US3093126A

US3093126A - Engine preheater

Info

Publication number: US3093126A
Application number: US74419A
Authority: US
Inventors: David C Baker
Original assignee: Bendix Corp
Current assignee: Bendix Corp
Priority date: 1960-12-07
Filing date: 1960-12-07
Publication date: 1963-06-11
Anticipated expiration: 1980-06-11
Also published as: GB932025A

Description

June 1l, 1963 D. C. BAKER ENGINE PREHEATER 2 Sheets-Sheeil Filed Dec. 7, 1960 INVENTOR.

c. BAKER ubs/adj ATTOR `lune 11, 1963 D, c, BAKER 3,093,126

ENGINE PREHEATER Filed Dec. '7, 1960 2 Sheets-Shea?I 2 IN VEN TOR. DAVI D C. BAKER 825mm/ MQQ ATTOR EYS Uflll 3,093,126 ENGINE PREHEATER David C. Baker, Sidney, N.Y., assignor to The Bendix Corporation, Sidney, N.Y., a corporation of Delaware Filed Dec. 7, 1960, Ser. No. 74,419

9 Claims. (Cl. 12S-142.5)

'mixture Consequently, the intake air must be preheated before it is introduced to the cylinders of the engine `during the periods when the cold engine is being started.

The engine has among its objects the provision of a novel, simple and reliable preheater system for internal combustion engines.

A further object of the invention resides in the provision of a preheater system which is particularly useful with diesel engines, and may be employed to advantage with multi-fuel diesel engines.

Yet another object of the invention lies in the provision of an engine preheater system which makes use of the sources of the electrical power and fuel for the engine.

A further object of the invention lies in the provision of an improved, simplified and eflicient combustion heater unit for the preheater system of the engine.

Still another object of the invention lies in the provision of a preheater system of the type described which eliminates the necessity 'for the provision of a source of compressed air `for operatingthe combustion heater unit. The present invention is an improvement upon that States Patent disclosed and claimed in the application of David C. n

Baker, Serial No. 760,386, filed September l1, 1958, assigned to the assignee of the present application, now Patent No. 3,024,777, issued March 13, 1962.

The above and further objects and novel :features of the invention will more fully appear from the following description when the same is read in connection with the accompanying drawings. It is to be expressely understood, however, that the drawings are for the purpose of illustration only, and are not intended as a definition of the limits of the invention.

In the drawings, wherein like reference characters refer to like parts throughout the several views,

PIG. 1 is a fragmentary somewhat schematic view of an engine preheater system made in accordance with the invention, a fragmentarily shown air intake manif-old of the engine being shown partially in section;

FIG. la is an enlarged View in horizontal axial section through the control unit 15 of lFIG. 1, the switch portion of the control unit being omitted for simplicity of illustration;

FIG. 2 is a view in longitudinal axial section through the spray nozzle employed with the combustion heater unit of the system of FIG. 1;

FIG. 3 is a view in vertical transverse section through the air intake manifold of the engine immediately in advance of the combustion heater unit, the section being taken generally along the line 3-3 of FIG. 1; and

PIG. 4 is an enlarged view in end elevation of the forward end of the inner assembly of the spray nozzle.

The illustrative embodiment of preheater system includes a combustion unit 10 which is shown in FIGS.

p face of wall 27.

1 and 3. Unit 10, which will be described in detail hereinafter, provides for combustion of fuel derived from the fuel source for the engine, the products `of such combustion being discharged into the intake manifold 11 of the engine at a position between in intake air turbocompresser 12, shown schematically in FIG. 1, and the engine (not shown). Such products of combustion, mixmg with the cold air from the turbo-compresser, raise the temperature of the resulting mixture sufficiently for such gaseous mixture, when mixed with fuel injected into the cylinders of the engine, to ignite it by engine compression.

After the engine has started, the operation of unit 10 may be discontinued. Unit 10 may, however, be operated, if desired, during periods of idling of the engine. The periods of operation of unit 10 are under the control of the operator, combustion and unit 10 being initiated by ydepressing a button 14 of a control unit 15, and being stopped by releasing such button. The construction of a control ,unit 15, which governs the operathe unit being sealed to the boss by an interposed gasket,

as shown. In the embodiment shown, the preheater unit 10 is supplied with liquid fuel which may be that normally supplied to the engine, and in the case of a diesel engine may be kerosene, diesel fuel, gasoline, or that known as JP4. The preheater system shown, including the combustion unit 10, control unit 15, and a fuel pump 19, to be described, may be used without adjustment with any of such fuels. Consequently, the preheater system of the invention is particularly advantageous for use with multi-fuel diesel engines.

