GB2296530A

GB2296530A - I.c.engine air intake manifold

Info

Publication number: GB2296530A
Application number: GB9525881A
Authority: GB
Inventors: Peter Citron; Horst Engelking
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 1994-12-23
Filing date: 1995-12-19
Publication date: 1996-07-03
Anticipated expiration: 2015-12-19
Also published as: GB2296530B; FR2728628B1; DE19546643A1; FR2728628A1; DE19546643B4; GB9525881D0

Abstract

To achieve intake passages of equal length from the manifold plenum chamber with cylinder head ports 2, 3 of unequal length opening to one side of the head, the short and long manifold passages K and L leading via common passages 9 to the ports are of compensating lengths. The short passages K are controlled by valves 11 which are arranged in two spaced parallel rows 13 and 14. The ports 2, 3 may lead to the cylinders of an in-line engine or respective banks of a V-engine. The manifold may be formed in two parts with a joining plane T. <IMAGE>

Description

DESCRIPTION AIR INTAKE SYSTEM FOR A MULTI-CYLINDER RECIPROCATING PISTON INTERNAL COMBUSTION ENGINE The present invention relates to an air intake system for a multi-cylinder reciprocating-piston internal combustion engine.

EP-03 82 596 B1, discloses an air intake system in which each cylinder within an inlet manifold casing is assigned two intake pipes of different lengths.

These two pipes are in each case branches of a Yshaped branch pipe, the outlet of which is fed as a single pipe along a lateral longitudinal wall out of the inlet manifold casing to the corresponding cylinder. Upstream of the branch in the Y, the respective shorter intake pipe is made switchable by means of a butterfly to improve the torque curve.

Such an arrangement cannot however be employed with two-row V-type internal combustion engines since, for these, the outlet branch pipe would in each case have to be divided again and the length from there to the cylinders of the two rows would be unequal.

Moreover, this prior art cannot be employed in the case of in-line internal combustion engine with, for example, two inlet valves per cylinder, the inletvalve axes of which are not arranged in a common plane running parallel to the longitudinal direction of the internal combustion engine. A valve arrangement of this kind with a twist relative to the cylinder longitudinal axis, to achieve an inlet swirl, is known, for example, from DE-17 51 401.

The aim of the present invention is to provide an air intake system of the generic type which delivers as high a torque as possible over the entire speed range of the internal combustion engine in the case of reciprocating-piston internal combustion engines with inlet-valve axes which are not arranged in a common plane running parallel to the longitudinal direction of the internal combustion engine.

According to the present invention there is provided an air intake system for a multi-cylinder reciprocating-piston internal combustion engine, comprising an inlet manifold casing with intake pipes of different lengths, of which at least half can be shut off by means of valve devices, in which arrangement at least two intake pipes in each case are connected to a common branch pipe, which is provided with an outlet connected, in use, to at least one inlet port formed in a cylinder head of the internal combustion engine, all the outlets being arranged essentially along a single lateral longitudinal wall of the inlet manifold casing, the valve devices being arranged along at least two mutually spaced and essentially parallel rows running in the said longitudinal direction to close sections of the intake pipes, as desired.

If, in an air intake system of the generic type, those sections of the intake pipes that can be closed by means of the valve devices, are arranged in two mutually spaced rows running essentially parallel in the longitudinal direction, it is thereby possible, while forming identical intake-line lengths, to supply fresh air to inlet ports in the cylinder head which are controlled by inlet valves that are not arranged in a plane running parallel to the longitudinal direction of the internal combustion engine. This arrangement can be used with advantage in the case of in-line internal combustion engines which have, for example, two inlet ports arranged in a rotated manner relative to the longitudinal axes of the cylinders.

This arrangement can be used to equal advantage in the case of V-type internal combustion engines, with, for example, a narrow V angle, in which case the intake pipes of one row are assigned to one row of cylinders, forming equal intake-line lengths and the intake pipes of the other row are assigned to the other row of cylinders.

In each case, the outlets of the branch pipes are arranged along a lateral longitudinal wall of the inlet manifold casing. The difference in the length of the line from the branch pipes to the outlet openings of the inlet ports due to the rotated arrangement of the inlet ports, or the two-row arrangement of the cylinders, is compensated for by the mutually spaced staggering of the intake pipes in accordance with the present invention so that the equal intake-line lengths required for a favourable torque curve are achieved.

In an advantageous development, inlet openings of the short, closable intake pipes are arranged in mutually parallel planes within the rows, and the inlet openings of the longer intake pipes are arranged in two further planes. To achieve equal intake-line lengths as regards the longer intake pipes, these too are staggered, side by side, in a transverse direction of the internal combustion engine.

