WO2001050017A1

WO2001050017A1 - Ignition plug for internal combustion engines

Info

Publication number: WO2001050017A1
Application number: PCT/KR2000/000342
Authority: WO
Inventors: In Tae Johng; Jong Hoi Kim; Jung Dae Yoon
Original assignee: In Tae Johng; Jong Hoi Kim; Jung Dae Yoon
Priority date: 1999-12-30
Filing date: 2000-04-12
Publication date: 2001-07-12
Also published as: KR100328490B1; KR20010058770A; AU4148300A; JP2003519431A; KR200184909Y1; DE10085370T1

Abstract

An ignition plug for use in an electric firing type internal combustion engine includes a hollow tubular main cell (210) a pair of electrodes (230) comprising a center electrode mounted in the hollow lower end of the main cell, and a ground electrode integrally formed in the lower end of the main cell in correspondence to the center electrode and a pre-combustion chamber (250) formed in the lower end of the main cell, for accommodating part of a fuel-air mixture and combusting the same, in order to fire and combust a remaining portion of the fuel-air mixture compressed in a combustion chamber within a shorter time using an explosive spark flame of a small scale which occurs when the part of the compressed fuel-air mixture is fired and combusted in advance at the time of an ignition time of the engine. The ignition plug includes a small pre-combustion chamber which can be integrated with or separated from the lower end thereof, and thus fires and combusts in advance a little amount of fuel-air mixture taken into the pre-combustion chamber during a compression stroke of the engine. Also, the fuel-air mixture can be combusted within a much shorter time than the conventional art. As a result, it is possible to use a lean mixture in the electric firing type internal combustion engine to thereby save fuel in use and enhance a combustion efficiency of the engine. Also, an exhaust gas harmful to the human body is reduced to thereby provide a merit of reducing a complex air pollution.

Description

IGNITION PLL G FOR INTERNAL COMBUSTION ENG INES

DESCRIPTION

Technical Field

The present invention relates to an electric tiling ty pe internal combustion engine, and more particular!} , to an ignition plug in which part ot compressed fuel-air mixture is primarily fired and combusted, the remaining whole part of fuel-air mixtuie in a combustion chamber is quickly and surely burnt due to the extended flame, and also the whole fuel-air mixture is sequentially combusted within a shorter time, to thereby remarkably shorten an overall combustion time

Background Art

Generally, a thermal engine is an apparatus for changing a thermal energy into a mechanical work The thermal engine is largeh classified into an internal combustion engine and an external combustion engine, according to a type for supplying thermal energy for an operating material such as a fluid used for changing a thermal energy into a mechanical work The internal combustion engine pertorms a combustion work inside the engine, in which a chemical energy possessed

the fuel- air mixture formed of a mixture of a fuel such as gasoline and clean air is changed into a thermal energy by the combustion, and a work obtained when the combustion gas is expanded is directly used The internal combustion engine is largeh classified into a 4-stroke cycle engine and a 2-stro e cycle engine according to the operating method In the case of the 4-stroke cy cle engine, one cy cle ot intake, completion, power and exhaust is accomplished with two rotations of a crankshaft, that is. tour strokes ot a piston

