Diagnostic systems and methods using model predictive control

• US 9,382,865 B2
• Filed: 03/26/2014
• Issued: 07/05/2016
• Est. Priority Date: 03/26/2014
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Genslak, Robert J., Whitney, Christopher E.
• Primary Examiner(s): Vo, Hieu T
• Application Number:
  US14/225,531
• Publication Number:
  US 20150275806A1
• Time in Patent Office: 832 Days
• US Class Current: 1/1
• CPC Class Codes: F02D 11/105 characterised by the function converting demand to actuation, e.g. a map indicating relations between an accelerator pedal position and throttle valve opening or target engine torque
• CPC Class Codes: F02D 13/02 during engine operation
• CPC Class Codes: F02D 13/0207 changing valve lift or valve lift and timing
• CPC Class Codes: F02D 13/0219 by shifting the phase, i.e. the opening periods of the valves are constant
• CPC Class Codes: F02D 13/06 Cutting-out cylinders
• CPC Class Codes: F02D 17/00 Controlling engines by cutting out individual cylinders; Rendering engines inoperative or idling controlling or rendering inoperative by varying inlet or exhaust valve operating characteristics F02D13/00
• CPC Class Codes: F02D 17/02 Cutting-out cutting-out engines in multiple engine arrangements F02D25/04
• CPC Class Codes: F02D 2041/001 for engines with variable valve actuation
• CPC Class Codes: F02D 2041/0017 by simultaneous control of throttle and exhaust gas recirculation
• CPC Class Codes: F02D 2041/002 by simultaneous control of throttle and variable valve actuation
• CPC Class Codes: F02D 2041/1412 using a predictive controller
• CPC Class Codes: F02D 2041/1433 using a model or simulation of the system
• CPC Class Codes: F02D 21/04 with circulation of exhaust gases in closed or semi-closed circuits
• CPC Class Codes: F02D 2200/0814 Oxygen storage amount
• CPC Class Codes: F02D 2200/0816 Oxygen storage capacity
• CPC Class Codes: F02D 2200/1002 Output torque
• CPC Class Codes: F02D 2250/18 Control of the engine output torque
• CPC Class Codes: F02D 28/00 Programme-control of engines
• CPC Class Codes: F02D 29/02 peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers
• CPC Class Codes: F02D 35/023 by determining the cylinder pressure
• CPC Class Codes: F02D 41/0002 : Controlling intake air
• CPC Class Codes: F02D 41/005 : according to engine operating conditions
• CPC Class Codes: F02D 41/0087 : Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/1401 : characterised by the control or regulation method F02D41/1473, F02D41/1477 take precedence
• CPC Class Codes: F02D 41/1406 : with use of a optimisation method, e.g. iteration
• CPC Class Codes: F02D 41/1439 : characterised by the position of the sensor
• CPC Class Codes: F02D 41/1441 : Plural sensors
• CPC Class Codes: F02D 41/1454 : the characteristics being an oxygen content or concentration or the air-fuel ratio
• CPC Class Codes: F02D 41/222 : relating to the failure of sensors or parameter detection devices
• CPC Class Codes: F02D 41/30 : Controlling fuel injection F02D41/182, F02D41/24 take precedence
• CPC Class Codes: G05B 13/048 : using a predictor
• CPC Class Codes: G07C 5/0808 : Diagnosing performance data testing of vehicles G01M17/00; testing of electrical installation on vehicles G01R31/005
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 : Engine management systems

Abstract

A fuel control module transitions engine fueling from rich to lean. A catalyst fault detection module diagnoses whether a fault is present in an exhaust catalyst based on a response of an oxygen sensor to the transition. A prediction module generates a prediction based on a model and a set of possible target values. A cost module determines a cost for the set of possible target values based on comparisons of the prediction with minimum and maximums. Before the transition, a constraint module selectively adjusts at least one of the minimum and maximums for the fault diagnosis. Based on the cost, a selection module selects the set of possible target values from a group of sets of possible target values and sets target values based on the selected set of possible target values. An actuator module controls an engine actuator based on a first one of the target values.

