CA1064345A - Dual spark plug ignition internal combustion engine having improved cylinder head - Google Patents
Dual spark plug ignition internal combustion engine having improved cylinder headInfo
- Publication number
- CA1064345A CA1064345A CA273,829A CA273829A CA1064345A CA 1064345 A CA1064345 A CA 1064345A CA 273829 A CA273829 A CA 273829A CA 1064345 A CA1064345 A CA 1064345A
- Authority
- CA
- Canada
- Prior art keywords
- cylinder head
- cylinder
- intake
- intake valve
- combustion chamber
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Abstract
ABSTRACT OF THE DISCLOSURE
An intake port and an intake valve seat of an internal combustion engine are arranged such that sufficient swirl turbulence of the air-fuel mixture inducted through the intake port is produced in the combustion chamber. This turburence improves the com-bustion carried out in the combustion chamber even through the combustion chamber is supplied with a considerably large amount of recirculated exhaust gases.
An intake port and an intake valve seat of an internal combustion engine are arranged such that sufficient swirl turbulence of the air-fuel mixture inducted through the intake port is produced in the combustion chamber. This turburence improves the com-bustion carried out in the combustion chamber even through the combustion chamber is supplied with a considerably large amount of recirculated exhaust gases.
Description
~0~;4345 BA~ ,ROIl~D OF TIIE I~TVE~TION
Field Or the In~etltion This invention relates to an internal combustion engine of the type wherein two spark plugs are disposed in each combustion chamber to reliably ignite a charge mixed w~th the exhaust gases fed into the combustion chamber, and more particularly to a cylinder head con-figuration of the engine.
Descri~tion of the Pri_r Art In order to supprcss the gencration of nitrogen oxides (NOx) during combustion of the air-fuel mixture in the combustion chambers, it has already been proposed that two spark plugs are disposed spaced apart in the - combustion chamber to ignite and combust the air-fuel ; 15 mixture mixed hith a considerably large amount of the exhaust gases fed into the combustion chamber. In general, as the amount of the exhaust gas feed increases, the combustion time is prolonged and accordingly the engine running becomes unstable. Ilowever, by the effect of the dual spark plug ignition, the combustion time of the mixture in the combustion chamber is shortened, . .
CAUSillg stable and smooth running of the engine.
Nevertheless it i5 no~ required to further improve and stabilize the combustion in the combustion chamber in order to improve fuel consumption characteristics .
~' `' ~
--.,2~--. ...... .
.
.: : . .: .
~o~434~
and engine output power performance characteristics in addition to reducing noxious gas emission.
SU~AII~ 0~ TIIE INV~NTION
It is the main ol-ject of the preAent invention to provide an improved internal combustion engine arranged such that an air-fuel mixture mixed with a considerably large amount of exhaust gases is ignited ~.
wlth two spark plugs disposed in each combustion chamber, in which the combustion of the air-fuel mixture in the combustion chan-ber is improved to obtain further smooth and stable engine running.
: ,Another object of the present invention is to provide an internal combustion engine having an im-. proved cylinder head configuration by which air and fuel inducted into the combustion chamber are homogene-ously mixed and the vapourization of the fuel is pro-moted in order to improve the combustion of the air-fuel mixture in the combustion chamber.
~ A further object of the present invention is to provide an internal combustion ensine havins an im-proved cy].inder head configuration by which sufficient swirl turbulence of the air-fuel mixture is produced in the combustion chamber without considerable flow resistance of the air-fuel mixture passing through intake port formed in the cylinder head.
,y _ 10~4345 A still further object of the present invention to provide an internal combustion engine having an improved cylin-der head configuration in which an intake port is arranged to prevent the air-fuel mixture inducted into the combustion chamber from being directed immediately downward in the direction of the center axis of the cylinder.
In accordance with the above objects, the invention broadly claimed herein is an internal combustion engine which includes a cylinder block having a cylinder in which a piston 0 reciprocally moves, the engine further comprising a cylinder head secured at its bottom flat surface to the cylinder block and formed with a concavity which closes one end of the cylinder, a combustion chamber being defined between the cavity and the crown of the piston. Two spark plugs are disposed through the -~
cylinder head such that the midpoints defined by their electrodes project into and lie in the combustion chamber, the spark plugs being located generally opposite to each other with respect to the center axis of the cylinder bore. Intake and exhaust valve .
heads are movably disposed through the concavity of the cylinder head such that their centers are spaced apart from each other in the direction of the longitudinal axis of the cylinder heacl.
