JPH09224302A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To utilize an electric condenser efficiently. SOLUTION: In a vehicle, an engine 11, a generator 16, and a drive output shaft 31 are connected to each gear element of a planetary gear unit 13 and the vehicle is driven by the output of an electric motor 25 connected to the drive output shaft 31 and engine output. The target voltage of the capacitor is increased at a low speed and is decreased at a high speed, namely is changed according to driving condition and capacitor characteristics. Also, the speed of the generator 16 is accurately controlled, thus setting the capacitor voltage to the above target voltage and fully utilizing the capacitor capacity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid vehicle equipped with an engine and an electric motor, and more particularly to a hybrid vehicle characterized by controlling the amount of electricity stored in a power storage device that supplies electric power to the electric motor. .

[0002]

2. Description of the Related Art Conventionally, a vehicle is equipped with an internal combustion engine such as a gasoline engine or a diesel engine as a drive source, and burns gasoline or light oil to obtain energy for traveling. These drive sources have the advantages of being able to obtain a high output and being capable of running over a long distance, but CO ₂ , NO, and NO emitted from the combustion of the fuel.
There is a problem that gases such as _x adversely affect the environment.

Therefore, with the recent depletion of fossil energy and increasing environmental problems, development of vehicles with low noise and low pollution has been desired, and among them, electric vehicles are the most noticeable ones. . This electric vehicle uses an electric motor as a drive source, drives the electric motor by electric power stored in a battery, and runs, and has the advantages of no exhaust gas and low noise.

However, since this electric vehicle is equipped with a heavy battery, the weight of the vehicle becomes heavy, the traveling efficiency is lowered, and sufficient output cannot be obtained only with the electric power stored in the battery. It has the drawback that it cannot perform sudden acceleration or long-distance driving. Furthermore, in order to reuse a battery that has been used up once, a long storage time is required, and the range of use must be limited.

Therefore, a hybrid vehicle equipped with an internal combustion engine and an electric motor has been proposed. Various hybrid vehicles are provided. For example, the rotation generated by driving an engine is transmitted to a generator to drive the generator, and the electric power obtained by the generator is sent to a battery to store electricity. In addition, a series (series) type hybrid vehicle configured to drive the electric motor by the electric power of the battery, or a parallel (parallel) type in which the driving force of the engine and the electric motor are respectively transmitted to the output shafts to drive the vehicle. ) There is a hybrid vehicle.

Since these hybrid vehicles have an electric motor as a drive source, regenerative electric power can be generated by the electric motor during deceleration and stored in the battery, and energy consumption efficiency can be improved.

[0007]

In the above hybrid vehicle, since the power consumption becomes large at the time of starting or acceleration from low speed running, it is necessary to increase the storage capacity. However, when decelerating during high-speed traveling, the kinetic energy for deceleration is regenerated and a large amount of electric power is supplied to the battery, so the battery requires a storage capacity for the amount of regeneration.

Therefore, in order to adapt the battery to the required conditions at low speed and high speed, it is necessary to make the storage capacity sufficiently large, but in order to increase the storage capacity, many batteries must be mounted. I have to. However, since a vehicle equipped with a battery has a limited mounting amount, it is necessary to satisfy the necessary conditions at low speed and high speed without increasing the mounting amount of the battery.

Conventionally, in order to solve such a problem,
A power storage control method for a secondary battery as disclosed in Japanese Patent Publication No. 6-12932 has been proposed. This method controls the target charge rate so that the charge amount of the secondary battery is always within a certain range. However, the amount of electric power stored in the battery and the electric power supplied by the regeneration of the electric motor greatly change depending on the running state at that time. For example, when a large amount of electric power is required, such as when the vehicle suddenly starts uphill (time t ₀ ) as shown in the time chart of FIG. 16, the remaining battery level is the lower limit. (Time t ₁ ) and the electric power tends to be insufficient, or the vehicle rapidly decelerates from high speed and overcharge occurs (time t ₂ ) beyond the remaining capacity. In other words, like the above conventional control method,
If the target charge rate is set to be constant regardless of the running state, there is still a possibility that overcharge or insufficient power may occur.

Further, the electric power supplied from the storage means is
It may change depending on the charge rate at the time of supply, and this change rate also differs depending on the means for storing electric power. In this way, when the output power differs depending on the charge rate, if the target charge rate is uniquely set as in the above-mentioned conventional example, even if the target charge amount is reached, the power is supplied to the electric motor. There is a possibility that there will be a shortage of power to operate.