One example of the 4-stroke cycle engine is schematically shown in FIG 1 As shown in FIG. 1. the electric firing type internal combustion engine 10 includes a cylindrical cylinder 1 1. a piston 12 which is tightly accommodated in the hollow ot the cylinder 1 1. a crankshaft 14 which is connected to the lower portion of the piston 12 by a connecting rod 13. and an intake valve 15. an exhaust va e 16 and an ignition plug 1U0 which are mounted on the upper portion of the c linder 11 \lso. on the upper portion ot the cylinder 11 are formed an intake hole 17 and an exhaust hole 1 In the case that the electric firing type internal combustion engine 10 has a 4- stroke cycle, it is dnven by an operating mechanism formed ot intake, compression, power and exhaust strokes, thereby creating power Here, at the intake stroke, the tuel-air mixture is taken into the cylinder 11 when the piston 12 talks down from a top dead center (TDC). that is. a point where the piston 12 goes up to the top and goes down again, at the state where the intake valve 15 opens the intake hole 17 λt the compression stroke, the piston 12 goes up to compress the fuel-air mixture so that pressure and temperature of the fuel-air mixture simultaneously rise up to then be evaporated, at the state where the intake valve 15 closes the intake hole 17 and the exhaust vahe 16 closes the exhaust hole 18. At the power stroke, the ignition plug 100 fires the fuel-air mixture and the piston 12 goes down owing to pressure of the high pressure gas generated by combustion of the fuel-air mixture, to thereby apply a rotational force to the crankshaft 14. a little before the TDC where the compression stroke is completed At the exhaust stroke, the piston 12 goes up so that the combustion gas is exhausted outside the cylinder 11. at the state where the exhaust 16 opens the exhaust hole 18 When the piston 12 reaches the TDC. another cycle is repeatedly performed from the intake stroke.

Here, at the power stroke after the compression stroke of the electric firing type internal combustion engine, the fuel-air mixture is fired and combusted with an electric spark which is made by an ignition plug. One example of the ignition plug is shown in FIG.2 λ shown in FIG 2. the conventional ignition plug 100 includes a cell 111), an insulator 120. and a pair of electrodes 130 opposing each other and having a respectively different polarity according to a power source The cell 110 is formed as a substantially cylindrical shape with threads 112 formed around the lower portion thereof and a hollow inside. A rod-shaped insulator 120 is tightly installed in the hollow of the cell 110. The insulator 120 is installed in the cell 110 at the state where a center electrode 132 of the pair of electrodes 130. a shaft rod 144 spaced a predetermined distance apart upwards from the center electrode 1 32. and part of the terminal connected to the upper end of the shaft rod 144 are simultaneously coated by the insulator 12(J Here, part of the lower end ot the center electrode 1 32 is exposed out the lower end ol the insulator 1 20 Meanwhile, a ground electrode 1 34 hav ing a substantially L-shaped protrude is integrally formed in the low er portion of the cell 1 10

The ignition plug 100 forms a part of an ignition apparatus of the electric tiring ty pe internal combustion engine, together w ith a rechargeable battery , an ignition coil. a distributor, a high pressure cable, etc.. which are unshown The ignition plug 100 fires the fuel-air mixture of gasoline and air which are taken in the combustion chamber 20 of the cylinder 1 1 and compressed at the compression stroke of the cycle, with the electric spark due to an electric arc of the center electrode 1 32 and the ground electrode 134. so that the fuel-air mixture is fired and continuously combusted. As a result, the power stoke of the engine 1 0 is performed, and the engine 10 is continuously rotated due to the expanded pressure.

As described abov e, in the case of the electric firing ty pe internal combustion engine, efficiency and performance of the engine are greatly varied according to an operating point of the ignition plug 100. that is. an ignition timing for firing an electric spark, which will be described with reference to FIG. 3.

The graph oi^' FIG. 3 is a combustion-pressure curve of an engine output indicating a relationship between an angle of a crankshaft and a pressure in the cylinder, from the technical specification with respect to an electric firing t pe internal combustion engine of Bosch in Germany, in which a pressure change in the combustion chamber is indicated w ith the range of about 75 ^' before and after the TDC of the crankshaft angle assuming that the TDC is 0^r as a reference.

