JP2001098969A - Gas engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a low engine speed without using a fly wheel. SOLUTION: A rotating speed holding device 5 is composed of a motor 12, a generator 13, a switch 16, an angular velocity detector 14, a controller 15, a battery 17 and the like. When an angular velocity gets smaller than a prescribed value, the battery 17 is connected to the motor 12, the motor 12 is thereby rotated by electric power of the battery 17 to make the engine speed constant, based on a signal from the detector 14. When the angular velocity gets higher than the prescribed value, the battery 17 is connected to the generator 13 to accumulate electric power generated in the generator 13, and a generation load is applied thereby to the engine to make the speed constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas engine which does not cause so-called engine stall even at low speed rotation.

[0002]

2. Description of the Related Art Conventionally, gas engines have been used in gas heat pump devices, automobiles and the like. Such an engine is an internal heat engine using gas as a fuel, and various engines such as two cylinders and four cylinders have been proposed. The principle is based on four cycles of compression, explosion, exhaust, and intake of gas as a fuel.

[0003] However, such a gas engine is used for about 80 hours.
If the rotation speed is less than 0 rpm, the engine will stall. If the gas engine is used to compress the refrigerant and perform air conditioning, there is a demand to expand the operating range of air conditioning by performing lower speed rotation. Was difficult to have.

That is, as described above, the engine is provided with the intake air,
It keeps rotating while repeating the cycle of compression, explosion, exhaust, but basically power is generated only at the time of explosion, intake,
In the process of compression and exhaust, it is necessary to apply force to the piston.

[0005] Generally, the force at the time of intake or the like is supplied by inertia of a rotating shaft or the like. However, if the rotation speed is reduced and the time interval until explosion is increased, sufficient intake force,
Unable to supply compression force and exhaust force, especially when a large force is required as in the compression process, if sufficient power is not supplied, rotation stops before explosion and engine stalls .

Such an engine stall tends to occur in a low-cylinder engine, and is particularly remarkable in a gas engine used for a gas heat pump.

Therefore, it is conceivable to attach a flywheel to the engine to increase the inertial force so that the engine does not stall even at low speed rotation.

[0008]

However, when a flywheel is used, it naturally takes a long time to reach a constant speed rotation, which makes it impossible to start up smoothly and increases the weight.

Accordingly, an object of the present invention is to provide a gas engine capable of low-speed rotation without using a flywheel.

[0010]

According to a first aspect of the present invention, there is provided a gas engine that generates rotational power using gas as fuel, when the rotational speed of the engine is lower than a preset rotational speed. A rotating speed holding device for applying power to the engine and generating a load when the rotating speed becomes higher than a preset rotating speed, thereby applying a load to the engine and keeping the rotating speed substantially constant; It is characterized by low-speed rotation without using wheels.

According to a second aspect of the present invention, the rotation speed holding device includes a motor and a generator connected to the rotating shaft of the engine, a storage device, and a switch for selectively switching connection between the storage device and the motor or the generator. And an angular velocity detector for detecting the angular velocity of the engine; and, based on a signal from the angular velocity detector, when the angular velocity becomes smaller than a predetermined value, connect the battery to the motor and connect the motor with the power of the battery to power the motor. The engine is rotated to keep the rotation speed of the engine constant, and when the angular speed becomes larger than a predetermined value, the power is generated by the engine by connecting the battery and the generator and storing the power generated by the generator in the battery. Since it is configured with a controller that applies a load and keeps the rotation speed constant,
The low-speed rotation can be performed without using a flywheel.

According to a third aspect of the present invention, the rotation speed holding device includes a motor connected to a rotation shaft of the engine, and a capacitor connected to the motor, and the rotation speed holding device is configured to control the rotation speed of the motor rotated by the capacitor. When the rotation speed of the engine increases, the motor works as a generator to store the generated power in a capacitor, and at that time, the motor acts as a load on the engine to keep the rotation speed of the engine substantially constant. When the rotation speed of the engine is lower than the rotation speed of the motor that rotates by the electric power from the motor, the power of the motor is applied to the engine so that the rotation speed of the engine is kept substantially constant, without using a flywheel. It is characterized by low-speed rotation.

According to a fourth aspect of the present invention, the rotational speed holding device is provided with a motor and a generator connected to a rotating shaft of the engine, a capacitor, and a connection between the capacitor and the motor or a connection between the capacitor and the generator. It has a switch for switching and a switch control unit that controls the switch in phase synchronization with the rotation of the rotating shaft, and the motor and the generator are alternately switched according to the phase range of the rotating shaft to make the rotation speed of the engine substantially constant It is characterized in that it can be kept at a low speed without using a flywheel.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a gas engine according to the present invention.

