JP2014051247A - Vehicle driving mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle driving mechanism including an engine and a double-rotor type motor as power sources and capable of reducing loss generated due to power circulation while maintaining charging amount of a battery in a high speed cruising state.SOLUTION: A vehicle driving mechanism 100 includes an engine 10, a double-rotor type motor 20, a battery 30, and a control unit 40. In a high speed cruising state of a vehicle, the control unit 40 reduces output torque Tof the engine 10 when charging amount (SOC) of the battery 30 is more than a prescribed threshold Th and increases the output torque Tof the engine 10 when the charging amount of the battery 30 is less than the prescribed threshold Th.

Description

  The present invention relates to a vehicle drive mechanism, and more particularly to a vehicle drive mechanism of a hybrid vehicle including an engine and a motor as power sources.

  The spread of hybrid vehicles equipped with engines and motors as power sources has begun. FIG. 8 of Patent Document 1 discloses a vehicle drive mechanism of a hybrid vehicle including an engine and a double rotor type motor. The double rotor type motor disclosed here includes a first rotor coupled to an engine drive shaft, a second rotor disposed radially outside the first rotor and coupled to an axle, and a second rotor. And a stator that is disposed radially outside the rotor and is fixed to the housing. The first rotor is provided with a first coil, and the stator is provided with a second coil. A first magnet is provided on the inner peripheral side of the second rotor so as to face the first coil of the first rotor, and on the outer peripheral side of the second rotor, the second coil of the stator faces. A second magnet is provided as described above. The first and second coils are connected to the battery via a power conversion unit capable of DC-AC mutual conversion, and exchange power with the battery.

  In a hybrid vehicle equipped with the vehicle drive mechanism described above, in a traveling state in which the rotational speed of the axle exceeds the rotational speed of the engine and the output torque of the engine is greater than the required torque of the axle (hereinafter referred to as “high-speed cruise state”) The vehicle travels as the first rotor is rotated by the power of the engine and the second rotor is rotated by electric power from the battery. Further, when the second rotor rotates, an induced voltage is generated in the second coil to generate power. The AC power generated at this time is converted into DC power by the power conversion unit, part of which is converted again into AC power and supplied to the first coil, and the rest is charged into the battery.

JP-A-2005-47396

  In the above high-speed cruise state, a power circulation occurs in which a part of the electric power generated by the second coil is supplied to the first coil of the first rotor due to the rotation of the second rotor. Since a part of it is lost when passing through the conversion unit, loss occurs along with the power circulation from the second coil to the first coil. As will be described later, if the engine output torque is reduced, the power circulating from the second coil to the first coil can be reduced to reduce the loss accompanying the power circulation, but at the same time the battery is charged. Electricity will also decrease. Therefore, it is preferable to avoid reducing the output torque of the engine in a state where the charge amount of the battery is small.

  The present invention has been made to solve such a problem, and is a vehicle drive mechanism including an engine and a double rotor type motor as a power source, while maintaining the charge amount of a battery in a high-speed cruise state. It aims at providing the vehicle drive mechanism which can reduce the loss which generate | occur | produces with power circulation.

  In order to solve the above problems, a vehicle drive mechanism according to the present invention includes an internal combustion engine (engine) that generates power by burning fuel, and a first mechanically connected to the internal combustion engine via a drive shaft. A rotor, a second rotor disposed on the outer side in the radial direction of the first rotor and mechanically coupled to the axle, and a stator disposed on the outer side in the radial direction of the second rotor, One of the first rotor and the second rotor has a first coil, and the other has a first magnet or a first magnetic salient pole, and one of the second rotor and the stator has a second coil. And the other having a second magnet or a second magnetic salient pole part, a rotating electrical machine (double rotor type motor), power storage means (battery) electrically connected to the first and second coils of the rotating electrical machine, The rotational speed of the second rotor exceeds the rotational speed of the first rotor, and the internal combustion machine When the output torque is greater than the required torque of the axle, characterized in that it comprises a control means for controlling the output torque of the internal combustion engine based on the charge amount of the power storage means.

  Preferably, the control means reduces the output torque of the internal combustion engine when the charge amount of the power storage means exceeds a predetermined threshold value, and when the charge amount of the power storage means falls below a predetermined threshold value. Increase the output torque of the internal combustion engine.

