JPH07116993B2 - Gas engine starter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas engine starter, and more particularly, when the combustible gas concentration of an exhaust system reaches a predetermined concentration lower than a combustion limit concentration when starting an internal combustion engine. Relates to a gas engine starter capable of automatically discharging the flammable gas remaining in the exhaust system, thereby restarting the internal combustion engine without causing afterfire or gas explosion, and improving safety.

[Conventional technology]

Examples of internal combustion engines include LPG internal combustion engines that use liquefied gas such as LPG as fuel, in addition to gasoline and light oil for diesel engines. LPG has various advantages such as low fuel cost, good mixing with air, complete combustion, and low air pollution due to exhaust gas. The LPG internal combustion engine is disclosed, for example, in Japanese Utility Model Publication No. 61-6265 and Japanese Patent Application Publication No. 56-146044. The one described in Japanese Utility Model Publication No. 61-6265 is
When the concentration of the combustible gas flowing into the crank chamber reaches a predetermined concentration lower than the combustion limit concentration, the alarm device is activated and the operation of the internal combustion engine is stopped to prevent the gas explosion. Further, the one described in Japanese Patent Laid-Open No. 56-146044 drives the valve opening device only for a predetermined time set in the timer device from the moment when the start switch is closed at the time of starting the internal combustion engine, and is extremely short from the start. The startability is improved by supplying a rich air-fuel mixture to the internal combustion engine only during the period.

By the way, when starting a normal LPG internal combustion engine, when the start switch is turned on and the start signal is turned on, the solenoid valve for fuel is turned on for 10 seconds, and the starter is turned on.
Cranks the internal combustion engine and turns on the ignition mechanism.
And ignite. This state is maintained for a certain time, and if the internal combustion engine does not start completely within this time, the ignition mechanism is
Turn off the starter and stop the start. The internal combustion engine is restarted after a lapse of a predetermined rest time, for example, 5 seconds.

[Problems to be solved by the invention]

However, at the time of starting the internal combustion engine, if the internal combustion engine is not completely started due to a failure of the ignition mechanism or the like, the above-mentioned starting is repeated, and during this time, the unburned combustible gas is exhausted through the exhaust passage of the exhaust system. Etc. will remain. Therefore, when the concentration of the combustible gas in the exhaust passage gradually increases and reaches the combustion limit concentration, ignition by the restart ignition mechanism causes a gas explosion around the afterfire or the internal combustion engine, resulting in internal combustion The surrounding parts were damaged and dangerous.

[Object of the Invention]

Therefore, an object of the present invention is to eliminate the above-mentioned inconvenience, and when the internal combustion engine does not start completely at the time of starting the internal combustion engine and the combustible gas concentration remaining in the exhaust system reaches a predetermined concentration lower than the combustion limit concentration. Replaces the remaining flammable gas with fresh air and automatically discharges it, thereby restarting when the flammable gas is below a predetermined concentration lower than the combustion limit concentration,
An object of the present invention is to realize a gas engine starter capable of avoiding the occurrence of a gas explosion or the like around an afterfire or an internal combustion engine, preventing damage to the internal combustion engine and its peripheral parts, and improving safety.

[Means for solving problems]

In order to achieve this object, the present invention is provided with gas concentration detecting means for detecting a combustible gas concentration state of the exhaust system and outputting a signal, and the gas concentration detected by the gas concentration detecting means at the time of starting the internal combustion engine is When a predetermined concentration lower than the combustion limit concentration is reached, the operation of the fuel supply system and the ignition system is stopped, while the start system is driven to replace the remaining combustible gas with fresh air, and then the internal combustion engine is restarted. It is characterized in that a control means for controlling to start the engine is provided.

[Action]

According to the configuration of the present invention, the control means stops the operation of the fuel supply system and the ignition system when the combustible gas concentration of the exhaust system reaches a predetermined concentration lower than the combustion limit concentration at the time of starting the internal combustion engine. On the other hand, the starting system is driven to perform cranking without fuel supply and ignition, so that the internal combustion engine is restarted after the combustible gas remaining in the exhaust system is replaced with fresh air. Thus, when the internal combustion engine does not start completely, the high concentration of combustible gas remaining in the exhaust system can be replaced with fresh air, and the concentration of combustible gas in the exhaust system is lower than the combustion limit concentration. Since the restart is performed in a state of less than the concentration, occurrence of an afterfire in the exhaust system and gas explosion around the internal combustion engine is avoided, damage to the internal combustion engine and its peripheral parts is prevented, and safety is improved.