In addition, in the graph, pressure curv es 1 . 2 and 3 show a pressure change m the combustion chamber with respect to the crankshaft angle, respectiv ely in the cases that ignition timings are T l . T2 and T3. As can be seen from the graph, the compressed fuel-air mixture in the cy Under is fired w ith a spark of the ignition plug and then exploded. In this case, it takes a little time until a pressure reaches a maximum value. An inter al from a point 1 at w hich the fuel-air mixture is fired to a point 2; is an interv al at w hich there is a little rise of the pressure due to the combustion, which corresponds to a combustion delav ^ i nterv al or a combustion preparation interval. The combustion delay interv al is constant as about 1 '600 seconds irrespective of the rotational number of the engine, if the fuel and load are not changed. Thus, if the engine rotates faster, the crankshaft angle a l during the interval L-.2. becomes large. As the engine rotates faster, the ignition timing 1 should be earlier. An interval 2, -A is an interval at w hich a

K) pressure rises up due to the combustion, which corresponds to a pressure rise-up interv al. If the engine rotates faster, the pressure rise-up becomes faster due to a turbulent stream of the fuel-air mixture in the cylinder. Accordingly, a time consumed for the interval ^"2A3 is shortened. However, if the engine rotates faster, a rotational angular velocity of the crankshaft becomes faster. As a result, a

15 crankshaft angle a2 during the interval AA3: is nearly constant irrespectiv e of the rotational number of the engine.

Also, in the electric firing ty pe internal combustion engine, the highest engine output is generated at an ignition timing point T2. and the lowest engine output is generated at an ignition timing point T3. This can be ascertained from the fact that 0 the pressure curve 2 is positioned at the highest and the pressure curve 3 is positioned at the lowest.

As described above, in the electric firing type internal combustion engine, the crankshaft variation angle al during the interval 1 - 2 is proportional w ith the rotational number, and the crankshaft variation angle a2 during the interv al - .! is

25 nea constant irrespective of the rotational number. Therefore, the ignition timing should be faster in proportion to an increase of the rotational number. Also, as the load of the engine becomes smaller, a throttle valve of a carburetor is opened a little. As a result, an intake efficiency is lowered and a compression pressure becomes low. For this reason, since a combustion time becomes long, an ignition timing should be

30 earlier. Thus in the pπoi art. a distri butor timing in the ignition appar atus is set so that an ignition timing point the electnc firing ty pe internal combustion engine is aiound -55 " on the crankshaft angle during high speed rotation, and the toi mei is ai ound - A on the latter during low speed rotation w hen the I DC 0 is a relei ence Vccordingly. a torque genei ated in the engine and an efficiencv of the engine hav e been maximized

Flυwev ei. in the case that the engine efficiency is maximized, and m the ease ot the ignition timing point T2 set as the ignition timing point eonsidei ing a high speed rotation ot the engine, a complex combustion, that is. a knocking tendency, may occui m the same cy hndei whei e another combustion stroke occurs abnoi mally during a single piston reciprocation cy cle before and after the TDC As a result, inegulai explosion noise occurs during operation, and a life cycle of the engine may be shortened due to a breakage of the engine or a decrease of duiabiluy Also, m the case that a lean mixture whose mixture ratio of fuel and air is 1 16- 1 19 is taken in during high speed rotation of the engine, a firing or combustion mfeuority frequently occurs Thus, there is a limitation to make an ignition timing earliei than the TDC ot the crankshaft angle, in ordei to heighten an engine output

Also, in the electric firing ty pe internal combustion engine, the ignition timing point T3 set as the ignition timing point during low speed rotation is shown as the pressure cuiv e 3. in v iew ot the pi essure change in the combustion chamber Thus, the engine output is too low and the knocking tendency may occui. w hich is not appropriate Also, in the case that the engine rotates at low speed, the tuel-an mixtui e w hose mixture ratio of fuel and air is moie than about 1 8 that is the tuel-an mixtuie hav ing a high fuel ratio may be fiequently taken into the comoustion chambei As a result, the fuel-air mixture is not fiequently fined and the w hole combustion time ot the fuel-air mixture becomes long considei ably Also, an incomplete combustion of the tuel-au mixture increases Accordingly , an exhaust matenai such as carbon oxide noxious to human body increases, thereby expediting an an en ironmental pollution Thus, the most reasonable ignition timing point is a point 1 1 at w hich the abo e-descnbed problems occurring at the ignition timing points T2 and F3 tan be pi ev ented The point T l is a point which is -35 ° on the crankshaft angle betoi e l euthing the TDC ot the piston