More preferably, the control means has the output torque T _{E of} the internal combustion engine, the rotational speed of the internal combustion engine ω _E , the required torque of the axle T _W , the rotational speed of the axle ω _W , and the power supplied from the internal combustion engine. If the conversion efficiency of η and the charging power required for the power storage means are P _BAT ′, and the charge amount of the power storage means exceeds a predetermined threshold, the output torque of the internal combustion engine is expressed as T _E = (T _W · When it is decreased to a value calculated according to ω _W ) / (η · ω _E ) and the charge amount of the power storage means is below a predetermined threshold, the output torque of the internal combustion engine is expressed as T _E = (P _BAT ' Increase to a value calculated according to + T _W · ω _W ) / ω _E.

  According to the vehicle drive mechanism according to the present invention, it is possible to reduce a loss caused by power circulation while maintaining a charge amount of a battery in a high-speed cruise state.

It is a figure which shows the structure of the vehicle drive mechanism which concerns on embodiment of this invention. It is a flowchart which shows the control performed by the control unit in the vehicle drive mechanism which concerns on embodiment of this invention. It is the figure which defined an example of the relationship between the charge amount of the battery in the vehicle drive mechanism which concerns on embodiment of this invention, and the charging power required in that case. It is the figure which defined another example of the relationship between the charge amount of the battery in the vehicle drive mechanism which concerns on embodiment of this invention, and the charging power required in that case. It is a figure which shows the various structures of the double rotor type motor in the 1st modification of the vehicle drive mechanism which concerns on embodiment of this invention. It is a figure which shows the various structures of the double rotor type | mold motor in the 2nd modification of the vehicle drive mechanism which concerns on embodiment of this invention. It is a figure which shows the various structures of the double rotor type | mold motor in the 3rd modification of the vehicle drive mechanism which concerns on embodiment of this invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
Embodiment.
FIG. 1 shows the configuration of a vehicle drive mechanism 100 for a hybrid vehicle according to an embodiment of the present invention.
The vehicle drive mechanism 100 includes an engine 10 that generates gasoline by burning gasoline fuel therein, and a double rotor motor 20 that operates by three-phase AC power as power sources. The double rotor type motor 20 is mechanically connected to the drive shaft 11 of the engine 10, and is arranged on the radially outer side of the first rotor 21 and a first rotor 21 that rotates integrally with the drive shaft 11 at the same speed. A second rotor 22 that is mechanically coupled to the axle 14 via the arm 12 and the differential 13 and rotates at the same speed as the axle 14; and a motor casing disposed radially outside the second rotor 22 And a stator 23 fixed to 24. The first rotor 21 has a cylindrical shape, the second rotor 22 and the stator 23 have an annular shape, and FIG. 1 schematically shows a cross section thereof.

  The first rotor 21 is provided with a first coil 25, and the stator 23 is provided with a second coil 26. A first magnet 27 is provided on the inner peripheral side of the second rotor 22 so as to face the first coil 25 of the first rotor 21, and the stator 23 is provided on the outer peripheral side of the second rotor 22. A second magnet 28 is provided so as to face the second coil 26. The first magnet 27 and the second magnet 28 may be provided integrally.

  The vehicle drive mechanism 100 includes a battery 30 and power conversion units 31 and 32. The battery 30 is capable of charging / discharging direct current power, and exchanges power with the double rotor motor 20 via the power conversion units 31 and 32. The power conversion units 31 and 32 convert the DC power output from the battery 30 into three-phase AC power and output it to the double rotor type motor 20, and the three phase AC power is regenerated from the double rotor type motor 20. If it is, it is converted to DC power and output to the battery 30.

  A slip ring 33 that rotates integrally with the first rotor 21 and a brush 34 that contacts the slip ring 33 are provided in the middle of the drive shaft 11. The power conversion unit 31 includes a brush 34, a slip ring 33. , And a conductive wire (not shown) wired along the drive shaft 11, and is electrically connected to the first coil 25 of the first rotor 21. On the other hand, the power conversion unit 32 is electrically connected to the second coil 26 of the stator 23.

The control unit 40 controls the operation of the engine 10 and also controls the power conversion units 31 and 32 to control the power transfer between the battery 30 and the double rotor type motor 20. Further, the control unit 40, based on information from various sensors (not shown) provided in the vehicle, outputs torque T _E and rotational speed ω _{E of} the engine 10, required torque T _W and rotational speed ω _{W of} the axle 14, In addition, the charge amount (SOC) of the battery 30 can be acquired.

Next, the operation in the high-speed cruise state in the vehicle drive mechanism 100 of the hybrid vehicle according to this embodiment will be described. Incidentally, as described above, in the present specification, "high-speed cruising state", the rotational speed omega _W axle 14 exceeds the rotation speed omega _E of the engine 10, and axle output torque T _E of the engine 10 It refers to a larger state than the required torque _{T W} of 14.

