JP2001140674A - Engine starting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decide whether seizure of a clutch is generated or not in a constitution that a starter motor is coupled with an engine via the clutch. SOLUTION: An engine 10 is coupled with a starter motor 14 via a one way clutch 15. The starter motor 14 is a synchronous motor and is controlled in rotation by a control unit 60. An actual number of revolution of the starter motor 14 is periodically monitored by a number of revolution sensor 17. When the actual number of revolution remarkably exceeds a number of revolution command value when the control unit 60 controls the starter motor 14, seizure of the one way clutch 15 is judged and engine speed of the engine 10 is suppressed. As a result, abnormal high speed rotation of the starter motor 14 due to co-rotation by the engine 10 by seizure of the clutch 15 can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for judging whether the coupling mechanism is stuck in an engine starting device that starts an engine using an electric motor coupled to the engine via a clutch or other coupling mechanism.

[0002]

2. Description of the Related Art In recent years, hybrid vehicles using an engine and an electric motor as power sources have been proposed. In a hybrid vehicle, in addition to stopping the engine while the vehicle is stopped, the hybrid vehicle can be driven with the engine stopped using an electric motor as a power source. In addition, in a normal vehicle using only an engine as a power source, control for stopping the engine while the vehicle is stopped has been proposed in order to improve fuel efficiency. As described above, in recent years, various technologies have been proposed in which the engine is frequently stopped and started during the operation of the vehicle.

[0003] Auxiliary equipment such as air conditioners and power steering oil pumps are usually driven by an engine. Therefore, when the engine is stopped during operation of the vehicle, these auxiliary equipment are provided by another means while the engine is stopped. Need to be driven. As a method for realizing this driving, for example, a technique including an accessory driving motor for driving the accessory has been proposed (for example, a technique described in Japanese Patent Application Laid-Open No. H10-339185). In this technique, a motor capable of driving an auxiliary machine via a belt transmission mechanism is connected to a crankshaft of an engine via a clutch. While the engine is stopped, the clutch is released, the motor is run, and the accessory is driven. When the clutch is engaged, the engine can be cranked by the power of the motor and the engine can be started.

[0004]

However, during operation of the vehicle, there is a possibility that the clutch connecting the engine and the auxiliary drive motor may seize for some reason. Alternatively, there is a possibility that the clutch cannot be released due to entry of foreign matter. If the clutch sticks due to seizure or the like, the auxiliary drive motor is always connected to the engine,
It is in a state where it can be rotated with the rotation of the engine. Therefore, when the engine rotates at a high speed, the accessory drive motor is rotated at a rotation speed exceeding an allowable range, and the life of the motor may be significantly shortened.

[0005] The problem is that the motor for starting the engine is driven by a clutch or the like regardless of whether control to stop the engine is performed during operation and whether or not the motor is used to drive auxiliary equipment. This is a problem common to vehicles coupled via the coupling mechanism. In other words, even in a conventional vehicle in which the engine is started by a so-called cell motor, the same problem may occur if the mechanism for coupling and releasing the cell motor to and from the engine is fixed and constantly engaged. However, for vehicles that may stop the engine while driving,
Since there is a high demand for a smooth start of the engine, motors capable of accurately controlling the rotation are often used for starting the engine, and these motors usually have a relatively low range of allowable rotation speed. For this reason, the above-mentioned problem has not been particularly overlooked. The present invention has been made in order to solve these problems, and in a configuration in which a motor for starting an engine is coupled to an engine via a clutch or another coupling mechanism, a technique for avoiding adverse effects due to fixation of the coupling mechanism. The purpose is to provide.

[0006]

Means for Solving the Problems and Their Functions and Effects In order to solve at least a part of the above problems, the present invention employs the following constitution. The present invention provides an electric motor coupled to an engine via a coupling mechanism capable of coupling and detaching two rotating shafts, and a start control for engaging the coupling mechanism and powering the electric motor to rotate the engine. An engine starting device comprising: a detection unit configured to detect a predetermined parameter corresponding to an actual rotation speed of the electric motor; and detecting whether the rotation state of the electric motor is a predetermined target rotation state by detecting the parameter. A gist comprising: a determination unit that determines based on a result; and an output unit that outputs a signal that prompts a predetermined operation for suppressing the actual rotation speed to the outside when it is determined that the target rotation state is deviated. I do.

It is generally difficult to determine whether the coupling mechanism is stuck due to seizure or the like, but in the present invention, this determination is relatively easily realized by the above configuration. That is, in a state where the coupling mechanism is not fixed, the actual rotation speed of the electric motor is generally maintained at the target rotation state. Therefore, by detecting the actual rotation speed through some parameter, the coupling machine can be operated. It can be determined whether or not it is fixed. As the parameter, the rotation speed itself may be used, or when a permanent magnet type motor is provided, an induced electromotive voltage generated by rotation of the motor or a current flowing by the electromotive voltage may be used as the parameter. When it is determined that the coupling mechanism is stuck, the electric motor is forcibly rotated together with the engine, so that the engine starting device itself cannot suppress the rotation, but according to the above configuration, By outputting a signal to the outside, it is possible to promote suppression of the actual rotation speed.

