WO2015092320A1

WO2015092320A1 - Electromechanical system for recovering kinetic energy

Info

Publication number: WO2015092320A1
Application number: PCT/FR2014/053455
Authority: WO
Inventors: Pierre-Julian ANGELOT; Sylvain DECOSTER
Original assignee: Valeo Systemes De Controle Moteur
Priority date: 2013-12-19
Filing date: 2014-12-19
Publication date: 2015-06-25
Also published as: EP3083301A1; FR3015376A1; FR3015376B1

Abstract

The invention relates to an electromechanical system (10) for recovering kinetic energy for a vehicle, comprising: a first mechanical coupling to the wheels (30) of the vehicle; a second mechanical coupling to a flywheel (11); a third mechanical coupling to a reversible electric motor/generator machine (12); and at least one planetary gear train (20), of which the sun gears, the ring gear and the planet carrier are connected to the aforementioned couplings via, for at least one of same, a coupling system (40) having at least two ratios selected according to the power flows between the wheels of the vehicle, the flywheel and the electric machine.

Description

ELECTROMECHANICAL RECOVERY SYSTEM

KINETIC ENERGY

The present invention relates to electromechanical systems for recovering kinetic energy for vehicles, especially automobiles.

FR 2 967 619 discloses a hybrid vehicle comprising a kinetic energy recovery system with two epicyclic gear trains of different reasons, driven in parallel respectively by the engine and the electric motor of the vehicle. A system selectively couples one of these trains to an electric generator.

WO 2010/059041 A1 discloses a kinetic energy recovery system comprising a flywheel, an epicyclic gear train and a reversible motor / generator electric machine.

US 4,423,794 describes a similar system.

There is a need to improve the electromechanical kinetic energy recovery systems of the type comprising a flywheel, a reversible motor / generator electrical machine, in particular with the aim of optimizing the power flows, reducing the dimensioning of the components. increase the efficiency and / or reduce the overall cost.

The invention aims to meet all or part of these needs and it achieves this through an electromechanical system for recovering kinetic energy for vehicles, comprising:

a first mechanical connection to the wheels of the vehicle, a second mechanical link to a flywheel, a third mechanical connection to a reversible electric motor / generator machine,

at least one epicyclic gear train whose planet gear, ring gear and satellite carrier are connected to said links via, for at least one of them, a coupling system having at least two selected ratios depending on the power flows between the wheels of the vehicle, the flywheel and the electric machine.

The invention can reduce the size of the electric machine and / or, if desired, recover the kinetic energy of the steering wheel to drive the vehicle in reverse.

The flywheel can be connected directly to the epicyclic gear train.

The coupling means is disposed between the flywheel and the epicyclic gear train. A clutch can be arranged between the wheels, alternatively between the wheels and the electric machine.

The reversible electric machine can be two or four quadrants.

Preferably, the values of the ratios follow an arithmetic progression, alternatively a geometric progression, or alternatively an arithmetic-geometric progression.

Monitoring an arithmetic progression makes it possible to minimize the electrical power required, and monitoring a geometric progression makes it possible to minimize the variation of useful electrical energy and consequently that of the electrical energy storage element supplying electricity. the electric machine when it operates as a motor.

Preferably, the ratios are discrete, for example being 2, 3 or 4. As a variant, the ratios vary continuously. The coupling system can be connected between the epicyclic gear and the output to the wheels. In a variant, the coupling system is connected between the steering wheel and the epicyclic gear train.

The system can be made in such a way that the reports reverse the rotational speed between the input and the output of the coupling system.

The invention further relates to a vehicle equipped with a coupling system according to the invention.

The invention also relates to a vehicle equipped with a system according to the invention, as defined above.

The subject of the invention is also a method of supplying energy to the wheels of a vehicle by means of a system according to the invention, in which, successively:

a) the kinetic energy of the steering wheel is discharged to the wheels and the electric machine which operates as a generator,

b) the kinetic energy of the steering wheel is discharged to the wheels, and the electric machine operates as a motor to provide extra energy,

c) a transmission ratio is changed by acting on the coupling system,

d) the kinetic energy of the steering wheel is discharged to the wheels and the electric machine that operates as a generator, and

e) the kinetic energy of the steering wheel is discharged to the wheels, and the electric machine operates as a motor to provide extra energy.