According to the present invention, the target charge rate is changed according to the operating condition of the automobile and the output characteristic of the charge storage means, so that the electric energy can be used efficiently and the life of the charge storage means can be extended. To provide a vehicle.

[0012]

This and other objects are attained by the present invention described below.

(1) An engine, an electric motor for outputting a driving force to driving wheels, a storage means for supplying driving power to the electric motor, a vehicle speed detecting means for detecting a vehicle speed, and a vehicle speed detecting means for detecting the vehicle speed. A hybrid vehicle comprising: a changing unit that changes a target charge rate of the power storage unit; and a charge amount control unit that controls the electric power supplied to the power storage unit so as to reach the target charge rate.

(2) The hybrid vehicle according to the above (1), wherein the changing means reduces the target charge rate of the power storage means in response to an increase in vehicle speed.

(3) Further, a generator whose rotation speed is controllable, a first gear element on the output shaft of the engine, a second gear element on the rotor of the generator, and a third gear element on the output shaft of the engine. A differential gear device connected to a drive output shaft for transmitting a driving force to a drive wheel, wherein the storage amount control means controls a rotation speed of the generator according to the target storage ratio. The hybrid vehicle according to (1) or (2) above, which is a means.

(4) The hybrid vehicle according to the above (3), further comprising torque correction means for correcting the motor output torque of the electric motor according to the torque fluctuation caused by the rotation speed control by the generator control means.

(5) The power storage means has a capacitor, and in a region where the required output voltage of the capacitor with respect to the vehicle speed is higher than the output voltage at the target power storage rate, the target power storage rate is set high in accordance with the increase in the vehicle speed. (1) above
The hybrid vehicle according to any one of (4) to (4).

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION

<First Embodiment> Hereinafter, a first embodiment of a hybrid vehicle of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a conceptual diagram showing a drive device for a hybrid vehicle according to a first embodiment of the present invention. In the figure, the engine 11 and the engine output shaft 12 that outputs the rotation generated by driving the engine 11 are on the first axis.
A planetary gear unit 13 that is a differential gear device that changes the speed of rotation input through the engine output shaft 12, and a unit output shaft 14 that outputs the rotation of the planetary gear unit 13 after speed change, A first counter drive gear 15 fixed to the unit output shaft 14, a generator 16 that mainly acts as a generator in a normal traveling state, and a transmission shaft 17 that connects the generator 16 and the planetary gear unit 13 are arranged. Has been done. The unit output shaft 14 has a sleeve shape and is disposed so as to surround the engine output shaft 12. The first counter drive gear 15 is disposed closer to the engine 11 than the planetary gear unit 13.

The planetary gear unit 13 rotatably rotates a sun gear S which is a second gear element, a pinion P which meshes with the sun gear S, a ring gear R which is a third gear element which meshes with the pinion P, and a pinion P. And a carrier CR that is a first gear element that is supported by.

The sun gear S is connected to the generator 16 via the transmission shaft 17, and the ring gear R is connected to the unit output shaft 14
Is connected to the first counter drive gear 15 via the engine 1 and the carrier CR is connected to the engine 1 via the engine output shaft 12.
It is connected to 1.

Further, the generator 16 is fixed to the transmission shaft 17, and is rotatably disposed on the rotor 21, and the rotor 21.
And a coil 23 wound around the stator 22. The generator 16 is
Electric power is generated by the rotation transmitted via the transmission shaft 17. The coil 23 is connected to a capacitor (not shown) and supplies electric power to the capacitor to charge it.

In the generator 16, the other end of the transmission shaft 17 is
A brake B, which is an engaging means, is connected, and by bringing the brake B into an engaged state, the rotor 21 is fixed, and the rotation of the generator 16 and the rotation of the sun gear S are stopped. .

On the second axis parallel to the first axis, the electric motor 25, the motor output shaft 26 for outputting the rotation of the electric motor 25, and the second counter drive gear 27 fixed to the motor output shaft 26. And are arranged.

The electric motor 25 is fixed to the motor output shaft 26 and is rotatably arranged on the rotor 37, the stator 38 arranged around the rotor 37, and the stator 3.
And a coil 39 wound around 8. The electric motor 25 generates torque by the current supplied to the coil 39. For that purpose, the coil 39 is connected to a capacitor (not shown), and a current is supplied from the capacitor.

