Calibration strategies to improve spinel mixed metal oxides catalytic converters

• US 9,951,706 B2
• Filed: 04/21/2015
• Issued: 04/24/2018
• Est. Priority Date: 04/21/2015
• Status: Active Grant

• Current Assignee: Clean Diesel Technologies, Inc.
• Original Assignee: Clean Diesel Technologies, Inc.
• Inventors: Launois, Maxime, Nazarpoor, Zahra, Golden, Stephen J.
• Primary Examiner(s): LATHERS, KEVIN ANTHONY
• Application Number:
  US14/692,577
• Publication Number:
  US 20160312730A1
• Time in Patent Office: 1,099 Days
• CPC Class Codes: F01N 2510/0684 having more than one coating layer, e.g. multi-layered coatings
• CPC Class Codes: F01N 3/28 Construction of catalytic reactors
• CPC Class Codes: F02D 2250/36 Control for minimising NOx emissions
• CPC Class Codes: F02D 41/08 for idling F02D41/06, F02D41/16 take precedence
• CPC Class Codes: F02D 41/1441 Plural sensors
• CPC Class Codes: F02D 41/1446 the characteristics being exhaust temperatures
• CPC Class Codes: F02D 41/1456 with sensor output signal being linear or quasi-linear with the concentration of oxygen
• CPC Class Codes: F02D 41/1475 Regulating the air fuel ratio at a value other than stoichiometry
• CPC Class Codes: F02D 41/2432 Methods of calibration
• CPC Class Codes: F02D 41/2461 by learning a value and then controlling another value
• CPC Class Codes: G01M 15/104 using oxygen or lambda-sensors testing catalytic converters F01N3/18, F01N11/007

Abstract

Modified calibration strategies for controlling an internal combustion engine and monitoring catalyst performance are disclosed. The modified calibration strategies are implemented using an engine and test cell/catalyst chamber setup wherein the engine is a Euro V 1.2 L turbo gasoline direct injection engine and test cells/catalyst chamber are implemented as substantially free of platinum group metals (PGM) catalysts, herein referred as ZPGM catalysts, and synergized PGM (SPGM) catalysts including a stoichiometric spinel structure within the catalyst configuration. The utilization of an open ECU enables the modified calibration of the engine out targeted AFR. The conventional ECU AFR control strategies are not modified to have the ECU AFR control strategies to continue running normally and only the final engine out targeted AFR values are modified by applying offset AFR values. The modified calibration strategies improve engine operation and catalyst conversion efficiency of the ZPGM and SPGM catalysts including the spinel structures.

Claims

1. A method for optimizing the air to fuel ratio (AFR) of an engine using a transient drive cycle testing protocol, the method comprising:

providing from a combustion engine an exhaust flow exposed to a catalyst, wherein the catalyst comprises;

a substrate,

a washcoat layer deposited overlying the substrate, the washcoat layer comprising a support oxide, and

an overcoat layer deposited overlying the washcoat, the overcoat layer comprising a spinel having the general formula;

A_xB_3-xO₄,

where A and B are selected from the group consisting of Fe, Ni, Mn, Co, Cu, Al, Sr, and Zr, and x is a number from 0.1 to 2;

testing the exhaust flow using a transient drive cycle testing protocol model comprising a plurality of urban driving cycle (UDC) phases having at least two idle phases;

providing at least one target AFR value during each UDC phase;

determining at least one modified AFR value during each UDC phase, wherein the at least one modified AFR value varies from the at least one target AFR; and

adjusting one of the at least one target AFR value to correspond to one of the at least one modified AFR value during at least one of the at least two idle phases;

wherein the at least one modified AFR value is indicative of at least one of a more lean or a more rich condition.

2. The method of claim 1, wherein the more lean condition is determined at an R-value of 0.02 from about zero seconds to 300 seconds, and in accordance with a NEDC testing protocol.

3. The method of claim 1, wherein the more rich condition is determined at an R-value of +0.02 from about 300 seconds to 1,180 seconds, and in accordance with a NEDC testing protocol.

4. The method of claim 1, wherein the conversion rate of NOx present in the exhaust stream is improved by said adjusting ones of the at least one target AFR value to correspond to ones of the at least one modified AFR value during at least one of the at least two idle phases.

5. The method of claim 4, wherein the conversion rate of NOx is improved by at least 30%.

6. The method of claim 4, wherein the conversion rate of NOx is improved by at least 90%.

7. The method of claim 1, wherein the transient drive cycle testing protocol is selected from the group consisting of the New European Driving Cycle testing protocol, the World Harmonized Transient Cycle protocol, the EPA Federal Test Procedure, and the Japanese JC08 cycle protocol.

8. The method of claim 1, wherein the transient drive cycle testing protocol comprises at least four UDC phases.

9. The method of claim 1, wherein the transient drive cycle testing protocol comprises at least one extra-urban driving cycle.

10. The method of claim 1, wherein the plurality of UDC phases are substantially equal in duration.

11. The method of claim 1, wherein at least one of the plurality of UDC phases has a duration of greater than 200 seconds.

12. The method of claim 1, wherein the plurality of UDC phases have a total duration of less than 900 seconds.

13. The method of claim 1, wherein the catalyst comprises a ZPGM catalyst or a synergized PGM catalyst.

14. The method of claim 1, wherein the support oxide is selected from the group consisting of Al₂O₃, MgAl₂O₄, Al₂O₃—

BaO, Al₂O₃—

La₂O₃, ZrO₂—

CeO₂—

Nd₂O₃—

Y₂O₃, CeO₂—

ZrO₂, CeO₂, SiO₂, alumina silicate, ZrO₂—

Y₂O₃—

SiO₂, Al₂O₃—

CeO₂, Al₂O₃—

SrO, TiO₂-10% ZrO₂, TiO₂-10% Nb₂O₅, SnO₂—

TiO₂, ZrO₂—

SnO₂—

TiO₂, BaZrO₃, BaTiO₃, BaCeO₃, ZrO₂—

Pr₆O₁₁, ZrO₂—

Y₂O₃, ZrO₂—

Nb₂O₅, Al—

Zr—

Nb, and Al—

Zr—

La.

15. The method of claim 1, wherein the catalyst is free of a platinum based metal.

16. The method of claim 1, wherein the overcoat layer consists of CuMn₂O₄ supported on a Nb-doped zirconia support oxide.

17. The method of claim 16, further comprising a second overcoat layer overlying the impregnation layer, the second overcoat layer comprising a platinum group metal.

18. The method of claim 1, wherein the catalyst further comprises an impregnation layer overlying the overcoat layer, the impregnation layer comprising a Cu—

Mn spinel.

19. The method of claim 18, wherein the platinum group metal is present in a loading amount that is from about 1 g/ft³ to about 10 g/ft³, based on the total volume of the second overcoat layer, and wherein the second overcoat layer includes alumina as a support.

20. The method of claim 18, wherein the second overcoat layer comprises a platinum and rhodium.