[0008] In the engine starter of the present invention, the determination means may have various configurations. For example, the determination means determines whether or not the actual rotation speed exceeds an upper limit value of the rotation speed allowed for the electric motor. The means may be a means for making the determination based on the determination. In this case, the above-mentioned predetermined target rotation state is a range that does not exceed the upper limit value of the permitted number of rotations. The allowable upper limit of the number of revolutions can be set in consideration of both the mechanical upper limit and the electrical upper limit. The electric upper limit value is, for example, when the electric motor is a permanent magnet type synchronous motor driven by a drive circuit, a current flowing through the drive circuit due to an induced electromotive voltage generated by the electric motor is equal to or less than an allowable value. The number of rotations set in the range can be set.

[0009] Further, the determination means is a means for making the determination based on whether or not the actual rotation speed is greater than a rotation speed command value specified by the start control device by a predetermined value or more. It may be a thing. When the electric motor is operated under the control of the start control device, the rotation speed of the motor should fall within a predetermined range in consideration of the fluctuation due to the control from the rotation speed command value. Therefore, by setting such a range as the target rotation state, it is possible to determine whether or not the electric motor is forcibly rotated outside the control of the start control device, that is, whether or not the coupling mechanism is fixed. it can.
The determination in this case is performed based on, for example, whether a value obtained by subtracting the rotation speed command value from the actual rotation speed is equal to or greater than a predetermined value, and the ratio between the actual rotation speed and the rotation speed command value is equal to or greater than a predetermined value. It is possible to adopt an aspect in which the determination is made based on whether or not.
Of course, it goes without saying that various arithmetic expressions equivalent to these can be applied.

[0010] Here, the rotation speed command value in a narrow sense means a target value at the time of power running of the motor, but in a broad sense also includes a value when the motor is stopped. If the start controller does not instruct powering of the motor, the motor speed should be zero. Therefore, the determination means includes a mode in which this value is regarded as a rotation speed command value and a determination is made based on whether or not a deviation from the actual rotation speed is larger than a predetermined range.

The present invention is particularly effective when the rotation speed allowed for the electric motor is relatively low. For example, it is effective when the number of rotations when the motor is forcibly rotated by rotating the engine at a high speed with the coupling mechanism stuck exceeds the upper limit of the allowable number of rotations of the motor including the drive circuit. . Further, the present invention is particularly effective when the operation of a system equipped with an engine is greatly affected, for example, when the motor is rotated in an inappropriate state and its life is significantly shortened. From this point of view, it is desirable that the present invention be applied to an engine starter including a motor and a start control device configured to control the number of revolutions relatively accurately. It is also desirable to apply the present invention to a system in which the electric motor is used not only for starting the engine but also for driving auxiliary machines and other purposes. A specific example of such a system includes a vehicle equipped with the above-described engine.

In the present invention, the coupling mechanism may employ various configurations, but is preferably a one-way clutch capable of transmitting torque only from the electric motor to the engine. When a one-way clutch is applied, there is an advantage that the engine can be started by the electric motor without controlling engagement and disengagement of the coupling mechanism. Further, since the one-way clutch is more likely to be stuck than other coupling mechanisms, the present invention can be effectively used. The coupling mechanism according to the present invention includes the above-described one-way clutch, multi-plate clutch,
Various types of clutch mechanisms such as electromagnetic clutch
Includes general mechanisms that can engage and disengage shaft power transmission.
For example, a mechanism in which a gear is fixed to each of two shafts and one of the gears is movable in the axial direction to engage or disengage the two with each other is also included in the coupling mechanism of the present invention.

In the present invention, the signal output by the output means is, for example, a signal for suppressing the number of revolutions of the engine, or a signal notifying that the rotation state of the electric motor deviates from a target rotation state. Or something. When the former signal is output, the engine control device that controls the operation of the engine includes a rotation speed suppression control unit that suppresses the rotation speed of the engine in accordance with the signal, thereby reducing the rotation speed of the engine. As a result, the number of rotations of the electric motor can be suppressed. In this case, the engine starter may directly output the engine speed command value,
When repeatedly determining whether or not the rotation state of the electric motor is in the target state, a signal may be output that simply prompts further suppression of the engine speed in accordance with the determination result. In the case of outputting the latter signal, the driver that has detected the notification can suppress or stop the engine speed, thereby suppressing the motor speed.

In the engine starter of the present invention, when the electric motor is a permanent magnet type synchronous motor driven by a drive circuit, and when it is determined that the rotation is out of the target rotation state, the inverter is connected to the inverter. It is also preferable to provide a current control unit for controlling the electric current to flow a current for suppressing the magnetic field generated by the permanent magnet to the electric motor.

In a permanent magnet type synchronous motor, the upper limit of the allowable number of rotations is often determined based on an induced electromotive voltage generated when the motor rotates. This is because when the number of rotations increases, the induced electromotive voltage increases, and the current flowing through the drive circuit exceeds an allowable range. In such a case, it is necessary to suppress the number of revolutions of the engine to such a degree that the current due to the induced electromotive voltage falls within an allowable range, but this limits the operating range of the system equipped with the engine. For example, when the engine is mounted on a vehicle, adverse effects such as a severe limitation of the traveling speed are caused. When the above configuration is applied, the magnetic field generated by the permanent magnet can be suppressed, so that the induced electromotive voltage can be suppressed. Therefore, the allowable rotation speed of the electric motor when the coupling mechanism is fixed can be increased, and the adverse effect caused by the induced electromotive voltage can be reduced. The method of flowing a current for suppressing the magnetic field by the permanent magnet may be, for example, a method in which a voltage is applied to the d-axis, or a method in which the voltage application direction when driving the electric motor is shifted by a predetermined angle. .

The present invention can be configured as a drive system including the engine starter, in addition to the above-described engine starter. An engine starter comprising: an electric motor coupled to an engine via a coupling mechanism; and a start control device for rotating the engine by powering the electric motor while engaging the coupling mechanism. It can also be configured as a sticking determination method for determining sticking of.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in the following order based on examples. A. Device configuration: General operation: Clutch sticking determination processing: First modified example: Second modified example: Other variations:

A. Device Configuration: FIG. 1 is an explanatory diagram showing a schematic configuration of a power system of a hybrid vehicle as an embodiment. The hybrid vehicle of the embodiment includes an engine 10, a planetary gear 30, a motor 20, and a continuously variable transmission (hereinafter, referred to as CVT) 40 as main mechanisms for outputting power. The engine 10 is a gasoline engine. The motor 20 is a three-phase synchronous motor in which a permanent magnet is attached to a rotor.
1 (hereinafter referred to as a power running operation). When the motor 20 is rotated by an external force, the motor 20 functions as a generator, and the obtained power can be charged in the battery 22 (hereinafter, such an operation state is referred to as a regenerative operation).

The planetary gear 30 includes a sun gear 31 that rotates at the center, pinion gears 32a and 32b that revolve while rotating around the sun gear 31, and these pinion gears 32.
A planetary carrier 33 which is rotatably supported by a shaft 33, and a ring gear 36 which is further rotatable around the pinion gear 32b
, A so-called double pinion type planetary gear. The planetary gear 30 includes a sun gear 31,
It is known that the rotational speed and the torque of the planetary carrier 33 and the ring gear 36 are represented by the following relational expressions. Ns = (1 + ρ) / ρ × Nc−Nr / ρ; Nc = ρ / (1 + ρ) × Ns + Nr / (1 + ρ); Nr = (1 + ρ) Nc−ρNs; Ts = Tc × ρ / (1 + ρ) = ρTr; Tr = Tc / (1 + ρ); ρ = number of teeth of sun gear / number of teeth of ring gear;

Here, Ns is the number of revolutions of the sun gear 31;
s is the torque of the sun gear 31; Nc is the rotation speed of the planetary carrier 33; Tc is the torque of the planetary carrier 33; Nr is the rotation speed of the ring gear 36;

The CVT 40 has a configuration in which a belt 43 is hung between two pulleys 41 and 42. Pulley 4
The width of each of the reference numerals 1 and 42 is variable by a hydraulic mechanism (not shown). When the widths of the pulleys 41 and 42 are continuously changed, the effective radius of the portion of the belt 43 that is hooked on the pulleys 41 and 42 is continuously changed, so that the reduction ratio of the power transmission can be changed to an unrestricted floor.

The connected state of the engine 10, the planetary gear 30, the motor 20, and the CVT 40 is as follows. The crankshaft 11 is connected to a sun gear 31. The motor 20 is connected to a planetary carrier 33.
Rotary plates 35 and 39 for inputting power are coupled to the pulley 41 of the CVT 40, and the planetary carrier 33 is configured to be coupled to and decoupled from the rotary plate 35 via a first clutch 34. Ring gear 36
Is configured to be connectable to and disconnectable from the rotary plate 39 via the second clutch 38. The ring gear 36 is also provided with a brake 37 for stopping its rotation. A drive shaft 50 capable of transmitting power via a differential gear 51 is connected to an axle 52 to which wheels 53 are connected, to a pulley 42 of the CVT 40. By switching the engagement states of the clutches 34 and 38 and the brake 37, the hybrid vehicle of the present embodiment can input the power from the engine 10 and the motor 20 to the CVT 40 in various modes described later, and Can be output to