'Ilhe combustion preheater 10 has a hollow body 20 presenting a space 21 therewithin. Space 21 is defined by a radially disposed forward wall of body 20, by two oppositely sloping

sidewalls

22 and 24, and .by a sloping rear wall 29. As shown in FIG. 3, a spark plug 25 is threaded into an opening in wall 22; wall 24 is provvided with asimilar. threaded opening in which the spark plug may be alternatively mounted. The unused opening in the

walls

22, 24, is closed by a plug 23. A spray nozzle 26, through which the fuel to be burned in `space 21 enters, is provided with screw threads 30 by which it is mounted in a threaded opening in the rear wall 27 of body 20. After beingscrewed into such opening, the spray nozzle 26 is turned to the desired angle about its axis and is retainedk in such position by tightening a nut 34 on threads 30 into engagement with the outer ll-iuel under pressure is led to lthe spray nozzle through a pipe 31 which is connected to the rear end of the nozzle by a iitting 39. Fuel which is in excess tof that required by the nozzle is returned to the fuel supply sump by a pipe 32 lwhich is connected to the spray nozzle by a fitting 33.

sages which are angularly spaced from each other about the longitudinal axis of body 36; one 'of such passages is shown'at 40 in FIG. 2. The forward ends of passages 40 communicate with a counterbore 41 in the forward, inner end of body 36. Within counterbore 41 there is mounted an inner spray nozzle assembly 42, the assembly being connected to the body 36 by interfitting

screw threads

47 and 46 on rear portion 45 of body 44 of the inner nozzle assembly and body 36, respectively. Body 44 of the nozzle is hollow and is internally threaded as shown at 49 throughout a substantial portion of its length from its rear end. The inner spray nozzle assembly 42 has an inner body portion 50 which has an annular flange 64 intermediate its length. Flange 64 is externally threaded at 62, threads 62 being engaged with threads 49 on body 44. The rear end of body S is provided with a portion 51 of reduced diameter which is received within a counterbore 52 at the inner end of chamber 44. An annular sealing member 54, which may be made of nylon or the like, is interposed between element 51 and the counterbore 52 so as to provide a seal therebetween. It will be understood that fuel under pressure enters port 37, travels through the passages 40` and thence into chamber 41. From chamber 41 the fuel is led under pressure to the spray orifice of ythe nozzle in the following manner.

An annular sleeve-like screen 55 is disposed about the rear or inner end of the inner spray nozzle assembly. Screen 55 is retained in the position shown by an inner, screen-retaining sleeve 56, the forward end of member 56 carrying threads 57 which mate with threads 49 on body 44. The rear end of member 56 has an annular radially projecting flange 59 thereon, such flange functioning to thrust screen 55 forwardly against the rear end of portion 45 of body 44. Member -56 has one or more radial holes l60 therethrough, such holes communicating with an annular, sleeve-like space 61 between

members

56 and 50. Fuel under pressure thus travels radially inwardly through screen 55, through the one or more holes 60, and thence forwardly within space 61.

The mounting flange 64 on body 50 is provided with a plurality of longitudinally extending passages 65 therethrough so that the fuel travels from space 61 through passages 65 into a forward or inner annular chamber 66 adjacent the orifice of the spray nozzle. The nozzle has lan outer hard metal insert 67 and an inner hard metal insert 71, the two inserts having mating frusto-conical faces. In the embodiment shown, the outer insert 67 is press-fitted into a bore at the forward end of body 44, and the insert 71 has a rearwardly extending stem 75 which somewhat loosely fits within a central longitudinal opening 76 in the forward end of body S0. A gasket or washer `87 seals insert 71 to member 50 when the insert and member are thrust against each other as shown in FIG. 2. Body 67 has a frusto-conical seat 69 therein, and the forward end of insert 71 has a complementary frustoconical end surface 72. The frusto-conical surface 72 of insert 71 is provided with a plurality (four shown, FIG. 4) of narrow slots or grooves 88. Centrally inwardly of surface 72 the insert 67 is provided with a small frustoconical chamber 74, bounded by a transverse surface 78 on insert 71, the chamber 74 communicating with the central spray orifice 70 in the insert v67. It will be apparent from the above that fuel which has traveled under pressure into chamber 66 flows forwardly through the narrow slots S8 in surface 72 and thence into chamber 74 from which it is sprayed outwardly through orifice 70.

With the spray nozzle shown, the fuel which flows into chamber 74 is in excess of that which can be discharged through orifice 70. Excess fuel is led from chamber 74 of the nozzle through a flow-metering orifice and thence 'to the fuel sump. The rate of fuel flow outwardly through orifice 70, with a given viscosity of fuel, is effectively determined by the fuel pressure, the total cross sectional area of slots 88, and the cross sectional area of the return flow-metering orifice.

Insert 71 is provided with an axial passage 77 which communicates at its forward end with chamber 74 through a central passage 73. Body 50 is provided with an axially extending passage 79 which communicates with passage 77 as shown. A flow-metering insert 80, preferably made of hard metal, is disposed within a counterbore 81 in the rear end portion 51 of the body 50. Insert 80` is retained in place as by the spinning of the rear edge 83 of portion 51 over the rear edge of the insert. Insert 80 has a owmetering orifice 82 through which the excess fuel flows into a central chamber 84 in body 36. Chamber 84 is separated from inlet port 37 by an integral partition S5, as shown. The rear end of chamber 84 communicates with an outlet port 86 to which is connected the abovementioned fitting 33 to which the return pipe 32 is attached.

