JP2008012990A - Hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hybrid vehicle which can raise fuel consumption efficiency of a vehicle further at steady traveling time. <P>SOLUTION: In a driving force property of a hybrid vehicle, a speed reduction ratio by engine driving is assumed to be fixed. The speed reduction ratio is set so that it can accelerate only up to the highest vehicle speed V<SB>4</SB>at maximum output time of the engine at steady traveling time, and cannot accelerate to the highest speed V<SB>max</SB>of the hybrid vehicle. At steady traveling time where the vehicle speed is V<SB>1</SB>to V<SB>4</SB>, it travels with engine driving force in principle. From vehicle speed V<SB>4</SB>to the maximum speed V<SB>max</SB>, desired vehicle speed is realized by motor driving. Fuel consumption efficiency can be raised since engine load at steady traveling time is reduced by setting of such a speed reduction ratio and utilization of travel modes. When low output is achieved by an engine output characteristics change mechanism, for example, at cylinder asleep operation of the engine, output becomes as shown by a characteristic curve d which indicates the engine driving force property and the fuel consumption efficiency can be raised further. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hybrid vehicle that travels by combining the engine driving force of an engine (internal combustion engine) and the motor driving force of a motor (electric motor), and in particular, a first transmission path for transmitting engine driving force to driving wheels and motor driving. The present invention relates to a hybrid vehicle including a second transmission path that transmits force to driving wheels.

Conventionally, by using the driving force characteristics of the engine and the motor, the vehicle travels by a second transmission path that transmits the motor driving force to the driving wheels in a vehicle speed range below a certain fixed speed (vehicle speed V ₁ ). in V ₁ or more vehicle speed ranges travels using both the first transmission path for transmitting the second transmission path and the engine driving force to the drive wheel primarily first by the engine in the vicinity of the maximum velocity V _max A hybrid vehicle that travels using a transmission path is known. In this hybrid vehicle, determined gear ratio of the first transmission path such that the characteristic driving force characteristics of the engine can cover the maximum speed V _max, the variable of the second transmission path and the first transmission path without simplified by providing a transmission having a gear ratio, is close to the maximum velocity V _max is set to be traveling is transmitted to the drive wheels to the engine driving force at the first transmission path (see Patent Document 1).
Japanese Patent No. 2942533 (see paragraph numbers 0015 to 0028 and FIGS. 1 and 2)

However, in the configuration of the hybrid vehicle disclosed in Patent Document 1, during steady driving (cruising) with a low load, the vehicle travels in a series operation mode in which power is generated by an engine and driving wheels are driven by a motor, or the maximum speed is reached. The vehicle travels with the engine driving force using the first transmission path including the transmission device with a relatively large reduction ratio (low ratio gear ratio) set to achieve V _max with the engine driving force. .

However, in the series operation mode, since the transmission efficiency of the driving force is relatively low, the fuel efficiency of the vehicle may be reduced. Furthermore, when traveling only by the engine driving the first transmission path including a transmission gear ratio of Roureshio, in the gear ratio of Roureshio set in order to realize the driving force characteristics of the engine can achieve maximum velocity V _max The engine speed greatly changes according to the vehicle speed of steady running, and the engine running speed range with high fuel efficiency cannot be selected and steady running cannot be performed, so that the fuel efficiency is lowered.

In particular, in the combination of engine drive and motor drive in a hybrid vehicle equipped with a large displacement engine, since it is a large displacement engine, the marginal driving force is large, and the transmission device with the low ratio gear ratio setting as described above is used. In the first transmission path including the fuel efficiency, the fuel efficiency may be significantly reduced. Further, in the case of a combination with such a large displacement engine, even if an attempt is made to improve fuel efficiency by combining an output characteristic variable mechanism such as cylinder deactivation with a large displacement multi-cylinder engine, When the low ratio gear ratio is set, it is not possible to sufficiently bring out the merits of the variable cylinder output characteristic mechanism for improving the fuel efficiency.
The present invention has been made in view of the above problems, and an object thereof is to provide a hybrid vehicle that can further improve the fuel efficiency of the vehicle.

  A hybrid vehicle according to a first aspect of the present invention includes a first transmission path for transmitting an engine driving force of an engine to driving wheels, and a second transmission path for transmitting a motor driving force of a motor to driving wheels. The first reduction gear ratio of the first transmission path is higher than the reduction gear ratio when the maximum speed achievable by the vehicle is obtained only by the engine driving force. Is also set to be small.

  Since the reduction ratio of the first transmission path is set to such an extent that the maximum speed cannot be obtained only with the engine driving force, the engine rotation speed is good for engine combustion efficiency during steady running at a normal vehicle speed lower than the maximum speed. You can drive in the vicinity. Of course, when the maximum speed is to be achieved, series operation in which electric power is generated by the engine and the motor is driven by the electric power, or parallel operation by engine driving and motor driving may be performed.

  In the hybrid vehicle according to the second aspect of the present invention, when the vehicle achieves the maximum speed, only the motor driving force is transmitted to the driving wheels through the second transmission path, or the motor driving force is transmitted to the second transmission path. And transmitting the engine driving force to the driving wheel through the first transmission path.

