TECHNICAL FIELD

The disclosure relates to the field of intake manifolds for internal combustion engines, in particular for automotive vehicles, especially front- engine automotive vehicles with forward-facing intake manifolds.

BACKGROUND

In a common configuration, automotive vehicles have a front engine oriented transversely to the direction of travel. In this configuration, the intake manifold of the internal combustion engine will normally be located on a front side of the internal combustion engine, to facilitate the airflow into the internal combustion engine. Fuel lines will normally be located in the vicinity of the intake manifold, more specifically adjacent to its downstream ports connecting to the cylinder head.

However, in this configuration, a frontal impact may strike and break the intake manifold, and the broken intake manifold may damage the fuel lines. Fuel then leaking from the damaged fuel lines onto hot vehicle components, such as the engine block or the exhaust system, may then constitute a significant fire risk.

It has been proposed, for instance in US patent No. 7,210,461 B2, to incorporate a fragile zone in the intake manifold, so that it breaks according to a predetermined pattern, and protective elements in the vicinity of the fuel lines, specifically to protect them from the broken intake manifold. However, the incorporation of such protective elements may add weight and complexity to the intake manifold.

SUMMARY

A first object of the disclosure is that of preventing that the intake manifold, after being broken by an impact, damages any fuel lines in the vicinity.

For this purpose, an intake manifold according to a first aspect of the invention may comprise a plenum chamber, a plurality of ducts, and one or more stiffening ribs. The ducts may connect the plenum chamber to a plurality of downstream ports located, on a side of the intake manifold, above the plenum chamber. The plurality of ducts may extend in a first direction from the plurality of downstream ports and be curved in a second direction, orthogonal to the first direction, towards the plenum chamber. The stiffening ribs may extend, on said side of the intake manifold, from the plurality of downstream ports towards the plenum chamber, and have a fragile zone at a distance forward from the plurality of downstream ports.

Consequently, an impact on the intake manifold may break the intake manifold at the fragile zone of the stiffening ribs, away from the downstream ports on whose vicinity the fuel lines may be located, preventing contact of the broken-off part of the intake manifold with the fuel lines.

To clearly determine the fragile zone, and facilitate a clean break of the intake manifold by concentrating stress there, the fragile zone may be formed by a cutout, in particular a triangular cutout, on each stiffening rib of the one or more stiffening ribs.

The intake manifold may comprise a first part and a second part, wherein the first part may comprise the plurality of downstream ports, and the first part and the second part may be bonded together transversally to the plurality of ducts, for example by welding. To maintain adequate stiffness of the intake manifold against inner pressure, a strut may extend in the second direction from the plurality of ducts to the plenum chamber. In this case, to still facilitate bending and breakage at the fragile zone under an impact stress, the strut may be longitudinally split between the first part and the second part, and the first part and the second part may not be bonded to each other over at least part of the strut.

For low weight and cost of production, the intake manifold may be made of a fiber-reinforced organic polymer material such as e.g. glass- fiber-reinforced polyamide. A second aspect of the present disclosure relates to an internal combustion engine which may comprise the intake manifold of the first aspect, and one or more fuel lines adjacent to the plurality of downstream ports of the intake manifold. In particular, the fuel lines may be adjacent in the second direction and/or in a third direction opposite to the second direction to the plurality of downstream ports of the intake manifold. A third aspect of the present disclosure relates to a vehicle comprising the internal combustion engine according to the second aspect, wherein the internal combustion engine may be located at a front end of the vehicle, with the intake manifold on a front side of the internal combustion engine. The first direction may be a forward direction, the second direction a downward direction, and said side of the intake manifold a rear side of the intake manifold. However, vehicles with different configurations, e.g. with the internal combustion engine at the rear and/or longitudinally oriented, may also be considered. A fourth aspect of the present disclosure relates to a method of protecting one or more fuel lines of an internal combustion engine of a front-engine vehicle against a frontal impact. The internal combustion engine may comprise an intake manifold, located on a front side of the internal combustion engine. The intake manifold may include a plenum chamber and a plurality of ducts connecting the plenum chamber to a plurality of downstream ports located on a rear side of the intake manifold. The plurality of ducts may extend forward from the plurality of downstream ports and be downwardly curved towards the plenum chamber, and the fuel lines may be adjacent to the plurality of downstream ports of the intake manifold. The frontal impact may generate a bending load on the plurality of ducts forward from the plurality of downstream ports. The intake manifold may break, under this bending load, at a fragile zone located, at a distance from the plurality of corresponding ports, on one or more stiffening ribs extending, on the rear side of the intake manifold, from the plurality of corresponding ports towards the plenum chamber.

The above summary of some aspects is not intended to describe each disclosed embodiment or every implementation of the invention. In particular, selected features of any illustrative embodiment within this specification may be incorporated into an additional embodiment unless clearly stated to the contrary.

BRIEF DESCRIPTION OF THE DRAWINGS The invention may be more completely understood in consideration of the following detailed description of various embodiments in connection with the accompanying drawings, in which: - FIG. 1 schematically illustrates an automotive vehicle with an engine in a front transverse engine configuration;

- FIG. 2 is a perspective front view of the intake manifold of FIG. 1;

- FIG. 3 is a perspective rear view of the intake manifold of FIG. 1;

- FIG. 4 is a perspective exploded view of the intake manifold of FIG. 1;

- FIG. 5 is a detail view of the intake manifold of FIG. 1;

- FIGS. 6 and 7 are side views of the intake manifold of FIG. 1; and

- FIGS. 8 and 9 are cross-cut views of the intake manifold of FIG. 1. While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention.

