Optimization method for a lean capable multi-mode engine

• US 6,352,490 B1
• Filed: 02/04/2000
• Issued: 03/05/2002
• Est. Priority Date: 02/04/2000
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Makki, Imad Hassan, Kerns, James Michael, Michelini, John Ottavio
• Primary Examiner(s): Estremsky, Sherry
• Assistant Examiner(s): Lewis, Tisha D.
• Application Number:
  US09/498,141
• Time in Patent Office: 760 Days
• Field of Search: 477/78, 477/110, 477/115, 123/478, 123/333, 123/295, 123/698
• US Class Current: 477/78
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 2050/0025 Transfer function weighting factor
• CPC Class Codes: B60W 2510/0671 Engine manifold pressure
• CPC Class Codes: B60W 2710/0622 Air-fuel ratio
• CPC Class Codes: B60W 30/18 Propelling the vehicle
• CPC Class Codes: B60W 30/1819 Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: F02D 2200/0625 Fuel consumption, e.g. measured in fuel liters per 100 kms or miles per gallon
• CPC Class Codes: F02D 37/02 one of the functions being ignition
• CPC Class Codes: F02D 41/0057 Specific combustion modes combustion modes per se F02D41/3017
• CPC Class Codes: F02D 41/0225 in relation with the gear ratio or shift lever position
• CPC Class Codes: F02D 41/1406 with use of a optimisation method, e.g. iteration
• CPC Class Codes: F02D 41/3029 further comprising a homogeneous charge spark-ignited mode
• CPC Class Codes: F02D 41/3076 with special conditions for selecting a mode of combustion, e.g. for starting, for diagnosing
• CPC Class Codes: F16H 2061/0015 Transmission control for optimising fuel consumptions
• CPC Class Codes: F16H 2061/0087 Adaptive control, e.g. the control parameters adapted by learning
• CPC Class Codes: F16H 61/0213 characterised by the method for generating shift signals
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/84 : Data processing systems or methods, management, administration

Abstract

A method of generating a shift schedule and combustion mode schedule to optimize performance characteristics of a lean capable, multiple combustion mode engine with a time-variant after-treatment system is disclosed. The method comprises the steps of generating a lowest cost value for fuel economy and vehicle emissions as a function of an engine operating mode, wherein the engine operating mode is selected from a group consisting of a homogeneous stoichiometric mode, a homogeneous lean mode, and a stratified mode. The lowest cost value is stored in a shift schedule and combustion mode schedule along with the engine operating parameters that achieved the lowest cost value.

Claims

1. A method of generating a shift schedule and combustion mode schedule for each vehicle speed and wheel torque value associated with a lean capable, multiple combustion mode engine, such that a cost value for fuel consumption and emissions characteristics is optimized, said method comprising the steps of:

(a) generating a lowest cost value as a function of an engine operating mode, wherein said engine operating mode is selected from a group consisting of a homogeneous stoichiometric mode, a homogeneous lean mode, and a stratified mode; and

(b) storing said lowest cost value in said shift schedule and combustion mode schedule.

2. The method of generating a shift schedule and combustion mode schedule according to claim 1, wherein the step of generating a lowest cost value comprises the step of:

(a) generating a lowest homogeneous stoichiometric mode cost value, a lowest homogeneous lean mode cost value, and a lowest stratified mode cost value as a function of an engine operating parameter; and

(b) setting said lowest cost value equal to the lowest of said lowest homogeneous stoichiometric cost value, said lowest homogeneous mode cost value, and said lowest stratified mode cost value.

3. A method according to claim 2, where the method of setting said lowest cost value comprises the step of setting said lowest cost value, where said lowest cost values represent a plurality of engine operating parameter values.

4. A method according to claim 3, wherein the step of representing a plurality of engine operating parameter values comprises the step of representing a plurality of engine operating parameter values, where said plurality of engine operating parameters consists of an EGR value, a spark advance value, a transmission gear value, and an AFR value.