How ev ei. ev en in this case, a relativ e deci ease ol the engine et fitienty υctui s by the amount correspondence to an ai ea obtained by subtracting an aiea occupied bv the pressure curv e 1 from an area occupied by the pi essuie curv e 2 on the graph tompai ed ith the ease ot the ignition timing point T2 The w hole combustion time of the t uel-air mixtui e. in particulai. the pressure rise-up time becomes long

Fhei e are technical needs for maximizing the engine efficiency w hile solv ing t o the abov e-described defects which may occur owing to an earliei setting method ot the ignition timing point As an example, there is a need for realizing a technology of maximizing the engine efficiency by shortening the whole combustion time on the crankshaft angle of the fuel-air mixture, in particular, a pressure rise-up time, while hav ing no defects which may occur at the time of the earlier setting ot the ignition l s timing point

How ev er, the above-described conventional ignition plug has a simple conduction function in w hich the electrodes of the ignition plug aie conducted by the power source applied according to the ignition timing point set in the distributor to create an electric spark, thereby firing and continuously combusting the fuel-aπ

2 mixtuie in the combustion chamber, and has a functional limit

Disclosure of the Invention

To sol e the abov e problems, it is an ob|ect of the present inv ention to pro ide an ignition plug for shortening the whole combustion time ot a tuel-air mixture on a

25 crankshaft angle at maximum, m w hich part of the fuel-au mixtuie tompressed in an electric fiπng ty pe internal combustion engine is pi imaπly fired and combusted in adv antc at the time ol an ignition time of the engine and then an expanded explosiv e spark flame ot a small scale hav ing occurred thei efi om is discharged into a combustion chamber, to thereby fire a remaining fuel-air mixtui e in the combustion

"0 chamber taster and more rehabh. and combust it w ithin a much shorter time than the conventional art.

To accomplish the above object of the present invention, there is prov ided an ignition plug for use in an internal combustion engine ignition apparatus, the ignition plug comprising: a hollow tubular main cell 2 10: a pair of electrodes 230 comprising a 5 center electrode mounted in the hollow lower end of the main cel l and a ground electrode integrally formed in the lower end of the main cell, in correspondence to the center electrode and a pre-combustion chamber 250 formed in the low er end of the main cell, for accommodating part of a fuel-air mixture and combusting the same, in order to fire and combust a remaining portion of the fuel-air mixture compressed in a i t) combustion chamber within a shorter time, using an explosive spark flame of a small scale which occurs when the part of the compressed fuel-air mixture is fired and combusted in advance at the time of an ignition time of the engine.

Preferably, the pre-combustion chamber is formed of a pre-combustion chamber cell of a U-shaped vessel, having a fluid entrance and exit hole through which fluid

15 passes on the bottom thereof, surrounding the pair of electrodes and connected to the lower end of the main cell, and the pre-combustion chamber cell may be integrally formed with the main cell, or formed independently of the main cell so as to be assembled with or separated from the main cell.

The pre-combustion chamber cell is formed in a manner that it does not collide

20 with a up-and-down reciprocating piston during use in the engine, in which a length of a protrude from the lower end of the main cell is 5-7mm at maximum.