The gas engine 10 is provided with a rotation speed holding device 5. When the instantaneous rotation speed of the gas engine 10 decreases, a force is applied to increase the rotation speed. When the actual rotation speed increases, a force is taken out (by applying a load) to reduce the rotation speed so that the rotation speed is kept constant.

That is, the rotation speed holding device 5 includes a motor 12 for assisting the rotation of the gas engine 10,
, An angular velocity detector 14 for detecting the angular velocity of the gas engine 10, and comparing the angular velocity from the angular velocity detector 14 with a preset reference value to output a switch switching signal in a predetermined case. A controller 15, a switch 16 for switching by a signal from the controller 15,
A power supply 17 supplies the electric power to the motor 12 and stores the electric power generated by the generator 13.

FIG. 2 shows an angular velocity line (solid line) L in the four-cylinder gas engine 10 and a constant angular velocity line (dotted line) K when this is controlled by the rotation speed holding device 5 according to the present invention.
FIG. Note that point B in the figure indicates an explosion point.

If the gas engine 10 explodes, the rotating shaft 1
Due to the inertia force of the compressor 1 and the compressor (not shown) connected thereto, the rotation speed does not immediately rise and a time lag occurs to reach the maximum angular velocity state (point P).

From this point P to the next explosion B, the angular velocity is decreasing while the explosion increases the angular velocity.

Therefore, the angular velocity of the gas engine 10 is detected by the angular velocity detector 14, and when this angular velocity becomes smaller than a predetermined reference value (corresponding to the radius of the dotted line K in FIG. 2) (in FIG. And outputs a switch switching signal.

As a result, the switch 16 is switched to supply electric power from the battery 17 to the motor 12, and the rotation speed of the gas engine 10 is maintained by the power of the motor 12.

On the other hand, when the detected angular velocity of the gas engine 10 becomes larger than a preset reference value (a hatched area in the lower left part of FIG. 2), the controller 15 outputs a switch switching signal, and outputs a signal to the storage device 17 and the generator. 13 is connected.

As a result, the electric power generated by the generator 13 is stored in the storage device 17, and the angular speed of the gas engine 10 is reduced due to the load generated by the power generation, and the rotation speed is maintained.

As described above, the rotation speed of the gas engine 10 can be kept constant by the rotation speed holding device 5 without providing a flywheel.
Can be operated at a low rotation speed.

Then, for example, such a gas engine 1
In the case of performing air conditioning by rotating the compressor at zero, the control range can be widened and the operation efficiency can be improved.

In the above description, the motor 12 and the generator 1
3 are provided separately, but the present invention is not limited to this, and the motor 12 and the generator 13
Can also be used, and in such a case, the switch 16, the angular velocity detector 14, and the controller 15 can be omitted.

For example, when the angular velocity of the gas engine 10 is high and the motor 12 is generating electric power, the electric power is stored in the electric storage 17. On the other hand, the gas engine 10
When the angular velocity of the motor becomes smaller and the voltage of the electric power generated by the motor 12 becomes smaller than the voltage of the electric storage device 17, the electric power is supplied from the electric storage device 17 to the motor 12 so that the motor 12 keeps the rotation speed of the gas engine 10 constant. It works like so.

In the above description, the case where the angular velocity is detected and the switching control between the battery 17 and the generator 13 or the motor 12 is performed has been described. However, as can be understood from FIG. 2, the angular velocity periodically fluctuates. Therefore, the generator 13 and the motor 12 may be switched in synchronization with this cycle.

FIG. 3 is a diagram showing the respective operating regions when the motor 12 and the generator 13 are switched in synchronism with the cycle in the case of two cylinders and FIG. 4 in the case of four cylinders. .

In these figures, in the area M, the capacitor 17
Supplies electric power to the motor 12 to increase the rotation speed of the gas engine 10 by the motor 12,
3, the power is supplied to the battery 17 and the power is stored in the battery 17, whereby the rotation speed of the gas engine 10 is suppressed.

Even with such a configuration, the rotation speed of the gas engine can be kept substantially constant.

[0032]

As described above, according to the first aspect of the present invention, when the rotation speed of the engine is lower than the predetermined rotation speed, the engine is powered, and the rotation speed is set to the predetermined rotation speed. When the rotation speed is increased, a load is applied to the engine by generating power, and the rotation speed holding device for maintaining the rotation speed substantially constant is provided, so that low-speed rotation can be performed without using a flywheel.