  The hybrid vehicle of the invention according to claim 3 further includes an output characteristic variable mechanism in which the engine varies the output characteristic, and the first transmission path has a reduction ratio smaller than the first reduction ratio, and the output characteristic. When the output is reduced by the variable mechanism, the second reduction ratio can be set so that the driving force can be smaller than the driving force that can be achieved at the maximum output when the output of the engine is reduced by the first reduction ratio. It has a transmission gear.

  The hybrid vehicle according to a fourth aspect of the invention is further characterized in that the output characteristic varying mechanism performs a cylinder deactivation operation in which some cylinders are deactivated during operation of the engine.

  The hybrid vehicle of the invention according to claim 5 is further characterized in that the output characteristic varying mechanism performs at least one of valve opening / closing control, ignition timing control, and fuel injection control.

  A hybrid vehicle according to a sixth aspect of the present invention includes a first transmission path for transmitting the engine driving force of the engine to the driving wheels, and a second transmission path for transmitting the motor driving force of the motor to the driving wheels. The first reduction ratio of the first transmission path is a reduction ratio when the vehicle achieves the maximum speed that can be achieved by only the engine driving force. The first transmission path and the second transmission path include a common output gear that transmits at least one of the engine driving force and the motor driving force to the driving wheels, and includes a vehicle stop state. In a first vehicle speed range including a first vehicle speed higher than the first vehicle speed and a maximum speed achievable by the vehicle, at least the motor driving force is transmitted to the driving wheels through the second transmission path, and the second vehicle speed is lower than the first vehicle speed. car From the second speed range to less than the first vehicle speed, the time of steady running, characterized in that to transmit to the drive wheels by the first transmission path of the engine driving force.

  According to the first aspect of the present invention, it is possible to obtain a hybrid vehicle capable of realizing a traveling state with good fuel efficiency.

  Further, according to the invention described in claim 2, the hybrid vehicle can easily travel at the maximum speed by assisting the engine drive by the motor drive or by generating electric power from the engine and driving the motor with the electric power. Can do.

According to a third aspect of the present invention, the engine has an engine output characteristic variable mechanism, and the first transmission path has a speed change ratio that can be set to a second reduction ratio smaller than the first reduction ratio. In the case of traveling at the second reduction ratio with a gear provided, steady traveling is performed only up to a vehicle speed lower than the vehicle speed that can be achieved by the first reduction ratio at the maximum output when the output is reduced by the output characteristic variable mechanism. Therefore, for example, when the cylinder deactivation operation is performed by the output characteristic variable mechanism when the vehicle travels at a medium speed, setting the second reduction ratio can maintain the engine rotation speed in a state with good fuel efficiency, and the cylinder deactivation operation. The benefits of fuel efficiency can be extracted.
In the invention of claim 3, the output characteristic variable mechanism can combine valve opening / closing control, ignition timing timing control, fuel injection control, and the like in addition to cylinder deactivation operation control. It can be a good hybrid vehicle.

  According to the sixth aspect of the present invention, the first speed reduction ratio of the first transmission path is set smaller than the speed reduction ratio when the maximum speed that can be achieved by the vehicle is obtained only by the engine driving force. For example, in the first vehicle speed range from the highest vehicle speed that can be realized only by the engine driving force to the maximum speed of the hybrid vehicle, the driving power is assisted by the motor driving force or the electric power generated by the engine driving is generated. In the second high-speed / medium-speed vehicle speed range that does not include the maximum speed, only the engine driving force is used for steady-state driving, so the engine speed depends on the first reduction ratio. Therefore, the fuel efficiency can be improved over the conventional hybrid vehicle described in Patent Document 1.

<< First Embodiment >>
Hereinafter, the hybrid vehicle according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
FIG. 1 is a schematic diagram of the entire hybrid vehicle according to the present embodiment, and shows a transmission path of driving force of a motor and an engine by a fixed gear. FIG. 2 is a driving force characteristic diagram in the hybrid vehicle of the present embodiment. In FIG. 2, the horizontal axis indicates the vehicle speed, and the vertical axis indicates the driving force or the running resistance.
The hybrid vehicle 50A according to the present embodiment travels the vehicle by transmitting the driving force of the engine 1 to the driving wheels 6 to travel the vehicle and the driving force of the motor 8 to the driving wheels 6. The second transmission path is configured to travel with the first transmission path and the second transmission path alternatively selected or combined.

Next, the first transmission path will be described. As shown in FIG. 1, an output shaft 2 of an engine 1 composed of multiple cylinders, for example, 6 cylinders, is directly connected to a generator 4 that also serves as a cell motor via a flywheel 3. Is connected to a clutch 5A for transmission to the motor.
The first transmission path is driven coaxially with the output shaft 2, the clutch 5A, the main gear 11 connected to or disconnected from the output shaft 2 by the clutch 5A, the output gear 12 meshing with the main gear 11, and the output gear 12. Pinion gear 13, a final gear 14 that meshes with the pinion gear 13, and a differential gear 7 that is input from the final gear 14 and drives the drive wheels 6. The driving force of the engine 1 is transmitted to the drive wheels 6 through this first transmission path.
The first transmission path has a fixed first reduction gear ratio determined by the product of the gear ratio between the main gear 11 and the output gear 12 and the gear ratio between the pinion gear 13 and the final gear 14. It does not have a transmission with a gear ratio. The main gear 11, the output gear 12, the pinion gear 13, and the final gear 14 constitute a speed reducer 9 </ b> A for driving the driving wheels 6 by the engine 1.

