Powertrain control device for a vehicle using targeted tongue generation for eliminating shift shock

• US 5,826,208 A
• Filed: 10/26/1995
• Issued: 10/20/1998
• Est. Priority Date: 10/26/1994
• Status: Expired due to Fees

• Current Assignee: Hitachi Car Engineering Company Limited (Hitachi, Ltd.), Hitachi, Ltd.
• Original Assignee: Hitachi Car Engineering Company Limited (Hitachi, Ltd.), Hitachi, Ltd.
• Inventors: Sato, Kazuhiko, Ibamoto, Masahiko, Kuroiwa, Hiroshi, Shida, Masami, Okada, Mitsuyoshi
• Primary Examiner(s): Zanelli, Michael
• Assistant Examiner(s): Pipala, Edward J.
• Application Number:
  US08/548,470
• Time in Patent Office: 1,090 Days
• Field of Search: 364/424.082, 364/424.083, 364/424.087, 364/424.089, 364/431.051, 477/107, 477/109, 477/110, 477/115, 477/129, 477/156, 701/53, 701/54, 701/55, 701/56, 701/58, 701/60, 701/64, 701/66
• US Class Current: 701/54
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 2050/0031 Mathematical model of the vehicle
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 30/1819 Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: B60W 30/19 Improvement of gear change, e.g. by synchronisation or smoothing gear shift
• CPC Class Codes: F16H 61/0021 Generation or control of line pressure
• CPC Class Codes: F16H 63/502 for smoothing gear shifts
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

The object of this invention is to reduce shift shocks by controlling the driving torque during gear shift changing so that the driving torque is represented by a smooth, ideal waveform. The driving torque calculating means estimates the output shaft torque of the automatic transmission from the engine torque characteristic or torque converter characteristic and, based on the estimated driving torque, generate a targeted torque pattern during gear shift changing. The engine torque control value calculating means calculates the control value for controlling the engine output torque, i.e., an ignition timing correction value Δθig, so as to eliminate the deviation between the targeted torque and the driving torque estimated by the driving torque calculating means. This ignition timing correction approximates the driving torque to smooth the targeted torque.

Claims

1. A powertrain control device for a vehicle comprising:

an automatic transmission having a torque converter;

a control device incorporating at least one microcomputer to control the engine and the automatic transmission;

a driving torque calculating means for estimating the output shaft torque of the automatic transmission;

a targeted torque generating means for generating a targeted torque based on the driving torque estimated by the driving torque calculating means;

an engine torque control value calculating means for calculating a control value for controlling the output torque of the engine from the deviation between the targeted torque generated by the targeted torque generating means and the driving torque estimated by the driving torque calculating means;

an engine torque control value limiting means provided in the engine torque control value calculating means, for limiting the engine torque control value below a specified value;

an engine torque control means for controlling the output torque of the engine in response to a signal from the engine torque control value calculating means;

an estimated driving torque monitoring means for monitoring the magnitude of the estimated driving torque calculated by the driving torque calculating means; and

a line pressure control device for controlling a line pressure of the automatic transmission by use of the estimated driving torque monitoring means.

2. A powertrain control device according to claim 1, wherein when the estimated driving torque monitoring means decides that the line pressure of the automatic transmission is greater than a predetermined value, the line pressure control device controls the line pressure so that it is reduced by a specified value.

3. A powertrain control device according to claim 1, wherein when the estimated driving torque monitoring means judges that the line pressure of the automatic transmission is smaller than a predetermined value, the line pressure control device controls the line pressure so that it is increased by a specified value.

4. A powertrain control device according to claim 1, wherein the line pressure control device has a means for learning the line pressure at gear shift changing for selectively controlling the estimated output shaft torque estimated by the driving torque calculating means.

