JPS62265457A - Control device for gas engine - Google Patents

Abstract

PURPOSE:To prevent fuel from being still fed even after a gas engine being stopped, by providing sensors or the like for detecting the operating conditions of the gas engine, so that a gas valve is closed when an abnormal signal is delivered from the sensors. CONSTITUTION:A control section 17 in an engine control device 16 receives a cooling temperature detection signal, an engine rotational speed signal and a lubrication oil level signal from sensors 9 through 11, respectively, through an input circuit 18, and then computes a throttle valve opening degree with which the rotational speed of the engine is maintained in a predetermined regulated range, in accordance with the above-mentioned input signals to control the opening and closing of a throttle valve 5 by means of an actuator 20 through a drive circuit 19. In this arrangement, when any one of the input signals becomes abnormal, the control section 17 closes a gas valve 4 through a drive circuit 21 to cut off gas fuel so that the engine is stopped. With this arrangement it is possible to prevent fuel from being still fed even after the engine 1 being stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a control device for a gas engine operated on gas fuel.

[Prior art]

A gas engine is one that is operated using gas fuel such as city gas or propane gas. When this gas engine is used as a drive source for a heat pump, for example, a heating and cooling system, the engine speed is controlled within a certain specified range, and operation is stopped when the engine speed goes outside of that specified range. ing. It is also necessary to stop the gas engine due to causes such as when the lubricating oil in the crankcase drops below a specified level, or when the engine coolant temperature rises too much.

To stop the engine in this way, if it is a gasoline engine, it is enough to simply shut off the ignition system, but in the case of a gas engine, even if the ignition system is shut off, pressurized gas fuel will continue to be supplied. Therefore, the fuel will be wasted.

[Purpose of the invention]

It is an object of the present invention to provide a system that eliminates the waste of continuously supplying fuel even after the gas engine has stopped, and that allows the engine to be stopped reliably. 111 Ti installation.

[Structure of the invention]

The present invention, which achieves the above-mentioned requirements, provides a gas engine that is operated with gas fuel supplied through a gas valve, which is provided with a sensor that detects operating conditions such as rotational speed, and which detects the operating conditions detected by this sensor. The gas valve is characterized in that the gas valve is closed in response to an abnormal signal.

〔Example〕

FIG. 1 shows a gas engine control device according to an embodiment of the present invention. 1 is a gas engine operated with gas fuel such as city gas or propane gas, 2 is an intake pipe, and 3 is an exhaust pipe. A gas valve 4 is provided in the intake pipe 2, and the gas engine 1
The system cuts off the gas fuel supply to the

This gas valve 4 is a solenoid valve that is biased closed, and is designed to remain open while energized, but close when the energization is interrupted. A throttle valve 5 is provided downstream of the gas valve 4 to adjust the amount of gas fuel supplied to the engine 1.

The gas engine 1 includes a cylinder 6 and a piston 7, and is configured such that a crankshaft 8 is rotated by the reciprocating motion of the piston 7. 13 is the starting motor, its binion 1
4 moves forward and backward and can be freely engaged with and disengaged from the gear 15 at the end of the crankshaft 8. At startup, the binion 14 engages the gear 15.
The crankshaft 8 is rotated by meshing with the crankshaft 8.

A cooling water temperature sensor 9 is provided in the cooling jacket 6a of the cylinder 6. Further, an engine speed sensor 10 is provided opposite the crank web 8a. A lubricating oil sensor 11 is provided at the bottom of the crankcase 12 to detect the level of lubricating oil.

Reference numeral 16 denotes an engine control device that controls the operation of the gas engine. Control section 17 of this engine control device 16
A coolant temperature signal is input from the coolant temperature sensor 9, an engine rotation speed signal is input from the engine rotation speed sensor 10, and a lubricant oil level signal is input from the lubricant oil sensor 11 through the input circuit 18. It looks like this.

The control unit 17 calculates the opening degree of the throttle valve to maintain the engine speed within a certain specified range based on the above-mentioned input signals, and controls the opening degree of the throttle valve 5 by driving the actuator 20 via the drive circuit 19. The engine speed is always kept within a predetermined range by changing the engine speed.

Further, as shown in the flow chart shown in FIG. 3, the control unit 17 closes the gas valve 4 via the drive circuit 21 when any of the input signals is an abnormal signal outside the specified range,
It is designed to shut off the gas fuel and stop the gas engine. In this embodiment, this operational abnormality is defined as when the engine speed is out of the upper or lower limit of a predetermined range, when the engine coolant temperature is higher than the specified temperature, or when the lubricating oil level is lower than the specified range. This applies when the level drops below that level.

FIG. 2 shows an example of a control circuit that closes the gas valve 4 as shown in the flow chart of FIG. 3 when the above-mentioned operational abnormality signal is received.

