JPH11275710A - Hybrid driving system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily secure maximum speed and driving force required by a vehicle, without having to change the output characteristics of an electric motor or to use a transmission. SOLUTION: This hybrid driving system is provided with an auxiliary power transmitting mechanism 23, which selectively connects a generator 3 to an engine 1 or a driving system device 13 of a vehicle, a means 19 for detecting the speed of a vehicle, a means 20 for detecting driving force demanded by the vehicle, and a means 18 for controlling the converter 4 of the generator 3 and auxiliary power transmitting mechanism 23, in such a way as to let the generator 3 work as an electric motor when the demanded driving force of the vehicle is equal to or larger than the maximum torque of electric motors 5, 6 in the low-speed range of a specified value or lower, at which the vehicle speed is made to shift to a constant output range of the electric motors 5, 6, based on these detected signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an improvement in a hybrid drive system for a vehicle.

[0002]

2. Description of the Related Art In order to improve vehicle exhaust emissions, a hybrid drive system combining an engine and an electric motor drives only a generator with an engine,
There is known a type in which the generated power is used for charging a battery and driving an electric motor, and a driving force of a vehicle depends only on an output of the electric motor.

[0003]

In such a hybrid drive system, the rotational speed range in which the motor can be operated at a constant output is limited, so that the maximum driving force and the maximum speed required for the vehicle are reduced unless a transmission is used. There was a problem that it was difficult to achieve both. Japanese Patent Application Laid-Open No. 9-154204 discloses a configuration in which a generator is driven when the output of an electric motor is insufficient for a required driving force of a vehicle even in a state where the charge rate of a battery is sufficiently high. However, even if the electric power from the generator is added to the electric power from the battery to the electric motor, a driving force exceeding the output performance (maximum torque) of the electric motor cannot be obtained.

The present invention has been made in view of such problems, and can secure the maximum speed and the maximum driving force required for the vehicle without changing the output characteristics of the electric motor and without using a transmission. The purpose is to provide a hybrid drive system.

[0005]

According to a first aspect of the present invention, an engine that drives a generator, a battery that is charged by the generator via a converter, and a battery and the generator that are driven by an inverter through an inverter. In a vehicle including an electric motor for driving the vehicle and a drive system for transmitting an output of the electric motor to wheels, an auxiliary power transmission mechanism for selectively connecting a generator to an engine and a drive system of the vehicle, and a vehicle speed. Means for detecting the required driving force of the vehicle, and a means for detecting the required driving force of the motor in a low-speed region where the vehicle speed shifts to a constant output region of the motor based on these detection signals. Means for controlling the converter of the generator and the transmission mechanism of the auxiliary power so that the generator operates as a motor when the torque is equal to or more than the torque.

According to a second aspect of the present invention, there is provided an engine for driving a generator, a battery charged by the generator via a converter, and a motor for driving a vehicle driven by an inverter using the battery and the generator as a power source. A drive system for transmitting the output of the motor to the wheels, in a vehicle, an auxiliary power transmission mechanism for selectively connecting the engine to the generator and the drive system of the vehicle, and a means for detecting vehicle speed, Means for detecting a required driving force of the vehicle, and an engine when the required driving force of the vehicle is equal to or greater than the maximum torque of the electric motor in a low-speed region where the vehicle speed shifts to a constant output region of the electric motor based on the detection signals and is equal to or less than a predetermined value. Means for controlling a transmission mechanism of the auxiliary power so as to transmit the output of the vehicle to the drive system device of the vehicle.

In the third invention, the auxiliary power transmission mechanism according to the first invention or the second invention has a reverse rotation mechanism.

[0008] In a fourth aspect, the auxiliary power transmission mechanism according to the first or second aspect includes a continuously variable transmission.

[0009]

According to the first aspect of the present invention, the output of the electric motor is transmitted to the wheels (drive wheels) via the drive system (forming the power transmission path). In a low speed region where the vehicle speed is equal to or lower than a predetermined value, when the required driving force of the vehicle exceeds the maximum torque of the electric motor, the converter and the auxiliary power transmission mechanism are controlled so that the generator operates as the electric motor. As a result, the output of the generator is transmitted to the drive system and added to the output of the motor as the driving force of the vehicle, so that a driving force exceeding the maximum torque of the motor is obtained. As a result, while the total reduction ratio of the drive train is set so that the maximum speed required for the vehicle can be obtained as before, the output characteristics of the motor are changed by operating the generator as a motor as described above. The required maximum driving force can be secured without using a transmission.

In the second invention, the output of the electric motor is transmitted to wheels (drive wheels) via a drive system device (which constitutes a power transmission path). In a low-speed region where the vehicle speed is equal to or lower than a predetermined value, when the required driving force of the vehicle exceeds the maximum torque of the electric motor, the transmission mechanism of the auxiliary power is controlled so as to transmit the output of the engine to the driving system. As a result, the output of the engine is added to the output of the motor as the driving force of the vehicle, so that a driving force exceeding the maximum torque of the motor can be obtained.
As a result, while the total reduction ratio of the drive train is set so that the maximum speed required for the vehicle can be obtained as before, the output characteristics of the motor are changed by operating the generator as a motor as described above. The required maximum driving force can be secured without using a transmission.

In the third aspect, a driving force exceeding the maximum torque of the electric motor can be obtained not only when the vehicle moves forward but also when the vehicle moves backward.

According to the fourth aspect of the present invention, it is possible to operate the generator or the engine near the best point of the energy efficiency through the continuously variable transmission when transmitting the auxiliary power.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 denotes an engine for power generation, and a drive shaft of a generator 3 is connected to an output shaft of the engine via a gearbox 2. The AC power generated by the generator 3 is converted to DC power via the converter 4 and
1 (battery) and for driving the electric motors 5 and 6.

Reference numeral 7 denotes an axle of a driving wheel 8;
A differential 9 is interposed in the intermediate portion. Propeller shaft 1 on drive pinion of differential 9
0, the output shaft of the reduction gear 11 is connected.

The speed reducer 11 is provided with two input shafts sandwiching one output shaft, and electric motors 5 and 6 are connected to these two input shafts. Then, gears 11a and 11b meshing with the same gear ratio between each input shaft and output shaft are interposed.

The electric motors 5 and 6 are driven when receiving AC power from the inverter 12. The output is transmitted to wheels 8 via a reduction gear 11, a propeller shaft 10, a differential 9, and an axle 7. In other words, the reduction gear 11, the propeller shaft 10, the differential 9, and the axle 7 drive the drive system device 13 for transmitting the output of the electric motors 5, 6 to the wheels 8.
(Power transmission mechanism).

The gearbox 2 has a gear 2 meshing between an input shaft on the engine 1 side and an output shaft on the generator 3 side at a predetermined gear ratio.
a, 2b, and one end of an auxiliary propeller shaft 14 is connected to an input shaft of the auxiliary propeller shaft 14 to constitute an auxiliary power transmission mechanism 23. Also, the input shaft gear 2a
The other end of the auxiliary propeller shaft 14 is connected to one input shaft of the speed reducer 11 via bevel gears 17a and 17b.

A controller 18 for controlling the clutches 15 and 16 and the converter 4 of the generator 3 together with the inverter 12 of the electric motors 5 and 6 is provided, a vehicle speed sensor 19 for detecting a running speed (vehicle speed) of the vehicle, and an accelerator pedal depression. An accelerator opening sensor 20 for detecting the amount and a battery 2
And a means (not shown) for detecting the state of charge of the battery.

The converter 4 converts the AC power generated by the generator 3 into a battery 2 according to a signal from the controller 18.
1 and an electric mode in which the DC power of the battery 21 is converted into AC power to the generator 3.

In response to a signal from the controller 18, the clutches 15, 16 do not transmit the output of the engine 1 to the auxiliary propeller shaft 14 in the power generation mode of the converter 4, but input the power to the generator 3 via the gearbox 2, while Converter 4
In the electric mode, the generator 3 is disconnected from the engine 1,
The output of the generator 3 operated as a motor is controlled to be transmitted to the auxiliary propeller shaft 14.