〔Example〕

Embodiments of the present invention will be described in detail and specifically below with reference to the drawings.

1 to 3 show an embodiment of the present invention. In the figure, 2 is an LPG internal combustion engine (hereinafter simply referred to as "internal combustion engine"), 4 is a mixer, 6 is an intake passage, 8 is a throttle valve, 10 is a starter, 12 is an ignition mechanism, and 14 is a fuel tank. One end of a fuel supply passage 16 is connected to the fuel tank 14, and the other end of the fuel supply passage 16 is connected to a fuel air introduction passage 18 communicating with the mixer 4 at a junction A. In the fuel supply passage 16, a primary regulator 20, a fuel solenoid valve 22, and a secondary regulator are sequentially installed from the side closer to the fuel tank 14.
24 are provided. Further, in the fuel air introduction passage 18,
At the confluence A, an air supply passage 26 for introducing fresh air is connected.

The throttle valve 8 is opened and closed by a stepping motor 32 that operates according to a command signal from a control unit 30 that constitutes a control means.

The control unit 30 is connected to a gas concentration detector 36, which is a gas concentration detection unit that detects a combustible gas concentration state in the exhaust passage 34 of the exhaust system and outputs a signal. Further, when the internal combustion engine 2 is started, the control unit 30 supplies fuel when a signal indicating that the gas concentration detected by the gas concentration detector 36 has reached a predetermined concentration lower than the combustion limit concentration is supplied. The solenoid valve 22 for fuel is turned off to stop, and the ignition mechanism 12 is turned off so that ignition is not performed in the ignition system, while the starter 10 of the starting system is turned on. That is,
At the time of starting the internal combustion engine 2, when the concentration of the combustible gas in the exhaust passage 34 reaches a predetermined concentration lower than the combustion limit concentration,
The combustible gas is replaced with fresh air, the internal combustion engine 2 is restarted when the combustible gas is less than the above-mentioned predetermined concentration, and the afterfire and gas explosion around the internal combustion engine 2 are prevented.

The operation of this embodiment will be described below with reference to the flowchart of FIG. 2 and the timing chart of FIG.

In step 102 of FIG. 2, it is determined whether the start signal is on. That is, if the start switch (not shown) is not operated and step 102 is NO, the determination as to whether or not the start signal is ON is continued. On the other hand, when the start switch is operated and the start signal is turned on, the step
If 102 is YES (shown at the position (a) in FIG. 3), the fuel solenoid valve 22 is turned on (step 104) and the fuel supply passage 1 is turned on.
By connecting 6 to each other, fuel is supplied to the internal combustion engine 2 through the fuel-air introducing passage 18, and the starter 10 is turned on (step 10
6) Cranking is performed and the ignition mechanism 12 is turned on.
The ignition is performed with N (step 108), and the mixer 4 is opened (step 110). Next, a timer is started so that this state is maintained for a predetermined time, for example, 10 seconds (step 112).

Next, it is determined whether the combustible gas concentration in the exhaust passage 34 has reached a predetermined concentration lower than the combustion limit concentration (step
114). In this step 114, if the combustible gas has a high concentration and has reached a predetermined concentration lower than the combustion limit concentration (NO at the position (b) in FIG. 3), the fuel supply passage 16
The fuel solenoid valve 22 is turned off (step 116) in order to stop the fuel supply from. Furthermore, to prevent ignition,
The ignition mechanism 12 is turned off (step 120). In this state, fresh air is introduced into the combustion chamber of the internal combustion engine 2 from the air supply passage 26, so that the high-concentration combustible gas is replaced with fresh air, and the combustible gas in the combustion chamber and the exhaust passage 34 is positively activated. To be discharged externally.

