JP2000346187A - Hybrid vehicle and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve operating efficiency of a hybrid vehicle. SOLUTION: A motor 130 is connected to a sun gear 121 of a planetary gear 120, a drive shaft 112 and an assist motor 140 are connected to a ring gear 124, and an engine 150 is connected to a planetary carrier 123 through a planetary gear 200 constituting a speed change mechanism. Power output from the engine 150 is distributed into two parts by the planetary gear 120, while regenerating partly the power as the electric power in the motor 130, the rest of the power is output to the drive shaft 122. The regenerated power is supplied to the assist motor 140, and torque output to the drive shaft is added. In accordance with a running condition of a vehicle, speed change ratio is controlled so as to decrease a difference between input/output rotational speeds of the planetary gear 120. As the result, regenerative electric power at torque change time can be suppressed, a loss according to the conversion between power and electric power can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel hybrid vehicle that can run using at least an engine as a power source.

[0002]

2. Description of the Related Art In recent years, a hybrid vehicle using an engine and an electric motor as power sources has been proposed (for example, Japanese Unexamined Patent Publication No.
-47094). As one type of hybrid vehicle, there is a so-called parallel hybrid vehicle. The parallel hybrid vehicle travels by converting the number of revolutions and torque of the engine into the target number of revolutions and torque through the conversion of power and electric power by the torque conversion means and outputting the target number of revolutions and torque to the drive shaft. As the torque conversion means, a configuration including a power adjustment device that transmits power while adjusting power by exchanging power and an electric motor is applied. A part of the power output from the engine is transmitted to the drive shaft by the power adjusting device, and the remaining power is regenerated as electric power. This electric power is stored in a battery or used to drive an electric motor as a power source other than the engine. The parallel hybrid vehicle can output the power output from the engine to the drive shaft at an arbitrary rotation speed and torque, and the engine selects a driving point with high operating efficiency regardless of the required power to be output from the drive shaft. The fuel economy and exhaust gas purifying properties are excellent because the vehicle can be driven.

[0003]

In the above-structured parallel hybrid vehicle, torque conversion is performed through conversion between electric power and motive power. The conversion between electric power and motive power usually involves a certain loss. Due to such a loss, the conventional parallel hybrid vehicle cannot maintain a sufficiently high driving efficiency in the entire operable driving range.
For example, in a high-speed operation region or an operation region requiring high torque, the operation efficiency may be reduced.

[0004] Further, in a conventional hybrid vehicle, power is circulated during torque conversion, and the driving efficiency is sometimes reduced. The circulation of power will be specifically described. FIG. 22 is an explanatory diagram showing a schematic configuration of a hybrid vehicle in which an electric motor is connected to a drive shaft. Here, the case where the planetary gear PG and the generator G are applied as the power adjusting device is shown. The planetary gear PG is also called a planetary gear,
It consists of a sun gear that rotates at the center, a planetary pinion gear that revolves while rotating around its periphery, and a ring gear that rotates around its outer periphery. The planetary pinion gear is supported by a planetary carrier. As is well known, the planetary gear PG has a mechanical property such that when the rotational state of two of the three elements of the sun gear, the planetary carrier, and the ring gear is determined, the rotational state of the remaining elements is determined. ing. Based on such properties, the planetary gear PG can distribute and transmit the power input to one element to the other two elements. FIG.
In the configuration exemplified in (1), the generator G is coupled to the sun gear,
The engine EG is connected to the planetary carrier, and the electric motor AM and the drive shaft DS are connected to the ring gear. The planetary gear PG, the generator G, and the electric motor AM constitute a torque converter TC. In such a configuration, there is a characteristic that the driving efficiency is increased during underdrive running in which the rotation speed of the drive shaft is lower than the rotation speed of the engine.

FIG. 23 is an explanatory diagram showing how power is transmitted in a hybrid vehicle in which an electric motor is connected to a drive shaft when the engine speed is higher than the drive shaft speed. The power output from the engine EG is output from the drive shaft DS while reducing the rotation speed and increasing the torque. The power PU1 output from the engine EG is
The two are distributed by the planetary gear PG, and a part is transmitted as the power PU2 whose rotational speed and torque are reduced. The remaining part is transmitted to the generator G. When the generator G is driven by this power, power is generated, and a part of the power output from the engine EG is regenerated as power EU1. This power EU1 allows the assist motor AM
, And compensates for the insufficient torque, whereby the power PU3 having the required rotation speed and torque is output to the drive shaft DS.

FIG. 24 is an explanatory diagram showing how power is transmitted in a hybrid vehicle in which an electric motor is connected to a drive shaft when the engine speed is lower than the drive shaft speed. The power PU1 output from the engine EG is
By driving the generator G, the speed of the power PU is increased.
4 is transmitted from the planetary gear PG to the downstream side.
Next, a load is applied by the assist motor AM to reduce the excess torque, so that the power PU3 having the required rotation speed and torque is output to the drive shaft DS. The assist motor AM applies a load by regenerating a part of the power PU4 as electric power EU2. This electric power is used for powering the generator G.

Comparing the two, when the rotation speed of the engine EG is higher than the rotation speed of the drive shaft (FIG. 23), the engine EG is located on the upstream side in the path where the power output from the engine is transmitted to the drive shaft. The electric power regenerated by the power adjusting device PG + G is supplied to the assist motor AM located on the downstream side. When the rotation speed of the engine EG is lower than the rotation speed of the drive shaft (FIG. 24), on the contrary, the power regenerated by the assist motor AM located on the downstream side is supplied to the power adjustment device PG + G located on the upstream side. You. Power adjustment device PG +
The electric power supplied to G is supplied again to the assist motor AM located on the downstream side as mechanical power. As a result, power circulation γ1 shown in FIG. 24 occurs. When the power circulation γ1 occurs, the power that is effectively transmitted to the drive shaft DS out of the power output from the engine EG decreases, so that the operating efficiency of the hybrid vehicle decreases.

On the contrary, when the motor is connected to the output shaft,
The engine, the electric motor, and the power adjusting device are connected in this order. FIG. 25 is an explanatory diagram showing a schematic configuration of a hybrid vehicle in which an electric motor is connected to an output shaft. As shown in the figure, an electric motor AM is coupled to an output shaft CS of an engine EG, and a planetary gear PG and a generator G as a power adjusting device are coupled to a drive shaft DS. Conversely, such a configuration has a characteristic that the operating efficiency is increased during overdrive traveling in which the rotational speed of the drive shaft is higher than the rotational speed of the engine.

FIG. 26 is an explanatory diagram showing how power is transmitted in a hybrid vehicle in which an electric motor is connected to an output shaft when the engine speed is higher than the drive shaft speed. FIG. 27 is an explanatory diagram showing how power is transmitted in a state where the rotation speed of the engine is lower than the rotation speed of the drive shaft in the hybrid vehicle in which the electric motor is connected to the output shaft. Regarding the transmitted power, the rotation speed can be adjusted only by the planetary gear PG. Therefore, in a hybrid vehicle in which the electric motor is connected to the output shaft, a phenomenon opposite to that in the case where the electric motor is connected to the drive shaft occurs. When the rotation speed of engine EG is lower than the rotation speed of the drive shaft (FIG. 26), electric power EO1 regenerated by power adjustment device PG + G located on the downstream side is supplied to assist motor AM located on the upstream side. Conversely, when the rotation speed of the engine EG is higher than the rotation speed of the drive shaft (FIG. 27), EO2 regenerated by the assist motor AM located on the upstream side is supplied to the power adjustment device PG + G located on the downstream side. You. Therefore, when the electric motor is connected to the output shaft of the engine, in the former case, the power circulation γ2 shown in FIG. 26 occurs, and the operating efficiency of the hybrid vehicle decreases.

As described above, in the conventional hybrid vehicle,
Power is circulated in a specific traveling region depending on the connection destination of the electric motor AM, and the operating efficiency is reduced. It is also possible to switch the connection destination of the electric motor AM between the output shaft CS and the drive shaft DS of the engine according to the driving state of the vehicle so that the power does not circulate. However, in such a case, the device configuration for realizing the switching of the coupling destination of the electric motor AM becomes complicated, and a torque shock occurs at the time of the switching, which causes new problems such as lowering the riding comfort and responsiveness of the vehicle.

SUMMARY OF THE INVENTION The present invention has been made to solve at least a part of the problems described above, and a parallel hybrid vehicle capable of outputting a part of the power from an engine directly to a drive shaft has a high performance in a wide range. It is an object of the present invention to provide a hybrid vehicle capable of realizing efficient driving.

[0012]

Means for Solving the Problems and Their Functions and Effects In order to solve at least a part of the above problems, the present invention employs the following constitutions. A hybrid vehicle according to the present invention includes an engine having an output shaft, a drive shaft for outputting power, a first rotation shaft coupled to the output shaft side, and a second rotation coupled to the drive shaft side. And a torque conversion means having a shaft and converting the number of rotations and torque of the first rotation shaft through conversion between power and electric power and capable of outputting the converted rotation and torque to the second rotation shaft. The gist of the present invention is to provide a transmission that is interposed in a path until the power output from the engine is output to the drive shaft and transmits power at a predetermined gear ratio.

The loss in the hybrid vehicle mainly occurs in the torque conversion means. In the hybrid vehicle configured as described above, the power output from the engine can be converted to torque and output to the drive shaft through the conversion between power and power. Normally, a predetermined energy loss occurs in the conversion between electric power and power. If this energy loss increases,
The driving efficiency of the hybrid vehicle decreases.

When the rotational speed and torque of the power (hereinafter referred to as direct power) mechanically transmitted from the engine to the drive shaft match the target rotational speed and target torque to be output to the drive shaft, the torque No conversion is required. in this case,
Since the conversion between electric power and motive power is not performed, the operation efficiency is high. On the other hand, when the rotation speed and the torque of the direct power are different from the target rotation speed and the target torque of the drive shaft,
It performs torque conversion through conversion between electric power and motive power. That is,
While part of the power output from the engine is output to the drive shaft as mechanical direct power, the remaining power is temporarily replaced with electric power. This electric power is used to drive a motor provided inside the torque conversion means, to compensate for the difference between the direct power and the target power of the drive shaft, and to output the power consisting of the target rotation speed and the target torque to the drive shaft. If the difference between the direct power and the target power of the drive shaft increases, the amount of conversion between power and power increases, and the loss that occurs during conversion also increases. As a result, the driving efficiency of the hybrid vehicle decreases.

According to the hybrid vehicle of the present invention, the difference between the direct power and the target power of the drive shaft can be suppressed by the operation of the transmission. Consider a running state in which the rotation speed of the direct power is much smaller than the rotation speed of the target power, and the torque converter needs to increase the speed. In such a case, according to the hybrid vehicle of the present invention, the speed of the direct power from the engine can be increased by switching the transmission to the speed increasing side. The torque conversion means only needs to perform conversion for adjusting the difference between the increased direct power and the target power, so that the amount of conversion between power and power can be reduced.
In other words, the ratio of the direct power to the power output to the drive shaft can be increased. As a result, the loss generated in the torque converter can be suppressed, and the driving efficiency of the hybrid vehicle can be improved.

[0016] Even in a running state in which the rotation speed of the direct power is much higher than the rotation speed of the target power and deceleration is required by the torque conversion means, the operation efficiency can be similarly improved. In such a case, in other words, the torque of the direct power is much lower than the torque of the target power, and this corresponds to a running state in which the torque conversion unit needs to add torque. According to the hybrid vehicle of the present invention, in such a running state, the torque of the direct power from the engine can be increased by switching the gear ratio to the reduction side. Therefore, the torque conversion means only needs to perform conversion for adjusting the difference between the direct power to which torque is added and the target power, so that the amount of conversion between power and power can be reduced, and the operating efficiency of the hybrid vehicle is improved. can do.

Although it is possible to use a so-called stepless speed change mechanism for the transmission, it is desirable to use a mechanism that can change the speed at a predetermined constant gear ratio. In the hybrid vehicle, the torque conversion unit can output the engine by changing the number of revolutions output from the engine to an arbitrary number of revolutions and torque. Therefore, it is less necessary to provide a continuously variable transmission. Providing a continuously variable transmission may instead lead to new problems such as a complicated and large-sized device configuration. On the other hand, a transmission having a predetermined fixed gear ratio has a simple configuration, and therefore can be incorporated with less adverse effects such as a complicated device, an increase in size, and an increase in manufacturing cost. Also, the purpose of suppressing the conversion between electric power and motive power in the torque conversion means is as follows.
This can be sufficiently achieved by shifting at a constant speed ratio. From such a viewpoint, it is desirable that the transmission uses a mechanism capable of shifting at a predetermined constant gear ratio.

The transmission may be any type as long as it can realize a speed ratio of 2 or more. The gear ratio does not necessarily need to have both the speed reduction side and the speed increase side. For example, a transmission that can be switched between a state in which the input side and the output side of the gear ratio are directly connected, and one of either a deceleration state or a speed increase state may be used. Of course, it goes without saying that the higher the transmission ratio at which the transmission can be switched, the higher the efficiency of the operation.

In the hybrid vehicle according to the present invention, the transmission may be switched manually, but a target power setting means for setting the target power of the drive shaft by a combination of a target rotation speed and a target torque. An engine control means for operating the engine at a rotational speed and a torque set with priority on operating efficiency according to the target power; and an input rotational speed of the first rotary shaft by controlling the transmission. It is preferable to provide a transmission control means for realizing a speed ratio in which a difference between the output speed of the second rotary shaft and the output speed of the second rotary shaft falls within a predetermined range set in advance.

According to this configuration, the gear ratio of the transmission can be automatically controlled, and the hybrid vehicle can be operated with high efficiency. Further, since the transmission can be switched without placing a burden on the driver, the convenience of the hybrid vehicle can be improved. In addition, regarding the difference between the input rotation speed and the output rotation speed, the predetermined range serving as the reference for the above control is variously appropriate in accordance with the configuration of the vehicle in consideration of the traveling area of the hybrid vehicle, the target driving efficiency, and the like. You can set the value.

Further, in the hybrid vehicle according to the present invention, the transmission may determine a magnitude relationship between the input rotation speed and the output rotation speed in a traveling region of the hybrid vehicle, at least a conversion efficiency of the torque conversion means. A transmission mechanism for transmitting power at a speed ratio set within a range that can be maintained in a higher relationship, wherein the transmission control means controls the transmission to determine a magnitude relationship between the input rotational speed and the output rotational speed. Is preferably a means for maintaining the relationship on the higher conversion efficiency side.

In the torque conversion means of the hybrid vehicle,
As specifically described above with reference to FIGS. 22 to 27, power circulation occurs according to the magnitude relationship between the input rotation speed of the first rotation shaft and the output rotation speed of the second rotation shaft, and the efficiency is improved. May decrease. Power circulation occurs when the input rotation speed and the output rotation speed have a predetermined magnitude relationship according to the configuration of the torque conversion means. According to the above-described hybrid vehicle, the magnitude relationship between the input rotation speed and the output rotation speed can be maintained on the higher efficiency side in almost the entire traveling region of the vehicle, and the driving efficiency can be improved. The hybrid vehicle having the above configuration suppresses a decrease in efficiency during torque conversion. Therefore, the transmission control means only needs to maintain the magnitude relationship in a constant state in the traveling region where the torque conversion is performed. It is not always necessary to maintain the magnitude relationship even in a traveling region where torque conversion is not required.

For a hybrid vehicle that maintains the magnitude relationship between the input rotation speed and the output rotation speed, more specifically, the following mode is desirable. A first aspect is that the torque conversion unit is coupled to the first rotation shaft and the second rotation shaft,
A power adjustment device that adjusts the power of the first rotation shaft to at least a power having a different rotation speed and transmits the power to the second rotation shaft by exchanging power; and a motor coupled to the second rotation shaft. In the case of the means including: the relationship on the higher conversion efficiency side is a relationship where the input rotation speed is higher than the output rotation speed.

The first mode corresponds to the mode shown in FIG. The planetary gear PG and the generator G in FIG. 22 correspond to the above-described power adjusting device, and the assist motor AM
Correspond to the above-described electric motor. Of course, this is
It does not mean that the configuration is limited to 2. As already described with reference to FIGS. 23 and 24, in the configuration in which the electric motor is coupled to the drive shaft, power circulation occurs when the input rotation speed is lower than the output rotation speed. In a first aspect,
Since the state where the input rotational speed is higher than the output rotational speed can be maintained, torque conversion can be performed with high efficiency.

According to a second aspect, the torque conversion means is coupled to the first rotation shaft and the second rotation shaft, and the power of the first rotation shaft is changed at least at different rotation speeds by exchanging electric power. In the case of a means including a power adjusting device that adjusts to power and transmits the power to the second rotating shaft and an electric motor coupled to the first rotating shaft, the relationship on the side where the conversion efficiency is high is the following. The input rotation speed is smaller than the output rotation speed.

The second mode corresponds to the mode shown in FIG. Of course, this does not mean that the configuration shown in FIG. 25 is limited. 26 and 27 already
As described in the above, in the configuration in which the electric motor is coupled to the drive shaft, power circulation occurs when the input rotation speed is higher than the output rotation speed. In the second aspect, since the state in which the input rotation speed is lower than the output rotation speed can be maintained, torque conversion can be performed with high efficiency.

In the hybrid vehicle of the present invention, the location where the transmission is provided can be variously selected. For example, the transmission can be provided between the output shaft and the torque converter. Further, the transmission may be provided between the torque conversion unit and the drive shaft.
Needless to say, transmissions may be provided both between the output shaft and the torque conversion means and between the torque conversion means and the drive shaft.

The former mode, that is, the transmission is connected to the engine EG
Is interposed between the output shaft and the torque conversion means, the power output from the engine EG can be shifted and input to the torque conversion means. That is, by shifting the input rotation speed side of the torque converter, the difference between the input rotation speed and the output rotation speed can be controlled within a predetermined range.

If the latter mode is adopted, that is, if the transmission is interposed between the torque conversion means and the drive shaft, the power output from the torque conversion means can be changed and output to the drive shaft. By doing so, the target rotation speed and the output rotation speed of the drive shaft can be set to different values. Therefore, according to the latter aspect, the difference between the input rotation speed and the output rotation speed can be controlled within a predetermined range by shifting the output rotation speed side of the torque conversion means.

Either of the above two embodiments may be selected. The range can be appropriately selected in consideration of the range of the torque and the number of revolutions output from the engine EG, the range of the torque and the number of revolutions required for the drive shaft, and the range of the torque and the number of revolutions allowed for the torque conversion means. For example, when a very large torque is output from the engine, it is desirable that the transmission be interposed between the engine and the torque converter to reduce the torque from the engine and input the torque to the torque converter. . It is also desirable to select a coupling portion of the transmission so as to avoid the complexity and size of the entire apparatus.

In the hybrid vehicle according to the present invention, various configurations can be applied to the transmission. For example,
The transmission can selectively rotate and stop a planetary gear of which two rotation shafts are respectively coupled to the output shaft side and the drive shaft side, and a remaining rotation shaft of the planetary gear among the three rotation shafts. And a connecting means capable of selectively connecting and releasing the two rotating shafts to each other.

The planetary gear includes a sun gear that rotates at the center, a planetary carrier having a planetary pinion gear that revolves while rotating around the outer periphery of the sun gear, and a ring gear that further rotates around the outer periphery. 3 above
The one rotating shaft means a rotating shaft respectively connected to a sun gear, a planetary carrier, and a ring gear. The term “coupled to the output shaft and the drive shaft” does not necessarily mean that the output shaft and the drive shaft are directly coupled to each other, but also includes the case where the drive shaft is coupled to the output shaft or the drive shaft via torque conversion means. . As is well known, the planetary gear has a characteristic that when the rotation state of two of these three rotation shafts is determined, the rotation state of the remaining rotation shaft is determined.

The operation of the transmission having the above configuration will be described. It is assumed that the two rotating shafts are released and the rotation of one rotating shaft of the planetary gear is stopped by the stopping means. As a result, for the two released rotation axes,
If one rotational state is determined, the other rotational state is also determined, so that both are in a state equivalent to being connected by a gear. The gear ratio of the connection is determined by the gear ratio of the planetary gear. On the other hand, consider the case where the two rotation axes are combined and the remaining rotation axes are released. At this time, the two coupled rotation shafts rotate integrally. Therefore, the output shaft side and the drive shaft side are directly connected to each other. As described above, according to the transmission having the above configuration, the two rotating shafts can be connected at a predetermined speed ratio or directly connected by operating the connecting unit and the stopping unit. Moreover, such an operation can be realized with a relatively small device configuration. Note that various modes can be selected for the coupling state of the planetary gear to the three rotation shafts.

In the hybrid vehicle according to the present invention, various structures can be applied to the torque conversion means.
For example, the torque converting means includes a generator having a rotor shaft, a planetary gear having three rotation shafts, the rotation shafts being respectively coupled to the output shaft, the drive shaft, and the rotor shaft; And an electric motor coupled to one of the rotating shaft and the second rotating shaft.

According to this configuration, the power of the first rotating shaft can be distributed and transmitted to the drive shaft and the rotor shaft based on the general operation of the planetary gear. Therefore, a part of the input power can be transmitted to the second rotating shaft while being adjusted to the target rotation speed, and the power distributed to the rotor shaft can be regenerated as electric power by the generator. Only the torque of the transmitted power is different from the target torque of the drive shaft. The difference in torque can be compensated if the motor is operated in power or regenerative mode. According to the above-described configuration, the function can function as a torque conversion unit.