The fluid entrance and exit hole in the pre-combustion chamber cell is formed

_. of a circular shape of 3.4-4mm in diameter in the case that one of the combustion chamber in the internal combustion engine applied is 250-450cc in volume, and of

25 3.8-4.6mm in diameter in the case that one of the combustion chamber in the internal combustion engine applied is 500cc or more in volume, and the circumferential section of the fluid entrance and exit hole is rounded w ith a smooth curve so that an explosive spark flame of a small scale which occurs through a primary pre- combustion can be diffused into the combustion chamber quickly. Of course, the

30 fluid entrance and exit hole of the pre-combustion chamber may be formed of a ditf ei ent shape hav ing a different size

\t least one ground electrode is included, spaced by a predetermined gap horn the center electrode so as to be connected to the hollow internal surface ot the low ei end or the main cell W henev er necessary , a gap gauge is inserted into the fluid s entrance and exit hole from the outside of the pre-combustion ehambei. m order to adμist a gap between the ground electrodes and the centei electrode

The pre-combustion chamber accommodates part ot the compressed tuel-an mixtui e and fires and combusts the same, so that the expanded small scale explosiv e spai k flame combusts the whole of the remaining compressed fuel-air mixture within l o a shorter time and the whole combustion time of the fuel-air mixtui e is shortened 25- 26 at maximum on a crankshaft angle As a result, an ignition tune during a high speed rotation of the engine is set around -25° on the crankshatt angle, w hich is delay ed by about 25-26° on the crankshaft angle when compared w ith the conv entional art. to thereby maximize an efficiency of the engine during high speed

15 rotation

Also, the pre-combustion chamber accommodates part of the compressed fuel- air mixture and fires and combusts the same, so that the expanded small scale explosiv e spark flame combusts the whole of the remaining compressed fuel-an mixture withm a shorter time, with a result that an ignition time ot the engine during 0 low speed rotation is set 0° on the crankshaft angle, to thereby maximize an efficiency ot the engine during low speed rotation

Brief Description of the drawings rhe abov e object and other advantages of the present inv ention w ill become mo irre< apparent by describing the preferred embodiments thereof in more detail w ith l neterence to the accompan ing drawings in which

FlCi 1 is v iews for explaining an operating mechanism of an electric firing ty pe in ttec rnal combustion engine including a conventional ignition plug. FIG 2 is a sectional iew showing a conventional ignition plug. "A) FIG 3 is a graph showing a combustion-pressure curv e tυi explaining an efficiency ot an electric fii ~ g ty pe internal combustion engine

FIG 4A is a section , v iew show ing an ignition plug atcoi d g to a pi eteπ ed embodiment of the present inv ention.

FIG 4B is a ti ont v le sho ing an external shape ot FIG -A. and F IG 5 is a graph snow ing a combustion-pressure curv e foi explaining an efficiency of an electric fk g type internal combustion engine to w hich a preferi ed embodiment ot the present v ention is applied

Best Mode for Carry ing out the Invention l () Now. an ignition pi ag accoi ding to the prefei red embodiment of the present inv ention w ill be describee m detai l

An ignition plug 200 shown in FIGs 4A and 4B. includes a hollow main cell 210. a pair of electrodes 230 having a respectively different polaπty according to a power supply source, and an insulator 240 surroundingly coating a center electrode

15 232 of the pair of electrodes and mounted in the hollow of the mam cell 210 The insulator 240 surrounds an upper terminal 222 and a shaft rod 224 connected to the terminal 222 integrally A pair of ground electrodes 234. that is. a ground electrode 234 corresponding to the center electrode 232 is formed protrudingly at either side in the hollow internal surface of the lower end of the main cell 2 10 The ground 0 electrodes 234 and the center electrode 232 are disposed in a manner that each one surface opposes with a predetermined gap As described abov e since the ground electrodes 234 are formed in the hollow lower end ot the main cell 21 0. they are cooled quickly Thus, a conduction function with the center electrode 232 can be accomplished more effecti ely

2^ A pre-combustion cnamber 250 is prov ided in the lower end of the main cell

210 The pre-combustion chamber 250 has a protrude of a substantially L -shaped section and is a space formed in a pre-combustion chamber cell 252 A circular fluid entrance and exit hole 254 is formed in the substantial center of the bottom surface ot the pre-combustion chamber cell 252 so that fluid can pass The pre-combustion

30 chamber cell 252 is formed of a heat resistant steel material, and protruded by 5-7mm at maximum dow nw ards from the low er end of the main cel l 2 1 0 The dow nw ard protrude length of the pre-combustion chamber cell 252 is limited. As a result, the ignition plug 200 mounted in the internal combustion engine may not contact or collide w ith a piston w hich is positioned in the lower end of the ignition plug 200 and 5 reciprocates up and dow n.