In the hybrid vehicle of the embodiment, in addition to the system for outputting power, a mechanism for starting the engine 10,
Further, a mechanism for driving the auxiliary machine 12 is provided. The accessory 12 includes an air conditioner, an oil pump, and the like. The accessory 12 is connected to the engine 10 and the starter motor 14 by a transmission mechanism using a belt 13. The starter motor 14 is a three-phase synchronous motor in which a permanent magnet is attached to a rotor, and is connected via a one-way clutch 15 that transmits power only in the direction of the belt 13 from the motor side. By switching the inverter 16, the starter motor 1 is powered by the battery 22.
4, the engine 10 can be cranked and started by the power. Starter motor 1
Reference numeral 4 denotes a synchronous motor, which is capable of controlling the rotation speed with high precision, so that the rotation speed of the engine 10 can be smoothly increased and a smooth start can be realized. on the other hand,
When the engine 10 is operating, the motive power of the accessory 12 is transmitted by a transmission mechanism and driven. When the operation of the engine 10 is stopped,
When it is necessary to drive the auxiliary machine 12, the starter motor 14 is powered and the power is used to drive the auxiliary machine 12. At this time, the engine 10 is idled.

The configuration of the inverter 16 serving as a drive circuit for the starter motor 14 will be described. FIG. 2 is a circuit diagram of the inverter. Inverter 16 is configured as a transistor inverter. U of the starter motor 14,
In the V and W phases, a total of six transistors (Tu +, Tu−, Tv +, Tv−, Tw +, Tw +,
Tw-) is provided. Each transistor has a flywheel diode (Du +, Du−, Dv +, Dv +).
−, Dw +, Dw−). These transistors include switching control signals VU, VV,
VW is input from the control unit 60. The control signal input for each phase is inverted high / low by the inverters INU, INV, INW with respect to the transistor on the sink side and then input. Therefore, the transistors on the source side and the sink side are switched so that one is high and the other is low. When each transistor of the inverter 16 is so-called PWM controlled, the pseudo three-phase alternating current becomes U,
The flow starts in the V and W phases, and the starter motor 14 rotates. In addition,
Although a shutdown signal for turning off all the transistors is also input from the control unit 60 to the inverter 16, it is not shown here. The inverter 21 that drives the motor 20 has the same configuration as the inverter 16, and is PWM-controlled by a control signal from the control unit 60.

The control unit 60 includes a CPU, RA
It is configured as a microcomputer including M and ROM, and plays a role of comprehensively controlling the power system of the embodiment including the inverters 16 and 21. In FIG. 1, signals exchanged with the control unit 60 are indicated by broken lines. The control unit 60 controls the engine 10, the clutches 34 and 3 in addition to the inverters 16 and 21.
8, brake 37 and CVT40. In order to realize these controls, signals from various sensors are input to the control unit 60. In FIG. 1, the rotation speed sensor 17 of the starter motor 14 is related to the control described later.
, And only other signals from the sensor are not shown.

B. General Operation: Next, a general operation regarding the output of power in the hybrid vehicle of the present embodiment will be described. FIG. 3 shows the clutch 3 in each operation mode.
FIG. 4 is an explanatory diagram showing engagement states of the brakes 4, 38 and a brake 37. These engagement states are switched according to the operation of the shift lever by the driver, the vehicle speed, the state of charge of the battery 22, and the like. When the shift lever is in a forward shift position called a B range or a D range, three types of operation modes of an electric torque converter (ETC) mode, a direct connection mode, and a motor traveling mode can be selected.
In the ETC mode, the first clutch 34 and the brake 37 are disengaged, and the second clutch 38 is engaged.
At this time, the rotation speed and the torque of the ring gear 36 are determined according to the rotation speed and the torque of the engine 10 connected to the sun gear 31 and the motor 20 connected to the planetary carrier 33, as is clear from the above-described relational expression. You. Therefore, by controlling the rotation speed of the motor 20 while operating the engine 10 at a constant rotation speed and torque, the rotation speed of the ring gear 36 can be changed smoothly.
Smooth acceleration of the vehicle can be realized. Note that E
The operation state of the motor 20 in the TC mode is a regenerative operation.

In the direct connection mode, the clutches 34 and 38 are engaged, and the brake 37 is disengaged. At this time, as is apparent from the above-mentioned relational expression, the planetary gear 30 rotates integrally, so that the power of the engine 10 is directly transmitted to the CVT 40. At the same time, the power of the engine 10 can be assisted by running the motor 20 or a part of the power of the engine 10 can be regenerated by the motor 20.

In the motor running mode, the first clutch 3
4, only the second clutch 38, the brake 37
Is disengaged. At this time, the motor 20 is connected to the CVT 40. In the state where the second clutch 38 and the brake 37 are released, the rotation state of the ring gear 36 is not determined, and the rotation state of the planetary gear 30 is not determined, which is equivalent to the engine 10 being substantially disconnected.

When the shift lever is in the N range or the P range, a neutral mode or a charging or engine starting mode can be selected. In the neutral mode, all of the clutches 34 and 38 and the brake 37 are disengaged. At this time, power cannot be transmitted to the CVT 40 at all. In the charging and engine start mode, only the brake 37 is engaged, and the clutches 34 and 38 are disengaged. Since the clutches 34 and 38 are disengaged,
Although power is not transmitted to the CVT 40, the rotation state of the planetary gear 30 can be determined by engaging the brake 37. Therefore, the power of the engine 10 can be regenerated by the motor 20, or conversely, the motor 20 can be powered to motor the engine 10.

When the shift lever is in the R range, a motor traveling mode and a friction traveling mode can be selected. In the motor drive mode, the first clutch 34
Only the second clutch 38 and the brake 37 are disengaged. At this time, the motor 20 is connected to the CVT 40. In the friction running mode, the first clutch 34 is engaged, the second clutch 38 is disengaged, and the brake 37 is slip-engaged. This makes it possible to move backward using the power of the motor 20 and the engine 10.

The hybrid vehicle of this embodiment travels by using these operation modes properly. The description will be made by taking the case of moving forward as an example. First, the operation of the engine 10 is stopped during a stop, including a temporary stop such as waiting for a traffic light. As described above, during this time, the auxiliary machine 12 is driven by powering the starter motor 14. When the driver depresses the accelerator pedal to perform an acceleration operation, fuel is supplied to the engine 10 that has been cranked by the starter motor 14, and the engine 10 starts operating. And ETC
By adjusting the regenerative electric power of the motor 20 in the mode, the output is started while changing the rotation speed of the engine 10 smoothly, and the engine 10 starts and accelerates. In the motor running mode, the motor 20
In some cases, the vehicle starts using only the power of the vehicle. Even when the vehicle starts in the motor running mode, the engine 10 is cranked by the starter motor 14, so that fuel is supplied and the engine 10 is started when a predetermined speed is reached. Thereafter, in a running state where the power of the engine 10 needs to be shifted only by the CVT 40,
When the direct connection mode is selected and the shift is required beyond the shift range of the CVT 40, the ETC mode is selected and the vehicle travels.

C. Clutch seizure determination processing: As described above, the hybrid vehicle according to the present embodiment drives the auxiliary machine 12 using the starter motor 14 coupled via the one-way clutch 15 or starts the engine 10 to travel. I do. During the operation of the engine 10, power is not transmitted from the belt 13 to the starter motor 14 by the action of the one-way clutch 15, so that the starter motor 1
4 is not forced to rotate. However, when the one-way clutch 15 is seized, the engine 10
Is transmitted to the starter motor 14, the starter motor 14 may be forcibly rotated. In this embodiment, since a permanent magnet type synchronous motor is used as the starter motor 14, an induced electromotive force is generated in each phase when the synchronous motor is forcibly rotated. There is a possibility that a large amount of current will flow through 16. As shown in FIG. 2, in the inverter 16, a flywheel diode is provided for each transistor, so that the induced current flows even when all the transistors are turned off. In the hybrid vehicle according to the present embodiment, in order to avoid such an adverse effect due to an unexpectedly large current, the process of determining whether the clutch is seized is periodically performed together with the operation control.

The concept of the clutch sticking determination process is as follows. In this embodiment, since the starter motor 14 is connected to the engine 10 via the one-way clutch 15, the starter motor 14 should rotate under the control of the control unit 60 unless the one-way clutch 15 is burned. However, when the one-way clutch 15 is seized, the actual rotation speed of the starter motor 14 is greatly deviated from the rotation speed command value instructed by the control unit 60 due to the power of the engine 10. Focusing on this point, in the present embodiment, the seizure of the one-way clutch 15 is determined based on whether or not the actual rotation speed of the starter motor 14 is greatly deviated from the rotation speed command value. When the seizure of the clutch is detected, the number of revolutions of the engine 10 is limited to avoid the above-described adverse effects.

A flowchart for realizing the above processing will be described. FIG. 4 is a flowchart of the clutch sticking determination process. This is a process that is periodically performed by the CPU of the control unit 60 together with other control processes. When this process is started, the CPU inputs the rotation speed command value Ns * and the actual rotation speed Ns of the starter motor 14 (step S1).
0). The rotation speed command value Ns * is a value set by the CPU when the CPU controls the operation of the starter motor 14 in another routine. The actual rotation speed Ns is a value detected by the rotation speed sensor 17.

Next, the actual rotation speed Ns and the rotation speed command value Ns *
Then, it is determined whether or not the deviation from is larger than a predetermined value Drm (step S12). The predetermined value Drm is set based on a fluctuation range of the number of rotations that may be caused by an error during control. If the value exceeds the value Drm, it is determined that the one-way clutch 15 may be seized. However, in the present embodiment, in order to avoid erroneous determination that the clutch is seized due to instantaneous occurrence of vibrations during running, irregular fluctuations in the actual rotation speed, and the like, the state where the value exceeds the value Drm is constant. It is determined that the one-way clutch 15 is seized in the case where the error occurs continuously during the period.

