Exhaust manifold for a combustion engine

Abstract: An exhaust manifold (20) for a combustion engine includes a flow deflector member (40) to redirect the flow of exhaust through the catalytic converter in the exhaust system. The deflector member (40) is in the shape of a ring conforming to the inner diameter of the manifold (20) for secure mounting therein. The deflector ring (40) has a center opening (42) and an inwardly angled deflector wall (46) which directs flow through the opening (42). Exhaust flow along the walls of the manifold (20) is redirected inwardly by the deflector ring (40) to optimize flow distribution through the exhaust system.

Description: Background Of The Invention I. Field of the Invention This invention relates to an exhaust manifold for a combustion engine. II. Description of the Prior Art As restrictions on exhaust emissions and fuel economy in passenger vehicles have increased, and market demands for passenger comfort have increased, vehicle manufacturers must continuously seek design improvements. These improvements are implemented within the engine compartment as well as the passenger compartment. Improved emission control devices are being added within the exhaust system. At the same time, manufacturers must fit these devices.within an increasingly cramped space in order to maintain the roominess of the passenger compartment. As a result, exhaust manifolds are designed to strict tolerances to direct combustion gases from the exhaust ports of the engine through a collector to the remainder of the exhaust system. As part of the emission control system of modern vehicles a catalytic converter has been inserted at the outlet of the exhaust manifold to reduce emissions prior to the main catalytic converter. It has been determined that the compact design of modern exhaust manifolds tends to direct a significant volume of the exhaust towards the outside of manifold bends. This proportion of the exhaust gas will affect the emission control materials within the converter. In this connection, document US-A-4 420 933 discloses an exhaust manifold in a multicylinder engine, comprising a plurality of elongate exhaust passages in communication with respectively cylinders in the multicylinder engine, a manifold chamber in communication with the elongate exhaust passages, the manifold chamber having an inner oblately spheroidal surface, and a restricted outlet from the manifold chamber in communication with a catalyst. According to this prior art, the manifold chamber outlet is defined by a hole through both a mounting flange of the manifold and a mounting flange of an associated catalyst carrier. Finally, document WO-A-00/47878 (EP-A-1 151 184) which is comprised in the state of the art pursuant to Articles 54 (3) and (4) EPC, discloses an exhaust system comprising an exhaust manifold for merging the exhaust-gas streams arriving from two or more cylinders of an internal combustion engine. The manifold comprises an exhaust cross-section downstream of which a jacket tube is connected which houses a honeycomb. Between the exhaust cross-section and the honeycomb a chamber is positioned through which the exhaust gas is able to flow and in which a plane baffle plate for deflecting at least part of the exhaust-gas streams is arranged. Summary Of The Present Invention The present invention aims at providing a convenient and economical means of optimizing the flow of exhaust through the emission control device. This object is solved by the features contained in claim 1. Advantageously developed embodiments of the invention are subject-matter of the dependent claims 2 to 8. According to the invention there is provided an exhaust manifold for a combustion engine, the manifold having a collector chamber with an inner surface and an outlet, wherein a flow deflector member is disposed within the collector chamber of the manifold for redirecting the flow of exhaust within the manifold, the flow deflector member being ring shaped with an inner opening, and including a deflector wall which is angled inwardly and towards a downstream side of the flow deflector member for directing the flow of exhaust through the inner opening. Thus, the present invention overcomes the disadvantages of the prior known exhaust manifolds by providing a deflector member positioned within the collector chamber of the manifold to optimize exhaust flow from the manifold. In a preferred embodiment the deflector member is positioned proximate the outlet of an engine exhaust manifold. The deflector is in the form of a ring having a center port such that exhaust flow is directed away from the outer walls of the manifold and toward the center of the catalytic converter. The exhaust manifold includes a plurality of arms corresponding to the number of exhaust chambers of the engine. The arms are connected to the exhaust ports to provide fluid communication between the engine and the exhaust system. The exhaust arms are in communication with a collector chamber having an outlet port connected to the remainder of the exhaust system. Proximate the outlet of the exhaust manifold is a catalytic converter or similar emission control device which provides a first stage of emission control. However, because of the proximity of the emission control device to the outlet of the exhaust manifold, the flow distribution of the exhaust gases through the converter must be optimized to prevent premature erosion of some sections of the converter while also enhancing the overall performance of the converter. In order to distribute exhaust flow, the deflector member is positioned at the outlet of the manifold. In a preferred embodiment, the deflector is a ring conforming to the configuration of the manifold walls with a central opening through which the exhaust is directed. The body of the ring includes an outer wall of securing the deflector member to the manifold and an inwardly angled wall for directing exhaust flow away from the manifold walls through the deflector ring. The deflector for redirecting the gas flow improves utilization of the catalytic converter brick while also reducing wear of the catalytic material by reducing convergence of the exhaust gases. Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings. Brief Description Of The Drawing The present invention will be more fully understood by reference to the following detailed description of a preferred embodiment of the present invention when read in conjunction with the accompanying drawing, in which like reference characters refer to like parts throughout the views and in which: FIGURE 1 is a perspective view of an exhaust manifold embodying the present invention; FIGURE 2 is an end view of the exhaust manifold showing a flow deflector member mounted within the outlet; and FIGURE 3 is a schematic view of the manifold depicting the exhaust flow therethrough. Detailed Description Of A Preferred Embodiment Of The Present Invention Referring first to Figure 1, there is shown a portion of an engine cylinder head 10 to which is secured an exhaust manifold 20 embodying the present invention. The engine 10 will include a plurality of exhaust ports 12 corresponding to the number of piston cylinders of the engine. The exhaust ports 12 may be disposed on opposite sides of the engine 10 requiring dual exhaust manifolds 20. The engine 10 includes threaded bores 14 proximate the exhaust ports 12 for receiving corresponding fasteners 16 to sealingly secure the exhaust manifold 20 in fluid communication with the exhaust ports 12. The exhaust manifold 20 is designed to collect exhaust gases from the engine 10 and efficiently direct the exhaust through the emission control devices of the exhaust system (not shown). The manifold 20 typically includes a plurality of arms 22 corresponding to the exhaust ports 12 and a main body or collector chamber 24 in communication with the arms 22. The arms 22 and collector chamber 24 are configured to facilitate the smooth flow of exhaust gases to the exhaust system without creating disruptive turbulence or backflow of gases. The arms 22 include mounting flanges 26 for receiving the fasteners 16 to secure the manifold 20 to the engine 10. Remote from the inlet arms 22 is an outlet 28 of the collector chamber 24 which is connected to the remainder of the exhaust system. The manifold 20 may include additional ports 32 for mounting monitoring devices such as emission sensors. Referring now to Figures 2 and 3, secured within the outlet 28 of the manifold 20 is a flow deflector member 40 for optimizing the flow of exhaust gases from the manifold 20 across an emission control device (not shown) connected to the manifold 20. The deflector 40 is secured to the interior peripheral wall 34 of the manifold collector chamber 24 and therefore conforms to the configuration of the chamber 24. The deflector 40 is ring shaped with an inner opening 42 through which emission gases can flow (Fig. 3). The deflector member 40 has an outer wall 44 conforming to the inner periphery 34 of the chamber 24. The outer wall 44 is staked and welded or otherwise secured to the wall 34 of the manifold 20. Disposed radially inwardly from the outer wall 44 is a deflector wall 46. The deflector wall 46 is preferably angled inwardly and towards the downstream side of the deflector member 40. The angle of the deflector wall 46 will cause the exhaust gas to flow away from the outer walls 34 of the manifold 20 through the opening 42 for a more even distribution across the emission control device. In the conventional manifold, the exhaust flow will tend to follow the outside curvature of the manifold wall concentrating the exhaust over a portion of the emission control device. The deflector ring 40 of the present invention provides a convenient and economical means of optimizing the flow of exhaust through the emission control device. Summarily, an exhaust manifold for a combustion engine includes a flow deflector member to redirect the flow of exhaust through the catalytic converter in the exhaust system. The deflector member is in the shape of a ring conforming to the inner diameter of the manifold for secure mounting therein. The deflector ring has a center opening and an inwardly angled deflector wall which directs flow through the opening. Exhaust flow along the walls of the manifold is redirected inwardly by the deflector ring to optimize flow distribution through the exhaust system.