Overall, the arrangement achieved by the present invention is compact and therefore requires only a small amount of installation space, and, by virtue of the transverse staggering, can be arranged within the longitudinal extent of an internal combustion engine.

The present invention will now be further described, by way of example, with reference to the accompanying drawings wherein, the cylinder head shown can be assigned to an in-line internal combustion engine or can be the common cylinder head of a two-row V-type internal combustion engine, and in which: Fig. 1 shows a section along the line I-I in Fig.

2 of one embodiment of an air intake system constructed according to the present invention; Fig. 2 shows a plan view of the embodiment of Fig. 1; and Fig. 3 shows a view similar to that in Fig. 1 of a modified embodiment of the present invention.

In Figs. 1 and 2 of the accompanying drawings a cylinder head 1 of a multi-cylinder reciprocatingpiston internal combustion engine with a V-shaped cylinder arrangement is shown, the cylinder head 1, having short inlet ports 2 for one row of cylinders, and longer inlet ports 3 for the second row of cylinders.

Arranged above the cylinder head 1 and on both sides of a longitudinal centre plane M running in the longitudinal direction L of the internal combustion engine is an inlet manifold casing 4. This essentially comprises two parts, which are arranged adjacent to one another in a common parting plane T.

In this arrangement, a part designed as a top part 5 is attached to a part designed as a bottom part 6.

Arranged within the inlet manifold casing 4 are intake pipes of different lengths, a shorter and a longer intake pipe in each case being united by a common branch pipe 7 provided with an outlet 8. The latter is connected by means of an elbow section 9 to the inlet ports 2, 3, so that, overall, intake lines formed by the intake pipes, the elbow sections and the inlet ports are obtained.

The cylinders of one row of cylinders are each assigned a pair of intake pipes formed by a short intake pipe K1, K3, KS and a longer intake pipe L1, L3, L5. Correspondingly, the other row of cylinders has pairs formed by short intake pipes K2, K4, K6 and the associated long intake pipes L2, L4, L6.

The outlets 8 are arranged essentially along a single lateral longitudinal wall 10 of the inlet manifold casing 4.

The short intake pipes Kl...K6 are each designed in such a way that they can be closed by means of a valve device 11 designed as a butterfly. Those sections 12 of the intake pipes K1, K3, K5 which accommodate these valve devices 11 are arranged along a row 13 which runs essentially parallel to the longitudinal direction L.

Another row 14, formed by the short intake pipes K2, K4, K6, is arranged spaced apart from the abovementioned row in a transverse direction Q.

Inlet openings 15 of the sections 12 of one row 13 are arranged in a common plane El which runs parallel to another plane E2, in which inlet openings 16 of the sections 12 of the other row 14 are arranged.

Inlet openings 17 and 18 of the longer intake pipes L1, L3, L5 and L2, L4, L6, respectively, are arranged in two further planes E3 and E4 respectively, and, to form equal intake-line lengths, the longer intake pipes L1, L3, L5 and L2, L4, L6 of the respective further planes E3 and E4 are assigned to the shorter intake pipes K1, K3, K5 and K2, K4, K6 of the respective rows 13 and 14.

While the mutually parallel planes El and E2 are arranged at a relatively large angle to the longitudinal centre plane M, plane E3 is, according to Figure 1, arranged at a comparatively small angle to it, while plane E4 is perpendicular to this longitudinal centre plane M.

The modified embodiment shown in Figure 3 exhibits longer intake pipes L1...L6 in comparison with Figure 1, all these intake pipes intersecting the parting plane T and being brought back in an arc in the direction of the longitudinal centre plane M. Planes E3 and E4 are arranged essentially parallel to one another and to the longitudinal centre plane M.

To achieve as compact an arrangement of the air intake system as possible within the longitudinal extent of the internal combustion engine, the sections 12 are arranged in transverse planes of the internal combustion engine, in each case above the associated longer intake pipes.

All the intake pipes K1...K6, L1...L6 are aligned in such a way that they are arranged essentially transversely to the longitudinal direction L. As seen in the longitudinal direction L, the intake pipes assigned to one row 13 are here arranged in alternation with the intake pipes assigned to the other row 14.

Furthermore, to achieve compact dimensions in the embodiment shown in Figures 1 and 2, the inflow sections of the longer intake pipes L1, L3, L5, said inflow sections bearing the inlet openings 17, are arranged at a shallow angle relative to the parting plane T, in such a way that, referring to transverse planes of the internal combustion engine, they and the longer intake pipes L2, L4, L6 are staggered one above the other.