Here, the first reduction ratio of the reduction gear 9A is set as follows. As shown in the characteristic curve a of FIG. 2, the driving force characteristic of the hybrid vehicle 50A at the time of steady running when the engine 1 is in a steady state is as follows. at the highest speed V _max vicinity, the driving force than the running resistance characteristic curve b is below, it is set to a level of the driving force put out only until the vehicle speed V _4. In other words, only the driving force of the engine 1 gear ratio of the reduction gear 9A so prohibitive maximum velocity V _max is set.
The running resistance characteristic curve b in FIG. 2 is obtained by adding the rolling resistance of the drive wheels 6 and the resistance that increases according to the vehicle speed, such as air resistance.

Next, the second transmission path will be described. As shown in FIG. 1, the motor 8 driven by being supplied with electric power from the generator 4 or the battery 20 via the inverter 21 has an input gear 8 b directly connected to the motor shaft 8 a meshed with the main gear 11.
The second transmission path includes an input gear 8b, a main gear 11, an output gear 12 meshed with the main gear 11, a pinion gear 13 driven coaxially with the output gear 12, a final gear 14 meshed with the pinion gear 13, and The differential gear 7 is inputted from the final gear 14 and drives the drive wheels 6. The driving force of the motor 8 is transmitted to the drive wheels 6 through this second transmission path.
The second transmission path is a fixed reduction ratio determined by the product of the gear ratio between the input gear 8b and the main gear 11, the gear ratio between the main gear 11 and the output gear 12, and the gear ratio between the pinion gear 13 and the final gear 14. And does not have a transmission with a variable gear ratio.

The maximum output characteristic of the motor 8 is shown in the maximum output characteristic curve c of FIG. The maximum output characteristic curve c becomes the maximum driving force from the start of the hybrid vehicle 50A to a predetermined low vehicle speed, and thereafter, the driving force rapidly increases as the vehicle speed increases, that is, as the rotational speed of the motor 8 increases. Go down to. However, in the vicinity of the maximum speed V _max of the hybrid vehicle 50A, the maximum output characteristic of the motor 8 exceeds the running resistance characteristic curve b, and the motor 8 is driven so that the motor 8 can be driven to the maximum speed V _max alone. Force characteristics are set.

As shown in FIG. 1, a hybrid ECU (ECU: Electric Control Unit) 23A is provided for controlling the operating state of the hybrid vehicle 50A. The hybrid ECU 23A includes an ignition switch signal from an ignition switch 35, a shift position signal from a shift lever position sensor 36 provided on a shift lever (not shown), and an accelerator pedal position sensor provided on an accelerator pedal (not shown). 37, an accelerator pedal depression amount signal from 37, a brake pedal depression amount signal from a brake pedal position sensor 38 provided on a brake pedal (not shown), and a vehicle speed signal from a vehicle speed sensor 39 provided on a wheel are input.
The battery 20 is provided with various sensors (not shown) that detect the output voltage, the output current, and the battery temperature, and the various sensor signals are input to the hybrid ECU 23A.
The hybrid ECU 23A controls the actuator 33A that connects or disconnects the clutch 5A in response to the accelerator pedal depression amount and the brake pedal depression amount based on the vehicle speed signal.

The hybrid ECU 23A controls the generator 4 also serving as a cell motor and the motor 8 capable of generating power via the inverter 21 and controls the operation of the engine 1 via the engine ECU 25 that controls the output characteristic variable mechanism 31 and the like. .
The hybrid ECU 23A and the engine ECU 25 are connected via a communication line. In addition to the control signal from the hybrid ECU 23A, the engine ECU 25 has a shift position signal, an accelerator pedal depression signal, a brake pedal depression signal, a vehicle speed. A signal is input. Conversely, the engine ECU 25 detects the rotational speed of the engine 1 and outputs it to the hybrid ECU 23A via a communication line.

The output characteristic variable mechanism 31 is, for example, a mechanism for variably controlling the lift amount and opening / closing timing of a valve (not shown) provided in the cylinder 1a of the engine 1, and a variable for stopping the cylinder without driving the valves of some cylinders 1a. It includes a mechanism for performing cylinder control (cylinder deactivation operation), an electronic circuit for controlling the timing of ignition timing, a mechanism for performing fuel injection control, and an electronic circuit.
The characteristic curve d in FIG. 2 shows the engine 1 in the case of the cylinder deactivation operation in which three cylinders in one bank of the six-cylinder engine 1 are deactivated by the operation of the output characteristic variable mechanism 31 and only the remaining three cylinders are operated. The driving force characteristics in the almost maximum output state are shown. Only low-output to an engine driving force by such cylinder deactivation operating state, but as it only until the vehicle speed V ₃ in the first reduction ratio.

