Increased fuel economy mode control systems and methods

• US 8,473,179 B2
• Filed: 07/28/2010
• Issued: 06/25/2013
• Est. Priority Date: 07/28/2010
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Whitney, Christopher E., Baur, Andrew W., Spitza, Alfred E. Jr., Li, Zhong, Kaiser, Jeffrey M.
• Primary Examiner(s): Vo, Hieu T
• Application Number:
  US12/845,164
• Publication Number:
  US 20120029787A1
• Time in Patent Office: 1,063 Days
• Field of Search: 701/102, 701/103, 701/104, 701/84, 123/198.F
• US Class Current: 701/102
• CPC Class Codes: F01L 1/34 characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
• CPC Class Codes: F01L 13/0005 Deactivating valves
• 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 2041/0012 with selective deactivation of cylinders
• CPC Class Codes: F02D 2200/0406 Intake manifold pressure
• CPC Class Codes: F02D 2200/0414 Air temperature
• CPC Class Codes: F02D 2250/18 Control of the engine output torque
• CPC Class Codes: F02D 2250/22 by keeping a torque reserve, i.e. with temporarily reduced drive train or engine efficiency
• CPC Class Codes: F02D 41/0002 Controlling intake air
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/0225 in relation with the gear ratio or shift lever position
• CPC Class Codes: F02D 41/1497 With detection of the mechanical response of the engine
• CPC Class Codes: F02D 41/1498 measuring engine roughness
• 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: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

An engine control system includes a desired manifold absolute pressure (MAP) module, a MAP to torque module, a threshold determination module, and a fuel economy (FE) mode module. The desired MAP module determines a desired MAP for operation of an engine in one of a cylinder deactivation mode and a low-lift mode based on a difference between a desired vacuum and an air pressure upstream of a throttle valve. The MAP to torque module determines a desired torque output of the engine for operation in the one of the cylinder deactivation mode and the low-lift mode based on the desired MAP. The threshold determination module determines an entry torque based on the desired torque output. The FE mode module selectively triggers operation in the one of the cylinder deactivation mode and the low-lift mode based on a comparison of the entry torque and a torque request.

Claims

1. An engine control system comprising:

a desired manifold absolute pressure (MAP) module that determines a desired MAP for operation of an engine in one of a cylinder deactivation mode and a low-lift mode based on a difference between a desired vacuum and an air pressure upstream of a throttle valve;

a MAP to torque module that determines a desired torque output of the engine for operation in the one of the cylinder deactivation mode and the low-lift mode based on the desired MAP;

a threshold determination module that determines an entry torque based on the desired torque output; and

a fuel economy (FE) mode module that selectively triggers operation in the one of the cylinder deactivation mode and the low-lift mode based on a comparison of the entry torque and a torque request.

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

a noise, vibration, and harshness (NVH) torque determination module that determines an NVH torque,

wherein an NVH value is greater than a predetermined value when an actual torque output of the engine during operation in the one of the cylinder deactivation mode and the low-lift mode is greater than the NVH torque; and

a maximum torque module that sets a maximum torque output for operation in the one of the cylinder deactivation mode and the low-lift mode equal to one of the NVH torque and the desired torque output,

wherein the threshold determination module determines the entry torque based on the maximum torque output.

3. The engine control system of claim 2 wherein the maximum torque module sets the maximum torque output equal to a lesser one of the NVH torque and the desired torque output.

4. The engine control system of claim 2 wherein the threshold determination module sets the entry torque further based on a gear ratio.

5. The engine control system of claim 2 wherein the NVH torque determination module determines the NVH torque based on a gear ratio, an engine speed, and an ambient air temperature.

6. The engine control system of claim 2 further comprising:

an actuation module that determines an air torque request based on the torque request; and

an air control module that limits to the air torque request to the maximum torque output during operation in the one of the cylinder deactivation mode and the low-lift mode to determine a limited air torque request and that determines a desired MAP, a desired air per cylinder (APC), and a desired throttle area based on the limited air torque request.

