Method for driving a hybrid vehicle in connection with start of the combustion engine of the vehicle

Patent metadata

Field	Value
Publication number	US-9527504-B2
Application number	US-201314410591-A
Country	US
Kind code	B2
Filing date	Jun 26, 2013
Priority date	Jun 27, 2012
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

A method for driving a hybrid vehicle with a propulsion system including a combustion engine, an electric machine with a rotor and a stator and a planetary gear with three components including a sun gear, a ring gear and a planet wheel carrier, where an output shaft of the combustion engine is connected to a first component, an input shaft of a gearbox is connected to a second component and the rotor of the electric machine is connected to a third component. The vehicle is driven forward by the electric machine. The reverse gear engaged in the gearbox drives the third component of the planetary gear to rotate with a negative rotational speed while a brake brakes the first component. Thereafter, move the component brake to an open position, so that the output shaft of the combustion engine rotates with a positive rotational speed so that the combustion engine may be started.

First claim

The invention claimed is:

1. A method for driving a vehicle and starting a combustion engine in a propulsion system of the vehicle, wherein the propulsion system comprises:
a combustion engine including an output shaft,
an electric machine including a stator and a rotor,
a gearbox including an input shaft,
a planetary gear comprising three components including a sun gear, a ring gear and a planet wheel carrier,
the output shaft of the combustion engine is directly connected and secured to a first of the three components of the planetary gear such that rotation of the output shaft of the combustion engine causes rotation of the first component, the input shaft of the gearbox connected to a third of the three components of the planetary gear such that rotation of the input shaft of the gearbox causes rotation of the third component and the rotor of the electric machine is connected to a second one of the three components of the planetary gear, such that rotation of the rotor causes rotation of the second component,
locking means movable between a locking position in which two of the three components of the planetary gear are interlocked for causing the three components to rotate as a unit with a same rotational speed and a releasing position in which the three components are allowed to rotate with different respective rotational speeds, and
a component brake being so located and being movable between a braking position in which the rotation of the first component of the planetary gear is braked by the component brake, and an open position in which rotation of the first component of the planetary gear is not affected by the component brake;
the method comprising steps of:
a) driving the vehicle forward using the electric machine by engaging a reverse gear in the gearbox while the electric machine drives the third component of the planetary gear to rotate with a negative rotational speed, with the locking means in the releasing position and with the component brake in the braking position, and
b) moving the component brake to the open position, such that the output shaft of the combustion engine, via said the first component of the planetary gear, is rotated with a positive rotational speed, such that the combustion engine is in condition to be started.

2. The method according to claim 1 , further comprising the step of:
checking that a present torque of the electric machine is sufficient to provide a resulting torque on the output shaft of the combustion engine sufficient to start the combustion engine.

3. The method according to claim 2 , further comprising braking drive wheels of the vehicle while controlling the torque of the electric machine toward a value which provides sufficient resulting torque acting on the output shaft of the combustion engine to start the combustion engine, when the present torque of the electric machine is insufficient.

4. The method according to claim 1 , further comprising the steps of:
(c) controlling the electric machine and/or the combustion engine so that a state of a zero torque is reached in the gearbox,
(d) disengaging the reverse gear engaged in the gearbox,
(e) controlling the electric machine and/or the combustion engine such that a rotational speed of the ring gear together with a rotational speed of the output shaft of the combustion engine gives the input shaft of the gearbox a rotational speed which for a current velocity of the vehicle, is synchronized with a shaft rotational speed corresponding to a desired forward gear in the gearbox, and
(f) engaging the desired forward gear in the gearbox.

5. The method according to claim 4 , further comprising the steps of:
(g) checking demanded driving torque,
(h) controlling the torque of the electric machine towards a level that provides the demanded driving torque,
(i) simultaneously controlling the rotational speed of the combustion engine towards a value that provides the three components of the planetary gear with the same rotational speed, and
(j) moving the locking means to the locking position when said three components of the planetary gear rotate with the same rotational speed.

6. The method according to claim 1 , wherein the first component of the planetary gear is the sun gear, the second component of the planetary gear is the planet wheel carrier and the third component of the planetary gear is the ring gear.

7. The method according to claim 1 , wherein the propulsion system comprises a range gear.

8. The method according to claim 7 , wherein said reverse gear is provided in combination with a high range gear.

9. A computer program product including a non-volatile and non-transitory data storing medium and a computer program comprising computer program code stored on the medium and readable by a computer, the code enabling a computer to implement a method according to claim 1 when the computer program code is executed in the computer.

10. An electronic control unit comprising an execution means, a memory connected to the execution means and a non-volatile and non-transitory data storing medium connected to the execution means, the computer program code of the computer program product according to claim 9 stored on the data storing medium.

11. A vehicle comprising an electronic control unit according to claim 10 .

Assignees

• Scania Cv Ab

Inventors

• Pettersson Niklas
• Bergquist Mikael
• Lindström Johan
• Kjell Anders
• Björkman Mathias

Classifications

• B60W10/06 Primary

  including control of combustion engines · CPC title

• F02N15/046

  of the planetary type · CPC title

• B60W10/08

  including control of electric propulsion units, e.g. motors or generators · CPC title

• F02N5/04

  of inertia type · CPC title

• B60W10/115

  with planetary gears · CPC title