JPS6030443Y2 - Exhaust gas purification device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an exhaust gas purification device used in an internal combustion engine.

Recently, an internal combustion engine has been proposed in which two spark plugs are provided in a combustion chamber, and the two spark plugs ignite the air-fuel mixture in the combustion chamber.

The reason why the air-fuel mixture is ignited using these two spark plugs is that by stabilizing the combustion of the air-fuel mixture, sufficient output and reduction of exhaust gas can be achieved even with a lean air-fuel mixture.

Incidentally, even in this type of internal combustion engine, it is necessary to recirculate the exhaust gas, and simultaneously with the recirculation of the exhaust gas, it is also necessary to enrich the air-fuel mixture in accordance with the recirculation of the exhaust gas.

As described in U.S. Patent No. 3.507.2ω, this exhaust gas recirculation device uses negative pressure generated near the throttle valve as the throttle valve opens and the air flow rate increases. A method of controlling this is being considered.

Further, in conjunction with this, a fuel increase means such as a power valve mechanism is provided in the fuel passage of the carburetor to prevent a decrease in output due to the recirculation of exhaust gas.

However, in this purely mechanical-fluid control system, the amount of exhaust gas increases as the amount of intake air increases.

There is a problem with fuel not increasing in time.

Therefore, even if two spark plugs are provided in the combustion chamber to improve output and reduce exhaust gas, there is a fatal drawback in that the effects cannot be fully exploited due to the above-mentioned problems.

The purpose of this invention is to provide an exhaust gas purification device that can increase exhaust gas and fuel without delay as intake air increases in an internal combustion engine that has at least two spark plugs in the combustion chamber. A fuel control valve is installed in the fuel system of the engine, and an exhaust gas recirculation valve is installed in the exhaust gas recirculation passage, and an operating signal representing the operating state of the engine is input to the control circuit. and an electric actuator that drives the exhaust gas recirculation valve to increase exhaust gas and fuel when the operating signal indicates an increase in intake air.

An embodiment of the present invention will be described in detail below with reference to the drawings.

In the figure, 1 is the combustion chamber, 2 is the intake valve, 3 is the exhaust valve, 4.5 is the spark plug, 6 is the intake manifold, 7 is the carburetor, 8 is the venturi of the carburetor 7, and 9 is installed inside the venturi 8. 10 is the fuel nozzle of the carburetor,
11 is a float chamber of the carburetor 7, 12 is a fuel pump, 13
is a fuel tank, 14 is a throttle valve of the carburetor 7, 15 is an air cleaner, 16 is an air conduit, 17 is an air preheater, 18 is an air conduit, 19 is an exhaust gas recirculation valve, 20 is an exhaust gas conduit,
21 is the catalytic converter, 22 is the engine piston, 23
is a heating heater, 24 is a power battery for the heating heater 23, 25 is a switch for turning ON/OFF the heating heater 23, 26 is a temperature detector for detecting the temperature of the heated air,
27 is a fuel control valve that adjusts the fuel flow rate of the carburetor; 28 is an opening detector that detects the opening of the throttle valve 14 of the carburetor; 29
Reference numeral 30 indicates a control circuit, and 30 indicates an ignition device.

The catalytic converter 21 and the air preheater 17 are connected to the exhaust pipe 31
installed on.

Further, an exhaust pipe 20 is installed in the middle of the pipe 18 connecting the air preheater 17 and the small vent 9 of the vaporizer, and a heating heater 23 is installed downstream of the exhaust pipe 20.

It also detects the temperature of heated air.

Temperature detector 26 composed of a thermistor, bimetal, etc.
The signal operates the switch 25 via a relay, and the current of the heater 23 is turned off.

Further, an analog signal from the opening detector 28 consisting of a variable resistor etc. enters the control circuit 29, and an output signal corresponding to the input signal is sent to the actuator 27A of the fuel control valve 27, the actuator 30A of the ignition device 30, the exhaust gas recirculation valve 19, etc. The power is supplied to the actuator 19A so that each device can be electrically driven.

The ignition system 30 is composed of an ignition coil that operates the spark plug 4.5, a distributor, a point, an advance angle correction device, etc. In addition to normal rotation speed and advance angle correction based on suction negative pressure, the control circuit 29 The advance angles of the spark plugs 4 and 5 are independently corrected in accordance with the output signals of the spark plugs 4 and 5.

Further, two or more spark plugs 4 and 5 are installed at mutually distant positions on the wall surface of the combustion chamber 1.

The fuel tank 13 and fuel pump 12 are the same as in the conventional method.

Since the present invention is constructed as described above, its operation is as follows.