The invention will be better understood on reading the detailed description which follows, examples of non-limiting implementation thereof, and on examining the appended drawing, in which: FIG. 1 schematically represents an exemplary system according to the invention,

FIG. 2 is a view similar to FIG. 1 of an alternative embodiment, FIGS. 3A to 3D show the power flows for different operating conditions of the system of FIG. 1,

FIGS. 4A to 4D represent the electrification rates in the configurations of FIGS. 3A to 3D respectively,

FIG. 5 is a view similar to FIG. 1 of an alternative embodiment; FIGS. 6A and 6B illustrate the power flows for the system of FIG. 5 for forward and reverse respectively, and

Figures 7 to 9 are views similar to Figure 1, other embodiments.

In the figures, the kinematic representation is only schematic and the connections can be made with more gears or otherwise, for example with chains or belts. Therefore, all the examples illustrated are valid for connections made in all the usual ways, with gear trains, pulleys and belts, chains ...

FIG. 1 shows an electromechanical system 10 for recovering kinetic energy according to the invention, comprising a flywheel 11, a reversible electric motor / generator 12, and at least one epicyclic gear train 20 having three inputs / outputs 21, 22 and 23.

The link is considered as an entry when the speed is imposed on the train and as an exit when the speed is imposed by the other entries. In the following, we define by k _cvt the opening ratio given by the ratio Wfly / w ₀ ut, where Wfiy is the speed of rotation of the flywheel and w _or t the speed of rotation of the output of the train, towards the wheels.

The electric power rate <5? _e \ _ec is given by σρ _ε ι _εε = -Pem Pout = 1 - (1 / (1 "λ) * k _cvt ) and CEelec = A _E elec A _E fly early = ½ * (w _{fly max} - W * fl _ym i ") ^A 2 / (w ² fl _ymax - W ² fl _ym i"), WHERE

Wfiy _max is the maximum speed of rotation of the flywheel, Wfl _ym i _n its minimum speed of rotation, at the end of the kinetic energy discharge, w * _{fly m} i _n the speed of synchronization between each report, P _em the power of the electric machine, P _or t the power output to the wheels, E _e i _ec the accumulated electrical energy, and E _fly the kinetic energy of rotation of the steering wheel.

One 23 of the inputs / outputs is connected to the wheels 30 of the vehicle, more at least directly, for example by means of a drive train consisting of a bridge equipped with a differential, not shown.

The input / output 22 is connected to the reversible machine 12.

The input / output 21 is connected to the flywheel 1 1 via a coupling system 40 offering at least two ratios, given in the example in question by two sets of gears, namely those referenced 41a, 42a on the one hand and those referenced 41b, 42b on the other hand.

The gears 41a and 41b rotate together and are driven by the inlet / outlet 21 of the epicyclic gear train 20.

The flywheel 1 1 is selectively driven by the pinion 42a or the pinion 42b according to the position of an element 43 which can be coupled, depending on its position, either with the pinion 42a or with the pinion 42b. The gear ratios offered by the coupling system are selected in such a way as to adapt the driveline to the characteristics of the epicyclic gear train. The opening of the latter is sized according to various criteria such as acoustics, static mechanical resistance, dynamic or endurance or performance. The coupling system aims to provide a balance between minimizing the electrical power required via the size of the electrical machine and minimizing the variation of useful electrical energy by reducing the size of the electrical storage element such as a battery, and the values of the discrete ratios are chosen accordingly.

To minimize the electrical power required, the values of the ratios follow a geometrical law, whereas to minimize the variation of useful electrical energy, the values will follow an arithmetic law.

In the example of Figure 1, the coupling system is placed on the side of the flywheel and in Figure 2 on the side of the transmission chain.

The presence of discrete ratios inserted in the kinematic chain makes it possible to change the input / output speeds of the epicyclic gear train, thus the power flows and the transferred energies.

When moving from one report to another, a synchronization phase may be necessary.

The power flows during the operation of the system will be described with reference to FIGS. 3A to 3D.

In Figure 3A, the kinetic energy of the flywheel 11 is discharged to the electric machine and to the drive chain. The electric machine 12 operates as a generator. If we refer to the corresponding figure 4A, we see that the power of the electric machine can change between -P _e i _ec max and 0. In FIG. 3B, the kinetic energy of the steering wheel continues to be discharged, but a booster of energy is provided by the electric machine 12 which operates as a motor. In the corresponding figure 4B, we see that the power of the electric machine can change between 0 and + P _e iec max.

