JPS6357848A - Starter device for gas engine - Google Patents

Abstract

PURPOSE:To prevent the generation of after-fire or the like, by stopping a fuel supply system and an ignition system while starting a start system and replacing residual gas with new air thereafter restarting an engine, in case of the concentration of gas reaching a predetermined value lower than the limit concentration of combustion when the gas engine is started. CONSTITUTION:If a starting switch is operated when an LPG internal combustion engine 2 is started, a control part 30 supplies fuel to the internal combustion engine 2 through an introducing passage 18 and a mixer 4 by turning on a fuel solenoid valve 22 while performs cranking by turning on a starter 10. While an ignition mechanism 12 is turned on performing ignition and driving the engine 2. Here the control part, when the engine is placed in an operative condition that the concentration of combustible gas in an exhaust passage 34 by a gas concentration detector 36 is decided to reach predetermined concentration lower than the limit concentration of combustion, turns off the fuel solenoid valve 22 while turns on an air solenoid valve 28. In this way, air is introduced to the engine 2, and after the combustible gas of high concentration is replaced with the new air, the starter 10 is driven restarting the engine.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a gas engine starting device, and in particular, when the combustible gas concentration in the exhaust system reaches a predetermined concentration lower than the flammability limit concentration when starting an internal combustion engine. The combustible gas remaining in the exhaust system is automatically discharged, thereby preventing the occurrence of afterfire or gas explosion. .

[Conventional technology]

In addition to gasoline and light oil for diesel engines, internal combustion engines include LPG internal combustion engines that use liquefied gas, such as LPG, as fuel. LPG has various advantages such as low fuel cost, good mixing with air, complete combustion, and little air pollution due to exhaust gas. As for the LPG internal combustion engine, for example, Japanese Utility Model Publication No. 61-6265 and Japanese Unexamined Patent Publication No. 56
It is disclosed in the publication No.-146044. Jitsuko 1986-
The device described in Publication No. 6265 activates an alarm device and stops operation of the internal combustion engine when the concentration of flammable gas flowing into the crank chamber reaches a predetermined concentration lower than the flammability limit concentration, thereby preventing a gas explosion. It is prevented. In addition, the device described in Japanese Patent Application Laid-Open No. 146044/1983 drives the valve opening device only for a predetermined time set in a timer device from the moment the starting switch is closed when starting the internal combustion engine, and is extremely short from the time of starting. A rich air-fuel mixture is supplied to the internal combustion engine for a limited period of time to improve starting performance.

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 fuel electromagnetic valve is turned ON for, for example, 10 seconds, and then the starter is turned ON and cranks the internal combustion engine. The ignition mechanism is ONL and ignites. This state is maintained for a certain period of time, and if the internal combustion engine does not start completely within this period, the ignition mechanism is turned OFF and the scooter is turned off.
Switch to FF and stop starting. The internal combustion engine is restarted after a predetermined pause time, for example, 5 seconds has elapsed.

[Problem that the invention seeks to solve]

However, when starting the internal combustion engine, if the engine does not start completely due to a defect in the ignition mechanism, for example, the above-mentioned startup is repeated, and during this time unburned combustible gas flows into the exhaust passage of the exhaust system. etc. will remain. For this reason, when the concentration of flammable gas in the exhaust passage gradually increases and reaches the flammability limit concentration, ignition by the ignition mechanism at restart causes gas explosions in the afterfire and around the internal combustion engine. The surrounding parts were damaged and dangerous.

[Purpose of the invention]

Therefore, an object of the present invention is to eliminate the above-mentioned inconvenience, and to solve the problem when the internal combustion engine does not start completely and the concentration of combustible gas remaining in the exhaust system reaches a predetermined concentration lower than the flammability limit concentration. replaces the remaining flammable gas with fresh air and automatically exhausts it, thereby restarting the engine when the flammable gas is below a predetermined concentration that is lower than the flammability limit concentration,
An object of the present invention is to realize a starting device for a gas engine that can avoid the occurrence of afterfires, gas explosions, etc. around the internal combustion engine, prevent damage to the internal combustion engine and its peripheral parts, and improve safety.

[Means for solving problems]

In order to achieve this object, the present invention provides a gas concentration detection means for detecting the combustible gas concentration state of the exhaust system and outputting a signal, and when the internal combustion engine is started, the gas concentration detected by the gas concentration detection means is When the concentration reaches a predetermined concentration lower than the flammability limit concentration, the operation of the fuel supply system and ignition system is stopped, and after the starting system is activated and the remaining flammable gas is replaced with fresh air, the internal combustion engine is restarted. The present invention is characterized in that it includes a control means for controlling the engine to start.

[Effect]

According to the configuration of the present invention, when the flammable gas concentration in the exhaust system reaches a predetermined concentration lower than the flammability limit concentration when starting the internal combustion engine, the control means stops the operation of the fuel supply system and the ignition system. On the other hand, the internal combustion engine is controlled to be restarted after the combustible gas remaining in the exhaust system is replaced with fresh air by driving the starting system and performing cranking without supplying fuel or igniting. In this way, when the internal combustion engine does not start completely, the high concentration of flammable gas remaining in the exhaust system can be replaced with fresh air, and the combustible gas concentration in the exhaust system is lower than the flammability limit concentration. Since the restart is performed in a state where the concentration is less than that, the occurrence of afterfire in the exhaust system and gas explosion around the internal combustion engine is avoided, and damage to the internal combustion engine and its peripheral parts is prevented, thereby improving safety.