Part of the air taken into the engine is air cleaner 15
The air is supplied to the air preheater 17 through the conduit 16 from the downstream of the
When the engine is cold, such as immediately after starting, the heating heater is turned on by a signal from the temperature sensor 26. 23 operates to heat the air, so the temperature of the mixed gas supplied to the small vent lily 9 is always maintained at about 200°C.

Incidentally, since the fuel flowing out from the nozzle 10 is exposed to the above-mentioned high-temperature gas, it instantly vaporizes and is supplied to the combustion chamber 1 of the engine through the intake manifold 6.

The amount of these mixed gases is at most 15 to 2 of the total intake air amount.
Since it is about 0%, when the fuel is completely vaporized, the temperature of the mixed gas decreases due to the heat of vaporization, and the overall filling efficiency hardly decreases.

Two or more spark plugs 4.5 are installed in the combustion chamber 1, and the spark plugs 4. , 5 is set so that the output is high and the generation of nitrogen oxides is small, so the concentration of nitrogen oxides is significantly reduced compared to conventional engines, and the decrease in output is kept to a minimum. I can do it.

In addition, a proper air-fuel mixture is always formed in the combustion chamber 1 by instantaneous vaporization of the fuel, and is ignited by multiple spark plugs, allowing smooth operation with a lean air-fuel mixture with an air-fuel ratio of 2 degrees. This makes it possible to significantly reduce the concentrations of carbon monoxide and unburned hydrocarbons, maintain stable rotation even if the exhaust gas recirculation rate is increased, and prevent a decrease in output.

On the other hand, as the throttle valve 14 of the carburetor opens, the exhaust gas recirculation valve 19 is actuated by the actuator 19A by the action of the control circuit 29.
As the throttle valve 14 opens, the recirculation rate of the exhaust gas supplied to the engine increases, diluting the air-fuel mixture in the combustion chamber 1. , which reduces the combustion rate and suppresses the generation of nitrogen oxides.

Furthermore, when increasing the exhaust gas recirculation rate at high loads,
Under the action of the control circuit 29, the actuator 27A uses the fuel control valve 27 to enrich the air-fuel mixture from about 26 to 22, thereby improving the output.

In such an air-fuel mixture with an air-fuel ratio of 22 or higher, several percent of oxygen is contained in the exhaust gas, so
The catalyst can proceed with the reaction without supplying secondary air from outside the exhaust pipe using, for example, an air pump.

As described above, the present invention inputs an increase signal to a control circuit when intake air increases, and controls the exhaust gas control valve and fuel control valve by an electric actuator based on the output signal from this control circuit. Therefore, it is possible to obtain an exhaust gas purification device without any delay in operation, and to improve the effect of reducing toxic exhaust gases in an internal combustion engine having at least two spark plugs in its combustion chamber.

[Brief explanation of drawings]

The drawing is a schematic diagram of an exhaust gas purification device showing an embodiment of the present invention. 1... combustion chamber, 4, 5... spark plug, 6... curved intake manifold, 7... carburetor,
8.Song Venturi, 9...Small bench lily
, 13・Song・Fuel tank, 14... Throttle valve, 15
...Tune air cleaner, 17...Air preheater,
19... Exhaust gas recirculation valve, 19A...
Actuator, 21...Catalytic converter,
23... Heater, 26... Temperature detector, 27... Fuel control valve, 27A...
...Actuator, 28...Opening degree detector, 2
9... Control circuit, 30... Ignition device.

Claims (1)

[Scope of utility model registration request] a carburetor that supplies fuel and air to an engine combustion chamber; an exhaust pipe that ignites and burns the mixture in the combustion chamber and then discharges exhaust gas from the mixture combusted in the combustion chamber; In an internal combustion engine comprising at least two spark plugs provided at positions apart from each other on the wall surface of the combustion chamber, and an ignition timing control means for controlling the ignition timing of the spark plugs, the fuel supplied from the carburetor is controlled. A fuel control valve for controlling the amount of exhaust gas is provided in the carburetor, and a recirculation amount of exhaust gas is provided in the middle of the exhaust gas recirculation passage for re-inhaling a part of the exhaust gas discharged from the exhaust pipe into the combustion chamber. An exhaust gas recirculation valve is provided to control the internal combustion engine, and an operating signal representing the operating state of the internal combustion engine is input to the control circuit as an electrical input signal, and at the same time, an electrical output signal based on the input signal is sent from the control circuit. an electric first actuator for driving the fuel control valve and a second electric actuator for driving the exhaust gas recirculation valve; When the amount of fuel and exhaust gas passing through the fuel control valve and the exhaust gas recirculation valve is increased, the first and second actuators are operated to increase the amount of fuel and exhaust gas passing through the fuel control valve and the exhaust gas recirculation valve.