GB1579276A

GB1579276A - Heat exchanger for cooling exhaust gas

Info

Publication number: GB1579276A
Application number: GB13656/79A
Authority: GB
Original assignee: Borg Warner Corp
Current assignee: Borg Warner Corp
Priority date: 1976-08-23
Filing date: 1977-06-22
Publication date: 1980-11-19
Also published as: JPS6133972B2; JPS6223236B2; DE2733215A1; SE8303353L; SE7708696L; CA1090778A; DE2733215C3; FR2363073A1; GB1579275A; DE2733215B2; DE2759785C2; SE429675B; FR2363073B1; SE8303353D0; JPS5325717A; AU518454B2; AU2655677A; JPS6183881A

Description

PATENT SPECIFICATION

( 11) 1579276 ( 21) Application No 13656/79 ( 22) Filed 22 June 1977 ( 19) ( 31) Convention Application No 716628 ( 32) Filed 23 Aug 1976 in ( 33) United States of America (US) ( 44) Complete Specification published 19 Nov 1980 ( 51) INT CL 3 F 28 F 3/00 ( 52) Index at acceptance F 4 S:4 G 4 U 15 ( 62)' Divided out of No 1,579,275 ( 54) HEAT EXCHANGER FOR COOLING EXHAUST GAS ( 71) We, BORG-WARNER CORPORATION, a Corporation organised and existing under the laws of the State of Delaware, United States of America, of 200 South Michigan Avenue, Chicago, State of Illinois 60604, United States of America, do hereby declare the invention' for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the

following statement:

The present invention relates to exhaust gas recirculation in the automotive internal combustion engine and more particularly to a heat exchanger which may be used for cooling the exhaust 'gas that is returned to the combustion cycle Since approximately 1971, automotive vehicle manufacturers have been required to add an ever-increasing number of components or systems to the vehicle or to the internal combustion engine therein to increase the safety of the vehicle or decrease the emissions inherent in the exhaust gases from the internal combustion engine Such components include positive crankcase ventilation, exhaust gas recirculation, an evaporation control system and a catalytic converter in the exhaust line.

Of major concern is the emissions from the exhaust gas of an internal combustion cycle which have been blamed for conditions such as smog occurring in large cities where a large number of automobiles are present each day The oxides of nitrogen are one such emission, and an exhaust gas recirculation cycle is used to reduce these oxides present in the engine exhaust Formation of nitrogen oxides takes place at very high temperatures and consequently occurs during the peak temperature period of the combustion process To reduce and control nitrogen oxides formation, only a slight reduction in peak temperature is required.

This temperature reduction can be accomplished by introducing small 'amounts of an inert gas into the combustion process and, as the end products of combustion provide a continuous supply of relatively inert gases, it becomes a matter of'utilising those gases in the correct proportion' Thus, a recirculation passage is connected to the exhaust manifold and to a vacuum'modulated shutoff and metering valve installed on the inlet manifold to 'control the flow of exhaust gases The recirculation or additional exhaust gas passages are' closely positioned' to the engine or may be cast into the 'complex runner system of the inlet manifold ' However, the exhaust gases from the internal combustion engine cycle aie still at a very high temperature level and it is desirable to substantially reduce that ' temperature level before the gases are reintroduced into the combustion cycle The present invention is directed at providing a heat exchanger for use in obtaining this desired temperature reduction.

The present invention comprehends the provision of a heat exchanger to be inserted in the exhaust gas recirculation system of an automotive internal combustion engine to cool the recirculating exhaust gases before reintroduction into the inlet manifold The heat exchanger is of a compact'design to fit within the relatively crowded 'space in the engine compartment of the vehicle and to be easily mounted on the engine without substantially increasing the flow path of the recirculating gases.

