Exhaust manifold having improved NVH characteristics

Abstract

An exhaust manifold and method of manufacturing the same is provided that includes at least one tube within shells of an exhaust manifold. The tube limits fluid communication from the tube into the shells of the exhaust manifold. An inlet flange is connectable to the exhaust manifold and is attachable to a cylinder head of a combustion engine. Exhaust gases expelled from the cylinder head are transmitted into the exhaust manifold. At least a portion of the exhaust gases pass through the tube. The exhaust manifold reduces NVH and cures emission control issues.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims benefit from U.S. Provisional Patent Application No. 60 / 934,376, entitled “Exhaust Manifold Having Improved NVH Characteristics,” filed on Jun. 13, 2007, which is hereby incorporated in its entirety by reference.FIELD OF THE INVENTION[0002]This invention generally relates to an exhaust manifold that may be incorporated into an internal combustion engine, and more particularly to an exhaust manifold having exhaust tubes within an exhaust manifold housing that may improve noise, vibration and harness characteristics of the manifold housing.BACKGROUND[0003]In an internal combustion engine, a cylinder head is positioned atop an engine block having cylinders (or combustion chambers) extending therethrough. Upper portions of each combustion chamber extend through the cylinder head, where the upper portion of each combustion chamber corresponds with each cylinder of the engine block. The cylinder head may also house intak...

AI Technical Summary

Benefits of technology

[0009]An exhaust manifold assembly is provided. The exhaust manifold assembly may consist of an upper half shell secured to a lower half shell to form a housing. The upper half shell and / or the lower half shell may have one or more tubes extending within the interior of the housing. An inlet flange and an outlet flange may be attached to one of the shells. The inlet flange may be attached to a cylinder head to receive exhaust gases from the cylinder head. The exhaust gases may be received by the one or more tubes. Advantageously, the improved exhaust manifold assembly may reduce NVH.

Problems solved by technology

However, these manifolds are heavy, cumbersome, and therefore detract from the fuel efficiency of the vehicle.

In addition, the cast iron manifolds are difficult to manufacture into compact shapes and other distinct shapes as may be required by the underhood packaging constraints of modern vehicles.

However, these sheet metal manifolds present several disadvantages.

In particular, since the sheet metal manifolds are thin and lighter in weight, the sheet metal manifolds provide noise, vibration, and harshness (“NVH”) problems.

For example, the NVH problems present objectionable noise and vibration from the exhaust pulses.

Furthermore, the sharing of exhaust pulses among cylinders via the exhaust manifold (i.e. “cross-talk”) may compound the NVH problems and may result in further objectionable noise and vibration.

The NVH transmitted and experienced by the passengers is bothersome and undesirable.

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