〔Example〕

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

1 to 3 show embodiments of this invention. In the figure, 2 is the 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, 1
0 is a starter, 12 is an ignition mechanism, and 14 is a fuel tank. One end side of a fuel supply passage 16 is connected to the fuel tank 14, and the other end side of this fuel supply passage 16 is connected to a fuel air introduction passage 18 communicating with the mixer 4 at a confluence point A. In the fuel supply passage 16, a primary regulator 20 and a fuel solenoid valve 2 are installed in order from the side closest to the fuel tank 14.
2, and a secondary regulator 24 is provided. Further, an air supply passage 26 is connected to the fuel air introduction passage 18 at the merging point A. This air supply passage 26 is provided with an air intake solenoid valve 28 .

The throttle valve 8 is opened and closed by a stepping motor 32 operated by a command signal from a control section 30 constituting a control means.

The control section 30 is connected to a gas concentration detector 36, which is gas concentration detection means for detecting the combustible gas concentration state in, for example, the exhaust passage 34 of the exhaust system and outputting a signal. Further, when the control unit 30 receives a signal indicating that the gas concentration detected by the gas concentration detector 36 has reached a predetermined concentration lower than the flammability limit concentration when starting the internal combustion engine 2, the control unit 30 stops the fuel supply. In order to stop the fuel, the fuel electromagnetic valve 22 is turned off, and the ignition mechanism 12 is turned off so as not to ignite the fuel in the ignition system.
OFF, while the combustion chamber of the internal combustion engine 2 (not shown)
In order to introduce fresh air into the engine, the air intake solenoid valve 28 is turned on, and the starter 10 of the starting system is turned on. That is, when the internal combustion engine 2 is started, if the combustible gas concentration in the exhaust passage 34 reaches a predetermined concentration lower than the flammability limit concentration,
The configuration is such that the combustible gas is replaced with fresh air, and the internal combustion engine 2 is restarted when the combustible gas is below the above-mentioned predetermined concentration, thereby preventing afterfire, gas explosions around the internal combustion engine 2, etc.

The operation of this embodiment will be explained below based on the flowchart of FIG. 2 and the timing chart of FIG. 3.

In step 102 of FIG. 2, it is determined whether the start signal is on. i.e. starting switch (not shown)
If the operation is not performed and step 102 is No,
Continue to judge whether the start signal is ON or not. On the other hand, if the start switch is operated, the start signal is turned ON, and step 102 is YES ((81) in FIG.
position), turn on the fuel solenoid valve 22 (step 10
4) supplying fuel to the internal combustion engine 2 via the fuel air introduction passage 18 by stopping and communicating the fuel supply passage 16;
The starter 10 is turned on (step 106) to perform cranking, and the ignition mechanism 12 is turned on (step 106).
08) Then, ignite and open the mixer 4 (
Step 110).

Next, a timer is started to maintain this state for a predetermined period of 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 flammability limit concentration (step 114). In this step 114, if the combustible gas is NO and has reached a predetermined concentration lower than the flammability limit concentration (as shown by position b1 in FIG. 3), the fuel supply from the fuel supply passage 16 is stopped. The fuel solenoid valve 22 is set to 0FF to stop the engine (step 116), and the air intake solenoid valve 28 is turned on to introduce fresh air into the combustion chamber of the internal combustion engine 2 via the fuel air introduction passage 18 (step 11).
8). Furthermore, the ignition mechanism 12 is turned off (step 120) so that ignition is not performed. In this state, fresh air is introduced into the combustion chamber of the internal combustion engine 2, so
The highly concentrated combustible gas is replaced with fresh air, and the combustible gas in the combustion chamber and the exhaust passage 34 is actively discharged to the outside.

Then, in step 122, the exhaust passage 34
It is determined whether the combustible gas concentration has reached a predetermined concentration lower than the flammability limit concentration. If the combustible gas concentration has reached a predetermined concentration lower than the flammability limit concentration, that is, if step 122 is NO, this judgment state is continued. On the other hand, if the combustible gas concentration has not reached the predetermined concentration lower than the flammability limit concentration, that is, in step 12
If 2 is YES (shown at position 01 in Figure 3),
The starter 10 is turned off (step 124), and the air intake solenoid valve 28 is turned off (step 12).
6), and the mixer 4 is closed (step 128). And since the internal combustion engine 2 will not restart immediately,
In order to maintain this state for a predetermined time T, for example 5 seconds, a timer is started (step 130).

Then, in step 132, it is determined whether 5 seconds have elapsed. That is, step 132 is N in less than 5 seconds.

In this case, this state is maintained as it is. Also, 5
If the answer in step 132 is YES after seconds have elapsed, the process jumps to step 102 and restarts the engine (as shown by position ld in FIG. 3).

