JPH05214979A - Light-load operation preventing circuit - Google Patents

Abstract

PURPOSE:To automatically control the load state of an engine invariably properly by detecting the fuel consumption of the engine on an engine generator, judging the load state of the engine, and automatically releasing or applying a pseudo load in response to the fluctuation of the load state. CONSTITUTION:An automatic/manual selector switch 13 for controlling a pseudo load is switched to the side A, and the automatic mode exciting a relay 14 is selected. When the power consumption of a load facility 5 is decreased to a preset value during the operation of an engine generator 1A, for example, contacts 8-1, 8-2 of a fuel consumption measuring unit 8 for an engine 1 are closed. The coil 26 of the insertion electromagnetic contactor 11 of a pseudo load 12 is excited by actions of the plus side of a DC power source 32, the A-contact of the relay 14, and the contacts 8-1, 8-2 via the A-contact 22 and B-contact 24 of a relay section 6A. Both the load facility 5 and the pseudo load 12 are connected, and the engine 1 is prevented from being operated in the light-load state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light load operation prevention circuit for an engine in a power supply system in which a generator is rotated by driving the engine to obtain a power generation output.

[0002]

2. Description of the Related Art Conventionally, this type of engine light load operation prevention circuit detects an AC output current (apparent current) of an engine generator and automatically turns on a pseudo load at about 25% of the rated output current. The light load was prevented. Also, the pseudo load was opened when the output current increased to about 75% of the rated value. Since the apparent current of the generator output is detected by this method, even if the load applied to the engine changes depending on the load power factor, the difference in engine load cannot be grasped. For example, apparent power / effective power consumption is 10KVA / 6KW load and 10KV
Although the load amount applied to the engine is different under the load of A / 8 KW, since the apparent currents are the same, it is determined that the load amount is the same, and the control of turning on and off the pseudo load is performed. Thus, when the engine is used under a light load, the fuel causes incomplete combustion and carbon adheres to the nozzle of the fuel injection pump section. When used for a long time in this state, the horsepower of the engine had decreased.

[0003]

Since the above-mentioned conventional light load operation prevention circuit detects the apparent current of the generator output, it has a drawback that the load amount of the engine itself cannot be grasped.

The object of the present invention is to focus on the fact that the fuel consumption amount is proportional to the output horsepower of the engine, and by detecting the fuel consumption amount of the engine, a light load operation circuit capable of grasping the presence or absence of the light load state of the engine is provided. To provide.

[0005]

The light load operation prevention circuit of the present invention comprises a fuel consumption detector for detecting the fuel consumption of the engine when the engine is operating under a light load or a heavy load, and When the fuel consumption detector detects a fuel consumption corresponding to a light load of the engine's rated output horsepower, a pseudo load is automatically applied and the fuel consumption is detected again when the engine load increases to a heavy load. And a control circuit for automatically releasing the pseudo load.

[0006]

The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention.

Next, the configuration and operation of this embodiment will be described. In FIG. 1, while the engine (ENG) 1 and the generator (G) 2 are operating, AC power is supplied to the load equipment 5 via the circuit breaker 3 and the electromagnetic contactor 4. Engine 1
Fuel is supplied from the fuel tank 9 through the fuel pipe 7 and the measuring device 8 for detecting the fuel consumption amount.

Next, the case of the automatic mode in which the automatic manual changeover switch 13 for controlling the pseudo load is selected to the A side and the relay 14 is excited will be described. Engine generator 1A
When the power consumption of the load equipment 5 during operation decreases and the value decreases to about 25% of the engine rated horsepower, the contacts 8-1 and 8-2 of the measuring instrument 8 for measuring the fuel consumption are closed. , As a result, DC power supply plus, relay A contact 6,
The operation of the contact 8-1 and the contact 8-2 excites the coil 26 of the electromagnetic contactor for closing the pseudo load 12 through the A contact 22 and the B contact 24 of the relay section 6A, so that the electromagnetic contactor 11 is closed. The pseudo load 12 is connected to the engine generator output. That is, since both the load equipment 5 and the dummy load 12 are connected, the engine output horsepower is 25% or more, and it is possible to prevent the engine from operating in a light load state.

Next, the load equipment 5 is connected with the dummy load 12 connected.
When the electric power of the relay 8-2 increases to 75% of the engine rated horsepower, the relay 8-2 changes from the closed state to the closed state, the excitation of the coil of the electromagnetic contactor 52D is released, and the pseudo load 12 generates the engine. It is separated from the machine output. When the changeover switch 13 is selected to the manual mode M side, the pseudo load 12 can be freely connected to the engine generator output according to the judgment of the maintenance staff regardless of the load amount of the engine.

[0010]

As described above, according to the present invention, by detecting the fuel consumption of the engine of the engine generator, the load condition of the engine is grasped, and the load applied to the engine is the rated output horsepower of the engine. If it is less than about 25%, the pseudo load will be automatically applied and the load will be appropriate and the engine can be protected. Further, when the load applied to the engine increases to about 75% of the rated output horsepower of the engine, the pseudo load is automatically released, so that the load of the engine can be automatically controlled to an appropriate value. ..

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention.

[Explanation of symbols]

1 Engine 1A Engine Generator 2 AC Generator 1A En 3,10 Circuit Breaker 4,11 Electromagnetic Contactor 5 Load Equipment 6A Relay Section 7 Fuel Pipe 8 Fuel Consumption Detector 6,8-1,8-2,16, 18, 20-26, 27,
29 contacts 9 fuel tank 12 pseudo load 13,28 changeover switch 14, 17, 15, 19 relay 26 exciting coil 30, 33 indicator 32 DC power supply

Claims (2)

[Claims] 1. A fuel consumption detector for detecting the fuel consumption of the engine when the engine is operating under a light load or a heavy load, and the fuel consumption detector has a light output horsepower of the engine. When the fuel consumption corresponding to the load is detected, the dummy load is automatically turned on, and when the engine load increases to a heavy load, the fuel consumption is detected again and the dummy load is automatically released. Light load operation prevention circuit characterized by being equipped with. 2. The light load operation according to claim 1, wherein a built-in power source for operating the control circuit is brought into a connected state by turning on a relay contact attached to the fuel consumption detector to operate the control circuit. Prevention circuit.