In FIG. 2, the pulse signal of the engine speed sensor 10 is inputted via a frequency/voltage conversion circuit 22 to three differential amplifier circuits 23, 24, and 25, respectively. Among these, the differential amplifier circuit 23 displays no engine starting, and when the engine rotational speed signal is inputted on the positive side and exceeds a predetermined voltage corresponding to the starting rotational speed set on the negative side, outputs P, is generated and the AND circuit 27
It is designed to be input on one side.

On the other hand, the differential speed increasing circuits 24 and 25 set upper and lower limits of the engine speed within a predetermined range to be controlled. The differential amplifier circuit 24 that sets the upper limit side receives an engine rotation speed signal on the positive side, and when it exceeds the set voltage corresponding to the upper limit rotation speed set on the negative side, that is, when there is an overrun, the output P is output. It's starting to happen. In addition, an engine rotation speed signal is input on the negative side to the differential amplifier circuit 25 that sets the lower limit side, and when the set voltage corresponding to the upper limit rotation speed set on the plus side is exceeded, that is, the engine rotation speed is too low. It is designed to generate an output PL when

The abnormal signal outputs Pu and PL generated in this way are input to the OR circuit 26.

Further, the abnormal signal output Pe detected by the cooling water temperature sensor 9 and the lubricating oil sensor 11 is input to the OR circuit 26. These cooling water temperature sensor 9 and lubricating oil sensor 11 are normally closed sensors, and open when the cooling water temperature rises above a specified temperature and/or when the lubricating oil level falls below a specified level, thereby causing
The output Pe is input to the R circuit 26.

Therefore, the output Pu + of the abnormal signal as described above
When at least one of PL and Pe is input to the OR circuit 26, the OR circuit 26 generates an output P2.

On the other hand, there is an N between the OR circuit 26 and the AND circuit 27.
An OT circuit 28 is connected, and the output of the OR circuit 2G is inverted and input to the AND circuit 27.

That is, the NOT circuit 28 always generates an output under normal operating conditions, but when the output P2 is generated from the OR circuit 26 due to the abnormal signal as described above, the NOT circuit 28 does not require any human power to operate the AND circuit 27. It has become.

On the other hand, as described above, the output P is always input to the other input terminal of the AND circuit 27 when the engine 1 is at or above the starting rotation speed. Therefore, OR
When the output P2 at the time of abnormal operation is not generated from the circuit 26, the output from the NOT circuit 28 is inputted to the AND circuit 27, and thereby the output P3 is generated from the AND circuit 27, which closes the gas valve 4. The valve will be kept open.

On the other hand, when the output P2 is output from the OR circuit 26 due to the occurrence of an operational abnormality, the output from the NOT circuit 28 disappears, so the output P3 from the AND circuit 27 becomes null (no, and the gas valve 4 energized to close closes). It turns out.

Furthermore, when the engine 1 is started, but cannot be started, the output P is not generated from the differential amplifier circuit 23, so the output P3 is not generated from the AND circuit 27, and the gas valve 4 is energized to close. will be closed.

As described above, according to the gas engine control device,
When a sensor detects an abnormality in operation, the gas valve for supplying gas fuel is closed in response to the detection signal, so that the gas engine is reliably stopped and gas fuel is not wasted after the engine is stopped.

〔Effect of the invention〕

The present invention provides a gas engine that operates with gas fuel supplied through a gas valve as described above, in which the gas engine is provided with a sensor that detects the operating status of the rotating BS, and an abnormal operation signal detected by the sensor is used. Since the gas valve is configured to close, when an abnormal operation occurs, the engine is reliably stopped by cutting off the gas fuel, and the gas fuel is not continuously supplied after the stop, so there is no wastage.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a gas engine control device according to an embodiment of the present invention, Fig. 2 is an electronic circuit diagram for gas valve control by the same control device, and Fig. 3 is a flow chart diagram of control by the same control device. be. 1... Gas engine, 2... Intake pipe, 4...
・Gas valve, 9...Cooling water temperature sensor, 1o・
...Engine rotation speed in centimeters, 11.. Lubricating oil sensor, 16.. Engine control device, 17.. Control unit, 21.. Drive circuit.

Claims (2)

[Claims] (1) In a gas engine that is operated with gas fuel supplied through a gas valve, a sensor is installed in the gas engine to detect operating conditions such as rotation speed, and the gas valve is activated based on an abnormal operation signal detected by the sensor. A gas engine control device characterized by having a closed configuration. (2) The gas engine control device according to claim 1, further comprising an engine rotation speed sensor, a cooling water temperature sensor, and a lubricating oil sensor as sensors for detecting operating conditions.