JPH0355774Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial field of application> This invention belongs to the technical field of catalytic exhaust gas treatment devices for low-volatility liquid fuel engine generators, and uses low-volatility liquid fuel as its prerequisite structure. The generator G is driven by the engine E used as fuel, and the generated power is supplied to external load equipment from the power output terminal 22 of the output circuit 23. A heater 8 and a catalyst 9 are connected to the exhaust system of the engine E. and engine E
The exhaust gas discharged from the combustion chamber is heated by a heater 8 and then brought into contact with a catalyst 9, thereby burning unburned components in the exhaust gas.

<Technical Background> In recent years, due to demands for energy conservation and resource conservation, it has become desirable to use inexpensive kerosene and other alternative fuels as engine fuel instead of expensive gasoline.

However, compared to gasoline, these alternative fuels are difficult to vaporize and have a high ignition temperature, resulting in poor combustion efficiency and problems such as unstable engine rotation or stalling at no or light loads.

This difficulty becomes more pronounced as the rotational speed is lower, the cylinder volume is smaller, and in two-stroke engines than in four-stroke engines.

<Prior Art> Conventionally, there is a technology in which a kerosene engine is started with gasoline and operated with kerosene.

On the other hand, there is a technology in which a heater and a catalyst are provided in the exhaust system of the engine, and the exhaust gas discharged from the combustion chamber is heated by the heater and then brought into contact with the catalyst, thereby burning unburned components in the exhaust gas. It is disclosed in Japanese Patent Application Laid-Open No. 117121/1983. Using these technologies, it is possible to stabilize engine rotation by switching from kerosene to gasoline during no-load or light-load conditions, while also effectively burning unburned substances in exhaust gas. .

<Problems to be solved by the invention> In this case, in addition to the kerosene supply system, a gasoline supply system and an automatic fuel switching device are additionally required, which complicates the structure and consumes expensive gasoline.

On the other hand, in the catalytic exhaust gas treatment device disclosed in JP-A-53-117121, the heater is turned on and off continuously or at predetermined time intervals, or when the back pressure of the catalytic muffler reaches a predetermined level. Because the heating operation is performed when the engine is under medium or high load, the heating operation continues uselessly even when the engine is under medium or high load, and the heating by the heater is added to the temperature rise of the catalyst due to the combustion of unburned substances, sometimes causing the catalyst to overheat. Accidents that lead to fire damage also occur.

This invention stabilizes engine rotation while using low-volatile liquid fuel such as kerosene, and also avoids giving extra fuel during medium to high loads when engine rotation is stable. The purpose is to increase output and fuel efficiency, and to prevent catalyst burnout accidents.

<Means for solving the problem> In order to achieve the above purpose, the present invention applies an extra load during no load or light load to slightly increase the amount of fuel supplied, and uses a heater as the extra load. This heater heats the exhaust gas discharged from the combustion chamber of the engine and then brings it into contact with a catalyst to effectively burn the unburned components in the exhaust gas, and has the basic structure described above. In a catalytic exhaust gas treatment device for a low vaporization liquid fuel engine generator, a heater is connected to the output circuit of the engine generator, and a switch for turning the heater on and off is controllably connected to the load detection circuit of the output circuit. The load detection circuit turns on the switch to activate the heater to generate heat based on detecting no load or light load, and turns off the switch to activate the heater to generate heat based on detecting medium or high load. This feature is characterized in that it is configured to be stopped.

<Operation> When the load acting on the generator becomes no load or light load, the load detection circuit detects this and turns on the switch, causing the heater to generate heat.

Then, the engine is given an extra load by the amount of heat generated by the heater, and the amount of fuel supplied is increased.
The engine temperature during operation is kept high, and the amount of air-fuel mixture supplied is kept relatively large, reducing the rate at which fuel particles in the air-fuel mixture adhere to the walls of the intake passage.

As a result, the low-volatile liquid fuel is vaporized well and burnt efficiently, allowing the engine to rotate stably.

On the other hand, the heat generating operation of the heater raises the exhaust gas to the reaction temperature of the catalyst, causing the unburned components in the exhaust gas to undergo a sufficient catalytic reaction, thereby effectively burning them.

Also, when the load acting on the generator becomes a medium load or a high load and rotates stably, this is detected and the heater is stopped.

This eliminates the power consumption of the heater, eliminates the reduction in engine fuel efficiency and output, and
Since the heating of the exhaust gas by the heating of the heater is stopped, the temperature of the catalyst remains at the temperature caused by the combustion of unburned gas, thereby eliminating the risk of catalyst burnout.

<Example> Hereinafter, an example according to the present invention will be described based on the drawings.

FIG. 2 is a side view of a low-volatility liquid fuel engine generator equipped with a catalytic exhaust gas treatment device according to the present invention.

The engine generator is configured to be portable by directly connecting the engine E and the generator G to a frame 1 made of pipe. It has become something that can be produced.

In the figure, numeral 3 is a fuel tank, 4 is an air cleaner, 5 is a carburetor, and 6 is a recoil starter.

This engine E uses a two-stroke engine that uses kerosene as fuel, and as the piston moves up (not shown), the air-fuel mixture from the carburetor 5 is sucked into the crank chamber through a valve and an intake passage.
As the piston descends, exhaust gas is sent from the crank chamber through the wall passageway into the combustion chamber from the scavenging outlet in the cylinder, thereby sending exhaust gas to the muffler device M from the exhaust port.

3 and 4 are enlarged views of the muffler device shown in FIG. 2, and in these figures, 7 is a catalyst muffler, and 10 is a muffler.