An intake valve seat is embedded in the concavity of the cylinder head, which seat has a bottom annular surface exposed to the combustion chamber, the intake valve head being seatable in the intake valve seat. An intake port is formed in the cylinder head, being connectable at one end to the combustion chamber through the intake valve seat and opening at the other end to one side surface of the cylinder head forming an opening at one side surface of the cylinder head, the minimum distance between the center of the opening formed at the side surface of the cylinder head and an imaginary line passing through the center of the plane defined by the bottom annular f - 3 -.
surface of the intake valve seat being within the range of 0.65 to 0.95 times the minimum diameter of a throat portion having the minimum cross-sectional area in the intake port and the inner surface of the intake valve seat, as viewed from the direction of the longitudinal axis of the cylinder head, the imaginary line extending parallel with the bottom flat surface of the cylinder head. Means are provided for feeding a portion of the exhaust gases into the combustion chamber through the intake port.
Other object, features and advantages of the engine in accordance with the present invention will become more apparent from the following description of a preferred embodi-ment thereof, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
. . .
:
Fig. 1 is a plan view of a portion of the cylinder head of an internal combustion engine embodying the present invention, showing a concavity formed in the cylinder head; and ., Fig. 2 is a longitudinal cross-sectional view of the engine of Fig. 1, showing the cylinder head cross-section taken along the line I-I of Fig. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to Figs. 1 and 2 of the drawings, a preferred embodiment of an internal combustion engine in accordance with the present invention is designated generally by the reference numeral 10 and shown ~
,~ / , :~ /
.~ / .
~; /
:1 -i ~ ~ - ~ 4 -~, --- ,... . . -.- ~ - - : ~ . . .
~064;~45 including an engine proper (no numeral). The engine proper ha~ a cylinder block 12 in which a cylinder 14 or cylinders are, as customary, formed. A piston 15 i9, as usual, reciprocally movable in the cylinder 14.
Secured to the upper surface of the cylinder block 12 is a cylinder head 16 which i4 formed with a hemi_ - spherical concavity 18 defining therein an upper part of combustion chamber 20. The surface of the concavity 18 close~ the one or upper end of the cylindcr bore.
A~ best seen in Fig. 1, intake and exhau~t valve heads 22 and 24 are respectively seatably dispo~ed on intake and exhaust valve seats (not shown in Fig. 1) secured or embedded in the hemispherical surface of the con-cavity 18. The intake and exhaust valve head~ 22 and 24 are located such that their center~ Ci and Ce are on opposite ~ides of a longitudinal vertical plane M
which is parallel with the longitudinal axis (not shown) of the cylinder head 16 and which is parallel with and pa~ses through the center axis 0 of the cylinder 14 or 20' the center axeY of the cylinderY. Furthermoro, the - centerR C and C of the intake and exhaust va]ve heads 1 e _ 22 nnd 24 are located spaced apart from each other in the direction of the lon~itudinal axis of the cylinder head 16.
The reference numerals 26 and 28 represent re-spectively generallv cylindrical intake and exhaust . .
~ 5 ~
.'.' ' ' ; .
. . ' .
: ~ .
port~ formed in the cylinder head 16. The intake port 27 communicates, at its one end, through an intake valve seat 30 (show}l in-Fig. 2) with the combustion chamber 20 and opens, at the other end, to one side surface 16a of the cylinder head 16. The exhaust port 28~communicates, at its one end, through the exhaust valve seat with thc combustion chamber 20 and opens, at the other endt to the opposite ~ide surface 16b of the cylinder head 16~ This arrangement of the intake and exhaust ports 26 and 28 is referred to as a cross-flow induction-exhaust arrangement. In the cross-flow induction-exhaust arrangement of Fig. 1, ~hile the intake and exhaust ports 26 and 28 have been ,~
shown such that their center axeq (not shown) are parallel with each other and intersect the longitudinal axis of the cylinder head 16 at right angles, as viewed from the direction of cylinder center axis 0, it will be understood that the intake and exhaust ports 26 and ~ 20 are othcrwise arrangable and therefore are not limited to the arrangcment of Fig. 1 ; Two spark plugs 32a and 32b are disposed through the cylinder head 16 and projected into the combustion ; chamber 20 from the surface of concavity 18. The spark plugs 32a and 32b are located such that the midpoints (not identified) of spark gaps defined by their elec-trodes (no numerals) projected into the combustion _ 6 --"
.
chamber lies generall,y symmetrically or opposite with respect to the center axis 0 of the cylinder 14 and spaced apart from the cylinder center axis 0.
