Adaptive torque model for internal combustion engine

• US 6,553,958 B1
• Filed: 04/11/2001
• Issued: 04/29/2003
• Est. Priority Date: 04/11/2001
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Buckland, Julia Helen, Sun, Jing, Kolmanovsky, Ilya V
• Primary Examiner(s): Kwon, John
• Application Number:
  US09/833,237
• Time in Patent Office: 748 Days
• Field of Search: 123/352, 123/295, 123/294, 123/296, 123/305, 123/350, 123/351
• US Class Current: 123/295
• CPC Class Codes: F02B 17/005 having direct injection in the combustion chamber
• CPC Class Codes: F02B 2075/125 Direct injection in the combustion chamber for spark ignition engines, i.e. not in pre-combustion chamber
• CPC Class Codes: F02B 23/104 the injector being placed on a side position of the cylinder
• CPC Class Codes: F02D 2041/1433 using a model or simulation of the system
• CPC Class Codes: F02D 2200/1004 Estimation of the output torque
• CPC Class Codes: F02D 2250/18 Control of the engine output torque
• CPC Class Codes: F02D 41/0097 using means for generating speed signals
• CPC Class Codes: F02D 41/1402 Adaptive control
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A system and method for controlling a multi-cylinder internal combustion engine include determining a first engine operating variable using a model having at least one adjustable model parameter, measuring a second engine operating variable, and modifying the at least one adjustable model parameter based on a relationship between the first and second engine operating variables. In one embodiment, the first engine operating variable represents engine torque while the second engine operating variable is engine speed. An engine torque model and/or load torque model may be used to determine an estimated engine speed or speed trajectory which is compared to the actual engine speed or trajectory determined using an engine speed sensor. One or more model parameters for the engine torque and/or load torque model are adjusted when appropriate operating conditions are met based on a difference between the predicted or estimated engine speeds and the measured engine speeds.

Claims

1. A method for controlling a multi-cylinder internal combustion engine, the method comprising:

determining a first engine operating variable using a model having at least one adjustable model parameter;

wherein the step of determining a first engine operating variable comprises;

estimating engine torque for current operating conditions;

estimating load torque for current operating conditions; and

determining an estimated engine speed based on the estimated engine torque and estimated load torque;

measuring a second engine operating variable using an associated sensor;

modifying at least one adjustable model parameter based on a relationship between the first and second engine operating variables to adapt the model for variations in engine operation;

comparing the estimated engine speed to an actual engine speed determined using an engine speed sensor; and

wherein the step of modifying the at least one adjustable model parameter includes modifying the model parameter based on a difference between the estimated and actual engine speeds, wherein the step of modifying is performed only if the difference between the estimated and actual engine speeds exceeds a corresponding threshold.

2. A method for controlling a multi-cylinder internal combustion engine, the method comprising:

determining a first engine operating variable using a model having at least one adjustable model parameter, wherein the step of determining a first engine operating variable comprises;

estimating engine torque for current operating conditions;

estimating load torque for current operating conditions; and

determining an estimated engine speed based on the estimated engine torque and estimated load torque;

measuring a second engine operating variable using an associated sensor; and

modifying at least one adjustable model parameter based on a relationship between the first and second engine operating variables to adapt the model for variations in engine operation, wherein the estimated engine speed is periodically reset to actual engine speed as determined by an engine speed sensor.

3. A method for controlling a multi-cylinder internal combustion engine, the method comprising:

determining a first engine operating variable using a model having at least one adjustable model parameter, wherein the step of determining a first engine operating variable comprises;

estimating engine torque for current operating conditions;

estimating load torque for current operating conditions; and

determining an estimated engine speed based on the estimated engine torque and estimated load torque;

measuring a second engine operating variable using an associated sensor; and

modifying at least one adjustable model parameter based on a relationship between the first and second engine operating variables to adapt the model for variations in engine operation, wherein the multi-cylinder internal combustion engine is a direct injection spark ignition engine having a plurality of combustion modes of operation and wherein the estimated engine speed is periodically reset to the actual engine speed at each change of combustion mode of operation.

4. A method for controlling a multi-cylinder internal combustion engine, the method comprising:

determining a first engine operating variable using a model having at least one adjustable model parameter, wherein the step of determining a first engine operating variable comprises;

estimating engine torque for current operating conditions;

estimating load torque for current operating conditions; and

determining an estimated engine speed based on the estimated engine torque and estimated load torque;

measuring a second engine operating variable using an associated sensor;

modifying at least one adjustable model parameter based on a relationship between the first and second engine operating variables to adapt the model for variations in engine operation;

determining an actual engine speed using an engine speed sensor;

comparing the actual engine speed to the estimated engine speed to determine an engine speed difference; and

resetting the estimated engine speed to the actual engine speed when the engine speed difference exceeds a corresponding threshold.

5. A system for controlling a direct injection spark ignition multi-cylinder internal combustion engine operable in at least a homogeneous mode and a stratified mode using a torque model to determine an estimated engine torque, the system comprising:

an engine speed sensor for measuring actual rotational speed of the engine;

a controller in communication with the engine speed sensor, the controller determining an estimated engine torque based on current engine operating and control variables, determining an estimated engine load torque, determining an estimated engine speed based on the estimated engine torque and the estimated engine load torque, and adjusting at least one parameter of the engine torque model based on a difference between the estimated engine speed and the actual rotational speed of the engine.

6. The system of claim 5 wherein the controller determines a load torque corresponding to a manual or automatic transmission and an accessory load torque corresponding to operation of engine or vehicle accessories.

7. The system of claim 5 wherein the controller periodically resets the estimated engine speed to the actual rotational speed of the engine.

8. The system of claim 5 wherein the controller resets the estimated engine speed to the actual engine speed when the combustion mode changes between homogeneous and stratified operating modes.

9. The system of claim 5 wherein the controller resets the estimated engine speed to the actual engine speed when the difference between the actual and estimated engine speeds exceeds a corresponding error threshold.

10. The system of claim 5 wherein the controller adjusts the at least one model parameter only if the difference between estimated and actual engine speed exceeds a corresponding adapting threshold.

11. The system of claim 5 wherein the controller determines whether current operating conditions have attained steady state operation before adjusting the at least one model parameter.