JPH06213077A - Gas engine mixer control method and mixer control device - Google Patents

Abstract

(57) [Summary] [Purpose] During gas purging when the engine is stopped, the intake / exhaust amount Q is momentarily increased to prevent the coagulated water from scattering from the tail pipe of the exhaust muffler 16, and the self-rotation of the engine is shortened. Stop in time. Constitution: When the fuel supply signal K is turned off, the supply of fuel gas to the mixer 1 is stopped, and at the same time, the throttle valve 2 is fully closed and the ignition plug 5 is turned off. As a result, the engine does not rotate by itself and rapidly drops to a predetermined stop rotation speed n _L, but after that, the starter motor 17 is started to purge the gas in the mixer 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas engine used in a cogeneration system, an engine generator, etc., and particularly, when the engine is stopped, it removes unburned gas remaining in a manifold or a cylinder (hereinafter referred to as a gas purge). The present invention relates to a mixer control method for a gas engine and a mixer control device used in the above.

[0002]

2. Description of the Related Art The above-mentioned gas purging has conventionally been performed by the procedure shown in FIG. Here, FIG. 1A is a flow chart showing a mixer control method for a gas engine,
(B) is a time chart showing the relationship between the opening / closing of the fuel supply valve, the opening V of the throttle valve, the engine speed N, and the intake / exhaust amount Q of the engine corresponding to the flowchart.

As shown in FIG. 3A, it is determined in step S ₁ that the fuel supply signal K is turned off, and in step S ₂ it is determined that the fuel supply signal K is turned off.
The fuel supply valve is closed to stop the supply of fuel gas. Step S ₃ in the rotational speed N of the engine is indirectly detects the completion of purge in a mixer by decreases to a predetermined stop rotational speed n _L, based on the detection in step S _4, the throttle valve by the governor actuator The opening V is fully closed and the spark plug is turned off. As a result, the engine is stopped in step S ₅ . That is, the unburned gas in the manifold or the combustion chamber is burned in the combustion chamber and gas purge is performed between the closing of the fuel gas supply passage in step S ₂ and the turning off of the spark plug in step S ₄ .

[0004]

The above-mentioned prior art has the following problems. The throttle valve of the gas engine is operated by a governor actuator, and the opening degree V of the throttle valve is reduced when the load of the engine decreases and the rotation speed increases, and when the load increases and the rotation speed decreases. Is controlled in the opening direction, and the engine speed N is maintained at the rated speed (for example, 1800 rpm).

When the engine is stopped, as shown in FIG. 3 (B), the rated speed N decreases from the moment the gas supply passage is closed, and the throttle valve is fully opened. Therefore, the intake / exhaust amount Q momentarily increases, and coagulated water (water vapor in the exhaust gas coagulates and adheres to the inside of the exhaust muffler) is blown out from the tail pipe of the exhaust muffler, and this coagulated water is scattered. And stain the area around the engine. Especially when the engine is stopped during low load operation, the coagulated water is blown out severely.

Further, since unburned gas remaining in the manifold and the combustion chamber is burned in the combustion chamber of the engine to perform gas purging, it takes some time before the self-rotation of the engine is stopped, and gas purging cannot be performed quickly. .
The present invention has been made in consideration of such circumstances, and has technical problems of preventing scattering of the coagulated water and quick gas purging.

[0007]

In order to solve the above-mentioned problems, the means adopted by the invention described in claim 1 supplies the fuel gas to the mixer 1 when the fuel supply signal K is turned off. In a mixer control method for a gas engine in which the fuel gas remaining in the mixer 1 is gas-purged after stopping, and then the engine is stopped, in the same time as the supply of the fuel gas is stopped, the ignition plug 5 is turned off and the throttle valve 2 Is fully closed, and after the engine speed N has dropped to a predetermined stop speed n _L , the starter motor 17 is started to purge the gas in the mixer 1.

In the means adopted by the invention described in claim 2, the throttle valve 2 of the mixer 1 is connected to the governor actuator 4, and the fuel gas supply passage 12 to the mixer 1 is provided with the fuel supply valve 13. A detector 7 for detecting the rotational speed N of the engine E is provided, and the opening V of the throttle valve 2 is adjustable via a control circuit 10. In the control circuit 10, the fuel supply signal K is turned off. Based on this, the fuel supply valve 13 of the gas supply path 12 is closed to stop the supply of the fuel gas, the fuel gas remaining in the mixer 1 is gas-purged, and then the engine E is stopped. In the mixer control device, the control circuit 10 turns off the spark plug 5 and fully closes the opening degree V of the throttle valve 2 at the same time when the supply of the fuel gas is stopped. Rotational speed N of the emission is characterized in that it has configured to an gas purge by starting the mixer 1 the starter motor 17 after lowered to a predetermined stop rotational speed n _L.

