JP2000104650A - Starting device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To start an internal combustion engine without using an excessively large electric motor. SOLUTION: This device adapts a brushless DC electric motor as a starter, which is equipped with a magnetic rotor 102 mounted to the crank shaft of an engine, and with a stator 103 wherein each armature coil W1 through W24 is wound around each tooth part P1 through P24 of an armature core 104 so as to allow the armature coils to be wired in there phase. A position where the center position of each magnetic pole of the magnetic rotor 102 coincides with the center position of the magnetic part of each tooth part of the stator 103, is made to be a reference excitation change-over position, and a control lead angle with respect to the reference excitation change-over position at a position where the excitation phase of armature coils W1 through W24 is changed over, is changed in response to the instant revolution when an internal combustion engine is started, so as to increase the revolution for generating the maximum torque of the electric motor as the instant revolution at the time of engine starting is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine starting apparatus for starting an internal combustion engine using an electric motor.

[0002]

2. Description of the Related Art As a starting device for starting an internal combustion engine, a device for starting an engine by rotating a crankshaft of the engine using a DC motor as a drive source is widely used.

FIG. 8A shows a main part of an internal combustion engine 1 provided with a conventional starting device. In FIG. 8A, reference numeral 2 denotes a case of the internal combustion engine 1; Is the output shaft (usually the crankshaft) of the engine supported via A flywheel 5 formed in a cup shape is attached to the tip of the output shaft 3, and a permanent magnet 6 is attached to the inner periphery of the peripheral wall of the flywheel 5 to form a magnet field. The flywheel 5 and the permanent magnet 6 constitute a magnet rotor 7. Inside the magnet rotor 7,
A stator 10 including a multipolar star-shaped armature core 8 having a structure in which a number of teeth protrude radially from an annular yoke and a power generation coil 9 wound around the teeth of the armature core is arranged. The stator is attached to a base plate 11 fixed to a case 2 of the engine. A magnet generator is constituted by the magnet rotor 7 and the stator 10.

A ring gear 12 is fixed to the outer periphery of the peripheral wall of the flywheel 5, and a DC motor 13 with a brush is mounted on the case 2 of the engine. A pinion gear 14 is attached to the output shaft 13a of the electric motor 13, and when the electric motor 13 is driven, the pinion gear 14 projects forward and meshes with the ring gear 12 as shown in FIG. 8B. . Electric motor 13 and pinion gear 1
4 and the ring gear 12 constitute an internal combustion engine starting device.

The generator coil provided on the stator 10 includes an ignition device driving coil for generating a voltage for driving an ignition device for an internal combustion engine. When the electric motor 13 is driven, the pinion gear 14 is turned on. The crankshaft of the engine is rotated by rotating the magnet rotor 7 while meshing with the ring gear 12, and ignition is performed by a voltage induced in an ignition device drive coil provided on the stator 10 with the rotation of the magnet rotor 7. The internal combustion engine is started by operating the device.

[0006]

As described above, in the conventional internal combustion engine starting apparatus, a DC motor with a brush is exclusively used as the starting motor 13. The output torque versus rotation speed characteristics of the starting device using a brushed DC motor as a driving source is, for example, as shown by a straight line a in FIG. The vertical axis in FIG. 5 shows the output torque (torque measured on the crankshaft) τ in terms of the crankshaft of the engine, and the horizontal axis shows the rotational speed N [rpm] of the crankshaft of the engine.

[0007] As described above, the output torque versus rotation speed characteristic of the starting device using a brushed DC motor as a driving source is as follows.
The characteristic is such that the torque is maximum at the time of startup, and the torque decreases as the rotation speed increases.

On the other hand, looking at the relationship between the torque (load torque) required to be applied to the crankshaft at the time of starting the internal combustion engine and the rotational speed of the crankshaft (cranking rotational speed), the cranking rotational speed is low. Sometimes, a characteristic is required in which the load torque is small, and the load torque increases as the cranking speed increases.

That is, in a two-cycle engine, when the cranking speed is low, the amount of air escaping from the cylinder through the intake port and the exhaust port during the compression stroke is large, so that the pressure in the combustion chamber does not increase so much. As the ranking rotation speed increases, the amount of air escaping from the cylinder decreases, and the pressure in the combustion chamber increases. In the case of a four-cycle internal combustion engine, when the cranking speed is low, the amount of air leaking at the beginning of the compression stroke due to the delay of the valve closing timing increases, so that the pressure increase in the combustion chamber at low speed is suppressed. However, as the cranking speed increases, the pressure in the combustion chamber increases because there is no delay in closing the valve.

FIG. 6 shows an example of a cranking characteristic when starting a three-cylinder two-stroke internal combustion engine. In FIG. 6, the vertical axis represents the load torque τ of the crankshaft and the instantaneous rotation speed N. ing. The horizontal axis is the rotation angle θ of the crankshaft.
TDC1, TDC2, and TDC3 indicate the rotational angle positions of the crankshaft when the pistons of the first to third cylinders reach the top dead center, respectively. In the figure, NL indicates the instantaneous rotation speed at each rotation angle position of the crankshaft when the average rotation speed of the crankshaft during cranking (rotating the crankshaft by external force) is low, and NH is the crankshaft. It shows the instantaneous rotation speed at each rotation angle position of the crankshaft when the average rotation speed of the crankshaft during ranking is high. Further, τL indicates the load torque at each rotation angle position of the crankshaft when the average rotation speed of the crankshaft during cranking is low, and τH
Indicates the load torque at each rotational angular position of the crankshaft when the average rotational speed of the crankshaft during cranking is high.

As described above, when the internal combustion engine is started, the pressure in the combustion chamber does not increase so much when the cranking speed is low, and the pressure in the combustion chamber increases as the cranking speed increases. Because of these characteristics, the relationship between the torque required to be applied to the crankshaft to rotate the crankshaft to overcome the pressure increase in the combustion chamber and the cranking speed is shown by a straight line b in FIG. become. The characteristics of the straight line b are opposite to the output characteristics of the brushed DC motor (the characteristics of the straight line a).

