JPH11299007A - Power output device, its control method and hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the operation efficiency of a hybrid power output device with two output shafts. SOLUTION: A part of the output power of an engine 150 is transmitted to front wheels 116 via a clutch motor CM and the remaining power is regenerated as an electric power. A motor linked with rear wheels 118 is driven by using the electric power. In a hybrid vehicle which has the fundamental construction as described and enables four-wheel drive, a DC motor is provided between the engine 150 and the clutch motor CM as a generator G. In an overdriven state, an electric power is regenerated by the generator G to suppress the power transmitted to the front wheels 116, so as to prevent the power exceeding the requested power from being outputted from the front wheels 116. With this constitution, since it is not necessary to regenerate a power from the rear wheels 118, the circulation of the power is eliminated and an operation efficiency is improved. Furthermore, as the DC motor is employed, the improvement can be realized with a very simple construction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid power output device having a prime mover and an electric motor as power sources and a hybrid vehicle equipped with the power output device, and more particularly to a power output device having two output shafts and The present invention relates to a four-wheel drive hybrid vehicle equipped with the device.

[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. In a parallel hybrid vehicle, power output from an engine is distributed by a power distribution device. Part of the distributed power is transmitted to the output shaft, and the rest is converted to electric power by the generator. This power is stored in a battery or used to drive a motor coupled to the output shaft. With this configuration, the parallel hybrid vehicle can output the power output from the engine to the output shaft at an arbitrary rotation speed and torque. Since the engine can be operated by selecting a driving point with high driving efficiency, the hybrid vehicle is more excellent in resource saving and exhaust purification than the conventional vehicle using only the engine as a driving source.

[0003] On the other hand, a hybrid vehicle that can be driven by four wheels using the above-described parallel hybrid vehicle technology has also been proposed (for example, the technology described in JP-A-9-175203). FIG. 10 shows a configuration example of a hybrid vehicle capable of driving four wheels. In such a hybrid vehicle, the motor 50
The inner rotor 34 of the clutch motor 30 is connected to the output shaft of the
2 is connected to the drive shaft 22. The drive shaft 22 includes a transmission gear 23
And a front wheel 26 via a differential gear 24,
28. An electric motor 40 is provided on the rear wheels 27 and 29.
And the electric motor 40 is connected to a battery 94 via a drive circuit 92. Clutch motor 30
Is also electrically connected to the battery 94 via the drive circuit 91. Accordingly, the electric motor 40 and the clutch motor 30 are electrically connected via the battery 94.

The clutch motor 30 exchanges electric power in accordance with the relative slip between the inner rotor 34 and the outer rotor 32, and transmits and outputs the power output from the prime mover 50 to the drive shaft 22 while increasing or decreasing the power. It plays a role. In the case of “the rotation speed of the prime mover 50> the rotation speed of the drive shaft 22”, that is, in the underdrive state, the direction in which the outer rotor 34 of the clutch motor 30 rotates relative to the inner rotor 32 is determined by the rotation direction of the inner rotor 32. And the opposite direction. At this time, the clutch motor 30 is regenerated. Therefore, the prime mover 5
A part of the power output from 0 is transmitted to the drive shaft 22 by the operation of the clutch motor 30 to drive the front wheels 26 and 28, and the remaining power is converted into electric power. This electric power is used for driving the rear wheels 27 and 29 by the electric motor 40.

Conversely, when "the rotational speed of the prime mover 50 <the rotational speed of the drive shaft 22", that is, in the overdrive state, the direction in which the outer rotor 34 of the clutch motor 30 rotates relative to the inner rotor 32. Is in the same direction as the rotation direction of the inner rotor 32. At this time, the clutch motor 30 is driven by power. Therefore, the sum of the power output from the prime mover 50 and the power generated by the clutch motor 30 is transmitted to the drive shaft 22 to drive the front wheels 26 and 28.
Since the prime mover outputs power equal to the power to be output from the front and rear wheels, the clutch motor 3 is output from the front wheels 26 and 28.
Excessive power is output by the power output from zero. Accordingly, in the overdrive state, electric power is regenerated by the electric motor 40 coupled to the rear wheels 27 and 29, and a load torque is applied to the rear wheels so that the power output from the front and rear wheels matches the required power. By the operation described above, the hybrid vehicle shown in FIG.
Traveling by four-wheel drive is possible in various driving states.

In order to realize four-wheel drive in a conventional vehicle using only an engine as a power source, a propeller shaft has been used to transmit the power of the engine to both front and rear wheels. This has many disadvantages in terms of weight and the effect on the interior space of the vehicle. The above-described hybrid vehicle has a great advantage in that four-wheel drive can be realized without using a propeller shaft. A four-wheel drive hybrid vehicle is also excellent in that the characteristics of the hybrid vehicle, which are excellent in resource saving and exhaust purification, can be utilized in a four-wheel drive vehicle.

[0007]

However, in a hybrid vehicle capable of four-wheel drive, the driving efficiency may be reduced when the vehicle runs in an overdrive state. As described above, at the time of overdrive, the clutch motor 30 performs the power running operation, and the electric motor 40 performs the regenerative operation. The electric power regenerated by the electric motor 40 is used for the power running operation of the clutch motor 30. That is, in the overdrive state, the engine 5
A part of the power output from 0 is output from the front wheels 26 and 28 once, then regenerated by the electric motor 40, and is again supplied to the drive of the clutch motor 30 so that the front wheels 26 and 2 are driven again.
8 is formed. Since the operating efficiency of each device such as the electric motor 40 is not necessarily 100%, when the above-described circulation is formed, the power that is lost as heat among the power output from the engine 50 increases. In a conventional hybrid vehicle, the driving efficiency may decrease during overdrive due to such a cause.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to improve the operating efficiency of a hybrid power output device having two output shafts. It is another object of the present invention to provide a four-wheel drive hybrid vehicle in which such a power output device is applied to a vehicle.

