JPH057485Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] This invention relates to a fuel supply system for a gas engine, and is particularly designed to prevent unnecessary waste fires from occurring, and to
The present invention relates to a fuel supply device for a gas engine that can prevent gas explosions and the like from occurring, prevent damage to the gas engine and its peripheral parts, and improve safety.

[Conventional technology]

In addition to gasoline and light oil for diesel engines, there are also gas engines that use liquefied gases such as LPG as fuel. LPG has low fuel costs, mixes well with air, and burns completely.
It has various advantages such as less air pollution due to exhaust gas. A gas engine is disclosed in, for example, Japanese Patent Laid-Open No. 60-53652. The gas engine described in this publication uses a valve control mechanism to adjust the valve control mechanism so that when the intake throttle valve opens, fuel is supplied that matches the opening of the intake throttle valve. The purpose is to ensure that the engine is started easily and to avoid forcing the driver to impose restrictions on starting and making it difficult to operate the accelerator.

[Problem that the invention attempts to solve]

By the way, in a conventional gas engine, when the start signal is turned ON, the carburetor throttle valve opens and the starter is driven, and at the same time, the fuel supply valve of the fuel supply system operates. However, for ignition timing control, for example, the start signal
If the ignition system is set to stop operating for two seconds after turning on, the fuel supply valve will operate when the start signal turns on, supplying flammable gas as fuel. If the fuel chamber and exhaust system of a gas engine are filled with flammable gas, and ignition is performed in a state filled with flammable gas, a gas explosion will occur around the gas engine, and the gas engine and its surrounding parts may be damaged. It was damaged and dangerous. At this time, the outflow of flammable gas in 2 seconds is about 3000 c.c. In addition, in a four-cycle gasoline engine, ignition is performed once per revolution of the crankshaft to blow away the flames. This ignition is not a problem with this 4-stroke gasoline engine, but with a gas engine,
Since gas fuel is highly flammable, there is an inconvenience that unnecessary combustion occurs due to abandoned fire.

[Purpose of the invention] Therefore, in order to eliminate the above-mentioned inconvenience, the purpose of this invention is to detect a predetermined stroke based on the engine rotational speed state after a predetermined time has elapsed from the start of the starter in a four-stroke gas engine. By installing a control unit that operates the ignition system to ignite once every two revolutions of the crankshaft, and operates the fuel supply system almost simultaneously with the operation of the ignition system to supply gas fuel to the gas engine, it is possible to In addition to preventing the occurrence of gas and avoiding unnecessary combustion, it also avoids the unnecessary supply of gas fuel, prevents gas explosions, etc., and prevents damage to the gas engine and its surrounding parts, thereby increasing safety. The object of the present invention is to realize a fuel supply system for a gas engine that can improve the performance.

[Means for solving problems]

In order to achieve this purpose, this invention is a gas engine fuel supply system that supplies gas fuel to a four-cycle gas engine, and after a predetermined period of time has elapsed from the start of the starter, a predetermined stroke is performed depending on the engine speed state. A control unit is provided that detects the gas and operates an ignition system to perform ignition once every two revolutions of the crankshaft, and operates a fuel supply system substantially simultaneously with the operation of the ignition system to supply gas fuel to the gas engine. It is characterized by

[Effect]

According to the configuration of this invention, in a 4-cycle gas engine, a predetermined stroke is detected according to a stable engine rotational speed state after a predetermined period of time has elapsed from the start of the starter, and ignition is performed for two revolutions of the crankshaft. Since this is done once, it is possible to prevent the occurrence of waste fires and eliminate unnecessary combustion. Furthermore, when starting a gas engine, even if the start signal turns ON and the starter is driven, the fuel supply system operates almost simultaneously with the ignition system to supply fuel, so fuel may not be supplied unnecessarily. Therefore, fuel will not fill the combustion chamber or exhaust system of the gas engine before ignition and will not flow out to the outside. This prevents the occurrence of a gas explosion or the like at the time of starting ignition, prevents damage to the gas engine and its peripheral parts, and improves safety.

〔Example〕

Embodiments of this invention will be described in detail and specifically below based on the drawings.

1 to 7 show examples of this invention. In the figure, 2 is a four-cycle gas engine that uses liquefied gas, such as LPG, 4 is a carburetor, 6 is a throttle valve of the carburetor 4, 8 is a vent lily portion of the carburetor 4, 10 is an intake manifold, and 12 is a 14 is an ignition system, 16 is a starter, and 18 is a fuel tank. This fuel tank 1
One end side of a first fuel supply pipe 20 is connected to 8, and a primary regulator 22 and a fuel supply valve 24 of the fuel supply system are provided in the middle of this first fuel supply pipe 20 in order from the side closest to the fuel tank 18. There is. The other end of the first fuel supply pipe 20 is connected to a secondary regulator 26 . This secondary regulator 2
6 is connected to one end side of a second fuel supply pipe 28,
The other end of the second fuel supply pipe 28 is connected to the bench lily portion 8 of the carburetor 4 .