As clearly shown in Fig. 2 in which the intake valve 22 is not shown but only the longitudinal center axis thereof indicated by a bro~en line Ai, the intake valve 22 is located such that its center axis Ai inter-' sects the center axis 0 of the cylinder at an angle Q
of 22.5 +6 ~ as viewed from the direction of the plane ~1 or of the longitudinal axis of the cylinder head 16.
Additionally, the intake valve head 22 is so located that its center axis Ai passes through the center Cv of an imaginary plane P defined and enclosed by the annular bottom surface 30a of the intake valvo seat 30~ the annular bottom surface 30a being exposed to the combustion chamber 20. The intake port 26 is as shown~ formed such that its center axis Lc has a curved portion (no numeral) which is formed with a - radius R of curvatureO The curved portion of the intake port center axis Lc smoothly joins at its one end to the intaXe valve center axis Ai as clearly shown in ~ig. 20 The other end of the curved portion of the intake port center axis L joins to a generally straight portion tno numeral) which generally cor-.
,, 25 responds to a tangent line of the curvature of the :
~ 7 ~
.
~ .
- . . .
- . : ' . ~ . ,, curved portionO It is to be noted that the generally straight portion of the intake port center axis Lc is generally parallel to the bottom ~urface B of the cylinder head 16, and passes through the center Cp of the opening 26a of the intake port 26 which opening 26a is formed at the side surface 16a of the cylinder head 16. The cylinder head 16 is secured at the bottom ~urface B thereof to the cylinder block as seen in ~ig. 2.
The generally straight portion of the intake port center axi~ Lc may be replaced with a gentle curve : having a larger radius of curvature. In this case, the locations of the intake valve seat 30 and the ~:~ intake port 22 is in the relationship that the hoisht 11 of the ccnter Cp of the opening 22a of the intake port 22 from the center Cp of the imaginary plane P
defined by the annular bottom surface 30a of the intake valve seat 30 is within the range from o.65 to 0.95 times the minimum diameter D of a throat portion T of tho intake port 26. The throat portion T corresponds to a portion having the minimum cross-sectional area in the intake port 26 and the inner surface of the intake valve seat 30. The height H corresponds to the minimum distance between the center C~ and an imaginary : 25 line Li which pasYes through the center Cv and is . , ~ . . .
1()6434S
parallel to the cylinder head bottom flat surface B;
the plane defined by the bottom flat surface B being perpendicular or horizontal with respect to the longi- -tudinal vqrtical plane M, as shown in Fig. 2.
ProJected into the intake port 26 is a cylindrical -valve guide 34 within which the ~tem of the intake valve head ~2 is slidably supported though not shown.
The reference numeral 36 indicates a device or mean~
for feeding or recirculating a portion of the exhaust gases of the engine into the combustion chamber 20 through the intake port 26. In this case, the device 36 is arranged to supply the exhaust $ases in the maximum amount ranging from 25 to 40% by volume of the intake air supplied to the combustion chamber 200 The device 36 is known in the art as disclosed, for example, in U0 S. Pat. No. 3,756,Z10, issued Sept. 4, 1973 to Kuehl. ^
With the arrangement hereinbefore de~cribed~ the air-fuel mixture inducted through the intake port 26 is ~upplied into the combustion chamber 20 generating the swirl turbulence moving in the direction indicated by arrows a a~ shown in Fig. 1. Thus, the air-fuel ; mixture rotating in the direction of the arrows a is not immediately directed downward along the cylinder center axis 0 toward the piston~crown, and the swirl .
i g ~
' - ~' .
,. . . . . :
- : .. , .: .:
turbulence is maintained for a relatively long period of time, because the center axis L of the intake port 26 is generally parallel with the cylinder head bottom surface B and accordingly a do~ward force is not applied to tlle air-fuel mixture pa~sing tllrough the intake ~ort 22. Consequently, the spiraling air-fuel mixture in the combustion chamber 20 descends relatively slowly toward the piston crown causing sufficient mixing of fuel and air. As a result, the mixture of the fuel and air is homogenized promoting the vapour-ization of the fuel.
The above-mentioned range of height H of the intake port center Cp from the intake valve seat center Cv has experimentally determined by the following reasonsO ~Then the hei~ht H is higher than 0.95 times the diameter D, the angle at which the air-fuel mixture is directed into the combustion chamber 20 is too large and accordingly a downward force is applied to the air-fuel mixture directed into the combustion chamber 20. As a result, the piston 15 reaches the bottom dead center without the rotation of the air-fuel mixture by the swirl turbulence being sufficiently accomplished.
Conversely, the height H is lower than o.65 times the diametcr D, the curvature of the curved portion of the intake port cAuses an increase in the flow resistance of the air-fuel mixture passing through the intake port 26.
''' ' .
,, -- 1 0 _ ' ' - .
, .
: .
.
.' ~ . . .
10t;434S
Experiments revealed that when the above-mentioned heisht H was set at about o.80 times the diameter D, gcneration of the swirl turbulence wa9 remarkable and the flow resistance of the air-fuel mixture was low~
achieving optimwn combustion carried out in the com-bustion,chamber.
It will be ullderstood that~ by setting the above-mentioned height H within the range^according to the present invention, fast combustion duc to the ignition Wit}l two spark plugs is further promoted and the stability of the combustion is further improved.
.: .
:. Therefore~ the engine according to the present invention : can stably run achieving a noticeable decrease in the emission level of ~TOx, improving the fuel consumption --cha~acteristics and the engine output powe- performance.
'~ ~ ' ' ' .
.
_ 11 --., .
- ~ ' ' ' : ,
Field Or the In~etltion This invention relates to an internal combustion engine of the type wherein two spark plugs are disposed in each combustion chamber to reliably ignite a charge mixed w~th the exhaust gases fed into the combustion chamber, and more particularly to a cylinder head con-figuration of the engine.
Descri~tion of the Pri_r Art In order to supprcss the gencration of nitrogen oxides (NOx) during combustion of the air-fuel mixture in the combustion chambers, it has already been proposed that two spark plugs are disposed spaced apart in the - combustion chamber to ignite and combust the air-fuel ; 15 mixture mixed hith a considerably large amount of the exhaust gases fed into the combustion chamber. In general, as the amount of the exhaust gas feed increases, the combustion time is prolonged and accordingly the engine running becomes unstable. Ilowever, by the effect of the dual spark plug ignition, the combustion time of the mixture in the combustion chamber is shortened, . .
CAUSillg stable and smooth running of the engine.
Nevertheless it i5 no~ required to further improve and stabilize the combustion in the combustion chamber in order to improve fuel consumption characteristics .
~' `' ~
--.,2~--. ...... .
.
.: : . .: .
~o~434~
and engine output power performance characteristics in addition to reducing noxious gas emission.
SU~AII~ 0~ TIIE INV~NTION
It is the main ol-ject of the preAent invention to provide an improved internal combustion engine arranged such that an air-fuel mixture mixed with a considerably large amount of exhaust gases is ignited ~.
wlth two spark plugs disposed in each combustion chamber, in which the combustion of the air-fuel mixture in the combustion chan-ber is improved to obtain further smooth and stable engine running.
: ,Another object of the present invention is to provide an internal combustion engine having an im-. proved cylinder head configuration by which air and fuel inducted into the combustion chamber are homogene-ously mixed and the vapourization of the fuel is pro-moted in order to improve the combustion of the air-fuel mixture in the combustion chamber.
~ A further object of the present invention is to provide an internal combustion ensine havins an im-proved cy].inder head configuration by which sufficient swirl turbulence of the air-fuel mixture is produced in the combustion chamber without considerable flow resistance of the air-fuel mixture passing through intake port formed in the cylinder head.
,y _ 10~4345 A still further object of the present invention to provide an internal combustion engine having an improved cylin-der head configuration in which an intake port is arranged to prevent the air-fuel mixture inducted into the combustion chamber from being directed immediately downward in the direction of the center axis of the cylinder.
In accordance with the above objects, the invention broadly claimed herein is an internal combustion engine which includes a cylinder block having a cylinder in which a piston 0 reciprocally moves, the engine further comprising a cylinder head secured at its bottom flat surface to the cylinder block and formed with a concavity which closes one end of the cylinder, a combustion chamber being defined between the cavity and the crown of the piston. Two spark plugs are disposed through the -~
cylinder head such that the midpoints defined by their electrodes project into and lie in the combustion chamber, the spark plugs being located generally opposite to each other with respect to the center axis of the cylinder bore. Intake and exhaust valve .
heads are movably disposed through the concavity of the cylinder head such that their centers are spaced apart from each other in the direction of the longitudinal axis of the cylinder heacl.
An intake valve seat is embedded in the concavity of the cylinder head, which seat has a bottom annular surface exposed to the combustion chamber, the intake valve head being seatable in the intake valve seat. An intake port is formed in the cylinder head, being connectable at one end to the combustion chamber through the intake valve seat and opening at the other end to one side surface of the cylinder head forming an opening at one side surface of the cylinder head, the minimum distance between the center of the opening formed at the side surface of the cylinder head and an imaginary line passing through the center of the plane defined by the bottom annular f - 3 -.
surface of the intake valve seat being within the range of 0.65 to 0.95 times the minimum diameter of a throat portion having the minimum cross-sectional area in the intake port and the inner surface of the intake valve seat, as viewed from the direction of the longitudinal axis of the cylinder head, the imaginary line extending parallel with the bottom flat surface of the cylinder head. Means are provided for feeding a portion of the exhaust gases into the combustion chamber through the intake port.
Other object, features and advantages of the engine in accordance with the present invention will become more apparent from the following description of a preferred embodi-ment thereof, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
. . .
:
Fig. 1 is a plan view of a portion of the cylinder head of an internal combustion engine embodying the present invention, showing a concavity formed in the cylinder head; and ., Fig. 2 is a longitudinal cross-sectional view of the engine of Fig. 1, showing the cylinder head cross-section taken along the line I-I of Fig. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to Figs. 1 and 2 of the drawings, a preferred embodiment of an internal combustion engine in accordance with the present invention is designated generally by the reference numeral 10 and shown ~
,~ / , :~ /
.~ / .
~; /
:1 -i ~ ~ - ~ 4 -~, --- ,... . . -.- ~ - - : ~ . . .
~064;~45 including an engine proper (no numeral). The engine proper ha~ a cylinder block 12 in which a cylinder 14 or cylinders are, as customary, formed. A piston 15 i9, as usual, reciprocally movable in the cylinder 14.
Secured to the upper surface of the cylinder block 12 is a cylinder head 16 which i4 formed with a hemi_ - spherical concavity 18 defining therein an upper part of combustion chamber 20. The surface of the concavity 18 close~ the one or upper end of the cylindcr bore.
A~ best seen in Fig. 1, intake and exhau~t valve heads 22 and 24 are respectively seatably dispo~ed on intake and exhaust valve seats (not shown in Fig. 1) secured or embedded in the hemispherical surface of the con-cavity 18. The intake and exhaust valve head~ 22 and 24 are located such that their center~ Ci and Ce are on opposite ~ides of a longitudinal vertical plane M
which is parallel with the longitudinal axis (not shown) of the cylinder head 16 and which is parallel with and pa~ses through the center axis 0 of the cylinder 14 or 20' the center axeY of the cylinderY. Furthermoro, the - centerR C and C of the intake and exhaust va]ve heads 1 e _ 22 nnd 24 are located spaced apart from each other in the direction of the lon~itudinal axis of the cylinder head 16.
The reference numerals 26 and 28 represent re-spectively generallv cylindrical intake and exhaust . .
~ 5 ~
.'.' ' ' ; .
. . ' .
: ~ .
port~ formed in the cylinder head 16. The intake port 27 communicates, at its one end, through an intake valve seat 30 (show}l in-Fig. 2) with the combustion chamber 20 and opens, at the other end, to one side surface 16a of the cylinder head 16. The exhaust port 28~communicates, at its one end, through the exhaust valve seat with thc combustion chamber 20 and opens, at the other endt to the opposite ~ide surface 16b of the cylinder head 16~ This arrangement of the intake and exhaust ports 26 and 28 is referred to as a cross-flow induction-exhaust arrangement. In the cross-flow induction-exhaust arrangement of Fig. 1, ~hile the intake and exhaust ports 26 and 28 have been ,~
shown such that their center axeq (not shown) are parallel with each other and intersect the longitudinal axis of the cylinder head 16 at right angles, as viewed from the direction of cylinder center axis 0, it will be understood that the intake and exhaust ports 26 and ~ 20 are othcrwise arrangable and therefore are not limited to the arrangcment of Fig. 1 ; Two spark plugs 32a and 32b are disposed through the cylinder head 16 and projected into the combustion ; chamber 20 from the surface of concavity 18. The spark plugs 32a and 32b are located such that the midpoints (not identified) of spark gaps defined by their elec-trodes (no numerals) projected into the combustion _ 6 --"
.
chamber lies generall,y symmetrically or opposite with respect to the center axis 0 of the cylinder 14 and spaced apart from the cylinder center axis 0.
As clearly shown in Fig. 2 in which the intake valve 22 is not shown but only the longitudinal center axis thereof indicated by a bro~en line Ai, the intake valve 22 is located such that its center axis Ai inter-' sects the center axis 0 of the cylinder at an angle Q
of 22.5 +6 ~ as viewed from the direction of the plane ~1 or of the longitudinal axis of the cylinder head 16.
Additionally, the intake valve head 22 is so located that its center axis Ai passes through the center Cv of an imaginary plane P defined and enclosed by the annular bottom surface 30a of the intake valvo seat 30~ the annular bottom surface 30a being exposed to the combustion chamber 20. The intake port 26 is as shown~ formed such that its center axis Lc has a curved portion (no numeral) which is formed with a - radius R of curvatureO The curved portion of the intake port center axis Lc smoothly joins at its one end to the intaXe valve center axis Ai as clearly shown in ~ig. 20 The other end of the curved portion of the intake port center axis L joins to a generally straight portion tno numeral) which generally cor-.
,, 25 responds to a tangent line of the curvature of the :
~ 7 ~
.
~ .
- . . .
- . : ' . ~ . ,, curved portionO It is to be noted that the generally straight portion of the intake port center axis Lc is generally parallel to the bottom ~urface B of the cylinder head 16, and passes through the center Cp of the opening 26a of the intake port 26 which opening 26a is formed at the side surface 16a of the cylinder head 16. The cylinder head 16 is secured at the bottom ~urface B thereof to the cylinder block as seen in ~ig. 2.
The generally straight portion of the intake port center axi~ Lc may be replaced with a gentle curve : having a larger radius of curvature. In this case, the locations of the intake valve seat 30 and the ~:~ intake port 22 is in the relationship that the hoisht 11 of the ccnter Cp of the opening 22a of the intake port 22 from the center Cp of the imaginary plane P
defined by the annular bottom surface 30a of the intake valve seat 30 is within the range from o.65 to 0.95 times the minimum diameter D of a throat portion T of tho intake port 26. The throat portion T corresponds to a portion having the minimum cross-sectional area in the intake port 26 and the inner surface of the intake valve seat 30. The height H corresponds to the minimum distance between the center C~ and an imaginary : 25 line Li which pasYes through the center Cv and is . , ~ . . .
1()6434S
parallel to the cylinder head bottom flat surface B;
the plane defined by the bottom flat surface B being perpendicular or horizontal with respect to the longi- -tudinal vqrtical plane M, as shown in Fig. 2.
ProJected into the intake port 26 is a cylindrical -valve guide 34 within which the ~tem of the intake valve head ~2 is slidably supported though not shown.
The reference numeral 36 indicates a device or mean~
for feeding or recirculating a portion of the exhaust gases of the engine into the combustion chamber 20 through the intake port 26. In this case, the device 36 is arranged to supply the exhaust $ases in the maximum amount ranging from 25 to 40% by volume of the intake air supplied to the combustion chamber 200 The device 36 is known in the art as disclosed, for example, in U0 S. Pat. No. 3,756,Z10, issued Sept. 4, 1973 to Kuehl. ^
With the arrangement hereinbefore de~cribed~ the air-fuel mixture inducted through the intake port 26 is ~upplied into the combustion chamber 20 generating the swirl turbulence moving in the direction indicated by arrows a a~ shown in Fig. 1. Thus, the air-fuel ; mixture rotating in the direction of the arrows a is not immediately directed downward along the cylinder center axis 0 toward the piston~crown, and the swirl .
i g ~
' - ~' .
,. . . . . :
- : .. , .: .:
turbulence is maintained for a relatively long period of time, because the center axis L of the intake port 26 is generally parallel with the cylinder head bottom surface B and accordingly a do~ward force is not applied to tlle air-fuel mixture pa~sing tllrough the intake ~ort 22. Consequently, the spiraling air-fuel mixture in the combustion chamber 20 descends relatively slowly toward the piston crown causing sufficient mixing of fuel and air. As a result, the mixture of the fuel and air is homogenized promoting the vapour-ization of the fuel.