In FIG. 2, A is the maximum output line that the battery 21 can provide, B is the maximum output line of the motors 5 and 6, and the motors 5 and 6 have a predetermined vehicle speed based on their capacity (maximum torque). In the low-speed range below the value P, the operation is controlled to the constant torque operation. Further, in the constant output region of the electric motors 5 and 6 (middle and high speed region where the vehicle speed exceeds a predetermined value), when only the battery 21 is driven by the power supply, the driving force along the maximum output line A of the battery 21 is generated. When the battery 21 and the generator 3 are driven by a power supply, the driving force is set to be increased by an increase in the power of the generator 3 (a hatched area C rising to the right).

FIG. 3 is a flowchart for explaining the control contents of the controller 18, which is started by turning on a key switch. In step 1, the operating regions of the electric motors 5, 6 are determined based on the detection signal of the vehicle speed sensor 19. If it is in the constant output range, the process jumps to step 6 where the clutch 15 is turned on (connected) and the clutch 16 is turned off (disconnected), while the converter 4 is switched to the power generation mode.

The output of the engine 1 is input to the generator 3 via the clutch 15 and the gearbox 2, and is not transmitted to the auxiliary propeller shaft 14. The AC power generated by the generator 3 is converted into DC power via the converter 4.

In step 7, based on the detection signal of the vehicle speed sensor 19 and the detection signal of the accelerator opening sensor 20,
The required power of the motors 5 and 6 (determined by the product of the vehicle speed and the accelerator opening) is calculated. If the calculated value is equal to or less than the maximum output line A of the battery 21 (see FIG. 2), step 8
In step 9, the generator 12 is driven by the engine 1 according to the state of charge of the battery 21. On the other hand, in step 9, the inverter 12 is controlled so that the motors 5 and 6 are operated only by the battery 21. The generated electric energy is charged in the battery 21.

When the required power of the motors 5 and 6 exceeds the maximum output line A of the battery 21, the process jumps from step 7 to step 10 to drive the generator 3 with the engine 1 and to use the motor 5 at step 11 with the insufficient power. , 6 are operated within a range not exceeding the maximum output line B (see FIG. 2).

When the motors 5 and 6 are in the constant torque range, the process proceeds from step 1 to step 2 in which only the battery 21 is used as a power source. Then, in step 3, the required driving force (accelerator opening) is obtained from the detection signal of the accelerator opening sensor 20.
Is determined.

When the required driving force is equal to or less than the maximum torque of the electric motors 5 and 6, the process jumps from step 3 to step 8 in which the engine 1 is driven by the engine 1 in accordance with the state of charge of the battery 21. Electric motor 5, only 21
The inverter 12 is controlled so as to operate the inverter 6.

When the required driving force exceeds the maximum torque of the motors 5 and 6, the converter 15 is turned off and the clutch 16 is turned on in step 4, while the converter 4 is operated so that the generator 3 is operated as a motor in step 5. Is switched to the electric mode. The generator 3 is driven by the battery 21 as a power source, and outputs the gears 2a and 2b, the clutch 16,
The power is transmitted to the reduction gear 11 of the drive system device 13 via the auxiliary propeller shaft 14 and the bevel gears 17a and 17b.

With such a configuration, in a low speed region where the vehicle speed is equal to or lower than a predetermined value, the required driving force of the vehicle is reduced by the electric motor 5,
When the torque exceeds the maximum torque of 6, the generator 3 is operated as a motor, and its output is added to the output of the motors 5 and 6, so that a driving force exceeding the maximum torque of the motors 5 and 6 is obtained.

2 indicates the increase in the driving force due to the auxiliary power of the generator 3. Since the generator 3 is driven by the electric energy of the battery 21, the maximum driving force does not exceed the maximum output line A of the battery 21.