Claims

1. An engine control system for a vehicle, comprising:

a fuel control module that transitions fueling of an engine from fuel rich to fuel lean;

a catalyst fault detection module that diagnoses whether a fault is present in an exhaust catalyst based on a response of an oxygen sensor to the transition, wherein the oxygen sensor is located one of upstream and downstream from the exhaust catalyst;

a prediction module that generates a predicted operating parameter of the engine based on a model of the engine and a set of possible target values determined based on an engine torque request;

a cost module that determines a cost for the set of possible target values based on comparisons of the predicted operating parameter with predetermined minimum and maximum values;

a constraint module that, before the transition, selectively adjusts at least one of the predetermined minimum and maximum values for the fault diagnosis;

a selection module that, based on the cost, selects the set of possible target values from a group including the set of possible target values and N other sets of possible target values determined based on the engine torque request, wherein N is an integer greater than zero, and that sets target values based on the selected set of possible target values; and

an actuator module that controls an engine actuator based on a first one of the target values.

2. The engine control system of claim 1 further comprising a sensor fault detection module that diagnoses whether a second fault is present in the oxygen sensor based on the response of the oxygen sensor to the transition.

3. The engine control system of claim 1 wherein the cost module increases the cost for the set of possible target values when one of:

the predicted operating parameter is less than the predetermined minimum value; and

the predicted operating parameter is greater than the predetermined maximum value.

4. The engine control system of claim 1 wherein the constraint module maintains the at least one of the predetermined minimum and maximum values during the transition and while the fueling of the engine is lean.

5. The engine control system of claim 1 wherein:

the prediction module generates a predicted amount of air per cylinder (APC) of the engine based on the model of the engine and the set of possible target values;

the cost module determines the cost for the set of possible target values based on comparisons of the predicted amount of APC with a predetermined minimum amount of APC and a predetermined maximum amount of APC; and

the constraint module selectively adjusts at least one of the predetermined minimum amount of APC and the predetermined maximum amount of APC for the fault diagnosis.

6. The engine control system of claim 1 wherein:

the prediction module generates a predicted coefficient of variation (COV) of indicated mean effective pressure (IMEP) of the engine based on the model of the engine and the set of possible target values;

the cost module determines the cost for the set of possible target values based on comparisons of the predicted COV of IMEP with a predetermined minimum value and a predetermined maximum value; and

the constraint module selectively adjusts at least one of the predetermined minimum value and the predetermined maximum value for the fault diagnosis.

7. The engine control system of claim 1 wherein:

the prediction module generates a predicted amount of residual dilution of the engine based on the model of the engine and the set of possible target values;

the cost module determines the cost for the set of possible target values based on comparisons of the predicted amount of residual dilution with a predetermined minimum residual dilution amount and a predetermined maximum residual dilution amount; and

the constraint module selectively adjusts at least one of the predetermined minimum residual dilution amount and the predetermined maximum residual dilution amount for the fault diagnosis.

8. The engine control system of claim 1 wherein:

the prediction module generates a predicted amount of external dilution of the engine based on the model of the engine and the set of possible target values;

the cost module determines the cost for the set of possible target values based on comparisons of the predicted amount of external dilution with a predetermined minimum external dilution amount and a predetermined maximum external dilution amount; and

the constraint module selectively adjusts at least one of the predetermined minimum external dilution amount and the predetermined maximum external dilution amount for the fault diagnosis.

9. The engine control system of claim 1 further comprising:

a throttle actuator module that controls opening of a throttle valve based on the first one of the target values;

a boost actuator module that controls opening of a wastegate of a turbocharger based on a second one of the target values;

an exhaust gas recirculation (EGR) actuator module that controls opening of an EGR valve based on a third one of the target values; and

a phaser actuator module that controls intake and exhaust valve phasing based on fourth and fifth ones of the target values.

10. The engine control system of claim 1 wherein:

the prediction module further generates N other predicted operating parameters of the engine based on the model of the engine and the N other sets of possible target values, respectively;

the cost module further determines N other costs for the N other sets of possible target values, respectively, based on comparisons of the N other predicted operating parameters with the predetermined minimum and maximum values; and

the selection module selects the set of possible target values from the group including the set of possible target values and the N other sets of possible target values when the cost for the set of possible target values is less than the each of the N other costs.

