Hybrid transmission and mode-shift control for hybrid vehicle

• US 20050023055A1
• Filed: 07/21/2004
• Published: 02/03/2005
• Est. Priority Date: 07/30/2003
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Mensler, Michel, Joe, Shinichiro, Imazu, Tomoya
• Granted Patent: US 7,306,064 B2
• Time in Patent Office: Days
• US Class Current: 180/65.235
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/11 using model predictive control [MPC] strategies, i.e. control methods based on models predicting performance utilising navigation and traffic information in the control strategy B60W20/12
• CPC Class Codes: B60W 20/40 Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers power-up or power-down of the driveline B60W30/192
• CPC Class Codes: F16H 2037/103 Power split variators with each end of the CVT connected or connectable to a Ravigneaux set
• CPC Class Codes: F16H 3/727 with at least two dynamo electric machines for creating an electric power path inside the gearing, e.g. using generator and motor for a variable power torque path special adapted for a hybrid electric vehicle B60K6/20
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/93 Conjoint control of different elements
• CPC Class Codes: Y10S 903/946 Characterized by control of driveline clutch

Abstract

A hybrid transmission for a hybrid vehicle mounting thereon an engine and a pair of electric motor/generators operates in a plurality of driving modes including EV mode in which the vehicle is powered by only the pair of motor/generators and EIVT mode in which the vehicle is powered by both the pair of motor/generators and the engine. The driving mode is shifted continuously and smoothly through a mode-shift transition process, in which the operating state is regulated to decrease the relative torque and/or the relative rotational speed between the contact elements of an engine clutch before engaging or disengaging the engine clutch.

Claims

1. A hybrid transmission for a hybrid vehicle mounting thereon a plurality of motors, comprising:

a differential mechanism including a plurality of rotating members, the number of which is one more than the number of the motors, each connected to a respective one of the motors and an drive train, for serving for determination of lever state in which driving power is shared among the motors;

sensors detecting the operating state of the hybrid vehicle;

a power regulator for regulating the output powers of the motors; and

a hybrid controller connected electrically to the sensors and the power regulator, and programmed to perform the following;

determining a current driving mode and a target driving mode based on the operating state of the hybrid vehicle;

determining a current lever state and a target lever state based on the operating state of the hybrid vehicle;

determining a mode-shift transition process from the current lever state in the current driving mode to the target lever state in the target driving mode, in which the lever state varies continuously and smoothly; and

executing the transition process with the power regulator.

2. The hybrid transmission as claimed in claim 1 further comprising a torque transmitting mechanism selectively connectable between one of the rotating members of the differential mechanism and an associated one of the motors and actuated by the power regulator, for serving for selection of driving mode, wherein the hybrid controller is programmed to perform the following:

reducing the relative rotational speed between the contact elements of the torque transmitting mechanism before engaging the torque transmitting mechanism if the mode-shift transition process includes a state shift of the torque transmitting mechanism from a disengaged state to an engaged state.

3. The hybrid transmission as claimed in claim 2, wherein the hybrid controller is programmed to perform the following:

shifting the engagement state of the torque transmitting mechanism from a disengaged state to an engaged state when the relative rotational speed between the contact elements of the torque transmitting mechanism is equal to or smaller than a predetermined threshold speed.

4. The hybrid transmission as claimed in claim 3, wherein the hybrid controller is programmed to perform the following:

reducing the relative rotational acceleration between the contact elements of the torque transmitting mechanism before engaging the torque transmitting mechanism.

5. The hybrid transmission as claimed in claim 1 further comprising a torque transmitting mechanism selectively connectable between one of the rotating members of the differential mechanism and an associated one of the motors and actuated by the power regulator, for serving for selection of driving mode, wherein the hybrid controller is programmed to perform the following:

decreasing torque transmitted between the contact elements of the torque transmitting mechanism before disengaging the torque transmitting mechanism if the mode shift transition process includes a state shift of the torque transmitting mechanism from an engaged state to a disengaged state.

6. The hybrid transmission as claimed in claim 5, wherein the hybrid controller is programmed to perform the following:

shifting the engagement state of the torque transmitting mechanism from a engaged state to an disengaged state when the transmitted torque between the contact elements of the torque transmitting mechanism is equal to or smaller than a predetermined threshold torque.

7. The hybrid transmission as claimed in claim 6, wherein the hybrid controller is programmed to perform the following:

reducing the rate of change of the transmitted torque before disengaging the torque transmitting mechanism.

8. The hybrid transmission as claimed in claim 1 further comprising a torque transmitting mechanism selectively connectable between one of the rotating members of the differential mechanism and an associated one of the motors and actuated by the power regulator, for serving for selection of driving mode, wherein the hybrid controller is programmed to perform the following:

reducing the relative rotational speed between the contact elements of the torque transmitting mechanism before engaging the torque transmitting mechanism if the mode-shift transition process includes a state shift of the torque transmitting mechanism from a disengaged state to an engaged state;

shifting the engagement state of the torque transmitting mechanism from a disengaged state to an engaged state when the relative rotational speed between the contact elements of the torque transmitting mechanism is equal to or smaller than a predetermined threshold speed;

reducing the relative rotational acceleration between the contact elements of the torque transmitting mechanism before engaging the torque transmitting mechanism;

decreasing torque transmitted between the contact elements of the torque transmitting mechanism before disengaging the torque transmitting mechanism if the mode shift transition process includes a state shift of the torque transmitting mechanism from an engaged state to a disengaged state;

shifting the engagement state of the torque transmitting mechanism from a engaged state to an disengaged state when the transmitted torque between the contact elements of the torque transmitting mechanism is equal to or smaller than a predetermined threshold torque; and

reducing the rate of change of the transmitted torque before disengaging the torque transmitting mechanism.

9. A hybrid transmission for a hybrid vehicle mounting thereon a plurality of motors, comprising:

differential means for including a plurality of rotating members, the number of which is one more than the number of the motors, each connected to a respective one of the motors and an drive train, for serving for determination of lever state in which driving power is shared among the motors;

sensing means for detecting the operating state of the hybrid vehicle;

power regulating means for regulating the output powers of the motors; and

control means for performing the following;

determining a current driving mode and a target driving mode based on the operating state of the hybrid vehicle;

determining a current lever state and a target lever state based on the operating state of the hybrid vehicle;

determining a mode-shift transition process from the current lever state in the current driving mode to the target lever state in the target driving mode, in which the lever state varies continuously and smoothly; and

executing the transition process with the power regulating means.

10. A method of controlling a hybrid transmission for a hybrid vehicle mounting thereon a plurality of motors, the method comprising:

determining a current driving mode and a target driving mode based on the operating state of the hybrid vehicle;

determining a current lever state and a target lever state based on the operating state of the hybrid vehicle;

determining a mode-shift transition process from the current lever state in the current driving mode to the target lever state in the target driving mode, in which the lever state varies continuously and smoothly; and

executing the transition process.

11. A method of controlling a hybrid transmission for a hybrid vehicle mounting thereon a plurality of motors, the hybrid transmission including a selectively connectable torque transmitting mechanism, the method comprising:

determining a current driving mode and a target driving mode based on the operating state of the hybrid vehicle;

determining a current lever state and a target lever state based on the operating state of the hybrid vehicle;

determining a mode-shift transition process from the current lever state in the current driving mode to the target lever state in the target driving mode, in which the lever state varies continuously and smoothly, the mode-shift transition process comprising reducing the relative rotational speed between the contact elements of the torque transmitting mechanism before engaging the torque transmitting mechanism if the mode-shift transition process includes a state shift of the torque transmitting mechanism from a disengaged state to an engaged state; and

executing the mode-shift transition process.

12. The method of controlling the hybrid transmission as claimed in claim 11, wherein the mode-shift transition process comprising:

shifting the engagement state of the torque transmitting mechanism from a disengaged state to an engaged state when the relative rotational speed between the contact elements of the torque transmitting mechanism is equal to or smaller than a predetermined threshold speed.

13. The method of controlling the hybrid transmission as claimed in claim 12, wherein the mode-shift transition process comprising:

reducing the relative rotational acceleration between the contact elements of the torque transmitting mechanism before engaging the torque transmitting mechanism.

14. A method of controlling a hybrid transmission for a hybrid vehicle mounting thereon a plurality of motors, the hybrid transmission including a selectively connectable torque transmitting mechanism, the method comprising:

determining a current driving mode and a target driving mode based on the operating state of the hybrid vehicle;

determining a current lever state and a target lever state based on the operating state of the hybrid vehicle;

determining a mode-shift transition process from the current lever state in the current driving mode to the target lever state in the target driving mode, in which the lever state varies continuously and smoothly, the mode-shift transition process comprising decreasing torque transmitted between the contact elements of the torque transmitting mechanism before disengaging the torque transmitting mechanism if the mode shift transition process includes a state shift of the torque transmitting mechanism from an engaged state to a disengaged state; and

executing the mode-shift transition process.

15. The method of controlling the hybrid transmission as claimed in claim 14, wherein the mode-shift transition process comprising:

shifting the engagement state of the torque transmitting mechanism from a engaged state to an disengaged state when the transmitted torque between the contact elements of the torque transmitting mechanism is equal to or smaller than a predetermined threshold torque.

16. The method of controlling the hybrid transmission as claimed in claim 15, wherein the mode-shift transition process comprising:

reducing the rate of change of the transmitted torque before disengaging the torque transmitting mechanism.