JPH0617727A - Hybrid vehicle - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a hybrid vehicle capable of stable driving without shock when the engine is started while the motor is running alone. [Structure] To start the engine 11, a clutch ON signal is output at time t ₁ and then the engine speed N
_{When E} becomes N _E1 , the motor torque command value I _M is changed from I _M0 to I _M1 . Then, for example, when the engine starting rotational speed N _E3 of 500 rpm is reached, an ON signal such as an ignition signal is supplied to the engine controller 42. This starts the engine 11, but the motor torque current is I _M1
Therefore, the shock due to the drop in the output torque of the output shaft 16 is prevented. Furthermore, the rotational speed N _E is N _E2
At −ΔN _E2 , the dynamic friction coefficient of the clutch C increases, so that I _{M1 is changed} to I _M2 . And the rotation speed N _E is N
_When it becomes _E2 , it is judged that the engagement of the clutch C is completed, and I _M is
_Return to the value I _M0 before starting the engine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid vehicle having an engine and a motor, for example, and more particularly to a hybrid vehicle in which the engine can be started smoothly.

[0002]

2. Description of the Related Art In recent years, interest in the environment of the earth has increased, and social demands such as destruction of the natural environment due to air pollution, global warming, and prevention of deterioration of living space due to noise have increased. Along with this, an electric vehicle is attracting attention, in which an internal combustion engine such as an engine that causes exhaust gas is not used as a drive source and clean electric power is used to drive the vehicle. This electric vehicle is equipped with a large-capacity drive power supply, and the electric power supplied from this drive power supply causes an electric motor to rotate to provide a driving force for the vehicle. Then, the required torque value is calculated from the driver's operation amount such as the accelerator depression amount or the brake depression amount, and the current corresponding to the torque value is supplied to the electric motor to meet the driver's demand. Achieve proper driving.

However, this electric vehicle requires a driving power supply, and it takes a long time to charge the driving power supply. In reality, there is not necessarily sufficient equipment for charging the driving power supply. Therefore, a hybrid vehicle that combines a conventional engine that can easily supply fuel and a motor that is clean as energy has also been developed. In this hybrid type vehicle, the engine and the motor are connected by a clutch or the like, so that the motor and the engine as the drive source are appropriately switched and used according to various conditions such as the traveling speed and the traveling area. (USP4
533, 011 and JP-A-56-132102). For example, when the internal combustion engine runs at low speed where the exhaust gas is large, the motor runs alone, and when running at high speed, both the motor and the engine run or the engine runs alone.

[0004]

FIG. 10 shows the operation of a conventional hybrid vehicle when starting the engine by connecting the engine and the vehicle running motor with a clutch while the vehicle running motor is running. It is a representation
(A) shows the clutch switching timing, (b) shows the engine speed (E / G) N _E , and (c) shows the output torque. In the case of the conventional hybrid type vehicle, for example, when switching from the motor independent traveling to the engine independent traveling, when the clutch ON signal is output at time t ₁ , the engine rotation is accompanied by the engagement of the clutch after the actuator operation time Δt seconds. The number N _E begins to rise. Here, as shown in FIG. 10C, paying attention to the output torque of the hybrid vehicle, the output torque drops due to engine friction and inertia at the same time when the clutch is started (engine braking occurs). There is.

As shown in FIG. 11, the drop in the output torque is caused by the relative rotation speed ΔN (= N _E2 of the clutch).
When -N _E ) approaches 0, the coefficient of dynamic friction of the clutch (μd)
Is approaching the static friction coefficient (μs) and becomes larger, there is also a problem that the coefficient further increases immediately before the engagement of the clutch ends. The output torque becomes stable again when the relative rotational speed of the clutch is 0, that is, N _E = N _E2 and the engagement of the clutch is completed. As described above, in the conventional hybrid vehicle, when the clutch is engaged and the engine is started while the motor is traveling alone, a shock is generated due to a drop in torque, which causes a loss of a stable traveling feeling.

Therefore, an object of the present invention is to solve the above problems, and to provide a hybrid vehicle capable of stable driving without shock when the engine is started by connecting a clutch. Especially.

[0007]

According to a first aspect of the present invention, there is provided a hybrid vehicle including an electric motor and an internal combustion engine, which is driven by at least one driving force, and a clutch connecting the internal combustion engine and traveling wheels. Selecting means for selecting traveling with only the electric motor and traveling with driving by an internal combustion engine, and when the traveling with driving of the internal combustion engine is selected from traveling by only the electrode motor by the selecting means, the clutch is disengaged. The hybrid vehicle is equipped with an internal combustion engine starting means for connecting and starting the internal combustion engine, and a torque correcting means for correcting the generated torque of the electric motor when the clutch is connected, in a hybrid vehicle. To achieve. According to the invention described in claim 2, in the hybrid vehicle according to claim 1,
A detection means for detecting the degree of engagement of the clutch is provided,
The torque correction means corrects the torque corresponding to the output signal of the detection means.

