR )
(b) engine speed (N E )
(c) torque load (T E ).

3. The method of claim 1 wherein said value of f 1 * is achieved by adjustment of one or more of the following engine operating parameters:
(a) engine speed (N E )
(b) intake manifold pressure (T IM )
(c) coolant temperature (T W )
(d) torque load (T E ).

4. The method of claim 1 wherein said value of f 1 * is achieved by an engine air handling controller which adjusts one or more of the following:
(a) engine intake oxygen concentration (f 1 );
(b) the pressure of oxygen in the intake (p 1 );
(c) the pressure of oxygen in the exhaust (p 3 );
(d) the oxygen concentration in the exhaust (f 3 ).

5. The method of claim 1 wherein said fuel consumption of said engine is adjusted by a fueling controller which adjusts the level of fuel introduced to said engine when said engine operates at said target intake oxygen concentration (f 1 *).

6. A method for controlling a selective catalytic reduction (SCR) system of an internal combustion engine and intake oxygen concentration comprising:
identifying for a selected engine the relationship between fuel consumption and NOx output as a function of intake oxygen concentration (f 1 ), wherein said selected engine includes a SCR system containing a SCR catalyst;
determining for the SCR system associated with said selected engine a current amount of reductant stored in said SCR catalyst and the reductant storage capacity of said SCR catalyst, wherein

a
=

Amount
⁢

⁢
of
⁢

⁢
Reductant
⁢

⁢
Stored
⁢

⁢
in
⁢

⁢
SCR
⁢

⁢
Catalyst

Reductant
⁢

⁢
Storage
⁢

⁢
Capacity
⁢

⁢
of
⁢

⁢
SCR
⁢

⁢
Catalyst

identifying a first targeted value for a identified as (a* 1 );
identifying a second and relatively lower targeted value for a as (a* E );
modulating the injected amount of reductant to increase the value of a towards (a* 1 ); and
modulating the production of NOx by controlling the intake oxygen concentration to drive the value of a towards (a* E ).

7. The method of claim 6 wherein said first targeted value (a* 1 ) and said second and relatively lower targeted value (a* E ) are selected such that there is no NOx slip and/or reductant slip.

8. A control device for a selective catalytic reduction (SCR) system of an internal combustion engine and intake oxygen concentration, the control device configured to:
identify for a selected engine the relationship between fuel consumption and NOx output as a function of intake oxygen concentration (f 1 ), wherein said selected engine includes a SCR system containing a SCR catalyst;
determine for the SCR system associated with said selected engine a current amount of reductant stored in said SCR catalyst and the reductant storage capacity of said SCR catalyst, wherein

a
=

Amount
⁢

⁢
of
⁢

⁢
Reductant

Assignees

• Southwest Res Inst

Inventors

• Sarlashkar Jayant V
• Roecker Ryan C

Classifications

• F02D41/0002

  Controlling intake air · CPC title

• F01N2900/1622

  Catalyst reducing agent absorption capacity or consumption amount · CPC title

• Y02T10/42

  Cross-Sectional Technologies · mapped topic

• F02D41/0235 Primary

  in relation with the state of the exhaust gas treating apparatus (control of exhaust gas treating apparatus per se F01N) · CPC title

• F01N3/208

  Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent · CPC title