Exhaust manifold

Abstract: A dual wall, air gap exhaust manifold has an integral inlet connecting flange 16) defining an elongated, internal , air injection passageway (36) enclosed by an L-shaped plate (50) welded over an elongated slot in the flange to form the elongated passageway, the L-shaped plate also being welded over a series of short channels (42) which extend between the elongated passageway and the manifold inlet openings. The elongated passageway has an air inlet connector (60). The spaced dual walls (20), 22) of the manifold runners are joined together at the flange openings, just downstream of the channels.

Description: This invention relates to exhaust gas manifolds for internal combustion engines such as for vehicles, and particularly to a specialised dual wall exhaust manifold preferably enabling rapid temperature rise of the catalytic converter by removing minimal thermal energy from the flow of hot combustion gases from the engine, and preferably also by exothermic combustion in the manifold itself resulting from a special, relatively simple construction. The invention also relates to exhaust air rail manifolds. The technology of internal combustion engines has for some years included knowledge that post engine combustion in the exhaust manifold of remaining combustible components in the exhaust gases reduces pollution from the ultimate exhaust gas discharge. Unfortunately, special manifold arrangements for accomplishing this have been technologically complex and expensive, usually involving a "nest" of hoses and/or tubes to the system, a complex louver system, or otherwise. The complexity not only involves an initial high cost, but also maintenance problems and expenses over the lifetime of the engine. US-A-5,349,817 describes an engine exhaust manifold with a log and the runners having an outer jacket (34) and an inner lining (30) generally spaced from each other to create an air gap therebetween. DE-U-8,914,153 describes an engine exhaust manifold with a passageway and connecting channels (10, 11) to exhaust gas inlet openings to inject additional air. However the exhaust manifold is formed of four stacked plates connected together, a channel system being punched out of the centre plate. DE-A-4,315,086 describes an engine exhaust manifold with an elongated passageway coupled to exhaust gas inlet openings to inject additional air. However, the structure for providing the passageway comprises a flange part (16) congruent with a contact part (14) for the engine block, provided with the same drill holes (28), the peripheral edges being welded or soldered together. This is a relatively complex construction requiring accurate welding. The present invention provides an engine exhaust manifold comprising a manifold log (12) and a plurality of runners (14) extending from the manifold log, each runner having an exhaust gas inlet opening (38) for conducting exhaust gases from an engine to the manifold log; the manifold log having an exhaust gas outlet (18); an elongated inlet connecting flange (16) extending over the runners at the runner openings, and having an elongated corner; an elongated cover wall (50) over the elongated corner and over the inlet connecting flange along its length to enclose an elongated passageway; the elongated passageway (36) extending adjacent all of the runners; and a connector (60) on the flange in flow-communication with the elongated passageway, and connecting channels (42) between the passageway and the exhaust gas inlet openings, whereby combustion air can be injected through said connector, the passageway and the connecting channels to the runners and manifold for chemical conversion of residual combustible components remaining in engine exhaust gases. In a preferred construction a dual wall, air gap exhaust manifold has an integral inlet connecting flange defining an elongated, internal, air injection passageway enclosed by an L-shaped plate welded over an elongated slot in the flange to form the elongated passageway, the L-shaped plate also being welded over a series of short channels which extend between the elongated passageway and the manifold inlet openings. The elongated passageway has an air inlet connector. The spaced dual walls of the manifold runners are joined together at the flange openings, just downstream of the channels. In a preferred construction a dual wall, air gap exhaust manifold has an integral inlet connecting flange defining an elongated internal passageway enclosed preferably by an L-shaped plate welded over an elongated slot in the flange to form the elongated passageway, the L-shaped plate preferably also being welded over a series of short channels which extend between the