As the cranking speed increases, the pressure inside the combustion chamber increases, while the expansion force generated after the piston has passed the top dead center increases. The torque (the value of the torque .tau.H at the peak of the curve NH in FIG. 6) actually required at the peak speed N5 (the speed at the peak point of the curve NH in FIG. 6) at the start is shown in FIGS. .Tau.HN shown in FIG. If the starting device cannot generate a torque equal to or more than the required torque τHN at the peak rotational speed N5, the engine cannot follow the rotation of the crankshaft, and the engine decelerates, and the engine may fail to start.

For this reason, in the conventional starting apparatus, a starting motor having an output characteristic as shown by a straight line a in FIG. 5 is used so that the required torque τHN is obtained at the peak rotation speed N5 at the time of starting. However, when such a starting motor is used, a considerable margin is generated in the torque at a low speed.

As described above, in the conventional internal combustion engine starting device, it is necessary to use a brushed DC motor having a considerable margin for the maximum torque. Therefore, the motor becomes large and the starting device becomes large. Had the problem of becoming large.

SUMMARY OF THE INVENTION An object of the present invention is to provide an internal combustion engine starting device which uses a smaller motor than before and can obtain a cranking rotational speed required for starting the engine.

[0016]

The present invention relates to an internal combustion engine starting device for starting the internal combustion engine by driving a crankshaft of the internal combustion engine by an electric motor. In the present invention, the motor is a brushless DC motor. Use an electric motor. The brushless DC motor used in the present invention has a magnet rotor that has a multi-pole magnet field and is coupled to a crankshaft of an internal combustion engine directly or through a speed reducer, and has a number of teeth arranged in a circumferential direction. An armature core and an n-phase armature coil formed of a coil group wound around teeth of the armature core and connected to form an n-phase circuit (n is an integer of 2 or more). A switch circuit comprising a stator having a magnetic pole formed at the tip of a tooth of an armature iron core facing a magnetic field of a magnet rotor, and 2n on-off controllable switch elements connected in an n-phase bridge. An inverter circuit having
The positional relationship between the center position of the magnetic pole portion at the tip of the tooth portion of the armature core around which the armature coil of each phase is wound and the center position of each magnetic pole of the magnet field becomes a preset relationship. A position detecting device that detects the position as a reference excitation phase switching position of each phase, generates a rectangular wave signal whose level changes at the reference excitation phase switching position as a position detection signal of each phase, and starts the internal combustion engine. The drive current of the polarity required to rotate the magnet rotor in the direction from the DC power supply to the armature coil through the predetermined switch element of the inverter circuit to the reference excitation phase switching position detected by the position detection signal of each phase A switch control device for supplying a drive signal to a predetermined switch element of the inverter circuit at an excitation phase switching position having a predetermined control advance angle.

The switch control device includes a rotation speed detecting means for detecting an instantaneous rotation speed at the time of starting the internal combustion engine, and an electric motor which operates at a maximum as the instantaneous rotation speed of the internal combustion engine increases. Control advance angle control means for changing the control advance angle in accordance with the instantaneous rotational speed at the time of starting the internal combustion engine is provided so as to increase the rotational speed at which the torque is generated.

The "control advance angle" is defined as a reference excitation phase switching position detected by the position detection device and an actual excitation phase switching position (rotation angle of the rotor when switching the phase of the armature coil through which the drive current flows). In the present invention, it is assumed that the control advance angle can take a positive or negative value. That is, even when the actual excitation phase switching position is a position on the lag side with respect to the reference excitation phase switching position, the phase difference between the excitation phase switching position and the reference excitation phase switching position is referred to as “control advance angle”. I will. The “excitation phase switching position having a predetermined control advance angle with respect to the reference excitation phase switching position” includes a case where the excitation phase switching position matches the reference excitation phase switching position (when the control advance angle is zero). I do.

In a brushless DC motor of three or more phases, the armature coils of two or more phases are excited at a time, and the combination of excitation phases is sequentially switched according to the position of the rotor. Therefore, the excitation phase switching position of the brushless DC motor having three or more phases is a position at which the combination of the excitation phases of the armature coils is switched.

The reference excitation phase switching position is not uniquely determined by the mechanical structure of the brushless DC motor, but is determined by the mounting position of the position detector constituting the position detecting device. In a normal brushless DC motor, the position of the position detector is set to an appropriate position according to the conduction angle (electrical angle) of the drive current flowing through the armature coil of each phase. For example, the position at which the no-load induced voltage induced in the armature coil of each phase with the rotation of the magnet rotor reaches a peak (the magnetic flux flowing from the magnet field through the teeth around which the armature coil of each phase is wound) When the motor is rotated by performing 180-degree switching control in which current flows through the armature coil of each phase before and after 90 degrees (electrical angle) before and after the zero point), the armature coil of each phase is wound. Each phase is detected so that the rotation angle position of the rotor when the center position (circumferential center) of the magnetic pole portion at the tip of the tooth portion coincides with the center position of each magnetic pole of the magnet field of the rotor. The position detector for obtaining the position detection signal of the above is attached. For example, as shown in FIG. 2, U-phase to W-phase armature coils Lu to L
When w is wound around the three teeth Pu to Pw, the U-phase used for the 180-degree switching control is detected by detecting the magnetic poles of the magnet rotor using the position detectors hu to hw composed of Hall ICs. In order to obtain the position detection signals of W to W phases, the position detectors hu to hw are arranged at positions advanced by 90 degrees from the center positions of the magnetic poles of the teeth Pu to Pw, respectively, as shown in FIG. By detecting the magnetic poles of the magnets, the level changes each time the center position of each magnetic pole of the magnet field coincides with the center position of the magnetic pole part at the tip of the teeth Pu to Pw. Usually, a position detection signal is obtained. In this case, the teeth Pu to P
The position where the center position of each magnetic pole of the magnet field coincides with the center position of the magnetic pole portion at the tip of w is the U-phase or W-phase reference excitation phase switching position, and the reference excitation phase switching position of each phase is Are the positions where the level of the rectangular wave position detection signal obtained from the position detector changes (the rising position and the falling position of the rectangular wave signal).

