JP2004138030A - Hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for stabilizing engine speed by maintaining the engine speed during the shift at an idling speed or over in a hybrid vehicle. <P>SOLUTION: A hybrid vehicle having an engine and an electric motor comprises a transmission for automatically operating a clutch during the shift, an engine control device to control the operation of the engine, and a transmission control device for controlling the clutch operation of the transmission and the engine for controlling the engine during the clutch operation. When the vehicle is decelerated, and the clutch is uncoupled by the transmission, the engine is controlled not by the transmission control device but by the engine control device. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hybrid vehicle, and more particularly to a hybrid vehicle including a transmission that automatically performs a clutch operation.
[0002]
[Prior art]
2. Description of the Related Art There has been known a device that performs clutch-to-clutch shifting satisfactorily, prevents an abnormal increase in engine speed, and performs integrated control of an automatic transmission and an engine having excellent acceleration characteristics (for example, see Patent Document 1). ).
[0003]
Further, in an electric vehicle driven by an internal combustion engine driven by electric power from a generator driven by the internal combustion engine, a braking control device that utilizes 100% of an engine braking performance possessed by the internal combustion engine during a braking operation is known (for example, a braking control device is known). , Patent Document 2).
[0004]
Further, there has been known a hybrid vehicle including an engine and a motor that has a plurality of engine output characteristics to improve fuel efficiency and exhaust emission performance in a wide operating state (for example, see Patent Document 3).
[0005]
[Patent Document 1]
Japanese Patent No. 2947537 (pages 3-5)
[Patent Document 2]
Japanese Patent Publication No. 4-47527 (page 4-5)
[Patent Document 3]
Japanese Patent Application Laid-Open No. H11-311137 (page 3-1)
[0006]
[Problems to be solved by the invention]
By the way, in a hybrid vehicle including a transmission that automatically performs a clutch operation, an engine, and a motor, engine control at the time of shifting is performed by a control device of the transmission so that shifting is performed smoothly. . However, when the vehicle is decelerated, regeneration is performed to convert the kinetic energy of the vehicle into electric energy, so that the clutch is disengaged. For this reason, the engine output is suppressed, and the engine speed may be lower than the normal idle speed. In such a case, the engine control device increases the engine speed in an attempt to maintain the engine speed at the normal idle speed. If such operations are repeatedly performed, the engine speed becomes unstable.
[0007]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and provides a technique for stabilizing the engine speed in a hybrid vehicle by keeping the engine speed during shifting at or above an idle speed. Aim.
[0008]
[Means for Solving the Problems]
To achieve the above object, the hybrid vehicle of the present invention employs the following solutions. That is,
In a hybrid vehicle equipped with an engine and an electric motor,
A transmission in which clutch operation is automatically performed during gear shifting;
An engine control device that controls the operation of the engine;
A transmission control device that performs clutch operation control of the transmission and engine control at the time of clutch operation;
With
When the vehicle is decelerating and when the clutch is disengaged by the transmission, the engine is controlled by the engine control device regardless of the transmission control device.
[0009]
The most significant feature of the present invention is that the engine control is performed by the engine control device when the vehicle is decelerated and the clutch is operated by the transmission, so that the normal idle rotation that occurs when the transmission control device controls the engine is performed. Another object is to suppress a decrease in the engine speed.
[0010]
In the hybrid vehicle configured as described above, engine control different from that during normal operation is required at the time of shifting, and thus the engine control is performed by the transmission control device. However, at the time of deceleration, the clutch is disengaged and the engine output is suppressed, so that the engine speed becomes equal to or lower than the idle speed. Therefore, when the vehicle is decelerating and the clutch is disengaged by the transmission, the engine control is performed by the engine control device instead of the transmission control device, thereby suppressing a decrease in the engine speed.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, specific embodiments of the hybrid vehicle according to the present invention will be described with reference to the drawings.
[0012]
FIG. 1 is a diagram showing a schematic configuration of a hybrid vehicle according to the present embodiment.
[0013]
The hybrid vehicle according to the present embodiment includes a diesel engine 1, a transmission 30, a power split device 31, a motor generator 32, a battery 33, an inverter 34, an axle 35, a speed reducer 36, and wheels 37. The power split mechanism 31 includes a planetary gear therein, and splits the power generated from the engine 1 into the motor generator 32 and the axle 35. Motor generator 32 rotates in proportion to axle 35 via reduction gear 36. The motor generator 32 assists the output of the engine 1 as needed during normal operation, and functions as a generator during braking to recover energy. Further, motor generator 32 obtains power from engine 1 to generate power and charge battery 33.