[0008]

That is, when the driving accompanied by the driving of the internal combustion engine is selected from the driving only by the electric motor, the clutch for starting the internal combustion engine is connected. At this time, the torque correction means corrects the generated torque of the electric motor so as to increase it. As a result, the drive torque of the vehicle is prevented from dropping even if the clutch is engaged.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the hybrid vehicle of the present invention will be described in detail below with reference to FIGS. FIG. 1 shows a schematic configuration and circuit of a hybrid vehicle. This hybrid vehicle is the second
An engine 11 as a driving means is provided. The output shaft 12 of the engine 11 is connected to a transmission 13 that receives the rotation of the engine 11 and changes the speed to output the rotation. Output shaft 14 of this transmission 13
Is fixed to the rotor input side of the motor 15 as the first driving means. The motor 15 includes a stator and a rotor, and is rotationally driven by a drive current supplied from a power source (not shown).

The rotor output side of the motor 15 has an output shaft 1
One end of the output shaft 16 is connected, and the other end of the output shaft 16 is connected to the differential device 17. The output of the differential device 17 is transmitted through the drive shaft 18 to the drive wheels 1
9 is transmitted. In this way, the rotor of the motor 15 is connected to the output shaft 14 of the transmission 13.
And it is fixed to the output shaft 16 of the motor and integrally rotated. Therefore, both the rotation output from the transmission 13 and the rotation output from the motor 15 are transmitted to the drive wheels 19 via the output shaft 16, the differential device 17, and the drive shaft 18. In addition,
The drive wheels 19 to which the rotation from the motor 15 or the transmission 13 is transmitted are either front wheels or rear wheels.
Both can be used. Further, the motor 15 and the transmission 13 may be attached to the front and rear wheels separately.

The transmission 13 includes a planetary gear unit 22 of a single planetary type, a clutch C,
The brake B and the one-way clutch F are provided.
The planetary gear unit 22 is composed of a ring gear R, a pinion P, a carrier CR and a sun gear S. Then, the output shaft 12 of the engine 11 and the carrier CR
Is connected so that the rotation of the engine 11 is input to the carrier CR, the ring gear R and the output shaft 14 are connected, and the rotation of the transmission 13 is output from the ring gear R. Also, the sun gear S
A one-way clutch F and a clutch C are connected between the carrier CR and the carrier CR. A brake B that selectively engages the sun gear S is connected between the sun gear S and the case 23 of the hybrid vehicle.

In the transmission 13, the first speed (1s
When the brake B is released and the clutch C is engaged at the time t), the planetary gear unit 22 is brought into the direct connection state, and the rotation speed of the engine 11 is output to the output shaft 14. When the brake B is engaged and the clutch C is released at the second speed (2nd), the sun gear S is fixed, the one-way clutch F is released, the carrier CR is rotated, and the planetary gear unit 22 is overdriven. It becomes a state. As a result, the rotation accelerated from the ring gear R is output to the output shaft 14. The one-way clutch F and the clutch C are
It may be arranged between any two elements of the ring gear R, the carrier SR and the sun gear S.

The hybrid vehicle having the above-described structure is driven by the motor 15 alone in the I-th traveling mode, the engine 11 alone in the II-driving mode, and the engine 11 and the motor 15. The three traveling modes, ie, the third traveling mode in which the vehicle travels with both driving powers are automatically selected according to the traveling conditions. In the I-th traveling mode in which only the motor 15 travels, the brake B and the clutch C are released to supply the drive current to the motor 15 and stop the engine 11.
At this time, the ring gear R rotates together with the rotor of the motor 15, but the one-way clutch F becomes free and the sun gear S idles in the opposite direction, so that the stopped state of the engine 11 is maintained.

On the other hand, No. II which runs only by the engine 11
In the traveling mode, the supply of the drive current to the motor 15 is stopped, the clutch C or the brake B is engaged, and the engine 11 is stopped.
Drive only. Further, in the third mode in which both the engine 11 and the motor 15 travel, the clutch C or the brake B is engaged to supply the drive current to the motor 15 and drive the engine 11. As a result, the sum of the outputs of both the engine 11 and the motor 15 is output to the output shaft 16 to the output shaft 16.