[0009]

Means for Solving the Problems and Their Functions / Effects In order to solve at least a part of the above problems, the present invention has the following constitution. The power transmission device of the present invention has a first output shaft, a second output shaft, and a prime mover, and can output power output from the prime mover from the first output shaft and the second output shaft. A power output device that is coupled to an output shaft of the prime mover and the first output shaft, and that increases / decreases power output from the prime mover by exchanging power and transmits power to the first output shaft. Means, said second
An electric motor coupled to the output shaft of the first output shaft and capable of inputting and outputting power to and from the second output shaft, and controlling the operation of the prime mover, the power transmission means and the electric motor to output the power output from the first output shaft and Power control means for making the sum of the power output from the second output shaft equal to the required power, and a power transmission in which the power output from the prime mover is transmitted to the first output shaft A generator provided in the path, a drive circuit for generating electric power by the generator, a detecting unit for detecting a rotational speed of the motor, and a detecting unit for detecting a rotational speed of the first output shaft, By controlling the drive circuit of the generator, when the rotational speed of the prime mover is smaller than the rotational speed of the first output shaft, by regenerating a part of the power output from the prime mover as electric power, Apply a predetermined load to the power transmission path And summarized in that and a power generation control unit to obtain.

In the above power transmission device, when the power output from the prime mover is transmitted to the first output shaft through the power transmission path, "the rotational speed of the prime mover <the rotational speed of the first output shaft", that is, the overdrive When in the state, a predetermined load is applied by the generator. In the overdrive state, if there is no load from the generator, excessive power exceeding the required power is output from the first output shaft, so it is necessary to regenerate excessive power from the second output shaft. This resulted in power circulation. On the other hand, in the power output device of the present invention, the power output from the prime mover is reduced by the load applied to the power transmission path by the generator and transmitted to the first output shaft. That is, excessive power output from the first output shaft can be suppressed. Therefore, according to the power output device of the present invention, the above-described power circulation can be suppressed, and the operating efficiency can be improved.

In addition, the power output apparatus of the present invention has an advantage that the operation efficiency can be improved by the above-described effect with a very simple configuration. In the present invention, a generator is provided in the power transmission path. This does not function as a motor driven by receiving power supply at least while the prime mover is operating. Therefore, the configuration of the drive circuit for controlling the operation of the generator becomes very simple. Further, the size of the generator itself can be suppressed. As a result, the operating efficiency can be improved without extremely increasing the size, weight, manufacturing cost, and the like of the device as compared with the conventional power output device.

Here, in the above invention, the control is performed in accordance with the magnitude relationship between the rotation speed of the prime mover and the rotation speed of the first output shaft. The rotation speed of the first output shaft means a rotation speed immediately after the power transmission means. In other words, when a speed reduction gear or the like is interposed between the first output shaft rotation speed detection means and the power transmission means, the magnitude relationship is determined in consideration of the speed reduction ratio of the speed reduction gear. Will be.

[0013] When the operation of the prime mover is stopped, the generator may function as a motor driven by receiving supply of electric power. For example, it may be possible to function as a starter for starting a prime mover. Even in such a case, since the drive circuit of the generator can be realized with a very simple configuration, the above-described effects can be obtained.

In the above power transmission device, the generator is a generator capable of changing a power generation load, and the predetermined load is coupled to a second output shaft as a result of control by the power control means. It is desirable that the load is such that the output torque of the motor can be set to a value of 0 or more.

According to such a power output device, the output torque of the electric motor coupled to the second output shaft can be made 0 or more, so that the circulation of power can be eliminated and the operation efficiency can be greatly improved. Can be.

In the power output device, various generators can be applied, but it is preferable that the generator is a DC generator. In this way, the drive circuit of the generator can be made very simple.

The power transmission means in the above-described power output device can have various configurations. For example, the power transmission means may include a first rotor coupled to an output shaft of the prime mover, and a second rotor coupled to the first output shaft and rotatable relative to the first rotor. Power is transmitted and received through electromagnetic coupling and relative slippage between the first rotor and the second rotor to increase or decrease the power output from the prime mover,
Means for transmitting to the output shaft.

Further, the power transmission means is provided separately from the generator, and is coupled to a motor generator having an input shaft, an output shaft of the prime mover, the first output shaft, and the input shaft, respectively. Power input / output means having three axes, and determining power input / output to / from two axes of the three axes; and determining power input / output to / from the remaining one axis. it can.

In the former, the power output from the prime mover can be increased or decreased by exchanging power through relative slippage between the first rotor and the second rotor. Further, the power output from the prime mover can be transmitted to the first output shaft via an electromagnetic coupling between the two.
In the latter, by controlling the operating state of the motor generator coupled to the input shaft, the power transmitted to the first output shaft can be transmitted while increasing or decreasing.

The power output device described above can be used for various devices that require two output shafts. Such a device includes, for example, a vehicle that can be driven by four wheels. Therefore, the present invention can be configured as the following hybrid vehicle. The hybrid vehicle of the present invention can output power from the prime mover using at least a prime mover and an electric motor from the front axle and the rear axle, using a front axle coupled to the front wheels and a rear axle coupled to the rear wheels. A four-wheel drive hybrid vehicle having a power output device, wherein the power output device is coupled to an output shaft and the front axle of the prime mover to increase or decrease the power output from the prime mover by exchanging power. Power transmission means capable of transmitting power to the front axle, an electric motor coupled to the rear axle, capable of inputting and outputting power to the rear axle, controlling the operation of the prime mover, the power transmission means and the electric motor, Power control means for making the sum of the power output from the front axle and the power output from the rear axle equal to the required power, further comprising: A generator provided in the power transmission path in which the power is transmitted to the front axle, a driving circuit for performing power generation by the generator,
Detecting means for detecting the rotational speed of the prime mover, detecting means for detecting the rotational speed of the front axle, and controlling the drive circuit of the generator so that the rotational speed of the prime mover is greater than the rotational speed of the front axle A gist of the invention is a power output device including: a power generation control unit that regenerates a part of the power output from the prime mover as electric power to apply a predetermined load to the power transmission path when the power is small.

According to the hybrid vehicle, similarly to the above-described power output device, the circulation of power in the overdrive state can be suppressed, and the driving efficiency can be improved. Further, in the above-described hybrid vehicle, the driving efficiency can be improved without extremely increasing the size, weight, and cost of the power output device itself.
In a vehicle, the space and weight for mounting the power output device usually have very severe restrictions, so the above-mentioned effects according to the present invention are particularly significant.

Also in the invention of the hybrid vehicle, the generator is a generator capable of changing a power generation load,
It is preferable that the predetermined load is a load capable of setting an output torque of a motor coupled to a rear axle to a value of 0 or more as a result of the control by the power control unit. Also,
Preferably, the generator is a DC motor. In this case, the effect of improving the operation efficiency and the effect of suppressing the size of the device can be obtained to the maximum.

On the other hand, the present invention can be regarded as a control method for controlling the operation of the power output device. The method for controlling a power output device according to the present invention includes a first output shaft and a second output shaft, a prime mover, and the power output device are coupled to the output shaft and the first output shaft of the prime mover. Power transmission means capable of increasing and decreasing the output power and transmitting the power to the first output shaft; an electric motor coupled to the second output shaft and capable of inputting and outputting power to and from the second output shaft; And a generator provided in a power transmission path through which power output from the motor is transmitted to the first output shaft. The power output from the prime mover is supplied to the first output shaft and the second output shaft.
A control method for controlling the operation of the power output device capable of outputting from the output shaft of (a), wherein (a) detecting the rotation speed of the prime mover; and (b) detecting the rotation speed of the first output shaft. And (c) regenerating a part of the power output from the prime mover by the generator as electric power when the rotational speed of the prime mover is lower than the rotational speed of the first output shaft. (D) applying a predetermined load to the transmission path; and (d) a load by the generator so that the sum of the power output from the first output shaft and the second output shaft matches the required power. Controlling the operation of the prime mover, the power transmission means, and the electric motor in accordance with the above.

If the power output device is controlled by such a control method, the circulation of power can be suppressed, and the operating efficiency can be improved. Although the above control method is directed to a power output device having a generator in a power transmission path, it is sufficient that a device capable of functioning as a generator is provided here. In other words, the control method according to the present invention can be applied to a motor that can function as a motor during the operation of a prime mover as long as a load generated by power generation can be applied to a power transmission path during overdrive. .

In the control method, the step (c)
(C-1) a step of obtaining, as a load by the generator, a load in which the output torque of the motor is assumed to be equal to or greater than 0 in the step (d); It is desirable to include a step of regenerating electric power.

In this way, the circulation of power can be eliminated, and the operating efficiency of the power output device can be greatly improved.

[0027]

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 a four-wheel drive hybrid vehicle equipped with the power output device of the present embodiment.

A power output device mounted on the hybrid vehicle transmits power output from an engine 150 as a prime mover to a front axle 116 corresponding to a first output shaft and outputs the power from front wheels 116R and 116L. The system includes a system, a rear wheel power system transmitting to a rear axle 118 corresponding to a second output shaft and outputting from rear wheels 118R and 118L, and a control system for controlling these operations.

The control system includes a control unit (ECU) 190 for controlling the operation of the entire power output device and the engine 1
It is composed of an EFIECU 170 that controls 50 operations. The ECU 190 and the EFIECU 170 are one-chip microcomputers each having a CPU, a ROM, a RAM, and the like inside. Each CPU is RO
In accordance with the program recorded in M, various control processes described later are performed. To enable these controls, the ECU 1
Various sensors and switches are electrically connected to 90 and EFIECU 170. The sensors connected to the ECU 190 include an accelerator pedal position sensor, a battery capacity sensor, and the like. However, illustration of these sensors is omitted. The ECU 190 directly controls the operation of various electric motors provided in the power output device, and indirectly controls the operation of the engine 150 by transmitting various information to the EFIECU 170.

The configuration of the front wheel power system will be described. Engine 150 as a power source is a gasoline engine used in a normal vehicle. A crankshaft 156, which is an output shaft of the engine 150, is connected via a damper 130 to a clutch motor C acting as power transmission means.
M is mechanically coupled to the inner rotor shaft 133.
The damper 130 connects the crankshaft 156 of the engine 150 to the inner rotor shaft 133 and is provided for the purpose of suppressing the amplitude of the torsional vibration of the crankshaft 156. The inner rotor shaft 133 is a rotation shaft of the inner rotor 132 of the clutch motor CM. The clutch motor CM is an anti-rotor motor having an inner rotor 132 and an outer rotor 134, both of which can be relatively rotated as described later. An outer rotor 134 of the clutch motor CM is connected to a front axle 116 having front wheels 116R and 116L via an outer rotor shaft 135, a power transmission gear 111, and a differential gear 114. On the other hand, a generator G is connected to the crankshaft 156 via a reduction gear 113.

The clutch motor CM is configured as a synchronous motor generator having a pair of rotors, and has an inner rotor 132 having a plurality of permanent magnets on its outer peripheral surface and U, U, which form a rotating magnetic field.
And an outer rotor 134 wound with a three-phase coil having three phases of V and W. Both are rotatably supported on each other. Clutch motor CM is slip ring 128
And a drive circuit 191 to electrically connect to the battery 194.

FIG. 2 shows the configuration of the driving circuit 191. The drive circuit 191 is configured as a transistor inverter as shown in FIG. Source-side transistor (Fig. 2
Tu +, Tv +, Tw +) and sink-side transistors (Tu-, Tv-, Tw- in FIG. 2) are provided as a set of two for each of U, V, and W phases of the clutch motor CM. ing. The source side is connected to the positive side of the battery 194, and the sink side is connected to the negative side of the battery 194. Each transistor has a diode called a flywheel diode (Du +,
Du−, Dv +, Dv−, Dw +, Dw−) are connected in parallel.

The drive circuit 191 is electrically connected to the ECU 190. Drive circuit 191 from ECU 190
Output signals Gu, Gv, Gw for controlling the switching of the U, V, W phase transistors. As shown in FIG. 1, for example, the signal Gu is branched into two, and is input as a gate signal to the transistors Tu + and Tu- via delay circuits Dly + and Dly- and AND gates Ag + and Ag-, respectively. Since the signal transmitted to the sink-side transistor Tu- is inverted by the inverter Inv on the way, when a high or low signal is input as the signal Gu, the transistors Tu + and Tu- are alternately turned on / off. The same configuration applies to the V phase and the W phase.

When the switching of the drive circuit 191 is controlled, the battery 194 is connected to the three-phase coil of the clutch motor CM.
Current flows from the inner rotor 132 and the outer rotor 1
34 operates as an electric motor driven to rotate relatively. This state is called power running operation. Further, when the switching of the drive circuit 191 is controlled so that the three-phase coil can be energized, and an external force is applied to the inner rotor 132 and the outer rotor 134 to rotate them relatively, both ends of the three-phase coil are generated. It operates as a generator to generate power. This state is called regenerative operation.

Note that a shutdown signal SD for turning off all the transistors is also output from the ECU 190 to the drive circuit 191. When a low signal is output as a shutdown signal from the ECU 190, all outputs through the AND gates become low, so that all transistors can be turned off. At this time, the clutch motor CM
Is in a state of neither power running nor regeneration.

The clutch motor CM is an inner rotor 132
Since both the outer rotor 134 and the outer rotor 134 are rotatable, the power input from the inner rotor shaft 133 can be transmitted to the outer rotor shaft 135. Clutch motor CM
When the power running operation is performed, power to which torque is added is transmitted to the outer rotor shaft 135. When the regenerative operation is performed, the remaining power can be transmitted while taking out part of the power in the form of electric power. When neither the power running operation nor the regenerative operation is performed, power is not transmitted from the inner rotor 132 to the outer rotor 134. This state corresponds to a state where the clutch is released.

The generator G is different from the clutch motor CM and is configured as a DC motor. That is, the stator 148 is provided with a winding that generates a uniform magnetic field that does not rotate when energized, and the rotor 146 includes a winding that can be energized via a brush. The generator G is connected to the battery 194 via the drive circuit 193. FIG. 3 shows the configuration of the driving circuit 193. The drive circuit 193 includes a transistor T connected between the plus side of the battery 194 and the generator G, and a diode D connected in parallel to the transistor. Transistor T
Is electrically connected to the ECU 190. ECU1
From 90, a gate signal for controlling ON / OFF of the transistor T is output to the drive circuit 193. When the transistor T is turned on by a gate signal from the ECU 190, the power of the battery 194 causes the generator G to rotate as a motor. When the generator G is rotated by an external force after the transistor is turned off, the power generated there can be charged in the battery 194. At this time, by controlling the duty at which the transistor T is turned on, it is possible to control the power generation load and the like of the generator G.

Another configuration example of the drive circuit 193 is the drive circuit 1
This is shown in FIG. 4 as 93a. Such a configuration may be adopted instead of the configuration in FIG. In the embodiment shown in FIG. 4, the drive circuit 193 includes a thyristor S connected to the plus side of the battery 194 and the generator G. The thyristor S is electrically connected to the ECU 190.
A gate signal for controlling ON / OFF of thyristor S is output from ECU 190. When the generator G is rotated by an external force after the thyristor S is turned on, the battery 194 can be charged with the generated power. When the thyristor S is off, no current flows through the generator G. That is, when the configuration in FIG. 4 is employed, the generator G cannot be rotated as a motor. Further, the power generation load by the generator G cannot be controlled. The illustration of a turn-off circuit for turning off the thyristor S is omitted.

In this embodiment, the generator G is used in order to take advantage of the fact that the drive circuit can be simplified.
Although a DC motor is used as an example, an AC motor can be applied as a matter of course. When an AC motor is employed, it is desirable to apply the inverter shown in FIG. 2 as the drive circuit.

Next, the rear wheel power system will be described. As shown in FIG. 1, an assist motor AM is provided in the rear wheel power system. The output shaft of the assist motor AM coupled to the rotor 142 is provided with rear wheels 118R and 118L via a differential gear 115. It is connected to the axle 118. The stator 144 of the assist motor AM is fixed to the case.

The assist motor AM is also a clutch motor C
Like M, it is configured as a synchronous motor generator, and includes a rotor 142 having a plurality of permanent magnets on the outer peripheral surface, and a stator 143 around which a three-phase coil forming a rotating magnetic field is wound. The assist motor AM is electrically connected to a battery 194 via a drive circuit 192. Drive circuit 192
Is the same as that of the drive circuit 191 (see FIG. 2). The drive circuit 192 is electrically connected to the ECU 190. Therefore, by outputting a signal for controlling the switching of the drive circuit 192 from the ECU 190, the assist motor AM can be powered or regenerated.

(2) Torque control processing: Next, the torque control processing of the hybrid vehicle of this embodiment will be described.
The hybrid vehicle having the above-described configuration outputs power corresponding to the required power from the engine 150 during normal running, and converts the output power into a desired rotation speed and torque while the front axle 116 and the rear axle 118 And transmitted to both axes. FIG. 5 shows the control for outputting the required power from the front axle 116 and the rear axle 118.
It will be described using FIG. FIG. 5 is a flowchart showing the flow of the torque control routine of the power output device of the present embodiment. This routine is periodically executed by the CPU provided inside the ECU 190 described above.

When the torque control routine is started, the CPU
Calculates the drive shaft output energy Pd as the sum of the power output from the front axle 116 and the rear axle 118 (step S10). This energy Pd corresponds to the energy required for running the hybrid vehicle. The drive shaft output energy Pd is calculated according to the vehicle speed of the hybrid vehicle, the amount of accelerator depression detected by an accelerator pedal position sensor, and the like.

Since the torque control is performed in consideration of the energy balance per unit time, the term “energy” in the following description means all the energy per unit time. Therefore, in this specification, the term energy is synonymous with power. Similarly, electric energy is synonymous with electric power.

Next, the CPU calculates the charge / discharge power Pb (step S15). The state of charge of the battery 194 is controlled to be maintained within a predetermined range.
The charging / discharging power Pb is energy required for charging and discharging to maintain the state of charge of the battery 194 in such a range. Subsequently, the CPU calculates the driving energy Ph of the accessory (Step S20). The accessory means an electric device such as an air conditioner mounted on the vehicle.

The required power Pe is calculated from the sum of the energies calculated above (step S25). That is,
Pe = Pr + Pb + Ph. This power is engine 1
This is the power to be output from 50. The operating point of the engine 150, that is, the target rotation speed Ne and the target torque Te are set based on the required power (step S3).
0). The setting of the operating point is basically set with priority given to the operating efficiency of the engine 150 according to a predetermined map.

FIG. 6 is an explanatory diagram showing an example of the map. FIG. 6 shows the relationship between the engine speed Ne and the torque Te on the horizontal axis.
The vertical axis represents the operating state of the engine 150.
A curve B in FIG. 6 indicates a limit range in which the operation of the engine 150 is possible. The curve α1 to α6 is the engine 15
0 indicates an operation point at which the operation efficiency becomes constant.
The operation efficiency decreases in the order of α1 to α6. Also,
Curves C1 to C3 indicate lines where the power (rotational speed × torque) output from engine 150 is constant.

As shown in FIG. 6, the operation efficiency of the engine 150 greatly differs depending on the rotational speed and the torque. For example, when outputting power corresponding to the curve C1, the engine 150 corresponds to the point A1 in FIG. The operation efficiency is highest when the engine 150 is operated at the operation point (the number of rotations and the torque). Similarly, when power corresponding to curves C2 and C3 is output, the efficiency is highest when the vehicle is operated at points A2 and A3 in FIG. When an operation point at which the operation efficiency is highest is selected for each power to be output, a curve A in FIG. 7 is obtained. This is called an operation curve.

In setting the operating point in step S30, an operation curve obtained experimentally in advance is stored as a map in the ROM, and the required power P is obtained from the map.
e, the operating point corresponding to the
Set the rotation speed and torque of. By doing so, it is possible to set the operation point with the highest operation efficiency.

After setting the operating point of engine 150 in this way, the CPU performs a power generation load control process (step S100). This processing will be described later in detail. As a result of this processing, the load torque applied to the crankshaft 156 by the generator G is determined.

According to the load torque determined in this way,
CPU is clutch motor CM and assist motor AM
Is set (step S200). The setting method of each torque command value is as follows.

The inner rotor 132 of the clutch motor CM
Is coupled to the crankshaft 156 of the engine 150, the absolute value of the output torque of the clutch motor CM is equal to the load torque of the engine 150 based on the principle of action and reaction if the load torque by the generator G is 0. Become equal. Actually, there is a load torque by the generator G. Therefore, the absolute value of the output torque of the clutch motor CM is a value obtained by subtracting the load torque by the generator G from the output torque of the engine 150. However, the symbols are the outer rotor 134 and the inner rotor 13 of the clutch motor CM.
It changes according to the magnitude relation of the number of rotations of 2. When the outer rotor 134 is rotating at a higher rotation speed than the inner rotor 132, the outer rotor 134
32 and the outer rotor 134
, The clutch motor CM is in a power running state, and the torque command value is positive.

On the contrary, the outer rotor 134 is the inner rotor 1
When rotating at a rotation speed lower than 32, the direction in which the outer rotor 134 rotates relative to the inner rotor 132 and the torque applied to the outer rotor 134 are in opposite directions, so that the clutch motor CM enters a regenerative state. , The torque command value becomes negative.

The difference between the rotation speed of the outer rotor 134 and the rotation speed of the inner rotor 132 is determined by the difference between the rotation speed of the outer rotor shaft 135 and the rotation speed of the engine 150. The rotation speed of the outer rotor shaft 135 is uniquely determined by multiplying the rotation speed of the front axle 116 by the gear ratio of the power transmission gear 111. “Rotation speed of engine 150> outer rotor shaft 135
In this case, the clutch motor CM is in a regenerative state. vice versa,
In the case of “the rotation speed of the engine 150 <the rotation speed of the outer rotor shaft 135”, that is, when in the overdrive state, the clutch motor CM is in the power running state.

The torque command value of the assist motor AM is set by the difference between the requested torque and the output torque from the front axle 116. That is, for the required torque,
If the output torque from the front axle 116 is insufficient,
The insufficient torque is the output torque of the assist motor AM. In this case, since the torque output from the front axle 116 is less than the required torque, the assist motor AM is powered and the insufficient torque is output from the rear axle 118. Conversely, when excess torque is output from the clutch motor CM, the torque command value of the assist motor AM becomes negative, and the assist motor AM enters a regenerative state.
The output torque from the front axle 116 can be obtained by multiplying the torque command value of the clutch motor CM by a proportional coefficient according to the gear ratio of the power transmission gear 111.

The operations of the clutch motor CM, the assist motor AM, and the engine are controlled based on the values thus set (step S205). Motor MG1, M
For the control of G2, the control of a well-known synchronous motor can be applied, for example, the control described in JP-A-9-47094 can be applied. Also, the control of the engine 150 is a well-known technique, and a detailed description thereof will be omitted here. The engine 1
The control itself of 50 is executed by the EFIECU 170,
The ECU 190 only outputs various information required for such control.

An example of the torque conversion performed by the above control will be described. FIG. 7 is an explanatory diagram showing a state in which the rotational speed and torque of the power output from engine 150 are converted and output. The power corresponding to the point P1 in FIG. 7, that is, the power consisting of the rotation speed Ne and the torque Te, is output from the engine 150, and this power is output at a low rotation speed and a high torque (P2).
Consider the case where the output is converted to power corresponding to a point).
The curve in FIG. 7 indicates a line where the power given by the number of revolutions × torque is constant. The output torque at point P2 is the sum of the torques output from both drive shafts 116 and 118 coupled to the front and rear wheels, respectively. For simplicity, it is assumed that the gear ratio of the power transmission gear 111 has a value of 1. At this time, if the hybrid vehicle is running in a state in which the front and rear wheels do not slip, the outer rotor shaft 135 and the rear axle 11
8 is a rotation speed Ndf determined according to the vehicle speed.
Matches.