This determination is made using a parameter td representing the duration of the state exceeding the value Drm. Therefore, in step S12, when it is determined that the deviation is larger than the value Drm, the parameter td is increased by the value ts (step S16), and when it is determined that the deviation is smaller than the value Drm, the parameter td is increased. The value is reset to 0 (step S14). The value ts is the elapsed time from the previous execution of the clutch burn-in determination process to the present, and is usually a constant value.

When the parameter td is reset to the value 0, the clutch burn-in determination routine ends without performing any subsequent processing. On the other hand, when the parameter td is increased, it is determined whether or not the result exceeds a predetermined value tth (step S18). The predetermined value tth is a value that can be arbitrarily set as a duration that can be determined that the one-way clutch 15 is seized. In this embodiment, it is set to 10 seconds. If the value tth is set to be long, it is possible to suppress erroneous determination regarding the seizure of the clutch. However, if the seizure of the clutch occurs, the starter motor 14 is rotated for a long time in that state. Occurs. Therefore, the value tth
Is preferably set to an appropriate value in consideration of both the accuracy of burn-in determination and the avoidance of adverse effects when burn-in occurs.

In step S18, the parameter td
Is less than or equal to the value tth, the one-way clutch 1
Since it cannot be determined that 5 is burned in, the clutch burn-in determination routine ends without performing any processing. On the other hand, if the value exceeds the value tth, it is determined that the one-way clutch 15 is seized, so that a process of limiting the rotational speed of the engine 10 to suppress the rotational speed of the starter motor 14 is executed (step S20). ).
Here, a process of turning on a flag for limiting the rotation speed of the engine 10 is performed. Actually, when this flag is turned on, the rotational speed of the engine 10 is suppressed by a routine separately executed to control the operation of the engine 10.

The target value for limiting the number of revolutions of the engine 10 may be set according to the number of revolutions permitted for the starter motor 14. That is, based on the upper limit value of the rotational speed mechanically permitted for the starter motor 14 (hereinafter referred to as the mechanical upper limit) and the allowable range of the current flowing through the inverter 16 when the induced electromotive voltage is generated in the starter motor 14. The rotational speed of the engine 10 may be limited to a range that does not exceed the lower limit of the determined upper limit of the rotational speed (hereinafter referred to as an electrical upper limit). In this embodiment, the upper limit rotation speed of the starter motor 14 is approximately 7000 rpm due to the electrical upper limit.
m, the rotational speed limit of the engine 10 is set so that the rotational speed of the starter motor 14 falls within such a range.
Here, since the engine 10 and the starter motor 14 are connected via a transmission mechanism by the belt 13, it is necessary to set the limit rotation speed of the engine 10 in consideration of the gear ratio in the transmission mechanism.

According to the hybrid vehicle of the present embodiment described above, the drive of the auxiliary machine 12 and the smooth start of the engine 10 can be realized by the starter motor 14 connected via the one-way clutch 15. At this time, whether or not the seizure of the one-way clutch 15 has occurred can be relatively easily determined without providing a special mechanism. Further, when it is determined that the clutch seizure has occurred, the number of revolutions of the engine 10 can be limited to avoid the adverse effect caused by the seizure.

D. First Modification: The determination of the seizure of the clutch can be realized by various processes other than the processes described in the embodiment. FIG. 5 is a flowchart of clutch burn-in determination processing as a first modification. In the embodiment, the process of determining the burn-in of the clutch based on the deviation between the rotation speed command value of the starter motor 14 and the actual rotation speed has been exemplified.
The first modification is different in that the seizure of the clutch is determined based on whether or not the actual rotation speed of the starter motor 14 exceeds the upper limit value of the allowable rotation speed.

In the process of the first modification, first, the actual rotation speed Ns of the starter motor 14 is input (step S3).
0). Then, the actual rotational speed Ns is compared with a predetermined value NMo (step S32), and the actual rotational speed Ns is compared with the predetermined value NMo.
If it exceeds r, the parameter td is increased by the value ts (step S36). If the actual rotational speed Ns is equal to or smaller than the predetermined value Nmor, the parameter td is reset (step S34), and the clutch burn-in determination processing ends without performing other processing. The contents of the parameter td and the value ts are the same as in the embodiment.

The predetermined value N Mor is set based on the lower one of the mechanical upper limit and the electrical upper limit described above. In the case of the hybrid vehicle of the embodiment, since the electric upper limit of the starter motor 14 is about 7000 rpm, the value N
Mor is set to a value slightly lower than 7000 rpm.

When the value of the parameter td is increased, the engine speed limiting process is executed when the value exceeds a predetermined value tth1 (steps S38 and S4).
0), while the value is equal to or less than the predetermined value tth1, the clutch burn-in determination processing ends without performing any processing. Value tth1
Is a continuation time serving as a criterion for judging that clutch seizure has occurred, as in the embodiment. In the first modified example, since the seizure of the clutch is determined by comparing with a predetermined value N Mor set based on the upper limit of the number of revolutions allowed for the starter motor 14, if the value tth1 is too large, the clutch There is a possibility that adverse effects due to image sticking may occur. Therefore, it is desirable that the value tth1 be as short as possible within a range where erroneous determination can be avoided. In the first modification, the value tth1 is set to 100 msec. The reason why the value N Mor is previously set to a value slightly lower than the upper limit of the rotation speed of the starter motor 14 is that the rotation speed of the starter motor 14 increases during the passage of the time tth1 due to the seizure of the clutch. This is to avoid occurrence. As described above, the value tth1 may be set based on the allowance of the value Nmor with respect to the allowable upper limit value of the rotation speed.