Further, the torque conversion means includes a paired rotor motor having a first rotor connected to the first rotation shaft, and a second rotor connected to the second rotation shaft; The motor may be a means including an electric motor coupled to one of the first rotation shaft and the second rotation shaft.

According to the anti-rotor motor, the input power can be transmitted to the second rotating shaft while the input power is adjusted to the target rotation speed by the electromagnetic coupling between the first rotor and the second rotor. . Further, it is also possible to regenerate a part of the power as electric power by relative sliding between the two. If the electric motor is operated in a power running operation or a regenerative operation, the difference between the torque of the transmitted power and the target torque can be compensated.
According to the above-described configuration, the function can function as a torque conversion unit.

The present invention can be configured as a control method for a hybrid vehicle in addition to the hybrid vehicle. That is, a control method according to the present invention includes an engine having an output shaft, a drive shaft for outputting power, a first rotation shaft connected to the output shaft side, and a second rotation shaft connected to the drive shaft side. Torque converting means having a rotating shaft for converting the number of rotations and torque of the first rotating shaft through the conversion between power and electric power and capable of outputting the converted rotation and torque to the second rotating shaft; And a transmission that transmits the power at a predetermined gear ratio in a path until the generated power is output to the drive shaft. Setting a target power of the drive shaft by a combination of a target rotation speed and a target torque; and (b) operating the engine at a rotation speed and a torque set in accordance with the target power with priority given to operating efficiency. (C) the input rotation of the first rotation axis; The difference between the output speed of the number of the second rotary shaft, so that a preset within a predetermined range, a control method and a step of controlling the speed ratio of the transmission.

According to such a control method, the vehicle can be operated with high efficiency in a wide operating range by the same operation as described above for the hybrid vehicle. It is needless to say that, in the above control method, various additional elements described above for the hybrid vehicle can be printed.

[0040]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples. (1) Configuration of Embodiment: First, the configuration of the embodiment will be described with reference to FIG. FIG. 1 is an explanatory diagram showing a schematic configuration of the hybrid vehicle of the present embodiment. The power system of this hybrid vehicle has the following configuration. Engine 150 provided in the power system is a normal gasoline engine, and rotates crankshaft 156. The operation of the engine 150 is controlled by the EFIECU 170. The EFIECU 170 has a CPU, ROM, R
This is a one-chip microcomputer having an AM and the like, and a CPU executes a fuel injection charge of the engine 150 and other controls according to a program recorded in a ROM. In order to enable these controls, various sensors indicating the operating state of the engine 150 are connected to the EFIECU 170. One of them is a rotation speed sensor 152 for detecting the rotation speed of the crankshaft 156. Illustration of other sensors and switches is omitted. EF
The IECU 170 is also electrically connected to the control unit 190, and exchanges various information with the control unit 190 by communication. EFIECU17
0 controls the engine 150 in response to various command values relating to the operating state of the engine 150 from the control unit 190.

The engine 150 is connected to a planetary gear 200 constituting a transmission mechanism. Planetary gear 2
Reference numeral 00 denotes a sun gear 201 that rotates at the center, a planetary pinion gear 202 that revolves while rotating around the center, and a ring gear 204 that rotates around the sun gear 201. Planetary pinion gear 202
Are supported by a planetary carrier 203. Crankshaft 156 is connected to planetary carrier 203. The planetary gear 2
The 00 sun gear 201 is provided with a brake 220 for stopping its rotation. Further, a clutch 210 for connecting and releasing the planetary carrier 203 and the ring gear is also provided. Clutch 210,
ON / OFF of the brake 220 is controlled by the control unit 190. The operation of the transmission mechanism will be described later. The ring gear shaft 205, which is the rotation shaft of the ring gear 204, is provided further downstream in the path through which the power output from the engine 150 located on the upstream side is transmitted, and is connected to the planetary gear 120 constituting the power adjusting device. .

The planetary gear 120 includes the sun gear 12
1. Planetary pinion gear 122, ring gear 124
And three types of gears. The planetary pinion gear 122 is supported by a planetary carrier 123. The ring gear shaft 205 is connected to the planetary carrier 12.
3. The sun gear 201 has a motor 13
0 is connected. The ring gear 204 is connected to the assist motor 140 and the drive shaft 112, and is further connected to the axle 116 having drive wheels via a differential gear 114.

The motor 130 is configured as a synchronous motor generator, and includes a rotor 132 having a plurality of permanent magnets on its outer peripheral surface, and a stator 133 around which a three-phase coil for forming a rotating magnetic field is wound. The motor 130 is the rotor 1
32 and the magnetic field by the permanent magnet provided in the stator 133
Operates as a motor driven to rotate by interaction with a magnetic field formed by the three-phase coil provided in the motor. In some cases, the interaction generates an electromotive force at both ends of the three-phase coil wound around the stator 133. It also operates as a power generator. Note that the motor 130 has a rotor 132
It is also possible to apply a sine-wave magnetized motor in which the magnetic flux density between the motor 133 and the stator 133 is sinusoidally distributed in the circumferential direction. However, in this embodiment, the non-sinusoidal magnetized motor capable of outputting a relatively large torque is used. A motor was adopted.

The stator 133 of the motor 130 is electrically connected to a battery 194 via a drive circuit 191. The drive circuit 191 is a transistor inverter including a plurality of transistors as switching elements inside, and is electrically connected to the control unit 190. When the control unit 190 PWM-controls the on / off time of the transistor of the drive circuit 191, a three-phase alternating current using the battery 194 as a power source flows to the stator 133 of the motor 130. A rotating magnetic field is formed in the stator 133 by the three-phase alternating current, and the motor 130 rotates.

The assist motor 140 is also configured as a synchronous motor generator like the motor 130, and has a rotor 142 having a plurality of permanent magnets on its outer peripheral surface and a stator 143 around which a three-phase coil for forming a rotating magnetic field is wound. And
The assist motor 140 is connected to a battery 194 via a drive circuit 192. The drive circuit 192 is also configured by a transistor inverter, and the control unit 1
90 is electrically connected. When the transistor of the drive circuit 192 is switched by the control signal of the control unit 190, a three-phase alternating current flows through the stator 143 to generate a rotating magnetic field, and the assist motor 140 rotates. In this embodiment, a non-sinusoidal wave magnetized motor is used as the assist motor 140.

The operating state of the hybrid vehicle of this embodiment is controlled by the control unit 190. The control unit 190 also has a CPU,
ROM, a one-chip microcomputer having a RAM, etc., according to a program recorded in the ROM,
The CPU is configured to perform various control processes described later. To enable these controls, various sensors and switches are electrically connected to the control unit 190. The sensors and switches connected to the control unit 190 include an accelerator pedal position sensor 16 for detecting the operation amount of the accelerator pedal.
5. A rotation speed sensor 117 for detecting the rotation speed of the axle 116
And the like. The control unit 190 is an EFI ECU
170 is also electrically connected to the EFIECU 17
Various types of information are exchanged with the device 0 through communication. By outputting information necessary for control of engine 150 from control unit 190 to EFIECU 170,
Engine 150 can be controlled indirectly. Conversely, information such as the number of revolutions of the engine 150 is
You can also enter from 0.

In the hybrid vehicle according to the present embodiment, when the on / off state of the clutch 210 and the brake 220 constituting the transmission mechanism is changed, the speed ratio when the engine 150 is coupled to the planetary gear 120 is changed by the action of the planetary gear 200. be able to. FIG. 2 is an explanatory diagram showing the operation of the transmission mechanism. Four combinations realized by turning on / off the clutch 210 and turning on / off the brake 220 are shown. The clutch 210
The on / off of the brake 220 is controlled by the control unit 19.
Controlled by 0.

First, general properties of the planetary gear 200 will be described to explain the operation of the transmission mechanism.
It is well known mechanically that the planetary gear 200 satisfies the following relationship between the rotation speed and the torque of the rotating shaft coupled to each of the sun gear 201, the planetary carrier 203, and the ring gear 204. That is, the above 3
When the power states of two rotating shafts of one rotating shaft are determined, the power states of the remaining one rotating shaft are determined based on the following relational expression. Ns = (1 + ρ) / ρ × Nc−Nr / ρ; Nc = ρ / (1 + ρ) × Ns + Nr / (1 + ρ); Nr = (1 + ρ) Nc−ρNs; Ts = Tc × ρ / (1 + ρ) = ρTr; Tr = Tc / (1 + ρ); ρ = number of teeth of sun gear 201 / number of teeth of ring gear 202 (1);

Here, Ns is the rotation speed of the sun gear 201;
Ts is the torque of the sun gear 201; Nc is the rotation speed of the planetary carrier 203; Tc is the planetary carrier 203
Nr is the number of revolutions of the ring gear 204; Tr is the torque of the ring gear 204.

The speed change mechanism can change the speed ratio based on the above-described properties of the planetary gear 200 as described below. In the upper left part of FIG. 2, a state in which both the clutch 210 and the brake 220 are turned on is shown as the coupling state A. Since the brake 220 is on, the rotation of the sun gear 201 is stopped, and the number of rotations becomes zero. Also, since the clutch 210 is on,
The ring gear 204 and the planetary carrier 203 are connected, and both rotate integrally. As a result, the above equation (1)
As is clear from the above, if the value 0 is substituted for Ns, and Nc = Nr, the rotational speeds of all the gears of the planetary gear 200 become 0. Therefore, the vehicle cannot travel in the coupled state A.

At the upper right, the clutch 2
10 shows the coupled state when the brake 220 is turned on and the brake 220 is turned on. Since the brake 220 is on, the rotation speed Ns of the sun gear 201 is zero. on the other hand,
Since the clutch 210 is off, the ring gear 2
04 and the planetary carrier 203 can rotate at different rotation speeds. As is apparent from substituting the value 0 for Ns in the above equation (1), the relationship between the rotation speed Nr of the ring gear 204 and the rotation speed Nc of the planetary carrier 203 is expressed as "Nr =
(1 + ρ) Nc ”. That is, the engine 150
Is increased to 1 + ρ times the number of revolutions and the planetary gear 120
Is equivalent to being connected to

FIG. 3 is an explanatory view schematically showing a connected state equivalent to the case where the clutch 210 is turned off and the brake 220 is turned on. In an equivalent configuration, as shown, engine 150 is coupled to planetary gear 120 via fixed transmission gears TG1 and TG2. Transmission gear T
The gear ratio of G1 and TG2 is “1 / (1 + ρ)”. That is, as described above, the rotation speed of the engine 150 is “1+
The speed is increased by ρ ”and transmitted to the planetary gear 120. Conversely, the torque is multiplied by “1 / (1 + ρ)” and transmitted to the planetary gear 120. In the following description, the connection state B is referred to as a speed-up connection state.