  In this high-speed cruise state, when the first rotor 21 is rotated by the power supplied from the engine 10, an induced voltage is generated in the first coil 25 by the action of the magnetic field generated by the first magnet 27 of the second rotor 22. An induced current flows. Due to the interaction between the induced current and the magnetic field, torque is generated between the first rotor 21 and the second rotor 22, the second rotor 22 rotates, and the axle 14 connected to the second rotor 22 is driven. The vehicle travels.

  When the second rotor 22 rotates, the magnetic field generated by the second magnet 28 acts on the second coil 26 of the stator 23 to generate an induced voltage in the second coil 26 to generate power. The AC power generated at this time is converted into DC power by the power conversion unit 32, a part of which is converted back to AC power by the power conversion unit 31 and supplied to the first coil 25 of the first rotor 21, The remaining battery 30 is charged.

The power balance of the vehicle drive mechanism 100 in such a traveling state is that the power supplied from the engine 10 is P _E , the power supplied to the first coil 25 is P _I , the power required by the axle 14 is P _W , If the electric power generated by the two coils 26 is _PO , it is expressed as follows.

ηP _E + P _I = P _W + P _O (1)

However, in the above equation, eta is the efficiency of power conversion P _E supplied from the engine 10, it takes a value in the range of 0-1.

Also, assuming that the power charged in the battery 30 is P _BAT , the charge power P _BAT is the difference between the power P _O generated by the second coil 26 and the power P _I supplied to the first coil 25 as follows: It is expressed as

_{P BAT = P O -P I (} 2)

  Here, when Expression (1) is rewritten using Expression (2), it becomes as follows.

ηP _E = P _W + P _BAT (3)

Further, the power P _E supplied from the engine 10 and the power P _W required by the axle 14 are expressed as follows, respectively.

P _E = T _E · ω _E (4)
P _W = T _W · ω _W (5)

However, in the above equation, _{T E} the output torque of the engine 10, omega _E is the rotational speed, _{T W} of the engine 10 is required torque, omega _W axle 14 is the rotational speed of the axle 14.

The power P _I to be supplied to the power P _O, and the first coil 25 is generated by the second coil 26 are respectively expressed as follows.

P _O = (T _E −T _W ) · ω _W (6)
_{P I = T E · (ω} W -ω E) (7)

Referring again to FIG. 1 in light of the above matters, the in the vehicle drive mechanism 100 in a high-speed cruise condition, part of the power P _O is generated by the second coil 26 by the rotation of the second rotor 22 as power P _I Power circulation supplied to the first coil 25 of one rotor 21 occurs. A part of the electric power circulated at this time is lost when passing through the power conversion units 32 and 31, and thus a loss occurs with the power circulation from the second coil 26 to the first coil 25.

As can be seen from equation (7), if reducing the output torque T _E of the engine 10, the power P _I supplied to the first coil 25 can be reduced, the power conversion unit 32 from the second coil 26, The electric power circulated to the first coil 25 via 31 can be reduced. As a result, it is possible to reduce the loss that occurs with the power circulation. However, if the expressions (6) and (7) are substituted into the expression (2), the following relationship is obtained.

_{P BAT = T E · (ω} W -ω E) (8)

That is, when the output torque _{T E} of the engine 10 decreases, also decreases power _{P BAT} of the battery is recharged 30. Therefore, in the state of charge is small in the battery 30, to reduce the output torque T _E of the engine 10 in order to reduce the losses associated with power circulation is preferably avoided.

Based on the above knowledge, when the current charge amount (SOC) of the battery 30 exceeds the predetermined threshold Th, the control unit 40 outputs the output of the engine 10 in order to reduce the loss due to power circulation. reduce the torque _{T E.} On the other hand, when the amount of charge is below a predetermined threshold value Th, in order to prioritize charging of the battery 30 than the reduction in losses associated with the power circulation, to increase the output torque T _E of the engine 10. More specifically, the control unit 40 executes the control shown in the flowchart of FIG. 2 at predetermined time intervals.

In the control flow of FIG. 2, the control unit 40 first determines in step S1 whether or not the rotational speed ω _W of the axle 14 exceeds the rotational speed ω _E of the engine 10, and in step S2, the output of the engine 10 is determined. the torque T _E is determined whether greater than the required torque T _W of the axle 14. These determination processes are for determining whether or not the vehicle is in a high-speed cruise state. If both steps S1 and S2 are YES, it is determined that the vehicle is in a high-speed cruise state. The process after S3 is performed. On the other hand, if either of steps S1 and S2 is NO, it is determined that the vehicle is not in a high-speed cruise state, and the control flow is exited.