elongated passageway and the manifold inlet openings. The elongated passageway preferably has an air inlet connector. The spaced dual walls of the manifold runners are preferably joined together at the flange openings, just downstream of the channels. The dual walls of the intake manifold body or log preferably also join together at the outlet port. Such a preferred construction provides a relatively simple manifold capable of mass production, effective in operation, and free of a series of extraneous tubes and hoses. In exemplary embodiments, a dual wall structure with the air inlets is capable of minimum heat sink for the inner liner, for optimum heat up and combustion of residual combustible gases, and rapid heating of a downstream catalytic converter. These and several other features, objects and advantages of the invention will become apparent to those in the art upon studying the following specification in conjunction with the drawings. The present invention may be carried out in various ways, and a preferred embodiment of an engine exhaust manifold in accordance with the invention will not be described with reference to the accompanying drawings in which: Fig. 1 is an elevational view of a preferred embodiment of an exemplary vehicle engine exhaust manifold is accordance with the invention; Fig. 2 is a view of the manifold in Fig. 1, from an direction II-II, i.e., toward the exhaust outlet of the manifold; Fig. 3 is an end elevational view of the manifold in Fig. 1 taken from direction III-III; Fig. 4 is a fragmentary elevational view of a port flange in the manifold of Figs. 1-3; Fig. 5 is a fragmentary elevational view of the flange in Fig. 4, prior to attachment of an L-shaped cover plate; Fig. 6 is a bottom view of the flange in Fig. 5; Fig. 7 is a sectional view taken on plane VII-VII of Fig. 5; and Fig. 8 is an end elevational view taken in the direction VIII-VIII of Fig. 4. A manifold assembly 10 comprises a main body 12 from which extend a plurality of spaced runners 14, an inlet connecting flange 16 for attachment of the manifold to an engine block, and an outlet or exhaust flange 18. The body or, as it is commonly called, "log" 12 of the manifold is an elongated member in flow communication with each of the several runners, here shown to be four in number. The illustrated manifold can, for example, be for one bank of cylinders of a V-8 engine, there being a mirror image duplicate of this manifold on the opposite side of the engine. The log 12 includes an outer jacket 20 and an inner liner 22. The jacket and liner are spaced from each other preferably a controlled amount of several millimetres in width to form a dead air space serving as a heat insulator between the jacket and liner. The liner will typically be of less thickness than the jacket, both preferably being of stainless steel or other corrosion resistant material. Integrally extending from log 12 are the plurality of runners which continue the double wall construction, and are to receive exhaust gases from respective ones of the several engine cylinders. Connecting the individual runners to the inlet flange assembly 16 are individual sleeves 26 (Figs. 1 and 3). The outer end of each sleeve 26 is welded to the two engaging walls of jacket 20 and liner 22, while the inlet end of each sleeve 26 is welded to the peripheral wall of a corresponding through opening of connector plate 16. This sleeve arrangement is preferably made in accordance with the teachings of US-A-5349817. As noted, jacket 20 and liner 22 are engaged with each other circumferentially where they are joined to sleeve 26. Likewise, the jacket and liner are engaged with each other where they join discharge flange 18. This flange 18 has suitable orifices 18a such as the three depicted in Fig. 2, for attachment to an exhaust pipe of conventional or air-gap type. Inlet flange 16 is an elongated component of substantial thickness, having a plurality of bolt-receiving openings 30 (Fig. 1) at spaced intervals along its length for attachment to the engine. Shown along its upper edge is a special air injection structure to enable ambient air to be injected for oxidation purposes into the exhaust gases as they flow from the engine to the exhaust manifold assembly. More specifically, an elongated passageway 36 extends along the length of flange 16 to be adjacent to and overlap all of the plurality of exhaust gas inlet openings 38 (Fig. 2). This passageway is formed by an elongated slot or channel 40 (Fig. 7) formed into the upper outer corner of flange 16 as by machining, casting or stamping, and terminating short of the opposite ends of the flange. A plurality of short channels 42 (Fig. 7) normal to channel 40, extend