(Transmission path switching control)
In the above configuration, the hybrid ECU 23A switches the first transmission path and the second transmission path in accordance with the vehicle speed as described below and causes the hybrid vehicle 50A to travel.
In the low vehicle speed range including when starting from the vehicle speed 0 to less than the vehicle speed V ₁ (second vehicle speed) shown in FIG. 2 and when traveling uphill, the actuator 33A is controlled so that the output shaft on the engine 1 side is controlled by the clutch 5A. 2 and the main gear 11 are separated from each other, the inverter 21 is controlled, and the driving wheel 6 is driven by the motor 8 through the second transmission path. At this time, the motor 8 is driven by electric power from the battery 20. If the state of charge of the battery 20 is low, the hybrid ECU 23A controls the inverter 21 and the engine ECU 25 to activate the engine 1 by causing the generator 4 to function as a cell motor. Then, the inverter 21 is controlled, the engine 1 causes the generator 4 to generate electric power, and the motor 8 is driven by the electric power (series operation mode).
The maximum output characteristic of the motor 8 is as shown by the maximum output characteristic curve c in FIG. 2 and has a driving force that exceeds the running resistance characteristic curve b. The vehicle can travel in the vehicle speed range.

Vehicle speeds _{V 1} to the vehicle speed _{V 4} from the steady running of the (first vehicle speed) high speed range, in the to less than (the second vehicle speed range), the hybrid ECU23A the engine 1 side to the clutch 5A by controlling the actuator 33A Since the inverter 21 is not allowed to drive the motor 8 in principle, only the driving force of the engine 1 is transmitted to the drive wheels 6 through the first transmission path. The driving force of the driving wheel 6 at this time follows the characteristic curve a or the characteristic curve d shown in FIG. In the case of cylinder deactivation operation, because only put out until the vehicle speed V ₃ in the range of the driving force exceeding the running resistance characteristic curve b, the engine ECU25 includes vehicle speed and a shift position signal, in accordance with the accelerator pedal depression amount signal, The output characteristic variable mechanism 31 is controlled so as to obtain the best fuel consumption, and the 6-cylinder operation and the 3-cylinder operation are selectively used and switched.
At this time, the motor 8 rotates with rotation (idling).

When the vehicle speed V ₁ of the acceleration at the time of running at high speed, in a to less than V _4, hybrid ECU23A controls the inverter 21 to assist the engine driving the motor 8, when the deceleration conversely The hybrid ECU 23A controls the inverter 21 to cause the motor 8 to generate regenerative power.

Next, in the maximum vehicle speed range (first vehicle speed range) from V ₄ (first vehicle speed) where the vehicle speed is high to the maximum speed V _max , the hybrid ECU 23A controls the actuator 33A to engine the clutch 5A. The driving force of the engine 1 is transmitted to the driving wheels 6 through the first transmission path, and the motor 21 is rotated by controlling the inverter 21 to drive the motor 8. The force is transmitted to the drive wheel 6 through the second transmission path. That is, a parallel operation mode in which driving by the engine 1 is assisted by the motor 8 is set. At this time, when the state of charge of the battery 20 is small, the hybrid ECU 23A controls the inverter 21 to generate power with the generator 4 and drives the motor 8 with the electric power.

(Effects of the first embodiment)
According to this embodiment, the hybrid vehicle 50A, in the low vehicle speed range from the vehicle speed zero to a predetermined below the vehicle speed V _1, can be from a higher driving force motor 8 to obtain a driving force of a maximum output characteristic curve c In this low vehicle speed range, the motor 8 can easily travel with a large driving force. Accordingly, the present invention can also be used for traveling that requires a driving force such as traveling on a slope. When the vehicle speed increases and the vehicle travels in the middle / high vehicle speed range (second vehicle speed range) from the vehicle speed V ₁ (second vehicle speed) to less than V ₄ (first vehicle speed), the characteristic curve a Alternatively, as indicated by the characteristic curve d, the driving force characteristic of the engine 1 exceeds the running resistance characteristic curve b, so that the engine 1 can run alone.

As shown in FIG. 2, the characteristic curve a in the present embodiment indicates that the first transmission path is decelerated so that the maximum speed V _max of the hybrid vehicle 50 </ b> A can be achieved only by the conventional engine driving force described in Patent Document 1. Since the driving force is smaller than the characteristic curve f of the driving force of the engine 1 when the ratio is set and the engine is operated at a lower rotation and a higher load with respect to the same running resistance, the conventional hybrid described in Patent Document 1 is used. Fuel consumption is improved compared to vehicles. Furthermore, in the case of flat ground travel where no driving force is required, it is possible to travel even with the drive characteristics in the cylinder deactivation operation as shown by the characteristic curve d, and it is possible to perform steady travel with better fuel consumption.
In particular, the combination of engine driving and motor driving in a hybrid vehicle 50A equipped with a large displacement engine as the engine 1 has a large driving capacity because it is a large displacement engine during steady running, but the gear ratio of the reducer 9A is large. However, the gear ratio is set to a higher ratio than the conventional hybrid vehicle, and the fuel efficiency is remarkably improved as compared with the conventional hybrid vehicle. Further, in the case of a combination with such a large displacement engine, a large displacement multi-cylinder engine is combined with an output characteristic variable mechanism 31 including a cylinder deactivation function to reduce engine output and improve combustion efficiency. The fuel efficiency can be improved by setting the engine speed.

Since the maximum vehicle speed range (first vehicle speed range) from the vehicle speed V ₄ (first vehicle speed) to the maximum speed V _max cannot be obtained with the driving force of the engine 1 alone, The desired vehicle speed can be realized by assisting the engine driving force with the driving force of the motor 8 through the transmission path.
Incidentally, transmitted at the highest speed range of the vehicle speed V ₄ to a maximum velocity V _max, the clutch 5A is the output shaft 2 of the engine 1 side in the non-connected state with the main gear 11, only the driving force of the motor 8 to the driving wheels 6 It is good also as a series operation mode.

<< Second Embodiment >>
Next, a hybrid vehicle according to a second embodiment of the present invention will be described with reference to FIGS. 3 and 4 (refer to FIG. 2 as appropriate).
FIG. 3 is a schematic diagram of the entire hybrid vehicle of the present embodiment, and shows a transmission path for the driving force of the motor and engine.
The hybrid vehicle 50B of the present embodiment travels the vehicle by transmitting the driving force of the engine 1 to the driving wheels 6 to travel the vehicle and the driving force of the motor 8 transmitted to the driving wheels 6. A hybrid vehicle 50B configured to travel by selectively selecting or using the first transmission route and the second transmission route together. A difference from the hybrid vehicle 50A in the first embodiment is that a planetary gear (speed change) can be used as a transmission capable of switching between two gear ratios of direct connection and acceleration instead of the clutch 5A of the first embodiment. Gear) 10 is combined. The planetary gear 10 includes an actuator 33B that disconnects the output shaft 2 from the first transmission path and controls the reduction ratio of the planetary gear 10, and a clutch 5B and a clutch plate brake that are driven by the actuator 33B. 5C is provided.

  Next, the connection state of the planetary gear 10 will be described in more detail. The output shaft 2 is directly connected to a planetary carrier 17 that holds the pinion gear 16 of the planetary gear 10. The shaft of the sun gear 15 that meshes with the pinion gear 16 can be connected to and disconnected from the output shaft 2 via the clutch 5B, and can be switched between rotation and stop via the clutch plate brake 5C. The shaft of the ring gear 18 facing inwardly engaged with the pinion gear 16 is directly connected to the motor shaft 8a. 11 meshes with the output gear 12.

Next, the first transmission path will be described. As shown in FIG. 3, the output shaft 2 of the 6-cylinder engine 1 is directly connected to a generator 4 that also serves as a cell motor via a flywheel 3, and further transmits the driving force of the engine 1 to the drive wheels 6. Is connected to the clutch 5B.
The first transmission path includes an output shaft 2, a clutch 5B, a main gear 11 provided in the planetary gear 10 connected to or disconnected from the output shaft 2 by the clutch 5B, an output gear 12 meshing with the main gear 11, A pinion gear 13 that is driven coaxially with the output gear 12, a final gear 14 that meshes with the pinion gear 13, and a differential gear 7 that is input from the final gear 14 and drives the drive wheels 6. The driving force of the engine 1 is transmitted to the drive wheels 6 through this first transmission path.
The planetary gear 10, the main gear 11, the output gear 12, the pinion gear 13, and the final gear 14 constitute a speed reducer 9 </ b> B for driving the driving wheels 6 by the engine 1.

  The reduction ratio of the first transmission path can be switched between two reduction ratios as follows depending on the operating states of the clutch 5B and the clutch plate brake 5C. First, when the clutch 5B is on (ON) and the clutch plate brake 5C is off (OFF), the shaft of the sun gear 15 of the planetary gear 10 and the shaft of the planetary carrier 17 are fixed by the clutch 5B. And since the sun gear 15 and the planetary carrier 17 rotate integrally, the reduction gear ratio of the planetary gear 10 is 1. Also in the present embodiment, the reduction ratio determined by the product of the gear ratio between the main gear 11 and the output gear 12 and the gear ratio between the pinion gear 13 and the final gear 14 is the same as that in the first embodiment. Reduced ratio. That is, the drive characteristics of the engine 1 based on the first reduction ratio of the speed reducer 9B are set in the same way as in the first embodiment.

  Next, when the clutch 5B is off (OFF) and the clutch plate brake 5C is on (ON), the shaft of the sun gear 15 of the planetary gear 10 is stopped by the clutch plate brake 5C, and the planetary carrier 17 Along with the rotation around the sun gear 15, the pinion gear 16 rotates in the same direction as the rotation direction of the planetary carrier 17, and the ring gear 18 is accelerated in the same rotation direction. The speed reduction ratio of the first transmission path is the speed reduction ratio between the planetary carrier 17 and the ring gear 18 in the speed-up state, the gear ratio between the main gear 11 and the output gear 12, and the gear between the pinion gear 13 and the final gear 14. The second reduction ratio is smaller than the first reduction ratio determined by multiplying the ratios.

