JP2003074446A - Engine starting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact and inexpensive engine starting system capable of reducing the load in starting the engine. SOLUTION: A starter motor 6 for starting the engine is connected to one end side of a crank shaft 5. A centrifugal clutch 3 is mounted at the other end side of the crank shaft 5 positioned at a side opposite to the stator motor 6 through the engine 1. The centrifugal clutch 3 comprises a driving part 10, and a driven part 11 connected when the driving part 10 has more than a predetermined rotating speed. The driven part 11 is connected to a driving pulley 7 of a belt-type continuously variable transmission 2. The driving pulley 7 is connected to a driven pulley 9 through a V-belt 8. The driven pulley 9 is connected to a driving shaft 12 for driving rear wheels 4. The centrifugal clutch 3 is kept in an OFF condition when the engine is started, so that the load after the driven part 11 such as the friction by the V-belt 8 does not act on the starter motor 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine starting system, and more particularly to a technique effectively applied to a motorcycle equipped with a belt type continuously variable transmission.

[0002]

2. Description of the Related Art In motorcycles such as scooters (hereinafter abbreviated as "two-wheeled vehicles"), since a vehicle speed control is easy and driving is easy, a vehicle equipped with a V-belt type continuously variable transmission is widely used. It is used. FIG. 2 is an explanatory diagram showing the configuration of a power transmission system in a two-wheeled vehicle equipped with such a belt type continuously variable transmission. As shown in FIG. 2, in the motorcycle, the power of the engine 51 is transmitted to the rear wheels 54 via a belt type continuously variable transmission 52 (hereinafter abbreviated as the transmission 52) and a centrifugal clutch 53.

A starter motor 56 for starting the engine is attached to one end of the crankshaft 55 of the engine 51. Further, on the other end side of the crankshaft 55, that is, on the opposite side of the starter motor 56 across the engine 51, the drive pulley 57 of the transmission 52 is provided.
Is attached. The drive pulley 57 is connected to a driven pulley 59 by a V belt 58.

A centrifugal clutch 53 is arranged on the driven pulley 59 side. In this case, the driven pulley 59 is connected to the drive unit 60 of the centrifugal clutch 53. On the other hand, the driven portion 61 of the centrifugal clutch 53 is connected to a drive shaft 62 for driving the rear wheel 54. The drive shaft 62 is connected to the rear wheel 54 via a gear train 63.

When the engine 51 having such a power transmission system is started, the starter motor 56 is driven by a battery (not shown) as a power source to rotate the crankshaft 55. As a result, the engine 51 is started, the throttle valve is opened by the accelerator operation, and the rotational speed of the engine 51 increases.
3 is connected and the rear wheel 54 is driven.

[0006]

However, when the engine 51 is started by such a power transmission system, the starter motor 56 includes the piston compression load of the engine 51 and the friction of each part of the engine, as well as the transmission 52 and thereafter. Load. That is, it is necessary to crank the engine 51 at a rotational speed that is higher than or equal to the startable speed in a state where a load is applied by the drive pulley 57, the driven pulley 59, the drive unit 60 of the centrifugal clutch 53, and the like.

Further, in the belt type continuously variable transmission, the friction caused by driving the belt is large, and the friction is further increased because the belt is stiff especially at low temperatures. In addition, when the temperature is low, the viscosity of the engine oil in the engine 51 is high and the starter motor 56
The load applied to is further increased. Therefore, the starter motor 56 is required to have an output higher than those, and there is a problem that the motor becomes large.

On the other hand, as an engine starting system, there is known a system which employs a so-called inertial starting system in which the crankshaft is first rotated in the reverse direction and then rotated in the forward direction to start the engine. In this inertial starting method, the load at the initial cranking is overcome by using the approaching rotational inertial force,
In comparison with the case where a motor having a lock torque larger than the compression torque of the engine is required in the normal starting method, the output of the starter motor can be small, and the motor can be downsized accordingly. In this method, the higher the average cranking speed of the starter motor, the more effectively the inertial force can be used, and the higher the effect.

However, if such an inertial starting system is adopted in the engine 51 having the power transmission system as described above, the starter motor 56 must also bear the load after the transmission 52, and moreover, the belt type. The friction of the transmission 52 is also large. Therefore, in order to obtain the required cranking rotation speed, it is necessary to increase the output of the starter motor 56, and there is a problem that the advantage of adopting the inertial starting method cannot be obtained.