The outer rotor 134 is an inner rotor 132
Is rotated at a rotation speed Ndf lower than the rotation speed Ne, the torque command value of the clutch motor CM is -Te as described above, and the motor is in the regenerative state. At this time, the electric power regenerated by the clutch motor 134 is equal to the product of the rotational speed difference (Ne-Ndf) between the outer rotor 134 and the inner rotor 132 and the torque Te. This corresponds to the area of the portion indicated by G1 in FIG.

The assist motor AM outputs a torque Tdr that is insufficient for the required torque. The output of the torque is performed by powering the assist motor AM. Rear axle 1 with assist motor AM coupled
Since the rotation speed of the motor 18 is Ndf, in order to output the torque, the assist motor AM consumes electric power corresponding to the product of the rotation speed Ndf and the torque Tdr.
This power corresponds to the area of the portion indicated by G2 in FIG.

Generally, the area of G1 and the area of G2 in FIG. 7 are equal. Such a relationship can be easily proved by taking into account the relationship that the power of the points P1 and P2 is constant, that is, the relationship of the number of rotations × torque is constant. This means that assuming that the operation efficiency of the device is 100%, the assist motor AM can be driven by using the electric power obtained by regeneration by the clutch motor CM. In the above example, the power transmission gear 1
The description has been made assuming that the gear ratio of 11 is a value of 1. However, a similar relationship holds when the gear ratio is another value.

Incidentally, if the electric power stored in the battery 194 is used, it is possible to output a torque of Tdr or more from the assist motor AM. At this time, the engine 15
Power that is higher than the power output from 0 is output from the front axle 116 and the rear axle 118. Also, if the power output from the assist motor AM is suppressed, a part of the electric power regenerated by the clutch motor CM will
4 can also be charged. Naturally, it is also possible to output power by regenerating or powering the assist motor AM while powering the clutch motor CM. However, an operation state in which the assist motor AM performs regeneration means that an extra torque that is not required to be output is output, and thus cannot be said to be a preferable operation state in terms of operation efficiency.

Next, the power generation load control processing in this embodiment will be described. FIG. 8 shows the flow of the power generation load control processing routine in this embodiment. In the following description, the gear ratio of the power transmission gear 111 and the reduction gear 113 is assumed to be a value 1 for simplicity. When this routine is started, the CPU reads the engine speed Ne and the drive shaft speed Nd (step S10).
5). The drive shaft is a general term for the front axle 116 and the rear axle 118. Each of these rotation speeds can be detected by a rotation speed sensor. The rotation speed of the engine 150 is
The target rotation speed Ne set in step S30 of FIG. 5 may be used.

The rotation speed Ne of the engine 150 thus detected is compared with the rotation speed Nd of the drive shaft (step S110). Whether the operating state of the power output device corresponds to underdrive or overdrive is determined based on the magnitude relationship between the two. As described above, the clutch motor CM regenerates when the operation state of the power output device is underdrive, and performs power running when it is overdrive. When the clutch motor CM is in regenerative operation, power does not circulate, so that the operating efficiency is not greatly reduced. On the other hand, when the clutch motor CM is in the power running mode, a power circulation occurs in which a part of the power output from the front axle 116 is regenerated by the assist motor AM, and the driving efficiency may be reduced. In order to avoid such a decrease in operating efficiency, it is necessary to perform control so as to avoid a state in which the clutch motor CM becomes power running and the assist motor AM regenerates. In the power generation load control processing routine, the circulation of power during overdrive is reduced by controlling the load by the generator G. Although not shown in FIG. 8 in order to avoid complication of the flowchart, in order to prevent chattering in which the operation state of the generator G is frequently switched in accordance with the determination in step S110, the determination in step S110 is performed. It is desirable to provide a predetermined hysteresis.

As a result of step S 110, “Engine 15
If the rotation speed Ne of 0> the rotation speed Nd of the drive shaft ", that is, in the underdrive state, even if the load by the generator G is 0, the operation efficiency does not decrease due to the circulation of power. . Therefore, the CPU stops the power generation by the generator G (step S130).

On the other hand, in step S110, if "the rotational speed Ne of the engine 150 <the rotational speed Nd of the drive shaft", that is, if the vehicle is in an overdrive state, control for suppressing the circulation of power is performed. First, the distribution of the torque output from the front and rear wheels is set (step S11).
5). As described above, the circulation of power occurs when the assist motor AM is regenerating. Therefore, if the distribution of the torque output from the front and rear wheels is set so that “the torque of the assist motor AM ≧ 0”, the circulation of power does not occur. From the viewpoint of suppressing the circulation of power,
If the absolute value is in a small range, the power distribution may be set including the range of “torque of assist motor AM <0”. Since the rotation speeds of the front axle 116 and the rear axle 118 are determined according to the vehicle speed, setting the power distribution is nothing but setting the torque distribution.

Based on the power distribution thus set,
Next, a power generation load is set according to the following procedure (step S120). In step S115, the torque output from the front axle 116 is set. This torque is equal to the torque of the inner rotor shaft 133 in consideration of the principle of the action reaction. On the other hand, the output torque from engine 150 is set in step S30 in FIG. The output torque of engine 150 is equal to the sum of the torque of inner rotor shaft 133 and the load torque generated by generator G. Therefore, "Engine 1
By calculating "50 target torque Te-torque of inner rotor shaft 133", the power generation load torque can be obtained.

The CPU performs power generation while controlling the generator G so that the power generation load is applied to the crankshaft 156 (step S125). Specifically, the duty of the transistor forming the drive circuit 193 of the generator G is controlled. In the above description, the power transmission gear 111
And the gear ratio of the reduction gear 113 is assumed to be a value of 1. However, when these gear ratios are different from the value 1, the rotational speed and the torque of the drive shaft are multiplied by a proportional coefficient corresponding to the gear ratio. , The above-described control can be realized.