When it is determined YES in both steps S1 and S2, the control unit 40 determines whether or not the current charge amount of the battery 30 exceeds a predetermined threshold Th in step S3. If the charge amount of the battery 30 exceeds a predetermined threshold Th, the output of the engine 10 is reduced in step S4 in order to reduce the loss associated with power circulation from the second coil 26 to the first coil 25. the torque T _E, is reduced to a value which is calculated according to the following equation (9).

T _E = (T _W · ω _W ) / (η · ω _E ) (9)

The above equation (9) is obtained by substituting the equations (4) and (5) with the charging power P _BAT = 0 for the battery 30 in the equation (3).

On the other hand, when the charge amount of the battery 30 is below a predetermined threshold value Th, the control unit 40, in step S5, to increase the output torque T _E of the engine 10 to increase the charge amount of the battery 30. Specifically, as shown in FIG. 3, the relationship between the charge amount of the battery 30 and the charge power required at that time is determined in advance, and the required charge power P _{BAT is} determined based on the current charge amount of the battery 30. 'seek, the required charging power P _BAT' the output torque T _E corresponding to calculated according to the following equation (10), is increased to a value which is calculated the output torque T _E of the engine 10.

T _E = (P _BAT '+ T _W · ω _W ) / ω _E (10)

The above equation (10) is obtained by substituting the equations (6) and (7) by substituting the charging power P _BAT = P _BAT 'into the battery 30 in the equation (2). Further, the method of determining the relationship between the charge amount of the battery 30 and the necessary charging power P _BAT ′ is not limited to the relationship illustrated in FIG. 3, and may be determined, for example, as illustrated in FIG. 4.

As described above, in the vehicle drive mechanism 100 of the hybrid vehicle according to this embodiment, the output torque T of the engine 10 when the charge amount of the battery 30 exceeds the predetermined threshold Th in the high-speed cruise state. _E was reduced to the value calculated according to equation (9), when the charge amount of the battery 30 is below a predetermined threshold value Th, the output torque T _E of the engine 10 until it is calculated according to equation (10) increase. Thereby, in the high-speed cruise state, it is possible to reduce the loss caused by the power circulation while maintaining the charge amount of the battery 30.

Other embodiments.
(First modification)
In the double rotor type motor 20 in the above embodiment, as shown in FIG. 1, the first coil 25, the first magnet 27, the second magnet 28, and the second coil 26 are provided in this order from the radially inner side. In the first rotor 21 and the second rotor 22, one has the first coil 25 and the other has the first magnet 27, and in the second rotor 22 and the stator 23, one is the second. Any structure having the coil 26 and the other having the second magnet 28 may be used. Therefore, for example, a structure as shown in FIGS. In FIG. 5A, the first magnet 27a, the first coil 25a, the second magnet 28a, and the second coil 26a are provided in this order from the radially inner side. In FIG. 5B, the first magnet 27b, the first coil 25b, the second coil 26b, and the second magnet 28b are provided in this order from the radially inner side. In FIG. 5C, the first coil 25c, the first magnet 27c, the second coil 26c, and the second magnet 28c are provided in this order from the radially inner side.

(Second modification)
Further, in the double rotor type motor 20 of the above-described embodiment, a known synchronous reluctance motor (SynRM) is configured by forming the second rotor body from a magnetic steel sheet and forming a magnetic salient pole portion. May be.

  In FIG. 6A, the structure in which the second magnet 228a is provided on the radially outer side of the second rotor 222a and the second coil 226a is provided on the stator 223a is the same as that of the above-described embodiment. Four flux barrier portions 229a having a multilayer slit structure are formed on the radially inner side of 222a, and four first magnetic salient pole portions 231a are formed between the respective flux barrier portions 229a and 229a. The first coil 225a of the first rotor 221a is a distributed winding type, and the first rotor 221a and the second rotor 222a constitute a SynRM.

  In FIG. 6B, the structure in which the first coil 225b is provided in the first rotor 221b and the first magnet 227a is provided radially inward of the second rotor 222b is the same as in the above embodiment. Four second magnetic salient pole portions 232b are formed on the outer side in the radial direction of the two rotor 222b, and the second coil 226b of the stator 223b is a distributed winding type, and a SynRM is configured by the second rotor 222b and the stator 223b. Yes.