When the hybrid vehicle of the present invention is in a decelerating state, the electric motor 25 receives rotation from drive wheels (not shown) to generate regenerative power, and supplies the regenerative power to the capacitor for charging. Then, in order to rotate the drive wheels (not shown) in the same direction as the rotation of the engine 11, the first
A counter shaft 31 is arranged as a drive output shaft on a third axis parallel to the axis and the second axis. A counter driven gear 32 is fixed to the counter shaft 31.

Further, the counter driven gear 32 and the first
The counter drive gear 15 and the counter driven gear 32 are meshed with the second counter drive gear 27, and the rotation of the first counter drive gear 15 and the rotation of the second counter drive gear 27 are reversed and transmitted to the counter driven gear 32. It is supposed to be done.

Further, a diff pinion gear 33 having a smaller number of teeth than the counter driven gear 32 is fixed to the counter shaft 31. A differential ring gear 35 is provided on a fourth axis parallel to the first axis, the second axis, and the third axis, and the differential ring gear 35 and the differential pinion gear 33 are meshed. The differential ring gear 3
5, a differential device 36 is fixed, and the rotation transmitted to the differential ring gear 35 is made differential by the differential device 36 and transmitted to drive wheels.
In the above configuration, the drive output system includes the planetary gear unit 13, the generator 16, the first counter drive gear 15, the counter driven gear 32, the second counter drive gear 27, the counter shaft 31, the differential pinion gear 33, It is composed of a differential ring gear 35 and a differential device 36.

As described above, not only the rotation generated by the engine 11 can be transmitted to the counter driven gear 32, but also the rotation generated by the electric motor 25 can be transmitted to the counter driven gear 32. The hybrid vehicle can be run in an engine drive mode that drives only 11, an electric motor drive mode that drives only the electric motor 25, and an engine-motor drive mode that drives the engine 11 and the electric motor 25. Further, by controlling the electric power generated in the generator 16, the rotation speed of the transmission shaft 17 can be controlled. When the rotation of the generator is stopped, the brake B can be engaged to fix the rotor 21 of the generator 16. In this case, by releasing the engagement of the brake B, it is possible to set the mode in which the generator 16 travels while generating power in the brake released state and the mode in which the generator 16 runs without generating power in the brake engaged state. .

The operation of the planetary gear unit 13 of the hybrid vehicle having the above structure will be described. FIG. 2 (A)
Is the planetary gear unit 1 according to the first embodiment of the present invention.
3 (FIG. 1) is a conceptual diagram, FIG. 2 (B) is a velocity diagram of the planetary gear unit 13 according to the first embodiment of the present invention during normal traveling, and FIG. 3 is a planetary gear unit according to the first embodiment of the present invention. FIG. 13 is a torque diagram of No. 13 during normal traveling.

In this embodiment, as shown in FIG. 2A, the number of teeth of the ring gear R of the planetary gear unit 13 is twice the number of teeth of the sun gear S.
Therefore, the unit output shaft 14 connected to the ring gear R
NR is the number of rotations of the
Let NE be the rotational speed of the engine output shaft 12 connected to the carrier CR (hereinafter referred to as "engine rotational speed"), and NE be the rotational speed of the transmission shaft 17 connected to the sun gear S (hereinafter referred to as "generator rotational speed"). .) Is NG, NR, N
The relationship between E and NG is, as shown in FIG.

NG = 3.NE-2.NR

## EQU1 ## Further, the torque output from the ring gear R to the unit output shaft 14 (hereinafter referred to as "ring gear torque") is TR, the torque of the engine 11 (hereinafter referred to as "engine torque") is TE, and the generator torque is TG. Then, the relationship between TR, TE and TG is as shown in FIG.

TE: TR: TG = 3: 2: 1

## EQU1 ## During normal traveling of the hybrid vehicle, ring gear R, carrier CR and sun gear S are all rotated in the positive direction, and
As shown in (B), the ring gear rotation speed NR (= output rotation speed NOUT), the engine rotation speed NE, and the generator rotation speed NG all take positive values.

Then, the engine torque TE is input to the carrier CR, and the engine torque TE is received by the reaction force of the first counter drive gear 15 and the generator 16 shown in FIG. As a result, as shown in FIG. 3, from the ring gear R to the unit output shaft 14
The ring gear torque TR from the sun gear S to the transmission shaft 17
The generator torque TG is output to.

The ring gear torque TR and the generator torque TG are obtained by apportioning the engine torque TE by the torque ratio determined by the number of teeth of the planetary gear unit 13, and on the torque diagram, the ring gear torque TR and the generator. The engine torque TE is obtained by adding the torque TG.

