GB1583532A

GB1583532A - Intake pipe manifold for inline internal combustion engines

Info

Publication number: GB1583532A
Application number: GB9809/78A
Authority: GB
Original assignee: Bayerische Motoren Werke AG
Current assignee: Bayerische Motoren Werke AG
Priority date: 1977-03-15
Filing date: 1978-03-13
Publication date: 1981-01-28
Also published as: IT7821073A0; SE7802907L; IT1093857B; SE439520B; JPS53113919A; JPS626106B2; FR2384120A1; FR2384120B1; BR7801563A

Description

(54) INTAKE PIPE MANIFOLD FOIR IN- LINE INTERNAL COMBUSTION ENGINES (roll) We, BAYERISCHE MOTOREN WERKE AKTIENGESELLSCHAFT, a German Body Corporate, of BMW-Haus, Petuelring 130, 8 München 40, German Federal Republic, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:: This invention relates to an intake pipe manifold for in-line internal combustion engines with from 4 to 6 cylinders with a collector housing from which individual intake pipes of substantially equal length emanate in respective opposed pairs substantially in a plane which have curved mutually overlapping intermediate sections and union ends connectable with induction ducts of the engine, with the union ends extending parallel to one another in the same direction and also substantially at right angles to the ends emanating from the collector housing, and with the collector housing arranged substantially centrally abreast of the union ends.

In a known intake pipe manifold of this construction (U.S. Patent 2,862,490) for a 6-cylinder engine with a triple carburettor mechanism, the intermediate sections of the individual intake pipes consist essentially of approximately parallel straight and oblique sections which are connected by elbows with small radii of curvature. In this assembly the flow of the gas and mixture charges suffer interference through turbulences in the individual intake pipes, so that no particularly favourable torque values and, hence, power output values can be achieved as a function of the engine revolutions.

Furthermore, the intake pipes are relatively short, which also leads to disadvantages in respect of the course of torque and power output.

The present invention aims to provide an intake pipe manifold whose individual intake pipes are of adequate length and which have relatively large radii of curvature without substantially increasing the space required by the intake pipe manifold.

This aim is achieved, in accordance with the invention, by providing an intake pipe manifold of the construction set fourth in the opening paragraph of the Specification in which the intermediate sections of the individual intake pipes are arranged in respective pairs situated, at least in part, in planes which intersect adjacent the union ends in imagainary axes parallel to the line of the union ends and diverge from said axes in a fan-shaped manner towards the collector housing.

By virtue of the construction of the intake pipe manifold in accordance with the invention, a good pulsational behaviour in the individual intake pipes and, hence, a good torque and power output development of the engine combined with a very small space requirement by the intake pipe maifold is achieved. The intake pipe manifold is suitable not only for Diesel or Otto injection-type internal combustion engines but also for carburettor-type Otto engines.

By means of a parallel displacement and/or pivoting of the intermediate sections with the collector housing about the imaginary intersecting axes and relative to the union ends having an adaptable course, it is possible to select an overall assembly which can be adapted in favourable manner to the respective space conditions.

Suitable embodiments of the invention are characterised in the dependent claims, with the features of claims 2 and 3 achieving a particularly compact and space-saving method of construction and with the features of claim 4 furnishing a design which is especially suitable for internal combustion engines arranged to have a lateral inclination, and with the vertical arrangement of the collector housing here resulting in a very small lateral space requirement by the intake pipe manifold.

Dependent claims 5, 6 and 7 characterise advantageous embodiments of the invention with a collector housing lying above the union ends, while dependent claims 8 to 12 and independent claim 16 contain, more especially, features for a design of the in take pipe manifold itself and of the casting core that is favourable in respect of machining and lends itself to straightforward casting during manufacture.

The particular construction of the intake pipe manifold for 4-cylinder in-line internal combustion engines in accordance with claims 13 to 15 achieves a good pulsational behaviour in the individual intake pipes and, hence, a good torque and power output development by the engine, because a direct transfer of pressure waves between mutually opposite individual intake pipes suffers interference by virtue of their mutually inclined arrangement.