The lower left portion of FIG. 2 shows a connection state in which the clutch 210 is turned on and the brake 220 is turned off, as connection state C. Since the brake 220 is off, the sun gear 201 can rotate freely. On the other hand, since the clutch 210 is on, the ring gear 204 and the planetary carrier 203 rotate integrally. Unlike the connection state A, since the rotation of the sun gear 201 is not stopped, the rotation of the ring gear 204 and the planetary carrier 203 is not hindered. Therefore, in the coupled state C, the engine 150 is connected to the planetary gear 1.
This corresponds to a state directly connected to 20. FIG. 4 shows the clutch 210
FIG. 4 is an explanatory diagram schematically showing a combined state equivalent to a case where the brake is turned on and a brake is turned off. In an equivalent configuration, as shown, the engine 150 is connected to the planetary gear 1.
Directly connected to 20. In the following description, the connection state C is referred to as a direct connection state.

The lower right part of FIG. 2 shows, as a connection state D, a connection state when both the clutch 210 and the brake 220 are turned off. Since the brake 220 is off, the sun gear 201 can rotate freely. In addition, since the clutch 210 is also released, the planetary carrier 203 and the ring gear 204 can rotate at different rotation speeds. In such a state, even if the rotation state of one of the planetary carrier 203 and the ring gear 204 is determined, the other rotation state is not determined. That is, power cannot be transmitted between the planetary carrier 203 and the ring gear 204. This corresponds to a state in which engine 150 is disconnected from planetary gear 120.

As described above, the transmission mechanism includes the clutch 210
And the brake 220 can be turned on and off to obtain four types of coupling states. However, as described above, the engine 150
Power can be transmitted to the planetary gear 120 from the coupling state B (increased coupling state) and the coupling state C (directly coupled state). Therefore, in the present embodiment, these two coupling states are properly used according to the traveling state of the vehicle.

In the hybrid vehicle of this embodiment, the range in which the engine 150 can be operated is limited according to the vehicle speed due to the mechanical limitation of the planetary gear 120. Such a restriction is called a differential speed restriction. Hereinafter, the reason why the speed difference limitation occurs and the range thereof will be described.

FIG. 5 is an explanatory diagram showing the rotation state of the planetary gear 120. It is a figure called an alignment chart. The number of revolutions of each gear of the planetary gear 120 is calculated by the equation (1) shown above.
It is represented by As is clear from equation (1), the rotational speeds of the gears are in a proportional relationship. Accordingly, the sun gear 121 is shown on the horizontal axis.
(S), coordinates corresponding to the planetary carrier 123 (C) and the ring gear 124 (R) are set such that the distance between the SC and the distance between the CRs has a relationship of 1: ρ1,
If the rotation speed of each gear is taken on the vertical axis at each coordinate, the rotation speed of each gear is represented by a straight line as shown in FIG. Here, ρ1 is the gear ratio of the planetary gear 120.

For example, when the rotation speed of the sun gear 121 is Ns,
Consider a case where the rotation speed of the planetary carrier 123 is Ne and the rotation speed of the ring gear 124 is Nr. Sun gear 121
Is indicated by a point Ps in the alignment chart of FIG. The rotation state of the planetary carrier 123 is indicated by a point Pe, and the rotation state of the ring gear 124 is indicated by a point Pr. The points Ps, Pe, and Pr are respectively located on straight lines called motion collinear lines.

Here, it is assumed that the rotation speed of the ring gear 124, that is, the vehicle speed is reduced while the rotation speed of the planetary carrier 123, that is, the rotation speed of the engine 150 is kept constant. The operating collinear line in such a case is shown by a broken line in FIG. Since the vehicle speed decreases, the rotation state of the ring gear 124 is indicated by a point Pr1 in FIG. The rotation speed of the planetary carrier 123 remains constant at the point Pe. As a result,
The rotation speed of the sun gear 121 increases to a value indicated by the point Ps1.

Each gear of the planetary gear 120 has an upper limit of the number of rotations that can be mechanically permitted. As shown in FIG. 5, if the rotation speed of engine 150 is increased at low speed, the rotation speed of sun gear 121 becomes extremely high, and may exceed the allowable upper limit. To prevent the rotation speed of the sun gear 121 from exceeding the upper limit, for example,
It is necessary to reduce the rotation speed of engine 150 to a value corresponding to point Pe1 in FIG. As described above, in the hybrid vehicle of the present embodiment, the operable range of the engine 150 is limited according to the vehicle speed due to the mechanical limitation of the planetary gear 120. Such a limitation is a speed difference limitation.

FIG. 6 is an explanatory diagram showing the differential speed limitation in the hybrid vehicle of this embodiment. As mentioned above,
The operation is performed at a vehicle speed and an engine speed within a range represented by a usable area in the drawing. In addition, the area shown by the solid line in FIG. 6 shows the usable area when the transmission is directly connected. When the transmission is in the speed increasing state, the number of revolutions input to the planetary gear 120 is higher than the actual number of revolutions of the engine.

(2) General operation: Next, as a general operation of the hybrid vehicle of the present embodiment, an operation of converting the power output from the engine 150 into a required rotation speed and torque and outputting it to the axle 116. Will be described. Hereinafter, the differential gear 11 will be described for ease of explanation.
It is assumed that the gear ratio of 4 has a value of 1. That is,
It is assumed that the rotation speed and torque of the axle 116 and the rotation speed and torque of the drive shaft 112 are equal.

FIG. 7 is an explanatory diagram showing a state of torque conversion in the case of "the rotational speed Nd of the axle 116 <the rotational speed Ne of the engine 150". The horizontal axis represents the rotational speed N and the vertical axis represents the torque T. The operating point Pe of the engine 150 and the axle 1
16 rotation points Pd are shown. A curve P in FIG. 7 is a curve in which the product of the power, that is, the product of the rotation speed and the torque, is constant. It is assumed that power Pe output from engine 150 at rotation speed Ne and torque Te is converted to power Pd having rotation speed Nd lower than Ne and torque Td higher than Te and output from axle 116. Note that the transmission mechanism is in a directly connected state.

When performing the conversion shown in FIG.
Is smaller than the rotation speed Ne of the engine 150. The rotation speed of the planetary carrier 123
The rotation speed Ne is equal to 0, and the rotation speed of the ring gear 124 is equal to the rotation speed Nd of the axle 116. Therefore, as is clear from the above-described equation (1), the rotation speed N of the sun gear 121 is
s and the torque Ts are respectively expressed by the following equation (2). Ns = (1 + ρ1) / ρ1 × Ne−Nd / ρ1; Ts = Te × ρ1 / (1 + ρ1); ρ1 = number of teeth of sun gear 121 / number of teeth of ring gear 124 (2); Since the rotation speed and the torque cannot be individually controlled, the motor 13
0 at the above-mentioned rotation speed and torque,
As a result, the engine 150 is operated at the rotation speed Ne and the torque Te.

The power output from the engine 150 is divided into two by the planetary gear 120, and a part of the power is input to the motor 130 as the power of the rotation speed and the torque. The motor 130 regenerates power equal to the product of the rotation speed Ns and the torque Ts as electric power. According to the above equation (2),
The regenerated power GU1 is expressed by the following equation (3). This power corresponds to the area of the region GU1 in FIG. GU1 = Ns × Ts = Ne × Te−Nd × Te / (1 + ρ1) (3)

The remaining power output from engine 150 is transmitted to ring gear 124 and directly output to axle 116 as mechanical power. According to Expression (1) shown above, the torque Tre output from the engine 150 to the axle 116 is given by “Tre = Te / (1 + ρ1)”. By outputting a torque “Td−Tre”, which is a difference between this torque and the target torque Td of the axle, from the assist motor 140, the rotation speed Nd and the torque Td are applied to the axle 116.
Power can be output. At this time, the assist motor 140 consumes the power of the difference torque × the rotation speed Nd. The consumed power AU1 is represented by the following equation (4).
This power corresponds to the area of the region AU1 in FIG. AU1 = (Td−Te / (1 + ρ1)) × Nd = Td × Nd−Nd × Te / (1 + ρ1) (4)

The assist motor 140 includes a motor 130
The regenerated power is supplied. As is clear from the comparison of the above equations (3) and (4), when the operation is performed at 100% efficiency, the regenerated power GU1 is equal to the consumed power. This is because the second terms of the above equations (3) and (4) are equal, and the first terms are also equal in consideration of Pe and Pd being on the constant power curve P. That is,
"Rotational speed Nd of axle 116 <rotational speed N of engine 150
In the case of "e", torque conversion from the point Pe to the point Pd can be performed by temporarily converting motive power corresponding to the hatched area in FIG. 7 into electric power. Since the operating efficiency does not actually become 100%, the above conversion is realized by taking out the power from the battery 194 or outputting extra power corresponding to the loss from the engine 150. . For the sake of simplicity, the operation of this embodiment will be described below assuming that the operation efficiency is 100%.

FIG. 8 is an explanatory diagram showing a state of torque conversion in the case of "the rotational speed Nd of the axle 116> the rotational speed Ne of the engine 150". When performing the conversion shown in FIG.
The rotation speed Nd of the axle 116 is the rotation speed Ne of the engine 150.
Greater than. Therefore, as is clear from the above equation (2),
The rotation speed Ns of the sun gear 121 becomes negative and reverses. That is, the motor 130 receives power supply and performs power running in the reverse rotation direction. At this time, the consumed power is equal to the absolute value of the above equation (3), and the hatched area AU2 in FIG.
Is equal to the area of

On the other hand, torque Td of axle 116 is smaller than torque Te of engine 150. Therefore, the assist motor 140 is regenerated with a negative torque. The power regenerated at this time is equal to the absolute value of the above equation (4), and is equal to the area of the hatched region GU2 in FIG. Assuming that the operation efficiency of both motors is 100%, the motor 13
The power regenerated at 0 and the power supplied to the assist motor 140 become equal. That is, in the case of “the rotational speed Nd of the axle 116> the rotational speed Ne of the engine 150”, FIG.
By temporarily converting the motive power corresponding to the hatched area into electric power, torque conversion from the point Pe to the point Pd can be performed. In such a conversion, the assist motor 140 located on the downstream side
Since power is supplied to 0, power circulation occurs. FIG.
Region GU3, which is common to both middle regions GU2 and AU2, corresponds to the circulating power.

As described above, the hybrid vehicle of the present embodiment can convert the power output from engine 150 into the power consisting of the required number of revolutions and torque and output it from axle 116 (hereinafter, referred to as the axle 116). This operation mode is referred to as normal running). In addition, the engine 150 can be stopped and the vehicle can travel using the assist motor 140 as a power source (hereinafter, this operation mode is referred to as EV traveling). When the vehicle is stopped, the motor 1
It is also possible to generate electricity by regenerating the 30.