Meanwhile, the pre-combustion chamber cell 252 may be integrally formed w ith the main cell 2 10 in which the circumferential portion of the lower end of the main cell 2 10 is extended, or formed independently of the main cell 210 so as to be assembled w ith or separated from the main cell 210. In the case that the pre- l o combustion chamber cell 252 is formed so as to be assembled w ith or separated from the main cell 2 10. tightness and assembly reliability should be enhanced considering a high pressure in the combustion chamber.

The fluid entrance and exit hole 254 in the pre-combustion chamber cell 252 is v aried in size according to a volume of each combustion chamber in the internal

15 combustion engine to which the ignition plug 200 is applied. The fluid entrance and exit hole 254 is formed of a circular shape of 3.4-4mm in diameter in the case that one of the combustion chamber is 250-450cc in volume, and of 3.8-4.6mm in diameter in the case that one of the combustion chamber is 450-500cc or so in volume. In addition, the circumferential section 256 of the fluid entrance and exit hole 254 in the 0 pre-combustion chamber cell is rounded with a predetermined radius R to form a smooth curv e, such that a fuel-air mixture or a spark flame can enter the pre- combustion chamber over the smooth curv ed surface easily . In particular, an explosive spark flame of a small scale which occurs in the pre-combustion chamber passes over the smooth curved surface of the fluid entrance and exit hole 254 and then

25 spreads w idely in the radial direction on the plane from the outer surface of the pre- combustion chamber cell 252. so as to be discharged into the combustion chamber. Accordingly, the fuel-air mixture in the combustion chamber is fired and combusted more quickly and reliably .

The ignition plug 200 according to the preferred embodiment of the present

30 inv ention having the above-described structure, accommodates in the pre-combustion ehambei 250 part ot the fuel-air mixtuie which is taken in the combustion thambei in an intake stroke in the electnc tiring ty pe internal combustion engine and then tompiessed in a compression stroke and simultaneously uses up bv tυi te of the piston 1 hen. the electrodes 230 are condutted to genet ate dn electnc spai k at an ignition time s ot a pow ei stroke The spark fires and combusts the tuel-an mixture accommodated in the pie-combustion chamber 250 II the fuel-an mixtuie in the pie-combustion chamber 250 is combusted, a small scale explosive spark flame is generated, which is filled in the pie-combustion chamber 250 The explosive spark flame in the pre- combustion chamber 250 rises up to a considerably high pressure ithin an extiemely

10 short time o ing to a rising piston Then, at the time when the pi essure ot the pie- combustion chamber 250 is highei than that of the lowei combustion ehambei in the ignition plug 200 is discharged the small scale explosiv e spark flame in the pie- eombustion chamber 250 toward the lower combustion chamber v ia the fluid entrance and exit hole 254 Here, since the circumferential section 256 ot the fluid entrance i ^ and exit hole 254 is rounded, the explosive spark flame spreads uniformly outw ards in radial direction and enters the combustion ehambei At this time, the remaining tuel- air mixture compressed in the combustion chamber is fired and combusted Also, the fuel-air mixture m the combustion chamber is fired by the small scale explosiv e spark flame discharged from the pre-combustion chamber 250 much faster and lehabh than 0 the conventional art. and combusted within a much shorter time than the conv entional art as well In particular, in the case that the engine rotates at high speed, the whole combustion time of the fuel-air mixture is shortened by about 25-26° on a ci ankshatt angle during high speed rotation of the engine, and by about 5 ^" on the ci ankshatt angle during low speed rotation, compared w ith the conv entional ai t. and the tuel-an s mixture is combusted close to a substantially perfect combustion The leduction in the whole combustion time ot the fuel-au mixtuie and improv ement of the fuel performance in accordance with the ignition plug 200 of the present inv ention influence greatly upon an efficiency ot the engine