Further, the battery mounted on a two-wheeled vehicle is generally smaller than that of a four-wheeled vehicle, and the amount of current flowing therethrough is not too much. Therefore, when the starter motor 56 becomes large, the amount of current required for driving the motor cannot be obtained only for the battery which originally has no margin and the charging period is short, so that the battery may be exhausted. In order to prevent this, it is necessary to mount a large battery, but it is not preferable to increase the size of the battery, and the size of a motorcycle is limited.

On the other hand, the starter motor 56 is often used as a generator when the engine is operating. However, since the magnetic force required for power generation is smaller than that required for starting, the amount of power generation is generally excessive. Tend to be.
For this reason, in the motor and the control circuit, various measures have been taken such as suppressing the excessive power generation performance by the field weakening and consuming the excessive power by the resistor. However, as described above, as the motor becomes larger, the amount of power generation also increases, so further measures are required, and not only the motor itself but also the control circuit and the like become large, which runs counter to the demand for smaller and lighter equipment. It becomes a situation. Further, as the amount of waste power increases, the amount of heat generated also increases, and improvement thereof has been desired.

An object of the present invention is to provide a small-sized and low-cost engine starting system which has a small load when starting the engine.

[0013]

SUMMARY OF THE INVENTION An engine starting system of the present invention is a starter motor for starting an engine, which is disposed on one end side of a crankshaft of an engine, and is arranged on the opposite side with the starter motor and the engine sandwiched therebetween. A clutch unit provided with a drive unit connected to the other end of the crankshaft, and a driven unit connected to the drive unit when the drive unit has reached a predetermined rotation speed or more; And a driven pulley connected to the driven portion and a driven pulley connected to the driving pulley via a belt member.

In the engine starting system of the present invention, it is possible to eliminate the belt drive friction of the belt type transmission when the engine is started, and the starter motor having a small output allows the cranking speed higher than the predetermined speed required for starting. It becomes possible to obtain. Therefore, the starter motor can be downsized, and a compact, lightweight, and low-cost engine starting system can be constructed.

Further, due to the miniaturization of the motor, the unbalance between the magnetic force required at the time of starting and the magnetic force required at the time of power generation is also reduced, and the amount of excess power generation can be reduced. Therefore, a device for suppressing power generation performance and consuming excessive power can be downsized and reduced in cost, heat generation can be reduced, and a highly efficient starting power generation system with less loss can be constructed. Become.

On the other hand, in the engine starting system, a motor whose lock torque is smaller than the compression torque of the engine is used as the starter motor, and torque due to inertia energy is added to the torque generated by the starter motor to provide the engine. It is also possible to go over the compression stroke of. In this case, the normal rotation drive of the starter motor may be started at least from the suction process side near the bottom dead center before the compression stroke in the engine.

In the engine starting system, when the engine is started, the starter motor is reversely energized to reversely rotate the crankshaft, and then the starter motor is normally energized to normally rotate the crankshaft. You may do it. As a result, the engine can be started by utilizing the inertial force around the crankshaft, and the starter motor can be further downsized.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory diagram showing a configuration of a power transmission system of a motorcycle to which an engine starting system according to an embodiment of the present invention is applied.

As shown in FIG. 1, in the motorcycle, the power of the engine 1 is a centrifugal clutch (clutch device) 3 and a belt type continuously variable transmission 2 (belt type continuously variable transmission;
Transmission 2) and is transmitted to the rear wheels 4. A 4-cycle gasoline engine is used as the engine 1, and one end of the crankshaft 5 is
A starter motor 6 for starting the engine is attached. A centrifugal clutch 3 is arranged on the other end side of the crankshaft 5, that is, on the opposite side of the starter motor 6 with the engine 1 interposed therebetween. The other end of the crankshaft 5 is connected to the drive unit 10 of the centrifugal clutch 3.

The centrifugal clutch 3 includes a drive unit 10 and a driven unit 1.
Rotation is transmitted by pressing the centrifugal piece 14 composed of 1 and attached to the drive unit 10 against the friction drum 15 of the driven unit 11 by centrifugal force. Here, the rotation is set to be transmitted to the driven unit 11 side when the drive unit 10 reaches 3500 to 4000 rpm.

The driven portion 11 of the centrifugal clutch 3 is the transmission 2
Is connected to the drive pulley 7. This drive pulley 7
Is composed of a fixed pulley 16 and a movable pulley 17. The movable pulley 17 is arranged so as to be movable in the axial direction by a hydraulic device (not shown). By moving the movable pulley 17 in the axial direction, the width of the pulley groove 18 of the drive pulley 7 can be changed.

The drive pulley 7 is a V belt (belt member).
It is connected to the driven pulley 9 by 8. Like the drive pulley 7, the driven pulley 9 is also composed of a fixed pulley 19 and a movable pulley 20, and the width of the pulley groove 21 can be changed by moving the movable pulley 20 in the axial direction. Further, the driven pulley 9 is connected to a drive shaft 12 for driving the rear wheel 4. The drive shaft 12 is connected to the rear wheel 4 via a gear train 13.

Engine 1 equipped with such a power transmission system
When the engine is started, the starter motor 6 is driven by a battery (not shown) as a power source to rotate the crankshaft 5. Here, when the piston is stopped at a position immediately before the compression stroke when the engine is stopped, the compression stroke is immediately entered when the engine is started, so that the rotation speed of the crankshaft 5 does not increase and inertia energy is increased. Torque cannot be obtained. Therefore, the lock torque is the compression torque of the engine 1 (the crankshaft 5 in the compression stroke).
A torque smaller than the torque required to rotate the motor cannot exceed the compression stroke. Therefore, in the system, the engine 1 is temporarily reversed at the time of starting,
The forward drive is started at least before the bottom dead center of the compression stroke, that is, at a position near the suction process. This allows
Inertial energy is stored at the number of revolutions due to running, and this energy is added to the motor torque as rotational torque in the compression stroke,
The starter motor 6 is downsized.

Further, in this system, the starter motor 6 may be reversely energized at the time of engine start, and the crankshaft 5 may be reversed in the explosion stroke. In the explosion stroke, the gas remaining in the combustion chamber is compressed under the condition that the intake valve and the exhaust valve are closed, so that the normal rotation energy due to the compression reaction is accumulated in the combustion chamber. Then, after the crankshaft 5 is reversely rotated to a predetermined position in the explosion stroke, the starter motor 6 is forwardly energized to normally rotate the crankshaft 5. At this time, the positive rotation energy stored by the compression of the gas in the combustion chamber is transferred to the crankshaft 5
The energy of the compression reaction thus released and the rotational energy applied by the starter motor 6 are added to the rotary system.

That is, the inertial energy of the rotary system is rapidly increased from the initial stage of normal rotation due to the compression reaction due to the release of the energy of the gas accumulated by the compression, and the rotary force of the starter motor 6 causes the rotary system to explode. To the compression stroke, the inertial energy gradually increases. Therefore, in the compression stroke, the combined energy of the inertial energy stored in the rotary system and the energy of the starter motor 6 is added to the crankshaft 5. That is, the crankshaft 5 is driven by the rotational torque of the starter motor 6 and the rotational force by the inertia energy accumulated by the reverse rotation. Therefore, the load on the starter motor 6 at the time of starting can be reduced, and a small motor with a small output can be adopted as the starter motor 6 accordingly.

On the other hand, the starter motor 6 rotates the crankshaft 5 at about 800 rpm when the engine 1 is started. In this case, the centrifugal clutch 3 is attached to the other end side of the crankshaft 5, but as described above, the rotation speed at which the clutch is turned on is 3500 rpm.
Therefore, in the operation by the starter motor 6, the centrifugal clutch 3 is not connected, and the drive unit 10 is idling with respect to the driven unit 11. Therefore, the transmissions 2 and below to which the driven portion 11 is connected are separated from the crankshaft 5 when the engine is started, and these loads do not act on the starter motor 6. That is, the starter motor 6 is
Rotation system of engine 1 and drive unit 10 of centrifugal clutch 3
Only the load becomes a load, and the friction of the V belt does not work as a load.

Then, in such a light load state, the starter motor 6 is driven and the crankshaft 5 is rotated. When the engine is started, after the initial compression stroke is overcome, inertial energy is accumulated, so the load in the subsequent compression stroke can easily be overcome, and the spark can be skipped at a predetermined timing to allow the engine 1 Will start.

When the engine 1 is started in this way, the crankshaft 5 rotates at about 1700 to 1800 rpm during idling (a little over 2000 rpm when cold). At this time, the centrifugal clutch 3 remains in the OFF state, but when the throttle valve is opened by the accelerator operation and the rotation speed of the engine 1 increases, the centrifugal clutch 3 is connected and power is transmitted via the transmission 2. The rear wheels 4 are driven. Then, the widths of the pulley grooves 18 and 21 of the drive pulley 7 and the driven pulley 9 are appropriately adjusted according to the engine load, and the gear ratio is controlled.

As described above, in this system, the belt driving friction of the transmission 2 at the time of starting the engine can be eliminated, and the starter motor 6 having a small output can obtain the cranking rotation speed higher than the predetermined rotation speed necessary for the start. It becomes possible. Therefore, the starter motor 6 can be downsized, and a compact, lightweight, and low-cost engine starting system can be constructed.

Further, regarding the operation in the inertial starting system, the friction of the transmission 2 does not become a load at the time of starting, so that a high average cranking speed can be obtained with a motor having a small output. Therefore, it is possible to take advantage of the advantage of the inertial starting method of downsizing the starter motor 6, and it is possible to achieve further downsizing of the motor in combination with the effect of the above-mentioned load reduction. Further, since the load at the time of reverse rotation of the motor is small, the reverse rotation operation and the return time can be shortened quickly, so that it is possible to realize the inertial start operation with a small time lag.

Further, due to the downsizing of the motor, the imbalance between the magnetic force required at the time of starting and the magnetic force required at the time of power generation is also reduced, and the amount of excess power generation can be reduced.
Therefore, a device for suppressing power generation performance and consuming excessive power can be downsized and reduced in cost, heat generation can be reduced, and a highly efficient starting power generation system with less loss can be constructed. Become.

It is needless to say that the present invention is not limited to the above-mentioned embodiment, and can be variously modified without departing from the scope of the invention. For example, in the above-described embodiment, the example in which the centrifugal clutch 3 that performs ON / OFF by utilizing centrifugal force is used as the clutch device has been shown, but instead, other clutch means such as an electromagnetic clutch is applied. It is also possible.

[0033]

According to the engine starting system of the present invention, the starter motor disposed on one end side of the crankshaft of the engine and the other end side of the crankshaft located on the opposite side of the engine from the starter motor are disposed. By providing the installed clutch device and the belt-type continuously variable transmission that is arranged at the rear stage of the clutch device, it is possible to eliminate the belt drive friction of the belt-type transmission when the engine is started, and to reduce the output. With this starter motor, it is possible to obtain a cranking rotation speed higher than a predetermined rotation speed necessary for starting. Therefore, the starter motor can be downsized, and a compact, lightweight, and low-cost engine starting system can be constructed.

Further, due to the downsizing of the motor, the imbalance between the magnetic force required at the time of starting and the magnetic force required at the time of power generation is also reduced, and the amount of excessive power generation can be reduced. Therefore, a device for suppressing power generation performance and consuming excessive power can be downsized and reduced in cost, heat generation can be reduced, and a highly efficient starting power generation system with less loss can be constructed. Become.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a power transmission system of a motorcycle to which an engine starting system according to an embodiment of the present invention is applied.

FIG. 2 is an explanatory diagram showing a configuration of a power transmission system of a motorcycle to which a conventional engine starting system is applied.

[Explanation of symbols]

1 engine 2 Belt type continuously variable transmission (belt type continuously variable transmission) 3 Centrifugal clutch (clutch device) 4 rear wheels 5 crankshaft 6 Starter motor 7 Drive pulley 8 V belt (belt member) 9 Driven pulley 10 Drive 11 Follower 12 drive shaft 13 gear train 14 Centrifugal coma 15 Friction drum 16 fixed pulley 17 Movable pulley 18 pulley groove 19 Fixed pulley 20 Movable pulley 21 pulley groove 51 engine 52 Belt type continuously variable transmission 53 Centrifugal clutch 54 rear wheel 55 crankshaft 56 starter motor 57 Drive pulley 58 V belt 59 Driven pulley 60 drive 61 Follower 62 drive shaft 63 gear train

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yutaka Nosue             Gunma Prefecture Kiryu-shi Hirosawa-cho 1-26-181 Stock             Company Mitsuba F term (reference) 3G084 BA28 CA01 DA02 DA13 EC02                       EC03 FA36

Claims (4)

[Claims] 1. A starter motor for starting an engine, which is arranged on one end side of a crankshaft of an engine, and a starter motor which is arranged on the opposite side of the starter motor with the engine interposed therebetween and is connected to the other end side of the crankshaft. A drive unit, a clutch device including a driven unit connected to the drive unit when the drive unit has reached a predetermined rotational speed, and a drive pulley connected to the driven unit of the clutch device,
An engine starting system comprising: a belt-type continuously variable transmission including the drive pulley and a driven pulley connected via a belt member. 2. The engine starting system according to claim 1, wherein the starter motor is a motor having a lock torque smaller than a compression torque of the engine, and the torque generated by the starter motor is given a torque due to inertia energy. The engine starting system is characterized by surpassing the compression stroke of the engine. 3. The engine starting system according to claim 2, wherein the normal rotation driving of the starter motor is started at least from a suction process side near a bottom dead center before a compression stroke of the engine. . 4. The crankshaft according to claim 3, wherein the starter motor is reversely energized to reversely rotate the crankshaft once when the engine is started, and then the starter motor is forwardly energized to rotate the crankshaft. An engine starting system characterized by rotating the engine forward.