According to the processing of the first modified example, the burn-in of the clutch can be determined relatively easily as in the embodiment. Further, when it is determined that the clutch seizure has occurred, the number of revolutions of the engine 10 can be limited to avoid the adverse effect caused by the seizure. Also,
The first modified example also has an advantage that the adverse effect caused by the abnormally high rotation of the starter motor 14 can be reliably avoided even when the seizure of the clutch does not occur. In the first modified example, the case where the rotation speed N Mor as the reference for burn-in determination is set based on the upper limit rotation speed of the starter motor 14 has been described, but the rotation when the control unit controls the operation of the starter motor 14 is described. If an upper limit is set for the number command value, NMoR may be set based on the upper limit.

E. Second Modification: FIG. 6 is a flowchart of a clutch sticking determination process as a second modification.
In the second modified example, the method of determining whether or not clutch seizure has occurred is the same as in the embodiment (FIG. 4), but the processing content for avoiding the adverse effect due to clutch seizure is different from that of the embodiment.

That is, in the second modification, as in the embodiment, the seizure of the clutch is determined based on the deviation between the rotation speed command value Ns * of the starter motor 14 and the actual rotation speed Ns (steps S10 to S18). If it is determined that the seizure of the clutch has occurred, a process of applying a voltage to the d-axis of the starter motor 14 is performed together with a process of limiting the engine speed in order to avoid the adverse effects (step S20A).

Here, the significance of applying a voltage to the d-axis will be described. FIG. 7 is an explanatory diagram showing an equivalent circuit of the starter motor 14. Since the starter motor 14 is a permanent magnet type three-phase synchronous motor, it is represented by a permanent magnet rotating as a rotor and U, V, W phase coils arranged at equal angular intervals around the starter motor 14 as shown in the figure. You. In such an equivalent circuit, the direction of the magnetic field generated by the permanent magnet is defined as the d-axis, and the direction orthogonal thereto is defined as the q-axis. The position of the rotor is specified by the electrical angle θ between the d axis and the U phase.

When the starter motor 14 rotates, an induced electromotive voltage is generated in the U, V, and W phases by the magnetic field Md1 generated by the permanent magnet, and a current flows. As shown in the circuit diagram of FIG. 2, a flywheel diode is provided in each transistor of the inverter 16, so that even if all the transistors are shut down, a current due to the induced electromotive voltage flows. Since the induced electromotive voltage increases in accordance with the strength and rotation speed of the magnetic field Md1 generated by the permanent magnet, the induced electromotive voltage is suppressed by applying a current to the d axis so as to generate a magnetic field Md2 in a direction that cancels the magnetic field Md1 generated by the permanent magnet. The electric upper limit of the starter motor 14 can be increased. In step S20A of the second modification, a voltage is applied to the d-axis to obtain such an effect.

The actual control is performed by so-called vector control. That is, a voltage value to be applied in the d-axis direction is set in advance, and two-phase / three-phase conversion is performed in accordance with the electrical angle θ to convert into U, V, and W-phase voltage values. Voltage is applied by control. The powering of the starter motor 14 refers to a preset map based on the required torque and the number of rotations, and utilizes the fact that the current is set and controlled in the d-axis direction and the q-axis direction. Alternatively, the control may be performed by rotating the direction of the current obtained from this map by a predetermined angle in the d-axis direction.

According to the processing of the second modification, the electric upper limit of the starter motor 14 can be increased by applying a voltage to the d-axis. Accordingly, it is possible to increase the limit value of the rotation speed of engine 10 when seizure occurs in the clutch, and it is possible to improve the traveling speed of the hybrid vehicle. In the second modification, the case where the voltage is applied to the d-axis after judging the seizure of the clutch by the processing shown in the embodiment is illustrated. However, the seizure of the clutch is performed by the processing of the first modification (see FIG. 5). May be determined.

F. Other Modifications: The present invention can be applied to the following various modifications in addition to the above-described embodiments and modifications.

First, the present invention is not limited to a hybrid vehicle, but may be applied to a conventional vehicle using only the engine 10 as a power source. The present invention is applicable as long as the engine 10 and the starter motor 14 are connected via the one-way clutch 15 or another connecting mechanism. In such a case, the control processing described in the embodiment and the modification can be applied as it is. The above-described coupling mechanism includes a one-way clutch, a multi-plate clutch, an electromagnetic clutch, and other various mechanisms capable of coupling and disconnecting between two shafts.