According to the present invention there is provided a heat exchanger comprising a plurality of spaced-apart similar plates joined together in a stack between two endmost plates, the plates each comprising a peripheral first flange portion, an inlet opening for a first fluid and an outlet opening for the first fluid therethrough, each opening being surrounded by second and third flange portions of the plate, and one or more passage openings through the plate for the passage of the second fluid and each surrounded by a further flange portion, all the flange portions extending to the'same height from one surface of the plate with the flanges of'each flanged plate in the stack engaging an unflanged surface of an adjacent plate, one of the endmost ' plates being unflanged and having no inlet and outlet Ir_ 2 ' 1,579,276 2 ' openings therethrough for the passage of the first' fluid, and means being provided for permitting flow of said first fluid in the stack from'the inlet: penings to the outlet openings 5:' via the plate interspaces, and means at one end of the stack'for the connection of feed i:and return conduits for said first fluid to the >'; inlet and outlet openings at that end of the p: ''stack aind means at both ends of the stack 1 O%; f:'ricol'heting the passage openings for flow of tfel -seccond fluid through said passage openings from end to end of the stack.

The invention will be further described, by way of example, with reference to the.

accompanying drawings, in which:

Figure 1 is a perspective view of a heat -exchanger embodying the invention but with :the ends of the heat exchanger Omitted;:

: Figure -2 is a top plan view of the heat exchanger: of Figure 1 including the 'end pieces:and with the'front and rear portions ::broken away; ' : Figure 2 is a vertical cross sectional view taken on the line 3 t 3 of Figure 2; and ' Figure 4 is a 'vertical cross sectional:"view of a heat exchanger -plate taken on the line 4-4 of Figure'3 '' '' 'Referring to the drawings an exhaust gas heat-exchanger 111 fof use' in the exhaust gas recirculation line' of an automotive internal combustion-engine is provided "' The heat exchanger 111 utilises'a plurality -of generally elliptical perforated plates '112 which are stacked together to form the heat exchanger Each plate 112 is stamped to form :a peripheral flange 1 '13; a gas inlet opening 114 defined by a flange '115 a gas outlet opening 116 defined by a flange 1 '17 and several 'elongated' narrow openings 118 40:defined by flanges 119 All of the flanges 113, 115, 117 and 119 "project from one surface 121 of the plate 112, and all of the'plates are similarly oriented so that the flanges of one plate abut the unflanged surface 122 of lthe ' next adjacent plate Each respective get of openings and flanges are axially aligned to form a continuous passage through the plates.

Each plate 112 may be imperforate but preferably has a series of slits or louvres 123 formed therein between the openings 114 and 116 to enhance the-heat transfer from hot exhaust gas to cooling fluid, e g water The front end plate 112 a includes exhaust gas inlet and outlet openings '114 and 1 '16 and the narrow openings 118; but without 'the slits, and the rear end plate 112 b is similar to the plate 112 a except that whilst there are openings 118 therein, there are no flanges or gas inlet and outlet openings Also each flange 115, 117 has one or more'openings 124, 125, respectively, formed therein, to allow the exhaust gases to pass' transversely across and between the plates A domed end cap 126 is secured to the front end plate 122 a and has an inlet conduit 127 defined by a flange 128 and an outlet conduit 129 defined by a flange 131; the flanges 128, 131 being aligned with the openings 114 and 116, respectively, and secured to the plate 112 a A cooling fluid inlet conduit 132 is also formed in the end cap 126 and communicates with a chamber 133 therein to distribute fluid to the openings 118 A second domed end cap 134 is secured to the end plate 112 b and defines a chamber 135 collecting fluid from the' Openings -118 for egress through a fluid outlet conduit 136.

To assemble, the plates: 112, 112 a, 112 b and the end caps 126 and 134 are stacked in' a suitable jig with the flanges of one plate abutting the surface 122 of the next adjacent plate and the plates and end caps are suitably joined together, such' a-' by brazing' or soldering The peripheral'flanges 113 on 'the plates provide an outer shell for the 'heat exchanger so that-it'is self containedd lih use, cooling water enters the:conduit 132:and passes through the 'chamber; totlhe passages 118 (arrow-L) formed':by the flanges 119 ',at one end of:'the heat "exchanger and, exits from the opposite end into the chamber '135 and through the conduit 136 The h-ot exhaust gas, however, enters the inlet conduit 127 and into the passage' formed by the:flanges 115 (arrow M) and' fills 'the passage The gas passes through the openings 124 in'the flanges to flow between the' plates" 112 and .passes-through'the openings 125-of flanges 117 to exit -from the passage (arrow' -N) formed by the flanges 117 and from'the heat exchanger through the conduit 129 ' The gas gives upheat to the plates 112, with the slits'or 1 ouvres 123: enhancing heat trarinsfer; the heat being' transferred to the cooling water within the passages formed by flanges 119 -

Claims

WHAT WE CLAIM' IS:: 1 A heat exchanger comprising a plurality of spaced-apart similar plates joined together in a stack between two endmost plates, the plates each comprising a peripheral first flange portion, an inlet opening for a first fluid and an outlet opening for the first fluid therethrough, each opening being surrounded by second and third flange portions of the plate, and one or more passage openings through the plate for the passage of the second fluid and each surrounded by a further flange portion, all the flange portions-extending to the same height from one surface of the plate with the flanges of each flanged plate in the stack' engaging an unflanged surface of an adjacent plate, one of the endmost plates being unflanged and having no inlet and outlet openings therethrough-for the passage of the first fluid, and means being provided for permitting flow of said first fluid in the stack from the inlet openings to the outlet openings, via' the plate interspaces and means at one end of the stack for the connection of feed and return conduits for said first fluid to the 2.

1,579,276 inlet and outlet openings at that end of the stack and means at both ends of the stack for connecting the passage openings for flow of the second fluid through said passage openings from end to end of the stack.

2 A heat exchanger as claimed in claim 1, in which said plates are generally elliptical with the inlet and outlet openings positioned adjacent the ends of the plates and the passage openings located adjacent the outer edges of the plates.

3 A heat exchanger as claimed in claim 1 or 2, in which the flow of first fluid passes through said inlet opening in each of said plates and between adjacent ones of said plates to the outlet openings.

4 A heat exchanger as claimed in claim 1, 2 or 3, wherein some of said plates include a plurality of slits formed therein to enhance heat transfer from the first to the second fluid.

A heat exchanger as claimed in claim 4, in which the other endmost plate has inlet and outlet openings as well as at least one passage opening but is not provided with slits.

6 A heat exchanger as claimed in claim 5, wherein the means for permitting the first and second fluids to flow to and from the stack includes a domed end cap at each end of the heat exchanger defining a chamber therein, a fluid inlet being provided in one end cap and a fluid outlet in the opposite end cap.

7 A heat exchanger as claimed in claim 6, in which said one end cap includes inlet and outlet conduits communicating with the inlet and outlet openings in the plates.

8 A heat exchanger as claimed in any preceding claim, in which aligned flanges define the inlet and outlet openings and the passage openings and form an inlet passage for the first fluid, an outlet passage for the first fluid and passages for the second fluid, said inlet and outlet passages opening at one end of the heat exchanger, and the second fluid entering said one end of the heat exchanger and exiting from the opposite end thereof.

9 A heat exchanger as claimed in claim 8, in which the means for permitting flow in the stack between the inlet and outlet openings comprises at least one aperture formed in each of said second and third flange portions forming the inlet and outlet passages for the first fluid to allow flow of the first fluid between the inlet and outlet passages within the spacing between said plates.

A heat exchanger constructed and arranged to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.

J A KEMP & CO.

Chartered Patent Agents, 14, South Square, Gray's Inn, London WC 1 R 5 EU.

Printed in England by Her Majesty's Stationery Office, 1980 Published by the Patent Office, Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.