As shown in FIG. 8, the rotation speed N of the axle 116
When the vehicle travels in which d is higher than the rotation speed Ne of the engine 150, power circulation occurs, and the driving efficiency of the vehicle decreases. In the above description, the case where the transmission is in the direct connection state has been described as an example, but power circulation also occurs in the case of the speed increasing connection state. In the above description, the rotation speed Ne of the engine 150 may be replaced with the rotation speed Nc of the planetary carrier 123. Note that power circulation occurs when the sun gear 121 rotates in the reverse direction. According to the equation (2) shown above, the rotation speed of the sun gear 121 is “(1 + ρ1) / ρ1 × Nc−Nd
/ Ρ1 ”, strictly speaking,“ (1 + ρ1)
When the value of “/ ρ1 × Nc” is smaller than the value of “Nd / ρ1”, power circulation occurs. In the following description, a running state that satisfies such conditions and causes power circulation is called overdrive running. The hybrid vehicle according to the present embodiment travels by controlling the transmission mechanism in accordance with the traveling region so as to minimize power circulation and improve driving efficiency.

FIG. 9 is an explanatory diagram showing the use of various running modes in the hybrid vehicle of this embodiment. A curve LIM in the figure indicates an area where the hybrid vehicle can travel. As illustrated, EV traveling is performed in a region where the vehicle speed and the torque are relatively low. In a region where the vehicle speed and the torque are equal to or higher than the predetermined values, the vehicle travels normally. In the area WOD in the figure, the vehicle travels in the speed-up coupled state in principle, and the area UOD
In E, the vehicle runs in a directly connected state. For example, curve D in FIG.
When the traveling state of the vehicle changes along D, after the EV traveling is initially performed, the vehicle shifts to traveling in the speed increasing combined state.

(3) Operation Control Processing: Next, the operation control processing of the hybrid vehicle of this embodiment will be described. As described above, the hybrid vehicle of the present embodiment can travel in various operation modes such as EV traveling and normal traveling. A CPU (hereinafter simply referred to as “CPU”) in the control unit 190 determines an operation mode according to a traveling state of the vehicle, and determines an engine 15 for each mode.
0, motor 130, assist motor 140, clutch 2
10. Control the brake 220. These controls are performed by periodically executing various control processing routines. Hereinafter, the contents of the torque control process in the normal traveling mode among these operation modes will be described.

FIG. 10 is a flowchart of a torque control routine during normal running. When this process starts, CP
U sets the power Pd to be output from the drive shaft 112 (step S10). This power is set based on the accelerator pedal depression amount detected by the accelerator pedal position sensor 165 and the vehicle speed. The power Pd to be output from the drive shaft is represented by the product of the rotational speed Nd * of the drive shaft 112 and the target torque Td *. The rotation speed Nd * is a parameter equivalent to the vehicle speed. The target torque Td * is set in advance as a table according to the accelerator opening and the vehicle speed.

Next, the charge / discharge power Pb and the auxiliary machine driving power Ph are calculated (steps S15 and S20). The charge / discharge power Pb is power required for charging / discharging the battery 194, and takes a positive value when the battery 194 needs to be charged and a negative value when it needs to be discharged. The accessory drive power Ph is electric power required to drive an accessory such as an air conditioner. The sum of the power calculated in this way becomes the required power Pe (step S25).

Next, the CPU sets the operation point of the engine 150 based on the required power Pe thus set (step S30). The operating point is a combination of the target rotation speed Ne of the engine 150 and the target torque Te. The operation points of the engine 150 are basically set with priority given to the operation efficiency of the engine 150 according to a predetermined map.

FIG. 11 is an explanatory diagram showing the relationship between the operating point of the engine and the operating efficiency. The operating state of the engine 150 is shown with the rotational speed Ne on the horizontal axis and the torque Te on the vertical axis. A curve B in the figure indicates a limit range in which the operation of the engine 150 can be performed. Curves α1 to α6 indicate operation points at which the operation efficiency of the engine 150 is constant. The operation efficiency decreases in the order of α1 to α6. In addition, curves C1 to C3 respectively indicate engine 1
4 shows a line where the power (rotational speed × torque) output from 50 is constant.

As shown, the operation efficiency of the engine 150 greatly differs depending on the rotation speed and the torque. When the power corresponding to the curve C1 is output from the engine 150, the operation point (the number of rotations and the torque) corresponding to the point A1 in the drawing has the highest efficiency. Similarly, when the power corresponding to the curves C2 and C3 is output, the highest efficiency is obtained when the operation is performed at points A2 and A3 in the drawing. When an operation point at which the operation efficiency is highest is selected for each power to be output, a curve A in the figure is obtained. This is called an operation curve.

In setting the operating point in step S30 of FIG. 10, the operation curve A experimentally obtained in advance is stored in the ROM in the control unit 190 as a map, and the operation curve corresponding to the required power Pe is obtained from the map. By reading the points, the target rotation speed N of the engine 150 is obtained.
e and the target torque Te are set. By doing so, a highly efficient operating point can be set for engine 150.

The CPU performs a gear ratio switching control process according to the operating point of the engine 150 set in this way (step S100). This process is a process of switching the coupling state of the transmission mechanism between a speed increasing coupling state (the coupling state B in FIG. 2) and a direct coupling state (the coupling state C in FIG. 2) according to the traveling state of the hybrid vehicle. Details of the processing contents will be described later.

Next, the CPU determines whether or not the speed change mechanism is in the speed increasing coupling state (step S200), and in accordance with the coupling state, issues a command of the torque and the rotation speed of the motor 130 and the assist motor 140. A value is set (steps S205, S210). If the vehicle is not in the speed increasing coupling state, that is, if it is in the direct coupling state, the command value is set as follows (step S205). Target rotation speed N1 of motor 130
* Is set by substituting the target rotation speed Nd * of the drive shaft 112 and the engine rotation speed Ne * in the equation (2) shown above. In equation (2), the target torque T1 * of the motor 130 is expressed by the target torque Td * of the drive shaft 112,
Although it can be obtained by substituting the engine target torque Te *, in the present embodiment, the deviation between the target rotation speed N1 * and the actual rotation speed N1 is controlled so that the rotation speed can be accurately controlled to the target value. The target torque T1 * of the motor 130 is set by the proportional integral control based on. Motor 130
The target rotation speed N1 * and the target torque T1 * are set as in the following equation (5). N1 * = (1 + ρ1) / ρ1 × Ne * −Nd * / ρ1; T1 * = K1 × (N1 * −N1) + K2 × Σ (N1 * −N1) (5)

Here, ρ1 is the gear ratio of the planetary gear 120. Also, K in the equation of the target torque T1 *
1 and K2 are gains in the proportional integral control, respectively. K1 is the gain of the proportional term with respect to the deviation of the rotational speed, K2
Corresponds to the gain of the integral term of the rotational speed deviation. These gains can be set in advance by experiments or the like in consideration of control stability and responsiveness. Since the proportional integral control is a well-known technique, further detailed description will be omitted.

The operating point of the assist motor 140 is set as follows. The target rotation speed N2 * of the assist motor 140 is equal to the target rotation speed Nd * of the drive shaft 112. The target torque T2 * is set so as to compensate for a difference between a direct torque transmitted from the engine 150 to the drive shaft 112 via the planetary gear 120 and a target torque Td * of the drive shaft 112. Since the direct torque from the engine 150 varies depending on the torque T1 * of the motor 130, the direct torque is obtained using the torque T1 * set by the above equation (5). By substituting T1 * for the sun gear torque Ts in equation (1) shown above, the direct torque can be obtained as "T1 * / ρ1". As described above, the target rotation speed N2 * and the target torque T2 * of the assist motor 140 are set as in the following equation (6). N2 * = Nd *; T2 * = Td * −T1 * / ρ1 (6)

On the other hand, in the case of the speed increasing coupling state, the command value is set as follows (step S210). Planetary gear 2
Assuming that the gear ratio of 00 is ρ, by the action of the transmission mechanism,
The rotation speed of engine 150 is multiplied by “1 + ρ” and transmitted to planetary gear 120. Therefore, in the above equations (5) and (6), instead of the engine speed Ne *,
By substituting “(1 + ρ) Ne *”, the motor 1
The operation points of 30 and the assist motor 140 are set. Each operating point is set as in the following equation (7). N1 * = (1 + ρ1) / ρ1 × (1 + ρ) Ne * −Nd * / ρ1; T1 * = K1 × (N1 * −N1) + K2 × Σ (N1 * −N1); N2 * = Nd *; T2 * = Td * -T1 * / ρ1 (7)

The CPU controls the operation of the motor 130, the assist motor 140, and the engine 150 based on the torque command value and the rotation speed command value thus set (step S215). As the operation control processing of the motor, a processing known as control of the synchronous motor can be applied. In this embodiment, control by so-called proportional integration control is executed. That is, the current torque of each motor is detected, and the voltage command value to be applied to each phase is set based on the deviation from the target torque and the target rotation speed. The value of the applied voltage is set by the proportional term and the integral term of the deviation. The gain of each term is set to an appropriate value by experiment or the like. The voltage thus set is applied to the drive circuits 191, 1
It is replaced by the switching duty of the transistor inverter constituting 92 and is applied to each motor by so-called PWM control.

The CPU controls the switching of the drive circuits 191 and 192 to thereby control the motor 1 as described above.
30 and the operation of the assist motor 140 are directly controlled. On the other hand, the operation of the engine 150 is actually EF
This is a process performed by the IECU 170. Therefore, the CPU of the control unit 190 outputs the information of the operating point of the engine 150 to the EFIECU 170,
The operation of the engine 150 is indirectly controlled.

By periodically executing the above processing, the hybrid vehicle of this embodiment converts the power output from engine 150 into a desired rotation speed and torque, outputs the power from the drive shaft, and travels. Can be.

Next, the gear ratio switching control processing will be described. FIG. 12 is a flowchart of a gear ratio switching control routine. When this routine is started, the CPU determines the target operating point of the drive shaft 112, that is, the target rotational speed Nd.
* And the target torque Td * (step S10).
2). Next, based on the target operation point of the drive shaft 112, the CPU determines whether the gear ratio needs to be switched (step S104). The determination is made based on which of the area UD and the area OD shown in FIG. The determination of switching will be described with a specific example.

FIG. 13 is an explanatory diagram showing the determination of switching from the direct connection state to the speed increasing connection state. A curve DU shows an example of changes in vehicle speed and torque during running of the hybrid vehicle. When traveling on such a locus, the vehicle is accelerated by outputting a torque larger than the traveling resistance DD. The output torque decreases with acceleration, and eventually the vehicle travels steadily at a speed at which the output torque and the traveling resistance DD are balanced. The switching from the direct connection state to the speed-up connection state occurs, for example, during such an acceleration process. Drive shaft 112 according to the change in vehicle speed
Is changed as indicated by the arrow in the figure, and reaches the boundary point PD1 between the region UD and the region OD, CP
U determines that switching to the speed-up coupled state should be performed.