5. A method of generating a shift schedule and combustion mode schedule for each vehicle speed, wheel torque and transmission gear value associated with a lean capable, multiple combustion mode engine, such that a cost value for fuel consumption and emissions characteristics is optimized, said method comprising the steps of:

(a) generating a lowest transmission gear cost value as a function of an engine operating mode, wherein said engine operating mode is selected from a group consisting of a homogeneous stoichiometric mode, a homogeneous lean mode, and a stratified mode; and

(b) storing said lowest transmission gear cost value in said shift schedule and combustion mode schedule.

6. The method of generating a shift schedule and combustion mode schedule according to claim 5, wherein the step of generating a lowest transmission gear cost value comprises the step of:

(a) generating a lowest homogeneous stoichiometric mode cost value, a lowest homogeneous lean mode cost value, and a lowest stratified mode cost value as a function of an engine operating parameter; and

(b) setting said lowest transmission gear cost value equal to the lowest of said lowest homogeneous stoichiometric cost value, said lowest homogeneous mode cost value, and said lowest stratified mode cost value.

7. The method of claim 6, wherein the step of generating said lowest homogeneous stoichiometric mode cost value comprises the step of generating said lowest homogeneous stoichiometric mode cost value as a function of an exhaust gas recirculation value and a spark advance value.

8. The method of claim 7, wherein the step of generating a lowest homogeneous stoichiometric mode cost value as a function of an exhaust gas recirculation value and a spark advance value comprises for each exhaust gas recirculation value and spark advance value:

(a) setting an initial exhaust gas recirculation cost value and an initial spark advance cost value;

(b) determining an evaluation cost value as a function of said exhaust gas recirculation value and said spark advance value;

(c) comparing said evaluation cost value with said spark advance cost value;

(d) setting said spark advance value equal to said evaluation cost value where said evaluation cost value is lower than said spark advance value;

incrementing said spark advance value as a function of said exhaust gas recirculation value; and

repeating steps (b) through (d);

otherwise;

(e) comparing said spark advance cost value with said exhaust gas recirculation cost value;

(f) setting said exhaust gas recirculation cost value equal to said spark advance cost value where said where said spark advance cost value is lower than said exhaust gas recirculation cost value;

incrementing said exhaust gas recirculation value as a function of said homogeneous stoichiometric mode; and

repeating steps (a) through (f);

otherwise;

(g) setting said lowest homogeneous stoichiometric mode cost value equal to said exhaust gas recirculation cost value.

9. The method of claim 6, wherein the step of generating said lowest homogeneous lean mode cost value comprises the step of generating said lowest homogeneous lean mode cost value as a function of an air fuel ratio value, an exhaust gas recirculation value and a spark advance value.

10. The method of claim 9, wherein the step of generating a lowest homogeneous lean mode cost value as a function of an air fuel ratio value, an exhaust gas recirculation value and a spark advance value comprises for each air fuel ratio value, exhaust gas recirculation value and spark advance value:

(a) setting an initial air fuel ratio value, an initial exhaust gas recirculation cost value and an initial spark advance cost value;

(b) determining an evaluation cost value as a function of said air fuel ratio value, said exhaust gas recirculation value and said spark advance value;

(c) comparing said evaluation cost value with said spark advance cost value;

(d) setting said spark advance value equal to said evaluation cost value where said evaluation cost value is lower than said spark advance value;

incrementing said spark advance value as a function of said exhaust gas recirculation value; and

repeating steps (b) through (d);

otherwise;

(e) comparing said spark advance cost value with said exhaust gas recirculation cost value;

(f) setting said exhaust gas recirculation cost value equal to said spark advance cost value where said where said spark advance cost value is lower than said exhaust gas recirculation cost value;

incrementing said exhaust gas recirculation value as a function of said homogeneous lean mode; and

repeating steps (a) through (f);

otherwise;

(g) comparing said exhaust gas recirculating cost value with said air fuel ratio cost value;

(h) setting said air fuel ratio cost value equal to said exhaust gas recirculating cost value where said air fuel ratio cost value is lower than said exhaust gas recirculating cost value;

incrementing said air fuel ratio value as a function of said homogeneous lean mode; and

repeating steps (a) through (h);

otherwise;

(i) setting said lowest homogeneous lean mode cost value equal to said air fuel ratio cost value.