Next, the control system of the hybrid vehicle of the present invention will be described in detail with reference to the block diagram of FIG. The control means constituting the control system of the present embodiment includes a vehicle control device 41, an engine control device 42, a motor control device 43, and a generator control device 44. These control devices 41, 42, 43, 44 are, for example, CPUs.
(Central processing unit), ROM (read only memory) in which various programs and data are stored, RAM (random access memory) used as a working area, and the like can be configured by a microcomputer.

Further, this control system includes an accelerator sensor 45 for detecting an accelerator opening α indicating the driver's demand for vehicle driving force, a vehicle speed sensor 46 for detecting a vehicle speed v, and a brake. A brake sensor 47 that detects a stepping amount β and a battery sensor 4 that is a charge capacity detection unit that detects a charge capacity of a capacitor 19 that is a power storage unit.
8 is provided. Each sensor 45, 46, 4
The detection values detected at 7 and 48 are supplied to the vehicle control device 41.

The vehicle control device 41 controls the entire hybrid vehicle and performs the following control. Determination of motor torque command value TM * The accelerator opening α supplied from the accelerator sensor 45,
A torque corresponding to the vehicle speed v supplied from the vehicle speed sensor 46 is determined, and this is supplied to the motor control device 43 as a motor torque command value TM *. In addition, the torque fluctuation caused by the rotation speed control of the generator 16 described later causes the electric motor 2
5 is absorbed by correcting the output torque TM, the correction torque ΔTM for this correction is calculated by the vehicle control device 41, and the motor torque command value TM * corrected by the correction torque ΔTM is used as the motor control. It is supplied to the device 43. The vehicle control device 41 and the motor control device 43 constitute torque correction means.

Determination of Target Charging Rate (Target Voltage) of Capacitor and Control of Charging Amount of Capacitor The vehicle control device 41 acts as a changing means for changing the target charging rate of the charging means. The target charge rate of the capacitor 19 is obtained from the vehicle speed v based on the map shown in FIG. That is, when is a vehicle speed v ₀ traveling vehicle, since it has a motion Erunegi proportional to the square of the vehicle speed v _0, which is decelerated with a regenerative braking from the vehicle speed v _0,
The amount of kinetic energy that has been decelerated to the maximum can be recovered as regenerative electric power, and the capacitor 19 needs to have a margin as the remaining storage capacity that is sufficient to recover the regenerated electric power. That is, the control target value is a charge rate that has a charge rate enough to supply sufficient driving power to the electric motor 25 when starting or traveling at low speed, and has a remaining charge capacity that can recover regenerative power during deceleration. The target value is appropriately changed based on the vehicle speed v, the accelerator opening α, and the like. Specifically, it is determined as follows. Capacitor 19
If the maximum stored energy of is Emax, the target stored energy Et is expressed by the following equation.

Et = Emax- (1/2 · M · v ₀ ² ) · η · k (1)

Here, M is the mass of the vehicle, η is the loss rate when converting into electric energy, and k is the conversion constant when converting from kinetic energy into electric energy. On the other hand, in order to secure the drive of the electric motor 25, it is necessary to secure a constant amount of electricity storage Emin at all times, and the relationship between these is shown in the diagram as shown in the map in FIG. . By thus setting the lower limit value of the amount of stored electricity, a stable supply of electric power is always ensured and stable running of the vehicle is ensured. The remaining amount of energy of the capacitor 19 is proportional to the square of the output voltage Vc. Therefore, the energy Ec stored in the capacitor 19 is expressed by the following equation.

Ec = 1/2 · C · Vc ² ... Formula (2)

Here, C is a storage capacity. The above relationship is represented in the diagram as shown in the map of FIG. From the formula (2), Emax = 1/2 · C · Vmax
² , Et = 1 / 2CVt ² , and the following equation is obtained from the equation (2) and the equation (1).