The hybrid type vehicle is provided with a control unit 30 for driving and controlling each unit in each of the traveling modes. The control unit 30 includes a CPU (central processing unit) 31 that performs various controls, and the CPU 31 is provided with a ROM (read / write) via a bus line 32 such as a data bus.
Only memory) 33, RAM (random access
Memory) 34, output I / F (interface) unit 3
5, the input I / F unit 36 is connected. RO
The M33 stores various programs and data for the CPU 31 to determine the traveling state and the like based on various signals input from the input I / F unit 36 and to appropriately control each unit. In addition, the ROM 33 is controlled by the present embodiment from the independent operation state of the motor 15 to the engine 1
Various programs and data for performing the motor torque control operation when starting No. 1 are also stored. RAM3
Reference numeral 4 is a working memory for the CPU 31 to perform processing in accordance with programs and data stored in the ROM 33, and stores various signals input from the input I / F unit 36 and control signals output from the output I / F unit 35. Store temporarily.

The output I / F section 35 has a clutch controller 41 for controlling engagement and disengagement of the clutch C, a brake controller 44 for controlling engagement and disengagement of the brake B,
An engine controller 42 for adjusting the opening of the throttle valve and a motor controller 43 for controlling the output of the motor 15 are connected to each other. On the other hand, input I /
The F portion 36 includes a first rotation sensor 4 for detecting the rotation speed of the engine output shaft 11, that is, the rotation speed on the clutch input side.
5. Second rotation sensor 4 for detecting the rotation speed of the transmission output shaft 14, that is, the rotation speed of the clutch output side
6, vehicle speed sensor 4 for detecting the rotation speed of the motor output shaft 16
7, an accelerator sensor 48 for detecting the opening degree of the accelerator, and a brake sensor 49 for detecting the depression amount of the brake pedal are connected.

Next, the drive control operation of the hybrid vehicle constructed as described above will be described. Main operation FIG. 2 shows the operation according to the program stored in the ROM 33.
The operation of the main routine controlled by the CPU 31 is shown. The CPU 31 first calculates the motor command value after initial setting (step 11) (step 1).
2).

FIG. 3 shows a motor command value calculation operation (a) performed in step 12 and a map (b) for determining a torque command value. The program and map for performing the operation are stored in the ROM 33. It is stored. As shown in FIG. 3A, first, the CPU 31 causes the accelerator sensor 48, the brake sensor 49, and the vehicle speed sensor 4 to operate.
7, the accelerator opening, the amount of brake depression, and the vehicle speed are read (steps 121, 122, 12).
3), store in RAM 34. Then, the CPU 31
From these values stored in the RAM 34, the vehicle speed-torque command value map shown in FIG. 3B is accessed to determine the torque command value for the current vehicle speed (step 12).
4).

When the torque command value is determined in step 12 of FIG. 2, the CPU 31 supplies the determined torque command value to the motor controller 43 as a motor command value (step 13). Then, the traveling mode of the hybrid vehicle is determined from the vehicle speed and the accelerator opening stored in the RAM 34 (step 14). FIG. 4 is a map showing the relationship between the vehicle speed of the hybrid vehicle, the accelerator opening, and the traveling mode, the data of which is stored in the ROM 33. In the hybrid vehicle of this embodiment,
Any one of the traveling mode to the III-th traveling mode is selected according to the vehicle speed and the throttle opening. In FIG. 4, the speed at which the traveling mode changes and the accelerator opening degree are indicated by a solid line when they increase and a dotted line when they decrease. This Figure 4
When the traveling mode determined from the map of No. 1 and the vehicle speed is the I-th traveling mode in which the motor alone is driven (step 1
5; I), the process returns to step 12, and the motor independent traveling is continued.

On the other hand, in the II drive mode in which the engine alone is driven, the engine 11 is started (step 16). When the engine 11 is started, torque control of the motor 15, which will be described later, is performed by the torque control operation. CP
After starting the engine, U31 calculates a command value for the engine 11 (step 17). That is, CPU3
As shown in FIG. 5, 1 reads the accelerator opening detected by the accelerator sensor 48 (step 171) and sets the throttle opening to this accelerator opening (step 17).
2). This throttle opening is determined by the engine controller 42.
The engine controller 42 adjusts the throttle valve to the instructed opening (step 1
8).

Then, the CPU 31 determines the traveling mode of the hybrid type vehicle from the vehicle speed, the accelerator opening degree, etc., similarly to step 14 (step 19). When the determined traveling mode is traveling mode II (step 20; I
I), the operation from step 17 to step 19 is repeated. On the other hand, in the case of traveling mode I (step 20;
I), the engine 11 for switching to the motor independent traveling
Is stopped (step 21) and the process proceeds to step 12.