The individual intake pipes in accordance with claim 14 are relatively long and have relatively large radii of curvature without substantially increasing the space requirements of the intake pipe manifold, thus giving a further improvement in the flow and pulsational behaviour inside the individual intake pipes. The features of claim 15 provide a transition from the individual intake pipes to their union ends which is favourable in respect of flow.

Embodiments of the invention are described in greater detail below, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a front elevation of an intake pipe manifold for a 6-cylinder in-line internal combustion engine; Figure 2 shows a side elevation of the intake pipe manifold of Figure 1; Figure 3 shows an oblique plan view of the intake pipe manifold of Figures 1 and 2 viewing in the direction of the arrow III in Figure 2; Figure 4 shows a front elevation of a different intake pipe manifold for a 6cylinder in-line internal combustion engine; Figure 5 shows a plan view of the intake pipe manifold of Figure 4; Figure 6 shows a side elevation of the intake pipe manifold of Figure 4; Figure 7 shows a section along line VII VII in Figure 4; Figure 8 shows a section along line VIII VIII in Figure 4;; Figure 9 shows a section along line IX IX in Figure 4; Figure 10 shows a section along X-X in Figure 4; Figure 11 shows a plan view on to an intake pipe manifold for a 4-cylinder in-line internal combustion machine in the direction of the arrow XI in Figure 12; and Figure 12 shows a side elevation of the intake pipe manifold of Figure 11.

Figures 1 to 3 show an intake pipe manifold 1 for a 6-cylinder in-line injection internal combustion engine (not shown) in the form of an Otto engine which comprises a collector housing 2 and six individual intake pipes 3, 4, 5, 6, 7 and 8. The individual intake pipes emanate in parallel and in mutually opposed pairs from the collector housing 2 in a plane 9 and are of equal length. They have curved, interengaging intermediate sections 10, 1lull, 12, 13, 14 and 15 and have union ends 16, 17, 18, 19, 20 and 21 which are connectable to induction ducts of a not-illustrated internal combustion engine and which extend approximately in the same direction in mutually parallel fashion and in a plane parallel to the axes 23, 24 and 25 of the ends of the individual intake pipes 3 to 8 emanating from the collector housing 2.

The internal cross-section of the individual intake pipes 3 to 8 decreases starting from the clollector housing 2 to the union ends 16 to 21. The collector housing 2 is arranged approximately mid-way abreast of the line of the union ends 16 to 21. Respective pairs of the curved intermediate sections 10 to 15 of the individual intake pipes 3 to 8 are at least partly arranged substantially in planes 26, 27 and 28 which intersect close to the union ends 16 to 21 approximately in axes 29, 30 and 3;1 imagined to be approximately parallel to the line of the union ends and, from there, diverge in fan-shaped manner towards the collector housing 2.

The ends of pairs of intake pipes 3 and 8, 4 and 7, and 5 and 6 emanating from the collector housing 2 are spaced from the group of imaginary axes 29 to 31 by different respective distances. The two individual intake pipes of the pair 3 and 8 emanating from the collector housing 2 farthest from the group of imaginary axes 29 to 31 are connected to the two middle union ends 18 and 19 respectively. Those two individual intake piper of the pair 3 and 8 emanating from the collector housing 2 closest to the group of imaginary axes 29 to 31 are connected to the two outer union ends 1-6 to 21 respectively. The two individual intake pipes of the pair 4 and 7 emanating from the collector housing 2 between the pairs of intake pipes 3 and 5, and 6 and 8 are connected to the union ends 17 and 20 respectively. Those curved intermediate sections 11 to 14 of the individual intake pipes 4 to 7 are curved in approximately S-shaped fashion, first, towards the union ends 16 to 21, then towards each other and, finally, towards their respective union ends 17 to 20.