A 120-degree switching control in which a current flows through the armature coil of each phase in a 60-degree interval before and after the position where the no-load induced voltage induced in the armature coil of each phase with the rotation of the magnet rotor reaches a peak. Is performed, the U-phase to W-phase position detectors hu to hw are arranged at positions advanced by 60 degrees from the center positions of the magnetic pole portions of the tooth portions Pu to Pw, respectively, and the magnet field is rotated. By detecting the magnetic poles of the magnets, the level changes each time the center position of each magnetic pole of the magnet field coincides with a position delayed by 30 degrees in electrical angle from the center position of the magnetic pole portion at the tip of the teeth Pu to Pw. It is usual to obtain a U-phase or W-phase position detection signal in the form of a square wave. In this case, the position when the center position of each magnetic pole of the magnet field coincides with a position delayed by 30 electrical degrees from the center position of the magnetic pole portion at the tip of the tooth portion Pu to Pw is the reference excitation phase. The switching position is set, and the reference excitation phase switching position of each phase is a position where the level of the position detection signal obtained from the position detector of each phase changes.

When the brushless DC motor is rotated by performing the 180-degree switching control or the 120-degree switching control, the position detector is arranged as described above to obtain the position detection signal of each phase. When the control advance angle is set to zero, that is, the combination of the phases of the armature coils excited at the reference excitation phase switching position (the rising position and the falling position of the position detection signal) at which the level of the position detection signal of each phase changes. By controlling the switch element of the inverter so as to switch to a predetermined combination, the output torque at the time of starting the motor can be maximized. However, the mounting position of the position sensor does not always have to be set as described above, and the reference excitation phase switching position is set to a position convenient for the control of the inverter circuit, and the reference excitation phase switching position is set at the reference excitation phase switching position. A position sensor may be attached so as to generate a detection signal.

As described above, the control proceeds according to the instantaneous rotation speed at the start of the internal combustion engine so that the rotation speed at which the electric motor generates the maximum torque increases with the increase in the instantaneous rotation speed of the internal combustion engine. If the angle is changed, the output torque of the motor and the torque required to rotate the crankshaft of the engine at each moment from the start of the engine start to the point when the engine speed reaches the peak speed at the start of the engine Therefore, the crankshaft can be rotated without making the difference excessively large, so that the internal combustion engine can be started without using a large-sized motor that generates an excessive output torque at the start of starting. Therefore, it is possible to make the internal combustion engine starting device smaller than ever, and to reduce the size and weight of the engine.

In the present invention, when the magnet rotor is directly mounted on the crankshaft of the engine, a speed reducer for transmitting the output of the electric motor to the crankshaft is not required, so that the configuration of the starting device can be simplified. It is possible to simplify the structure of the engine.

The electric motor used in the present invention may be constituted by a rotor outside rotation type in which the rotor rotates outside the stator, or by a rotor inside rotation type in which the rotor rotates inside the stator. You may.

When the electric motor is of a rotor abduction type, the magnet rotor is substantially a cup which is coupled to the crankshaft of the internal combustion engine directly or via a reduction gear so as to rotate with the crankshaft of the internal combustion engine. And a magnet field formed on the inner periphery of the peripheral wall of the flywheel.

Further, in this case, the stator of the electric motor includes a multipole star-shaped armature core having a structure in which a large number of teeth protrude radially from an annular yoke, and a winding wound around the teeth of the armature core. An n-phase armature coil consisting of a coil group connected in a star shape so as to be turned to form an n-phase circuit (n is an integer of 2 or more). This stator is arranged inside the magnet rotor, and the magnetic pole at the tip of each tooth of the armature iron core faces the magnetic pole of the magnet field.

Further, 2n switches connected in anti-parallel to the 2n switch elements of the inverter circuit are provided, and the 2n diodes rectify the n-phase AC voltage induced in the n-phase armature coil. When a diode bridge full-wave rectifier circuit that supplies power to an external electric load is configured, the starting motor can have the function of a magnet generator, so the starting motor is also used as the magnet generator. In this way, the structure of the engine can be simplified.

[0029]

1A and 1B show an example of the configuration of a starting motor used in an internal combustion engine starting apparatus according to the present invention. In the present invention, this motor is a brushless DC motor. And start the engine.
In the present invention, a brushless DC motor having an n-phase (n is an integer of 2 or more) armature coil can be used as a starting motor. In this example, a three-phase brushless DC motor is used.

1A and 1B, reference numeral 101 denotes a peripheral wall portion 101a, a bottom wall portion 101b for closing one end of the peripheral wall portion in the axial direction, and a boss portion 101 provided at the center of the bottom wall portion.
c) is a cup-shaped flywheel having the following shape. On the inner circumference of the peripheral wall portion 101a of the flywheel 101, 16 arc-shaped permanent magnets M1 to M16 arranged at equal angular intervals are fixed by bonding or the like, and 16 permanent magnets M1 to M16 are fixed by the flywheel 101 and the permanent magnets M1 to M16. A pole magnet rotor 102 is configured. The magnets M1 to M16 are magnetized in the radial direction of the flywheel by alternately changing the magnetization directions so that the magnetic poles appearing on the inner peripheral side alternately become N poles and S poles, and are arranged in the flywheel. Peripheral wall 1 of wheel 101
The magnet field 01a and the magnets M1 to M16 form a 16-pole magnet field. The magnet rotor 102 is a flywheel 1
The boss 101c is mounted on an output shaft (usually a crankshaft) of an internal combustion engine (not shown) by fitting the boss 101c to the engine.