between elongated channel 40 and each of openings 38 so as to allow flow communication therebetween. Covering both elongated channel 40 and the plurality of short channels 42 is an elongated, L-shaped cover plate 50. The upper horizontal leg 50a of cover plate 50 extends over the top of channel 40 and is welded to the upper surface of connector plate 16. The vertical leg 50b of cover plate 50, which is normal to 50a, extends over the side of channel 40 as well as over short channels 42, and is welded to the side face of connector plate 16 as well as to the adjacent area of sleeves 26, thereby enclosing channels 40 and 42 from the ambient atmosphere. An air inlet conduit 60 having a threaded outer end 60a is welded to plate 16 at one end of passageway 36, so that oxygen-bearing air can be injected into passageway 36 and thus into the hot exhaust gases flowing through ports 38 into the exhaust manifold, where further combustion occurs, including conversion of carbon monoxide to carbon dioxide with the added oxygen, due to the maintained high temperature of the exhaust gas and the presence of the additional oxidizing gas, i.e., air. The combined heat of the exhaust gases flowing from the engine and the further combustion occurring in the exhaust manifold during start-up causes the inner liner 22 to rapidly heat to an elevated temperature while the outer jacket is thermally insulated by the air gap. The apparatus has been found very effective, simple to fabricate, relatively inexpensive, and highly effective to oxidize the noxious gases such as carbon monoxide and oxides of nitrogen and sulfur emitted from the engine. It is conceivable that certain minor variations may be made in the illustrated structure which is the preferred embodiment set forth as exemplary of the invention. Therefore, the invention is not intended to be limited to this specific embodiment, but only by the scope of the appended claims.

Claims: An engine exhaust manifold comprising: a manifold log (12) and a plurality of runners (14) extending from the manifold log, each runner having an exhaust gas inlet opening (38); an elongated, inlet connecting flange (16) extending over the runners at the openings and having mounting orifices for attachment of the manifold to an internal combustion engine, and having an elongated corner; the elongated, inlet connecting flange and an elongated cover (50) forming an elongated passageway (36) extending adjacent the runners, and the elongated, inlet connecting flange having a plurality of short channels (42) extending from the elongated passageway to the inlet openings; and a connector (60) on the inlet connecting flange and in flow-communication with the elongated passageway, whereby combustion air can be injected through the connector, the passageway and the connecting channels to the runners of the manifold for chemical reaction of residual combustible components in engine exhaust gas; characterised in that the elongated cover wall (50) is disposed over the elongated corner formed by an elongated channel (40) in the elongated inlet connecting flange (16), and is welded to the inlet connecting flange along its length to enclose said elongated passageway. An engine exhaust manifold as claimed in claim 1 wherein the elongated cover wall is L-shaped. An engine exhaust manifold as claimed in claim 2 wherein the elongated L-shaped cover wall (50) covers the elongated channel (40) and the connecting channels (42) to enclose all of said channels. An engine exhaust manifold according to any preceding claim, the elongated, inlet connecting flange having a plurality of short channels (42) extending from the elongated channel (40) to the inlet openings (38); the elongated cover (50) being welded to the inlet connecting flange over the elongated channel (40) and over the short channels (42) to form an elongated passageway extending along all of the runners, and form short connecting channels (42) between the passageway and said runners. An engine exhaust manifold as claimed in any one of the preceding claims in which the log and the runners have an outer jacket (20) and an inner liner (22) generally spaced from each other to create an air gap therebetween, the jacket and liner being joined together adjacent the inlet connecting flange and adjacent the exhaust gas outlet, whereby the inner liner can be heated rapidly by exhaust gases entering the runners and by combustion in the manifold.

Inventors: BEKKERING MARK WAYNE, MATTSON EARL WILLARD, THOMAS ERNEST CHARLES, BEKKERING, MARK WAYNE, MATTSON, EARL WILLARD, THOMAS, ERNEST CHARLES
Applicants: BENTELER IND INC, BENTELER INDUSTRIES, INC.
Application year: 1995
Main classification: F01N7
IPC codes: F01N3, F01N13