The catalyst muffler 7 includes a heating chamber 7a which has a built-in heater 8 and heats exhaust gas, a catalyst chamber 7b which has a built-in catalyst 9 and which burns non-combustibles in the exhaust gas by its catalytic action, and a heating chamber 7a which has a built-in heater 8 and which heats exhaust gas, a catalyst chamber 7b which has a built-in catalyst 9 and which burns non-combustibles in the exhaust gas by its catalytic action, and a heating chamber 7a which has a built-in heater 8 and which heats exhaust gas. It is divided into a chamber 7c for introducing exhaust gas into the muffler 10.

As shown in FIG. 4, a communication pipe 13 communicates the heating chamber 7a and the exhaust port 11 of the engine E.
A protruding pipe 12 having the same diameter as the exhaust port 11 is provided protruding therein, and an end 14 of a conduit 14 for introducing air from the air cleaner 4 into the pipe wall of the communicating pipe 13.
A is opened and a reed valve 15 is installed there. Air is introduced by the negative pressure generated by the flow of exhaust gas discharged from the protruding pipe 12, and this air is heated together with the exhaust gas by the heater 8, and the unburned content becomes catalytic. This replenishes the oxygen required during combustion. The temperature required for the catalytic reaction is about 300°C or higher, but the temperature of the exhaust gas at no load or light load is about 200°C, so the catalytic reaction can be accelerated by heating the exhaust gas with the heater 8. It can be promoted.

Figure 1 shows a circuit diagram of the heater drive control device,
The heater 8 is connected to be operated by electric power from the generator G, and the switch 20 that controls energization and stopping of the heater 8 is configured to be operated and controlled based on the detection result of the load detection path 21 of the output circuit 23. has been done.

The load detection circuit 21 detects the load current of the output circuit 23, and if the result is less than a predetermined low current, a command is issued to turn on the switch 20 and energize the heater 8, thereby reducing the load current. When the value exceeds the predetermined value, a command is issued to turn off the switch 20 and stop energizing the heater 8.

That is, the symbol T in FIG. 1 is a current transformer that detects the load current of the output circuit 23, and CI is a comparator that compares the current value detected by the current transformer T with a predetermined current value and opens and closes its output terminal. , Tr ₁
and Tr ₂ is a transistor for turning on and off the switch 20 according to the output signal of the comparator CI;
AI is the constant voltage power supply section of the load detection circuit 21, R ₁ , R ₂
are each a predetermined resistance.

To explain the operation of the load detection circuit 21, when there is a light load or no load (hereinafter simply referred to as no load), no AC load current flows through the output circuit 23 and there is no input to the comparator CI, so the output voltage is zero.
becomes. Therefore, a potential difference is generated across the resistor _R1 , and a current I flows through the base and emitter of the transistor _Tr1 , where it is amplified.The current then flows through the base and emitter of the transistor _Tr2 , causing the amplified current Is to flow. , this current Is causes switch 2
By turning on 0, the heater 8 is activated to generate heat.

When a load is connected to the power output terminal 22 of the output circuit 23, the AC load current causes the current transformer T to output a current It, which is input to the input terminal of the comparator CI, and the current value It becomes a predetermined value. If it exceeds the standard value established based on medium to high loads,
When a voltage is generated at the output terminal and the potential difference between both ends of the resistor _R1 becomes O, no current flows between the base and emitter, and eventually the transistors _Tr1 and _Tr2 turn off.
By turning off the switch 20, the heater 8
The fever stops.

<Effects of the invention> As explained above, according to the invention, when the load acting on the generator is low to no load,
By detecting this and energizing the heater, it is possible to apply a predetermined load to the engine and stabilize the engine rotation.Furthermore, the heat generated by the heater heats the exhaust gas and promotes the reaction of the catalyst. Unburned components in exhaust gas can be effectively combusted.

As a result, when the engine is operated with kerosene or other low-volatility liquid fuel, it can be operated stably using low-volatility liquid fuel even at low or no load, and the fuel can be switched to gasoline. This eliminates the need for gasoline supply systems and automatic fuel switching devices, and also eliminates the need to consume expensive gasoline.

In addition, under medium and high loads, the power supply to the heater is stopped to prevent unnecessary output loss and reduction in charging efficiency, thereby preventing output loss and fuel loss. Since the catalyst is not overheated by the heat of the catalyst, it has excellent effects such as being able to prevent catalyst burnout accidents.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a circuit diagram of a heater drive control device, Fig. 2 is a side view of the entire low-volatile liquid fuel engine generator, and Fig. 3 is a diagram of the muffler device in Fig. 2. The enlarged side view and FIG. 4 are plan views of the muffler device. E... Engine, G... Generator, M... Muffler device, 8... Heater, 9... Catalyst, 10... Silence muffler, 20... Switch, 21... Load detection circuit, 22... Power extraction Terminal, 23...output circuit.

Claims (1)

[Scope of Claim for Utility Model Registration] A generator G is driven by an engine E that uses low-volatile liquid fuel as fuel, and the generated power is output to a circuit 23.
A heater 8 and a catalyst 9 are provided in the exhaust system of the engine E, and the exhaust gas discharged from the combustion chamber of the engine E is heated by the heater 8. In the catalytic exhaust gas treatment device for a low-volatility liquid fuel engine generator configured to combust unburned components in exhaust gas by bringing the generator G into contact with the catalyst 9, the output circuit 23 of the generator G is A heater 8 is connected, and a switch 20 for turning on and off the heater 8 is controllably connected to a load detection circuit 21 of an output circuit 23, and the load detection circuit 21 switches the switch 20 based on detecting no load or light load. is turned on to cause the heater 8 to generate heat, and the switch 20 is turned off to stop the heater 8 from generating heat based on medium or high load detection. Catalytic exhaust gas treatment equipment for fuel engine generators.