The plane 9 substantially containing the ends of the individual intake pipes 3 and 8 emanating from the collector housing 2 is arranged approximately at right angles to the plane 28 containing the curved intermediate sections 10 and 15 of the two individual intake pipes 3 and 6 emanating from the collector housing 2 closest to the imagin ary axles 29 to 31. This first-named plane 9 makes -an - acute angle with a flange plane 32 of flanges 33 of the union ends 16 to 21 which is open towards the union ends 16 to 21 and towards the collector housing 2. The union ends 16 to 21 therefore display matching curvatures from their imagin at"" axes 29 to 31 towards their flanges 33.

The collector housing 2 has a greatly curved and end-face wall 34 which lies approximately in a plane parallel to the ends of the. individual intake pipes 3 to 8 emanating from it and, at right angles to the same, two mutually parallel side-walls 35. At the upper end the tnd-face wall 34 changes over into an upper wall 36. The collector housing -2, further, has a rear wall 37 whose upper portion is arranged to be substantially parallel to the end-wall 34. In the upper portion of the rear wall 37 a port 35 is provided to which a not illustrated air supply line can be connected. The union ends 16 to 21 have moulded-on fastening locations 39 for injection valves.

By means of this construction of the collector housing 2 and the following-on individual intake pipes 3 to 8 with their union ends 16 to 21, it is possible to accommodate long individual intake pipes of relatively large radii of curvature and equal length in a confined space. The intake pipe manifold 2 can be produced as a single-piece casting.

For this reason it is shaped in such a way that it can be removed from the mould relatively readily and simply and also free of undercuts. The individual intake pipes 3 to 8 have common wall sections in interengaging regions and the two individual intake pipes 5 and 6 terminating in the middle union ends 18 and 19 also have wall sections in common with the collector housing 2.

This feature not only achieves an enhanced rigidity but also improved mouldability and also a substantial avoiding of an accumulation of material.

Furthermore, the intake pipe manifold 2 is shaped such that one mould (in addition to the cores required) is sufficient for casting, with the mould having only two mould parts and one sliding member. The individual intake pipes 3 to 8 are connected to each other partly by walls 40 in the region of mould joint surfaces. A high degree of rigidity of the intake pipe manifold is achieved and excessive trimming is avoided by means of these walls.

Figures 4 to 10 show a modified embodi ment of the above-described intake pipe manifold. This intake pipe manifold 101 comprises a collector housing 102 and six individual intake pipes 103, 104, 105, 106, 107 and 108. The individual pipes emanate from the collector housing 1012 parallel and in mutually opposed pairs in a plane 109 and are of equal length.They have curved overlapping intermediate sections 110, lli, 112, 113, 114 and 115 and have tiflion ends 116, 117, 118, 119, 130 and 121 connectable to induction ducts of a not illustrated internal combustion-engine, which union ends extend approximately in the same direction parallel to each other andapproximately in a plane 122 approximately at right angles to the ends emanating from the collector housing 102. The internal cross-section of the individual intake pipes 102 to 108 is circular and decreases towards the union ends 116 to l2l7starting from the collector housing 102. The collector housing is arranged approximately abreast of and above the union ends 116 to 121.The curved intermediate sections 110 to 115 of the individual intake pipes 103 to 108 extend such that there is oorrespondence between the sequence of the points of emanation of the individual intake pipes 103 to 108 from the collector housing 102 -commencing with the individual intake pipes 105 and 106 emanating from the collector housing 102 on the side of the union ends 116 to 121 and whose union ends 118 and 119 lie immediately adjoining in the middle of the line of the union ends 1116 to 121-and the sequence of their union ends 118, 117, 116 and 119, 120 121 respectively commencing from the middle of the line of union ends.This means that the two middle union ends 118 and 119 are assigned to the two individual intake pipes 103 to 108 emanating from the collector housing 102 on the side remote from the union ends 116 to 121 assigned to them. The two further individual intake pipes 104 and 107 emanating between the named individual intake pipes 103 and 105 and 106 nected to the middle union ends 1!18 and 119 first of all curve away from the union ends 116 to 121 and then towards these.

A first part 123, 124, 125, 126, 127 and 128 repectively of the intermediate sections 110 to 115 of the individual intake pipes 103 to 108 of each pair lies approximately in a plane 129 which with the plane 122 of the union ends 116 to 121 makes an angle that is open towards the latter. The plans 129 intersect in one or more axes 129' imagined to be parallel to the line of the union ends 116 to 121. The angle a is constructed to increase with an increasing distance of the points of emanating of the pairs of individual intake pipes 105, 106; 1-04, 107; and 103, 108 respectively from the collector housing 102 plane lying on the side of the union ends 116 to 121.A respective second part 130, 131, 132, 133, 134 and 135 of the intermediate sections 110 to 115 of the individual intake pipes 103 to 108 lies substantially in a plane 36 which, with the plane 122 of the union ends 116 to 121, makes an angle ss that is open in a direction away from the collector housing. The angle ss is constructed to increase with an increasing distance of the union ends 118, 119, 117, 120 and 116, 121 respectively from the centre of the line of the union ends, so that the plane 136 containing the second parts 130, 135 of the curved intermediate sections 116, 121 of the two individual intake pipes 103 and 108 with their outer union ends is approximately parallel to the central long plane 137 of the collector housing 102.

The collector housing 102 has an upper surface 138 that is curved gently and lies approximately in a plane parallel to the ends of the individual intake pipes 103 to 108 enmanating from the collector housing 102 and, at right angles to the same, has two mutually parallel side-walls 139 and 140.

At the end of the collector housing lying towards the union ends 116 to 121, the upper side 138 is drawn downwards in a curve 141 and changes over into a low end-well 142 which, by way of a further curve 143, changes over into an inclined bottom 144.

The inclined bottom 144 faces the union ends 116 to 121 and lies approximately parallel to the plane 129 containing the first parts 15 and 16 of the intermediate sections 112 and 113 of the individual intake pipes 105 and 106 connected to the middle union ends 118 and 119. At its end facing away from the union ends 116 to 121, the collector housing 102 has a wall 145 which is arranged approximately parallel to the first parts 123 and 128 of the intermediate sections 110 and 115 of the individual intake pipes 103 and 108 changing over into the outer union ends 116 and 121. An opening 146 to which an air supply line (not shown) can be connected is provided in the wall 145.Underneath the opening 146 a bore 148, terminating in a recess 149 at the lowest point of the collector housing 102, is provided in an extension 147 of the collector housing ]02 for a not-illustrated supplementary air union. A bore 151 for a not-illustrated starter nozzle is arranged in the bottom 150 of the recess 149.

The union ends 116 to 121 are provided with flanges 152 which, over the region of their half positioned towards the collector housing 102, are joined to one another. In the wall of each union end 116 to 121 facing towards the inclined bottom 144 there are provided a respective drilled passage 153, inclined in the direction of the flange 152, and a contact making surface 154 in which respectively a not illustrated injection nozzle can be inserted.

By means of this construction of the collector housing 102 and the following-on individual intake pipes 103 to 108, with their union ends 116 to 121, individual, long intake pipes of equal length with relatively large radii of curvature can be accommodated within a confined space.

The intake pipe manifold 101 can be fabricated as a single-piece casting. For this reason it is shaped in such a way that it can be removed from the mould relatively easily and also free from undercuts.

The individual intake pipes 103 to 108 have common wall sections 155, 156 over the interengaging regions, and the two individual intake pipes 105 and 106 terminating in the middle union ends 118 and 119 also have common wall sections 157 with the collector housing 102. As a result, improved moulding properties as well as a greater rigidity is achieved.

Furthermore, the intake pipe manifold 102 is shaped in such a way that one mould having only two mould parts and two sliding members is sufficient for the casting. The individual intake pipes 103 to 108 are connected to one another within range of mould joint surfaces partly by walls 158, 159, and 160. Respectively one of these walls 158 extends between one side-wall 139, 140 of the collector housing 102 and the first part 125 and 126 respectively of the curved intermediate sections 112 and 113 of the individual intake pipes 105 and 106 respectively emanating from the union ends 116 to 121 closest to the collector housing 102. The walls 158 lies approximately parallel to the inclined bottom 144 of the collector housing 102.Further walls 159, 160, which are continuations of the walls 158, extend between the individual intake pipes 103 to 105 and 106 to 108 in correspondence with their respectively greater angle a relative to the union ends 116 and 121 as far as a rib 161, whose main parts 162 connect the individual intake pipes 103 to 108 over the region of the change-over of their curved intermediate sections 110 to 115 into the union ends 116 to 121. The rib 161 lies in a mould joint surface and extends in a plane parallel to the inclined bottom 144 of the collector housing 102.

Within the region of the collector housing 102, the rib 161 is offset in parallel fashion in the direction of the opening 146 of the collector housing 102, with transition sections 163 connecting the offset part 164 of the rib 161 with the two main parts 162.

Further walls 165 following on the collector housing 102 lie abreast of the individual intake pipes 103 to 108 facing the first-named walls 158 to 160 and the rib 161, within the region of their points of emanating from the collector housing 102, and extend as far as the change-over from the first parts 123 to 128 of the curved intermediate sections 110 to 115 into the second parts 130 to 135 of the curved intermediate sections 110 to 115. The walls 165 and the first-named walls 158 merge into one another, and on either side of the collector housing 102, form a recess 166 capable of being moulded without undercut portions. Downstream from the rib 161, the individual intake pipes 103 to 108'are not connected to each other by wall parts lying in between. Only the flanges 152 of their union ends 116 to 121 are joined to one another.Since the individual intake pipes 103 to 108 lie partly eccentrically to the mould joint surface within the region of their emergence from the collector housing 102, they are provided with projections 167 which extend tangentially relative to the otherwise circular external contours approximately in the direction of removal from the mould as far as the wall 165 arranged in one mould joint. surface. The mould joint surface also extends eccentrically within the region of the union ends H6 to 121, so that the union ends 116 to 121, too, are provided with projections 168 extending tangentially to the otherwise circular outer contours apprdximately in the direction of reinoving from the mould as far as the mould joint surface.On the side of the union ends 116 to 121 facing the inclined bottom 144 of the collector housing 102, a respective longi túdinal bead 169 is provided to extend approximately parallel to the direction of removing from the mould and which contains the drilled passage for accommodating an injection nozzle. The contact-making surfaces 154 in the walls or longitudinal beads 169 of the union ends can be milled in a single workstage.

The tangential projections 167, 168 make possible a simple moulding of the intake pipe manifold without loose parts. The walls 158 to 160 and 165 arranged between the collector housing 102 and the individual intake pipes 105 and 106 and between the individual intake pipes respectively, and also the rib, avoid or facilitate the trimming work and impart an enhanced rigidity to the intake pipe manifold assembly 101. The longitudinal beads 169 extending approximately as far as the change-over of the union ends 116 to 121 into the curved intermediate sections 110 to 115 also serve to avoid undercut portions.

The casting core 170 illustrated in dotdash and shaded dot-dash fashion in Figure 7 for casting the intake pipe manifold 101 consists of three core sections l71, 172, 173 which are connected with each other interengagingly and in laminar fashion over the region of the collector housing 102. Each of these core sections 171, 172, 173 consists of a core part for the collector- housing and two core parts for respectively two mutually oppositely emanating individual intake pipes 105 and 106, 104 and. 107 and 103 and 108 respectively all emanating from the collector housing 102. As a result of this relatively simply and cheaply.In addition, any casting skin or burr formation occurs at locations in the collector housing at wiiich dividing up, the core 170 can be fabricated the flow through the casting skin or the burrs is not influenced adversely The illustrated and above-described intake pipe manifolds can be modified in a simple manner, more especially for in-line internal combustion engines with 5 and 4 cylinders, by omitting one or two outer individual intake pipes.Here, both the course of the individual intake pipes and also the position of the collector housing relative to the union ends can be varied considerably to match the respective spatial requirerhCnts, within the scope of the invention, by a parallel displacement and/or pivoting about the named intersection axs of tiie'interm.ediate section planes.All that is necessary for carburettor engines is to adapt the collector housing to the carburettor unions in the usual way. Within the scope of the invention, the ends of the individual intake pipes emanating from the collector housing can, alternatively, lie in a triangular arrangement in, 'Which the ends of the middle individual 'intake pipes are spaced away further from the imaginary axes than is illustrated, instead of lying in a plane. As a result, where required an even smaller constructional height of the collector housing and, hence, of the over all intake pipe manifold is realised.

Figures 11 and 12 show an intake pipe manifold 101 for a not illustrated Cylinder in-line internal combustion engine in the form of an Otto engine which consists substantially of a collector housing 202- and individual intake pipes 203, 204, 2Q5 and 206. The individual intake pipes 203 and 206 emerge from the collector housing 202 mutually obliquely and in mutual opposition in pairs and are of approximately equal length.They interengage and have union ends 207, 208, 209 and 210 connectable to induction ducts of the not illustrated internal combustion engine by means 6f flanges, which union ends extend approximately parallel in the same direction and parallel to a vertical central long plane 211 of the collector housing 202. Imaginary extensions 212, 213, 214 and 215 of the individual intake pipes 203 to 206 connected obliquely to side-walls 216 and 217 of the collector housing, which are drawn in dot-dash fashion in the drawing, inter-sect mutually in respective pairs within range of respective adjoining end-face walls 218 'and 219 of 'the -collector lion'sing 202.

A port 22!1 is provided in the lower wall 220 of the collector housing, to which port an air supply (not shown) can be connected.

The individual intake pipes 202 and 206 emerging from the collector housing 202 closest to the union ends 207 to 210 extend away from the central long plane 211 of the collector housing 202 and the union ends 207 to 210 in a continuous arc 222 and back towards both and respectively change over into the union ends 207 and 210 via an approximately straight intermediate piece and a reverse-shape arc 224.

The individual intake pipes 204 and 205 emerging from the collector housing remote from the union ends 207 to 210 extend away from the central long plane 211 of the collector housing 202 in a continuous arc 225 and back towards the same as well as simultaneously towards the union ends, and, after an aproximately straight intermediate piece 226, change over into their union ends 208 and 209 by way of a reverseshape arc 227. All individual intake pipes 203 to 206 are curved to sag downwards gently, with the curvature of the individual intake pipes 203 and 206 emerging from the collector housing 202 closest to the union ends 207 to 21'0 being stronger than that of the other two individual intake pipes 204 and 205.

The union ends 207 to 210 are respectively provided with a flange 228 and 229, and for stiffening purposes are connected to one another by webs 230. The individual intake pipes 203 and 204 and 205 and 206 respectively are connected with each other by walls 231 lying in mould joint surfaces in order to give a shape facilitating casting and for stiffening.

The fact that the respective individual intake pipes 203 and 206 and 204 and 205 emerging from the collector housing 202 in mutually opposed manner are not connected to the collector housing 202 in pairs coaxially but at an angle to one another avoids an adverse mutual influencing of vibrations by a direct transfer of pressure waves between the individual intake pipes 203 to 206 and achieve a better filling of an internal combustion machine provided with the intake pipe manifold 202. The individual intake pipes 203 to 206 of equal length with their approximately equal and relatively large, flow-assisting radii of curvature make an additional contribution to good pulsational behaviour, so that good power output and torque values are achieved with the intake pipe manifold 202.

WHAT WE CLAIM IS:- 1. An intake pipe manifold for in-line internal combustion engines with from 4 to 6 cylinders with a collector housing from which individual intake pipes of substantially equal length emanate in respective opposed pairs substantially in a plane which have curved mutually overlapping intermediate sections and union ends connectable with induction ducts of the engine, with the union ends extending parallel to one another in the same direction and also substantially at right angles to the ends emanating from the collector housing, and with the collector housing arranged centrally abreast of the union ends, in which the intermediate sections of the individual intake pipes are arranged in respective pairs situated, at least in part, in planes which intersect adjacent the union ends in imaginary axes parallel to the line of the union ends and diverge from said axes in a fan-shaped manner towards the collector housing.