1/2 · C · Vmax ² = (1/2 · M · v ₀ ² ) · η · k + 1/2 · C · Vt ² (3)

That is, this relationship is a diagram obtained by adding FIG. 7 to FIG. 6, and becomes the map shown in FIG. Based on the map of FIG. 5, the vehicle control device 41 calculates the target voltage Vt at that time from the vehicle speed v. In the present embodiment, a capacitor is used as the power storage means, and the output voltage Vc is determined according to the amount of stored power. Therefore, the output voltage Vc of the capacitor 19 (hereinafter referred to as “capacitor voltage”) Vc is used as the stored energy and is to be controlled. You can Therefore,
The battery sensor detects the output voltage of the capacitor and supplies the detected value to the vehicle control device 41. Then, the vehicle control device 41 obtains the target voltage Vt instead of the target charge rate, and the capacitor voltage Vc becomes the target voltage Vt,
The generator rotation speed NG is controlled to adjust the electric power charged in the capacitor 19. The vehicle control device 41 and the generator control device 44, or further, the motor control device 43 configures a power storage amount control means, and particularly, the vehicle control device 41 and the generator control device 44 configure the generator control means. .

Control of Engine The error Vd between the target voltage Vt obtained by the above control and the capacitor voltage Vc, and the accelerator opening α at that time
From the above, the engine speed-increasing rotation speed ΔNE is determined based on the map shown in FIG. 8, the engine rotation speed NE is determined based on the determined value, and the engine 11 is controlled so as to attain the rotation speed. In addition, since the generator speed-up speed ΔNG, which will be described later, which is obtained from ΔNE, becomes small and the control efficiency deteriorates, ΔNE is not satisfied in the range of −500 <ΔNE <500.
= 0. Further, the vehicle control device 41 supplies an engine ON / OFF signal to the engine control device 42. Specifically, for example, the ignition key is turned ON /
Depending on the OFF state, the engine throttle ON / OFF signal is supplied. It is also possible to turn on / off the engine or open / close the throttle during traveling without depending on the on / off of the ignition.

Control of Generator The control target speed NG * of the generator 16 is supplied to the generator control device 44. The generator rotational speed NG is determined by the engine speed-up rotational speed ΔNE, the error voltage Vd, and the accelerator opening α.
The control target speed NG * is determined according to the generator speed-up speed ΔNG obtained from

Control of Brake B The vehicle control device 41 supplies an ON / OFF signal to the electromagnetic valve 54 that operates the brake B. Solenoid valve 54
Is operated by a solenoid incorporated in the electromagnetic valve 54 based on the supplied ON / OFF signal.
In the case of a signal, the solenoid operates to open the valve, and the pressure oil from the oil pump is supplied to the brake actuator to bring the brake B into the engaged state. In the case of an OFF signal, the valve is closed. Disengage the brake B. When controlling the number of rotations of the generator 16 to zero, the electric power for control can be saved by engaging the brake B. The brake B used in this embodiment may be any type of brake. In this case, either a wet brake or a dry brake may be used,
It is preferable to use a wet brake because the rotation speed can be easily controlled. The engagement control means includes a hydraulic circuit including an electromagnetic valve 54 and a brake actuator, and the vehicle control device 4.
And 1.

Next, another control device will be described. The engine control device 42 drives the engine 11 based on a selection command signal input from the vehicle control device 41 into a driving state (ON state) in which engine torque is output and a non-driving state in which engine torque is not generated. (OFF state)
Switch to and. In addition, the output of the engine 11 is controlled by controlling the throttle opening θ according to the actual engine speed NE input from the speed sensor provided in the engine 11. The engine speed NE is supplied to the vehicle control device 41.

The motor control device 43 controls the current (torque) IM of the electric motor 25 so that TM = TM *. As a result, the determined torque TM * is constantly maintained. The vehicle control device 41 and the motor control device 43 constitute torque correction means. Further, the motor control device 43 monitors the actual rotation speed NM and the output torque TM of the electric motor 25, and supplies the values to the vehicle control device 41, respectively.

The generator control device 44 controls the rotation speed NG of the generator 16 and controls the current (torque) IG so that the control target rotation speed NG * input from the vehicle control device 41 is reached. Further, the generator control device 44 monitors the output torque TG of the generator 16 and the actual rotation speed NG of the generator 16, and supplies the values to the vehicle control device 41, respectively.
The vehicle control device 41 and the generator control device 44 constitute a generator control means.

Next, the operation of the vehicle control device 41 of the hybrid vehicle of the present embodiment configured as described above will be described. FIG. 9 is a flowchart showing the control operation of the vehicle control device 41. From the accelerator sensor 45, the accelerator opening α, and from the brake sensor 47, the brake depression amount β
Is detected (step S101), the vehicle speed v is detected from the vehicle speed sensor 46 (step S102), and the battery sensor 4
8 to detect the capacitor voltage Vc (step S10)
3).