[0009]

The invention described in claim 1 and claim 2 operates as follows. It should be noted that the description will be given with reference to FIGS. 1 and 2 for easy understanding. Here, FIG. 1 is a schematic diagram of a mixer control device for a gas engine according to the present invention,
FIG. 2A is a flowchart relating to the mixer control method,
FIG. 3B is a time chart showing the relationship between the opening / closing of the fuel supply valve, the opening V of the throttle valve, the engine speed N, and the intake / exhaust amount Q of the engine corresponding to the flowchart.

In the present invention, based on the fact that the fuel supply signal K is turned off, the fuel supply valve 13 of the gas supply passage 12 is closed to stop the supply of fuel gas, and at the same time, the spark plug 5 is turned off. Together with the opening V of the throttle valve 2
Fully closed. As a result, the engine E does not rotate by itself, the rotation speed N rapidly decreases, and the intake / exhaust amount Q also rapidly decreases as the engine rotation speed N decreases. Then, after the engine speed N has dropped to a predetermined stop speed n _L , the starter motor 17 is started to purge the gas in the mixer 1.

[0011]

According to the present invention, unlike the conventional example, the intake / exhaust amount Q does not increase instantaneously at the moment when the supply of the fuel gas is stopped, the engine speed N rapidly decreases, and the intake / exhaust amount increases. The quantity Q also decreases rapidly with a decrease in the engine speed N, so that the problem of contaminating the peripheral part of the engine due to the scattering of the coagulated water is solved without blowing out the coagulated water from the tail pipe of the exhaust muffler. To do.

Further, unlike the conventional example in which unburned gas remaining in the manifold or the combustion chamber is burned in the combustion chamber of the engine to perform gas purging, the engine does not rotate by itself, and the engine speed N stops at a predetermined level. Since the number of revolutions rapidly decreases to n _L , in the present invention in which the cell motor 17 is rotated to purge the gas in the mixer 1, the gas can be rapidly purged.

[0013]

First, a gas engine will be described with reference to FIG. In the gas engine E that uses gas as fuel,
Gas supply path 12 that connects the fuel gas source 11 and the mixer 1
A fuel supply valve 13 and a differential pressure type flow rate controller 14 called a zero governor are provided in the middle of the operation, and the flow rate of the fuel gas is adjusted by the differential pressure between the intake negative pressure of the engine E and the atmospheric pressure, and the mixer 1
Is configured to supply.

As shown in FIG. 1, the mixer control apparatus of the present invention connects a governor actuator 4 to a throttle valve 2 of a mixer 1 via a valve operating lever 3 and an ignition circuit 6 to an ignition plug 5 of an engine E. Connect and engine E
A detector 7 for detecting the number of revolutions N is provided, the opening V of the throttle valve 2 can be adjusted via the control circuit 10, and the starter motor 17 is drive-controlled. In FIG. 1, reference numeral 8 is a gear case, 9 is a key switch for outputting a fuel supply signal K, 15 is an air cleaner,
Reference numeral 16 is an exhaust muffler, and 18 is a timer for operating the starter motor 17 for a predetermined time.

The ignition circuit 6 of the ignition plug 5 is composed of an ignition coil and a distributor, and a high voltage is generated by the ignition coil, and a spark is ignited by the spark to the ignition plug 5 of each cylinder by the distributor. . Further, the detector 7 for detecting the rotation speed N of the engine E is constituted by a gear case 8 provided with an electromagnetic rotation sensor.

The control circuit 10 closes the fuel supply valve 13 of the gas supply passage 12 to stop the supply of the fuel gas, based on the fact that the fuel supply signal K is turned off by turning off the key switch 9. At the same time as the supply of the fuel gas is stopped, the ignition plug 5 is turned off, the opening degree V of the throttle valve 2 is fully closed, and the starter motor 17 is kept constant after the engine speed N drops to a predetermined stop speed n _L. Time T
The mixer 1 is operated to perform gas purging in the mixer 1, and the starter motor 17 is stopped after the gas purging is completed. When the starter motor 17 is started, the start command for the engine E is cut so that the engine is not started.

