Parallel hybrid vehicle

• US 6,805,211 B2
• Filed: 09/23/2002
• Issued: 10/19/2004
• Est. Priority Date: 09/28/2001
• Status: Expired due to Fees

• Current Assignee: Jatco Limited (Nissan Motor Co., Ltd.)
• Original Assignee: Jatco Limited (Nissan Motor Co., Ltd.)
• Inventors: Fujikawa, Masato
• Primary Examiner(s): Ellis, Christopher P.
• Assistant Examiner(s): RESTIFO, JEFFREY J
• Application Number:
  US10/251,799
• Publication Number:
  US 20030062206A1
• Time in Patent Office: 757 Days
• Field of Search: 180/65.1, 180/65.2, 180/65.3, 180/65.4, 477/5, 477/6, 477/70, 477/22
• US Class Current: 180/65.25
• CPC Class Codes: B60K 6/383 One-way clutches or freewheel devices
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/54 Transmission for changing ratio
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/486 Operating parameters
• 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 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/18 including control of braking systems
• 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 20/40 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: B60W 2510/0604 Throttle position
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/081 Speed
• CPC Class Codes: B60W 2510/1005 Transmission ratio engaged
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 2710/02 Clutches
• CPC Class Codes: B60W 2710/105 : Output torque
• CPC Class Codes: B60W 2710/244 : Charge state
• CPC Class Codes: B60W 2720/106 : Longitudinal acceleration
• CPC Class Codes: F16H 3/724 : using external powered electric machines
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y10S 903/913 : One way
• CPC Class Codes: Y10S 903/917 : with transmission for changing gear ratio
• CPC Class Codes: Y10S 903/919 : Stepped shift
• CPC Class Codes: Y10S 903/945 : Characterized by control of gearing, e.g. control of transmission ratio
• CPC Class Codes: Y10S 903/946 : Characterized by control of driveline clutch
• CPC Class Codes: Y10S 903/947 : Characterized by control of braking, e.g. blending of regeneration, friction braking

Abstract

In a parallel hybrid vehicle, an revolution speed of an engine, a revolution speed of a motor/generator, and a regenerative power obtained by the motor/generator are calculated under both of released and clutched states of a lock-up clutch for each gear speed range achievable by a transmission on the basis of an estimated requested vehicular deceleration state and a driving state related to one of the gear speed ranges of the transmission and an operation state of the clutch is selected on the basis of the engine speed of the engine, the revolution speed of the motor/generator, and a regenerative power obtained by the motor/generator calculated as described above in such a manner that as a charge state of the charge device becomes smaller, the regenerative power obtained by means of the motor/generator becomes larger.

Claims

1. A hybrid vehicle, comprising:

an engine;

a charge device;

a transmission;

a motor/generator having both functions of

an electric motor and a generator and carrying out supply and receipt of an electric current to and from the charge device;

a differential unit having a first axle connected to an output axle of the engine, a second axle connected to an output axle of the motor/generator, and a third axle connected to an input axle of the transmission;

a clutch adapted to directly couple the engine and the motor/generator to be engaged when a difference in revolution speed between an engine speed of the engine and a revolution speed of the motor/generator becomes equal to or lower than a predetermined value during a start of the vehicle; and

a controlling section that enables control of an optimum state of the clutch, driving states of the motor/generator and the engine, and gear speed range of the transmission, the controlling section comprising;

requested deceleration state estimating section that estimates a requested vehicular deceleration state on the basis of at least one of a vehicular running speed and a brake manipulated variable of a vehicular brake system;

a calculating section that calculates the engine speed of the engine, the revolution speed of the motor/generator, and a regenerative power obtained by the motor/generator under both of released and clutched states of the clutch for each gear speed range achievable by the transmission on the basis of the requested vehicular deceleration state estimated by the requested deceleration state estimating section; and

an optimum driving state selecting section that selects one of the gear speed ranges of the transmission and an operation state of the clutch on the basis of the engine speed of the engine, the revolution speed of the motor/generator, and the regenerative power obtained by the motor/generator calculated by the calculating section in such a manner that as a charge state of the charge device becomes smaller, the regenerative power obtained by the motor/generator becomes larger, wherein the controlling section is adapted to control the operation state of the clutch, the driving states of the engine and motor/generator, and the gear speed range of the transmission on the basis of the gear speed range of the transmission and the clutched state of the clutch related to the driving state selected by the optimum driving state selecting section.

2. A hybrid vehicle as claimed in claim 1, wherein the hybrid vehicle comprises an accelerator manipulated variable detecting section that detects a manipulated variable of a vehicular accelerator;

a vehicular velocity detecting section that detects a running speed of the vehicle; and

a brake pedal depression depth detecting section that detects a depression depth of the brake pedal and wherein the requested deceleration state estimating section estimates the requested vehicular deceleration state on the basis of at least one of the vehicular running speed and the brake manipulated variable detected by the accelerator manipulated variable detecting section and at least one of the vehicular velocity detecting section and the brake pedal depression depth detecting section.

3. A hybrid vehicle as claimed in claim 1, wherein the hybrid vehicle comprises a throttle opening angle detecting section that detects an opening angle of an engine throttle valve and the requested deceleration state estimating section comprises a requested deceleration state determining section that determines whether the opening angle of the engine throttle valve is zeroed to determine whether a request of the vehicular deceleration occurs.

4. A hybrid vehicle as claimed in claim 3, wherein the hybrid vehicle comprises a clutch state determining section that determines whether the clutch is in the clutched state or in the released state;

and a target deceleration calculating section that calculates a target torque T_PS* of a propeller shaft according to the running speed of the vehicle and according to a brake liquid pressure of the vehicular brake system when the clutch state determining section determines that the clutch is in the clutched state.

5. A hybrid vehicle as claimed in claim 4, wherein the calculating section calculates the engine speed, an engine torque, a motor/generator torque, the motor/generator speed, and the regenerative power with a clutch engaged state maintained for each gear speed range of the transmission when the clutch state determining section determines that the clutch is in the clutched state.

6. A hybrid vehicle as claimed in claim 4, wherein the calculating section calculates the engine speed, an engine torque, a motor/generator torque, the motor/generator speed, and the regenerative power when the clutch is in a clutch released state for each gear speed range of the transmission when the clutch state determining section determines that the clutch is in the clutched state.

7. A hybrid vehicle as claimed in claim 4, wherein the target deceleration calculating section calculates the target torque T_PS* of the propeller shaft in such a manner that as the vehicular running speed is increased, the target torque T_PS* of the propeller shaft becomes larger in a negative direction and in such a manner that as the brake liquid pressure of the vehicular brake system becomes increased, the target torque T_PS* becomes larger in the negative direction.

8. A hybrid vehicle as claimed in claim 7, wherein the controlling section further comprises a correction coefficient determining section that determines a correction factor for the target torque T_PS* of the propeller shaft in such a manner that as the charge quantity of the charge device becomes remarkably smaller, the correction factor becomes larger than one and as a charge quantity of the charge device becomes remarkably larger, the correction factor becomes smaller than one, the correction factor being multiplied with the target torque of the propeller shaft to determine a final target torque T_PS* of the propeller shaft.

9. A hybrid vehicle as claimed in claim 1, wherein the hybrid vehicle comprises a charge quantity detecting section that detects a charge quantity in the charge device and wherein the optimum driving state selecting section comprises:

a first charge state determining section that determines whether the charge quantity in the charge device is equal to or lower than a first predetermined value;

a first driving state selecting section that selects one of a plurality of driving states in which the regenerative power is the largest when the first charge state determining section determines that the charge quantity is equal to or lower than the first predetermined value; and

an allowance condition determining section that determines whether the selected driving state by the first driving state selecting section satisfies at least one allowance condition and wherein the controlling section controls the operation state of the clutch, the driving states of the engine and motor/generator, and the gear speed range of the transmission on the basis of the gear speed range of the transmission and the clutched state of the clutch related to one of the driving states which is selected by the first driving state selecting section when the allowance condition determining section determines that the selected driving state satisfies at least one allowance condition.

10. A hybrid vehicle as claimed in claim 9, wherein the optimum driving state selecting section comprises:

a second charge state determining section that determines whether the charge quantity in the charge device is higher than the first predetermined value but is equal to or lower than a second predetermined value;

a second driving state selecting section that selects one of the driving states in which the regenerative power is the largest with the gear speed range of the transmission maintained when the second charge state determining section determines that the charge quantity is higher the first predetermined value but is equal to or lower than the second predetermined value; and

another allowance condition determining section that determines whether the driving state selected by the second driving state selecting section satisfies at least one allowance condition and wherein the controlling section controls the operation state of the clutch, the driving states of the engine and motor/generator, and the gear speed range of the transmission on the basis of the gear speed range of the transmission and the operation state of the clutch related to one of the driving states selected by the second driving state selecting section when the other allowance condition determining section determines that the driving state selected by the second driving state selecting section satisfies at least one allowance condition.

11. A hybrid vehicle as claimed in claim 10, wherein the first predetermined value is a value of the charge quantity to be charged in the charge device having a predetermined high priority and the second predetermined value is a value of the charge quantity that the charge device is in no need of being charged.

12. A hybrid vehicle as claimed in claim 10, wherein the allowance condition includes an engine speed of the engine N_E which is equal to or higher than an engine idling speed but is lower than a maximum speed limit value thereof, a revolution speed N_M/G of the motor/generator which is equal to or higher than zero but is equal to or lower than a maximum revolution speed thereof, and a motor/generator torque T_M/G is equal to or higher than zero but is equal to or lower than a maximum torque thereof.

13. A hybrid vehicle as claimed in claim 1, wherein the hybrid vehicle is adapted to regenerate the charge device without need of a clutch which cuts off power between the engine and the differential unit.

14. A hybrid vehicle, comprising:

an engine;

a charge device;

a transmission;

a motor/generator having both functions of

an electric motor and a generator and carrying out supply and receipt of an electric current to and from the charge device;

a differential unit having a first axle connected to an output axle of the engine, a second axle connected to an output axle of the motor/generator, and a third axle connected to an input axle of the transmission;

a clutch adapted to directly couple the engine and the motor/generator to be engaged when a difference in revolution speed between an engine speed of the engine and a revolution speed of the motor/generator becomes equal to or lower than a predetermined value during a start of the vehicle; and

controlling means for enabling controls of an optimum state of the clutch, driving states of the motor/generator and the engine, and gear speed range of the transmission, the controlling means comprising;

requested deceleration state estimating means for estimating a requested vehicular deceleration state on the basis of at least one of a vehicular running speed and a brake manipulated variable of a vehicular brake system;

calculating means for calculating the engine speed of the engine, the revolution speed of the motor/generator, and a regenerative power obtained by the motor/generator under both of released and clutched states of the clutch for each gear speed range achievable by the transmission on the basis of the requested vehicular deceleration state estimated by the requested deceleration state estimating means; and

optimum driving state selecting means for selecting one of the gear speed ranges of the transmission and an operation state of the clutch on the basis of the engine speed of the engine, the revolution speed of the motor/generator, and the regenerative power obtained by the motor/generator calculated by the calculating means in such a manner that as a charge state of the charge device becomes smaller, the regenerative power obtained by means of the motor/generator becomes larger, wherein the controlling means is adapted to control the operation state of the clutch, the driving states of the engine and motor/generator, and the gear speed range of the transmission on the basis of the gear speed range of the transmission and the clutched state of the clutch related to the driving state selected by the optimum driving state selecting means.

15. A method applicable to a hybrid vehicle, comprising utilizing components of a hybrid vehicle, the components of the hybrid vehicle comprising:

an engine;

a charge device;

a transmission;

a motor/generator having both functions of

an electric motor and a generator and carrying out supply and receipt of an electric current to and from the charge device;

a differential unit having a first axle connected to an output axle of the engine, a second axle connected to an output axle of the motor/generator, and a third axle connected to an input axle of the transmission;

a clutch adapted to directly couple the engine and the motor/generator to be engaged when a difference in revolution speed between an engine speed of the engine and a revolution speed of the motor/generator becomes equal to or lower than a predetermined value during a start of the vehicle; and

a controlling section that enables control of an optimum state of the clutch, driving states of the motor/generator and the engine, and gear speed range of the transmission, the method further comprising;

estimating a requested vehicular deceleration state on the basis of at least one of a vehicular running speed and a brake manipulated variable of a vehicular brake system;

calculating the engine speed of the engine, the revolution speed of the motor/generator, and a regenerative power obtained by the motor/generator under both of released and clutched states of the clutch for each gear speed range achievable by the transmission on the basis of the estimated requested vehicular deceleration state; and

selecting one of the gear speed ranges of the transmission and an operation state of the clutch on the basis of the engine speed of the engine, the revolution speed of the motor/generator, and the regenerative power obtained by the motor/generator calculated in such a manner that as a charge state of the charge device becomes smaller, the regenerative power obtained by by the motor/generator becomes larger, wherein, at the controlling step, the operation state of the clutch, the driving states of the engine and motor/generator, and the gear speed range of the transmission are controlled on the basis of the gear speed range of the transmission and the clutched state of the clutch related to the selected driving state.