Then, in step 122, it is again determined whether or not the concentration of the combustible gas in the exhaust passage 34 has reached a predetermined concentration lower than the combustion limit concentration. If the combustible gas concentration has reached the prescribed concentration above the combustion limit concentration, that is, step 12
When 2 is NO, this judgment state is continued. on the other hand,
When the combustible gas concentration has not reached the predetermined concentration lower than the combustion limit concentration, that is, when step 122 is YES (shown at the position in FIG. 3 (c)), the starter 10 is turned off (step 124). And the mixer 4 is closed (step 12
8) Since the internal combustion engine 2 does not restart immediately, a timer start (step 130) is performed in order to maintain this state for a predetermined time T, for example, 5 seconds. Then, in step 132, it is determined whether or not 5 seconds have elapsed. That is, if step 132 is NO for less than 5 seconds, this state is maintained as it is. If 5 seconds have elapsed and step 132 is YES, the process jumps to step 102 and restarts (shown at position (d) in FIG. 3).

On the other hand, if YES in step 114 where the combustible gas concentration has not reached the predetermined concentration lower than the combustion limit concentration, it is determined in step 134 whether the engine speed is 800 rpm or more. Step 134 is Y when the engine speed is 800 rpm or more
In the case of ES, it is assumed that the start of the internal combustion engine 2 has been completed. If the engine speed is less than 800 rpm, step 134 is NO.
In the case of, it is determined in step 136 whether 10 seconds have elapsed. If step 136 is NO in less than 10 seconds, the process returns to step 114 to determine the combustible gas concentration state. Also, 1
If 0 seconds have passed and step 136 is YES, the solenoid valve 22 for fuel is turned off (step 138), the starter 10 is turned off (step 140), the ignition mechanism 12 is turned off (step 142), and mixing is performed. The container 4 is closed (step 144).
Next, since the internal combustion engine 2 does not restart immediately, a timer start for 5 seconds is performed in step 130, and
If 5 seconds have elapsed and step 132 is YES, step 10
Jump to 2 and restart ((d) in Fig. 3)
Position).

As a result, the internal combustion engine 2 is always operated in a state where the combustible gas concentration in the exhaust passage 34 is lower than a predetermined concentration lower than the combustion limit concentration.
Therefore, it is possible to avoid the occurrence of a gas explosion around the afterfire and the internal combustion engine 2, prevent damage to the internal combustion engine 2 and its peripheral parts, and improve safety.

Further, since the combustible gas concentration of the exhaust system can be detected by the gas concentration detector 36, the combustible gas concentration can be accurately detected.

In addition, according to this embodiment, the state in which the operation of the fuel supply system and the ignition system is stopped and the starter 10 of the starting system is driven,
It was carried out until the state where the combustible gas concentration in the exhaust passage 34 became less than the above-mentioned predetermined concentration was detected, but the combustible gas concentration was above the starter 10 when the internal combustion engine 2 was not started for the first time. It is also possible to set it by a timer mechanism for a predetermined time period in which the density is lower than the predetermined density.

〔The invention's effect〕

As is apparent from the above detailed description, according to the present invention,
When the concentration of combustible gas in the exhaust system reaches a predetermined concentration lower than the combustion limit concentration when the internal combustion engine is started, fuel is not supplied and ignition is performed, and cranking is performed to maintain a high concentration of combustible gas remaining in the exhaust system. Gas can be replaced with fresh air and automatically discharged, and restarted after the combustible gas falls below a specified concentration lower than the combustion limit concentration. It is possible to prevent the occurrence of gas explosion and the like, prevent damage to the internal combustion engine and its peripheral parts, and improve safety.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is a schematic diagram of a starting device, FIG. 2 is a flow chart for explaining the operation of this embodiment, and FIG. 3 is a timing chart. In the figure, 2 is an internal combustion engine, 4 is a mixer, 6 is an intake passage, 10 is a starter, 12 is an ignition mechanism, 14 is a fuel tank, 16
Is a fuel supply passage, 18 is a fuel air introduction passage, 22 is a fuel solenoid valve, 26 is an air supply passage, 30 is a control unit, 34 is an exhaust passage,
36 is a gas concentration detector.

Claims (1)

[Claims] 1. A gas concentration detecting means for detecting a combustible gas concentration state of an exhaust system and outputting a signal, wherein the gas concentration detected by the gas concentration detecting means at the time of starting an internal combustion engine is lower than a combustion limit concentration. When a predetermined concentration is reached, the fuel supply system and the ignition system are stopped, while the start system is driven to replace the remaining combustible gas with fresh air, and then the internal combustion engine is restarted. A starting device for a gas engine, comprising: