Vehicle Response During Vehicle Acceleration Conditions

Abstract

A vehicle control method for transitioning through transmission lash regions is described using a variety of information, such as, for example, gear ratio, clutch slippage, etc. Further, different adjustment of spark and throttle angle is used to provide a rapid torque response while still reducing effects of the lash. Finally, transitions taking into account both slipping and non-slipping transmissions are described.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a vehicle illustrating various powertrain components;

FIG. 2 is a block diagram of an engine;

FIG. 3 is a high level flowchart of a routine for controlling the engine and powertrain;

FIG. 4 is a graph illustrating example operation;

FIG. 5 is a state diagram of example control logic and routines;

FIG. 6 is a timing diagram showing example operation according to FIG. 5;

FIG. 7 is a graph illustrating additional example operation; and

FIGS. 8-11 are high level flowcharts of routines for controlling the engine and powertrain.

Claims

1. A vehicle control method for a vehicle having powertrain with an internal combustion engine and a transmission having a clutch, the method comprising: transitioning through a lash region of the transmission by adjusting engine output torque, where said adjustment is based on whether clutch slipping is present in the transmission during said transition, where during said transition, ignition timing is retarded while adjusting engine airflow to, and then spark angle is advanced to rapidly provide output torque.

2. The method of claim 1 wherein said adjustment is further based on a degree of clutch slipping.

3. The method of claim 2 wherein said clutch is a torque converter clutch.

4. The method of claim 2 wherein said clutch slipping is present when said torque converter is un-locked.

5. The method of claim 1 wherein said ignition timing is adjusted based on a gear ratio of the transmission.

6. The method of claim 1 wherein said lash region is detected based on at least one of torque converter speeds and estimated engine torque.

7. The method of claim 3 wherein an end of said lash region is detected based on a whether torque converter clutch slip is greater than a first threshold, estimated engine torque is greater than a second threshold, commanded torque is greater than a third threshold, and a duration of said lash region.

8. A vehicle control method for a vehicle having an internal combustion engine coupled to a torque converter, the torque converter having an input speed and an output speed, the torque converter coupled to a transmission, the transmission coupled to wheels on a road, the method comprising: in response to a driver tip-out during at least some conditions, decreasing powertrain output so that positive torque is not transmitted to the wheels;and after said tip-out and in response to a driver tip-in, and at least during transitioning to transmission of positive powertrain torque to the wheels, retarding ignition timing while adjusting engine airflow until torque converter input speed is greater than torque converter output speed, and then advancing spark angle to rapidly provide output torque, where said ignition timing and airflow are further adjusted based on a transmission gear change.

9. The method of claim 8 wherein said clutch is a torque converter lock-up clutch.

10. The method of claim 8 wherein said transmission gear change is a commanded gear change of the transmission.

11. The method of claim 8 wherein said transmission gear change is an actual gear change of the transmission.

12. A vehicle control method for a vehicle having powertrain with an internal combustion engine, a torque converter having an input speed and an output speed, a transmission, and a clutch, the method comprising: in response to a driver tip-out during at least some conditions, decreasing powertrain output so that positive torque is not transmitted to the wheels;when said clutch is not transmitting torque and after said tip-out and in response to a driver tip-in, and at least during transitioning to transmission of positive powertrain torque to the wheels, retarding ignition timing while adjusting engine airflow until torque converter input speed is greater than torque converter output speed, and then advancing spark angle to rapidly provide output torque; andwhen transmitting at least some torque across the clutch and after said tip-out and in response to a driver tip-in, and at least during transitioning to transmission of positive powertrain torque to the wheels, retarding ignition timing while adjusting engine airflow, where said retarding and adjustment is different from that when said clutch is not transmitting torque, and then advancing spark angle to rapidly provide output torque.

13. The method of claim 11 wherein spark angle is further adjusted during at least one of said transition based on a gear ratio of the transmission.

14. The method of claim 13 wherein said difference may be a different ramping of spark timing.

15. The method of claim 13 wherein said difference may be a different ramping of throttle position.

16. The method of claim 12 wherein said clutch is a torque converter lock-up clutch.