The second speed reduction ratio is a speed reduction ratio smaller than the first speed reduction ratio, and the drive characteristic of the engine 1 based on the second speed reduction ratio is like the drive characteristic at the time of six-cylinder operation shown by the characteristic curve e in FIG. to lower than the maximum vehicle speed V ₃ of the engine 1 is realized based on the state of the first speed reduction ratio at the maximum output state of the cylinder deactivation operation, in which nothing but a maximum until the vehicle speed V _2. In other words, the best engine driving force o'clock vehicle speed V ₂ of the six-cylinder operation when the second reduction ratio is lower than the highest of the engine driving force at the vehicle speed V ₃ of the cylinder deactivation operation when the first reduction ratio The second reduction ratio is set so that

Next, the second transmission path will be described. The motor 8 driven by being supplied with electric power from the generator 4 or the battery 20 via the inverter 21 has its motor shaft 8 a directly connected to the main gear 11.
The second transmission path includes a main gear 11, an output gear 12 meshing with the main gear 11, a pinion gear 13 driven coaxially with the output gear 12, a final gear 14 meshing with the pinion gear 13, and the final gear 14 Is provided with a differential gear 7 for driving the drive wheels 6. The driving force of the motor 8 is transmitted to the drive wheels 6 through this second transmission path.
The second transmission path is a fixed reduction ratio determined by the product of the gear ratio between the main gear 11 and the output gear 12 and the gear ratio between the pinion gear 13 and the final gear 14, and has a variable gear ratio. Does not have equipment.

As shown in FIG. 3, a hybrid ECU 23B is provided for controlling the operating state of the hybrid vehicle 50B. The hybrid ECU 23B controls the actuators 33B that individually control the clutch 5B and the clutch plate brake 5C to be turned on and off in response to the accelerator pedal depression amount and the brake pedal depression amount based on the vehicle speed signal. The hybrid ECU 23B has the same configuration as that of the first embodiment except for the above points, and is connected to the battery 20, the inverter 21 and the engine ECU 25 through communication lines in the same manner as the hybrid ECU 23A in the first embodiment. Signals similar to those in the first embodiment are exchanged and controlled.
The engine 1 is provided with an output characteristic variable mechanism 31 as in the first embodiment.
The same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

(Transmission path switching and shift control)
In the above configuration, the hybrid ECU 23B switches between the first transmission path and the second transmission path according to the vehicle speed as described below, and switches the reduction ratio of the first transmission path to change the hybrid vehicle 50B. Let it run.
FIG. 4 is a combination diagram of operating states of the clutch 5B and the clutch plate brake 5C in the traveling state of the hybrid vehicle 50B.
In the driving force characteristic diagram shown in FIG. 2, in the low vehicle speed range including the start time from the vehicle speed 0 to less than the vehicle speed V ₁ (second vehicle speed), when traveling uphill, etc., the hybrid ECU 23B uses the actuator 33B in FIG. As shown in the figure, the clutch 5B and the clutch plate brake 5C are turned off to enter the series operation (motor drive) mode. As can be seen from FIG. 3, when both the clutch 5B and the clutch plate brake 5C are off (OFF), the difference in the number of teeth between the ring gear 18 and the pinion gear 16 regardless of whether the planetary carrier 17 is stopped or rotating. Since the sun gear 15 idles and absorbs, the output shaft 2 and the ring gear 18 are separated. In this way, the engine 1 is disconnected from the first transmission path, and the hybrid ECU 23B controls the inverter 21, drives the motor 8, and drives the generator 4 as necessary to generate power. The driving force of the motor 8 is transmitted to the driving wheel 6. In this way, at the start of a low vehicle speed or at a low vehicle speed, the hybrid vehicle 50B is driven by performing a motor operation with a high driving force.

Next, when the vehicle speed becomes a steady running state equal to or higher than the vehicle speed V ₁ (second vehicle speed), the inverter 21 is controlled to stop the driving of the motor 8, and the hybrid ECU 23B is shown by the characteristic curve a. The vehicle is driven in the state of the second reduction ratio, which has better fuel efficiency than the six-cylinder operation directly connected to the engine 1. That is, as shown in FIG. 4, the actuator 33B turns off the clutch 5B, turns on the clutch plate brake 5C, and accelerates the rotation of the output shaft 2 in the planetary gear 10 to the output gear 12. Communicate (engine drive by speed increase stage). The drive characteristic of the maximum output of the engine 1 at this time is shown by a characteristic curve e in FIG. 2, and a necessary driving force can be obtained without stepping on the accelerator. However, in the planetary gear 10 is the overdrive speed state, in the state where the speed reduction ratio of the reduction gear 9B is a second reduction ratio, not put out only up to a maximum of the vehicle speed V _2, as shown in FIG. 2, the vehicle speed V ₂ driving force is less than the driving force when the highest vehicle speed V ₃ at the maximum output of the engine 1 of the cylinder deactivation operation state in the directly coupled state of the engine 1 in.
When the clutch 5B and the clutch plate brake 5C are in such a state and the engine output is sufficient, the engine ECU 25 causes the engine 1 to perform a cylinder deactivation operation as necessary.

Further, if the vehicle speed from Ueno is greater from the vehicle speed _{V 2} vicinity shown in FIG. 2, the hybrid ECU23B is by the actuator 33B is turned on (ON) the clutch 5B as shown in FIG. 4, the clutch plate brake 5C off ( OFF) so that the sun gear 15 and the planetary carrier 17 rotate together (engine direct drive). If the driving force may be small and the accelerator pedal depression amount is small, for example, on a flat ground, the engine ECU 25 determines that the required torque is small, and the engine ECU 25 causes the engine 1 to perform a low output operation by cylinder deactivation. The engine low output operation is performed due to the suspension, and the rotation of the output shaft 2 is transmitted to the output gear 12 in a directly connected state without being accelerated by the planetary gear 10.
When accelerating and decelerating in the medium / high speed range, the motor 8 performs assist drive or regenerative power generation as in the first embodiment.

Furthermore, in the range from the vehicle speed _{V 4} or more to a maximum speed _{V max,} the hybrid ECU23B performs the same control as in the first embodiment. That is, the mode is a parallel operation mode in which the motor 8 assists the engine drive.

(Effect of the second embodiment)
As described above, according to the hybrid vehicle 50B of the second embodiment, even in the low speed range of the vehicle speed 0 to less than the vehicle speed V _1, when there is a great need driving force, the clutch 5B and the clutch plate brake 5C The drive wheels 6 are driven only by the motor 8 (series operation). In the medium / high vehicle speed range (second vehicle speed range) from the vehicle speed V ₁ (second vehicle speed) not including the maximum speed V _max to less than the vehicle speed V ₄ (first vehicle speed), in principle, in a steady driving state The drive wheels 6 are driven only by the engine 1, and the motor 8 assists when accelerating as necessary. In the range of the maximum vehicle speed (first vehicle speed range) equal to or higher than the vehicle speed V ₄ (first vehicle speed) including the maximum speed V _max , the drive wheels 6 are driven by both driving of the engine 1 and driving of the motor 8 (parallel). Driving mode).

In this way, the range of the high-speed in not including the maximum velocity V _max and steady running only by the engine 1, corresponding to the first maximum velocity V _max lower vehicle speed V ₄ the reduction ratio of the _(first vehicle speed) Let me set. Therefore, as shown in FIG. 2, the characteristic curve a in the present embodiment is such that the maximum speed V _max of the hybrid vehicle 50B can be achieved only by the driving force of the conventional engine 1 described in Patent Document 1. The driving force is smaller than the characteristic curve f of the driving force of the engine 1 when the transmission path reduction ratio is set, and the engine is operated at a lower rotation and a higher load with respect to the same running resistance. Fuel consumption is improved. Further, in the case of flat ground traveling or the like where the driving force may be small, traveling can be performed with the driving characteristics in the cylinder deactivation operation as shown by the characteristic curve d, and steady traveling with better fuel consumption can be performed.
In particular, in the combination of engine driving and motor driving in a hybrid vehicle 50B equipped with a large displacement engine as the engine 1, the marginal driving force is large because it is a large displacement engine, but the first reduction ratio of the reduction gear 9B is large. (Gear ratio) is set to a higher ratio gear ratio than the conventional hybrid vehicle, and fuel efficiency is remarkably improved as compared with the conventional hybrid vehicle. Further, in the case of a combination with such a large displacement engine, it is possible to improve fuel efficiency by combining a large displacement multi-cylinder engine with an output characteristic variable mechanism 31 including a cylinder deactivation function.

Further, the vehicle speed V that can be achieved at the maximum output by the first reduction ratio when the second reduction ratio is a reduction ratio smaller than the first reduction ratio and the output characteristic variable mechanism 31 reduces the output. _The vehicle speed V ₂ is set to be lower than ₃ . That is, by driving force when the vehicle speed V ₂ is to allow shifting to the second speed reduction ratio becomes smaller driving force, it can be made more fuel efficient engine rotational speed is slow steady running state.

In this embodiment, in the range up to the vehicle speed V ₄ or the maximum speed V _max, the motor 8 as described above, instead of the assist operation of the engine driving, is separated first transmission path of the engine 1, the engine 1 may be a series operation in which the generator 4 is driven to generate electric power and the motor 8 is driven by the electric power.
In the present embodiment, the motor shaft 8a is directly connected to the main gear 11. However, as in the first embodiment, the driving force is applied to the main gear 11 via the output gear provided on the motor shaft 8a. You may make it tell.

Further, in the first embodiment and the second embodiment, the maximum vehicle speed range (first vehicle speed range) and the vehicle speed V ₄ or more, is not limited to the vehicle speed V ₄ or more. Even if the middle / high vehicle speed range (second vehicle speed range) is set to a vehicle speed value lower than the vehicle speed V ₄ where the combustion efficiency of the engine 1 is good, and the vehicle speed value switched to the assist drive by the motor 8 or the series operation is further reduced. good.