According to the power output device described above, by controlling the power generation load by the generator G, it is possible to suppress the circulation of power generated during overdrive. Therefore, the operation efficiency of the power output device can be improved. Moreover, the power output device of the present embodiment has an advantage that such control can be realized with a very simple configuration. That is, in the power output device of the present embodiment, the configuration required to suppress the circulation of power during overdrive is the generator G and the drive circuit 193 thereof. The drive circuit 193 has a very simple configuration as compared with the drive circuits 191 and 192 of the clutch motor CM and the assist motor AM (see FIGS. 2 and 3).
Also, there is no need to provide a mechanically movable part unlike a clutch. Therefore, according to the power output device of the present invention, the operation efficiency can be improved without extremely increasing the size, weight, and manufacturing cost of the power output device as compared with the conventional power output device. This is particularly advantageous when applied to a vehicle having very strict restrictions on the space and weight for mounting the device.

The generator G of this embodiment can be used as a starter. For example, when the transistor T of the drive circuit 193 (FIG. 3) is turned on and a current flows when the engine 150 is stopped, the generator G is driven as a motor. Crankshaft 1 by rotation of generator G
56 can be rotated, and cranking for starting the engine 150 can be performed. Therefore, if the power output device of this embodiment is mounted, the normal engine 15
There is also an advantage that the starter motor provided at 0 can be omitted.

In a hybrid vehicle, for example, since it is possible to drive by driving only the assist motor AM, the engine 150 may be stopped even when the vehicle is running. Therefore, while the vehicle is running, the engine 15
It may be necessary to start 0. Also in such a case, cranking of the engine 150 can be performed by making the generator G in this embodiment function as a starter. Of course, cranking of the engine 150 can be performed even when the clutch motor CM is run. However, when the cranking is performed by powering the clutch motor CM, the torque is also transmitted to the front axle 116,
Since a shock or the like may occur, it is necessary to separately take measures for canceling the shock.
In this embodiment, if the clutch motor CM is set in the free-run state, there is an advantage that such a shock does not occur even if the generator G is used as a starter.

On the other hand, as described above, in this embodiment, the configuration of the drive circuit 193a (FIG. 4) for the generator G can be adopted. When the drive circuit 193a having such a configuration is used, it is not possible to control the power generation load of the generator G. Therefore, the content of the power generation load control processing routine (FIG. 8) changes. In this case, in the power generation load control processing routine, only whether or not to generate power by the generator G is controlled. That is, steps S115 and S1 in FIG.
This is a control routine in which step 20 is omitted. When such a configuration is employed, the power generation load has a predetermined constant value. Even in such a case, the circulation of power can be suppressed, so that the operation efficiency can be improved. At this time, the power generation load is
If the load is set such that “torque of assist motor AM ≧ 0”, the effect of improving the operating efficiency is further increased. Further, when the driving circuit 193a is employed, there is a great advantage that the processing contents of the power generation load control processing routine can be simplified. The simplification of the processing makes it possible to control the power generation load at a high speed, and it is possible to greatly improve the responsiveness to the frequently changing running state of the vehicle.

(3) Second aspect: As a second aspect of the hybrid vehicle having the above configuration, a configuration using a planetary gear 120 and a motor generator MG instead of the clutch motor CM (FIG. 1). It can also be taken. FIG. 9 shows the configuration of the hybrid vehicle according to the second embodiment.
Shown in

The planetary gear 120 is provided with the sun gear 12
1. A planetary carrier 123 including two coaxial gears, ie, a ring gear 122, and a plurality of planetary pinion gears disposed between the sun gear 121 and the ring gear 122 and revolving around the sun gear 121 while rotating. You. As shown in FIG. 9, the rotor of the motor generator MG is connected to the sun gear 121 of the planetary gear 120. On the planetary carrier 123, the crankshaft 156 of the engine 150 is mounted on the damper 130.
Are coupled through. The power transmission gear 111 is connected to the ring gear 122. Other configurations are the same as in the first embodiment (FIG. 1).

As for the rotational speed of each gear of the planetary gear 120, the relationship expressed by the above-described equation (1) is naturally satisfied. Further, as is well-known in mechanics, the relationship expressed by the following equation holds for the torque input / output to each gear. Ts = Tc × ρ / (1 + ρ): Tr = Tc / (1 + ρ): where Ts is the torque of the sun gear 121, Tc is the torque of the planetary carrier 123, and Tr is the ring gear 122.
Means the torque. Ρ is the ring gear 122
And the gear ratio of the sun gear 121.

As is clear from the above equation, when the torque output from the engine 150 is input from the planetary carrier 123 to the planetary gear 120, the torque is applied to the sun gear 121 and the ring gear 122 at a constant rate determined by the gear ratio ρ. Is output.

On the other hand, the torque output from sun gear 121 drives motor generator MG coupled thereto to generate electric power. In the second embodiment, the engine 150
In that a part of the power output from the clutch motor CM can be converted into electric power. As described above, the hybrid vehicle according to the second embodiment in which the clutch motor CM according to the first embodiment is replaced with the generator G and the planetary gear 120,
It can be seen that the hybrid vehicle according to the first embodiment has the same function as the hybrid vehicle.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and can be implemented in various forms without departing from the gist of the present invention. Of course. For example, in the above-described embodiment, the case where the power output device is applied to a hybrid vehicle has been described as an example, but the present invention is not limited to a hybrid vehicle, but may be applied to various devices that are required to output power from two output shafts It is possible to apply.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of a vehicle equipped with a power output device as an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a schematic configuration of a first driving circuit 191.

FIG. 3 is an explanatory diagram showing a first configuration of a third drive circuit 193.

FIG. 4 is an explanatory diagram showing a second configuration of the third drive circuit 193.

FIG. 5 is a flowchart showing a flow of a torque control routine.

FIG. 6 is an explanatory diagram showing setting of operating points of engine 150.

FIG. 7 is an explanatory diagram showing a state of torque conversion by the power output device of the present invention.

FIG. 8 is a flowchart showing a flow of a power generation load control processing routine.

