JPH06213279A - Internal combustion engine driven generator - Google Patents

Abstract

PURPOSE:To provide a device which can decrease vibration without enlarging the size of an internal combustion engine, in an internal combustion engine driven generator for power generation. CONSTITUTION:Balance shafts 25, 28 having unbalance mass are provided in a step-up-gear 9 by which the speed of an internal combustion engine is increased and transmitted to a generator. Inertia force and inertia moment generated by the internal combustion engine are cancelled with centrifugal force generated by the unbalance mass of the balance shafts, so as to decrease vibration of the whole device. At this time, there is no necessity to change the design of the cylinder block of the internal combustion engine, and hence the customary engine can be used as it is.

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 drive generator including a generator and an internal combustion engine for driving the generator, and more particularly to a reciprocating internal combustion engine.

[0002]

2. Description of the Related Art In a reciprocating internal combustion engine, inertial force is generated by the reciprocating mass of a piston or the like. This inertial force causes the engine to vibrate, which causes problems such as deterioration of durability of the engine and generation of noise due to transmission of this vibration. When such a reciprocating internal combustion engine is used as a drive source for a vehicle or the like, there is a problem that vibrations are transmitted to the vehicle body and noise called muffled noise emitted from the steel plates constituting the vehicle body is generated.

As a countermeasure against this, the cylinder arrangement, crank angle phase, and ignition timing are set so that the number of cylinders of the engine is increased and the inertial forces generated in the plurality of cylinders are canceled out as much as possible. In addition, by rotating one or more balance shafts having an unbalanced mass with respect to the rotation axis, the inertial force and the inertial couple are canceled, and the direction of the inertial force is changed to transmit the force to the vehicle body. The vibration that occurs is reduced.

In particular, in the case of an in-line four-cylinder engine, which is widely used in small passenger cars and the like, the engine rotational speed of 2 is generated in each cylinder.
Since the inertial force of the double frequency, that is, the phase of the so-called secondary inertial force is aligned, the effect of increasing the number of cylinders as described above does not appear. In order to prevent this secondary vibration, a technique is known in which two balance shafts that rotate at a speed twice as high as the engine speed are provided and they are rotated in reverse. For example, JP-A-4-
As a conventional example, Japanese Patent Laid-Open No. 102744 discloses an engine in which two balance shafts are arranged laterally of a cylinder block and are rotated in reverse at twice the engine speed. Further, the above-mentioned publication discloses a technique in which an alternator is built in a side wall of a cylinder block, an unbalanced mass is provided on a shaft of the alternator, and the balance shaft is substituted.

[0005]

An alternator (generator) disclosed in the prior art is a generator for supplying electric power to electric parts such as a vehicle engine ignition system and a lamp / fan. It can be small. However, when a large-sized generator must be used, it cannot be built in the side wall of the cylinder block, and therefore the method of the conventional example cannot be adopted.

As a case where it is necessary to use such a large generator, for example, the generator is driven by an internal combustion engine, and the motor is driven by the electric power generated by this.
There is a case such as a hybrid electric vehicle that obtains a driving force for driving the vehicle. In this case, there is a problem that the generator cannot be built in the side wall of the cylinder block as described above because the generator is large.

Furthermore, when a balancer is provided in the generator, the distance between the point of action of the inertial force of the engine and the point of action of the balance force due to the rotation of the balancer becomes too large, and the balancer is generated by the moment generated by these forces. There was also a problem that the effect of was reduced.

The present invention has been made to solve the above-mentioned problems, and an internal combustion engine drive power generation in which the inertial force generated by the engine is canceled without providing a balance shaft on the side wall of the cylinder block or in the generator. The purpose is to provide a machine.

[0009]

In order to achieve the above-mentioned object, an internal combustion engine drive generator according to the present invention is provided with an internal combustion engine in a speed increaser for increasing the driving force of the internal combustion engine and transmitting it to the generator. Two balance shafts were provided, rotating in opposite directions at twice the rotational speed and having an unbalanced mass with respect to the axis of rotation.

[0010]

The present invention has the above-mentioned structure, and cancels the inertial force or the inertia couple generated by the engine by the inertial force generated by the unbalanced mass of the balance shaft. This can reduce overall vibration of the internal combustion engine and the generator.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a hybrid electric vehicle in which a motor is rotated by electric power generated by a generator driven by an internal combustion engine to rotate a vehicle. The vehicle 1 can be moved forward and backward by front wheels 3 driven by an AC motor 2 via a reduction gear 4.
Electric power is supplied to the AC motor 2 from a battery 6 via an inverter 5. Further, a generator 8 driven by an internal combustion engine 7 for charging the battery 6 is mounted. In the present embodiment, as the internal combustion engine 7, a reciprocating internal combustion engine having four in-line cylinders is used. Normally, the most efficient operating speeds of the generator and the reciprocating internal combustion engine are different, so the rotation of the internal combustion engine 7 is increased by the speed increaser 9 to drive the generator 8. These internal combustion engine 7 and generator 8 are
An electronic control unit (EC that monitors the operating status of the inverter 5
U) 10 controls the operation.

FIG. 2 shows an internal combustion engine 7, a generator 8 and a gearbox 9.
It is a side view of the assembled state with. The speed increaser 9 is attached to the rear of the cylinder block of the internal combustion engine, and the generator 8 is attached to the rear of the cylinder block. As shown in the figure, the internal combustion engine 7 of this embodiment is an in-line 4-cylinder internal combustion engine having four pistons 11. The most common ignition sequence for this in-line 4-cylinder engine is the first cylinder (# 1) →
It is No. 3 (# 3) → No. 4 (# 4) → No. 2 (# 2), and the crank arrangement is 0 ° (# 1) in order from the first cylinder.
→ 540 ° (# 2) → 180 ° (# 3) → 360 ° (#
4). Also in this embodiment, the above-mentioned ignition sequence and crank arrangement are adopted. In the case of such an in-line four-cylinder engine, vibration having a cycle of twice the engine speed, that is, secondary vibration is added in the direction of the cylinder axis generated in each cylinder, and a force four times the inertial force per cylinder is added. Occurs.
The phase of this vibration is the phase in which the amplitude is maximum when any piston is at top dead center.

FIG. 3 is a view showing a cross section taken along the line AA of FIG.
FIG. 4 is a plan view thereof. The drive gear 20 rotatably supported by the bearings 18 and 19 has a spline shaft 20a that fits into a spline hole provided at the center of a flywheel (not shown) of the internal combustion engine. Is first transmitted to the gear 20. The drive gear 20 is a driven gear 21 directly connected to the rotor shaft of the generator 8.
The driving gear 20 and the driven gear 21 are accelerated by the gear ratio to drive the generator 8. This gear ratio is determined by the most efficient operating speed of each of the internal combustion engine 7 and the generator 8. In the case of the present embodiment, the speed-up action is obtained by one set of gears, but if it is desired to increase the speed-up ratio, it is possible to use two or more sets of gears to increase the speed. is there.

A characteristic of this embodiment is that the drive gear 20 meshes with the driven gear 21 as well as the first balance shaft gear 22 and the idle gear 23 to rotate them. First balance shaft gear 22
And the gear ratio of the drive gear 20 is set to 1/2,
The first balance shaft gear 22 rotates at the number of rotations of the drive gear 20, that is, twice the speed of the internal combustion engine 7. The first balance shaft gear 22 has bearings 26, 2
A balance shaft 25, which is rotatably supported by 7, is coaxially fixed. The balance shaft 25 has a weight portion 25a that has an unbalanced mass, and when the balance shaft 25 rotates, a centrifugal force is generated in the weight portion 25a.

On the other hand, the idle gear 23, which is another gear driven by the drive gear 20, is further meshed with the second balance shaft gear 24. Drive gear 20
And the second balance shaft gear 24 have a speed ratio of 1/2, which is the same as that of the first balance shaft gear 22.
The number of teeth of each gear is set. A second balance shaft 28, which is rotatably supported by bearings 29 and 30, is also coaxially fixed to the second balance shaft gear 24. The second balance shaft 28 also has a weight portion 28a having an unbalanced mass, and a centrifugal force is generated when the second balance shaft 25 rotates.

The above two balance shafts 25, 28
Are configured to reverse each other. Further, each of the weight portions 25a and 28a is arranged so as to be located at the highest position in the cylinder axial direction when any one of the four cylinders is at the top dead center. With the arrangement and rotation direction as described above, the centrifugal forces generated by the weight portions 25a and 28a are canceled in the direction orthogonal to the cylinder axis, and are added in the cylinder axis direction. As can be seen from this, the centrifugal force generated by one weight portion needs to be designed to be half the secondary inertial force generated by the engine.

As described above, in the present embodiment, the speed increasing device 9 is used.
Although the balance shaft is provided inside, the arrangement may be provided inside the generator 8. However, in this case, the following problems occur. As shown in FIG. 2, the inertial force F ₁ of the internal combustion engine
Is the center of vibration of the four cylinders, that is, the center of the cylinder block. On the other hand, the point of application of excitation force due to the balance shaft in order to fully offset the inertia force F _1, it is necessary to match the center of the inertial force F _1. If it is difficult to provide the balance shaft on the side wall of the engine, it is desirable that the point of action be as close to this point as possible. When the balancer shaft is provided in the speed increaser 9, the exciting force is F _{2 in the} figure. In this case, since it is deviated from the inertial force F ₁ , the axes of the cylinder and the crankshaft are orthogonal to each other. A couple of magnitude (F ₁ × L ₁ ) is generated around (hereinafter referred to as Y axis). When the balance shaft is provided in the generator 8, the exciting force is almost F _{3 in the} figure, and the magnitude of the generated couple is F ₁ × L ₂ . Since these couples cannot be canceled unless a new balance mechanism is provided, it is desirable that the couple be as small as possible. Therefore, it is understood that it is better to provide the balance shaft in the speed increaser 9 than in the generator 8.
Of course, it is preferable to install it on the side wall of the cylinder block, but in this part, intake manifold, exhaust manifold, catalytic converter as well as alternator, auxiliary parts such as compressor for air conditioner, etc. are often arranged. Considering the interference with the engine, the size of the entire engine will increase. This is an element that we want to avoid when considering mounting on a vehicle. Further, even when considering sharing a cylinder block with a vehicle model without a balance mechanism, the above-described configuration is an element to avoid. Therefore, it can be seen that the provision of the balance shaft in the above-mentioned gearbox is a harmonious arrangement that can satisfy both the demands for downsizing and low vibration of the engine. Further, since there is no need to change the cylinder block, the cylinder block that has been conventionally produced can be used, and there is no need to newly create a cylinder block as an internal combustion engine cylinder block for a hybrid electric vehicle. Commonality can be achieved, and low-cost production becomes possible.

The moment about the Y axis has been described above, but the moment about the crank axis will be described below.

In order to cancel the component of the centrifugal force generated by the two weight portions 25a and 28a in the cylinder axis direction with the inertial force of the engine, the balance shafts 25 and 28 are equidistant from the crankshaft in the Y axis direction. Need to be located. If the balance shafts 25, 28 are arranged at the same height in the cylinder axis direction, the Y-axis direction components of the centrifugal forces generated by the two weight portions 25a, 28a cancel each other out, and no moment is generated. However, a technique for shifting the position of the balance shaft in the cylinder axis direction is already known for the purpose of canceling out an inertial couple of force around the crankshaft due to the exciting force applied to the cylinder side wall by the piston. That is, as shown in FIG. 3, the moment generated by the balance shaft arranged with a shift of d and the inertia couple generated by the aforementioned engine are offset. It is also known that, in order to completely cancel out the inertia couple and the moment due to the balance shaft, the d may be the length of the connecting rod.
The balance shaft of this embodiment is also arranged in consideration of this.

The case where an in-line 4-cylinder internal combustion engine is used has been described above, but the present invention is not limited to this, and may be applied to, for example, a primary couple balancer of a V-6 cylinder engine.

[0022]

As described above, according to the present invention, the balance shaft can be arranged without increasing the size of the internal combustion engine body. As a result, it is possible to provide an internal combustion engine driven generator that is both compact and low in vibration.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a schematic configuration of a hybrid electric vehicle.

FIG. 2 is a diagram showing a state in which an internal combustion engine, a generator, and a speed increaser are assembled.

FIG. 3 is a view showing a configuration of a speed increaser, and is a front sectional view of the speed increaser as seen from the internal combustion engine side.

FIG. 4 is a diagram showing a configuration of a speed increaser, and particularly a plan sectional view thereof.

[Explanation of symbols]

 7 Internal Combustion Engine 8 Generator 9 Gearbox 20 Drive Gear 22 First Balance Shaft Gear 23 Idle Gear 24 Second Balance Shaft Gear 25 First Balance Shaft 28 Second Balance Shaft

Claims (1)

[Claims] 1. An internal combustion engine drive generator driven by an internal combustion engine via a speed increaser, which is provided in the speed increaser and rotates in directions opposite to each other at a speed twice as high as an internal combustion engine speed. Having two balance shafts having an unbalanced mass with respect to the rotation axis of the internal combustion engine driven generator.