11. The method of claim 6, wherein the step of generating said lowest homogeneous lean mode cost value comprises the step of generating said lowest homogeneous lean mode cost value as a function of a manifold pressure, an exhaust gas recirculation value and a spark advance value.

12. The method of claim 11, wherein the step of generating a lowest homogeneous lean mode cost value as a function of a manifold pressure value, an exhaust gas recirculation value and a spark advance value comprises for each manifold pressure value, exhaust gas recirculation value and spark advance value:

(a) setting an initial manifold pressure value, an initial exhaust gas recirculation cost value and an initial spark advance cost value;

(b) determining an evaluation cost value as a function of said manifold pressure value, said exhaust gas recirculation value and said spark advance value;

(c) comparing said evaluation cost value with said spark advance cost value;

(d) setting said spark advance value equal to said evaluation cost value where said evaluation cost value is lower than said spark advance value;

incrementing said spark advance value as a function of said exhaust gas recirculation value; and

repeating steps (b) through (d);

otherwise;

(e) comparing said spark advance cost value with said exhaust gas recirculation cost value;

(f) setting said exhaust gas recirculation cost value equal to said spark advance cost value where said where said spark advance cost value is lower than said exhaust gas recirculation cost value;

incrementing said exhaust gas recirculation value as a function of said homogeneous lean mode; and

repeating steps (a) through (f);

otherwise;

(g) comparing said exhaust gas recirculating cost value with said manifold pressure cost value;

(h) setting said manifold pressure cost value equal to said exhaust gas recirculating cost value where said manifold pressure cost value is lower than said exhaust gas recirculating cost value;

incrementing said manifold pressure value as a function of said homogeneous lean mode; and

repeating steps (a) through (h);

otherwise;

(i) setting said lowest homogeneous lean mode cost value equal to said air fuel ratio cost value.

13. The method of claim 6, wherein the step of generating said lowest stratified mode cost value comprises the step of generating said lowest stratified mode cost value as a function of an air fuel ratio value, an exhaust gas recirculation value and a spark advance value.

14. The method of claim 13, wherein the step of generating a lowest stratified mode cost value as a function of an air fuel ratio value, an exhaust gas recirculation value and a spark advance value comprises for each air fuel ratio value, exhaust gas recirculation value and spark advance value:

(a) setting an initial air fuel ratio value, an initial exhaust gas recirculation cost value and an initial spark advance cost value;

(b) determining an evaluation cost value as a function of said air fuel ratio value, said exhaust gas recirculation value and said spark advance value;

(c) comparing said evaluation cost value with said spark advance cost value;

(d) setting said spark advance value equal to said evaluation cost value where said evaluation cost value is lower than said spark advance value;

incrementing said spark advance value as a function of said exhaust gas recirculation value; and

repeating steps (b) through (d);

otherwise;

(e) comparing said spark advance cost value with said exhaust gas recirculation cost value;

(f) setting said exhaust gas recirculation cost value equal to said spark advance cost value where said where said spark advance cost value is lower than said exhaust gas recirculation cost value;

incrementing said exhaust gas recirculation value as a function of said stratified mode; and

repeating steps (a) through (f);

(g) comparing said exhaust gas recirculating cost value with said air fuel ratio cost value;

(h) setting said air fuel ratio cost value equal to said exhaust gas recirculating cost value where said air fuel ratio cost value is lower than said exhaust gas recirculating cost value;

incrementing said air fuel ratio value as a function of said stratified mode; and

repeating steps (a) through (h);

otherwise;

(i) setting said lowest stratified mode cost value equal to said air fuel ratio cost value.