In this embodiment, as shown in FIG.
When the fuel supply signal K is turned off in step S ₁ , the supply of fuel gas is stopped in step S ₂ , the spark plug 5 is turned off, and the opening degree V of the throttle valve 2 is fully closed. Then, as shown in FIG. 2 (B), the engine speed N rapidly decreases, and the intake / exhaust amount Q also rapidly decreases as the engine speed N decreases. In step S ₃ , it is detected by the detection signal J that the engine speed N has decreased to a predetermined stop speed n _L (for example, 200 rpm), and in step S ₄ , the timer 18 is turned on based on the detection signal J. The cell motor 17 is operated for a certain period of time to purge the gas in the mixer 1. Detecting a time-up T in step S _5, resets the timer 18 in step S _6, to stop the rotation of the engine by turning off the starter motor 17.

As a result, unlike the conventional example, the intake / exhaust amount Q does not increase instantaneously at the moment when the supply of the fuel gas is stopped, and the engine speed N rapidly decreases, and at the same time,
The intake / exhaust amount Q also rapidly decreases as the engine speed N decreases, so that the coagulation water is not blown out from the tail pipe of the exhaust muffler, and the periphery of the engine is polluted by the scattering of the coagulation water. Disappears.

Further, unlike the conventional example in which the unburned gas remaining in the manifold or the combustion chamber is burned in the combustion chamber of the engine and the gas is purged by the self-rotation of the engine, the rotation speed N of the engine is a predetermined stop rotation speed n _L. In the present invention in which the starter motor 17 is started and the gas in the mixer 1 is purged after the temperature has dropped to 0, the gas purge can be executed promptly as much as the engine E does not rotate by itself.

In the above embodiment, at step S ₄ in FIG. 2A, the opening degree V of the throttle valve 2 is fully opened at the same time when the starter motor 17 is started (phantom line V ₂ in FIG. 2B). It is also possible, and in such a case, the scavenging can be further promoted and the gas purging can be executed quickly. At this time, even if the starter motor 17 is started, since the rotation speed is low, the coagulated water is not blown out from the tail pipe of the exhaust muffler.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a mixer control device for a gas engine according to the present invention.

2A and 2B show a mixer control method according to the present invention. FIG. 2A is a flowchart thereof, and FIG. 2B is a diagram showing the fuel supply valve opening / closing and throttle valve opening V corresponding to the flowchart.
2 is a time chart showing the relationship between the engine speed N and the engine intake / exhaust amount Q.

FIG. 3 shows a conventional mixer control method, and FIGS. 3A and 3B correspond to FIGS. 2A and 2B, respectively.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mixer, 2 ... Throttle valve, 4 ... Governor actuator, 5 ... Spark plug, 6 ... Ignition circuit, 7 ... Rotation detector, 10 ... Control circuit, 12 ... Gas supply path, 13 ... Fuel supply valve, 17 ... Throttle Valve, E ... Gas engine, J ... Detection signal, K ... Fuel supply signal, V ... Throttle valve opening.

Claims (2)

[Claims] 1. The mixer (1) is stopped by stopping the supply of fuel gas to the mixer (1) when the fuel supply signal (K) is turned off.
In a mixer control method for a gas engine, in which fuel gas remaining inside is gas-purged and then the engine is stopped, at the same time as the supply of the fuel gas is stopped, the spark plug (5) is turned off and the throttle valve (2) is opened. Degree (V) is fully closed, and the engine speed (N) is the specified stop speed.
A mixer control method for a gas engine, comprising: starting the starter motor (17) to purge the gas in the mixer (1) after the temperature has dropped to (n _L ). 2. A governor actuator (4) is connected to a throttle valve (2) of a mixer (1), and a fuel supply valve (1) is connected to a fuel gas supply passage (12) to the mixer (1).
3) is provided and a detector for detecting the number of revolutions (N) of the engine (E)
(7) is provided, and the throttle valve is provided through the control circuit (10).
The opening degree (V) of (2) is adjustable, and the control circuit (10) controls the fuel supply valve (12) of the gas supply path (12) based on the fact that the fuel supply signal (K) is turned off. 13) is closed to stop the supply of fuel gas, the fuel gas remaining in the mixer (1) is gas-purged, and then the engine (E) is stopped. The circuit (10) turns off the ignition plug (5) and the throttle valve (2) opening (V) at the same time when the supply of the fuel gas is stopped, and the engine speed
A mixer control device for a gas engine, characterized in that the starter motor (17) is started to purge gas in the mixer (1) after (N) has dropped to a predetermined stop speed (n _L ). .