The stator 103 is provided inside the magnet rotor 102.
Is arranged. The stator 103 includes the annular yoke 10
4a to 24 tooth portions P1 to P24 for winding armature coils
A multi-pole star-shaped armature core 104 having a structure in which are projected radially at equal angular intervals (at intervals of 360/24 degrees);
Armature coils W1 to W24 wound around tooth portions P1 to P24 of the armature core, respectively.
04 is fixed to a stator mounting portion provided in a case or the like of an internal combustion engine by an appropriate means, thereby being mounted on the engine.

The armature coils W1 to W24 wound around the tooth portions P1 to P24 are coils that also serve as a starting motor and a generator, and are arranged in eight in-phase (in-phase) Armature coils (inducing voltage) are connected in series or in parallel to form armature coils of each phase, and three-phase armature coils are connected in a three-phase star connection.

Generally, in a three-phase brushless DC motor, the stator side has 3 m poles (m is an integer of 1 or more), and the magnet field of the magnet rotor is 2 m poles. In the illustrated example, when m = 8, the stator 103 has 24 poles, and the rotor 102 has 16 poles.

This type of brushless DC motor operates as a generator when the magnet rotor is rotated by an external force. At each rotation angle position of the magnet rotor, a magnetic pole of the same polarity of the magnet field is applied to the stator. The same phase voltage is induced in the armature coil of each phase wound around every third tooth part in the same manner as opposed to the magnetic pole part of the tooth part arranged at every third tooth. When operating as a motor, a driving current is supplied to the three-phase armature coils of the stator from a DC power supply through an inverter circuit described later in a predetermined phase order according to the rotational angle position of the magnet field. Then, the magnet rotor is rotated by the rotating magnetic field generated thereby.

In the example shown in FIG.
Permanent magnets M1 to M1 are provided on the outer periphery of the base of the first boss 101c.
A ring-shaped magnet 106 magnetized to 16 poles is attached so as to have magnetic poles respectively corresponding to the 16 magnetic poles, and the 16 magnetic poles of the ring-shaped magnet 106 each have one magnetic field.
The six magnetic poles correspond one to one at the same circumferential position. On the inner circumference of the yoke of the armature core 104, 3
Position detector hu corresponding to each of the armature coils of the phase
1 to hw (only the U-phase position detector hu is shown in FIG. 1) is attached at an angular interval of 120 degrees. The position detector of each phase is formed of a Hall IC, and outputs voltage signals of different levels according to the polarity of the magnetic pole being detected.

In this example, when a driving current is supplied from a DC power supply to a three-phase armature coil through a switching element of an inverter circuit to be described later to rotate a magnet rotor when the internal combustion engine is started, the armature of each phase is rotated. The 180-degree switching control is performed so that the drive current flowing through the coil has an electrical angle of 180 degrees in electrical angle. Therefore, in the illustrated example, 1
In accordance with the usual arrangement of the position detector when performing the 80-degree switching control, the position detector of each phase is replaced with a plurality of teeth of the armature core around which the armature coil of the corresponding phase is wound. It is disposed at a position where the phase is advanced by 90 degrees in electrical angle from the center position of the magnetic pole at the tip of any one of the teeth.
Then, by detecting the polarity of the magnetic pole of the ring-shaped magnet 106 by the position detector of each phase, the center of each magnetic pole of the magnet field is located at the center position of the magnetic pole portion of the tooth around which the armature coil of each phase is wound. The position at which the positions coincide with each other is detected as the reference excitation phase switching position of each phase.

The position detection signals generated by the position detectors hu to hw may be signals having a waveform including information on the reference excitation phase switching position. If a Hall IC is used as the position detector, the Hall IC is Since a signal of a different level is generated when the polarity of the detected magnetic pole is the N pole and when the polarity of the magnetic pole is the S pole, the waveform of the position detection signal becomes a rectangular waveform, The rising position and the falling position are the reference excitation phase switching positions.

FIG. 2 shows the tooth portions P 1 -P of the armature core 104.
24 shows a configuration of an electric circuit connected to armature coils wound around each and connected in three phases. FIG.
In order to facilitate understanding, a three-phase armature coil formed by connecting three-phase armature coils W1 to W24 with a three-phase star connection is denoted by Lu to Lw. It is assumed that the armature coils Lu to Lw of the phase are concentratedly wound around three teeth Pu to Pw of the armature core 104 arranged at intervals of 120 degrees. Further, it is assumed that the magnet field of the magnet rotor 102 is constituted by two poles by the permanent magnets M1 and M2.

In FIG. 2, the position detectors hu to h
It is shown that the Hall ICs constituting w each directly detect the magnetic poles of the magnet field, instead of the ring magnet provided for detecting the position of the magnet field of the rotor. The position detectors hu to hw are respectively disposed at positions advanced by 90 electrical degrees with respect to the center positions of the magnetic poles of the teeth Pu to Pw around which the U-phase to W-phase armature coils are wound. The polarity of the magnetic pole is detected. That is, in this example, the conduction angle of the drive current flowing through the armature coil of each phase is 180 electrical degrees.
Degree.

In FIG. 2, reference numeral 200 denotes an inverter circuit used to drive a three-phase brushless DC motor.
A switch circuit composed of a plurality of switch elements (MOSFETs in the illustrated example) capable of on / off control, Fu to Fw and Fx to Fz, and a three-phase bridge connected in antiparallel to the switch elements Fu to Fw and Fx to Fz, respectively. A diode bridge full-wave rectifier circuit is composed of six connected diodes Du to Dw and Dx to Dz and rectifies the voltage induced in the armature coils Lu to Lw.

In the inverter circuit 200, the switch elements Fu to Fw on the upper side of the bridge of the switch circuit are provided.
(The diodes Du to Dw forming the upper side of the bridge of the rectifier circuit)
Of the switching elements Fx to Fz on the lower side of the bridge of the switch circuit.
Terminals ta and tb respectively derived from the common connection point of the source of T (the common connection point of the anodes of the diodes Dx to Dz forming the lower side of the bridge of the rectifier circuit) are the DC input terminal of the switch circuit and the DC output terminal of the rectifier circuit. And a DC power supply 300 between these terminals ta and tb.
Is connected. Further, the sources of the MOSFETs constituting the switching elements Fu to Fw and the MOSs constituting the switching elements Fx to Fz, respectively.
A terminal tu drawn from a connection point with the drain of the FET.
To tw are an AC output terminal of the switch circuit and an AC input terminal of the rectifier circuit, and these terminals tu to tw are connected to terminals opposite to the neutral points of the armature coils Lu to Lw, respectively.

A smoothing capacitor C1 is connected to both ends of the battery B constituting the DC power supply 300.

Reference numeral 400 denotes a switch control device constituted by using a microcomputer, a logic circuit or the like. This switch control device has input terminals to which position detection signals Hu to Hw output from the position detectors hu to hw are input. And an output terminal for outputting drive signals Su to Sw and Sx to Sz to be applied to respective control terminals (gates of MOSFETs in the illustrated example) of the switch elements Fu to Fw and Fx to Fz. At the time of starting, a drive current having a polarity necessary for rotating the magnet rotor 101 in a direction for starting the internal combustion engine is supplied from the DC power supply 300 to the inverter circuit 200
At the excitation phase switching position determined based on the reference excitation phase switching positions detected for the three-phase armature coils by the position detectors hu to hw so as to flow to the armature coils Lu to Lw through the switch circuit section. The predetermined MOSF of the switch circuit
A drive signal is given to an ET (switch element).

As shown in FIG. 2, the three-phase position detectors hu to hw
Are 9 electrical degrees with respect to the center position of the magnetic poles of the teeth Pu to Pw around which the U-phase or W-phase armature coils are wound.
If the position detector is mounted at a position advanced by 0 degrees and outputs a high-level signal when the position detector detects the N pole, the position detection signals Hu to Hw generated by the position detectors hu to hw, respectively. The waveforms of (A) to (C) in FIG.
As shown in the figure, the signal width sequentially generated with a phase difference of 120 degrees in electrical angle becomes a 180-degree rectangular waveform. The rising position and falling position of the position detection signals Hu to Hw are the U-phase to W-phase reference excitation phase switching positions, respectively.

In the illustrated example, since the rotor has two poles, the magnetic flux linked to the armature coil and the electrical angle of the induced voltage of the armature coil (the phase angle of the magnetic flux waveform and the induced voltage waveform) are: It matches the mechanical angle (the phase angle expressed by the rotation angle of the rotor).

In the illustrated example, the position detectors hu to hw
Are located at positions where the phase is advanced by 90 degrees with respect to the center of the U-phase or W-phase magnetic poles of the stator, respectively, so that the position detection signals Hu to Hw are in the low level and in the high level. The period during which the magnet rotor is driven by the engine and operates as a generator is the period of one half cycle of the induced voltage induced in the U-phase to W-phase armature coils Lu to Lw and the other half cycle. Period. For example, the period in which the position detection signal Hu is at the low level corresponds to the period of the positive half cycle of the induced voltage of the U-phase armature coil Lu, and the period in which Hu is at the high level is the U-phase armature. This corresponds to the period of the negative half cycle of the induced voltage of the coil Lu.

In this example, on / off control of each switch element (180-degree switching) is performed such that each switch element constituting the switch circuit is turned on for an electrical angle of 180 degrees and turned off for the remaining 180 degrees. Control). In this case, for example, as shown in FIGS. 3D to 3I, reference switching patterns of the switch elements Fu to Fw and Fx to Fz are determined.

FIGS. 3D to 3I show the switching element F
The reference switch patterns u to Fw and Fx to Fz are shown by the waveforms of the drive signals Su to Sw and Sx to Sz applied to the respective switch elements, and are shown in FIGS. 3D to 3I, respectively. The high-level rectangular wave signals are the drive signals Su to Sw and Sx to Sz. A period during which these drive signals Su to Sw and Sx to Sz are generated is a drive period of the switch elements Fu to Fw and Fx to Fz,
A period during which the drive signals Su to Sw and Sx to Sz are not generated is a non-drive period of the switch elements Fu to Fw and Fx to Fz.

In the reference switch pattern of the 180-degree switching control shown in FIG. 3, the position detectors hu to hu for detecting the rotational angle positions of the magnet rotors for the U-phase to W-phase armature coils Lu to Lw, respectively. The period in which each of the position detection signals Hu to Hw obtained from hw is at a high level (the period in which each position detector detects one magnetic pole of the magnet field) corresponds to the corresponding switch element Fu on the upper side of the bridge. To Fw, and the period in which the position detection signals Hu to Hw are at a low level is a drive period of the corresponding switch element Fu to Fw on the upper side of the bridge. The non-driving periods of the switch elements Fu to Fw on the upper side of the bridge of the switch circuit (periods during which the position detectors hu to hw are detecting the other magnetic poles of the magnet field) respectively correspond to the corresponding switches on the lower side of the bridge. The drive periods of the elements Fx to Fz are set as switch elements Fu to F on the upper side of the bridge.
The drive period of w is a non-drive period of the corresponding switch element Fx to Fz on the lower side of the bridge.

The switch elements Fu to Fw and Fx in the reference switch pattern as shown in FIGS.
To Fz are turned on and off, an AC voltage having the same phase as the voltage (induced voltage as a generator) induced in the armature coils Lu to Lw when the magnet rotor is rotated is transmitted from the battery B to the switch elements Fu to Fw. And armature coils Lu to Lw through a switch circuit composed of
, And the magnet rotor 102 is rotated by a rotating magnetic field generated by a current flowing through the armature coil.

In the starting device of the present invention, when the internal combustion engine is started, the switch control device 400 sets the excitation phase switching position (γ = 0, γ = 0) having a predetermined control advance angle γ with respect to a predetermined reference excitation phase switching position. The drive signals Su-Sw and Sx-Sz are supplied to the switch elements Fu-Fw and Fx-Fz of the inverter circuit 200, respectively, including the case where the excitation phase switching position coincides with the reference excitation phase switching position. A driving current that is commutated in a predetermined phase sequence is supplied to the child coils Lu to Lw, thereby rotating the magnet rotor 102 and rotating the output shaft of the engine in the starting direction.

In the electric motor shown in FIG.
When a drive current flows from the side to the armature coils Lu to Lw,
When the phases of the actual switch patterns of the switch elements Fu to Fw and Fx to Fz are changed with reference to the reference switch pattern shown in FIG. 3, the armature coils Lu to Lw
The output characteristic as a generator can be changed by increasing or decreasing the amount of magnetic flux interlinking with. The phase difference γ between the actual switch pattern phase of the switch elements Fu to Fw and Fx to Fz and the reference switch pattern is called a control advance angle. By changing the control lead angle γ,
Various characteristics of the motor can be changed.

FIG. 4 shows an example of the relationship between the output torque τ of the motor and the drive current I and the relationship between the rotational speed N and the drive current I when the control lead angle γ is changed. In the figure, τγ0, τγ1 and τγ2 indicate output torques when the control advance angle γ is 0, γ1 and γ2 (> γ1), respectively, and Nγ0, Nγ1 and Nγ2 indicate the control advance angles γ of 0, γ1 and γ2 ( > Γ1).

FIG. 5 shows a case where the position where the center position of each magnetic pole of the magnet field coincides with the center position of the magnetic pole portion of the tooth around which the armature coil of each phase is wound is set as the reference excitation phase switching position. Output torque τ when the control lead angle γ is changed
And the relationship between the rotation speed N and the rotation speed N.

As is apparent from FIG. 5, when the control advance angle γ is set to 0, the output torque τ at the time of startup (when N = 0) is set.
Is maximized, and the control lead angle γ is changed to γ1 (> 0), γ2 (>
When the output torque is increased as in γ1), the position where the output torque becomes maximum moves to the high rotation side, and the output torque at each rotation speed increases. Therefore,
When the instantaneous rotational speed of the engine at each rotational angle position of the crankshaft of the engine is detected at the start of the engine, and the control advance angle γ is changed from 0 → γ1 → γ2 according to the detected instantaneous rotational speed, the engine is started. At the rotation speeds N1, N2 and N3 at the time, the torque required to rotate the crankshaft by overcoming the pressure in the combustion chamber can be obtained, and then the conventional starting using a brushed DC motor as the starting motor. By increasing the rotational speed while decreasing the output torque along the straight line a indicating the cranking characteristics of the device, the required torque .tau.HN can be finally obtained at the peak rotational speed N5 at the start. FIG. 7 shows control characteristics of the control lead angle γ with respect to the rotation speed N in this case.

As described above, the control proceeds in accordance with the instantaneous rotation speed at the start of the internal combustion engine so that the rotation speed at which the electric motor generates the maximum torque increases as the instantaneous rotation speed of the internal combustion engine increases. If the angle is changed, the output torque of the motor and the torque required to rotate the crankshaft of the engine at each moment from the start of the engine start to the point when the engine speed reaches the peak speed at the start of the engine Therefore, the crankshaft can be rotated without making the difference excessively large, so that the internal combustion engine can be started without using a large-sized motor that generates an excessive output torque at the start of starting. Therefore, it is possible to make the internal combustion engine starting device smaller than ever, and to reduce the size and weight of the engine.

In order to control the control advance angle as described above,
In the present invention, the switch control device 400 includes a rotation speed detection unit that detects an instantaneous rotation speed when the internal combustion engine is started,
Control is performed according to the instantaneous rotation speed at the time of starting the internal combustion engine so that the rotation speed at which the electric motor generates the maximum torque increases with the increase in the instantaneous rotation speed of the internal combustion engine detected by the rotation speed detection means. And a control lead angle control means for changing the lead angle.

The above-mentioned rotation speed detecting means and control lead angle control means can be realized by using, for example, a microcomputer. When a microcomputer is used, the rotation speed detecting means may be, for example, a three-phase position detector hu, hv
A position detection signal generation interval measuring means for measuring the generation intervals of the position detection signals Hu, Hv, and Hw sequentially output from the output signal and hw; Can be configured.

The control advance angle control means is, for example, a control advance angle γ with respect to the calculated instantaneous rotation speed at the time of starting the engine.
And a control lead angle calculating means for calculating an appropriate value of the control lead angle by map calculation, and a control lead angle calculated by the control lead angle γ calculated when the reference excitation phase switching position of each phase is detected from the position detection signals Hu to Hw. A drive signal supply unit that measures a measurement time by a timer and supplies a drive signal to a predetermined switch element of the inverter circuit 200 when the measurement of the control lead angle measurement time is completed.

When the control advance angle is obtained by map calculation, the relationship between the rotational speeds of various values taking discrete values in the change range of the rotational speed at the start and the control advance angle γ at each rotational speed is determined. The given table is stored in the ROM of the microcomputer as a control lead angle calculation map. Then, among the discrete values of the rotational speed constituting the map, the control advance angle values for the values before and after the instantaneous rotational speed calculated by the rotational speed calculation means are read from the map, and the read control advance angle is used. An appropriate control lead angle γ for the instantaneous rotation speed calculated by performing the interpolation calculation is calculated. In this case, the value of the control advance angle that forms the control advance angle calculation map may be determined by experiment.

After the internal combustion engine is started, the drive signals Su to
The output of Sw and Sx to Sz is stopped, and the armature coil L
u to Lw are used as power generation coils, and three-phase voltages V induced in the armature coils Lu to Lw as the magnet rotor rotates.
u, Vv, and Vw are rectified by a full-wave rectifier circuit composed of diodes Du to Dw and Dx to Dz of the inverter circuit 200 and applied to the battery B as a charging voltage.