On the other hand, in step 114, if the combustible gas concentration has not reached the predetermined concentration lower than the flammable limit concentration, YES.
In this case, the engine speed is 80 Orr in step 13.1.
Determine whether or not it is equal to or greater than pm. Engine speed is 800 rp
m or more and if step 134 is YES, it is assumed that the start-up of the internal PI engine 2 has been completed. Further, if the engine speed is less than 80 rpm and step 134 is NO,
In step 136, it is determined whether 10 seconds have elapsed. 1
If it is less than 0 seconds and the answer in step 136 is NO, the process returns to step 114 and the combustible gas concentration state is determined.

If 10 seconds have passed and step 136 is YES, the fuel solenoid valve 22 is turned OFF (step 138), the starter 10 is turned OFF (step 140),
The ignition mechanism 12 is turned off (step 142), and the mixer 4 is placed in the closed state B (step 144). Next, since the internal combustion engine 2 does not restart immediately, the timer is started for 5 seconds in step 130, and if 5 seconds have elapsed and step 132 is YES, the process jumps to step 102 and the restart is performed. (see Figure 3)
d) indicated by position).

As a result, the internal combustion engine 2 can always be started when the combustible gas concentration in the exhaust passage 34 is less than a predetermined concentration lower than the flammability limit concentration. The present invention aims to improve safety by avoiding damage to the internal combustion engine 2 and its peripheral parts.

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

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 is the state in which the flammable gas concentration in the exhaust passage 34 is less than the above-mentioned predetermined concentration. However, it is also possible to use a timer mechanism to set the starter 10 for a predetermined period of time from when the internal combustion engine 2 does not start for the first time until the combustible gas concentration falls below the predetermined concentration mentioned above. It is.

〔Effect of the invention〕

As is clear from the above detailed description, according to the present invention,
When the combustible gas concentration in the exhaust system reaches a predetermined concentration lower than the flammability limit concentration when starting an internal combustion engine, cranking is performed without fuel supply or ignition to eliminate the high concentration of combustible gas remaining in the exhaust system. The combustible gas can be replaced with fresh air and automatically discharged, and the restart can be performed after the flammable gas has fallen below a predetermined concentration, which is lower than the flammability limit concentration.
The occurrence of afterfires, gas explosions, etc. around the internal combustion engine can be avoided, and damage to the internal combustion engine and its surrounding parts can be prevented, thereby improving safety.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, in which FIG. 1 is a schematic diagram of a starting device, FIG. 2 is a flowchart 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
26 is a fuel solenoid valve, 26 is an air supply passage, 28 is an air suction solenoid valve, 30 is a control unit, 34 is an exhaust passage, and 36 is a solenoid valve for fuel.
is a gas) 2 degree detector. Patent Applicant Suzuki Motor Co., Ltd. Agent Patent Attorney Yoshimi Saigo Figure 1 Figure 3 2-36'ε Ne City Author (Spontaneous) July 3, 1985 Commissioner of the Japan Patent Office Kuro 1) Akio Yu Tono Patent Application No. 61-201851 2 Name of the invention Gas engine starting device 3 Relationship with the person making the amendment 1 Patent applicant address 300 Takatsuka, Kamimura, Hamana-gun, Shizuoka Prefecture Name Name
(208) Suzuki Motor Co., Ltd. Representative Suzuki
4, Agent Address: 101 03-292-4
411 (Representative) Address Saigo Patent Building, 2-8 Kanda Ogawamachi, Chiyoda-ku, Tokyo Name (8005) Patent Attorney 41 Ta 1! μ Yoshimi 5, Date of amendment order Voluntary 6, Subject of amendment (1), Detailed explanation of the invention in the specification column (2), Brief explanation of drawings in the specification column 7, Contents of amendment fil, Specification Page 6, line 17 of the book “Air supply 1m path 2
6" is corrected to "air supply passage 26 for introducing fresh air." (2), page 6, lines 18-19 of the specification, ``This air supply passage 26 is provided with an air suction solenoid valve 28.'' is deleted. (3), page 7, lines 12-14 of the specification, “Internal combustion engine 2
Turn on...and delete ". (4) The phrase "Together, we will bring new energy to..." on page 9, lines 9 to 12 of the specification will be deleted. (5), page 9, lines 14-15 of the specification, “Internal combustion engine 2
``Because...'' is corrected to ``Because fresh air is introduced into the combustion chamber of the internal combustion engine 2 from the air supply passage 26.'' ``Solenoid valve for use'' is deleted. (8) Figures 1, 2, and 3 are corrected as shown in the attached drawings. Figure 1

Claims (1)

[Claims] A gas concentration detection means is provided for detecting a combustible gas concentration state in the exhaust system and outputting a signal, and when the gas concentration detected by the gas concentration detection means reaches a predetermined concentration lower than a flammability limit concentration when the internal combustion engine is started. In this case, a control means is provided to stop the operation of the fuel supply system and the ignition system, while driving the starting system to restart the internal combustion engine after replacing the remaining flammable gas with fresh air. A gas engine starting device characterized by: