JP2003212003A - Hybrid vehicle control device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide an engine start in a wide vehicle speed range including an extremely low speed range without providing a separate start motor, and to stop the vehicle due to an engine stall or unexpectedly lower the driving force. And other inconveniences. An output shaft (4a) of a motor (4) is connected to an input shaft (5a) of a transmission (5), and an output shaft (3a) of an engine (3) and an input shaft (5a) of the transmission (5) are connected via a first clutch (8). 5 is a control device for the hybrid vehicle 2 in which the input shaft 5a of the vehicle 5 and the driving wheel 6 are connected via the second clutch 9 and the driving wheel 6 is driven by the engine 3 and the motor 4. When starting the engine 3 from a driving state, the rotation speed of the input shaft 5a of the transmission 5
If the rotation speed is lower than the rotation speed required to start the vehicle, the control device for the hybrid vehicle 2 that controls the second clutch 9 to be in the half-clutch state and to connect the first clutch 8 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid vehicle control device using an engine and a motor as drive sources.

[0002]

2. Description of the Related Art A hybrid vehicle runs by stopping the engine in a light load range and driving a motor using a battery. The battery stores electric power generated during regeneration or when the engine is driven in a high load range. This can improve fuel efficiency.

In order to maximize the fuel consumption improving effect, it is desirable that the engine can be arbitrarily started in response to a high load request from the driver regardless of the running state of the vehicle. That is, for example, it is desirable that the engine can be immediately started in response to a high load request from the driver due to depression of the accelerator pedal not only during high-speed traveling by the motor but also during low-speed traveling by the motor.

Conventionally, in order to meet the above-mentioned demand, a method has been adopted in which a small motor for starting the engine is provided separately from the motor for traveling. According to this method, the engine can be started by the operation of the small motor regardless of the traveling state, that is, without changing the operating state of the traveling motor.

However, the motor is very expensive, and the addition of the small motor which operates only for starting the engine in this manner increases the product cost, which is not desirable. Therefore, for example, Japanese Patent Laid-Open No. Sho 6
As disclosed in Japanese Patent Application Laid-Open No. 0-55803, a method has been devised for starting the engine by using the rotational force of the traveling motor or the axle while traveling by the traveling motor.

According to this method, the first clutch is arranged between the output shaft of the motor and the crankshaft of the engine, while the second clutch is arranged between the output shaft of the motor and the axle. This is a method of transmitting the rotational force of the motor or the axle to the crankshaft of the engine to completely start the engine while the vehicle is traveling only by the motor in which only the second clutch is completely engaged and the first clutch is completely engaged. According to this, since the traveling motor is used for starting the engine, it is not necessary to install a separate motor, and the cost increase can be further reduced.

[0007]

However, the above-mentioned conventional method has the following problems. That is,
In the conventional method of completely engaging the first clutch between the output shaft of the motor and the crankshaft of the engine, the rotation speed of the crankshaft of the engine is uniquely defined with respect to the rotation speeds of the output shaft of the motor and the axle. To be done. As a result, in the low vehicle speed range, the output shaft of the motor or the rotation speed of the axle is low,
Even if the first clutch is engaged, there is a problem in that the rotation speed of the crankshaft required to start the engine cannot be obtained.

Therefore, in such a low vehicle speed range, when the remaining capacity of the battery is reduced or when a rapid acceleration request is made, a sufficient negative pressure cannot be obtained even if the engine is started, and the engine is not started. It is considered that the inconvenience may occur, such as being stalled and stopping. In the above-mentioned conventional method, in order to avoid the engine stall condition, the second clutch is disengaged to separate the engine from the axle to bring the engine into a free running state, and the engine speed is increased to start the engine. Is also possible. However, in the case of such a method, for example, when traveling on an uphill, there is a possibility that necessary driving force cannot be obtained.

The present invention has been made in view of the above-mentioned circumstances, and does not include a separate starting motor,
Control of a hybrid vehicle that can arbitrarily start the engine in a wide range of vehicle speeds including the extremely low speed range, and can prevent inconveniences such as vehicle stop due to engine stall and unexpected reduction in driving force The purpose is to provide a device.