As described above, when the battery is charged by operating the electric motor as a generator after the engine is started, it is not necessary to separately provide a generator for charging the battery, thereby simplifying the configuration of the engine. it can. The voltage of the battery B is used for driving electrical components such as an internal combustion engine ignition device and a fuel injection device.

In the above example, the control advance angle is controlled only for the instantaneous rotation speed. However, the control advance angle may be controlled by associating the instantaneous rotation speed with the average rotation speed.
For example, the instantaneous engine speed can be expressed as “instant engine speed = average engine speed ± change in engine speed”, so the average engine speed is detected and the engine speed is calculated based on the detected average engine speed and instantaneous engine speed. By calculating a change in the number and controlling the control advance angle with respect to the change in the rotational speed, the control advance angle may be indirectly controlled with respect to the instantaneous rotational speed.

In the above example, the position detectors hu to hw indirectly detect the rotation angle position of the magnetic field of the magnet rotor relative to the teeth of the armature iron core by detecting the magnetic poles of the ring magnet. Although the position detection signal is generated by using the position detection signal as shown in FIG. 2, the position detection signal may be obtained by directly detecting the magnetic pole of the magnet field by the position detector.

The position detector only needs to detect that the center position of each magnetic pole of the magnet field has reached a position having a predetermined relationship with the center position of the teeth of the armature core. It is not necessary to detect the magnetic pole of the magnet field. For example, by attaching the rotor of the rotary encoder to the magnet rotor, attaching the stator of the rotary encoder to the stator side, and counting pulse signals generated each time the magnet rotor rotates by a small angle with the rotary encoder. Alternatively, it may be detected that the center position of each magnetic pole of the magnet field has reached a position having a predetermined relationship with the center position of the teeth of the armature core.

In the above example, the magnet rotor is directly mounted on the crankshaft of the engine. However, the magnet rotor may be mounted on a shaft connected to the crankshaft via a speed reducer.

It is preferable to operate the motor as a generator after the engine is started, as in the above example. However, like the conventional internal combustion engine starting device, the starting motor is dedicated to starting the engine. It may be used.

[0068]

As described above, according to the present invention, the starting speed of the internal combustion engine is increased so that the rotating speed at which the electric motor generates the maximum torque increases with the instantaneous rotating speed of the internal combustion engine. Since the control advance angle is changed in accordance with the instantaneous rotation speed, the output torque of the electric motor and the crankshaft of the engine at each moment from the start of the engine start to the point when the engine speed reaches the peak rotation speed at the start of the engine. Since the crankshaft can be rotated without increasing the difference from the torque required for rotating the shaft, the internal combustion engine can be used without using a large motor that generates excessive output torque at the start of starting. Can be started. Accordingly, there is an advantage that the internal combustion engine starting device can be made smaller than before and the engine can be made smaller and lighter.

[Brief description of the drawings]

1A and 1B show a configuration example of a starting motor according to the present invention, wherein FIG. 1A is a front view, and FIG. 1B is a cross-sectional view taken along line Y-Y of FIG.

FIG. 2 is a circuit diagram showing a configuration example of a circuit connected to an armature coil of the electric motor shown in FIG.

FIG. 3 is a waveform diagram showing signal waveforms of various parts of the electric motor of FIG.

FIG. 4 is a diagram showing a change in characteristics of the electric motor of FIG. 1 with respect to a drive current of an output torque and a rotation speed when a control advance angle is changed.

FIG. 5 is a diagram showing a change in output torque versus rotation speed characteristics when the control lead angle is changed in the electric motor of FIG. 1 together with characteristics showing a relationship between torque and rotation speed required at the time of starting of the engine; It is.

FIG. 6 is a graph showing the relationship between the cranking rotational speed N and the required torque τ when cranking is performed at the time of starting the engine and the rotational angle θ of the crankshaft; FIG. 4 is a diagram illustrating a case where the value is low and a case where the value is high.

FIG. 7 is a diagram showing an example of a control characteristic of a control advance angle in a starting device according to the present invention.

FIG. 8A is a sectional view showing a main part of a conventional starting device. (B) is a left side view of the main part of (A).

[Explanation of symbols]

101: flywheel, 102: magnet rotor, 103
... stator, 104 ... armature iron core, P1 to P24 ... tooth, W
1 to W24: armature coil, M1 to M16: permanent magnet, 20
0: Inverter circuit, 300: DC power supply, 400: Switch control device.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Mitsuyoshi Shimazaki 3744 Ooka, Numazu-shi, Shizuoka Japan F-term (reference) 5H019 BB01 BB05 CC04 CC09 DD01 EE01 EE14 FF01 5H621 BB10 GA01 GA04 HH01 JK14 JK15

Claims (5)