(Modification of the first and second embodiments)
In the first and second embodiments, the motor driving force of the motor 8 is transmitted to the main gear 11 via the input gear 8b provided on the motor shaft 8a, or the main gear 11 The motor shaft 8a is directly connected to the transmission. Then, driving by the motor 8 are intended to cover the vehicle speed range from the vehicle speed 0 to less than the vehicle speed V _1, the vehicle speed range from the vehicle speed V ₄ to a maximum velocity V _max. Incidentally, in a vehicle speed range from the vehicle speed _{V 4} to a maximum velocity _{V max} is the rotational speed of the motor 8 may exceed 10,000 rpm.
Although it is easy to control the inverter 21 so that the motor 8 rotates at a higher speed, the mechanical structure such as the rotor and the bearing of the motor 8 becomes stricter and the strength of the motor 8 is increased. Therefore, the weight may increase. Therefore, as a modification in the first and second embodiments, the rotational speed of the motor shaft 8a can be made "directly connected" or "accelerated" by the two-stage transmission, and the output shaft of the two-stage transmission can be changed. You may make it transmit rotation to the main gear 11 via a gear. Then, the transmission speed of the two-stage transmission is selected by the hybrid ECU23A or hybrid ECU23B, "direct connection" in the range from the vehicle speed 0 to less than the vehicle speed _{V 1,} the vehicle speed _{V 4} to a maximum velocity _{V max} by a "speed increase", it is possible to operate by lowering the rotational speed of the motor 8 in the vehicle speed range from the vehicle speed V ₄ to a maximum velocity V _max.

1 is a schematic schematic view of an entire hybrid vehicle according to a first embodiment of the present invention. It is a driving force characteristic figure of the hybrid vehicle of a 1st embodiment. It is a schematic diagram of the whole hybrid vehicle of the 2nd Embodiment of this invention. FIG. 10 is a combination diagram for explaining operations of a clutch and a clutch plate brake that perform switching and shifting for transmitting engine driving force of the hybrid vehicle of the second embodiment to driving wheels through a first transmission path.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 1a Cylinder 2 Output shaft 4 Generator 5A, 5B Clutch 5C Clutch plate brake 6 Drive wheel 8 Motor 8a Motor shaft 8b Input gear 9A, 9B Reducer 10 Planetary gear (transmission gear)
11 Main Gear 12 Output Gear 13 Pinion Gear 14 Final Gear 15 Sun Gear 16 Pinion Gear 17 Planetary Carrier 18 Ring Gear 20 Battery 21 Inverter 23A, 23B Hybrid ECU
25 Engine ECU
31 Output characteristic variable mechanism 33A, 33B Actuator 50A, 50B Hybrid vehicle

Claims (6)

A first transmission path for transmitting the engine driving force of the engine to the driving wheels and a second transmission path for transmitting the motor driving force of the motor to the driving wheels, which are alternatively selected or used in combination. A hybrid vehicle that travels,
The hybrid vehicle according to claim 1, wherein the first speed reduction ratio of the first transmission path is set smaller than a speed reduction ratio in a case where a maximum speed achievable by the vehicle is obtained only by an engine driving force.   When the vehicle achieves the maximum speed, only the motor driving force is transmitted to the driving wheel through the second transmission path, or the motor driving force is transmitted to the driving wheel through the second transmission path. The hybrid vehicle according to claim 1, wherein the engine driving force is transmitted to the driving wheels through the first transmission path. The engine has an output characteristic variable mechanism that varies an output characteristic,
The first transmission path has a reduction ratio smaller than the first reduction ratio, and the output of the engine is reduced by the first reduction ratio when the output characteristic is reduced by the output characteristic variable mechanism. 3. The hybrid vehicle according to claim 1, further comprising a transmission gear capable of setting a second reduction ratio that is a driving force that is smaller than a driving force that can be achieved at the time of maximum output in a state of being in a closed state.   The hybrid vehicle according to claim 3, wherein the output characteristic variable mechanism performs a cylinder deactivation operation of deactivating some cylinders during operation of the engine.   The hybrid vehicle according to claim 3, wherein the output characteristic variable mechanism performs at least one of valve opening / closing control, ignition timing timing control, and fuel injection control. A first transmission path for transmitting the engine driving force of the engine to the driving wheels and a second transmission path for transmitting the motor driving force of the motor to the driving wheels, which are alternatively selected or used together A hybrid vehicle that travels,
The first speed reduction ratio of the first transmission path is set smaller than the speed reduction ratio in the case where the maximum speed that can be achieved by the vehicle is obtained only by the engine driving force,
The first transmission path and the second transmission path include a common output gear that transmits at least one of the engine driving force and the motor driving force to the driving wheels.
In a first vehicle speed range including a first vehicle speed or higher that does not include a stop state of the vehicle and a maximum speed that can be achieved by the vehicle, at least the motor driving force is transmitted to the driving wheels through the second transmission path;
In a second vehicle speed range from a second vehicle speed that is lower than the first vehicle speed to less than the first vehicle speed, the engine driving force is transmitted to the drive wheels through the first transmission path during steady running. A featured hybrid vehicle.

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