The throttle valve 6 is opened and closed by a stepping motor 32 operated by a command signal from a control section 30.

An ignition signal detection mechanism 34 is in communication with the control section 30 . The ignition signal detection mechanism 34 includes a flywheel 36 fixed to a crankshaft (not shown) and a pulse generating coil 38 fixed to another part of the gas engine 2. That is, the ignition signal detection mechanism 34 includes a protrusion 36a and a notch 3 formed on the outer periphery of the flywheel 36.
6b passing through the position of the pulse generating coil 38, an electromotive force is generated in the pulse generating coil 38 due to a change in the amount of magnetic flux, and this electromotive force is output to the control section 30 as an ignition signal. Specifically, as shown in FIG. 2, a protrusion 36 formed on the flywheel 36 at the position of the pulse generating coil 38
When a moves to the notch 36b, the pulse voltage waveform generated in the pulse generating coil 38 becomes a positive pulse (indicated by A in FIG. 4), and on the other hand, as shown in FIG. When the notch 36b formed in the flywheel 36 moves to the protrusion 36a, the pulse voltage waveform generated in the pulse generating coil 38 becomes a negative pulse (indicated by B in FIG. 4). Therefore, the control section 30 controls the operation of the ignition mechanism 14 in response to the ignition signal from the ignition signal detection mechanism 34. The starter 16 is also connected to the control unit 30 .

Further, the control unit 30 detects a predetermined stroke based on the engine speed state after a predetermined period of time (for example, 2 seconds) has elapsed since the start of the starter 16, and controls the ignition to occur once every two revolutions of the crankshaft (not shown). At the same time, the ignition mechanism 14 of the ignition system is differentially operated so that the ignition mechanism 14 is activated, and the fuel supply valve 24 of the fuel supply system is activated almost simultaneously with the operation of the ignition mechanism 14, that is, immediately before the ignition mechanism 14 is activated or at the same time as the ignition mechanism 14 is activated. It operates to supply gas fuel to the gas engine 2. In addition, the code|symbol 40 is an adjustment tool.

Next, the operation of this embodiment will be explained based on the flowchart of FIG. 5 and the timing chart of FIG. 6.

When starting the gas engine 2, when the start signal turns ON in step 102 (a in Figure 6)
(indicated by position), first in step 104 the vaporizer 4
is opened, that is, the throttle valve 6 is opened. Next, in step 106, it is determined whether the opening degree of the throttle valve 6 is 10 degrees or not. Step when throttle valve 6 opening is less than 10 degrees
If 106 is NO, the process returns to step 104 and the determination of the opening state of the throttle valve 6 is continued. If the opening degree of the throttle valve 6 is 10 degrees and step 106 is YES, the starter 16 is turned on and started in step 108 (as shown by position b in Fig. 6), and then step 108 is started.
The timer is started at 110. Next, while maintaining the above-mentioned state, it is determined in step 112 whether or not a predetermined time of 2 seconds has elapsed. The predetermined time of 2 seconds has not elapsed and step 112 is not completed.
If NO, the process returns to step 110 to continue determining the time elapsed state. If 2 seconds have passed and step 112 is YES, step 114 is executed.
It is determined whether or not a negative pulse, which is an ignition signal from the ignition signal detection mechanism 34, has been input. Step 114 is completed without inputting a negative pulse.
In the case of NO, this judgment state is continued. On the other hand, a negative pulse is input and step 114 is YES.
In this case, the engine rotational speed X at that time is detected in step 116.

Then, in step 118, it is determined whether a negative pulse, which is an ignition signal, has been input again. Step 118 is completed without inputting a negative pulse.
In the case of NO, this judgment state is continued. On the other hand, a negative pulse is input and step 118 is YES.
In this case, in step 120, the engine rotational speed Y at that time is detected.

Next, in step 122, it is determined whether the engine rotation speed X detected earlier is larger than the engine rotation speed Y detected later. If the previously detected engine speed X is larger than the later detected engine speed Y and step 122 is YES, the later detected engine speed Y is
It is detected that is an explosion stroke, which is a predetermined stroke. This is because the engine speed during the intake stroke is higher than the engine speed during the explosion stroke in a state where ignition is not performed and no explosion occurs.
Therefore, the engine is not ignited at the next negative pulse, but is ignited every other rotation of the crankshaft from the second negative pulse. This is to prevent discarded fires by igniting once every two rotations of the crankshaft in a 4-cycle gas engine.
On the other hand, the previously detected engine speed X is smaller than the detected engine speed and step 122 is NO.
In this case, it is detected in step 126 that the engine speed Y is in the intake stroke. Therefore,
Ignition occurs every other revolution of the crankshaft from the time the next negative pulse is input. In this case, as described above, in a 4-cycle gas engine, ignition is performed once every two revolutions of the crankshaft, thereby preventing discarded fire.