Based on the map shown in FIG. 5, the target voltage Vt of the capacitor 19 corresponding to the detected vehicle speed v is obtained (step S104), and the error voltage between the obtained target voltage Vt and the detected capacitor voltage Vc. Vd (= Vt-V
c) is obtained (step S105).

Next, the torque Tc required for traveling is calculated from the detected accelerator opening α and brake depression amount β (step S106). Further, it is determined whether or not the brake depression amount β is larger than a preset threshold value βeof (step S107).

When the brake depression amount β is smaller than the threshold value βeof, the engine speed-up speed ΔNE is calculated from the error voltage Vd and the accelerator opening α based on the map in FIG. 8 (step S108), and the engine speed-up is performed. From the rotational speed ΔNE, the generator speed-up rotational speed ΔNG * (= 3 · ΔNE) is calculated to obtain the target rotational speed NG * (step S109), and this target rotational speed NG * is supplied to the generator control device 44 ( Step S110).

As a result of the rotation speed control, the torque TG of the generator 16 generated is detected from the generator (step S111),
Based on the required torque Tc obtained in step S106, the generator 1
The value obtained by correcting the torque TG of 6 is set as the output torque TM * (= Tc-3TG) of the electric motor 25 (step S1.
12) and supply to the electric motor 25 (step S11)
3).

On the other hand, if it is determined in step S107 that the brake depression amount β is larger than the threshold value βeof, the generator 16 is instructed about the rotation speed for stopping the engine (step S114). At this time, the electric motor 2
Since No. 5 is regeneratively driven, Tc has a negative value.

Next, it is determined whether the error voltage Vd has a negative value, that is, whether the target voltage Vt is smaller than the capacitor voltage Vc (step S115). Error voltage V
When d is a positive value, that is, when the capacitor voltage Vc is smaller than the target voltage Vt, the torque value Tc obtained in step S106 is set to the motor torque command value TM *.
As (= Tc) (step S116), the electric motor 2
5 (step S113).

When the error voltage Vd is a negative value, that is, when the capacitor voltage Vc is larger than the target voltage Vt, the value obtained by multiplying the torque value Tc obtained in step S106 by a coefficient r is used as the motor torque command value TM. * (= Tc · r)
As (r ≦ 1.0) (step S117), this is supplied to the electric motor 25 (step S113). As a result, the amount of regenerative electric power in the electric motor 25 is reduced, and overcharging is suppressed.

In the above control operation, the brake depression amount β
When is smaller than (threshold value βeof), the generator rotation speed is controlled, and the fluctuation of the output torque due to the change of the generator rotation speed is corrected by adjusting the motor torque.

The above description will be described with reference to the time chart shown in FIG. When the vehicle starts from the stopped state (time t ₀ ), the driving force of the electric motor 25 travels as the driving wheel output when the vehicle travels at a low speed.
The power consumption of 9 is large. Therefore, the target voltage Vt is set large and the value changes low as the vehicle speed v increases.
Acceleration even finished (time t _2), between the capacitor voltage Vc is the target voltage Vt is smaller than increases the amount of power supplied to the capacitor 19 by increasing the rotational speed of the generator 16 (time t ₀ ~t ₃₎ . Then, the target voltage Vt corresponding to the vehicle speed v
Is set. During braking, the capacitor voltage rises due to the regenerative power of the electric motor 25 (time t ₄
~t _5), since the target voltage Vt is set in anticipation of regenerative power in accordance with the advance vehicle speed v, never capacitor 19 by the regenerative electric power of the electric motor 25 is overcharged.

<Second Embodiment> Next, a second embodiment of the present invention will be described. In the second embodiment, the control operation of the vehicle control device 41 is different from that of the first embodiment. Hereinafter, the first
Only parts different from the embodiment will be described, and other configurations are the same as those in the first embodiment, and therefore description thereof will be omitted.

Since the maximum number of revolutions of the electric motor 25 is almost proportional to the power supply voltage, it is preferable to keep the charged amount high and increase the voltage during high speed running. That is, in the case of the present embodiment, the capacitor voltage Vc and the maximum rotation speed R of the motor
The relationship with max is Rmax = k · Vc (k is a proportional constant depending on the design parameter of the motor), which is shown in the map of FIG. 11. On the other hand, since the vehicle speed v is proportional to the rotation speed of the motor, the relationship between the target voltage Vt and the vehicle speed v is expressed as Vt =
h · v (h is a proportional constant), and when this is overlaid on the map of FIG. 5, it becomes the map shown in FIG. 12.

