Airflow-based output torque estimation for multi-displacement engine

• US 7,085,647 B1
• Filed: 03/21/2005
• Issued: 08/01/2006
• Est. Priority Date: 03/21/2005
• Status: Active Grant

• Current Assignee: FCA US LLC (Stellantis NV)
• Original Assignee: Daimler Chrysler Corporation (Mercedes-Benz Group AG)
• Inventors: Prucka, Michael J, Ohl, Gregory L, Bonne, Michael A
• Primary Examiner(s): Vo, Hieu T.
• Application Number:
  US11/085,423
• Time in Patent Office: 498 Days
• Field of Search: 701/114, 701/110, 701/115, 701/102, 701/107, 123/350, 123/319, 123/352, 123/399, 123/361, 123/480
• US Class Current: 701/114
• CPC Class Codes: F02D 2200/0406 Intake manifold pressure
• CPC Class Codes: F02D 2200/1004 Estimation of the output torque
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123

Abstract

A method for estimating an output torque generated by a multi-displacement engine operating in a partial-displacement mode includes multiplying a measure representing a mass air flow through the engine'"'"'s intake manifold by a engine-speed-based mass-air-flow-to-torque conversion factor, and thereafter summing the product with a torque offset value likewise based on engine speed data, to obtain a base indicated potential output torque. The base indicated potential output torque is then multiplied with a torque-based efficiency conversion factor representing at least one of a partial-displacement mode spark efficiency, fuel-air-ratio efficiency, and exhaust gas recirculation efficiency, and the resulting product is summed with a torque-based frictional loss measure to obtain the desired estimated engine output torque. The estimated engine output torque is particularly useful in determining whether a transition from the partial-displacement engine operating mode to a full-displacement engine operating mode is desired.

Claims

1. A method for estimating an output torque generated by a multi-displacement internal combustion engine operating in a partial-displacement mode, the engine including an intake manifold and an engine speed sensor generating engine speed data, the method comprising:

providing a first measure representing a mass air flow through the intake manifold;

determining a mass-air-flow-to-torque conversion factor and a mass-air-flow-to-torque offset based on the engine speed data;

multiplying the first measure by the conversion factor to obtain a second measure representing a pre-offset base indicated torque;

summing the second measure with the torque offset to obtain a third measure representing a base indicated potential torque; and

multiplying the base indicated potential torque measure with a torque-based efficiency conversion factor representing at least one of a spark efficiency measure, a fuel-air-ratio efficiency measure, and an exhaust gas recirculation efficiency measure, to obtain a third measure representing an efficiency-corrected indicated potential torque measure.

2. The method of claim 1, wherein providing includes determining the first measure based on a detected manifold air pressure and the engine speed data.

3. The method of claim 1, wherein the first measure further represents a maximum mass air flow through the intake manifold, and wherein determining the first measure is further based on at least one of a barometric pressure, an inlet air temperature, an engine coolant temperature, and an exhaust gas oxygen content.

4. The method of claim 3, wherein the first measure represents the maximum mass air flow through the intake manifold in a full-displacement engine operating mode, and wherein the first measure is further determined by multiplying the maximum mass air flow by a partial-displacement correction factor.

5. The method of claim 1, further including calculating an average engine speed based on the engine speed data, and wherein determining the mass-air-flow-to-torque conversion factor is based on the average engine speed, and determining the torque offset is based on the average engine speed.

6. The method of claim 1, wherein determining the mass-air-flow-to-torque conversion factor includes retrieving a first value from a first lookup table using the engine speed data.

7. The method of claim 1, wherein determining the torque offset includes retrieving a second value from a second lookup table using the engine speed data.

8. The method of claim 1, further including summing the third measure with a torque-based frictional loss measure.

9. A method for estimating an output torque generated by a multi-displacement internal combustion engine operating in a partial-displacement mode, the engine including an intake manifold and an engine speed sensor generating engine speed data, the method comprising:

determining a first measure representing a mass air flow through the intake manifold based on a detected manifold air pressure and the engine speed data providing;

determining a mass-air-flow-to-torque conversion factor and a mass-air-flow-to-torque offset based on the engine speed data;

multiplying the first measure by the conversion factor to obtain a second measure representing a pre-offset base indicated torque;

summing the second measure with the torque offset to obtain a third measure representing a base indicated potential torque;

multiplying the base indicated potential torque measure with a torque-based efficiency conversion factor representing at least one of a spark efficiency measure, a fuel-air-ratio efficiency measure, and an exhaust gas recirculation efficiency measure, to obtain a third measure representing an efficiency-corrected indicated potential torque measure; and

summing the third measure with a torque-based frictional loss measure to obtain the estimated output torque.

10. The method of claim 9, wherein the first measure represents a maximum mass air flow through the intake manifold, and wherein determining the first measure is further based on at least one of a barometric pressure, an inlet air temperature, an engine coolant temperature, and an exhaust gas oxygen content.

11. The method of claim 10, wherein the first measure represents the maximum mass air flow through the intake manifold in a full-displacement engine operating mode, and wherein the first measure is further determined by multiplying the maximum mass air flow by a partial-displacement correction factor.

12. The method of claim 9, further including calculating an average engine speed based on the engine speed data, and wherein determining the mass-air-flow-to-torque conversion factor is based on the average engine speed, and determining the torque offset is based on the average engine speed.

13. The method of claim 9, wherein determining the mass-air-flow-to-torque conversion factor includes retrieving a first value from a first lookup table using the engine speed data.

14. The method of claim 9, wherein determining the torque offset includes retrieving a second value from a second lookup table using the engine speed data.