The above-mentioned range of height H of the intake port center Cp from the intake valve seat center Cv has experimentally determined by the following reasonsO ~Then the hei~ht H is higher than 0.95 times the diameter D, the angle at which the air-fuel mixture is directed into the combustion chamber 20 is too large and accordingly a downward force is applied to the air-fuel mixture directed into the combustion chamber 20. As a result, the piston 15 reaches the bottom dead center without the rotation of the air-fuel mixture by the swirl turbulence being sufficiently accomplished.
Conversely, the height H is lower than o.65 times the diametcr D, the curvature of the curved portion of the intake port cAuses an increase in the flow resistance of the air-fuel mixture passing through the intake port 26.
''' ' .
,, -- 1 0 _ ' ' - .
, .
: .
.
.' ~ . . .
10t;434S
Experiments revealed that when the above-mentioned heisht H was set at about o.80 times the diameter D, gcneration of the swirl turbulence wa9 remarkable and the flow resistance of the air-fuel mixture was low~
achieving optimwn combustion carried out in the com-bustion,chamber.
It will be ullderstood that~ by setting the above-mentioned height H within the range^according to the present invention, fast combustion duc to the ignition Wit}l two spark plugs is further promoted and the stability of the combustion is further improved.
.: .
:. Therefore~ the engine according to the present invention : can stably run achieving a noticeable decrease in the emission level of ~TOx, improving the fuel consumption --cha~acteristics and the engine output powe- performance.
'~ ~ ' ' ' .
.
_ 11 --., .
- ~ ' ' ' : ,
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An internal combustion engine including a cylinder block having therein a cylinder in which a piston is disposed reciprocally movable, comprising:
a cylinder head secured at its bottom flat surface to the cylinder block and formed with a con-cavity, the surface of the concavity closing one end of the cylinder and defining a combustion chamber between the concavity surface and the crown of the piston;
two spark plugs disposed through said cylinder head such that the midpoints of the spark gaps defined by the electrodes of said two spark plugs project into and lie in the combustion chamber, and are located generally opposite to each other with respect to the center axis of the cylinder bore;
intake and exhaust valve heads movably dis-posed through the concavity surface of said cylinder head such that the centers thereof are located spaced apart from each other in the direction of the longi-tudinal axis of cylinder head;
an intake valve seat embedded in the concavity surface of said cylinder head, said intake valve seat having a bottom annular surface which is exposed to the combustion chamber, said intake valve head being seatable on said intake valve seat;
an intake port formed in said cylinder head, said intake port being connectable at its one end to the combustion chamber through said intake valve seat, and opening at its other end to one side surface of said cylinder head forming an opening at the one side surface of the cylinder head, the minimum distance between the center of the opening formed at the side surface of the cylinder head and an imaginary line passing through the center of the plane defined by the bottom annular surface of said intake valve seat being within the range from 0.65 to 0.95 times the minimum diameter of a throat portion having the minimum cross-sectional area in said intake port and the inner surface of said intake valve seat, as viewed from the direction of the longitudinal axis of the cylinder head, the imaginary line extending parallel with the bottom flat surface of said cylinder head; and means for feeding a portion of the exhaust gases into the combustion chamber through said intake port.
a cylinder head secured at its bottom flat surface to the cylinder block and formed with a con-cavity, the surface of the concavity closing one end of the cylinder and defining a combustion chamber between the concavity surface and the crown of the piston;
two spark plugs disposed through said cylinder head such that the midpoints of the spark gaps defined by the electrodes of said two spark plugs project into and lie in the combustion chamber, and are located generally opposite to each other with respect to the center axis of the cylinder bore;
intake and exhaust valve heads movably dis-posed through the concavity surface of said cylinder head such that the centers thereof are located spaced apart from each other in the direction of the longi-tudinal axis of cylinder head;
an intake valve seat embedded in the concavity surface of said cylinder head, said intake valve seat having a bottom annular surface which is exposed to the combustion chamber, said intake valve head being seatable on said intake valve seat;
an intake port formed in said cylinder head, said intake port being connectable at its one end to the combustion chamber through said intake valve seat, and opening at its other end to one side surface of said cylinder head forming an opening at the one side surface of the cylinder head, the minimum distance between the center of the opening formed at the side surface of the cylinder head and an imaginary line passing through the center of the plane defined by the bottom annular surface of said intake valve seat being within the range from 0.65 to 0.95 times the minimum diameter of a throat portion having the minimum cross-sectional area in said intake port and the inner surface of said intake valve seat, as viewed from the direction of the longitudinal axis of the cylinder head, the imaginary line extending parallel with the bottom flat surface of said cylinder head; and means for feeding a portion of the exhaust gases into the combustion chamber through said intake port.
2. An internal combustion engine as claimed in Claim 1, in which said two spark plugs are disposed such that the midpoints of the spark gaps thereof lie opposite with respect to a longitudinal vertical plane which is parallel with the longitudinal axis of said cylinder head and passing through the center axis of the cylinder, in which said intake and exhaust valve heads are disposed such that the centers thereof lie opposite to each other with respect to the longitudinal vertical plane.
3. An internal combustion engine as claimed in Claim 2, in which said intake valve head is located such that the center axis thereof intersects the center axis of the cylinder at an angle ranging from 16.5 to 28.5 degrees, as viewed from the direction of the longitudinal axis of the cylinder head, the center axis of the intake valve corresponding to that of a valve stem integral with said intake valve head.
4. An internal combustion engine as claimed in Claim 1, in which said means for supplying a portion of the exhaust gases is arranged to supply the com-bustion chamber with the exhaust gases in the maximum amount ranging from 25 to 40% by volume of the intake air supplied to the combustion chamber.
5. An internal combustion engine as claimed in Claim 4, in which the minimum distance between the center of the opening formed at the side surface of the cyliner head and the imaginary line parallel to the cylinder head bottom flat surface and passing through the center of the plane defined by the bottom annular surface of said intake valve seat is about 0.80 times the minimum diameter of the throat portion.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP51026319A JPS5810563B2 (en) | 1976-03-11 | 1976-03-11 | Cylinder head of two-point ignition engine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1064345A true CA1064345A (en) | 1979-10-16 |
Family
ID=12190059
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA273,829A Expired CA1064345A (en) | 1976-03-11 | 1977-03-10 | Dual spark plug ignition internal combustion engine having improved cylinder head |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5810563B2 (en) |
| CA (1) | CA1064345A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56127846U (en) * | 1980-02-29 | 1981-09-29 |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2522921A (en) * | 1946-12-31 | 1950-09-19 | Jean A H Barkeij | Combustion chamber for internalcombustion engines |
| JPS4840606A (en) * | 1971-09-30 | 1973-06-14 |
-
1976
- 1976-03-11 JP JP51026319A patent/JPS5810563B2/en not_active Expired
-
1977
- 1977-03-10 CA CA273,829A patent/CA1064345A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS52109020A (en) | 1977-09-12 |
| JPS5810563B2 (en) | 1983-02-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPS5949407B2 (en) | Combustion chamber of internal combustion engine | |
| US4071001A (en) | Stratified combustion engine with prechamber | |
| US4038952A (en) | Internal combustion engine | |
| US4119065A (en) | Internal combustion engine having an auxiliary combustion chamber and a method of control of combustion in said internal combustion engine | |
| JPS5936089B2 (en) | Internal combustion engine with auxiliary combustion chamber | |
| US4294207A (en) | Externally ignited, four-cycle, piston-type internal combustion engine | |
| US3963003A (en) | Combustion chamber arrangements for I.C. engines | |
| JPH10317975A (en) | Direct cylinder injection spark ignition engine | |
| US4344407A (en) | Cylinder head, ports, and piston configuration | |
| JPS5851130B2 (en) | Combustion chamber structure of internal combustion engine | |
| CA1064345A (en) | Dual spark plug ignition internal combustion engine having improved cylinder head | |
| US4116181A (en) | Dual spark plug ignition internal combustion engine | |
| JPS5851131B2 (en) | Combustion chamber structure of internal combustion engine | |
| US4459804A (en) | Multiple spark ignition internal combustion engine with exhaust gas recirculation | |
| JPS6217090B2 (en) | ||
| CN212563446U (en) | Medium-heavy ignition engine combustion chamber | |
| JPS5855327B2 (en) | Combustion chamber of internal combustion engine with auxiliary combustion chamber | |
| US4048973A (en) | Internal combustion engine provided with pre-combustion chamber | |
| JPS598644B2 (en) | Secondary combustion chamber of internal combustion engine | |
| JPS6236131B2 (en) | ||
| JPH10141065A (en) | Direct in-cylinder injection type spark ignition engine | |
| CN117231381A (en) | Engine and vehicle | |
| US4114569A (en) | Internal combustion engine with an auxiliary combustion chamber | |
| JPS5833213Y2 (en) | Improved structure of pre-chamber in internal combustion engine | |
| CA1071956A (en) | Dual spark plug ignition internal combustion engine |