JP2014159207A - Engine start control device for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine start control device for a hybrid vehicle that is capable of starting an engine in accordance with the driving situation.SOLUTION: A hybrid vehicle 10 includes an engine 11, a motor 12, a clutch 13, a control unit 20, an accelerator sensor 31, a vehicle speed sensor 32, and an engine speed sensor 33. When an engine start request is made during driving, whether or not an accelerator opening exceeds a predetermined value is determined. When the accelerator opening exceeds the predetermined value, a transmission torque of the clutch 13 is switched to a first transmission torque so that the engine starts by output torque of the motor 12. When the speed of the engine 11 exceeds a predetermined value, the transmission torque is switched to a second transmission torque having a smaller torque transmission ratio than the first transmission torque, so as to maintain the rotation of the engine 11. When completion of the starting is determined, the transmission torque is switched to a third transmission torque having a maximum torque transmission ratio, and the output torque of the engine 11 is transmitted to wheels 18 via the clutch 13.

Description

  The present invention relates to an engine start control device applied to a hybrid vehicle having a clutch between a traveling engine and a motor.

  An example of a hybrid vehicle has a traveling engine (internal combustion engine), an electric motor (hereinafter simply referred to as a motor), and a clutch, and travels using only the motor and the engine in combination according to traveling conditions and the like. It is configured to be able to switch to hybrid running or engine-only running. For example, in the hybrid vehicle disclosed in Patent Document 1, the engine is started by connecting a clutch when the vehicle is driven by a motor, and half-clutch control is performed in which the clutch is slid when the engine is started. ing. The hybrid vehicle of Patent Document 2 is also configured to start an engine by connecting a clutch when the vehicle is running by a motor, and performs a half-clutch control that slides the clutch when starting the engine. Yes.

JP 2010-215097 A Japanese Patent No. 5009449

  Patent Document 1 and Patent Document 2 disclose that the clutch is brought into a so-called half-clutch state when the engine is started. However, simply using a half-clutch makes it possible to meticulously respond to various driving conditions such as when the vehicle is running (for example, when the accelerator opening is large, when the vehicle is traveling at a low opening and high vehicle speed, or when driving at a low opening and low vehicle speed). The engine is not always started.

  For example, when a rapid increase in output is required (such as when starting up a high opening), such as when suddenly accelerating or climbing up a steep slope while traveling by a motor, the engine is started quickly and the output is turned on. Although it is necessary to increase the engine speed, it may not be possible to start the engine quickly by simply starting the engine in a half-clutch state, and responsiveness when the accelerator pedal is greatly depressed becomes a problem. On the other hand, if the engine is started when the vehicle is traveling at high speed (low opening high vehicle speed starting), if the engine is started in a half-clutch state with a transmission torque equivalent to that at the time of high opening starting, Since most of the output torque is distributed for starting the engine, there may be a shortage of output as a driving feeling.

  Accordingly, an object of the present invention is to provide an engine start control device capable of starting an engine in accordance with a traveling state when the vehicle is driven by a motor in a hybrid vehicle including an engine, a motor, and a clutch.

  One embodiment of the present invention is an engine start control device for a hybrid vehicle in which a clutch (13) is disposed between a traveling engine (11) and a motor (12), and detects an accelerator opening. Means (31), means (32) for detecting the vehicle speed, means (ST1) for determining whether or not the engine (11) is requested to start, and the engine (11) while the vehicle is running by the motor (12). And a torque switching means (20) for switching the transmission torque of the clutch (13) according to the accelerator opening and the vehicle speed when there is a start request.

  The engine further includes a means (33) for detecting the engine speed, and the torque switching means (20) is an example of a high opening start that is executed when the accelerator opening exceeds a predetermined value (A1). Includes mode (1). An example of the high opening start mode (1) is that the engine (11) is started by switching the clutch (13) to the first transmission torque (CL1), and the engine speed exceeds a predetermined value (R1). The clutch (13) is switched to a second transmission torque (CL2) having a torque transmission rate smaller than that of the first transmission torque (CL1). Means (ST3-ST7) for switching to a third transmission torque (CL3) larger than the second transmission torque (CL1, CL2) is provided. An example of the third transmission torque (CL3) is a transmission torque having a torque transmission rate of 100% which brings the engine (11) and the motor (12) into a direct connection state.