According to the second aspect of the present invention, the rotational speed holding device selectively connects the motor and the generator connected to the rotating shaft of the engine, the capacitor, and the connection between the capacitor and the motor or the generator. A switch for switching, an angular velocity detector for detecting an angular velocity of the engine, and, based on a signal from the angular velocity detector, when the angular velocity becomes smaller than a predetermined value,
By connecting the battery and the motor, the motor is rotated by the electric power of the battery to keep the rotation speed of the engine constant, and when the angular speed becomes larger than a predetermined value, the battery is connected to the power generator to generate the electric power. Since the power generated by the machine is stored in a battery to apply a load of power generation to the engine so as to keep the rotation speed constant, low-speed rotation can be performed without using a flywheel.

According to the third aspect of the present invention, the rotational speed holding device comprises: a motor connected to the rotating shaft of the engine;
A motor connected to the motor, and when the rotation speed of the engine is higher than the rotation speed of the motor rotated by the storage device, the motor operates as a generator to store the generated power in the storage device; Acts as a load on the engine to keep the rotation speed of the engine substantially constant, and when the rotation speed of the engine becomes smaller than the rotation speed of the motor rotating by the electric power from the battery, the power of the motor is applied to the engine. As a result, the rotational speed of the engine is kept substantially constant, so that low-speed rotation can be performed without using a flywheel.

According to the fourth aspect of the present invention, the rotational speed holding device comprises a motor and a generator connected to the rotating shaft of the engine; a capacitor; and a connection between the capacitor and the motor or a connection between the capacitor and the generator. It has a switch for switching the connection and a switch control unit for controlling the switch in phase synchronization with the rotation of the rotating shaft, and the motor and the generator are alternately switched according to the phase range of the rotating shaft to substantially reduce the rotational speed of the engine. Since it is kept constant, low-speed rotation can be performed without using a flywheel.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a gas engine applied to the description of an embodiment of the present invention.

FIG. 2 is a diagram illustrating the operation of a rotation speed holding device in the case of four cylinders.

FIG. 3 is a diagram illustrating the operation of a rotation speed holding device in the case of two cylinders.

FIG. 4 is a diagram for explaining the operation of the rotation speed holding device in the case of four cylinders.

[Explanation of symbols]

 Reference Signs List 5 rotation speed holding device 10 gas engine 11 rotation shaft 12 motor 13 generator 14 angular velocity detector 15 controller 16 switch 17 battery

Claims (4)

[Claims] In a gas engine that generates rotational power using gas as fuel, power is applied to the engine when the rotational speed of the engine is lower than a preset rotational speed, and the rotational speed is higher than the preset rotational speed. A gas engine provided with a rotation speed holding device for applying a load to the engine by generating power so as to keep the rotation speed substantially constant. 2. A motor connected to a rotating shaft of an engine, wherein the rotating speed holding device is connected to a rotating shaft of the engine similarly to the motor; a capacitor; a capacitor; A switch for selectively switching connection to the motor, an angular velocity detector for detecting an angular velocity of the engine, and, based on a signal from the angular velocity detector, when the angular velocity becomes smaller than a predetermined value, the battery and the motor And the motor is rotated by the electric power of the capacitor to keep the rotation speed of the engine constant, and when the angular speed becomes larger than a predetermined value, the capacitor and the generator are connected to generate electricity by the generator. 2. The gas generator according to claim 1, wherein the controller is configured to store the generated electric power in a storage device to apply a load of electric power generation to the engine so as to keep the rotation speed constant. Jin. 3. The engine according to claim 1, wherein the rotation speed holding device has a motor connected to a rotation shaft of the engine, and a storage device connected to the motor. Is larger, the motor works as a generator to store the generated power in the battery, and at that time, the motor acts as a load on the engine to keep the rotation speed of the engine substantially constant, 2. The system according to claim 1, wherein when the rotation speed of the engine is lower than the rotation speed of the motor rotated by electric power, the power of the motor is applied to the engine to keep the rotation speed of the engine substantially constant. The described gas engine. 4. A motor connected to a rotating shaft of an engine, wherein the rotating speed holding device is connected to a rotating shaft of the engine similarly to the motor, a power storage device, and a connection between the power storage device and the motor. Or a switch for switching the connection between the electric storage device and the generator, and a switch control unit for controlling the switch in phase with the rotation of the rotating shaft, and the motor and the generator alternate with each other according to the phase range of the rotating shaft. 2. The gas engine according to claim 1, wherein the gas engine is switched so as to keep the rotation speed of the engine substantially constant.