2. An intake pipe manifold according to claim 1, in which the ends of the individual intake pipes emanating from the collector housing are spaced at varying distances from the imaginary axes, wilth the two individual intake pipes emanating from the collector housing spaced farthest away from the imaginary axes being connected to the two middle union ends, the two individual intake pipes emanating from the collector housing lying closest to the imaginary axes being connected to the two outer union ends and, where applicable, the two individual intake pipes emanating from the collector housing between the named individual intake pipes being connected to the union ends lying between the middle and the outer union ends, and in which at least the curved intermediate sections of the individual intake pipes emanating from the collector housing farthest away from the imaginary axes are curved in substantially S-shaped manner first towards the union ends, then towards each other and, finally, towards their union ends.

3. An intake pipe manifold according to claim 2, in which the plane substantially containing the curved intermediate sections of the two individual intake pipes emanating from the collector housing closest to the imaginary axes is arranged substantially at right angles to the plane containing the ends of the individual intake pipes emanating from the collector housing.

4. An intake pipe manifold according to claim 3, in which the plane which contains the ends of the individual intake pipes emanating from the collector housing make an acute angle with a flange plane of flanges of the union ends.

5. An intake pipe manifold according to any one of claims 1-3 in the form of a onepart casting, in which a respective first part of the intermediate sections of the individual intake pipes of each pair lies substantially in a plane which, with the plane of the union ends, makes an angle open in the direction of the union ends and one end of the collector housing and increasing with an increasing distance of the points of emanation of the pairs of the individual

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. closest to the union ends 207 to 210 extend away from the central long plane 211 of the collector housing 202 and the union ends 207 to 210 in a continuous arc 222 and back towards both and respectively change over into the union ends 207 and 210 via an approximately straight intermediate piece and a reverse-shape arc 224. The individual intake pipes 204 and 205 emerging from the collector housing remote from the union ends 207 to 210 extend away from the central long plane 211 of the collector housing 202 in a continuous arc 225 and back towards the same as well as simultaneously towards the union ends, and, after an aproximately straight intermediate piece 226, change over into their union ends 208 and 209 by way of a reverseshape arc 227. All individual intake pipes 203 to 206 are curved to sag downwards gently, with the curvature of the individual intake pipes 203 and 206 emerging from the collector housing 202 closest to the union ends 207 to 21'0 being stronger than that of the other two individual intake pipes 204 and 205. The union ends 207 to 210 are respectively provided with a flange 228 and 229, and for stiffening purposes are connected to one another by webs 230. The individual intake pipes 203 and 204 and 205 and 206 respectively are connected with each other by walls 231 lying in mould joint surfaces in order to give a shape facilitating casting and for stiffening. The fact that the respective individual intake pipes 203 and 206 and 204 and 205 emerging from the collector housing 202 in mutually opposed manner are not connected to the collector housing 202 in pairs coaxially but at an angle to one another avoids an adverse mutual influencing of vibrations by a direct transfer of pressure waves between the individual intake pipes 203 to 206 and achieve a better filling of an internal combustion machine provided with the intake pipe manifold 202. The individual intake pipes 203 to 206 of equal length with their approximately equal and relatively large, flow-assisting radii of curvature make an additional contribution to good pulsational behaviour, so that good power output and torque values are achieved with the intake pipe manifold 202. WHAT WE CLAIM IS:-

1. An intake pipe manifold for in-line internal combustion engines with from 4 to 6 cylinders with a collector housing from which individual intake pipes of substantially equal length emanate in respective opposed pairs substantially in a plane which have curved mutually overlapping intermediate sections and union ends connectable with induction ducts of the engine, with the union ends extending parallel to one another in the same direction and also substantially at right angles to the ends emanating from the collector housing, and with the collector housing arranged centrally abreast of the union ends, in which the intermediate sections of the individual intake pipes are arranged in respective pairs situated, at least in part, in planes which intersect adjacent the union ends in imaginary axes parallel to the line of the union ends and diverge from said axes in a fan-shaped manner towards the collector housing.

intake pipes from that end of the collector housing and in that a respective second part of the intermediate sections of the individual intake pipes lies substantially in a plane which, with the plane of the union ends, makes an angle open in a direction away from the collector housing and increasing with an increasing distance of the union ends of the pairs of the individual intake pipes from the mid-point between the two middle union ends.