FIG. 14 is an explanatory diagram showing the determination of switching from the speed increasing coupling state to the direct coupling state. A curve DD is a relationship between the vehicle speed and the torque in a state where the vehicle is traveling on a road with no gradient in a steady state. A state in which the vehicle is running at a certain vehicle speed corresponds to a point PO0 in the drawing. When the driver steps on the accelerator while traveling in this state, the output torque of the vehicle increases as shown by a curve DO in the figure, and the vehicle accelerates. Switching from the speed-up coupling state to the direct connection state occurs, for example, in such a process.
The rotation state of the drive shaft 112 changes according to the arrow in the figure,
When the boundary point PO1 between the area OD and the area UD is reached, C
The PU determines that switching to the direct connection state should be performed.

As described above, the CPU determines the necessity of switching based on whether or not the traveling area of the vehicle shifts between the area UD and the area OD. In the present embodiment, in order to avoid frequent switching of the gear ratio, a certain hysteresis is provided in the switching determination processing. In other words, switching from the direct connection state to the speed-up connection state is performed as shown in FIG.
It is determined that switching is necessary when a predetermined boundary line UL set in the area OD in 3 is reached. When switching from the speed increasing coupling state to the direct coupling state, it is determined that switching is necessary when a predetermined boundary line HL set in the area UD in FIG. 14 is reached. The width of the hysteresis, that is, the curves UL, HL
Can be arbitrarily set in consideration of the driving efficiency of the vehicle, the reduction in ride comfort caused by frequent switching, and the like.

In step S104, if it is determined that switching is necessary, a switching process is executed (step S106). If it is determined that switching is unnecessary, this process is skipped and the gear ratio switching control routine is executed. finish. As shown in FIG. 2, the speed increasing connection state (connection state B) is a connection state in which the clutch 210 is turned off and the brake 220 is turned on. Direct connection state (Connection state C)
Is a coupled state in which the clutch 210 is turned on and the brake 220 is turned off. Switching between the two is performed through a so-called half-clutch state. The switching from the speed increasing connection state to the direct connection state is performed by gradually increasing the oil pressure of the clutch 210 while gradually reducing the oil pressure of the brake 220. Switching from the direct connection state to the speed-up connection state is performed by gradually decreasing the oil pressure of the clutch 210 while gradually increasing the oil pressure of the brake 220. Of course, clutch 210, brake 2
The switching may be performed in such a manner that one of the switches 20 is turned off once (the connection state D in FIG. 2) and then one of the switches 20 is turned on.

According to the hybrid vehicle of the present embodiment described above, the hybrid vehicle can be driven with high efficiency by switching the gear ratio according to the driving state of the vehicle. Hereinafter, such effects will be described.

FIG. 15 is an explanatory diagram showing a state of torque conversion during overdrive traveling. This corresponds to the torque conversion described with reference to FIG. 8, the rotation speed Nd from the drive shaft,
A case where the power of the torque Td is output will be considered. In FIG.
The state of torque conversion when the engine is operated at the point Pe in FIG. 15 is shown. Here, the state of the torque conversion in the speed increasing coupling state is shown. The operating point of engine 150 is the required power and operation curve A (FIG. 11) regardless of the gear ratio.
See)). Therefore, the engine 150 is operated at the point Pe even in the speed-up coupled state. However, in the speed-up coupled state, since the speed is increased by the transmission, the power input to the planetary gear 120 is the power corresponding to the point Pe1 in the figure. That is, the rotational speed Ne of the input power is
1 is higher than the rotation speed Ne of the point Pe, and the torque Te1 is lower than the torque Te of the point Pe.

When such power is input, the hybrid vehicle is driven by the planetary gears 12 in the same manner as shown in FIG.
0, torque conversion is performed by the action of the motor 130 and the assist motor 140. As already described, of the power output from the engine 150, the area GU in FIG.
The power corresponding to the area of 2 'is temporarily replaced by electric power. Further, electric power corresponding to the area of the region AU2 ′ in the drawing is consumed by the motor 130. In such torque conversion, power circulation corresponding to the area of the area GU3 'in FIG. 15 occurs.

Here, FIG. 8 and FIG. 15 are compared. FIG.
Corresponds to the case where torque is converted in the direct connection state, and the area GU3
Circulating power corresponding to the area of FIG. 15 corresponds to the case where the torque is converted in the speed increasing coupling state, and the circulation of the power corresponding to the area of the region GU3 'occurs. As is apparent from the comparison between the two, the area GU3 'has a smaller area than the area GU3. That is, circulating power can be suppressed by performing torque conversion in the speed increasing coupling state.

As described above, the hybrid vehicle of the present embodiment converts the torque and the rotational speed of the power input from the engine 150 to the planetary gear 120 by performing the torque conversion in the speed-up coupled state during the overdrive traveling to drive the drive shaft 11.
2, the target rotation speed Nd and the target torque Td. As a result, the circulating amount of power generated by the torque conversion can be suppressed, and the driving efficiency of the vehicle can be improved.

Note that depending on the gear ratio, it is possible to avoid the occurrence of power circulation. If the gear ratio at the time of increasing the speed is increased, the operating point Pe of the engine 150
The power input to the planetary gear 120 can be increased to the rotation speed corresponding to the point Pe2 in FIG. The rotation speed Nd of the drive shaft 112 is lower than the rotation speed of the point Pe2. Therefore, the torque conversion performed in such a state is performed in the same manner as described with reference to FIG. 7, and no power circulation occurs. By setting such a gear ratio,
The occurrence of power circulation can be avoided even during overdrive traveling, and the hybrid vehicle can be driven with higher efficiency.

The hybrid vehicle according to the present embodiment can switch not only during overdrive but also by switching the gear ratio.
The driving efficiency can be improved even during underdrive traveling. FIG. 16 is an explanatory diagram showing a state of torque conversion during underdrive traveling. This corresponds to the torque conversion described with reference to FIG. Similar to FIG. 7, a case is considered in which power having a rotation speed Nd and a torque Td is output from a drive shaft. FIG. 7 shows a state of the torque conversion when the engine is operated at the point Pe in FIG. Here, a state of torque conversion in a case where the gear ratio is not switched in accordance with the traveling state of the vehicle, that is, in a case where the speed increasing coupling state is maintained even during underdrive traveling, is shown. In the speed-up coupled state, the speed is increased by the transmission, so that the power input to the planetary gear 120 is the power corresponding to the point Pe3 in the figure.

[0100] In response to such power, the hybrid vehicle performs torque conversion by the action of the planetary gear 120, the motor 130, and the assist motor 140, as shown in FIG. As already described, of the power output from engine 150, the power corresponding to the area of region GU1 'in FIG. 16 is temporarily replaced with the electric power. Further, electric power corresponding to the area of the region AU1 ′ in the drawing is consumed by the motor 130.

Here, FIG. 7 and FIG. 16 will be compared. FIG.
Is equivalent to a case where torque is converted in a directly connected state, and the power transmitted once by being replaced with electric power corresponds to the area of the area GU1. FIG. 16 corresponds to the case where the torque is converted in the speed increasing coupling state.
1 '. As is clear from the comparison between the two,
The area GU1 'has a larger area than the area GU1. In other words, the torque transmitted in the speed increasing coupling state during the underdrive traveling increases the power transmitted via the conversion to electric power. Generally, there is a loss in the conversion between electric power and mechanical power. Therefore, if the power transmitted via the conversion to electric power increases, the loss that occurs during torque conversion increases.

In the hybrid vehicle of this embodiment, torque conversion is performed in a directly connected state during underdrive. Therefore, the vehicle can be driven with high efficiency as compared with the case where torque conversion is always performed in the speed increasing state (corresponding to the point Pe3 in FIG. 16). Note that the power of the engine 150 may be reduced and transmitted to the planetary gear 120 during the underdrive traveling. For example, assuming that the power of engine 150 is reduced to a rotation speed corresponding to point Pe4 in FIG. 16 and transmitted to planetary gear 120, the input rotation speed to planetary gear 120 approaches rotation state Pd of drive shaft 112. . As a result, the power once replaced by the electric power during the torque conversion can be further reduced than in the direct connection state, and the operating efficiency can be further improved.

In the hybrid vehicle according to the present embodiment, the direct connection state at the time of the underdrive connection also has an advantage that high power can be easily output as described below. As described above with reference to FIG. 6, in the hybrid vehicle of the present embodiment, there is a speed difference limitation, and the upper limit of the number of revolutions of the engine 150 is determined according to the vehicle speed. Here, it is assumed that the vehicle is traveling at a low speed, for example, traveling at the vehicle speed VL in FIG. In the speed-up coupled state, the upper limit rotational speed of the engine 150 is set to the point P based on the speed difference limit indicated by the broken line in FIG.
The rotation speed is equivalent to L2. In the direct connection state, the upper limit rotation speed of engine 150 is the rotation speed corresponding to point PL1, based on the speed difference limit indicated by the solid line in FIG. As illustrated, the upper limit rotation speed in the direct connection state is higher than the upper limit rotation speed in the speed increasing connection state. Generally, the output of engine 150 increases as the rotational speed increases. Therefore, as a result of the upper limit rotational speed being limited by the above differential speed limitation, a larger power can be output in the direct connection state than in the speed increasing connection state. In the hybrid vehicle of this embodiment, as shown in FIG. 9, the vehicle is driven in a directly connected state in a traveling region where high torque is required. By switching the gear ratio in this manner, power corresponding to the request can be output from engine 150, and the vehicle can be driven with the power consumption of battery 194 suppressed.

By the various operations described above, the hybrid vehicle of the present embodiment can achieve high-efficiency driving by switching the gear ratio according to the running state of the vehicle. In order to realize high-efficiency operation, it is necessary to appropriately set the gear ratio by, for example, the following method.

FIG. 17 is an explanatory diagram showing a method of setting the gear ratio. The horizontal axis shows the input / output rotation speed difference ΔN of the planetary gear 120, and the vertical axis shows the operating efficiency during torque conversion. The rotation speed difference ΔN is “the rotation speed of the planetary carrier 123−the rotation speed of the ring gear 124”.
A positive rotation speed difference ΔN corresponds to the underdrive side, and a negative rotation speed difference ΔN corresponds to the overdrive side. FIG.
As shown by, the power is circulated on the overdrive side, so that the operation efficiency is reduced. As the absolute value of the rotational speed difference ΔN increases, the amount of power circulation increases, and the operating efficiency gradually decreases. Since no power circulation occurs on the underdrive side, the operation efficiency is relatively high. However, as the rotational speed difference increases, the power once transmitted through the replacement with electric power increases, so that the loss during torque conversion increases and the operating efficiency gradually decreases.

