GB1567920A - Intake and exhaust manifold apparatus for internal conbustion engines - Google Patents

Description

(54) INTAKE AND EXHAUST MANIFOLD APPARATUS FOR INTERNAL COMBUSTION ENGINES (71) We, HONDA GIKEN KOGYO KABUSHIKI KAISHA, a Japanese body corporate of No. 27-8, 6-chome, Jingumae, Shibuya-ku, Tokyo, 150 Japan 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 followmg statement: This invention relates to intake and exhaust manifold apparatus for an internal combustion engine.

Conventional intake and exhaust manifold apparatus for internal combustion engines of the multiple cylinder type used mainly for automobiles is usually so arranged that the middle portions of the intake and exhaust passages are joined to an intake distribution chamber and an exhaust collection chamber respectively, these chambers forming a riser structure which is located substantially midway of the length of the apparatus. In the conventional arrangement this location of the riser structure obstructs access to some of the bolts for securing the manifold apparatus to the cylinder block, to the extent that assembly is difficult.

According to the present invention there is provided intake and exhaust manifold apparatus for an internal combustion engine, comprising an intake distribution chamber disposed substantially midway between the ends of the intake manifold, an exhaust collection chamber disposed under the said intake distribution chamber, the two said chambers together forming a riser structure for supporting a carburettor assembly in use, and flanges on the intake and exhaust manifolds for bolting the apparatus to an engine cylinder block, wherein the opposite sides of the said riser structure converge continuously from the part of the riser structure remote from the said flanges to the part thereof nearest said flanges, so as to facilitate access to bolts to located in the central region of the flanges.

An embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a plane view of the relevant parts of an engine incorporating the present invention; Figure 2 is a front view taken from the line 2-2 of Figure 1; and Figure 3 is a cross-section on the line 3-3 of Figure 1.

In the drawings, 1 shows a multi-cylinder engine having a single row of cylinders 2 each provided with an intake port 3 and an exhaust port 4 which open at one side of the engine, each exhaust port being joined to the exhaust port 4 of an adjacent cylinder.

An intake manifold 7 comprises a plurality of intake pipes 5 connecting the intake ports 3 to an intake distribution chamber 6 located substantially midway of the length of the intake manifold 7. An exhaust man ifold 10 comprises a plurality of exhaust pipes 8 connecting the exhaust ports 4 to an exhaust collection chamber 9, again centrally located. The said distribution chamber 6 is placed on top of the collection chamber 9 so as to form a riser structure 11, in which heat exchange takes place between the exhaust collection chamber 9 and the intake distribution chamber 6.

The two manifolds 7 and 10 are provided with respective flanges 12 and 13 attached to the engine by bolts 14. The bolts 14 are placed at convenient intervals which consist of, as illustrated in Figure 2 for instance, two bolts 14a, right and left, adjacent opposite sides of the riser structure, two bolts outwardly therefrom, and two bolts, upper and lower, at each further outer side.

In conventional systems, particularly the bolts 14a closer to the middle of the engine are not readily accessible as previously noted, posing a substantial disadvantage in assembly. However, in the present apparatus the said riser structure 11 is so constructed that its opposite side walls 20 are continually convergent towards the engine 1 at the same region as the central bolts 14a, all the way from the part 21 of the riser structure remote from the flanges 12 and 13 to the part 22 thereof nearest the said flanges.Thus the riser structure 11 is formed, as illustrated in Figure 1, in a substantially triangular shape as seen in plan view, narrowing gradually in width toward the engine 1; as a result the bolts 14a closer to the middle are accessible with a wrench or other tool "a" by inserting it as shown in Figure 1 from either side of the riser structure 11, thereby enabling a mechanical tightening operation to be performed.

On top of the intake distribution chamber 6 is provided a carburettor assembly (not shown).