Second, in place of the process for limiting the number of revolutions of the engine 10, a process for notifying the outside that the clutch seizure has occurred may be applied. As long as the means can be recognized by the driver, various notification means such as turning on a display and generating an alarm sound can be applied. If the driver recognizes that the clutch is seizing,
The operation of the engine 10 can be adjusted at the driver's discretion to avoid the adverse effects caused by burn-in.

Although various embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it goes without saying that various configurations can be adopted without departing from the spirit of the present invention. For example, the above-described control processing may be realized by software or by hardware. The starter motor 14 is not limited to a synchronous motor, and various AC motors and DC motors can be applied.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a power system of a hybrid vehicle as an embodiment.

FIG. 2 is a circuit diagram of an inverter.

FIG. 3 is an explanatory diagram showing engagement states of clutches 34 and 38 and a brake 37 in each operation mode.

FIG. 4 is a flowchart of a clutch sticking determination process.

FIG. 5 is a flowchart of clutch burn-in determination processing as a first modified example.

FIG. 6 is a flowchart of clutch burn-in determination processing as a second modification.

FIG. 7 is an explanatory diagram showing an equivalent circuit of a starter motor 14.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Engine 11 ... Crankshaft 12 ... Auxiliary equipment 13 ... Belt 14 ... Starter motor 15 ... One-way clutch 16, 21 ... Inverter 17 ... Rotation speed sensor 20 ... Motor 22 ... Battery 30 ... Planetary gear 31 ... Sun gear 32a, 32b ... Pinion gear 33 ... planetary carrier 34 ... first clutch 35 ... rotating plate 36 ... ring gear 37 ... brake 38 ... second clutch 39 ... rotating plate 40 ... continuously variable transmission (CVT) 41, 42 ... pulley 43 ... belt 60 ... control unit

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) B60L 11/14 B60K 9/00 E (72) Inventor Takanori Moriya 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation F term (reference) 3D039 AA01 AA03 AA04 AB27 AC02 AC06 AC21 AC34 AD01 AD06 AD11 AD53 3D041 AA80 AB01 AC20 AD01 AE03 AE14 3G093 AA06 AA07 AA16 BA24 CA01 DB01 DB20 EA03 EB00 FA11 FB05 5H115 PG17 PU04 PI23 RB08 RB22 RB26 RE01 SE05 SJ12 TO21

Claims (10)

[Claims] An electric motor coupled to an engine via a coupling mechanism capable of coupling and detaching two rotating shafts, and a starter for engaging the coupling mechanism and powering the electric motor to rotate the engine. An engine starting device comprising: a control device; a detecting unit configured to detect a predetermined parameter corresponding to an actual rotation speed of the electric motor; and determining whether a rotation state of the electric motor is a predetermined target rotation state. An engine including: a determination unit that determines based on a detection result of a parameter; and an output unit that externally outputs a signal that prompts a predetermined operation for suppressing the actual rotation speed when it is determined that the target rotation state is deviated. Starting device. 2. The engine starting device according to claim 1, wherein the determination unit performs the determination based on whether the actual rotation speed exceeds an upper limit value of the rotation speed allowed for the electric motor. . 3. The engine starting device according to claim 2, wherein the electric motor is a permanent magnet type synchronous motor driven by a drive circuit, and the upper limit of the rotation speed is an induction motor generated by the electric motor. An engine starting device having a rotation speed set within a range in which a current flowing through the drive circuit by a voltage is equal to or less than an allowable value. 4. The determination means is a means for making the determination based on whether or not an actual rotation speed is a value greater than a rotation speed command value specified by the start control device by a predetermined value or more. The engine starting device according to claim 1. 5. The engine starting device according to claim 1, wherein the coupling mechanism is a one-way clutch capable of transmitting torque only from the electric motor to the engine. 6. The engine starting device according to claim 1, wherein the signal output by the output means is a signal for suppressing a rotation speed of the engine. 7. The engine starting device according to claim 1, wherein the signal output from the output means is a signal notifying that the rotation state of the electric motor is out of the target rotation state. 8. The engine starting device according to claim 1, wherein the electric motor is a permanent magnet type synchronous motor driven by a drive circuit, and further, when it is determined that the target rotation state is deviated. An engine starting device comprising: a current control unit that controls the inverter to supply a current that suppresses a magnetic field generated by the permanent magnet to the electric motor. 9. An engine control device for controlling the operation of an engine to which the engine start device according to claim 6 is coupled, wherein the number of revolutions of the engine is suppressed in accordance with a signal output from the engine start device. An engine control device including a rotation speed suppression control unit. 10. An electric motor coupled to the engine via a coupling mechanism capable of coupling and decoupling two rotating shafts,
A start control device for turning the engine by rotating the engine by powering the electric motor while bringing the coupling mechanism into an engaged state; Detecting the actual rotation speed of the electric motor; and (b) determining whether the coupling mechanism is stuck based on whether the rotation state of the electric motor specified by the actual rotation speed is a target rotation state. A fixation determination method for determining whether or not the fixation is performed.