The traveling mode in step 15 is III
In the case of, that is, when the traveling from the motor independent traveling to the traveling by both the engine 11 and the motor 15 (step 1
5; III), the engine is started, which will be described later and operates under torque control (step 22). After starting the engine in step 22, or when shifting from the engine independent traveling to the traveling mode III, the CPU 31 (step 20;
III), the command value of the engine 11 and the motor 15 is calculated (step 23).

FIG. 6 is for calculating the command values of the engine 11 and the motor 15, and (a) shows the calculation operation.
(B) is a map for calculating the torque command value,
(C) shows respective maps for calculating the throttle opening. The program for performing the operation of (a) and the maps of (b) and (c) are stored in the ROM 33.
It is stored in. As shown in FIG. 6A, the CPU 3
1 reads the accelerator opening detected by the accelerator sensor 48 (step 231), detects the vehicle speed detected by the vehicle speed sensor 47 (step 232), and stores both in the RAM 34.

Then, the CPU 31 calculates a motor torque command value from the detected vehicle speed and accelerator opening according to the map shown in FIG. 6B and stores it in the RAM 34 (step 233). Further, the throttle opening is calculated from the accelerator opening according to the map shown in FIG. 6C and stored in the RAM 34 (step 234). The CPU 31 commands the motor controller 43 to store the throttle opening stored in the RAM (step 24) and commands the motor torque command value to the motor controller 43 (step 25). After that, the routine proceeds to step 19, the traveling mode is determined, and traveling in the determined mode is continued.

Torque Control Next, the torque control performed in the engine starting operation in steps 16 and 22 in FIG. 2 will be described. FIG. 7 shows an operation of the first motor torque control at the time of starting the engine, and FIG. 8 shows a time chart at the time of starting the engine. Before starting the engine, as shown in FIG. 8, the clutch signal supplied to the clutch controller 41 is OFF (a), and the engine rotation N detected by the first rotation sensor 45 is N. It is assumed that _E is 0 [rpm] (b), the injection (INJ) signal is OFF (c), and the motor torque command value I _M is the torque command value I _M0 calculated in step 12.

In this state, when mode II or mode III is selected from mode I and the engine 11 is started, the CPU 31 switches the clutch signal to ON as shown in FIG. It is supplied to the clutch controller 41 (step 161). afterwards,
The CPU 31 continuously monitors the rotation speed N _{E of the} engine 11 (FIG. 8B) detected by the first rotation sensor 45. The engine speed N _E of the engine 11 is 0 [rpm]
From N _E1 or more is detected (step 16
2; Y), the CPU 31 recognizes that the engagement of the clutch C has started, and as shown in FIG. 8D, sets the motor torque command value I _M that was I _M0 to I _M1 (step 16
3) Start motor torque control. The timing for setting the motor torque command value I _M to I _M1 may be set by a timer after the time Δt from the clutch signal ON at time t1.

The engine speed N _{E of the} engine 11 is, for example, 5
When it is detected that the engine start rotational speed N _{E3 of} 00 [rpm] is exceeded (step 164; Y), the CPU 31
Supplies an INJ ON signal to the engine controller 42 (step 165). As a result, the engine 11 starts, but this motor torque command value is secured at I _M1 , so a shock due to a drop in the output torque of the output shaft 16 is prevented.

Further, the rotational speed N _E of the engine 11 is N _E2 −
When it is detected that ΔN _E2 or more is reached (step 16
6), the CPU 31 recognizes that it is the end stage of the clutch C engagement. Here, N _E2 is the clutch output rotational speed detected by the second rotation sensor 46, and ΔN _E2 is a constant.
At the end stage of the engagement of the clutch C, as shown in FIG. 11, the relative rotational speed ΔN (= N _E2 −N _E ) of the clutch is 0.
As the dynamic friction coefficient (μd) of the clutch approaches the static friction coefficient (μs), the motor torque command value I _M , which is I _M1 , is further increased to I _M2 (step 167).

The engine speed N _E of the engine 11 is N _E2
When it is detected (step 168), the CPU
31 determines that the engagement of the clutch C is completed,
The motor torque command value I _M is the value I before starting the engine start.
Return to _M0 (step 169) and return.

FIG. 9 shows a time chart of the second motor torque control operation performed in the operations of steps 16 and 22 shown in FIG. In the second motor torque control, the rotation speed N _E of the engine 11 changes from N _E3 to N _E2 −Δ.
The motor torque command value I _{M is set} to I _M3 lower than I _M1 until N _E2 . In the first motor torque control, the engine 11 is started when the INJ signal is turned ON, so that torque is generated by the engine 11 and the combined torque of the output shaft 16 is slightly increased. This increase in torque is prevented by setting the motor torque command value I _M to I _M3, which is lower than I _M1 , and smoother operation becomes possible.