[0010]

In order to achieve the above object, the present invention proposes the following means. Claim 1
According to the invention, the output shaft of the motor is connected to the input shaft of the transmission, the output shaft of the engine and the input shaft of the transmission are connected via the first clutch, and the input shaft of the transmission and the drive wheels are connected. A control device for a hybrid vehicle, in which a drive wheel is driven by an engine and a motor, which are connected via a second clutch, and which is used as an input shaft of a transmission when starting the engine from a state in which the drive wheel is driven by the motor. Has proposed a control device for a hybrid vehicle that controls to engage the first clutch while keeping the second clutch in the half-clutch state when the number of revolutions is lower than the speed required to start the engine. .

According to the control apparatus for a hybrid vehicle of the present invention, when the drive wheels are driven by the motor, the second clutch is engaged and the rotational force from the motor is transmitted to the drive wheels via the transmission. In this state, when a high load request that is not satisfied only by the motor is made, such as a sudden acceleration request, it is required to start the engine. In that case, the input shaft of the transmission is required. It is determined whether or not the rotation speed of is lower than the rotation speed required to start the engine.

As a result of the judgment, when the rotation speed of the input shaft of the transmission is higher than the rotation speed required to start the engine, the rotational force of the input shaft of the transmission is changed by connecting the first clutch. To start the engine. When the rotation speed of the input shaft of the transmission is lower than the rotation speed required to start the engine, the second clutch is put in the half-clutch state. As a result, a part of the rotational force of the motor is transmitted to the drive wheels via the second clutch while maintaining the traveling state,
It is possible to increase the rotation speed of the motor and increase the rotation speed of the input shaft of the transmission separately from the rotation of the drive wheels.

In this state, by connecting the first clutch and connecting the output shaft of the engine and the input shaft of the transmission, the engine speed is higher than that required for starting the engine. The output shaft can be rotated. As a result, the engine is prevented from becoming stalled, and it becomes possible to achieve a smooth engine start and a quick response to a sudden acceleration request.

According to a second aspect of the present invention, the output shaft of the motor is connected to the input shaft of the transmission, the output shaft of the engine and the input shaft of the transmission are connected via the first clutch, and the input of the transmission is set. A control device for a hybrid vehicle in which a shaft and a drive wheel are connected via a second clutch, and the drive wheel is driven by an engine and a motor, when starting the engine from a state where the drive wheel is driven by the motor. When the rotation speed of the input shaft of the transmission is lower than the rotation speed required to start the engine, the second clutch is half-clutched only when the remaining capacity of the battery falls below a predetermined value. A control device for a hybrid vehicle that controls to engage the first clutch while maintaining the state is proposed.

According to the present invention, even when the rotation speed of the input shaft of the transmission is lower than the rotation speed required to start the engine, when the remaining capacity of the battery is sufficient, the engine Since the engine is not started, it is possible to continue traveling only by the motor and improve fuel efficiency. When the battery is low, start the engine. In this case, by starting the engine in the same manner as in claim 1, it is possible to start the engine without bringing it into a stalled state.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION A control device for a hybrid vehicle according to a first embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 2, the control device 1 according to the present embodiment includes an engine control unit ECU. Before describing the control device 1, a hybrid vehicle 2 to which the control device 1 is applied will be described. explain.

FIG. 1 is a schematic diagram showing an example of a hybrid vehicle 2 to which the control device 1 of the present invention is applied. This hybrid vehicle 2 is shown as having an engine 3, a motor 4, a transmission 5 and drive wheels 6.

The output shaft 4a of the motor 4 is connected to the input shaft 5a of the transmission 5 via a gear train 7, for example. The output shaft 3a of the engine 3 is connected to the input shaft 5a of the transmission 5 via the first clutch 8. The output shaft 5b of the transmission 5 is connected to the drive wheels 6. Input shaft 5 of transmission 5
A second clutch 9 is arranged between a and the output shaft 5b of the transmission 5. The second clutch 9 is capable of selectively connecting or disconnecting each transmission gear 10 in the transmission 5 to the input shaft 5a of the transmission 5 so as to realize a gear ratio selected according to the vehicle speed. It has become. In FIG. 1, a 5-speed automatic transmission is illustrated as the transmission 5.