7. The engine control system of claim 2 wherein the threshold determination module further determines an exit torque based on the maximum torque output, and

wherein the FE mode module selectively disables operation in the one of the cylinder deactivation mode and the low-lift mode based on a second comparison of the torque request and the exit torque.

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

a correction module that determines a MAP to torque correction based on a first difference between a first torque and a second torque, that determines the first torque using a first relationship between an actual APC and the first torque, and that determines the second torque using a second relationship between a measured MAP and the second torque,

wherein the MAP to torque module determines an uncorrected desired torque output of the engine for operation in the one of the cylinder deactivation mode and the low-lift mode based on the desired MAP and determines the desired torque output based on the MAP to torque correction and the uncorrected desired torque.

9. The engine control system of claim 8 wherein the MAP to torque module sets the desired torque output to a sum of the MAP to torque correction and the uncorrected desired torque.

10. The engine control system of claim 8 further comprising:

a MAP to APC module that determines a desired air per cylinder (APC) for the engine during operation in the one of the cylinder deactivation mode and the low-lift mode based on the desired MAP;

a MAP correction module that determines a corrected APC based on the desired APC and a MAP to APC correction; and

an optimum spark timing module that determines an optimum spark timing based on the corrected APC;

wherein the correction module further determines the MAP to APC correction based on a second difference between an estimated APC and the actual APC, and

wherein the MAP to torque module determines the desired torque output further based on the optimum spark timing.

11. An engine control method comprising:

determining a desired manifold absolute pressure (MAP) for operation of an engine in one of a cylinder deactivation mode and a low-lift mode based on a difference between a desired vacuum and an air pressure upstream of a throttle valve;

determining a desired torque output of the engine for operation in the one of the cylinder deactivation mode and the low-lift mode based on the desired MAP;

determining an entry torque based on the desired torque output; and

selectively triggering operation in the one of the cylinder deactivation mode and the low-lift mode based on a comparison of the entry torque and a torque request.

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

determining a noise, vibration, and harshness (NVH) torque,

wherein an NVH value is greater than a predetermined value when an actual torque output of the engine during operation in the one of the cylinder deactivation mode and the low-lift mode is greater than the NVH torque;

setting a maximum torque output for operation in the one of the cylinder deactivation mode and the low-lift mode equal to one of the NVH torque and the desired torque output; and

determining the entry torque based on the maximum torque output.

13. The engine control method of claim 12 further comprising setting the maximum torque output equal to a lesser one of the NVH torque and the desired torque output.

14. The engine control method of claim 12 further comprising setting the entry torque further based on a gear ratio.

15. The engine control method of claim 12 further comprising determining the NVH torque based on a gear ratio, an engine speed, and an ambient air temperature.

16. The engine control method of claim 12 further comprising:

determining an air torque request based on the torque request;

limiting to the air torque request to the maximum torque output during operation in the one of the cylinder deactivation mode and the low-lift mode to determine a limited air torque request; and

determining a desired MAP, a desired air per cylinder (APC), and a desired throttle area based on the limited air torque request.

17. The engine control method of claim 12 further comprising:

determining an exit torque based on the maximum torque output; and

selectively disabling operation in the one of the cylinder deactivation mode and the low-lift mode based on a second comparison of the torque request and the exit torque.

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

determining a MAP to torque correction based on a first difference between a first torque and a second torque;

determining the first torque using a first relationship between an actual APC and the first torque;

determining the second torque using a second relationship between a measured MAP and the second torque;

determining an uncorrected desired torque output of the engine for operation in the one of the cylinder deactivation mode and the low-lift mode based on the desired MAP; and

determining the desired torque output based on the MAP to torque correction and the uncorrected desired torque.

19. The engine control method of claim 18 further comprising setting the desired torque output to a sum of the MAP to torque correction and the uncorrected desired torque.

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

determining a desired air per cylinder (APC) for the engine during operation in the one of the cylinder deactivation mode and the low-lift mode based on the desired MAP;

determining a corrected APC based on the desired APC and a MAP to APC correction;

determining an optimum spark timing based on the corrected APC;

determining the MAP to APC correction based on a second difference between an estimated APC and the actual APC; and

determining the desired torque output further based on the optimum spark timing.