KR100199579B1 - Elimination apparatus for hydrocarbon emission of exhaust gas in a car - Google Patents

Abstract

A ring-shaped groove 11 formed around the exhaust valve seat 6 in the gasoline engine, a plurality of small holes 13 penetrating the inner wall 2 of the exhaust pipe around the groove 11, and a ring-shaped groove 11; There is provided an apparatus for reducing hydrocarbon emissions in automobile exhaust gas, which comprises an air hole 15 communicating with an outer wall 7 of an engine body and an external air injection nozzle 17 provided at an inlet of the air hole. Preferably, the external air supply device for reducing the HC causes the external compressed air to be injected into a plurality of holes of the annular groove formed around the exhaust valve seat during the opening of the exhaust valve by the ECU's time control output signal. Since the large amount of HC is immediately oxidized in the exhaust port, there is an advantage that can reduce HC more effectively.

Description

Hydrocarbon Emission Reduction Device for Automobile Exhaust

1 shows a ring-shaped groove formed around the exhaust valve, a plurality of small holes penetrating the inner wall of the exhaust pipe formed around the groove, an air hole communicating the groove with the outer wall of the engine body, and an inlet of the air hole. Schematic cross section showing an external air supply device consisting of an external air injection nozzle.

FIG. 2 is a graph showing changes in HC concentration and HC emissions around an exhaust valve in an exhaust stroke of a gasoline engine. FIG.

* Explanation of symbols for main parts of the drawings

2: exhaust pipe inner wall 3: exhaust valve head

5: Intake valve head 6: Valve seat

11: annular groove 13: hole

17: injection nozzle 19: solenoid valve

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for reducing hydrocarbon emissions in automobile exhaust gas, and more particularly, to an apparatus for reducing hydrocarbon emissions in exhaust gas by oxidizing a large amount of hydrocarbons produced by combustion from a combustion chamber around an exhaust valve of an engine. It is about. In general, automobile exhaust gas refers to a gas discharged to the outside atmosphere through exhaust valves and exhaust pipes after a mixture of fuel and air is combusted in an engine cylinder. It is known that harmful oxides include lead oxides and carbon particles of weak acids in addition to carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NO _X ). The reduction targets for pollution prevention are mainly CO, HC and NO _X. Emission level of exhaust gas in the CO and HC in the petrol engine is largely dependent upon the mixing ratio of NO _X emission concentration is largely determined by the combustion temperature.

As a countermeasure for reducing harmful gas in gasoline engines, the apparatus used in the exhaust system besides the intake system and the fuel system is, for example, a secondary air supply device and a three-way catalytic converter. The secondary air supply device is designed to further reduce the content of CO and HC by purifying CO and HC in the exhaust gas through the catalyst in the exhaust system, and according to the negative pressure generated when the valve overlaps using exhaust pulsation. The opening and closing reed valve is installed in the middle of the pipe communicating between the exhaust manifold and the air purifier. When the inside of the exhaust manifold is negative pressure, the reed valve opens and fresh air is supplied from the air cleaner. The HC was reduced by oxidizing it with additionally supplied secondary air.

In particular, the experimental results revealed in the literature as a result of the previous research (refer to document name, article name, author, publication date), as shown in the graph of Fig. 2 of the accompanying drawings, the 1200 rpm and the throttle opening angle in the gasoline engine is 1.2 When the exhaust valve is opened and closed in the engine exhaust stroke, the HC concentration and HC emissions are measured according to the crank angle.The curve indicating HC emissions immediately after the opening of the exhaust valve (O) and HC It can be seen that the change in the curve (b) indicating the concentration is large.

The present invention is based on the fact that the emissions of HC are greatly increased immediately after the exhaust valve is opened in the gasoline engine as described above, by injecting a large amount of air around the exhaust valve in accordance with the opening time of the exhaust valve. It was developed to effectively reduce a large amount of HC.

According to the present invention, in order to inject a large amount of air around the exhaust valve, a ring-shaped groove is formed by the molding method along the inside of the outer periphery of the valve seat when the engine is manufactured, and a plurality of small holes penetrating the inner wall of the exhaust pipe around the groove. After forming the air hole, the air hole communicating with the groove and the outer wall of the engine main body is formed, and an external air supply nozzle is provided at the inlet of the air hole.