That is, the target voltage Vt is the required output voltage V of the capacitor for a preset speed, that is, the vehicle speed.
In a speed range (high speed range) in which c is equal to or higher than the value of the target voltage Vt shown in FIG. 5, in order to guarantee acceleration from a high vehicle speed, it is set high according to an increase in vehicle speed, In other areas, the regenerative electric power generated during deceleration is taken into consideration so that it is set to be lower as the vehicle speed v increases, and in the low speed range, in order to prepare for acceleration from a low speed, Set high. Therefore, as shown in FIG. 13, even when the vehicle resistance is accelerated during high-speed traveling (point a) and the traveling resistance exceeds the engine power generation output, energy shortage is unlikely to occur because the capacitor voltage Vc is sufficient. Become.

As described above, in the second embodiment, only the control operation for setting the target voltage Vt is different, and the other control operations are performed in the same manner as the flowchart shown in FIG.

<Third Embodiment> FIG. 14 is a conceptual diagram of a so-called series hybrid vehicle. This hybrid vehicle includes an engine 71 and a generator 72 that generates electric power by rotating a rotor with a driving force output from the engine 71.
And a storage means 73 for storing the electric power generated by the generator 72
And an electric motor 74 which is driven by receiving driving power from the power storage means 73, and a drive wheel 75 which is rotated by the driving force of the electric motor 74. In this embodiment, since the amount of power generation can be arbitrarily adjusted regardless of the traveling state, the amount of power storage of the power storage unit can be easily adjusted to the target amount of power storage. That is, the throttle opening of the engine 71 can be adjusted to adjust the rotation speed of the engine 71, or the amount of electricity stored in the electricity storage unit can be adjusted by stopping the engine 71.

<Fourth Embodiment> FIG. 15 is a conceptual diagram of a so-called parallel hybrid vehicle. This hybrid vehicle includes an engine 81, an electric motor 82, a clutch 83 that connects the output of the engine 81 and the output of the electric motor 82, a storage unit 84 that supplies drive power to the electric motor 82, the engine 81 and the electric motor 82. Drive wheels 85 that are rotated by the drive force transmitted from the.

In the clutch ON state, the driving force of the engine 81 and the electric motor 82 is transmitted to the drive wheels 85, and in the clutch OFF state, only the driving force of the electric motor 82 is transmitted to the drive wheels 85. Also, during deceleration, the electric motor 82
The electric power regenerated by is supplied to the storage means 84. In this embodiment, the amount of electricity stored can be adjusted by adjusting the throttle opening of the engine 81, turning the clutch ON / OFF, cutting the fuel of the engine 81, changing the gear position of the transmission connected to the engine 81, and the like. Become. Further, when an engine torque exceeding a running resistance such as a drag resistance and an air resistance during running is generated, the electric motor 82 can be regeneratively driven by the extra engine torque to store electricity. .

In each of the embodiments described above, other storage means other than the capacitor can be used as the storage means. Examples include secondary batteries, flywheel batteries, hydraulic (pneumatic) accumulators, and the like. Examples of secondary batteries include lead storage batteries and alkaline storage batteries. Specifically, lead batteries, nickel-cadmium batteries,
Examples include nickel / iron batteries, nickel / zinc batteries, and lithium batteries. The remaining storage capacity is the output integrated value (k
wh, Ah), open circuit voltage, IV characteristic, etc.

The flywheel battery is a power storage means that transfers electric power by driving and regenerating the flywheel with a motor arranged coaxially with the flywheel. The remaining storage capacity can be detected by the rotation speed of the flywheel.

The oil (pneumatic) pressure accumulator is a power storage means for transmitting and receiving electric power by taking oil (pneumatic) pressure in and out of the accumulator by means of an oil (pneumatic) pressure pump connected to the accumulator. The remaining storage capacity can be detected by the oil (pneumatic) pressure value.

[0073]

The invention according to claim 1 described above is
By changing the target storage rate according to the running state,
Since energy loss due to over-charge and over-discharge is suppressed,
It is possible to improve the efficiency of the entire hybrid vehicle and reduce deterioration of the power storage unit itself. further,
Since the power storage means can be used efficiently, it is possible to use a power storage means having a smaller storage capacity than before, and it is possible to reduce the weight and size of the entire vehicle.

According to the second aspect of the present invention, the target charge rate is decreased in response to the increase in vehicle speed, so that the overcharge of the charge means due to the regenerative electric power caused by the deceleration is suppressed.