  An example of the torque switching means (20) is a low opening high vehicle speed start executed when the accelerator opening does not exceed a predetermined value (A1) and the vehicle speed exceeds a predetermined value (S1). Mode (2) and a low opening low vehicle speed start mode (3) executed when the accelerator opening does not exceed the predetermined value (A1) and the vehicle speed does not exceed the predetermined value (S1). Is included.

  One example of the low opening high vehicle speed start mode (2) is that the clutch (13) has a torque transmission rate smaller than that of the first transmission torque (CL1) and torque transmission of the second transmission torque (CL2). The engine (11) is started by switching to the fourth transmission torque (CL4) having a large rate, and when the engine speed exceeds a predetermined value (R1), the clutch (13) is moved to the fourth transmission torque (CL4). There is a means (ST9-ST12) for switching the clutch (13) to the third transmission torque (CL3) when it is determined that the start has been completed. doing.

  An example of the low opening low vehicle speed start mode (3) is that when the vehicle speed does not exceed a predetermined value (S1), the clutch (13) has a torque transmission rate smaller than the first transmission torque (CL1) and the The engine (11) is started by switching to the sixth transmission torque (CL6) having a torque transmission rate larger than that of the second transmission torque (CL2). Means (ST13, ST14) for switching to the transmission torque (CL3).

  A means (33) for detecting the engine speed is further provided, and an example of the torque switching means is a high vehicle speed start mode that is executed when the vehicle speed exceeds a predetermined value (S1) regardless of the accelerator opening. The high vehicle speed start mode includes starting the engine (11) by switching the clutch (13) to the fourth transmission torque (CL4), and the engine speed exceeds a predetermined value (R1). The clutch (13) is switched to the fifth transmission torque (CL5) having a torque transmission rate smaller than that of the fourth transmission torque (CL4). And a means for switching to a third transmission torque (CL3) larger than the transmission torque (CL4, CL5) of 5.

  According to the present invention, in a hybrid vehicle including an engine, a motor, and a clutch, engine transmission corresponding to the traveling state is performed by switching the transmission torque of the clutch according to the accelerator opening and the vehicle speed during traveling by the motor. Can be performed. For example, at the time of high opening start, the clutch is set to the first transmission torque, so that the output torque of the motor can be transmitted to the engine in a short time to start quickly. For example, at the time of low opening high vehicle speed start, the engine is started by switching the clutch to the fourth transmission torque, and after the start, the motor is switched to the second transmission torque that can maintain the rotation of the engine. The ratio of distributing the output to the drive wheels can be increased.

The figure which shows typically the structure of the hybrid vehicle provided with the engine starting control apparatus which concerns on one embodiment of this invention. The time chart which shows the relationship between the clutch transmission torque and the rotation speed in the high opening start mode of the hybrid vehicle shown in FIG. The time chart which shows the relationship between the clutch transmission torque in the low opening high vehicle speed start mode of the hybrid vehicle shown by FIG. 1, and rotation speed. The time chart which shows the relationship between the clutch transmission torque and low speed in the low opening low vehicle speed start mode of the hybrid vehicle shown by FIG. The flowchart which shows the flow of a process of the engine starting control apparatus of the hybrid vehicle shown by FIG.

Hereinafter, a hybrid vehicle including an engine start control device according to one embodiment of the present invention will be described with reference to FIGS. 1 to 5.
A hybrid vehicle 10 shown in FIG. 1 includes a traveling engine 11 and a traveling motor 12. The motor 12 is rotated by electric power supplied from the driving battery. A clutch 13 is disposed between the engine 11 and the motor 12. A power transmission mechanism 17 including a transmission 15 and a differential 16 is connected to the output shaft 14 of the motor 12. When the clutch 13 is connected, the engine 11 and the motor 12 are connected in series, so that the output shaft 14 is rotated by the torque output by the engine 11 and the torque output by the motor 12. When the clutch 13 is disengaged, the wheel 18 is rotated only by the output of the motor 12.

  The clutch 13 is connected and disconnected by the actuator 13a, and the clutch transmission torque (sometimes referred to simply as transmission torque in this specification) can be changed according to the operation stroke of the actuator 13a. Yes. The actuator 13a has, for example, a piston that is operated by hydraulic pressure, and changes the transmission torque of the clutch 13 according to the position of the piston. However, in addition to the hydraulic pressure, for example, an electric, mechanical, fluid, or magnetic actuator may be used. The torque transmission rate when the clutch 13 is completely connected is substantially 100%, and the engine 11 and the motor 12 are directly connected. The torque transmission rate when the clutch 13 is disengaged is substantially zero.

  The hybrid vehicle 10 includes a control unit 20 that electronically controls the engine 11, the motor 12, the actuator 13a of the clutch 13, and the like. The control unit 20 includes an engine control unit 21 that controls the engine 11, a motor control unit 22 that controls the motor 12, an ECU (Electrical Control Unit) 23 that also functions as an engine start control device, a clutch control unit 24, and the like. Is included. The motor control unit 22 changes the output torque generated by the motor 12 by controlling the current supplied to the motor 12 based on the instruction torque applied to the motor 12.

  The hybrid vehicle 10 also includes an accelerator sensor 31 that detects the amount of operation of the accelerator pedal 30, a vehicle speed sensor 32 that functions as a means for detecting the speed of the vehicle 10 (hereinafter referred to as vehicle speed), and the rotational speed of the engine 11. An engine speed sensor 33 that functions as a means for detecting When the accelerator pedal 30 is depressed in the direction of arrow A in FIG. 1, the accelerator opening detected by the accelerator sensor 31 increases as the depression amount increases. That is, the accelerator sensor 31 of this embodiment functions as a means for detecting the accelerator opening.

  The engine speed (rpm) detected by the engine speed sensor 33 is input to the ECU 23 of the control unit 20. The engine rotational speed corresponds to the rotational speed of the crankshaft 11a, but the rotational speed of the crankshaft 11a per unit time may be used.

  The control unit 20 also has a function as an engine start control device that changes the transmission torque of the clutch 13 (for example, the operation stroke of the actuator 13a) according to the traveling state of the vehicle 10. The actuator 13a of the clutch 13 is controlled by the clutch control unit 24 of the control unit 20, and changes the torque transmission rate between zero and 100% according to the driving situation of the vehicle 10 as will be described later. That is, the control unit 20 incorporates a computer program that functions as a torque switching means for switching the transmission torque of the clutch 13 in accordance with the traveling state when an engine start request is detected.

  2 to 4 show changes in the clutch transmission torque, the motor rotation speed, and the engine rotation speed with respect to the time axis (horizontal axis) when the engine 11 is started when the vehicle 10 is running by the motor 12, respectively. Show. Hereinafter, FIGS. 2 to 4 will be described.

FIG. 2 shows "(1) high opening start mode", that is, the engine 11 is started when the accelerator opening (output request) is large during traveling by the motor 12, such as during rapid acceleration, traveling uphill, or loading heavy objects. 2A shows the clutch transmission torque, and FIG. 2B shows changes in the motor speed and the engine speed. 2, is between the time t ₀ of t1, the vehicle 10 is to travel only by motor 12, the clutch torque is zero.

  If there is an engine start request at time t1 in FIG. 2, the clutch 13 is switched to the first transmission torque CL1, whereby the output torque of the motor 12 is transmitted to the engine 11 via the clutch 13, and the engine 11 is closed. Ranked. Since the first transmission torque CL1 has a relatively large torque transmission rate, a shock is generated at the time of connection, but the engine 11 can be started quickly.

  When the engine 11 is started, the clutch 13 is switched to the second transmission torque CL2 at time t2 in FIG. The second transmission torque CL2 has a torque transmission rate smaller than that of the first transmission torque CL1. For example, if the torque transmission rate in the clutch direct connection state is 100%, the torque transmission rate of the first transmission torque CL1 is 60%, for example, and the torque transmission rate of the second transmission torque CL2 is 30%, for example. The second transmission torque CL2 has a torque transmission rate that can maintain the rotation of the engine 11, and priority is given to acceleration by the motor torque.

  When it is determined at time t3 in FIG. 2 that the start is completed, the clutch 13 is switched to the third transmission torque CL3. Whether or not the start has ended is determined by, for example, the control unit 20 determining whether or not the engine speed detected by the engine speed sensor 33 has reached a stable value (for example, the same value as the motor speed). Done. The third transmission torque CL3 has a torque transmission rate of substantially 100%, that is, a clutch directly connected state, whereby the output torque of the engine 11 is transmitted to the wheels 18 via the clutch 13, the motor 12, and the power transmission mechanism 17. It is transmitted.

FIG. 3 shows “(2) Low opening high vehicle speed start mode”, that is, the case where the engine 11 is started when the motor 12 is traveling at high speed and the accelerator opening is small. In FIG. 3, since the vehicle 10 travels only by the motor 12 from time t ₀ to time t ₁ , the clutch transmission torque is zero.

  When there is an engine start request at time t <b> 1 in FIG. 3, the output torque of the motor 12 is transmitted to the engine 11 via the clutch 13 by switching the clutch 13 to the fourth transmission torque CL <b> 4. As a result, the engine 11 is started by cranking the engine 11.

  Since the fourth transmission torque CL4 has a smaller torque transmission rate than the first transmission torque CL1 (shown in FIG. 2), the start-up of the fourth transmission torque CL4 is slow compared with the case of starting with the first transmission torque CL1. , That much shock is suppressed. For example, assuming that the torque transmission rate in the clutch direct connection state is 100%, the torque transmission rate of the fourth transmission torque CL4 is, for example, 50%.

  When the engine 11 is started, the clutch 13 is switched to the fifth transmission torque CL5 at time t2 in FIG. 3, so that the motor torque is largely distributed to the drive side (power transmission mechanism 17). The fifth transmission torque C5 may be the same value as or different from the second transmission torque CL2 described in “(1) High opening start mode”. For example, the torque transmission rate of the second transmission torque CL2 may be 30%, and the torque transmission rate of the fifth transmission torque CL5 may be 40%. In this case, the second transmission torque CL2 in the high opening start mode has a torque transmission rate smaller than the fifth transmission torque CL5 in the low opening high vehicle speed start mode.

  When it is determined that the start is completed at time t3 in FIG. 3, the output torque of the engine 11 is changed from the clutch 13 to the motor 12 by switching the clutch 13 to the third transmission torque CL3 as in FIG. And transmitted to the wheel 18 via the power transmission mechanism 17.

FIG. 4 shows “(3) Low opening low vehicle speed start mode”, that is, the case where the engine 11 is started when the motor 12 is traveling at a low speed and the accelerator opening is small. 4, during the time t ₀ of t1, the vehicle 10 is to travel only by motor 12, the clutch torque is zero.

  If there is an engine start request at time t1 in FIG. 4, the clutch 13 is switched to the sixth transmission torque CL6. The sixth transmission torque CL6 is maintained until time t3 (end of starting). The sixth transmission torque CL6 may be the same value as or different from the fourth transmission torque CL4 described in “(2) Low opening high vehicle speed start mode”. For example, the torque transmission rates of the fourth transmission torque CL4 and the sixth transmission torque CL6 are 50%, respectively. After time t3 (end of starting), the clutch 13 is switched to the third transmission torque CL3, so that the output torque of the engine 11 is transmitted to the wheels 18 via the clutch 13, the motor 12, and the power transmission mechanism 17.