DETAILED DESCRIPTION

For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification.

As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise.

The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The detailed description and the drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention. The illustrative embodiments depicted are intended only as exemplary. Selected features of any illustrative embodiment may be incorporated into an additional embodiment unless clearly stated to the contrary. An automotive vehicle 1 is illustrated in FIG. 1. Throughout the present disclosure, the terms "front", "rear", "transverse", "forward", "downward", "above" and "below" should be understood with respect to the reference frame of such a vehicle, extending longitudinally in the forward direction FWD from the rear end 2 to the front end 3, and vertically in the upward direction UP from the ground 4 to the roof 5 of the vehicle 1. As in the illustrated example, the vehicle 1 may comprise an internal combustion engine 10 located at the front end 3 of the vehicle 1, and transversely oriented. However, alternative configurations may be considered, e.g. with the internal combustion engine 10 located at the rear end 2 or the middle of the vehicle 1, and/or longitudinally oriented. As shown in FIG. 1, the internal combustion engine 10 may comprise a multi-cylinder engine block 11 with a corresponding cylinder head 12, and an inlet manifold 100 to feed air into the internal combustion engine 10. The inlet manifold may be located, as shown, on a front side of the internal combustion engine 10, in order to facilitate the entry of air into the internal combustion engine 10, although alternative lateral or rear positions may also be considered, in particular if the internal combustion engine 10 is located elsewhere than at the front end of the vehicle 1 and/or longitudinally oriented.

As also shown in FIGS. 1 to 3, the inlet manifold 100 may comprise a plenum chamber 101 (also known as "airbox" and even "surge tank") and a plurality of ducts 102. Each duct 102 may connect the plenum chamber 101 to one of a plurality of downstream ports 103, and each one of these downstream ports 103 may connect to a corresponding inlet port in the cylinder head 12, so that incoming air may flow from the plenum chamber to the individual cylinders of the internal combustion engine 10 through the ducts 12, the downstream ports 103, and corresponding inlets in the cylinder head 12. For this, the downstream ports 103 may be located on a rear side 100R of the inlet manifold 100, shown on FIG. 3, although different sides may be considered, depending on the position and orientation of the internal combustion engine 10 and of the inlet manifold 100. The internal combustion engine 10 may also include a fuel system with fuel lines 13, 14, which may be located adjacent to the downstream ports 103, in particular over and/or under these downstream ports 103, as illustrated. The phrase "fuel line" should be understood in a broad sense, extending to e.g. fuel rails in internal combustion engines and fuel ducts leading to various sensors, such as e.g. fuel quality or pressure sensors. As shown in FIG. 4, the inlet manifold 100, which may be made in a fiber-reinforced organic polymer such as glass-fiber-reinforced polyamide, and more particularly PA6-GF30, may be formed by several parts 110, 120, 130, 140, welded together. A lower body of the inlet manifold 100 may form a first part 110, a middle body of the inlet manifold 100 may form a second part 120, and an upper body of the inlet manifold 100 may form a third part 130, wherein the second part 120 may be held between the first and third parts 110, 130. An exhaust gas recycling (EGR) cap may form a fourth part 140, joined to the third part 130. Each duct 102 may extend forward from the corresponding downstream port 103, curving downwards towards the plenum chamber

101. The first part 110 of the inlet manifold 100 may comprise the downstream ports 103 and an adjacent end segment 102e of each duct

102. In order to stiffen the inlet manifold 100 against the internal air pressure, the first part 110 may also comprise one or more stiffening ribs

111 extending, on the rear side 100R of the inlet manifold 100, from the plurality of downstream ports towards the plenum chamber 101, as shown in particular in FIGS. 5 to 8. For the same purpose, a strut 104 may also extend downwards, from the plurality of ducts 102 to the plenum chamber 101, as shown in particular in FIGS. 5 and 9. This strut 104 may be aligned with a plane P, transversal to the ducts 102, and forwardly offset from the downstream ports 103, where the first and second parts 110, 120 are bonded together at these ducts 102. The strut 104 may be split lengthwise between the first and second parts 110, 120. The stiffening ribs 111 may have triangular cutouts 112, with their apexes aligned along a hinge line L to form a fragile zone 113 forwardly offset from the downstream ports 103. The first and second parts 110, 120 may also not be bonded to each other over at least a segment of the strut 104, which may also be close to hinge line L In case of a frontal impact on the inlet manifold 100, the inlet manifold 100 may thus be set to bend and crack at the fragile zone 113, at a distance forward from the downstream ports 103 and adjacent fuel lines 13, 14. The inlet manifold 100 may thus split along a crack line 114, as shown on FIGS. 6 and 7, from the fragile zone 113 to the front side 100F of the inlet manifold 100, so that the downstream ports 103 may thus remain attached to the cylinder head 12, together with the adjacent end segments 102e of the ducts 102, still stiffened by the stiffening ribs 111, shielding the fuel lines 13, 14, while the remainder of the inlet manifold 100 may roll below hinge line L, pushed by the frontal impact. The fuel lines 13, 14 will thus be protected from the frontal impact. Those skilled in the art will recognize that the present invention may be manifested in a variety of forms other than the specific embodiments described and contemplated herein. Accordingly, departure in form and detail may be made without departing from the scope of the present invention as described in the appended claims.