[0014]
A joint between the transmission 30 and the engine 1 is provided with a clutch 30a. At the time of shifting, the clutch 30a is operated by a shift control unit 3 described later, and gear operation is performed by the driver. As described above, in the present embodiment, a transmission in which the operation of the clutch 30a is automatically performed is employed. The transmission 30 has a plurality of gears, and a gear suitable for the engine speed and the vehicle speed is selected by the driver and manually changed. Instead of this, the present invention is also applicable to a transmission in which a gear is automatically selected regardless of a driver, that is, a so-called automatic transmission.
[0015]
The engine 1 is provided with an electronic control unit (ECU: Electronic Control Unit) 2 for controlling the engine 1. The ECU 2 is a unit that controls the operating state of the engine 1 according to the operating conditions of the engine 1 and the driver's requirements.
[0016]
The ECU 2 is connected with various sensors via an electric wiring, in addition to an accelerator opening sensor 4 for outputting an electric signal corresponding to the amount of depression of the accelerator by the driver, and the output signals of the various sensors are input to the ECU 2. It is supposed to be. The ECU 2 stores various application programs and various control maps.
[0017]
On the other hand, the transmission 30 is provided with a shift control unit 3 for controlling the transmission 30. The transmission control unit 3 for controlling the transmission 30 is also connected to the ECU 2 via wiring, and data transmission and reception are performed between the ECU 2 and the transmission control unit 3. When the driver performs a shift operation, the shift control unit 3 disengages the clutch 30a, and after the driver manually changes the gear, the shift control unit 3 engages the clutch 30a. The clutch is operated by, for example, hydraulic pressure, and the clutch operation is performed by controlling the hydraulic pressure by the transmission control unit 3. Further, the clutch 30a may be operated by a motor.
[0018]
In the hybrid system thus configured, the wheels 37 are driven by the output of the engine 1 or the output of the motor generator 32 during normal traveling. On the other hand, at the time of deceleration, the kinetic energy can be converted to electric energy and collected by the battery 33 while the motor generator 32 is operated as a generator by the rotational force of the wheels 37 to reduce the speed. As described above, the kinetic energy is converted into the electric energy when the vehicle is decelerated, so that the vehicle can be decelerated.
[0019]
FIG. 2 is a time chart showing the transition of the engine output and the priority request flag over time during shifting by a conventional hybrid vehicle. Here, the priority request flag is a flag that is turned on during a vehicle shift, and the operation control of the engine 1 during this time is preferentially performed by the shift control unit 3.
[0020]
In the region (1), the engine 1 is performing a steady operation. In this case, the priority request flag is OFF. In the region (2), the driver is not depressing the accelerator, and the vehicle is decelerating. The shift down of the transmission 30 is performed according to the reduced speed. In this area, the priority request flag is turned ON, and the shift control unit 3 performs engine control and downshifting of the transmission 30. During deceleration, the clutch 30a is disengaged by the transmission control unit 3. In the region of (3), the rotation speed of the engine 1 is the rotation speed at the time of idling. The engine control is performed by the shift control unit 3. In the region of (4), the rotation speed of the engine 1 is increased, and the speed of the vehicle and the rotation speed of the transmission 30 are matched. Thus, the occurrence of an impact due to the rotational speed imbalance when the clutch 30a is engaged is suppressed. The increase in the engine speed at this time is controlled by the shift control unit 3. In the region (5), the engine 1 is performing a steady operation. At this time, the priority request flag is turned off.
[0021]
By the way, as described above, downshifting is performed by the shift control unit 3 when the vehicle is decelerated. When the vehicle is decelerated, the clutch 30a is disengaged to supply a large amount of energy to the motor generator 32. In such a state, downshifting can be performed more smoothly by controlling the engine from the shift control unit 3 than by controlling the engine from the ECU 2. In this case, the output of the engine 1 is suppressed, and the engine speed becomes equal to or lower than the idle speed. However, the engine 1 is controlled (ISC control) to keep the engine speed at or above the idle speed in order to prevent engine stall. As described above, when the engine control and the ISC control from the shift control unit 3 are performed, the engine speed becomes unstable.
[0022]
Therefore, in the present embodiment, in order to stabilize the engine speed at the time of vehicle deceleration, when the vehicle is decelerated and the clutch 30a is disengaged, the engine 1 (ECU 2) is used instead of the transmission 30 (transmission control unit 3). 1 operation control is performed.
[0023]
Next, engine control according to the present embodiment will be described.
[0024]
FIG. 3 is a flowchart illustrating a flow of engine control according to the present embodiment.
[0025]
In step S101, it is determined whether the vehicle is in a decelerating state. The speed of the vehicle is obtained from the rotation speed of the transmission 30 and the like. When the rotation speed decreases, it is determined that the vehicle is in a deceleration state.
[0026]
If an affirmative determination is made in step S101, the process proceeds to step S102, while if a negative determination is made, this routine ends.
[0027]
In step S102, the clutch 30a of the transmission 30 is disengaged. The energy consumed by the engine 1 at the time of deceleration is cut off, and the energy conversion rate is improved.
[0028]
In step S103, it is determined whether the accelerator opening is zero. The accelerator opening is a value indicating the degree when the driver depresses the accelerator. The accelerator opening is 0% when the driver is not depressing the accelerator, and the accelerator opening is 100% when the accelerator is fully depressed. %. When the accelerator opening becomes 0, it is determined whether or not the driver requests deceleration of the vehicle. The accelerator opening is obtained from the output signal of the accelerator opening sensor 4.
[0029]
If an affirmative determination is made in step S103, the process proceeds to step S104, while if a negative determination is made, the process proceeds to step S109.
[0030]
In step S104, it is determined whether the priority request flag is ON.
[0031]
If an affirmative determination is made in step S104, the process proceeds to step S105, while if a negative determination is made, the process proceeds to step S107.
[0032]
In step S105, a shift control is performed.
[0033]
In step S106, the operation of the engine 1 is controlled by the engine (ECU2).
[0034]
In step S107, no shift control is performed.
[0035]
In step S108, the operation control of the engine 1 is performed by the engine (ECU2).
[0036]
In step S109, no shift control is performed.
[0037]
In step S110, the clutch 30a is engaged.
[0038]
In this way, the operation of the engine 1 is controlled by the ECU 2 when the transmission 30 shifts.
[0039]
FIG. 4 is a time chart showing the time transition of the engine speed when the operation of the engine 1 is controlled by the transmission 30 (transmission control unit 3) and the engine 1 (ECU 2).
[0040]
As described above, when the priority request flag is turned on at the time of deceleration of the vehicle, when the engine control is performed on the transmission 30 side (transmission control unit 3), the engine speed becomes unstable, but the engine 1 side (ECU 2) When the engine control is performed, the engine speed is stabilized.
[0041]
As described above, in the hybrid vehicle according to the present embodiment, when the vehicle is decelerated, the engine control and the ISC control from the transmission control unit 3 are performed, and the engine speed is prevented from becoming unstable.
[0042]
【The invention's effect】
In the hybrid vehicle according to the present invention, during deceleration and when the clutch is disengaged, engine control is performed by the engine control device without using the shift control device, and the engine speed can be stabilized.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of a hybrid vehicle according to the present embodiment.
FIG. 2 is a time chart showing a transition of an engine output and a priority request flag over time during shifting by a conventional hybrid vehicle.
FIG. 3 is a flowchart showing a flow of engine control according to the embodiment.
FIG. 4 is a time chart showing a time transition of the engine speed when the operation control of the engine is performed by the transmission side and the engine side.
[Explanation of symbols]
1 ... Engine 2 ... ECU
3 .... Transmission control unit 4 ... Accelerator opening sensor 30 ... Transmission 30a ... Clutch 31 ... Power split mechanism 32 ... Motor generator 33 ... Battery 34 ... Inverter 35 ... Axle 36 ... Reducer 37 ... Wheel

Claims (1)

In a hybrid vehicle equipped with an engine and an electric motor,
A transmission in which clutch operation is automatically performed during gear shifting;
An engine control device that controls the operation of the engine;
A transmission control device that performs clutch operation control of the transmission and engine control at the time of clutch operation;
With
A hybrid vehicle, wherein the engine is controlled by the engine control device regardless of the transmission control device during vehicle deceleration and when the clutch is disengaged by the transmission.

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