In the first and second motor torque control described above, the motor torque command values I _M1 , I _M2 and I _M3 are set to constant values, but the present invention is not limited to this. For example, it may be changed according to the rate of change of the engine speed N _E of the engine 11. Further, in the embodiment described above, the structure of the transmission 13 as shown in FIG. 1 is adopted as the structure of the hybrid vehicle, but the present invention is not limited to this structure.
The transmission may have another configuration, or the output shaft 12 of the engine 11 and the rotor shaft of the motor 15 may be simply connected by a wet clutch.
Further, in the embodiment, the clutch output speed is detected by the second rotation sensor 46, but in the present invention, the vehicle speed sensor 47 may also be used.

By the way, the rotation speed detecting means is used to detect the degree of engagement of the clutch in order to calculate the magnitude of the torque drop due to the engagement of the clutch C. Instead of this, for example, the engagement hydraulic pressure of the clutch may be detected by a hydraulic pressure sensor or the like, and the degree of engagement of the clutch may be detected based on the detected hydraulic pressure. Further, the following means may be used instead of detecting the degree of engagement of the clutch and controlling the motor torque based on the detected degree. For example, after the clutch that connects the engine and the motor (on the wheel side)
If there is a torque converter in the torque converter, the rotational speed difference between the pump of the torque converter and the turbine is calculated, and the motor torque is controlled so that this fluctuation does not occur, or the rotational speed of the output shaft is detected to determine the change rate. It is also possible to control the motor torque by looking at. The same control can be performed by detecting the rate of change of the engine speed. Further, in the embodiment, the driving mode of the hybrid vehicle is automatically determined from the vehicle speed and the accelerator opening, but in the present invention, the driving vehicle may freely select the driving mode. Even in this case, the motor torque control is performed when the engine is started.

[0033]

According to the present invention, when the driving accompanied by the driving of the internal combustion engine is selected from the driving only by the electric motor and the clutch for starting the internal combustion engine is connected, the torque generated by the electric motor is increased. Since the torque correction means for correction is provided, the driving torque of the vehicle is prevented from dropping even if the clutch is engaged, and stable traveling is possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration and a circuit of a hybrid vehicle according to an embodiment of the present invention.

FIG. 2 is a flowchart of a main routine operation controlled by the hybrid vehicle in the same as above.

FIG. 3 is a diagram showing a flowchart (a) of a motor command value calculation operation in the main routine operation and a map (b) for determining a motor command value.

FIG. 4 is an explanatory diagram showing a relationship between a vehicle speed, an accelerator opening degree, and a traveling mode of the hybrid vehicle.

FIG. 5 is a flowchart of an engine command value calculation operation in the main routine operation of the above.

FIG. 6 is a diagram showing an operation for calculating an engine command value and a motor command value in the main routine operation (a), a map for calculating a torque command value (b), and a map for calculating a throttle opening (c). FIG.

FIG. 7 is a flowchart showing a first motor torque control operation at the time of engine startup in the main routine operation of the above.

8 is a time chart corresponding to FIG. 7 above.

FIG. 9 is a time chart of the second motor torque control operation of the above.

FIG. 10 is a time chart of an engine starting operation by a conventional hybrid vehicle.

FIG. 11 is an explanatory diagram showing the relationship between the relative rotational speed of the clutch and the friction coefficient.

[Explanation of symbols]

 11 Engine 13 Transmission 15 Motor 30 Control Unit 31 CPU 33 ROM 34 RAM 41 Clutch Controller 42 Engine Controller 43 Motor Controller 45 First Rotation Sensor 46 Second Rotation Sensor 47 Vehicle Speed Sensor 48 Accelerator Sensor 49 Brake Sensor C Clutch

Claims (2)

[Claims] 1. A hybrid vehicle including an electric motor and an internal combustion engine, which is driven by at least one driving force, a clutch connecting the internal combustion engine and traveling wheels, traveling by only the electric motor, and at least the internal combustion engine. Selection means for selecting traveling with driving, and internal combustion engine starting means for connecting the clutch to start the internal combustion engine when traveling with driving of the internal combustion engine is selected from traveling with only the electrode motor by the selection means. And a torque correction unit that corrects the generated torque of the electric motor so as to increase when the clutch is connected. 2. The hybrid type according to claim 1, further comprising a detection unit that detects a degree of engagement of the clutch, and the torque correction unit corrects a torque corresponding to an output signal of the detection unit. vehicle.