6. An intake pipe manifold according to claim 5, in which the collector housing has an inclined bottom facing towards the union ends which lies substantially parallel to the plane containing the first part of the intermediate sections of the individual intake pipes connected to the middle union ends.

7. An intake pipe manifold according to claim 5 or claim 6, in which the individual intake pipes are at least partly connected to each other by walls which are situated with mould joint surfaces.

8. An intake pipe manifold according to any one of claims 5 to 7, in which the individual intake pipes have substantially circular cross-section internally and have projections externally over regions in which they lie eccentrically with respect to mould joint surfaces, which projections extend tangentially to the otherwise circular outer contours substantially in the direction of removing from the mould up to the mould joint surface or up to a wall arranged there.

9. An intake pipe manifold according to claim 7, in which the curved intermediate sections of those individual intake pipes which emanate from the said one end of the collector housing touch the collector housing with their central region and with the same have a respective common wall section, in which a respective wall lying in a mould joint plane extends substanially parallel to the inclined bottom of the collector housing between the collector housing and the first parts of these intermediate sections, and in which the sides of the individual intake pipes facing these walls lie in a mould joint surface and with these walls form one respective substantially wedge-shaped recess.

10. An intake pipe manifold according to claim 9, in which a rib which transversely connects the individual intake pipes with each other lies substantially in one plane with the inclined bottom of the collector housing and, in common with the walls lying parallel to the inclined bottom of the collector housing, lies in a mould joint surface, and in which the rib at an end-face port of the collector housing extends out of its principal plane on both sides of the port substantially to the centre of the port.

11. An intake pipe manifold according to claim 9 or claim 10, in which the individual intake pipes are connected by walls lying in mould joint surfaces in the direction of the collector housing from the rib onwards and are separated from one another--except for their mutually con nected flanges in the direction of the union ends.

12. An intake pipe manifold according to any one of claims 5 to 12, in which the individual intake pipes have a respective -longitudinal bead in the region of their union ends on the external sides facing the collector housing, which bead extends respectively substantially from the end-face provided with a flange as far as the merging into the curved intermediate sections and which is pierced by a drilled passage that is oblique to the union end for accom modating an injection nozzle.

13. An intake pipe manifold according to claim 1 or claim 2, more especially for 4-cylinder internal combustion engines, in which the ends of respectively two indi vidual intake pipes emanating mutually oppositely from the collector housing are connected in mutually inclined manner to the collector housing, with their imaginary prolongations extending into the collector housing intersecting each other.

14. An intake pipe manifold according to claim 13, with the two individual intake pipes emanating from the collector housing closest to the union ends respectively cross ing over the adjoining individual intake pipes and turning over to the outer union ends of the line, in which the individual intake pipes emanating from the collector housing closest to the union ends extend respectively, by way of a continuous arc and, optionally, further sections, away from a central long plane of the collector housing arranged parallel to and across the line of the union ends, and from the union ends, and back again towards these two, while individual intake pipes emanating from the collector housing remote from the union ends extend away from the central long plane by way of a continuous arc and, optionally, further sections, and back to wards the same, and also extend towards the union ends.

15. An intake pipe manifold according to claim 14, in which all individual intake pipes are curved downwards over a sub stantial portion of their length, and in which adjacent the union ends, there is arranged a respective reverse-shaped arc whose radius of curvature substantially matches that of the continuous arcs.

16. A casting core for producing an intake pipe manifold as claimed in any one of the preceding claims, in which the core parts for two individual intake pipes emanating mutually oppositively from the collector housing form a respective singlepart core, section together with the core part for the portion of the collector housing lying in between, and in which the core sections are connected to one another over the region of their core parts for the collector housing so as to be positionally secured.

17. An intake pipe manifold substantially as described herein with reference to Figures 1-3, Figures 410 or Figures 11 and 12 of the accompanying drawings.

18. An engine having an intake pipe manifold as claimed in any one of claims 1-15 or claim 17.