The total reduction ratio of the drive train 13 is set so that the maximum speed required for the vehicle can be obtained as before,
As described above, when the auxiliary power from the generator 3 to the drive system device 13 is obtained, the required maximum driving force can be easily increased without changing the output characteristics of the motors 5 and 6 and without using a transmission. Can be secured.

In the embodiment of FIG. 4, the auxiliary power transmission mechanism 23 is provided so that the driving power exceeding the maximum torque of the electric motors 5 and 6 can be obtained by the auxiliary power of the generator 3 not only when the vehicle is moving forward but also when the vehicle is moving backward. A reversing mechanism 25 is provided at (between the auxiliary propeller shaft 14 and the gearbox 11).

As the reverse rotation mechanism 25, the same one as a known mechanism for switching to reverse of a transmission is employed. Although detailed description is omitted, the input rotation can be transmitted as it is, as well as transmitted in the reverse direction, by selectively displacing the sliding gear with the dog clutch by the actuator.

Although not shown, if a continuously variable transmission (for example, a CVT or a torque converter) is interposed in series with the reversing mechanism, the generator 3 can be operated as a motor near the best point of energy efficiency. The same parts as those in FIG. 1 are denoted by the same reference numerals.

In FIG. 1, when the generator 3 is operated as an electric motor, the engine 1 is operated and both clutches 1 are operated.
When the switches 5 and 16 are turned on, the output of the engine 1 can be transmitted to the drive system device 13 as auxiliary power. Further, when a clutch for intermittently connecting between the generator 3 and the gearbox 2 is added, the case where only the output of the generator 3 is transmitted, the case where only the output of the engine 1 is transmitted, and the output of the generator 3 It is also possible to control the auxiliary power in three stages, that is, when both the output of the engine 1 is transmitted.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an embodiment of the present invention.

FIG. 2 is a characteristic diagram for explaining control contents.

FIG. 3 is a flowchart for explaining control contents.

FIG. 4 is a main part configuration diagram showing another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 3 Generator 4 Converter 5, 6 Electric motor 12 Inverter 13 Drive system device (power transmission mechanism) 14 Auxiliary propeller shaft 15, 16 Clutch 17a, 17b Bevel gear 18 Controller 19 Vehicle speed sensor 20 Accelerator opening sensor 21 Battery 23 Auxiliary power Transmission mechanism 25 reverse rotation mechanism

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // F16H 59:18 59:44

Claims (4)

[Claims] An engine for driving a generator, a battery charged by the generator via a converter, a motor for driving a vehicle driven by an inverter using the battery and the generator as a power source, and an output of the motor A transmission system for transmitting power to wheels, an auxiliary power transmission mechanism for selectively connecting a generator to the engine and the vehicle driving system, a means for detecting vehicle speed, and a required drive of the vehicle. Means for detecting the force, and the generator as the motor when the required driving force of the vehicle is equal to or more than the maximum torque of the motor in a low speed region below a predetermined value where the vehicle speed shifts to a constant output region of the motor based on these detection signals. Means for controlling the converter of the generator and the transmission mechanism of the auxiliary power to operate the hybrid drive system. 2. An engine for driving a generator, a battery charged by the generator via a converter, a motor for driving a vehicle driven by an inverter using the battery and the generator as a power source, and an output of the motor. A transmission system for transmitting power to wheels, an auxiliary power transmission mechanism for selectively coupling an engine to a generator and a vehicle driving system, a means for detecting a vehicle speed, and a required drive of the vehicle. Means for detecting the force, and outputting the engine output when the required driving force of the vehicle is equal to or greater than the maximum torque of the motor in a low-speed region where the vehicle speed shifts to a constant output region of the motor based on the detection signals. Means for controlling an auxiliary power transmission mechanism so as to transmit the power to the drive system device. 3. The hybrid drive system according to claim 1, wherein the auxiliary power transmission mechanism includes a reverse rotation mechanism. 4. The hybrid drive system according to claim 1, wherein the auxiliary power transmission mechanism includes a continuously variable transmission.