Below, the flow of the process of the engine start control apparatus provided with the control part 20 of this embodiment is demonstrated with reference to the flowchart of FIG.
In step ST1 of FIG. 5, it is determined whether there is an engine start request. The presence / absence of the start request may be determined based on, for example, a signal from the engine control unit 21. In that case, the engine control unit 21 functions as means for determining whether or not there is a request to start the engine 11. If it is determined in step ST1 that there is a start request (“YES” in step ST1), the process proceeds to step ST2. If there is no start request (“NO” in step ST1), the engine start control described below is not performed and the process ends.

  In step ST2, the accelerator opening is compared with a predetermined value A1. The accelerator opening can be obtained by the output of the accelerator sensor 31, for example. If it is determined that the accelerator opening exceeds the predetermined value A1 ("YES" in step ST2), the process proceeds to step ST3. If the accelerator opening does not exceed the predetermined value A1 ("NO" in step ST2), the process proceeds to step ST8.

  Steps ST3 to ST7 correspond to the “(1) high opening start mode” described in FIG. In step ST3, the clutch 13 is switched to the first transmission torque CL1, and the process proceeds to step ST4. In step ST4, the engine speed is compared with a predetermined value R1. The engine speed can be obtained from the output of the engine speed sensor 33, for example. When the engine 11 is started, the engine speed increases.

  If it is determined in step ST4 that the engine speed has exceeded the predetermined value R1 ("YES" in step ST4), the process proceeds to step ST5. If the engine speed does not exceed the predetermined value R1 (“NO” in step ST4), the process returns to step ST3 and the engine 11 is started.

  In step ST5, the clutch 13 is switched to the second transmission torque CL2. As described above, the second transmission torque CL2 has a smaller value than the first transmission torque CL1 and is set to a torque transmission rate that allows the rotation of the engine 11 to be maintained. Can be distributed to the power transmission mechanism 17 for rotating the wheel 18.

  If it is determined in step ST6 that the start has been completed ("YES" in step ST6), the process proceeds to step ST7. If the start is not finished (“NO” in step ST6), the process returns to step ST5, and the rotation of the engine 11 is maintained under the second transmission torque CL2.

  In step ST7, the clutch 13 is switched to the third transmission torque CL3. The third transmission torque CL3 has a torque transmission rate of substantially 100%, that is, a clutch directly connected state, whereby the output torque of the engine 11 is transmitted to the wheels 18 via the clutch 13, the motor 12, and the power transmission mechanism 17. It is transmitted.

Next, “(2) Low opening high vehicle speed start mode” will be described.
In step ST8, the vehicle speed is compared with a predetermined value S1. The vehicle speed can be obtained by the output of the vehicle speed sensor 32, for example. If it is determined that the vehicle speed exceeds the predetermined value S1 ("YES" in step ST8), the process proceeds to step ST9, where "(2) low opening high vehicle speed start mode" is executed. If the vehicle speed does not exceed the predetermined value S1 ("NO" in step ST8), the process proceeds to step ST13.

  Steps ST9 to ST12 correspond to “(2) Low opening high vehicle speed start mode” described in FIG. In step ST9, the clutch 13 is switched to the fourth transmission torque CL4 to start the engine 11, and the process proceeds to step ST10. Since the fourth transmission torque CL4 has a smaller torque transmission rate than the first transmission torque CL1, the start-up rises more slowly than when starting with the first transmission torque CL1. It can be suppressed.

  In step ST10, the engine speed is compared with a predetermined value R1. When the engine 11 is started, the engine speed increases. If it is determined in step ST10 that the engine speed exceeds the predetermined value R1 ("YES" in step ST10), the process proceeds to step ST11. If the engine speed does not exceed the predetermined value R1 (“NO” in step ST10), the process returns to step ST9 and the engine 11 is started under the fourth transmission torque CL4.

  In step ST11, the clutch 13 is switched to the fifth transmission torque CL5. The fifth transmission torque CL5 is smaller in value than the first transmission torque CL1 and is set to a torque transmission rate that can maintain the rotation of the engine 11. Therefore, most of the output torque of the motor 12 is supplied to the wheels 18. The power can be distributed to the power transmission mechanism 17 for rotation. The fifth transmission torque CL5 may be the same value as or different from the second transmission torque CL2 described in “(1) High opening start mode”.

  If it is determined in step ST12 that the start has been completed ("YES" in step ST12), the process proceeds to step ST7. In step ST7, the clutch 13 is switched to the third transmission torque CL3 (clutch direct connection). As a result, the output torque of the engine 11 is transmitted to the wheels 18 via the clutch 13, the motor 12 and the power transmission mechanism 17. If the start is not completed (“NO” in step ST12), the process returns to step ST11, and the rotation of the engine 11 is maintained under the fifth transmission torque CL5.

Next, “(3) Low opening low vehicle speed start mode” will be described.
In step ST8, when the vehicle speed does not exceed the predetermined value S1 ("NO" in step ST8), the process proceeds to step ST13. In step ST13, the clutch 13 is switched to the sixth transmission torque CL6. Since the torque transmission rate of the sixth transmission torque CL6 is smaller than that of the first transmission torque CL1, the start-up rise is slower than when starting with the first transmission torque CL1. It can be suppressed. The sixth transmission torque CL6 may be the same value as or different from the fourth transmission torque CL4 described in “(2) Low opening high vehicle speed start mode”.

  If it is determined in step ST14 that the start has been completed ("YES" in step ST14), the process proceeds to step ST7. In step ST7, the clutch 13 is switched to the third transmission torque CL3 (clutch direct connection). As a result, the output torque of the engine 11 is transmitted to the wheels 18 via the clutch 13, the motor 12 and the power transmission mechanism 17. If the start is not completed (“NO” in step ST14), the process returns to step ST13, and the rotation of the engine 11 is increased under the sixth transmission torque CL6.

  As described above, according to the present embodiment, when a request for starting the engine 11 is issued during traveling by the motor 12, a plurality of types of start control are performed according to the accelerator opening and the vehicle speed. For example, in the “(1) high opening start mode”, the engine 13 is started in a short time by setting the clutch 13 to the first transmission torque CL1, and when the accelerator pedal 30 is depressed, Since the torque rises quickly, the responsiveness is improved. When the engine speed exceeds the predetermined value R1, the motor output torque that can maintain the rotation of the engine 11 is transmitted to the engine 11 by switching to the second transmission torque CL2. The driving torque for rotating the wheels 18 can be distributed. This is advantageous for a motor having a relatively small output.

  In the “(2) low opening high vehicle speed start mode”, the clutch 13 is set to the fourth transmission torque CL4, so that the shock when the clutch is engaged is small and the engine speed exceeds the predetermined value R1. By switching to the transmission torque CL5 of 5, most of the motor output torque can be distributed to the drive torque for rotating the wheels 18. In the “(3) low opening low vehicle speed start mode”, the engine 11 is started by the sixth transmission torque CL6, and after the start, the engine 11 and the motor 12 can be directly connected.

  The superordinate concept of the torque switching means includes a high vehicle speed start mode that is executed when the vehicle speed exceeds the predetermined value S1 regardless of the accelerator opening. In the high vehicle speed start mode, for example, as shown in steps ST8 to ST12 in FIG. 5, the engine 11 is started by switching the clutch 13 to the fourth transmission torque CL4, and the engine speed exceeds a predetermined value R1. And the clutch (13) is switched to the fifth transmission torque CL5 having a torque transmission rate smaller than that of the fourth transmission torque CL4, and when the end of the start is determined, the clutch 11 is switched to the fourth and fifth transmission torques CL4 and CL5. Means for switching to a larger third transmission torque CL3.

  In implementing the present invention, it goes without saying that the specific elements constituting the engine start control device can be variously changed, including the configuration and arrangement of the engine, motor and clutch or various sensors mounted on the hybrid vehicle. Yes. For example, the clutch may employ various types of clutches according to vehicle specifications, such as a wet multi-plate clutch, a dry clutch, a fluid clutch, and a magnet clutch using magnetic force.

  DESCRIPTION OF SYMBOLS 10 ... Hybrid vehicle, 11 ... Engine, 12 ... Motor, 13 ... Clutch, 20 ... Control part, 23 ... ECU, 31 ... Accelerator sensor (means to detect accelerator opening), 32 ... Vehicle speed sensor (vehicle speed detection means), 33 ... Engine speed sensor (rotation speed detecting means), CL1 ... First transmission torque, CL2 ... Second transmission torque, CL3 ... Third transmission torque, CL4 ... Fourth transmission torque, CL5 ... Fifth Transmission torque, CL6 ... Sixth transmission torque.

Claims (8)

An engine start control device for a hybrid vehicle in which a clutch is disposed between a traveling engine and a motor,
Means for detecting the accelerator opening;
Means for detecting the vehicle speed;
Means for determining the presence or absence of an engine start request;
Torque switching means for switching the transmission torque of the clutch according to the accelerator opening and the vehicle speed when there is a request to start the engine while the vehicle is running by a motor;
An engine start control device for a hybrid vehicle, comprising: Means for detecting the engine speed;
The torque switching means is
Including a high opening start mode executed when the accelerator opening exceeds a predetermined value,
The high opening start mode is:
Starting the engine by switching the clutch to the first transmission torque;
When the engine speed exceeds a predetermined value, the clutch is switched to a second transmission torque having a torque transmission rate smaller than the first transmission torque,
2. The engine start control for a hybrid vehicle according to claim 1, further comprising means for switching the clutch to a third transmission torque larger than the first and second transmission torques when it is determined that the start is finished. apparatus. The torque switching means is
A low opening high vehicle speed start mode executed when the accelerator opening does not exceed a predetermined value and the vehicle speed exceeds a predetermined value;
A low opening low vehicle speed start mode executed when the accelerator opening does not exceed a predetermined value and the vehicle speed does not exceed a predetermined value,
The low opening high vehicle speed start mode is:
The engine is started by switching the clutch to a fourth transmission torque having a torque transmission rate smaller than the first transmission torque and a torque transmission rate larger than the second transmission torque;
When the engine speed exceeds a predetermined value, the clutch is switched to a fifth transmission torque having a torque transmission rate smaller than the fourth transmission torque,
Means for switching the clutch to the third transmission torque when it is determined that the start has been completed;
The low opening low vehicle speed start mode is:
The engine is started by switching the clutch to a sixth transmission torque having a torque transmission rate smaller than the first transmission torque and a torque transmission rate larger than the second transmission torque;
3. The engine start control device for a hybrid vehicle according to claim 2, further comprising means for switching the clutch to the third transmission torque when it is determined that the start is finished.   4. The engine start control device for a hybrid vehicle according to claim 2, wherein the third transmission torque is a transmission torque having a torque transmission rate of 100% that directly connects the engine and the motor. 5.   5. The hybrid according to claim 3, wherein the second transmission torque in the high opening start mode and the fifth transmission torque in the low opening high vehicle speed start mode are equal to each other. Vehicle engine start control device.   The second transmission torque in the high opening start mode has a torque transmission rate smaller than that of the fifth transmission torque in the low opening high vehicle speed start mode. An engine start control device for a hybrid vehicle.   The fourth transmission torque in the low opening high vehicle speed start mode and the sixth transmission torque in the low opening low vehicle speed start mode are equal to each other. The engine start control device for a hybrid vehicle according to the item. Means for detecting the engine speed;
The torque switching means is
Including a high vehicle speed start mode executed when the vehicle speed exceeds a predetermined value;
The high vehicle speed start mode is:
Starting the engine by switching the clutch to the fourth transmission torque;
When the engine speed exceeds a predetermined value, the clutch is switched to a fifth transmission torque having a torque transmission rate smaller than the fourth transmission torque,
2. The engine start control of a hybrid vehicle according to claim 1, further comprising means for switching the clutch to a third transmission torque larger than the fourth and fifth transmission torques when it is determined that the start is finished. apparatus.

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