Computer readable storage medium for controlling engine torque

• US 6,401,026 B2
• Filed: 06/25/2001
• Issued: 06/04/2002
• Est. Priority Date: 08/09/1999
• Status: Expired due to Term

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Pallett, Tobias John, Robichaux, Jerry Dean
• Primary Examiner(s): Kwon, John
• Application Number:
  US09/891,488
• Publication Number:
  US 20010037793A1
• Time in Patent Office: 344 Days
• Field of Search: 123/339.19, 123/361, 701/102, 701/110
• US Class Current: 701/110
• CPC Class Codes: F02D 2041/0017 by simultaneous control of throttle and exhaust gas recirculation
• CPC Class Codes: F02D 2041/1409 using at least a proportional, integral or derivative controller
• CPC Class Codes: F02D 2041/1422 Variable gain or coefficients
• CPC Class Codes: F02D 2200/1004 Estimation of the output torque
• CPC Class Codes: F02D 2200/1006 Engine torque losses, e.g. friction or pumping losses or losses caused by external loads of accessories
• CPC Class Codes: F02D 2250/18 Control of the engine output torque
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/083 taking into account engine load variation, e.g. air-conditionning
• CPC Class Codes: F02D 41/1497 With detection of the mechanical response of the engine
• CPC Class Codes: F02P 5/1504 with particular means during a transient phase, e.g. acceleration, deceleration, gear change during starting F02P5/1506
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A computer readable storage medium having instructions for controlling an engine includes instructions for determining a desired engine brake torque and modifying the desired engine brake torque based on current engine operating conditions to determine a requested engine brake torque prior to determination of control parameters, including at least one of an airflow and a fuel quantity, to effect the requested engine brake torque. Preferably, the desired engine brake torque is modified by combining the desired engine brake torque with an idle speed torque to generate a first intermediate torque, comparing the first intermediate torque to an actual engine brake torque to generate a second intermediate torque, generating a feedback correction torque based on the second intermediate torque, and combining the first intermediate torque, the feedback correction torque, and a third intermediate torque to determine the requested engine brake torque.

Claims

1. A computer readable storage medium having stored data representing instructions executable by a computer to control an engine, the computer readable storage medium comprising:

instructions for determining a desired engine brake torque based on accelerator pedal position, barometric pressure, and speed;

instructions for adjusting the desired engine brake torque to generate a requested engine brake torque based on current operating conditions; and

instructions for controlling at least one operating parameter of the engine based on the requested engine brake torque to deliver the desired engine brake torque.

2. The computer readable storage medium of claim 1 wherein the instructions for adjusting the desired engine brake torque comprise:

instructions for combining the desired engine brake torque with an idle speed torque, the idle speed torque determined at least in part based on a desired engine speed;

instructions for determining an actual engine brake torque; and

instructions for comparing the actual engine brake torque to the desired engine brake torque to generate a torque error.

3. The computer readable storage medium of claim 2 wherein the instructions for determining an actual engine brake torque comprise instructions for estimating an actual engine brake torque based on current engine operating parameters.

4. The computer readable storage medium of claim 3 wherein the instructions for adjusting the desired engine brake torque further comprise instructions for generating a requested brake torque based on the torque error to drive the torque error toward zero.

5. The computer readable storage medium of claim 3 wherein the instructions for generating a requested brake torque based on the torque error comprise:

instructions for applying the torque error to a PID feedback controller having associated proportional, integral, and derivative terms; and

instructions for setting the proportional and derivative terms to zero and holding the integral term constant during transient torque control modes.

6. The computer readable storage medium of claim 1 wherein the instructions for adjusting the desired engine brake torque comprise:

instructions for combining an accessory brake torque with the desired engine brake torque;

instructions for combining a frictional torque based on engine temperature with the desired engine brake torque;

instructions for compensating for torque reducing effects of spark retard and air/fuel ratio; and

wherein the instructions for controlling at least one operating parameter include instructions for controlling at least one of airflow and fuel flow.

7. A computer readable storage medium having stored data representing instructions for controlling an engine, the computer readable storage medium comprising:

instructions for determining a desired engine brake torque; and

instructions for modifying the desired engine brake torque based on current engine operating conditions to determine a requested engine brake torque prior to determination of control parameters, including at least one of an airflow and a fuel quantity, to effect the requested engine brake torque by combining the desired engine brake torque with an idle speed torque to generate a first intermediate torque, comparing the first intermediate torque to an actual engine brake torque to generate a second intermediate torque, generating a feedback correction torque based on the second intermediate torque, and combining the first intermediate torque, the feedback correction torque, and a third intermediate torque to determine the requested engine brake torque.

8. The computer readable storage medium of claim 7 wherein the third intermediate torque represents torque required to operate at least one engine accessory.

9. The computer readable storage medium of claim 7 wherein the third intermediate torque varies as a function of temperature and engine speed.

10. A computer readable storage medium having stored data representing instructions executable by a computer to control an internal combustion engine, the computer readable storage medium comprising:

instructions for determining a desired engine brake torque;

instructions for adjusting the desired engine brake torque to generate a requested engine brake torque by combining an accessory brake torque with the desired engine brake torque; and

instructions for controlling at least one operating parameter of the engine based on the requested engine brake torque to deliver the desired engine brake torque.