Referring to FIG 5. the influences greatly upon an efficiency of the engine ot

30 the ignition plug 200 will be described in detail An ignition tuning point T4 i llusu aied in the graph ot FIG 5 i cpresents an ignition tuning point w inch is set din ing high speed rotation of the engine in which the ignition plug atcoi dmg to the pi esent inv ention is mounted A pressure curv e 4 icpresents a combustion ehambei pi essui e tnange w hith occui s on a crankshaft angle w hen an ignition tuning point din ing hign speed rotation is set to be T4 in the internal combustion engine in hith the ignition plug according to the pi esent invention is mounted

\s shown in FIG 5. if the w hole combustion time of the tuel-an mixture is shortened and the combustion performance is enhanced by the ignition plug 200 αctoiding to the preferred embodiment ot the present invention, an ignition timing

10 point of the engine considering high speed rotation can be changed and set to be a timing point T4 which is positioned at -25° x 10% before the top dead centei ( TDC ) which is delayed by the shortened time on the crankshaft angle from the tuning point 1 2 w hich is positioned at about -55 ^: before the conventional TDC Also, ev en in this case the tuel-air mixture is combusted close to a substantially perfect combustion i s Fhus. as illustrated in the pressure curve 4. the engine efficiency according to the present inv ention is nearly same as that of the engine during high speed rotation in w hich the conv entional ignition plug is mounted, whose ignition timing point is set T2 In addition, there is no knocking tendency phenomenon in the present invention

Also, even in the case that a lean mixture whose mixing ratio of fuel and an is 0 about 1 16- 1 '19 is used during high speed rotation of the engine, the present inv ention enhances a firing ability and a combustion performance, compared with the engine mounted w ith the conventional ignition plug Thus, the pi esent inv ention accomplishes a smooth firing and continuous combustion As a l esult. fuel can be sav ed greatlv Also, an exhaust gas harmful to the human body can πe leduted

2s ow g to enhancement ot the combustion pertoi mance

Mean hile, considering an engine during low speed rotation, the ignition plug accoi dmg to the piesent inv ention can make an ignition tuning point set to be at a position hich is positioned backw ard by about 5° on the crankshaft angle as much as a time corresponding to the shortened combustion time, that is. at 0 ' on the ciankshatt angle w hich is the TDC compared w ith the engine mounted w ith the conv entional ignition plug Accordingly , the fuel -air mιxu.. e taken into the combustion chamber at the intake stroke of the engine is

at the compression stroke at maximum so as to then be lgnified. As a result, the firing abihtv and the combustion performance ot the fuel-air mixtu. e are enhanced to thereby remarkably reduce firing and combustion loss and comp. _^ te combustion

Further, ev en in the case that the fuel-air mixture of a relativ e, y higher fuel ratio than the conventional art is taken in during the low speed rotation of the engine, a smooth firing and combustion can be accomplished, thereby maximizing an engine efficiency Also, an incomplete combustion portion of the fuel-air mixture can be reduced, to thereby lower an exhaust gas harmful to the human body such as carbon oxide, etc.