  In FIG. 6C, four first magnetic salient pole portions 231c are formed on the radially inner side of the second rotor 222c, and four second magnetic salient pole portions 232c are formed on the radially outer side. The first and second coils 225c and 226c are both distributed winding type, and the inner rotor 221c and the second rotor 222c constitute an inner SynRM, and the second rotor 222c and the stator 223c constitute an outer SynRM. .

(Third Modification)
Further, in the double rotor type motor 20 of the above-described embodiment, the main body of the second rotor is made of an electromagnetic steel plate to form a magnetic salient pole part, and a coil facing the magnetic salient pole part A well-known switched reluctance motor (SRM) may be formed by forming a salient pole structure in a concentrated winding type.

  In FIG. 7A, six first magnetic salient pole portions 332a are formed on the radially inner side of the second rotor 322a, and the first coil 325a of the first rotor 321a is a concentrated winding type and has a salient pole structure. Is formed, and the first rotor 321a and the second rotor 322a constitute an SRM.

  In FIG. 7B, six second magnetic salient pole portions 333b are formed on the radially outer side of the second rotor 322b, and the second coil 326b of the stator 323b is a concentrated winding type to form a salient pole structure. The SRM is configured by the second rotor 322b and the stator 323b.

  In FIG. 7C, first and second magnetic salient pole portions 332c and 333c are formed on the inner side and the outer side of the second rotor 322c in the radial direction, respectively, and the first and second coils 325c and 326c are concentrated winding type. Thus, a salient pole structure is formed, and an inner SRM is constituted by the first rotor 321c and the second rotor 322c, and an outer SRM is constituted by the second rotor 322c and the stator 323c.

DESCRIPTION OF SYMBOLS 100 Vehicle drive mechanism, 10 engine (internal combustion engine), 11 drive shaft, 14 axle, 20 double rotor type motor (rotary electric machine), 21 1st rotor (1st rotor), 22 2nd rotor (2nd rotor) ), 23 Stator (stator), 25 1st coil, 26 2nd coil, 27 1st magnet, 28 2nd magnet, 30 battery (power storage means), 40 control unit (control means), output torque of _TE engine rotational speed (output torque of the internal combustion engine), omega _E engine (rotational speed of the internal combustion engine), the required torque of T _W axle, the rotation speed of the omega _W axles, the conversion efficiency (internal combustion engine of the power supplied from η engine (Conversion efficiency of power to be supplied), P _BAT ′ charge power required for the battery (charge power required for the power storage means), Vt predetermined threshold.

Claims (3)

An internal combustion engine that generates power by burning fuel;
A first rotor mechanically coupled to the internal combustion engine via a drive shaft; a second rotor disposed radially outside the first rotor and mechanically coupled to an axle; and A stator disposed radially outward of the second rotor, wherein one of the first rotor and the second rotor has a first coil and the other is a first magnet or a first magnetic salient pole. A rotating electrical machine, wherein one of the second rotor and the stator has a second coil and the other has a second magnet or a second magnetic salient pole,
Power storage means electrically connected to the first and second coils of the rotating electrical machine;
When the rotational speed of the second rotor exceeds the rotational speed of the first rotor and the output torque of the internal combustion engine is larger than the required torque of the axle, the internal combustion engine is based on the charge amount of the power storage means. A vehicle drive mechanism comprising control means for controlling the output torque of the engine.   The control means reduces the output torque of the internal combustion engine when the charge amount of the power storage means exceeds a predetermined threshold, and when the charge amount of the power storage means falls below the predetermined threshold. The vehicle drive mechanism according to claim 1, wherein an output torque of the internal combustion engine is increased. The control means is supplied from the internal combustion engine with the output torque of the internal combustion engine being T _E , the rotational speed of the internal combustion engine being ω _E , the required torque of the axle being T _W , and the rotational speed of the axle being ω _W. Assuming that the power conversion efficiency is η and the charging power required for the power storage means is P _BAT ′,
When the amount of charge of the power storage means exceeds the predetermined threshold, the output torque of the internal combustion engine is
T _E = (T _W · ω _W ) / (η · ω _E )
To the value calculated according to
When the amount of charge of the power storage means is below the predetermined threshold, the output torque of the internal combustion engine is
T _E = (P _BAT '+ T _W · ω _W ) / ω _E
The vehicle drive mechanism according to claim 2, wherein the vehicle drive mechanism is increased to a value calculated according to

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