In the embodiment shown in Figure 3, in contrast, the long intake pipes L1, L3, L5, which end in plane E3, essentially follow the course of the other long intake pipes L2, L4 and L6, and, as a result, intake pipes LS and L6, L3 and L4, and L1 and L2 are essentially staggered adjacently and alternately in the longitudinal direction.

The embodiment shown in Figures 1 and 2 exhibits a top part 5 of comparatively simple configuration since the inlet openings of all the intake pipes are arranged below the -parting plane T. According to the embodiment in Figure 3, in contrast, the long intake pipes L1...L6 are split in the parting plane T and, as a result, planes E3 and E4 are arranged above this parting plane.

To obtain a compact arrangement which is optimized in terms of weight, outer walls of the bottom part 6 are formed at least partially by pipe walls of the sect ions 12 of one row 13 and by pipe walls of the longer intake pipes L1...L6, as can be seen from Figures 1 and 3.

During the operation of the internal combustion engine, intake air is fed to the volume of the inlet manifold casing 4 in a manner not shown. To achieve an ample torque curve even in a comparatively low speed range of the internal combustion engine, the valve devices 11 are initially closed. The entire intake air quantity is fed to the long intake pipes L1...L6 via the inlet openings 17 and 18 and passes via outlet 8, elbow section 9 and inlet ports 2 and 3 to the combust ion spaces of the cylinders. The butterfly valve devices 11 are opened from a certain operating point of the internal combustion engine onwards, as a function of the load and/or engine speed. These valve devices are each grouped with reference to rows 13 and 14 and are arranged on respective spindles 19 and 20, which can be rotated in synchronism by an actuating element [not shown]. To achieve an ample torque curve even in a comparatively high speed range of the internal combustion engine, the air drawn in now flows to the combustion spaces of the internal combustion engine primarily via the short intake pipes K1. .K6.

To achieve as uniform inlet flow conditions for all the intake pipes as possible, the inlet openings 15, 16, 17, 18 are arranged approximately at the same height in relation to the parting plane T in accordance with Figure 1, and, in accordance with Figure 3, are arranged in close proximity to this parting plane T.

The modified embodiment shown in Figure 3 is used preferentially when the intention is to push the torque to maximum - located in the low engine-speed range - towards lower engine speeds.

Claims

1. An air intake system for a multi-cylinder reciprocating-piston internal combustion engine, comprising an inlet manifold casing with intake pipes of different lengths, of which at least half can be shut off by means of valve devices, in which arrangement at least two intake pipes in each case are connected to a common branch pipe, which is provided with an outlet connected, in use, to at least one inlet port formed in a cylinder head of the internal combustion engine, all the outlets being arranged essentially along a single lateral longitudinal wall of the inlet manifold casing, the valve devices being arranged along at least two mutually spaced and essentially parallel rows running in the said longitudinal direction to close sections of the intake pipes, as desired.

2. An air intake system as claimed in claim 1, in combination with an in-line internal combustion engine, the inlet ports being assigned a respective intake pipe of one row such that one inlet port of a cylinder is assigned one intake pipe of one row and another inlet port of the same cylinder is assigned one intake pipe of the other row, in the process forming equal intake-line lengths.

3.. An air intake system as claimed in claim 1, in combination with a V-type internal cembustion engine, the inlet ports of one row of cylinders being assigned a respective intake pipe of one row and the inlet ports of the other row of cylinders are assigned a respective intake pipe of the other row.

4. An air intake system as claimed in claim 2 or claim 3, in which the intake pipes of which there are at least two, are combined in a common branch pipe, and the closable sections are assigned to the short intake pipes.

5. An air intake system as claimed in claim 4, in which inlet openings of the intake pipes of one row are arranged in a common plane which runs parallel to another plane, in which inlet openings of the intake pipes of the other row are arranged.

6. An air intake system as claimed in claim 5, in which inlet openings of the longer intake pipes are arranged in two further planes, the longer intake pipes of one and the other further plane being assigned to the shorter intake pipes of one or the other row, in the process forming equal intake-line lengths.

7. An air intake system as claimed in claim 6, in which all planes are arranged in a bottom part of the inlet manifold casing, below the parting plane.

8. An air intake system as claimed in claim 6, in which the planes assigned to the short intake pipes are formed in a bottom part of the inlet manifold casing, below the parting plane, and the planes assigned to the long intake pipes are arranged in a top part of the inlet manifold casing, above this parting plane.

9. An air intake system as claimed in one or more of the preceding claims, in which the intake pipes are arranged essentially transversely to the longitudinal direction in such a way that, in the longitudinal direction, the intake pipes of one row are arranged alternately with those of the other row.

10. An air intake system for a multi-cylinder reciprocating-piston internal combustion engine, constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.