Industrial Applicability

The ignition plug according to the present invention hav ing me abov e structure includes a small pre-combustion chamber which can be integrated w ith or separated from the lower end of an existing ignition plug, and thus fires and combusts in advance a little amount of fuel-air mixture taken into the pre-combustion chamber during a compression stroke of the operating cy cle in the internal combustion engine, and discharges the explosiv e spark flame into the combustion chamber Accordingly . the whole fuel-air mixture compressed in the combustion ehambei is fired faster and more reliably, and the whole combustion time of the whole ruel-air mixture is remarkably shortened. As a result, it is possible to use a lean mixture w hich has av oided from being used due to an increase of the firing loss and incomplete combustion in the prior art. to thereby sav e fuel in use and enhance a combustion efficiency of the engine Also, the present inv ention accompl ishes a substantial perfect combustion to thereby prov ide a merit of reducing an amount of the exhaust gas harmful to the human body and remarkably reduce a complex a;r pollution Also, the engine efficiency can be maximized in either case of low speed rotation and high speed rotation. Also, the present invention provides a merit of enhancing a durability of the engine and extending a life cvcle Fhe present invention is not limited the abov e-described embodiment. It is apparent to a subiecl skilled in the art that there are many variations and modifications.

Claims

1 An ignition plug for use in an internal combustion engine ignition appaiatus the ignition plug comprising a hollow tubulai main cell ( 2 1 0 ) 5 a pan of electrodes ( 230 ) compnsing a center electrode mounted in the hollow lower end ot the main cell and a ground electrode integrally foi med in the lower end of the main cell, in coi respondence to the center electrode, and a pre-combustion chamber (250) formed in the lower end of the main cell, toi accommodating pan of a fuel-air mixture and combusting the same, in ordei to fin e 10 and combust a remaining portion of the fuel-air mixture compressed in a combustion chamber within a shorter time, using an explosive spark flame ot a small scale which occurs w hen the part of the compressed fuel-air mixture is fired and combusted in adv ance at the time of an ignition time of the engine

2 The ignition plug of claim 1. wherein said pre-combustion chamber is | s formed of a pre-combustion chamber cell of a L -shaped v essel, hav ing a fluid entrance and exit hole through which fluid passes on the bottom thei eot. surrounding the pair of electrodes and connected to the lowei end of the main cell

3 The ignition plug of claim 2. wherein said pre-combustion chamber cell is integrally formed with the main cell 0 4 The ignition plug of claim 2. wherein said pre-combustion chamber cell is assembled with or separated from the main cell

5 The ignition plug of claim 2. wherein said pie-combustion chamber cell is formed in a manner that a length of a protrude from the low er end of the ma cell is

5 -7mm at maximum s 6 The ignition plug of claim 2. whei em said fluid cnti ante and exit hole in the pre-combustion chamber cell is 3 44mm in diameter in the case that one of the combustion ehambei in the internal combustion engine applied is 250-45ϋcc in v olume

7 The ignition plug of claim 2. wherein said fluid entrance and exit hole in 30 the pre-combustion chamber cell is 3 8-4 6mm in diameter in the case that one ot the combustion chamber in the internal combustion engine applied is 500cc or more m olume.

8. The ignition plug of claim 2. wherein the circumferential section of said fluid entrance and exit hole is rounded with a smooth curve. 5 9. fhe ignition plug of claim 1 . wherein at least one ground electrode is incl uded, spaced by a predetermined gap from the center electrode so as to be connected to the hollow internal surface of the low er end of the main cell.

10. The ignition plug of claim 1. wherein said pre-combustion chamber accommodates part of the compressed fuel-air mixture and fires and combusts the l o same, so that the expanded small scale explosive spark flame combusts the w hole of the remaining compressed fuel-air mixture in the combustion chamber within a shorter time and the whole combustion time of the fuel-air mixture is shortened by 25-26° at maximum on a crankshaft angle.

1 1 . The ignition plug of claim 1. wherein said pre-combustion chamber 15 accommodates part of the compressed fuel-air mixture and fires and combusts the same, so that the expanded small scale explosive spark flame combusts the w hole of die remaining compressed fuel-air mixture in the combustion chamber within a shorter time, with a result that an ignition time of the engine during low speed rotation is set 0° on the crankshaft angle.