According to the third aspect of the present invention, by controlling the number of revolutions of the generator, the charge rate of the power storage means can be finely controlled, and further higher energy efficiency can be obtained. The life can be extended further.

According to the fourth aspect of the invention, by providing the torque correction means for correcting the torque fluctuation due to the generator speed control, the fluctuation of the torque transmitted to the drive wheels can be suppressed, and the shock is small. A good driving feeling can be secured.

According to the fifth aspect of the present invention, when a capacitor is used as the power storage means, the target charging rate is set to be high in response to an increase in vehicle speed during high speed traveling, so that acceleration during high speed traveling can be achieved. Sufficient driving power can be supplied to it.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a drive device for a hybrid vehicle in a first embodiment of the present invention.

FIG. 2 is a conceptual diagram and a velocity diagram of a planetary gear unit according to the first embodiment of the present invention.

FIG. 3 is a torque diagram of the planetary gear unit according to the first embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a control system in the first embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a relationship between a vehicle speed and a target voltage of the hybrid vehicle according to the first embodiment of the present invention.

FIG. 6 is a target stored energy Et determined in consideration of only the kinetic energy of the vehicle in the first embodiment of the present invention.
It is a map showing the relationship between the vehicle speed and.

FIG. 7 is a map showing the relationship between the capacitor voltage and the stored energy of the capacitor in the first embodiment of the present invention.

FIG. 8 is a relationship diagram for obtaining an engine speed-up rotation speed in the first embodiment of the present invention.

FIG. 9 is a flowchart showing a control operation of the vehicle control device according to the first embodiment of the present invention.

FIG. 10 is a time chart showing a control operation of the vehicle control device according to the first embodiment of the present invention.

FIG. 11 is a relationship diagram showing the relationship between the capacitor voltage and the maximum motor rotation speed in the second embodiment of the present invention.

FIG. 12 is an explanatory diagram showing a relationship between a vehicle speed and a target voltage of a hybrid vehicle according to a second embodiment of the present invention.

FIG. 13 is a relationship diagram showing a relationship between vehicle speed and engine power generation output of the hybrid vehicle in the second embodiment of the present invention.

FIG. 14 is a conceptual diagram showing a configuration of a third exemplary embodiment of the present invention.

FIG. 15 is a conceptual diagram showing a configuration of a fourth exemplary embodiment of the present invention.

FIG. 16 is a time chart showing changes in the charge amount in the conventional charge amount control method.

[Explanation of symbols]

11 Engine 13 Planetary Gear Unit (Differential Gear Device) 16 Generator 19 Capacitor (Power Storage Means) 21 Rotor 25 Electric Motor 31 Counter Shaft (Drive Output Shaft) 41 Vehicle Control Device 42 Engine Control Device 43 Motor Control Device 44 Generator Control Device 45 accelerator sensor 46 vehicle speed sensor 47 brake sensor 48 battery sensor 54 electromagnetic valve B brake CR carrier (first gear element) S sun gear (second gear element) R ring gear (third gear element)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B60L 11/14 B60K 9/00 Z H02J 7/14

Claims (5)

[Claims] 1. An engine, an electric motor that outputs a driving force to driving wheels, a power storage unit that supplies driving power to the electric motor, a vehicle speed detection unit that detects a vehicle speed, and a power storage unit that stores the vehicle speed according to the detected vehicle speed. A hybrid vehicle, comprising: a changing unit that changes a target charge rate of the unit, and a charge amount control unit that controls the electric power supplied to the charge unit to reach the target charge rate. 2. The hybrid vehicle according to claim 1, wherein the changing unit reduces the target charge rate of the power storage unit in response to an increase in vehicle speed. 3. A generator with controllable rotation speed, a first gear element on the output shaft of the engine, a second gear element on the rotor of the generator, and a third gear element on the drive. A differential output device connected to a drive output shaft for transmitting a driving force to a wheel, wherein the storage amount control means controls the rotation speed of the generator according to the target storage rate. Claim 1
Alternatively, the hybrid vehicle described in 2. 4. The hybrid vehicle according to claim 3, further comprising a torque correction unit that corrects a motor output torque of the electric motor according to a torque fluctuation generated by the rotation speed control by the generator control unit. 5. The power storage means has a capacitor, and in a region where a required output voltage of the capacitor with respect to a vehicle speed is higher than an output voltage at the target charge rate, the target charge rate is set high according to an increase in the vehicle speed. The hybrid vehicle according to any one of claims 1 to 4.