A rotation speed sensor 1 is attached to the output shaft 4a of the motor 4.
1 is attached. In addition, the output shaft 5b of the transmission 5
A vehicle speed sensor 12 is attached to the vehicle. As described above, the output shaft 4a of the motor 4 is the input shaft 5a of the transmission 5.
Further, since the gear train 7 is connected, the rotation speed sensor 11 detects the rotation speed of the output shaft 4a of the motor 4 as follows.
This is equivalent to detection of the rotation speed of the input shaft 5a of the transmission 5. Further, since the output shaft 5b of the transmission 5 is connected to the drive wheel 6 via the gear 13 and the differential gear 14, the rotation speed of the output shaft 5b of the transmission 5 is detected by the vehicle speed sensor 12 by the drive wheel. This is equivalent to the detection of the number of rotations of 6 and the detection of the vehicle speed.

As shown in FIG. 2, the control device 1 for the hybrid vehicle 2 according to the present embodiment has, as inputs, a battery remaining capacity signal, a rotation speed signal from the rotation sensor 11, and a vehicle speed signal from the vehicle speed sensor 12. , An accelerator opening signal, a shift position signal of the transmission 5, and the like. The output from the control device 1 includes a torque command signal for the motor 4,
A torque command signal for the engine 3, a hydraulic pressure command signal for the first clutch 8, a hydraulic pressure command signal for the second clutch 9, and the like are output.

A storage unit (not shown) is provided inside the control unit 1 and stores the number of rotations of the input shaft 5a of the transmission 5 necessary for starting the engine 3. The control device 1 for the hybrid vehicle 2 according to the present embodiment is configured to disconnect the first clutch 8 and connect the second clutch 9 when driving the drive wheels 6 only by the motor 4. At this time, the hydraulic pressure command signal supplied to the second clutch 9 is a signal for generating a hydraulic pressure that completely connects the second clutch 9. As a result, the rotational force of the motor 4 is transmitted to the drive wheels 6 via the first clutch 8 and the transmission 5.

Further, when the engine 3 is started from the traveling state of only the motor 4 described above, the rotation speed of the input shaft 5a of the transmission 5 is calculated from the rotation speed signal received from the rotation sensor 11, and the transmission 5 If the number of revolutions of the input shaft 5a is higher than the number of revolutions required to start the engine 3 stored in the storage unit, the first clutch 8
Is configured to connect. At this time, the hydraulic pressure command signal supplied to the first clutch 8 is a signal for generating a hydraulic pressure that completely connects the first clutch 8. This allows
The rotational force of the motor 4 or the rotational force transmitted from the drive wheels 6 via the transmission 5 is transmitted to the output shaft 3a of the engine 3 via the second clutch 9 and the first clutch 8. Then, in accordance with this, the engine 3 is started by outputting a torque command to the engine 3.

On the other hand, the control device 1 according to the present embodiment uses the second clutch 9 when the rotation speed of the input shaft 5a of the transmission 5 is lower than the rotation speed required to start the engine 3. Is controlled so as to connect the first clutch 8 while keeping the half-clutch state. That is, the hydraulic pressure command signal supplied to the second clutch 9 is
Is a signal for generating a hydraulic pressure lower than the hydraulic pressure for completely connecting the second clutch 9 that has received this hydraulic pressure command signal.
Slides between the input shaft 5a of the transmission 5 and the transmission gear 10 so that a part of the rotational force of the motor 4 is transmitted.
It is possible to increase the number of rotations of the input shaft 5a of the transmission 5 while transmitting to 0.

When the rotation speed of the input shaft 5a of the transmission 5 exceeds the rotation speed required to start the engine 3, the first clutch 8 is completely connected to the first clutch 8. By supplying the hydraulic pressure, the rotational force of the input shaft 5a of the transmission 5 can be transmitted to the output shaft 3a of the engine 3 and the engine 3 can be started.