11. An engine control method for a vehicle, comprising:

transitioning fueling of an engine from fuel rich to fuel lean;

diagnosing whether a fault is present in an exhaust catalyst based on a response of an oxygen sensor to the transition, wherein the oxygen sensor is located one of upstream and downstream from the exhaust catalyst;

generating a predicted operating parameter of the engine based on a model of the engine and a set of possible target values determined based on an engine torque request;

determining a cost for the set of possible target values based on comparisons of the predicted operating parameter with predetermined minimum and maximum values;

before the transition, selectively adjusting at least one of the predetermined minimum and maximum values for the fault diagnosis;

based on the cost;

selecting the set of possible target values from a group including the set of possible target values and N other sets of possible target values determined based on the engine torque request, wherein N is an integer greater than zero; and

setting target values based on the selected set of possible target values; and

controlling an engine actuator based on a first one of the target values.

12. The engine control method of claim 11 further comprising diagnosing whether a second fault is present in the oxygen sensor based on the response of the oxygen sensor to the transition.

13. The engine control method of claim 11 further comprising increasing the cost for the set of possible target values when one of:

the predicted operating parameter is less than the predetermined minimum value; and

the predicted operating parameter is greater than the predetermined maximum value.

14. The engine control method of claim 11 further comprising maintaining the at least one of the predetermined minimum and maximum values during the transition and while the fueling of the engine is lean.

15. The engine control method of claim 11 further comprising:

generating a predicted amount of air per cylinder (APC) of the engine based on the model of the engine and the set of possible target values;

determining the cost for the set of possible target values based on comparisons of the predicted amount of APC with a predetermined minimum amount of APC and a predetermined maximum amount of APC; and

selectively adjusting at least one of the predetermined minimum amount of APC and the predetermined maximum amount of APC for the fault diagnosis.

16. The engine control method of claim 11 further comprising:

generating a predicted coefficient of variation (COV) of indicated mean effective pressure (IMEP) of the engine based on the model of the engine and the set of possible target values;

determining the cost for the set of possible target values based on comparisons of the predicted COV of IMEP with a predetermined minimum value and a predetermined maximum value; and

selectively adjusting at least one of the predetermined minimum value and the predetermined maximum value for the fault diagnosis.

17. The engine control method of claim 11 further comprising:

generating a predicted amount of residual dilution of the engine based on the model of the engine and the set of possible target values;

determining the cost for the set of possible target values based on comparisons of the predicted amount of residual dilution with a predetermined minimum residual dilution amount and a predetermined maximum residual dilution amount; and

selectively adjusting at least one of the predetermined minimum residual dilution amount and the predetermined maximum residual dilution amount for the fault diagnosis.

18. The engine control method of claim 11 further comprising:

generating a predicted amount of external dilution of the engine based on the model of the engine and the set of possible target values;

determining the cost for the set of possible target values based on comparisons of the predicted amount of external dilution with a predetermined minimum external dilution amount and a predetermined maximum external dilution amount; and

selectively adjusting at least one of the predetermined minimum external dilution amount and the predetermined maximum external dilution amount for the fault diagnosis.

19. The engine control method of claim 11 further comprising:

controlling opening of a throttle valve based on the first one of the target values;

controlling opening of a wastegate of a turbocharger based on a second one of the target values;

controlling opening of an exhaust gas recirculation (EGR) valve based on a third one of the target values; and

controlling intake and exhaust valve phasing based on fourth and fifth ones of the target values.

20. The engine control method of claim 11 further comprising:

generating N other predicted operating parameters of the engine based on the model of the engine and the N other sets of possible target values, respectively;

determining N other costs for the N other sets of possible target values, respectively, based on comparisons of the N other predicted operating parameters with the predetermined minimum and maximum values; and

selecting the set of possible target values from the group including the set of possible target values and the N other sets of possible target values when the cost for the set of possible target values is less than the each of the N other costs.