FIG. 9 is an explanatory diagram showing an overall configuration of a vehicle equipped with a power output device of another embodiment.

FIG. 10 is an explanatory diagram showing the overall configuration of a conventional hybrid vehicle capable of four-wheel drive.

[Explanation of symbols]

 Reference Signs List 22 drive shaft 23 transmission gear 24 differential gear 26, 27, 28, 29 drive wheel 30 clutch motor 32 outer rotor 34 inner rotor 40 electric motor 50 motor 80 control device 91, 92 drive circuit 94 Battery 111 Power transmission gear 113 Reduction gear 114 Differential gear 115 Differential gear 116 Front axle 116R, 116L Front wheel 118 Rear axle 118R, 118L Rear wheel 120 Planetary gear 121 Sun gear 122 Ring gear 123 Planetary carrier 130 damper 132 inner rotor 133 inner rotor shaft 134 outer rotor 135 outer rotor shaft 142 rotor 144 stator 146 rotor 148 stator 150 engine 15 6 Crankshaft 170 EFI ECU 190 Control unit (ECU) 191, 192, 193 Drive circuit 194 Battery CM Clutch motor AM Assist motor G Generator Generator MG Motor generator

Claims (10)

[Claims] A power output device having a first output shaft, a second output shaft, and a motor, and capable of outputting power output from the motor from the first output shaft and the second output shaft. Power transmission means coupled to the output shaft of the prime mover and the first output shaft, and capable of increasing / decreasing power output from the prime mover by exchanging electric power and transmitting the power to the first output shaft; An electric motor coupled to the second output shaft and capable of inputting / outputting power to / from the second output shaft; and controlling the operation of the motor, the power transmission means, and the electric motor to output the electric power from the first output shaft. Power control means for making the sum of the power output from the second output shaft and the power output from the second output shaft equal to the requested power. The power output from the prime mover is transmitted to the first output shaft. Generator provided in the power transmission path A drive circuit for generating electric power by the generator; a detection unit for detecting a rotation speed of the prime mover; a detection unit for detecting a rotation speed of the first output shaft; and controlling a drive circuit of the generator. When the rotation speed of the prime mover is smaller than the rotation speed of the first output shaft, a predetermined load is applied to the power transmission path by regenerating part of the power output from the prime mover as electric power. And a power generation control unit. 2. The power output device according to claim 1, wherein the power generator is a power generator capable of changing a power generation load, and the predetermined load is a second power output as a result of control by the power control means. A power output device that is a load capable of setting an output torque of a motor coupled to an output shaft to a value of 0 or more. 3. The power output device according to claim 1, wherein the generator is a DC generator. 4. The power output device according to claim 1, wherein the power transmission means includes: a first rotor coupled to an output shaft of the prime mover; and the first output shaft. And a second rotor that is rotatable relative to the first rotor. The power is supplied through electromagnetic coupling and relative sliding that occurs between the first rotor and the second rotor. The power output device is means for increasing / decreasing power output from the prime mover and transmitting the power to the first output shaft. 5. The power output device according to claim 1, wherein the power transmission unit is provided separately from the generator, and includes a motor generator having an input shaft; An output shaft, the first output shaft, and three shafts respectively coupled to the input shaft. When power to be input to or output from two of the three shafts is determined, input and output are performed from the remaining one of the shafts. Power output device comprising power input / output means for determining the power to be supplied. 6. A power output capable of outputting power output from the prime mover using at least a prime mover and an electric motor from the front axle and the rear axle using a front axle coupled to the front wheels and a rear axle coupled to the rear wheels. And a power output device, coupled to an output shaft of the prime mover and the front axle, to increase or decrease the power output from the prime mover by exchanging electric power. A power transmission means capable of transmitting power to the front axle; an electric motor coupled to the rear axle, capable of inputting and outputting power to the rear axle; and controlling the operation of the prime mover, the power transmission means, and the electric motor, and Power control means for making the sum of the power output from the motor and the power output from the rear axle equal to the requested power, and the power output from the prime mover is A generator provided in a power transmission path transmitted to an axle; a drive circuit for generating power by the generator; a detection unit for detecting a rotation speed of the prime mover; and detecting a rotation speed of the front axle. By controlling the detection means and the drive circuit of the generator, when the rotation speed of the prime mover is smaller than the rotation speed of the front axle, by regenerating a part of the power output from the prime mover as electric power, A hybrid vehicle that is a power output device including: a power generation control unit that applies a predetermined load to the power transmission path. 7. The hybrid vehicle according to claim 6, wherein the generator is a generator capable of changing a power generation load, and the predetermined load is coupled to a rear axle as a result of control by the power control means. A hybrid vehicle having a load that can make the output torque of the electric motor to be equal to or greater than 0. 8. The hybrid vehicle according to claim 6, wherein the generator is a DC generator. 9. A motor, which is coupled to a first output shaft and a second output shaft, a prime mover, and an output shaft of the prime mover and the first output shaft, and increases / decreases power output from the prime mover by exchanging electric power. A power transmission means capable of transmitting power to the first output shaft, an electric motor coupled to the second output shaft and capable of inputting and outputting power to and from the second output shaft, and a power output from the prime mover And a generator provided on a power transmission path transmitted to the first output shaft, and a power output capable of outputting power output from the prime mover from the first output shaft and the second output shaft. A control method for controlling operation of a device, comprising: (a) detecting a rotation speed of the prime mover;
(B) detecting the number of revolutions of the first output shaft;
(C) when the rotation speed of the prime mover is lower than the rotation speed of the first output shaft, a part of the power output from the prime mover by the generator is regenerated as electric power and a predetermined power is transmitted to the power transmission path. And (d) changing the sum of the powers output from the first output shaft and the second output shaft according to the load by the generator so that the sum of the powers matches the required power. Controlling the operation of the prime mover, the power transmission means, and the electric motor. 10. The control method according to claim 9, wherein the operation of a power output device including a generator capable of changing a power generation load is controlled, wherein the step (c) includes: (c-1) the step (d). And (c-2) a step of: (c-2) regenerating electric power from the generator using the load.