In the engine illustrated, the combustion space 15 at the top of each cylinder 2 comprises a main combustion chamber 15a and a pre-combustion chamber 15b connected via a flame passage. The main combustion chamber 15a is supplied with a relatively large quantity of comparatively lean mixture and the pre-combustion chamber 15b is supplied with a relatively small quantity of comparatively rich mixture. Correspondingly, the carburettor assembly comprises a main carburettor and an auxiliary carburettor, and also each intake pipe 5 comprises a main intake pipe Sa connected to the main combustion chamber 15a and an auxiliary intake pipe Sb connected to the precombustion chamber 15b, the main carburettor being a dual bore type comprising a primary side and a secondary side.In this case, the relation between the intake passages in the riser structure 11 is such that, as can be seen from Figure 1 an auxiliary passage 17 connected to the auxiliary carburettor passage from the engine 1 side, a secondary main passage 18 connected to the secondary side of the main carburettor, and a primary main passage 19 connected to the primary side of the main carburettor, are placed in this order. Although not shown in the drawings, the riser structure includes a passage connected to the secondary main passage 18 placed relative to the auxiliary passage 17 in such a manner as not to be heated directly by the exhaust. By this arrangement, the engine output is improved and the heat receiving area of the auxiliary passage 17 is increased.

WHAT WE CLAIM IS: 1. Intake and exhaust manifold apparatus for an internal combustion engine, comprising an intake distribution chamber disposed substantially midway between the ends of the intake manifold, an exhaust collection chamber disposed under the said intake distribution chamber, the two said chambers together forming a riser structure for supporting a carburettor assembly in use, and flanges on the intake and exhaust manifolds for bolting the apparatus to an engine cylinder block, wherein the apposite sides of the said riser structure converge continuously from the part of the riser structure remote from the said flanges as to facilitate access to bolts to be located in the central region of the flanges.

2. Intake and exhaust manifold apparatus for an internal combustion engine, substantially as hereinbefore described with reference to the accompanying drawings.

3. An internal combustion engine having intake and exhaust manifold apparatus as claimed in claim 1 or 2.

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

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. are not readily accessible as previously noted, posing a substantial disadvantage in assembly. However, in the present apparatus the said riser structure 11 is so constructed that its opposite side walls 20 are continually convergent towards the engine 1 at the same region as the central bolts 14a, all the way from the part 21 of the riser structure remote from the flanges 12 and 13 to the part 22 thereof nearest the said flanges.Thus the riser structure 11 is formed, as illustrated in Figure 1, in a substantially triangular shape as seen in plan view, narrowing gradually in width toward the engine 1; as a result the bolts 14a closer to the middle are accessible with a wrench or other tool "a" by inserting it as shown in Figure 1 from either side of the riser structure 11, thereby enabling a mechanical tightening operation to be performed. On top of the intake distribution chamber 6 is provided a carburettor assembly (not shown). In the engine illustrated, the combustion space 15 at the top of each cylinder 2 comprises a main combustion chamber 15a and a pre-combustion chamber 15b connected via a flame passage. The main combustion chamber 15a is supplied with a relatively large quantity of comparatively lean mixture and the pre-combustion chamber 15b is supplied with a relatively small quantity of comparatively rich mixture. Correspondingly, the carburettor assembly comprises a main carburettor and an auxiliary carburettor, and also each intake pipe 5 comprises a main intake pipe Sa connected to the main combustion chamber 15a and an auxiliary intake pipe Sb connected to the precombustion chamber 15b, the main carburettor being a dual bore type comprising a primary side and a secondary side.In this case, the relation between the intake passages in the riser structure 11 is such that, as can be seen from Figure 1 an auxiliary passage 17 connected to the auxiliary carburettor passage from the engine 1 side, a secondary main passage 18 connected to the secondary side of the main carburettor, and a primary main passage 19 connected to the primary side of the main carburettor, are placed in this order. Although not shown in the drawings, the riser structure includes a passage connected to the secondary main passage 18 placed relative to the auxiliary passage 17 in such a manner as not to be heated directly by the exhaust. By this arrangement, the engine output is improved and the heat receiving area of the auxiliary passage 17 is increased. WHAT WE CLAIM IS:

1. Intake and exhaust manifold apparatus for an internal combustion engine, comprising an intake distribution chamber disposed substantially midway between the ends of the intake manifold, an exhaust collection chamber disposed under the said intake distribution chamber, the two said chambers together forming a riser structure for supporting a carburettor assembly in use, and flanges on the intake and exhaust manifolds for bolting the apparatus to an engine cylinder block, wherein the apposite sides of the said riser structure converge continuously from the part of the riser structure remote from the said flanges as to facilitate access to bolts to be located in the central region of the flanges.

2. Intake and exhaust manifold apparatus for an internal combustion engine, substantially as hereinbefore described with reference to the accompanying drawings.

3. An internal combustion engine having intake and exhaust manifold apparatus as claimed in claim 1 or 2.