As described above, once the ignition rotation determination rotation speed has been captured once every two rotations of the crankshaft (shown in the S area in FIG. 6), the fuel supply valve 24 is opened in step 128 to supply fuel. is supplied from the carburetor 4 to the gas engine 2, and the step
At 130, turn on the ignition power and turn on the ignition mechanism 1.
4 to ignite. That is, the fuel supply valve 24 is operated substantially simultaneously with the operation of the ignition mechanism 14 (as shown at position c in FIG. 6).

Then, in step 132, it is determined whether the engine speed is 900 rpm or more. If the engine speed is less than 900 rpm and step 132 is NO, the engine speed determination state is continued. On the other hand, if the engine speed is 900 rpm or more, step 132
If is YES, startup is completed in step 134. At this time, the opening degree of the throttle valve 6 becomes greater than 10 degrees, and the starter 16 stops operating (as shown by position d in FIG. 6).

As a result, when starting the gas engine 2, the fuel supply valve 24 is stopped for a predetermined period of time from when the starter signal is turned on until ignition is performed, so that fuel is not supplied unnecessarily, and a gas explosion or the like occurs at the time of ignition. This prevents damage to the gas engine 2 and its peripheral parts and improves safety. Further, since fuel is not supplied in vain, fuel consumption can be reduced. In addition, after a predetermined period of time (2 seconds) has elapsed since the start of the starter 16, a predetermined stroke is detected based on the engine speed state, and ignition is performed once every two revolutions of the crankshaft, so that the engine can maintain a stable predetermined stroke. In addition to accurately detecting the rotational speed, it is possible to prevent waste fire from occurring and eliminate unnecessary combustion.

Note that FIG. 7 shows voltage waveforms (loads) at various parts of the starter 16 when the gas engine 2 is started. In FIG. 7, the voltage applied to the starter 16 is E (filter 50Hz) [V], the current flowing through the starter 16 is I (filter 50Hz) [A], the engine speed is N [rpm], and the ignition mechanism 14 is Let the voltage of the power transistor (not shown) be EpTr [V]. As is clear from this Figure 7, the voltage is
No explosion occurs when EpTr is applied, and explosion occurs from the time when the second voltage EpTr is applied. Also, the engine speed N fluctuates greatly.
If the speed is 900rpm or more, startup is complete.

[Effect of idea]

As is clear from the above detailed explanation, according to this invention, in a four-stroke gas engine, a predetermined stroke is detected based on the engine speed state after a predetermined period of time has elapsed from the start of the starter, and the crankshaft rotates two revolutions. By providing a control unit that operates the ignition system so as to ignite the engine once, and also operates the fuel supply system almost simultaneously with the operation of the ignition system to supply gas fuel to the gas engine, the occurrence of abandoned fire is prevented. At the same time, gas fuel is not supplied unnecessarily, gas explosions and the like can be avoided, damage to the gas engine and its peripheral parts can be prevented, and safety can be improved.

[Brief explanation of drawings]

Figures 1 to 7 show an embodiment of this invention, Figure 1 is a schematic diagram of the fuel supply system, and Figure 2 is a schematic diagram of the transition of the protrusion of the flywheel to the notch at the position of the pulse generating coil. Explanatory drawing, Fig. 3 is a schematic explanatory drawing when the notch of the flywheel transitions to the protruding part at the position of the pulse generating coil, Fig. 4
The figure is a voltage waveform diagram generated by the pulse generating coil, Figure 5 is a flowchart explaining the operation of this embodiment, Figure 6 is a timing chart at the time of starting, and Figure 7
The figure is a waveform diagram of voltage and current at each part of the engine starting. In the figure, 2 is a gas engine, 4 is a carburetor,
6 is a throttle valve, 14 is an ignition mechanism, 16 is a starter,
24 is a fuel supply valve, 30 is a control section, and 34 is an ignition signal detection mechanism.

Claims (1)

[Scope of utility model registration request] In a gas engine fuel supply system that supplies gas fuel to a 4-cycle gas engine, a predetermined stroke is detected based on the engine speed state after a predetermined time has elapsed from the start of the starter, and the ignition is performed two revolutions of the crankshaft. A fuel supply device for a gas engine, comprising a control unit that operates an ignition system for one time and operates a fuel supply system substantially simultaneously with the operation of the ignition system to supply gas fuel to the gas engine. .