[Claims] 1. An internal combustion engine starting device for starting the internal combustion engine by driving a crankshaft of the internal combustion engine by an electric motor, wherein the electric motor has a multi-pole magnet field and is directly connected to the crankshaft of the internal combustion engine. Alternatively, a magnet rotor coupled via a speed reducer, an armature core having a large number of teeth arranged in the circumferential direction, and an n-phase circuit wound around the teeth of the armature core (n is an integer of 2 or more) And an n-phase armature coil consisting of a coil group connected to form a magnetic pole portion formed at the tip of the tooth portion of the armature iron core facing the magnet field of the magnet rotor. Stator and n-phase bridge-connected 2
an inverter circuit including a switch circuit including n switch elements capable of on / off control; a center position of a magnetic pole portion at a tip end of a tooth portion of an armature core around which the armature coil of each phase is wound; A position where the positional relationship between the center position of each magnetic pole of the magnet field and the center position is set in advance is detected as a reference excitation phase switching position of each phase, and a rectangle whose level changes at the reference excitation phase switching position is detected. A position detection device for generating a wave-like signal as a position detection signal for each phase; and a drive current having a polarity necessary for rotating the magnet rotor in a direction for starting the internal combustion engine is supplied from a DC power supply to a predetermined position of the inverter circuit. At the excitation phase switching position having a predetermined control advance angle with respect to the reference excitation phase switching position detected by the position detection signal of each phase so as to flow to the armature coil through the switch element. A brushless DC motor including a switch control device for providing a drive signal to a predetermined switch element of the circuit, wherein the switch control device includes a rotation speed detection unit that detects an instantaneous rotation speed at the time of starting the internal combustion engine; According to the instantaneous rotation speed at the time of starting the internal combustion engine, the rotation speed at which the electric motor generates the maximum torque increases with the increase in the instantaneous rotation speed of the internal combustion engine detected by the rotation speed detection means. And a control lead angle control means for changing the control lead angle. 2. An internal combustion engine starting device for starting the internal combustion engine by driving a crankshaft of the internal combustion engine by an electric motor, wherein the electric motor includes a flywheel formed substantially in a cup shape and a peripheral wall portion of the flywheel. A magnet rotor having a magnet field formed on the periphery thereof, the magnet rotor being coupled to the crankshaft of the internal combustion engine directly or via a reduction gear so that the flywheel rotates with the crankshaft of the internal combustion engine. A multipolar star-shaped armature core having a structure in which a number of teeth protrude radially from an annular yoke, and an n-phase circuit (n is an integer of 2 or more) wound around the teeth of the armature core And an n-phase armature coil composed of a star-connected coil group and a stator arranged inside the magnet rotor, and 2n on-off controls connected by an n-phase bridge Switch capable A DC voltage is applied between the DC input terminals, and an inverter circuit in which the n-phase armature coil is connected to the n-phase AC output terminal, and the armature coil of each phase is wound. The position at which the positional relationship between the center position of the magnetic pole portion at the tip of the tooth portion of the armature iron core and the center position of each magnetic pole of the magnet field becomes a preset relationship is a reference excitation phase switching position of each phase. And a position detection device that generates a rectangular wave signal whose level changes at the reference excitation phase switching position as a position detection signal for each phase, and rotates the magnet rotor in a direction to start the internal combustion engine. In order to allow the drive current of the required polarity to flow from the DC power supply to the armature coil through the inverter circuit, a predetermined excitation phase switching position detected for the armature coil of each phase by the position detection device is determined. System A switch control device for providing a drive signal to a predetermined switch element of the inverter circuit at an exciting phase switching position having a lead angle, the brush control device comprising: A rotation speed detecting means for detecting a rotation speed, and increasing the rotation speed at which the electric motor generates the maximum torque with an increase in the instantaneous rotation speed of the internal combustion engine detected by the rotation speed detecting means, An internal combustion engine starting device, comprising: a control advance angle control unit that changes the control advance angle according to the instantaneous rotation speed at the time of starting the internal combustion engine. 3. An internal combustion engine starting device for starting the internal combustion engine by driving a crankshaft of the internal combustion engine by an electric motor, wherein the electric motor includes a flywheel formed substantially in a cup shape and a peripheral wall portion of the flywheel. A magnet rotor having a magnet field formed on the periphery and coupled to the crankshaft of the internal combustion engine directly or via a speed reducer so that the flywheel rotates with the crankshaft of the internal combustion engine; A multipole star-shaped armature core having a structure in which a number of teeth protrude radially from an annular yoke portion and an n-phase circuit (n is an integer of 2 or more) wound around the teeth of the armature core. A stator arranged inside the magnet rotor having an n-phase armature coil composed of a group of coils connected in a star shape so as to constitute, and 2n on-off controls connected by an n-phase bridge are provided. Possible switch elements , And 2n diodes connected in anti-parallel to the 2n switch elements, respectively. A DC voltage is applied between DC input terminals of the switch circuit, and the n-phase AC output terminal is connected to the n-phase AC output terminal. An n-phase inverter circuit to which a phase armature coil is connected, a center position of a magnetic pole portion at a tip of a tooth portion of an armature core around which the armature coil of each phase is wound, and each magnetic pole of the magnet field Is detected as a reference excitation phase switching position for each phase, and a rectangular wave signal whose level changes at the reference excitation phase switching position is detected for each phase. And a drive current having a polarity required to rotate the magnet rotor in a direction to start the internal combustion engine from a DC power supply through the inverter circuit. In the excitation phase switching position having a predetermined advance control angle with respect to the reference excitation phase switching position detected for the armature coil of each phase by the position detection device so as to flow to the predetermined switch element of the inverter circuit. A switch control device for providing a drive signal, the switch control device comprises: The control advance angle is changed in accordance with the instantaneous rotation speed at the time of starting the internal combustion engine so that the rotation speed at which the electric motor generates the maximum torque increases with the increase in the instantaneous rotation speed of the internal combustion engine. And a lead angle control unit for rectifying an n-phase AC voltage induced in the n-phase armature coil by 2n diodes of the inverter circuit, Internal combustion engine starting apparatus characterized by supplying the gas-load diode bridge full-wave rectifier circuit is constituted. 4. The position detecting device according to claim 1, wherein the position of the center of the magnetic pole at the tip of the tooth around which the armature coil of each phase is wound coincides with the center of the magnetic pole of the magnet field. The control advance angle control unit is configured to generate a position detection signal, which detects the excitation phase switching position and changes the level at the reference excitation phase switching position, for each phase. The control advance angle is set to zero, and the control advance angle is controlled so that the control advance angle increases toward the advance side as the instantaneous rotational speed of the internal combustion engine increases. The internal combustion engine starting device according to any one of the above. 5. The apparatus according to claim 1, wherein the rotation speed detection means calculates the instantaneous rotation speed from an interval of generation of n-phase position detection signals sequentially generated by the position detection device. An internal combustion engine starting device according to one of the preceding claims.