FEED-FORWARD CAMSHAFT PHASER CONTROL SYSTEMS AND METHODS

• US 20110264342A1
• Filed: 04/22/2010
• Published: 10/27/2011
• Est. Priority Date: 04/22/2010
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Whitney, Christopher E., Pitsch, Michael J., Baur, Andrew W.
• Granted Patent: US 8,346,447 B2
• Time in Patent Office: Days
• US Class Current: 701/54
• CPC Class Codes: F02D 2041/001 for engines with variable valve actuation
• CPC Class Codes: F02D 2041/0012 with selective deactivation of cylinders
• CPC Class Codes: F02D 2041/002 by simultaneous control of throttle and variable valve actuation
• CPC Class Codes: F02D 2200/10 Parameters related to the engine output, e.g. engine torque or engine speed
• CPC Class Codes: F02D 2200/501 Vehicle speed
• CPC Class Codes: F02D 2200/602 Pedal position
• CPC Class Codes: F02D 37/02 one of the functions being ignition
• CPC Class Codes: F02D 41/0002 Controlling intake air
• CPC Class Codes: F02D 41/0097 using means for generating speed signals
• CPC Class Codes: F02D 41/023 in relation with the gear ratio shifting conjoint control for improving gear change B60W30/19
• 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

An engine control system includes an inertia phase detection module, a feed-forward (FF) engine speed module, a FF APC module, a FF phaser postion module, and a phaser control module. The inertia phase detection module determines when an inertia phase of a gear shift is occurring within a transmission. The FF engine speed module predicts an engine speed for a future time when the inertia phase ends. The FF APC module predicts an air-per-cylinder (APC) for the future time based on the engine speed. The FF phaser position module determines a FF phaser position based on the engine speed and the APC. The phaser control module controls a camshaft phaser position based on the FF phaser position during the inertia phase of the gear shift.

Claims

1. An engine control system comprising:

an inertia phase detection module that determines when an inertia phase of a gear shift is occurring within a transmission;

a feed-forward (FF) engine speed module that predicts an engine speed for a future time when the inertia phase ends;

a FF APC module that predicts an air-per-cylinder (APC) for the future time based on the engine speed;

a FF phaser position module that determines a FF phaser position based on the engine speed and the APC; and

a phaser control module that controls a camshaft phaser position based on the FF phaser position during the inertia phase of the gear shift.

2. The engine control system of claim 1 further comprising a target phaser position module that determines a target phaser position,

wherein the phaser control module controls the camshaft phaser position based on the target phaser position before the inertia phase begins and after the inertia phase ends.

3. The engine control system of claim 2 wherein the target phaser position module determines the target phaser position based on a second engine speed measured by an engine speed sensor and a target APC.

4. The engine control system of claim 2 further comprising a rate limit determination module that sets a rate limit based on whether the inertia phase is occurring,

wherein the phaser control module applies the rate limit in controlling the camshaft phaser position.

5. The engine control system of claim 4 wherein the rate limit determination module sets the rate limit to first rate limit during the inertia phase of the gear shift and that sets the rate limit to a second rate limit before and after the inertia phase, and

wherein the first rate limit is greater than the second rate limit.

6. The engine control system of claim 2 further comprising a phaser actuator module that controls the camshaft phaser position based on a commanded phaser position,

wherein the phaser control module ramps the commanded phaser position from the target phaser position to the FF phaser position during the inertia phase of the gear shift.

7. The engine control system of claim 6 wherein the phaser control module determines a number of steps based on a period of the inertia phase of the gear shift, determines a magnitude for each of the steps based on a difference between the target phaser position and the FF phaser position, and ramps the commanded phaser position from the target phaser position to the FF phaser position during the inertia phase using the number of steps of the magnitude.

8. The engine control system of claim 7 wherein the phaser control module determines the magnitude for each of the steps based on a quotient of the difference over the number of steps.

9. The engine control system of claim 1 further comprising a FF torque module that determines a FF torque for the future time based on the engine speed and a driver torque request,

wherein the FF APC module determines the FF APC based on the FF torque.

10. The engine control system of claim 1 wherein the inertia phase detection module determines that the inertia phase of the gear shift is occurring when a commanded gear from a transmission control module is different than a current gear selected within the transmission, a shift timer is greater than a predetermined period, and the current gear at a current time is different than the current gear at a previous time, and

wherein the shift timer tracks a period between the current time and when the commanded gear transitioned from being equal to the current gear to being different than the current gear.

11. An engine control method comprising:

determining when an inertia phase of a gear shift is occurring within a transmission;

predicting an engine speed for a future time when the inertia phase ends;

predicting an air-per-cylinder (APC) for the future time based on the engine speed;

determining a feed-forward (FF) phaser position based on the engine speed and the APC; and

controlling a camshaft phaser position based on the FF phaser position during the inertia phase of the gear shift.

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

determining a target phaser position; and

controlling the camshaft phaser position based on the target phaser position before the inertia phase begins and after the inertia phase ends.

13. The engine control method of claim 12 further comprising determining the target phaser position based on a second engine speed measured by an engine speed sensor and a target APC.

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

setting a rate limit based on whether the inertia phase is occurring; and

applying the rate limit in controlling the camshaft phaser position.

15. The engine control method of claim 14 further comprising:

setting the rate limit to first rate limit during the inertia phase of the gear shift; and

setting the rate limit to a second rate limit before and after the inertia phase,

wherein the first rate limit is greater than the second rate limit.

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

controlling the camshaft phaser position based on a commanded phaser position; and

ramping the commanded phaser position from the target phaser position to the FF phaser position during the inertia phase of the gear shift.

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

determining a number of steps based on a period of the inertia phase of the gear shift;

determining a magnitude for each of the steps based on a difference between the target phaser position and the FF phaser position; and

ramping the commanded phaser position from the target phaser position to the FF phaser position during the inertia phase using the number of steps of the magnitude.

18. The engine control method of claim 17 further comprising determining the magnitude for each of the steps based on a quotient of the difference over the number of steps.

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

determining a FF torque for the future time based on the engine speed and a driver torque request; and

determining the FF APC based on the FF torque.

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

determining that the inertia phase of the gear shift is occurring when a commanded gear from a transmission control module is different than a current gear selected within the transmission, a shift timer is greater than a predetermined period, and the current gear at a current time is different than the current gear at a previous time; and

tracking a period between the current time and when the commanded gear transitioned from being equal to the current gear to being different than the current gear using the shift timer.