The gear ratio is set based on the relationship between the operating efficiency and the rotational speed difference ΔN. First, a target driving efficiency realized by the vehicle is set. Next, a range of the rotational speed difference ΔN that can achieve the target operation efficiency is set. As shown in FIG. 17, if the target operating efficiency is set from the relationship between the rotational speed difference and the operating efficiency, the range of the rotational speed difference ΔN to be realized is ΔN2 to ΔN
It can be set to between three. It goes without saying that this range differs depending on the configuration of the hybrid vehicle.

The gear ratio may be set so that the rotational speed difference ΔN falls within the target range ΔN2 to ΔN3 in the traveling region of the hybrid vehicle. For example, when the hybrid vehicle is running at the maximum vehicle speed and the torque conversion is performed in the directly connected state, the rotation speed difference is represented by ΔN1 in FIG. If a speed ratio at which this rotational speed difference becomes ΔN2 is obtained, a speed ratio on the speed increasing side is set. The gear ratio can be set in the same manner on the underdrive side. The difference in rotation speed realized in the underdrive-side traveling area is ΔN3
If smaller, sufficient operation efficiency can be ensured only in the direct connection state.

The gear ratio is determined by the operating efficiency and the rotational speed difference Δ
It can be set according to the relationship with N. In the embodiment, the case where the speed ratio is switched in two stages, that is, the speed increasing connection state and the direct connection state, has been described. However, the speed ratio is not limited to this, and various settings are possible. It can be set to switch between the deceleration state and the direct connection state, or can be switched in three stages of acceleration, deceleration, and direct connection. Further, the speed may be switched between the speed increasing side and the decelerating side at multiple speed ratios.

In the above-described hybrid vehicle, the case where the transmission gear ratio is switched by the transmission mechanism using the planetary gear 200 has been exemplified. In the embodiment, the planetary gear 200
The clutch 21 connects the brake 220 to the sun gear 201, the engine 150 to the planetary carrier 203, the planetary carrier shaft 206 to the ring gear 204, and further connects the planetary carrier 203 and the ring gear 204.
The case where 0 is provided is exemplified. The connection between the planetary gear 200 and each element is not limited to this, and may take various forms.

FIG. 18 is an explanatory diagram showing a schematic configuration of a hybrid vehicle as a first modified example. Here, only the elements that exchange power are shown. The electrical systems such as the control unit and the drive circuit are not shown. The connection of each element to the planetary gear 200 is different from the configuration of the embodiment (FIG. 1). In the first modified example, the engine 150 is mounted on the sun gear 201, the planetary carrier shaft 206 is mounted on the planetary carrier 203, and the brake 22 is mounted on the ring gear 204.
Join 0. Further, a clutch 210 that couples the planetary carrier 203 and the sun gear 201 is provided. Other configurations are the same as those of the embodiment.

In the hybrid vehicle of the first modified example, by turning off the clutch 210 and turning on the brake 220, the engine 150 can be connected to the planetary gear 120 at a predetermined gear ratio as in the embodiment. According to equation (1) shown above, “Nc = ρ / (1 + ρ) × N
s ”, the realized speed ratio is“ (1
+ Ρ) / ρ ”. Therefore, in the hybrid vehicle of the first modified example, a speed ratio different from that of the hybrid vehicle of the embodiment can be realized without changing the speed ratio of the planetary gear 200. Although illustration is omitted, the connection between the planetary gear 200 and each element is not limited to the example shown in the embodiment and the first modification, and various combinations can be adopted.

In the embodiment and the first modified example, the case where the speed change mechanism using the planetary gear 200 is interposed between the engine 150 and the planetary gear 120 has been exemplified.
The speed change mechanism can be provided downstream of the planetary gear 120. FIG. 19 is an explanatory diagram illustrating a schematic configuration of a hybrid vehicle as a second modification. here,
Only the elements that exchange power are shown. The electrical systems such as the control unit and the drive circuit are not shown. The connection point of the planetary gear 200 is different from the configuration of the embodiment (FIG. 1). That is, in the second modified example, the planetary carrier 20 of the planetary gear 200 constituting the transmission mechanism
3 was connected to the ring gear 124 of the planetary gear 120 constituting the power adjusting device. In addition, planetary gear 2
00 was connected to the drive shaft 112. Other configurations are the same as those of the embodiment.

The hybrid vehicle of the second modification corresponds to a configuration in which the planetary gear 200 is interposed between the power adjusting device and the drive shaft 112. In such a configuration, when the gear ratio is switched, a gear can be shifted between the drive shaft 112 and the ring gear shaft 125 connected to the ring gear 124 of the planetary gear 120 constituting the power adjusting device. In the embodiment, the speed of the input shaft of the planetary gear 120 in the torque conversion is changed by changing the speed.
The difference from the target rotation speed of 2 was reduced, and the operation efficiency was improved. On the other hand, in the second modified example, by changing the speed, the output rotation speed of the planetary gear 120, that is, the target rotation speed of the ring gear shaft 125 is made closer to the target rotation speed of the engine 150, thereby improving the operation efficiency. be able to. Therefore, the same effect as that of the embodiment can be obtained by the second modification.

In the second modification as well, it goes without saying that the state of connection of each element to the planetary gear 200 can take various forms. Further, it is also possible to combine the embodiment and the second modified example and adopt a configuration in which a transmission mechanism is provided on both the upstream side and the downstream side of the planetary gear 120.

Various modifications can be applied to the configuration of the device for performing torque conversion. In the above embodiments and modifications, the sun gear 121 of the planetary gear 120 is
30 and the planetary carrier 123 is connected to the engine 1
The ring gear 124 was connected to the motor 140 and the drive shaft 112. As described above, in such a configuration, power circulation occurs during overdrive traveling. On the other hand, the motor 140 may be connected to the engine 150 side. Such a configuration will be described as a third modification.

FIG. 20 is an explanatory diagram showing a schematic configuration of a hybrid vehicle as a third modification. Here, only the elements that exchange power are shown. The electrical systems such as the control unit and the drive circuit are not shown. The coupling destination of the assist motor 140 is different from the hybrid vehicle of the embodiment. That is, in the hybrid vehicle of the third modified example, the assist motor 140 is connected to the planetary carrier 123 of the planetary gear 120 constituting the power adjusting device. The assist motor 140 is connected to the upstream side of the planetary gear 120.

This configuration corresponds to the connection state described above with reference to FIG. Therefore, as described with reference to FIGS. 26 and 27, the circulation of power occurs during underdrive traveling. Also in the third modified example, operating efficiency can be improved by controlling the gear ratio so that the rotational speed of the power output from engine 150 approaches the target rotational speed of drive shaft 112. In the third modified example, since power circulates during the underdrive traveling, if the speed ratio is set and controlled so that the input / output rotation speed of the planetary gear 120 maintains the relationship corresponding to the overdrive traveling, furthermore, Operation efficiency can be improved. Also in the third modification, various selections can be made for the connection state of each element to the planetary gear 200 constituting the transmission mechanism and the connection position of the planetary gear 200.

In the above embodiments and the like, the planetary gear 12
The case where the torque converter used as the power adjustment device for the motor 0 and the motor 130 is applied is illustrated. The power adjusting device refers to a device capable of adjusting the power input from the engine 150 to power having at least different rotational speeds by exchanging power and transmitting the power. In the embodiment, the planetary gear 1
By powering or regenerating the motor 130 coupled to the motor 20 and controlling the number of rotations, the engine 15
The power output from 0 can be transmitted to the ring gear 124 while changing the magnitude of the power. The power adjustment device
Various other devices can be applied as long as they have such a function. A case where a power adjusting device having a different configuration is applied will be exemplified as a fourth modification.

FIG. 21 is an explanatory diagram showing a schematic configuration of a hybrid vehicle according to a fourth modification. The second modification is different from the embodiment in that a clutch motor 230 is used instead of the planetary gear 120 and the motor 130. Other configurations are the same as those of the hybrid vehicle of the first embodiment (see FIG. 1).

The clutch motor 230 includes the inner rotor 2
32 and an outer rotor 234, both of which are relatively rotatable electric motors. The output shaft of the planetary gear 200 constituting the speed change mechanism, that is, the rotation shaft connected to the ring gear 204, is connected to the inner rotor 232. Outer rotor 234 is connected to drive shaft 112. The drive shaft 112 has an assist motor 1 as in the embodiment.
40 are connected.

The clutch motor 230 is configured as a paired rotor synchronous motor generator, and has an inner rotor 232 having a plurality of permanent magnets on its outer peripheral surface and an outer rotor 234 wound with a three-phase coil forming a rotating magnetic field. And The outer rotor 234 and the inner rotor 232
Both are supported so as to be relatively rotatable. The clutch motor 230 operates as an electric motor in which both are driven to rotate relatively by the interaction between the magnetic field generated by the permanent magnet provided on the inner rotor 232 and the magnetic field formed by the three-phase coil provided on the outer rotor 234. These interactions also operate as a generator that generates electromotive force at both ends of the three-phase coil wound around the outer rotor 234. The exchange of power with the outer rotor 234 is performed via the slip ring 118 and the drive circuit 191.

The clutch motor 230 is connected to the inner rotor 23.
2 and the outer rotor 234 are rotatable,
The power input from one of these can be transmitted to the other. If the clutch motor 230 is driven by power as an electric motor, the number of rotations transmitted to the other shaft can be increased. If the regenerative operation is performed as a generator, it is possible to transmit the power while reducing the number of revolutions while extracting a part of the power in the form of electric power. If neither the power running operation nor the regenerative operation is performed, power is not transmitted. This state corresponds to a state where the mechanical clutch is released. As is clear from the principle of the action / reaction, the torque input to the clutch motor 230 and the output torque are always equal.

A description will be given of torque conversion in the hybrid vehicle having such a configuration. First, "Inner rotor 23
The case where “the rotation speed of 2> the target rotation speed Nd of the drive shaft 112” is considered. In this case, the clutch motor 230 is regeneratively operated, and power is transmitted at a reduced rotation speed so that the rotation speed of the outer rotor 234 becomes the target rotation speed Nd. Since the torque transmitted by the clutch motor 230 is lower than the target torque Td of the drive shaft 112, the torque is added by powering the assist motor 140. The power regenerated by the clutch motor is used for powering the assist motor 140.
In the case of “the rotation speed of the inner rotor 232> the target rotation speed Nd of the drive shaft 112”, electric power is supplied from the clutch motor 230 located on the upstream side to the assist motor 140 located on the downstream side. Does not occur.

Next, first, the case where "the rotational speed of the inner rotor 232 <the target rotational speed Nd of the drive shaft 112" is considered.
In this case, the clutch motor 230 is driven by power, and the power is transmitted by increasing the rotation speed so that the rotation speed of the outer rotor 234 becomes the target rotation speed Nd. Since the torque transmitted by the clutch motor 230 is higher than the target torque Td of the drive shaft 112, the assist motor 140 is regeneratively operated to apply a load. The electric power obtained by the assist motor 140 is used for powering the clutch motor 230. In the case of “the rotation speed of the inner rotor 232 <the target rotation speed Nd of the drive shaft 112”, the assist motor 1 located on the downstream side
Since electric power is supplied from 40 to the clutch motor 230 located on the upstream side, power circulation occurs.

