Method for controlling a driveline in order to optimize fuel consumption

• US 10,207,701 B2
• Filed: 03/17/2015
• Issued: 02/19/2019
• Est. Priority Date: 03/20/2014
• Status: Active Grant

• Current Assignee: Scania CV AB (Volkswagen AG)
• Original Assignee: Scania CV AB (Volkswagen AG)
• Inventors: Bjorkman, Mathias, Pettersson, Niklas, Lindstrom, Johan, Bergquist, Mikael
• Primary Examiner(s): Pang, Roger L
• Application Number:
  US15/124,125
• Publication Number:
  US 20170015303A1
• Time in Patent Office: 1,435 Days
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/405 Housings
• CPC Class Codes: B60K 6/442 Series-parallel switching type
• 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 10/115 with planetary gears
• CPC Class Codes: B60W 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• 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 2710/0644 Engine speed
• CPC Class Codes: B60W 2710/105 Output torque
• CPC Class Codes: B60Y 2200/92 Hybrid vehicles
• CPC Class Codes: B60Y 2300/188 Controlling power parameters of the driveline, e.g. determining the required power
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/91 Orbital, e.g. planetary gears
• 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

Abstract

A method is provided to start a hybrid powertrain to optimize fuel consumption, wherein such hybrid powertrain comprises a combustion engine; a gearbox with input shaft and output shaft; a first planetary gear, connected to the input shaft and a first main shaft; a second planetary gear, connected to the first planetary gear and a second main shaft; first and second electrical machines respectively, connected to the first and second planetary gears; one gear pair connected with the first main shaft; and one gear pair connected with the second main shaft. The method comprising: ensuring that the moveable parts of each of the first and second planetary gears are respectively disconnected from each other; bringing the combustion engine to a predetermined engine speed (n_ice); and controlling the first and the second electrical machine in such a way that a desired torque (T_Drv) is achieved in the output shaft.

Claims

1. A method to control a hybrid powertrain to optimize fuel consumption, wherein such hybrid powertrain comprises a combustion engine;

a gearbox with an input shaft and an output shaft;

a first planetary gear, connected to the input shaft and a first main shaft;

a second planetary gear, connected to the first planetary gear and a second main shaft;

a first electrical machine, connected to the first planetary gear;

a second electrical machine, connected to the second planetary gear;

at least one gear pair connected with the first main shaft, and therefore the first planetary gear and the output shaft; and

at least one gear pair connected with the second main shaft, and therefore with the second planetary gear and the output shaft, wherein the combustion engine is connected with a first planetary wheel carrier, arranged in the first planetary gear via the input shaft of the gearbox, and wherein the second main shaft is connected with a planetary wheel carrier, arranged in the second planetary gear, said method comprising the steps;

a) ensuring that moveable parts comprised in the first planetary gear are disconnected from each other, and that moveable parts comprised in the second planetary gear are disconnected from each other;

b) bringing the combustion engine to a predetermined engine speed; and

c) controlling the first and the second electrical machine in such a way that a desired torque is achieved in the output shaft.

2. A method according to claim 1, wherein in step a) the first and/or the second electrical machine is controlled in such a way that torque balance is achieved in the first planetary gear, following which a first coupling device is shifted, so that the first planetary wheel carrier and a first sun wheel are disconnected from each other.

3. A method according to claim 1, wherein in step a) the first and/or the second electrical machine is controlled in such a way that torque balance is achieved in the second planetary gear, following which a second coupling device is shifted, so that the second planetary wheel carrier and a second sun wheel are disconnected from each other.

4. A method according to claim 1, wherein the predetermined engine speed in step b) substantially corresponds to the combustion engine'"'"'s idling engine speed.

5. A method according to claim 1, wherein the predetermined engine speed in step b) is between 300 and 700 revolutions/minute.

6. A method according to claim 1, wherein the torque desired in the output shaft in step c) is a positive torque.

7. A method according to claim 6, wherein in step c) the first and the second electrical machines are controlled based on a determined requested total power consumption of the first and the second electrical machine.

8. A method according to claim 1, wherein the torque desired in the output shaft in step c) is a negative torque.

9. A method according to claim 8, wherein in step c) the first and the second electrical machines are controlled based on a torque acting on the combustion engine.

10. A method according to claim 9, wherein the torque, which acts on the combustion engine, is determined by a speed governor.

11. A vehicle with a hybrid powertrain, said hybrid powertrain comprising:

a combustion engine;

a gearbox with an input shaft and an output shaft;

a first planetary gear, connected to the input shaft and a first main shaft;

a second planetary gear, connected to the first planetary gear and a second main shaft;

a first electrical machine, connected to the first planetary gear;

a second electrical machine, connected to the second planetary gear;

at least one gear pair connected with the first main shaft, and therefore with the first planetary gear and the output shaft;

at least one gear pair connected with the second main shaft, and therefore with the second planetary gear and the output shaft, wherein the combustion engine is connected with a first planetary wheel carrier, arranged in the first planetary gear via the input shaft of the gearbox, and wherein the second main shaft is connected with a second planetary wheel carrier, arranged in the second planetary gear; and

an electronic control device configured for;

a) ensuring that moveable parts comprised in the first planetary gear are disconnected from each other, and that moveable parts comprised in the second planetary gear are disconnected from each other;

b) bringing the combustion engine to a predetermined engine speed; and

c) controlling the first and the second electrical machine in such a way that a desired torque is achieved in the output shaft.

12. A computer program product comprising computer program code stored on a non-transitory computer readable medium readable by a computer, said computer program product used to optimize fuel consumption, wherein such hybrid powertrain comprises a combustion engine;

a gearbox with an input shaft and an output shaft;

a first planetary gear, connected to the input shaft and a first main shaft;

a second planetary gear, connected to the first planetary gear and a second main shaft;

a first electrical machine, connected to the first planetary gear;

a second electrical machine, connected to the second planetary gear;

at least one gear pair connected with the first main shaft, and therefore the first planetary gear and the output shaft; and

at least one gear pair connected with the second main shaft, and therefore with the second planetary gear and the output shaft, wherein the combustion engine is connected with a first planetary wheel carrier, arranged in the first planetary gear via the input shaft of the gearbox, and wherein the second main shaft is connected with a planetary wheel carrier, arranged in the second planetary gear,

said computer program code comprising computer instructions to cause one or more computer processors to perform the operations of;

a) ensuring that moveable parts comprised in the first planetary gear are disconnected from each other, and that moveable parts comprised in the second planetary gear are disconnected from each other;

b) bringing the combustion engine to a predetermined engine speed; and

c) controlling the first and the second electrical machine in such a way that a desired torque is achieved in the output shaft.