FR2644207A1 - Exhaust manifold for an internal combustion engine - Google Patents

Abstract

Exhaust manifold of the type comprising branches which, at one end, join to a flange 3 for fixing to the cylinder head and, at the other end, to a flange 4 for fixing to the exhaust pipe. According to the invention, it includes two half-shells 6, 7 each one consisting of two, inner 2 and outer 1 metal sheets separated at every point by an air gap 5. Application: particularly to high-performance engines.

Description

COLL @ CTEUR D'EC @@ PP @ MEST POUR MOT @ UR @ CO @@ USTION I @ TER @ E
The present invention relates to an exhaust manifold for between the engine block and the exhaust port. It more specifically relates to an exhaust manifold made up of sheet metal half-shells assembled by welding at the level of their common separation plane. The engines of current manufacture manufactured by molding.

 The present invention aims to provide an exhaust manifold which, on the one hand, withstands high temperatures and, on the other hand, reduces heat transfers between the exhaust gases and compartmentalize the powertrain.

 In accordance with the invention and according to an essential feature, this exhaust manifold, of the type comprising co @ lines joining at one end to a mounting flange on the cylinder head, and at the other end to a mounting flange on the exhaust pipe, comprises two half-shells each consisting of two sheets, one internal and the other external, separated at all points by a la @ e of air.

 This arrangement provides less thermal inertia for the steel outer shell. It makes it possible to limit, by means of the insulating air gap, the heat transfers between the exhaust gases and the walls of the manifold. These two aspects lead to a limitation of transfers from the collector to the compartment of the powertrain.

Other features and particularities will emerge more clearly from the following description of a preferred embodiment, given by way of nonlimiting example, with reference to the appended drawings in which:
FIG. 1 represents a front perspective view of a manifold with four conduits according to the invention,
FIG. 2 represents a profile view of this collector, in partial section along the longitudinal axis of one of the conduits,
- And Figure 3 shows an axial sectional view of the flange for fixing this manifold to an exhaust pipe.

 Figure 1 shows an exhaust manifold for an in-line four-cylinder engine. As shown in Figure 2, this manifold is composed of two deni-shells (6,7) which delimit, after their assembly, a curved conduit. Each of the open ends of these conduits is mounted on a flange (3) which allows the manifold to be tightly connected to the exhaust openings of the oulasse. Each of the two half - @@ keels consists of an external steel sheet (1) and an internal steel sheet (2), separated by an air space (5). These steel sheets (1,2) have a thickness of approximately 1.5 mm and the air space (5) a thickness of the order of 3 mm. the outer steel sheet (1) must preferably resist heat and the inner steel sheet (2) withstand hot oxidation.

 A flange (4) detailed in Figure 3 allows to connect the four pipes from the manifold to the engine exhaust pipe.

 This exhaust manifold arrangement allows don @ to limit transfers from the manifold to the compartment of the powertrain. It thus allows the elimination of thermal protection screens, and the use of materials which are less expensive and / or more melting point in the environment of the engine.

 This results in view of the fact that the exhaust gases are hotter, a greater latitude for the positioning of the catalytic converter relative to the engine, and / or a faster reaction of this catalytic converter.

Claims (3)

 1- Exhaust manifold for internal combustion engine, of the type comprising ze conduits connected at one end to a flange (3) on the cylinder head, and at the other end to a flange (4) for fixing on the exhaust pipe, characterized in that it comprises two half-shells (6,7) each consisting of two internal (2) and external (1) sheets separated at all points by an air gap (5)  2 - Collector according to claim 1, characterized in that the internal sheet (2) is a steel sheet resistant to hot oxidation while the external sheet (1) is a steel sheet resistant to heat.  3 - Collector according to claims 1 and 2, characterized in that the internal (2) and external (1) sheets each have a thickness of about 1.5 mm, and the air space (5) a thickness of l 'order of double.