As described above, according to the hybrid vehicle of the fourth modification, similarly to the hybrid vehicle of the embodiment, the power output from engine 150 is torque-converted into power having various rotation speeds and torques. Drive shaft 11
2 can be output. In the process of torque conversion, the point that power transmitted via conversion to electric power exists is the same as in the embodiment. The same applies to the point where power circulation occurs in a predetermined traveling state. Therefore, if the speed ratio is controlled according to the running state so that the difference between the input rotation speed and the output rotation speed of the clutch motor 230 approaches, the operation efficiency of the hybrid vehicle can be improved by the same operation as in the embodiment.

In the fourth modification, as in the modification described in the power adjusting device using the planetary gear 120, various coupling states can be adopted. Further, the power adjusting device is not limited to the configurations of the embodiment and the fourth modified example, and various configurations capable of transmitting power while changing the number of revolutions through exchange of electric power can be applied.

In the embodiments and the like described above, the case where the speed change mechanism using the planetary gear 200 is applied has been exemplified.
Such a speed change mechanism has the advantage of being a relatively simple and small mechanism. However, the present invention is not limited to such a speed change mechanism, and various speed change mechanisms can be applied.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and may be embodied in various other forms without departing from the gist of the present invention. Obviously you can get it.
For example, in the hybrid vehicle of this embodiment, the gasoline engine 150 is used as the engine, but a diesel engine or another device serving as a power source can be used. Further, in the present embodiment, all three-phase synchronous motors are applied as motors, but an induction motor or another AC motor and DC motor may be used. Further, in the present embodiment, various control processes are realized by the CPU executing software, but such control processes may be realized by hardware. Further, the control unit 19
Although the case where the switching control of the gear ratio is performed by 0 has been described as an embodiment, it is also possible to configure in a mode in which switching is performed manually, or in a mode in which automatic switching and manual switching can be selected.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a schematic configuration of a hybrid vehicle according to an embodiment.

FIG. 2 is an explanatory diagram showing an operation of a transmission mechanism.

FIG. 3 is an explanatory diagram schematically showing a coupling state equivalent to a case where a clutch 210 is turned off and a brake 220 is turned on.

FIG. 4 is an explanatory diagram schematically showing a coupling state equivalent to a case where a clutch 210 is turned on and a brake 220 is turned off.

FIG. 5 is an explanatory diagram showing a rotation state of the planetary gear 120.

FIG. 6 is an explanatory diagram showing a differential speed limit in the hybrid vehicle of the embodiment.

FIG. 7 is an explanatory diagram illustrating a state of torque conversion in a case where “the rotational speed Nd of the axle 116 <the rotational speed Ne of the engine 150”.

FIG. 8 is an explanatory diagram illustrating a state of torque conversion in a case where “the rotational speed Nd of the axle 116> the rotational speed Ne of the engine 150”.

FIG. 9 is an explanatory diagram showing how to use various traveling modes in the hybrid vehicle of the embodiment.

FIG. 10 is a flowchart of a torque control routine during normal running.

FIG. 11 is an explanatory diagram showing a relationship between an operating point of an engine and an operating efficiency.

FIG. 12 is a flowchart of a gear ratio switching control routine.

FIG. 13 is an explanatory diagram showing a determination of switching from the direct connection state to the speed increasing connection state.

FIG. 14 is an explanatory diagram showing a determination of switching from a speed increasing coupling state to a direct coupling state.

FIG. 15 is an explanatory diagram showing a state of torque conversion during overdrive traveling.

FIG. 16 is an explanatory diagram showing a state of torque conversion during underdrive traveling.

FIG. 17 is an explanatory diagram showing a method of setting a gear ratio.

FIG. 18 is an explanatory diagram showing a schematic configuration of a hybrid vehicle as a first modified example.

FIG. 19 is an explanatory diagram showing a schematic configuration of a hybrid vehicle as a second modified example.

FIG. 20 is an explanatory diagram showing a schematic configuration of a hybrid vehicle as a third modified example.

FIG. 21 is an explanatory diagram illustrating a schematic configuration of a hybrid vehicle according to a fourth modified example.

FIG. 22 is an explanatory diagram showing a schematic configuration of a hybrid vehicle in which an electric motor is coupled to a drive shaft.

FIG. 23 is an explanatory diagram showing how power is transmitted in a hybrid vehicle in which an electric motor is coupled to a drive shaft in a state where the engine speed is higher than the drive shaft speed.

FIG. 24 is an explanatory diagram showing how power is transmitted in a hybrid vehicle in which an electric motor is coupled to a drive shaft in a state where the engine speed is lower than the drive shaft speed.

FIG. 25 is an explanatory diagram illustrating a schematic configuration of a hybrid vehicle in which an electric motor is coupled to an output shaft.

FIG. 26 is an explanatory diagram showing a state of transmission of power in a hybrid vehicle in which an electric motor is coupled to an output shaft in a state where the engine speed is higher than the drive shaft speed.

FIG. 27 is an explanatory diagram showing a state of power transmission in a state where the rotation speed of the engine is lower than the rotation speed of the drive shaft in the overdrive coupling.

[Explanation of symbols]

 112 ... drive shaft 114 ... differential gear 116R, 116L ... drive wheel 116 ... axle 117 ... rotation speed sensor 118 ... slip ring 120 ... planetary gear 121 ... sun gear 122 ... planetary pinion gear 123 ... planetary carrier 124 ... ring gear 125 ... ring gear shaft 130 ... motor 132 ... rotor 133 ... stator 140 ... assist motor 142 ... rotor 143 ... stator 150 ... engine 152 ... rotation speed sensor 156 ... crankshaft 165 ... accelerator pedal position sensor 190 ... control unit 191, 192 ... drive circuit 194 ... battery 200 ... planetary gear 201 sun gear 202 planetary pinion gear 203 planetary carrier 204 ring gear 205 ring gear shaft 21 0: clutch 220: brake 230: clutch motor 232: inner rotor 234: outer rotor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B60L 15/20 H02P 15/00 D H02K 7/10 B60K 9/00 Z H02P 15/00 F term (Reference) 3D039 AA04 AB26 AC39 3J052 AA11 AA14 GC43 GC44 HA02 LA01 5H115 PA01 PG04 PI16 PI24 PI29 PI30 PU10 PU22 PU24 PU25 PV09 PV23 QA01 QN03 RB08 RB22 RE05 SE04 SE05 SE08 SJ12 TB01 TO21 5H607 BB01 BB02 EE07 CCB CC HH03

Claims (11)

[Claims] An engine having an output shaft, a drive shaft for outputting power, a first rotation shaft connected to the output shaft side, and a second rotation shaft connected to the drive shaft side. A hybrid vehicle comprising: a torque conversion unit that converts a rotation speed and a torque of the first rotation shaft through conversion between power and electric power, and that can output the converted rotation speed and torque to the second rotation shaft. A hybrid vehicle including a transmission that is interposed in a path until power output from an engine is output to the drive shaft and transmits power at a predetermined gear ratio. 2. The hybrid vehicle according to claim 1, wherein target power setting means for setting a target power of the drive shaft by a combination of a target rotation speed and a target torque; An engine control means for operating the engine at a rotational speed and a torque set with priority; controlling the transmission to input an rotational speed of the first rotational shaft and an output rotational speed of the second rotational shaft; And a transmission control means for realizing a gear ratio in which the difference is within a predetermined range set in advance. 3. The hybrid vehicle according to claim 2, wherein the transmission has a magnitude relationship between the input rotation speed and the output rotation speed in a traveling region of the hybrid vehicle.
At least a mechanism that transmits power at a speed ratio set within a range that can maintain a high conversion efficiency by the torque conversion unit, wherein the transmission control unit controls the transmission, and A hybrid vehicle, which is means for maintaining a magnitude relationship between an input rotation speed and an output rotation speed on the higher conversion efficiency side. 4. The hybrid vehicle according to claim 3, wherein the torque conversion means is coupled to the first rotation shaft and the second rotation shaft, and the first rotation shaft is connected to the first rotation shaft by exchange of electric power. A power adjusting device that adjusts power to at least power having a different rotation speed and transmits the power to the second rotating shaft; and a motor coupled to the second rotating shaft, wherein the conversion efficiency is higher. Is a hybrid vehicle in which the input rotation speed is higher than the output rotation speed. 5. The hybrid vehicle according to claim 3, wherein the torque conversion unit is coupled to the first rotation shaft and the second rotation shaft, and the first and second rotation shafts are connected by power exchange. A power adjusting device that adjusts power to at least power having a different rotation speed and transmits the power to a second rotating shaft; and a motor coupled to the first rotating shaft, wherein the conversion efficiency is higher. The relationship is that the input rotation speed is smaller than the output rotation speed. 6. The hybrid vehicle according to claim 1, wherein said transmission is provided between said output shaft and torque conversion means. 7. The hybrid vehicle according to claim 1, wherein said transmission is provided between said torque conversion means and said drive shaft. 8. The hybrid vehicle according to claim 1, wherein the transmission comprises: a planetary gear in which two of the three rotation shafts are respectively coupled to the output shaft side and the drive shaft side; A hybrid vehicle, comprising: a stopping means capable of selectively rotating and stopping the remaining rotating shaft of the planetary gear; and a connecting means capable of selectively connecting and releasing the two rotating shafts. 9. The hybrid vehicle according to claim 1, wherein the torque conversion unit includes: a generator having a rotor shaft; and three rotation shafts, wherein the rotation shaft is the output shaft, the drive shaft,
And a planetary gear coupled to the rotor shaft, and a motor coupled to one of the first rotation shaft and the second rotation shaft. 10. The hybrid vehicle according to claim 1, wherein said torque conversion means comprises: a first rotor coupled to said first rotation shaft; and a second rotor coupled to said second rotation shaft. And an electric motor coupled to one of the first rotating shaft and the second rotating shaft. 11. An engine having an output shaft, a drive shaft for outputting power, and a first shaft coupled to the output shaft.
And a second rotating shaft coupled to the drive shaft side, the rotational speed and the torque of the first rotating shaft being converted through the conversion between power and electric power, and the second rotation A hybrid vehicle comprising: a torque conversion unit capable of outputting power to a shaft; and a transmission interposed in a path until power output from the engine is output to the drive shaft and transmitting power at a predetermined gear ratio. A control method for controlling operation, comprising: (a) setting a target power of the drive shaft by a combination of a target rotation speed and a target torque; and (b) responding to the target power.
(C) operating the engine at a rotational speed and a torque set with priority given to operating efficiency; and (c) calculating a difference between an input rotational speed of the first rotational shaft and an output rotational speed of the second rotational shaft.
Controlling the speed ratio of the transmission to fall within a predetermined range set in advance.