5. A powertrain control device for a vehicle comprising:

an automatic transmission having a torque converter;

a control device incorporating at least one microcomputer to control the engine and the automatic transmission;

a driving torque calculating means for estimating the output shaft torque of the automatic transmission;

a targeted torque generating means for generating a targeted torque based on the driving torque estimated by the driving torque calculating means;

an engine torque control value calculating means for calculating a control value for controlling the output torque of the engine from the deviation between the target torque generated by the target torque generating means and the driving torque estimated by the driving torque calculating means;

an engine torque control value limiting means provided in the engine torque control value calculating means, for limiting the engine torque control value above a specified value;

an engine torque control means for controlling the output torque of the engine in response to a signal from the engine torque control value calculating means;

a static line pressure determining means for determining line pressure of the automatic transmission during the normal traveling;

an estimated driving torque monitoring means for monitoring the magnitude of the estimated driving torque calculated by the driving torque calculating means;

a selecting means for selecting either the static line pressure determining means or the estimated driving torque monitoring means; and

a line pressure control device for controlling the line pressure of the automatic transmission according to the output from the selecting means.

6. A powertrain control device according to claim 5, wherein the engine torque control means changes the engine ignition timing correction value.

7. A powertrain control device according to claim 6, wherein the engine torque control value limiting means limits the engine ignition timing correction value so that the engine ignition timing correction value exceeds a predetermined value.

8. A powertrain control device for a vehicle comprising:

an engine;

an automatic transmission having a torque converter;

a control device incorporating at least one microcomputer for controlling the engine and the automatic transmission;

a driving torque calculating means for estimating the output shaft torque of the automatic transmission;

a targeted torque generating means for generating a targeted torque during gear shift changing based on the driving torque estimated by the driving torque calculating means;

an engine torque control value calculating means for calculating a control value used for controlling the output torque of the engine to eliminate the deviation between the targeted torque generated by the targeted torque generating means and the driving torque estimated by the driving torque calculating means; and

an engine torque control means for controlling the output torque of the engine in response to a signal from the engine torque control value calculating means.

9. A powertrain control device according to claim 8, wherein the driving torque calculating means includes a turbine torque calculating means for estimating the turbine torque, and the targeted torque generating means recognizes, as an actual gear shift changing timing, the time when the estimated turbine torque determined by the turbine torque calculating means in the driving torque calculating means becomes greater than a predetermined value with a predetermined time period after a shift command, temporarily stores, as a driving torque before gear shift changing, the driving torque at the actual gear shift changing timing or an average driving torque immediately before it, calculates the driving torque after the gear shift changing from the driving torque before the gear shift changing and the gear ratio before and after the gear shift changing, calculates the difference between the driving torques before and after the gear shift changing and an inclination angle with elapsed time of the targeted torque from a present gear shift changing time, and calculates the targeted torque according to the inclination angle every predetermined calculating cycle.

10. A powertrain control device according to claim 8, wherein the engine torque control value calculating means includes a means for calculating the deviation between the targeted torque value generated by the targeted torque generating means every predetermined calculation cycle and the driving torque value calculated by the driving torque calculating means, and an engine torque control value conversion means for calculating an engine torque control value by multiplying the deviation calculated by the deviation calculating means by a preset and stored conversion coefficient.

11. A powertrain control device according to claim 10, wherein the conversion coefficient is set to zero when the driving torque value is smaller than the targeted torque value with a first predetermined period from the actual gear shift changing timing;

the conversion coefficient is set to a predetermined characteristic value when the driving torque value is greater than the targeted torque value within a second predetermined period, longer than the first period, after the actual gear shift changing timing; and

within a period after the second predetermined period it is set to a value determined by dividing the predetermined characteristic value by the coefficient of the elapsed time.

12. A powertrain control device according to claim 8, wherein the driving torque calculating means includes a first driving torque calculating means for estimating the driving torque by using a prestored engine torque characteristic, a second driving torque by using a prestored torque converter characteristic, and a selecting means for selecting either the first of second driving torque calculating means in such a way that the second driving torque calculating means is used in a region where the torque converter slip is judged to be large and the first driving torque calculating means is used in a region where the torque converter slip is judged to be small so as to estimate the output shaft torque of the automatic transmission.

13. A powertrain control device according to claim 12, further comprising an accessory device torque learning means for learning and storing as a load torque of the engine accessory devices the deviation between the torques estimated by the first and second driving torque calculating means immediately before the selecting means switches from the second driving torque calculating means to the first driving torque calculating means, and after the switch from the second to the first driving torque calculating means, subtracts the accessory device torque stored in the accessory device torque learning means from the estimated torque given by the first driving torque calculating means to correct the load torque of the accessory devices.

