Rate-based contractive model predictive control method for internal combustion engine air path control

• US 9,562,484 B2
• Filed: 03/08/2013
• Issued: 02/07/2017
• Est. Priority Date: 12/21/2012
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation), Board of Regents of the University of Michigan (University of Michigan)
• Original Assignee: Toyota Motor Engineering & Manufacturing North America Incorporated (Toyota Motor Corporation), Board of Regents of the University of Michigan (University of Michigan)
• Inventors: Huang, Mike, Kolmanovsky, Ilya V.
• Primary Examiner(s): Vo, Hieu T
• Assistant Examiner(s): MANLEY, SHERMAN D
• Application Number:
  US13/791,035
• Publication Number:
  US 20140174414A1
• Time in Patent Office: 1,432 Days
• US Class Current: 1/1
• CPC Class Codes: F02D 2041/1412 using a predictive controller
• CPC Class Codes: F02D 2041/143 the control loop including a non-linear model or compensator
• CPC Class Codes: F02D 2041/1434 Inverse model
• CPC Class Codes: F02D 2200/0406 Intake manifold pressure
• CPC Class Codes: F02D 2200/101 Engine speed
• CPC Class Codes: F02D 41/0007 for control of turbo-charged or super-charged engines control of the pumps per se F02B37/12
• CPC Class Codes: F02D 41/0052 Feedback control of engine parameters, e.g. for control of air/fuel ratio or intake air amount
• CPC Class Codes: F02D 41/0072 Estimating, calculating or determining the EGR rate, amount or flow sensors in EGR systems F02M26/45
• CPC Class Codes: F02D 41/0077 Control of the EGR valve or actuator, e.g. duty cycle, closed loop control of position EGR valve position sensor F02M26/48
• CPC Class Codes: F02D 41/1401 characterised by the control or regulation method F02D41/1473, F02D41/1477 take precedence
• CPC Class Codes: F02D 41/1446 the characteristics being exhaust temperatures
• CPC Class Codes: F02D 41/1448 the characteristics being an exhaust gas pressure
• CPC Class Codes: F02M 26/05 High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
• CPC Class Codes: F02M 26/10 having means to increase the pressure difference between the exhaust and intake system, e.g. venturis, variable geometry turbines, check valves using pressure pulsations or throttles in the air intake or exhaust system
• CPC Class Codes: F02M 26/23 Layout, e.g. schematics
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A rate based model predictive controller and method for air path control for a diesel engine regulates intake manifold pressure (MAP) and EGR valve flow rate to specified set points by coordinated control of a variable geometry turbine (VGT) and EGR valve position. A decay and a flexible Lyapunov function is enforced on the rate based model predictive controller for a single step prediction and control arisen.

Claims

1. A system for controlling a variable geometry turbine and an EGR valve during engine operation, the system comprising:

an internal combustion engine; and

a controller configured to;

develop a non-linear model using engine operating parameters;

develop a linear quadratic model predictive controller, based on the non-linear model, for each engine operating zone; and

generate a rate based contractive predictive model based on the linear quadratic model, and use the rate based contractive predictive model responsive to engine intake manifold pressure and EGR valve flow rate to generate requested engine turbine lift and requested EGR flow rate.

2. The system of claim 1, wherein the controller is further configured for:

defining at least one engine operating zone about a center linearization point for engine speed ranges and fuel rate ranges.

3. The system of claim 2, wherein the controller is further configured for:

linearizing the non-linear model at a center linearization point within an engine operating zone.

4. The system of claim 3, wherein the controller is further configured for:

developing a second order reduced linear model used on the non-linear model.

5. The system of claim 4, wherein the controller is further configured for:

generating the rate-based predictive model as a derivative of the linear model.

6. The system of claim 5, wherein the controller is further configured for:

enforcing a Lyapunov function decay on the derivative of the linear model.

7. The system of claim 5, wherein the controller is further configured for:

generating a piecewise affine control law wherein;

u_k=u<sub>k−

1</sub>+T_s(F_ix_aug+G_i), if H_ix_aug≦

K_i

where iε

{1, . . . , n_r} denotes the i^th polyhedral region and (F_ix_aug+G_i) gives the requested control rates.

8. The system of claim 1, wherein the controller is further configured for:

applying partial inversion to the rate-based predictive model controller to convert an EGR valve flow rate signal to an EGR valve position duty cycle signal and to convert a turbine lift signal to a turbine lift duty cycle signal.

9. The system of claim 1, wherein the controller is further configured for:

reducing the number of regions in each of the at least one engine operating zone by using a single time instant to enforce overshoot restraint of at least one controller output.

10. The system of claim 9 wherein;

the single time instant includes 20 time steps.

11. The system of claim 7, wherein the controller is further configured for:

estimating an engine state;

determining the region of the piecewise affine control law based on the estimated engine state;

applying feedback gain associated with the selected region of the piecewise affine control law to determine a control rate; and

integrating the control rate to determine a control value to be applied to one engine input.

12. A method for controlling an internal combustion engine having a controller, the method comprising:

controlling a variable geometry turbine and an EGR valve during engine operation by using a computer program tangibly embodied on a computer usable medium and comprising instructions that when executed by a processor is configured to;

use a contractive rate-based predictive model, responsive to intake manifold pressure and requested EGR valve flow rate, to generate turbine lift and EGR flow rate;

define at least one engine operating zone about a center linearization point for engine speed ranges and fuel rate ranges; and

control operation of the internal combustion engine based on the generated engine turbine lift and EGR flow rate.

13. The method of claim 12 further comprising:

developing a non-linear model using operating parameters.

14. The method of claim 12, further comprising instructions for:

linearizing the non-linear model at a center linearization point within an engine operating zone.

15. The method of claim 14, further comprising instructions for:

generating the rate-based predictive model as a derivative of the linear model.

16. The method of claim 15, further comprising instructions for:

enforcing a Lyapunov function decay on the derivative of the linear model.

17. The method of claim 12, further comprising instructions for:

estimating an engine state;

determining the region of the piecewise affine control law based on the estimated engine state;

applying feedback gain associated with the selected region of the piecewise affine control law to determine a control rate; and

integrating the control rate to determine a control value to be applied to one engine input.