The external air injection nozzle may be used by being connected to the secondary air supply pipe of the secondary air supply device described above, but it is preferable to use compressed air generated in a separate air compressor to obtain a better effect. In addition, the front of the injection nozzle is provided with a solenoid valve for supplying and blocking the compressed air. The solenoid valve is time-controlled by the electrical output signal of the ECU to supply compressed air in time for opening the exhaust valve.

Accordingly, the present invention allows the external compressed air to be supplied to the injection nozzle through a solenoid valve that is time-controlled from the ECU while a large amount of HC is discharged from the exhaust valve, and the external air is supplied through the hole around the exhaust valve seat. It is possible to immediately oxidize a large amount of HC generated by combustion from the combustion chamber in the surrounding and exhaust ports, thereby providing more effective HC reduction measures.

To facilitate understanding of the objects, features and advantages of the present invention described above, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 1, there is shown an external air supply system installed around an exhaust valve 3 of an engine in accordance with the present invention. The external air supply device includes a ring-shaped groove 11 formed around the engine exhaust valve seat 6, a plurality of small holes 13 passing through the exhaust pipe inner wall 2 around the groove 11, and the groove 11. ) And an air hole 15 communicating with the outer wall 7 of the engine body, and an external air injection nozzle 17 provided at the inlet of the air hole.

The ring groove 11 is formed by a casting method along the inside of the outer circumference of the valve seat 6 when the engine is manufactured, and a plurality of ring grooves 11 penetrate the inner wall 2 of the exhaust pipe adjacent to the valve seat around the annular groove 11. After the small hole 13 is formed, an air hole 15 is formed in which the groove 11 and the engine body outer wall 7 communicate with each other. An injection nozzle 17 is provided at the inlet of the air hole 15, and the inlet of the injection nozzle is connected to the outlet of the air compressor 20 through the air pipe 18. A solenoid valve 19 for supplying and blocking compressed air in front of the injection nozzle 17 is installed in the middle of the air pipe 18. The solenoid valve 19 is opened and closed by an output signal generated by the electronic control unit ECU to supply compressed air at the time when the exhaust valve 3 is opened.

In the figure, reference numeral 9 denotes a piston of the engine, and 4 and 5 denote valve guides and intake valve heads, respectively.

In the external air supply device around the engine exhaust valve head having the above configuration, the high pressure air generated by the air compressor 20 is transferred to the injection nozzle 17 through the solenoid valve 19 controlled to be opened and closed by the output signal of the ECU. Supplied. That is, the ECU generates a drive signal voltage for opening the solenoid valve 19 in accordance with the period in which the exhaust valve 3 is opened in the gasoline engine.

The air injected from the injection nozzle 17 flows into the annular groove 11 through the air hole 15, and the outside air is exhausted through the hole 13 formed around the exhaust spit sheet 6. 3) It is ejected to the surroundings. Therefore, a large amount of hydrocarbons generated by the combustion from the combustion chamber around the exhaust valve and in the exhaust port are oxidized together with the external supply air, even while the discharge of HC is greatly increased between the time of opening and closing the exhaust valve.

As described above, according to the present invention, while the large amount of HC is discharged from the gasoline engine, the external compressed air is injected around the exhaust valve seat by the time control signal from the ECU to immediately oxidize the large amount of HC and the external air. There is an outstanding effect that can reduce HC more effectively.

Claims (3)

A ring groove 11 formed along the circumference of the outside of the engine exhaust valve seat 6, a plurality of small holes 13 passing through the exhaust pipe inner wall 2 around the ring groove 11, and the ring groove An apparatus for reducing hydrocarbon emissions in a vehicle exhaust gas comprising an air hole (15) communicating with an outer wall (7) of an engine body, and an external air injection nozzle (17) provided at an inlet of the air hole (15). The inlet of the injection nozzle 17 is connected by an air pipe, and is installed in the middle of the air pipe and includes a solenoid valve 19 for supplying and blocking air from the compressed air tank. To reduce hydrocarbon emissions from automobile exhaust gas. 3. The motor vehicle according to claim 2, wherein the solenoid valve (19) is opened and closed by an output signal generated by an electronic control unit (ECU) for supplying compressed air in accordance with the opening period of the exhaust valve (3). Reducing hydrocarbon emissions from exhaust gases.