HYBRID VEHICLE AND CONTROL METHOD FOR HYBRID VEHICLE

• US 20140343775A1
• Filed: 05/15/2014
• Published: 11/20/2014
• Est. Priority Date: 05/17/2013
• Status: Active Grant

• Current Assignee: Aisin AW Company Limited (Aisin Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Aisin AW Company Limited (Aisin Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: YAMAMOTO, Masaya, KATO, Shunya, KIMURA, Akihiro, FURUTA, Hideki
• Granted Patent: US 9,487,210 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• 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: B60K 6/547 the transmission being a stepped gearing
• 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 10/115 with planetary gears
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/30 Control strategies involving selection of transmission gear ratio control of change speed gearings, together with other vehicle sub-units B60W10/10; HEV transmission gearing B60K6/36; gearings and control thereof F16H
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2710/0661 Speed change rate
• CPC Class Codes: B60W 2710/082 Speed change rate
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 2710/248 Current for loading or unloading
• CPC Class Codes: B60W 30/19 Improvement of gear change, e.g. by synchronisation or smoothing gear shift
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/93 Conjoint control of different elements

Abstract

A hybrid vehicle includes a differential device, a first motor, an engine, a second motor, an engagement device, and an electronic control unit. The electronic control unit is configured to control the first motor and the second motor when an engagement state of the engagement device changes, such that a first angular acceleration and a second angular acceleration reach a first target value and the second target value respectively, the first angular acceleration and the second angular acceleration being two angular accelerations of the engine, the first motor, and the second motor and to calculate the first target value and the second target value by applying a constraint condition to at least one of the first target value and the second target value.

Claims

1. A hybrid vehicle comprising:

a differential device constituted with a first rotating element, a second rotating element, and a third rotating element;

a first motor coupled to the first rotating element;

an engine coupled to the second rotating element;

a second motor coupled to a power transmission path between the third rotating element and a drive shaft;

an engagement device disposed in the power transmission path and configured to change a power transmission state between the differential device and the drive shaft; and

an electronic control unit configured to;

(a) control the first motor and the second motor when an engagement state of the engagement device changes, such that a first angular acceleration and a second angular acceleration reach a first target value and a second target value respectively, the first angular acceleration and the second angular acceleration being two angular accelerations of the engine, the first motor, and the second motor; and

(b) calculate the first target value and the second target value by applying a constraint condition to at least one of the first target value and the second target value.

2. The hybrid vehicle according to claim 1, wherein

the electronic control unit is configured to correct the first target value and the second target value such that the first target value and the second target value satisfy the constraint condition when the first target value and the second target value do not satisfy the constraint condition.

3. The hybrid vehicle according to claim 1, wherein

the first angular acceleration is the angular acceleration of the engine, and

the second angular acceleration is the angular acceleration of the second motor.

4. The hybrid vehicle according to claim 3, wherein

an upper limit and a lower limit are set to each torque of the first motor and the second motor, and

the electronic control unit is configured to set the constraint condition by performing coordinate transformations of the upper limit and the lower limit of the torque into an angular acceleration plane where the first angular acceleration and the second angular acceleration are variables.

5. The hybrid vehicle according to claim 3, further comprising:

an electric storage device configured to supply and receive electric power to and from the first motor and the second motor;

wherein the electronic control unit is configured to set the constraint condition by performing coordinate transformations of dischargeable electric power and chargeable electric power into an angular acceleration plane where the first angular acceleration and the second angular acceleration are variables, the dischargeable electric power being a upper limit of the discharging electric power of the electric storage device, and the chargeable electric power being a upper limit of the charging electric power of the electric storage device.

6. The hybrid vehicle according to claim 3, wherein

the constraint condition is set to the first target value such that a speed of the engine does not exceed a predetermined upper limit and lower limit.

7. The hybrid vehicle according to claim 3, wherein the engagement device includes a transmission, and the constraint condition is set to the second target value such that gear shift of the transmission proceeds.

8. The hybrid vehicle according to claim 3, wherein

the constraint condition is set to the first target value such that a speed of the engine indicates predetermined behavior when the engagement state of the engagement device changes.

9. The hybrid vehicle according to claim 3, further comprising:

an electric storage device configured to supply and receive electric power to and from the first motor and the second motor;

wherein

an upper limit and a lower limit are set to a torque of the first motor and the second motor,

the engagement device includes a transmission,

the constraint condition includes a first condition, a second condition, a third condition, and a fourth condition,

the electronic control unit is configured to apply the constraint condition to the first target value and the second target value in the order of the first condition, the second condition, the third condition, and the fourth condition,

the first condition is set to the first target value such that a speed of the engine indicates predetermined behavior when the engagement state of the engagement device changes,

the second condition is set to the second target value such that gear shift of the transmission proceeds,

the third condition includes at least one of

(i) a condition that is set by performing coordinate transformations of dischargeable electric power and chargeable electric power into an angular acceleration plane where the first angular acceleration and the second angular acceleration are variables, the dischargeable electric power being a upper limit of the discharging electric power of the electric storage device, and the chargeable electric power being a upper limit of the charging electric power of the electric storage device, and

(ii) a condition that is set to the first target value such that the speed of the engine does not exceed a specified upper limit and lower limit, and

the fourth condition is set by performing the coordinate transformations of the upper limit and the lower limit of the torque of the first motor and the second motor into the angular acceleration plane.

10. The hybrid vehicle according to claim 3, wherein

the electronic control unit is configured to calculate a first torque and a second torque based on the first target value and the second target value to which the constraint condition is applied by using a model of the differential device expressing a relation among the first angular acceleration, the second angular acceleration, the first torque and the second torque respectively representing the torque of the first motor and the second motor, the torque of the engine, and torque capacity of the engagement device, and

the electronic control unit is configured to control the first motor and the second motor so as to respectively output the first torque and the second torque.

11. The hybrid vehicle according to claim 10, wherein

the electronic control unit is configured to estimate the torque capacity based on the angular accelerations of the first motor and the second motor by using the model, and

the electronic control unit is configured to calculate the first torque and the second torque by using the estimated torque capacity.

12. The hybrid vehicle according to claim 11, wherein

the electronic control unit is configured to estimate the torque of the engine based on the angular accelerations of the first motor and the second motor by using the model, and

the electronic control unit is configured to calculate the first torque and the second torque by using the estimated torque of the engine.

13. The hybrid vehicle according to claim 11, wherein

the electronic control unit is configured to perform low-pass filter processing to measured values of speeds of the first motor and the second motor, and

the electronic control unit is configured to calculate the angular accelerations of the first motor and the second motor based on the measured values to which the low-pass filter processing is performed.

14. The hybrid vehicle according to claim 13, wherein

the electronic control unit is configured to change a time constant in the low-pass filter processing depending on driving conditions of the hybrid vehicle.

15. The hybrid vehicle according to claim 1, wherein

the engagement device includes a transmission, and

the transmission is disposed in a power transmission path between the second motor and the drive shaft.

16. A hybrid vehicle comprising:

a differential device constituted with a first rotating element, a second rotating element, and a third rotating element;

a first motor coupled to the first rotating element;

an engine coupled to the second rotating element;

a second motor coupled to a power transmission path between the third rotating element and a drive shaft;

an engagement device disposed in the power transmission path and configured to change a power transmission state between the differential device and the drive shaft; and

an electronic control unit configured to;

(a) control the first motor and the second motor when an engagement state of the engagement device changes, such that a first angular acceleration and a second angular acceleration reach a first target value and a second target value respectively, the first angular acceleration and the second angular acceleration being two angular accelerations of the engine, the first motor, and the second motor; and

(b) correct the first target value and the second target value such that the first target value and the second target value satisfy a constraint condition, when the first target value and the second target value do not satisfy the constraint condition.

17. A control method for a hybrid vehicle including a differential device constituted with a first rotating element, a second rotating element, and a third rotating element, a first motor coupled to the first rotating element, an engine coupled to the second rotating element, a second motor coupled to a power transmission path between the third rotating element and a drive shaft, an engagement device disposed in the power transmission path and configured to change a power transmission state between the differential device and the drive shaft, and an electronic control unit,

the control method comprising:

(a) controlling the first motor and the second motor by the electronic control unit when an engagement state of the engagement device changes, such that a first angular acceleration and a second angular acceleration reach a first target value and a second target value respectively, the first angular acceleration and the second angular acceleration being two angular accelerations of the engine, the first motor, and the second motor; and

(b) calculating, by the electronic control unit, the first target value and the second target value by applying a constraint condition to at least one of the first target value and the second target value.