A change of ratio occurs between the configurations of FIGS. 3B and

3C. This change of ratio allows the flywheel 11, which continues to discharge, to drive again the electric machine 12 which can operate as a generator. The electrification rate may again change between -P _e i _ec max and 0, as illustrated in FIG. 4C. Once the electrification rate becomes positive, as shown in FIG. 4D, the flywheel can be discharged to the wheels while an energy boost is provided by the electric machine 12 which operates as a generator, as illustrated in FIG. 3D figure.

As the number of ratio values increases, the electric power and electrical energy rates decrease.

The coupling system 40 may consist of a continuously variable gearbox (also called CVT). In this case, the coupling system 40 is for example disposed between the epicyclic gear train 20 and the flywheel 11 as illustrated in FIG. 8 or between the epicyclic gear train 20 and the wheels 30, as illustrated in FIG. it is preferred in the invention, for cost reasons, to use a coupling system 20 with a number of discrete ratios, preferably equal to 2, 3 or 4.

When the vehicle is moving forward, the input / output speeds are a constant sign, as the wheels always turn in the same direction, as is the flywheel.

When it is desired to drive in reverse, the direction of rotation of the wheels must reverse. The ratio k _cvt changes sign, and the epicyclic train goes into said mode electric recirculation. The electric power becomes greater than the output power, and the electric machine 12 can saturate, which decreases the performance of the system 10. In addition, the input speed reverses, the speed of the electric machine 12 increases significantly. significant until it reaches its maximum speed, beyond which it becomes unusable.

Increasing the opening of the epicyclic gear train 20 may make it possible to avoid these limitations, but has the effect of increasing the power and electrical energy necessary for normal operation in the forward direction.

Thus, preferably, the coupling system 40 is designed to reverse the rotation speed with respect to the epicyclic gear train, as shown in FIG. 5.

It can be seen in this FIG. 5 as well as in FIGS. 6A and 6B that the pinions 41a, 41b, 42a and 42b can be arranged to reverse the direction of rotation of the flywheel 11 for the epicyclic gear train 20, depending on whether the coupling element is coupled to pinion 42a or pinion 42b, which rotate in opposite directions. Figure 6A is forward and Figure 6B is reverse.

FIG. 7 illustrates the possibility of arranging the coupling system 40 so as to reverse the speed of the connection of the sun gear to the wheels 30.

The invention is not limited to the illustrated examples. In particular, it is possible to multiply the coupling systems so for example to be able to change both the ratios to the flywheel and to the wheels.

The phrase "having one" is synonymous with "having at least one".

Claims

An electromechanical system (10) for kinetic energy recovery for a vehicle, comprising:

a first mechanical connection to the wheels (30) of the vehicle, a second mechanical link to an inertia flywheel (11),

a third mechanical link to a reversible motor / generator electric machine (12),

at least one epicyclic gear train (20) whose planet gear, ring gear and satellite carrier are connected to said links via, for at least one of them, a coupling system (40) having at least two selected ratios depending on the flows power between the vehicle wheels, the flywheel and the electric machine

2. System according to claim 1, the reversible electric machine being two quadrants.

3. System according to claim 1, the reversible electric machine being four quadrants.

4. System according to any one of claims 1 to 3, the values of the reports following an arithmetic progression.

5. System according to any one of claims 1 to 3, the values of the reports in a geometric progression.

6. System according to any one of claims 1 to 3, the values of the reports following an arithmetic-geometric progression.

7. System according to any one of the preceding claims, the reports being discrete.

8. System according to any one of claims 1 to 6, the ratios varying continuously.

9. System according to any one of the preceding claims, the coupling system (40) being connected between the epicyclic train (20) and the output of the train to the wheels (30).

10. System according to any one of claims 1 to 8, the coupling system (40) being connected between the wheel (11) and the epicyclic gear (20).

11. System according to any one of the preceding claims, one of the reports reversing the speed of rotation between the input and the output of the coupling system.

12. Vehicle equipped with a system as defined in any one of the preceding claims.

13. A method of supplying energy to the wheels of a vehicle using a system as defined in any one of claims 1 to 11, wherein, successively:

c) a transmission ratio is changed by acting on the coupling system,