In this case, the transmission of the rotational force from the motor 4 to the drive wheels 6 via the transmission 5 is not completely lost, so that
It is possible to prevent the occurrence of so-called torque loss, and it is possible to avoid the occurrence of inconveniences such as a decrease in driving force during traveling on an uphill. And the motor 4 for traveling
Since the engine 3 can be started by, there is no need to arrange a separate motor for starting the engine 3,
The cost can be reduced.

FIG. 3 is a flow chart for explaining the operation of the control device 1 of the hybrid vehicle 2 according to this embodiment described above. First, when a high load request from the driver such as an increase in the accelerator opening signal occurs, it is determined in step 1 whether or not the vehicle is running only with the motor 4. As a result, when the traveling state is not based on only the motor 4, the current traveling state is maintained (step 4).

If the vehicle is traveling only with the motor 4, it is determined in step 2 whether or not the high load request such as the accelerator opening signal can be covered by only the motor 4. . If the load demand is high enough to be covered by only the motor 4, the traveling state by only the motor 4 is continued in principle (step 4). However, in this case, it is determined whether or not the remaining capacity of the battery is sufficient (step 3).

When it is determined in step 2 that the high load demand from the driver is too large to be covered by the motor 4 alone, the rotation speed of the input shaft 5a of the transmission 5 starts the engine 3. Therefore, it is determined whether or not the number of revolutions is equal to or higher than the necessary number of revolutions (step 5). When the rotation speed of the input shaft 5a of the transmission 5 is equal to or higher than the rotation speed required to start the engine 3, the hydraulic pressure command signal for completely connecting the first clutch 8 is supplied to the first clutch 8. (Step 8). As a result, the engine 3 is started,
A transition is made to a traveling state by the engine 3 and the motor 4 or a traveling state by only the engine 3 (step 9).

When the rotation speed of the input shaft 5a of the transmission 5 is lower than the rotation speed required to start the engine 3,
A hydraulic pressure command signal for connecting the second clutch 9 to the half-clutch state is supplied to the second clutch 9 (step 6). Then, in this state, the motor torque command signal is increased, and the rotation speed of the input shaft 5a of the transmission 5 is increased (step 7).

In this way, when the number of revolutions of the input shaft 5a of the transmission 5 reaches the number of revolutions sufficient to start the engine 3, the first clutch 8 is completely connected to the first clutch 8. A hydraulic pressure command signal for connection is supplied (step 8). As a result, the engine 3 is started (step 9). Further, when it is determined in step 3 that the remaining capacity of the battery is not sufficient, the process proceeds to step 5 to start the engine 3.

As described above, according to the control device 1 for the hybrid vehicle 2 according to the present embodiment, the rotational speed of the input shaft 5a of the transmission 5 is necessary for starting the engine 3 when the vehicle is running only by the motor 4. It is possible to start the engine 3 even when the engine speed is lower than this value. In this case, since the engine 3 is started by the motor 4 used for traveling, the starting motor is unnecessary and the cost can be reduced. Further, since the rotational force from the motor 4 to the drive wheels 6 is not lost when the engine 3 is started, it is possible to prevent the occurrence of troubles due to torque loss.

Furthermore, since the engine 3 can be started even when the remaining capacity of the battery is not sufficient for traveling or rapid acceleration by the motor 4 alone, the remaining capacity of the battery is generated by the engine 3 or the like. It is possible to recover the capacity. Further, even in the low vehicle speed region, the engine 3 is surely started, so that it is possible to prevent a situation in which the vehicle cannot travel due to insufficient remaining capacity of the battery even though the fuel remains.

Next, a control device 1'for a hybrid vehicle 2 according to a second embodiment of the present invention will be described below with reference to FIG. The control device 1 ′ according to the present embodiment is
When a high load request is made by the driver, the transmission 5 is not immediately switched to the mode in which the engine 3 is started.
The engine 3 is started only when the number of revolutions of the input shaft 5a exceeds the number of revolutions required to start the engine 3, and when the number of revolutions is less than the number of revolutions, the remaining capacity of the battery is checked once. In the above, the control device 1 is different from the control device 1 according to the first embodiment.

That is, as shown in FIG. 4, step 2
In step S5, it is determined whether or not the driver's high load request can be covered by only the motor 4. Determines whether the engine speed is higher than that required to start the engine 3. If it is higher, go to step 8
The clutch 8 is completely engaged and the engine 3 is started. On the other hand, if it is below the range, the remaining capacity of the battery is confirmed (step 3).

If the remaining capacity of the battery is sufficient to satisfy the high load requirement, the vehicle continues to run with only the motor 4 (step 4). When the remaining capacity of the battery is not sufficient to satisfy the high load requirement, the process proceeds to step 5 ′, and similarly to the first embodiment, the input shaft 5a of the transmission 5 is used.
The engine 3 is started in a different form depending on the number of revolutions.

With this configuration, even if the high load request from the driver is too large to be covered by only the motor 4, the input shaft 5a of the transmission 5 can be provided.
When the number of revolutions of is lower than the number of revolutions required to start the engine 3, traveling by only the motor 4 is continued unless the remaining capacity of the battery becomes insufficient.
Maximum acceleration is performed only by the motor 4, and the battery can be effectively used to improve fuel efficiency. When the rotation speed of the input shaft 5a of the transmission 5 exceeds the rotation speed required to start the engine 3, the second clutch 9 is completely engaged and the first clutch 8 is engaged, whereby the engine 3 can be started. Therefore, it is possible to reduce the wear of the second clutch 9.

When the remaining capacity of the battery is insufficient, the rotation speed of the input shaft 5a of the transmission 5 becomes the engine 3
Even when the engine speed is lower than that required for starting the engine, the engine 3 can be reliably started by sliding the second clutch 9, and therefore the engine 3 can charge the battery. Therefore, it is possible to prevent a situation in which the vehicle cannot run due to a decrease in the remaining capacity of the battery while the fuel remains.

The control device 1 according to each of the above embodiments is
In 1 ′, the rotation speed of the input shaft 5a of the transmission 5 is the engine 3
It was judged whether the number of rotations required to start the engine was reached. The input shaft 5a of the transmission 5 is disposed inside the transmission 5, and it is difficult to directly detect the number of rotations thereof. Therefore, the rotation sensor 1 attached to the output shaft 4a of the motor 4
It was decided to calculate from the detection value of 1. Instead of this, it may be calculated based on the vehicle speed detected by the vehicle speed sensor 12 arranged on the output shaft 5b of the transmission 5. Of course, the rotation speed of the input shaft 5a of the transmission 5 may be directly detected.

Further, instead of determining whether or not the engine 3 can be started based on the number of revolutions of the input shaft 5a of the transmission 5, a plurality of vehicle speeds at which the engine 3 can be started are stored in correspondence with the shift position. Alternatively, it may be determined whether or not the actual vehicle speed is a vehicle speed at which the engine 3 can be started.

Although the hydraulic pressure command signal supplied to the second clutch 9 is switched in two steps according to the number of revolutions of the input shaft 5a of the transmission 5, instead of this, three or more steps or no step. It may be changed to. As a result, when the engine 3 is started, the sudden acceleration / deceleration feeling given to the driver can be alleviated and the engine 3 can be started smoothly. Further, although the 5-speed automatic transmission is illustrated as the transmission 5, the transmission 5 is not limited to this, and may be applied to another automatic transmission or a continuously variable transmission.

Further, in each of the above-described embodiments, a plurality of (five in FIG. 1) second clutches 9 for selectively connecting the input shaft 5a of the transmission 5 and the transmission gears 10 of the transmission 5 are provided.
Although it has been decided that each second clutch 9 be slid, instead of this, one clutch is further provided on the output shaft 5b of the transmission 5 so as to connect between the input shaft 5a of the transmission 5 and each transmission gear 10. The clutch may be completely connected and the clutch of the output shaft 5b may be in the half-clutch state. By doing so, the hydraulic control of the clutch can be simplified.

[0042]

As is apparent from the above description, the present invention has the following effects. According to the invention of claim 1,
Even if the rotation speed of the input shaft of the transmission is lower than the rotation speed required to start the engine, the engine for starting the engine can be started using the running motor. It is not necessary to provide a separate motor, and the hybrid vehicle can be constructed at low cost. Also,
Even if a high load request for starting the engine is made during low-speed traveling, the engine can be started, so that it is possible to prevent the occurrence of troubles such as the stall of the engine and the vehicle stopping. Also, since the transmission of torque from the motor to the drive wheels is not lost when the engine is started during low-speed traveling, it is possible to prevent problems such as torque loss and reduction of the required drive force when climbing slopes. There is an effect that can be.

According to the second aspect of the present invention, the remaining capacity of the battery has a margin during low speed traveling such that the rotation speed of the input shaft of the transmission is lower than the rotation speed required for starting the engine. In some cases, the vehicle will continue to run only by the motor without starting the engine, and the engine will be started only when the remaining capacity of the battery is running low. The effect that it can be achieved is produced.

Furthermore, regardless of the vehicle speed, when the remaining capacity of the battery becomes insufficient, the engine is started, so it is possible to recover the battery by the power generation by the engine and prevent the vehicle from becoming unable to run. In particular, there is an effect that the engine can be started without falling into a stalled state even during low speed traveling in which the rotation speed of the input shaft of the transmission is lower than the rotation speed required to start the engine. .

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a structure of a hybrid vehicle to which a control device according to the present invention is applied.

FIG. 2 is a block diagram showing inputs and outputs of a control device for a hybrid vehicle according to the first embodiment of the present invention.

FIG. 3 is a flowchart illustrating an engine starting procedure by the control device for a hybrid vehicle according to the first embodiment of the present invention.

FIG. 4 is a flowchart illustrating an engine starting procedure by a control device for a hybrid vehicle according to a second embodiment of the present invention.

[Explanation of symbols]

1 control device 2 hybrid vehicles 3 engine 3a Output shaft 4 motor 4a Output shaft 5 transmission 5a Input shaft 6 drive wheels 8 first clutch 9 Second clutch

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B60L 11/14 F02D 29/00 ZHVH F02D 29/00 ZHV 29/02 D 29/02 B60K 9/00 E ( 72) Inventor Masao Kubotera 1-4-1 Chuo, Wako-shi, Saitama Stock Research Institute Honda Technical Research Institute (72) Inventor Masato Fujioka 1-4-1 Chuo, Wako City Saitama Stock Research Institute Honda Technical Research Institute (72) Inventor Katsuhiro Kitamura 1-4-1 Chuo 1-chome, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (reference) 3D041 AA11 AA28 AA36 AA37 AA66 AB01 AC01 AC06 AD02 AD10 AD31 AD50 AD51 AE02 AE16 AE18 3G093 AA05 AA06 AA07 BA05 BA19 CA01 CA07 DA01 DA06 DB05 DB11 DB19 EB01 EB03 EC02 EC04 FA11 5H115 PA01 PA11 PG04 PI16 PU01 PU21 PU25 QE01 QE02 QE04 QE18 SE09

Claims (2)

[Claims] 1. An output shaft of a motor is connected to an input shaft of a transmission, an output shaft of an engine and an input shaft of the transmission are connected via a first clutch, and an input shaft of the transmission and drive wheels are connected. Second
A control device for a hybrid vehicle in which the drive wheels are driven by an engine and a motor, which are connected via a clutch.When the engine is started from the state where the drive wheels are driven by the motor, the rotation of the input shaft of the transmission is changed. If the number is below the number of revolutions required to start the engine,
A control device for a hybrid vehicle that controls to engage the first clutch while keeping the second clutch in a half-clutch state. 2. The output shaft of the motor is connected to the input shaft of the transmission, the output shaft of the engine and the input shaft of the transmission are connected via a first clutch, and the input shaft of the transmission and the drive wheels are connected. Second
A control device for a hybrid vehicle in which the drive wheels are driven by an engine and a motor, which are connected via a clutch.When the engine is started from the state where the drive wheels are driven by the motor, the rotation of the input shaft of the transmission is changed. If the number is below the number of revolutions required to start the engine,
A control device for a hybrid vehicle, which controls to engage the first clutch while keeping the second clutch in a half-clutch state only when the remaining capacity of the battery becomes equal to or less than a predetermined value.