14. A powertrain control device according to claim 12, wherein the first driving torque calculating means for estimating the driving torque by using the engine torque characteristic includes:

an engine torque characteristic memory means for storing the engine torque characteristic beforehand;

a means for calculating the slip ratio of the torque converter;

a means for calculating the torque ratio of the torque converter based on the slip ratio information from the slip ratio calculating means;

a turbine torque calculating means for calculating the output shaft torque of the torque converter by multiplying the engine torque read from the engine torque characteristic memory means by the torque ratio output from the torque ratio calculating means; and

an automatic transmission output shaft torque calculating means for calculating the output shaft torque of the automatic transmission by multiplying the output shaft torque of the torque converter from the turbine torque calculating means by the gear ratio of the current gear position.

15. A powertrain control device according to claim 14, wherein the engine torque characteristic memory means stores the engine torque using the accelerator pedal opening or a throttle valve opening and the engine rotation speed as parameters.

16. A powertrain control device according to claim 14, wherein the engine torque characteristic memory means stores the engine torque using the intake air mass flow and the engine rotation speed as parameters.

17. A powertrain control device according to claim 16, wherein the engine torque characteristic memory means includes a means for calculating the intake air mass flow from the intake air pressure and the intake air temperature.

18. A powertrain control device according to claim 14, wherein the engine torque characteristic memory means stores the engine torque using the intake air pressure, the intake air temperature and the engine rotation speed as parameters.

19. A powertrain control device according to claim 14, wherein the engine torque characteristic memory means stores the engine torque using the pulse width for operating the fuel injector and an engine rotation speed as parameters.

20. A powertrain control device according to claim 12, wherein the second driving torque calculating means for estimating the driving torque by using the torque converter characteristic includes:

an input capacity coefficient characteristic memory means for storing the characteristics of the input capacity coefficient from the torque converter beforehand;

a means for calculating the slip ratio of the torque converter;

a means to calculate a torque ratio of the torque converter based on the slip ratio information from the slip ratio calculating means;

a torque converter input torque calculating means for calculating the input torque of the torque converter by multiplying the input capacity coefficient read from the input capacity coefficient characteristic memory means by a squared engine rotation speed signal from an engine rotation speed squaring means;

a turbine torque calculating means for calculating the output shaft torque of the torque converter by multiplying the torque ratio from the torque ratio calculating means by the input torque of the torque converter from the torque converter input torque calculating means, and outputting the output shaft torque of the torque converter; and

an automatic transmission output shaft torque calculating means for calculating the output shaft torque of the automatic transmission by multiplying the output shaft torque of the torque converter from the turbine torque calculating means by the gear ratio of the current gear position, and outputting the output shaft torque of the automatic transmission.

21. A powertrain control device for a vehicle having an engine, an automatic transmission, a torque converter, a transmission change signal generator for generating a transmission change signal at a transmission change timing, and a line pressure control device for controlling a line pressure of the automatic transmission, comprising:

at least one microcomputer to control the engine and the automatic transmission, wherein the powertrain control device has functions as follows;

(a) calculating a present output shaft torque of the automatic transmission;

(b) calculating a targeted torque based on the calculated present output shaft torque at a predetermined time after generating the transmission change signal;

(c) calculating an engine control value for controlling the output torque of the engine such that a deviation between the targeted torque and the present output shaft torque is reduced;

(d) calculating a line pressure control value for controlling the line pressure at the predetermined time based on the calculated present output shaft torque; and

(e) outputting an engine control signal for controlling the engine based on the calculated engine control value and a line pressure control signal for controlling the line pressure based on the calculated line pressure control value.

22. A powertrain control device according to claim 21, wherein the targeted torque is the same value as the present output shaft torque at the predetermined time after the transmission change signal.

23. A powertrain control device according to claim 21, wherein when the targeted torque reduces at a predetermined rate starting from the present output shaft torque at the predetermined time after the transmission change signal.

24. A powertrain control device according to claim 21, wherein the line pressure control value is decided based on a deviation between the present output shaft torque and a predetermined value which is calculated during a transmission change the last time.