Claims: An exhaust manifold (20) for a combustion engine, the manifold (20) having a collector chamber (24) with an inner surface and an outlet (28), wherein a flow deflector member (40) is disposed within the collector chamber (24) of the manifold (20) for redirecting the flow of exhaust within said manifold (20), said flow deflector member (40) being ring shaped with an inner opening (42), and including a deflector wall (46) which is angled inwardly and towards a downstream side of the flow deflector member (40) for directing the flow of exhaust through said inner opening (42). The manifold (20) as defined in claim 1, wherein said flow deflector member (40) is mounted proximate said outlet (28) of said collector chamber (24) for redirecting exhaust flow leaving said manifold (20). The manifold (20) as defined in claim 1 or 2, wherein said flow deflector member (40) forms a ring substantially conforming to a wall (34) of said collector chamber (24). The manifold (20) as defined in claim 3, wherein said flow deflector member (40) has an outer wall (44) conforming to an inner surface of said collector chamber (24) such that said outer wall (44) of said deflector member (40) is in flush engagement with said inner surface of said collector chamber (24). The manifold (20) as defined in claim 4, wherein said outer wall (44) of said deflector member (40) is attached to said chamber inner surface. The manifold (20) as defined in claim 4 or 5, wherein said deflector wall (46) is disposed radially inwardly of said outer wall (44). The manifold (20) as defined in claim 6, wherein said deflector wall (46) is integrally formed with said outer wall (44) to form a single piece deflector ring (40). The manifold (20) as defined in one of the preceding claims, comprising a manifold body having a plurality of arms (22) for connection to the combustion engine, said arms (22) being in fluid communication with said collector chamber (24).

Inventors: KENYON PAUL W, KETELHUT THOMAS, STEMPIEN VINCENT, KENYON, PAUL W., KETELHUT; THOMAS, STEMPIEN, VINCENT
Applicants: MASCOTECH TUBULAR PROD INC, MASCOTECH TUBULAR PRODUCTS, INC.
Application year: 2000
Main classification: F01N7
IPC codes: F01N3, F01N7