A short baffle 89 is disposed radially of the intake manifold 11 at the rear edge of the opening 16 thereinto. Such baffle is in the form of an L-shaped plate having an operative bafiie portion 90 extending within manifold 11 and a horizontally disposed flange portion 94 which is located in an elongated groove in the bottom of wall 27 of body 20 and is attached thereto by screws of which one is shown at 95. Portion 90 of the bafiie in the embodiment shown has two arcuate rows of

holes

91 and 92 therethrough, the outer row 91 being positioned close to the inner surface of the intake manifold, and the inner row 92 being positioned somewhat radially inwardly of the first row. `Inwardly of the holes 92 the bafiie plate 90 is imperforate. The baffle functions to prevent the direct entry of air under pressure from blower 12 into the space 21, the

holes

91 and 92 in the bafiie, however, forming a plurality of eddy currents in the air flowing across the mouth of the combustion chamber in body 20. As a result, the finally dispersed fuel issuing from spray orifice 70 is discharged into rapidly moving turbulent air so as to be thoroughly mixed therewith by the time it burns.

I'he preheater system as a whole, and its manner of operation, will be more readily understood upon consideration of FIG. 1. A fuel supply line 96, fed by gravity from a sump (not shown) has a filter 97 interposed therein. Supply line 96 leads to an inlet port 99 of the fuel pump 19. The pump, which is driven by an electric motor 110, delivers fuel under pressure from its outlet port to a supply pipe 100 which leads to an inlet port 101 of the control unit 15.

Unit 15 includes -two manually operated fluid control valves and a switch 116, the push button 14 controlling the positioning of such valves and also selectively energizing the motor of the fuel pump and a high tension ignition unit 112. Fuel under pressure is delivered from the outlet port 102 of the first valve 117 of unit l5, when the latter is open, through the pipe 31 to the abovedescribed spray nozzle 26. The fuel return pipe 312, which is connected to spray nozzle 26, is connected to a port 104 of unit 15 and thence flows through the second valve 1'19 of unit 15 and thence through port 103` and a pipe 105 to the fuel supply sump (not shown).

Control unit 1S has an elongated casing 120 which has a chamber 121 in the left-hand end thereof (FIGS. l and la). Two parallel, laterally spaced, longitudinally extending bores 122 and 124, forming parts of valves 117 and 119, respectively, extend from chamber 121 to two further,

separate chambers

125 and 126, respectively, in the right-hand end of casing `120. Inlet port 101 communicates with chamber 125, and inlet port 104 communicafes with chamber 126, as shown in FIG. la.

Reciprocably mounted in bores 122 and 124 are similar poppet valve elements 127 and 129, respectively. The right-hand end of each of elements 127 and 129 is enlarged to form a head designated 130, the head of each valve member sealingly cooperating with an annular valve seat 131 when the valve member is thrust to the left into the position shown in FIG. la by the respective spring 132. To the left of head each of valve elements 127 and 129 has a stem portion which has a diameter markedly less than that 0f bores `122 and 124. The valve elements are enlarged at the left-hand end portions within the respective bores, the enlarged portions of the valve elements accurately guidingly engaging the bores. An O-ring 134 is positioned in an annular .groove in the enlarged portion of each valve element, whereby to provide a seal between each valve element and its bore. The port 102 extends through the wall of casing 120l into communication with the portion of bore 122 confronting the reduced-diameter stem of valve element 127. The port 103 extends through the wlall of casing 120 into communication with the portion of bore 124 confronting the reduced-diameter stern of valve element 129. It will thus be lseen that when valve elements 127 and 129 are thrust to the right against the action of springs 13-2, communication is established between pipe 9'6 and port 101 and port `102, and between pipe 32 and port 104 and port 103.

The valve elements 127 .and 129 are simultaneously unseated, thereby to open valves 117 and 119, by being thrust to the right by the pressing inwardly of button 14. Button 14 is axially slidable in a central passage in an extension on casing 120. Extending axially inwardly of the casing 120 from button 14 is la rod 136 made of electrically insulating material, the inner end of Ythe rod being slidable in a bore 137 in a central member 139 integral with the casing and extending axially into the casing from the right-hand end thereof. The butt-0n 14 is constantly urged to the left toward its axially outer position by a coil compression spring 140 acting between a spring seat in member 139 and the button 14 through the medium of spacer members and a Valve actuating member.

The rod 136 is connected to button 14 by an enlarged head 141 on the rod. Telescoped over rod 136 and abutting the head 141 -thereof is an electrically conducting contact sleeve 143. A transversely disposed electrically insulating plate 144 having a central hole therein is telescoped over rod 136 and interposed between the outer end of spring 140 land the anged inner end of a sleeve 142. Sleeve 142 is interposed between contact sleeve 143 and plate 144. The left-hand ends of valve elements 127 land 129 have axial extensions 145 thereon, such extensions being slidable in holes in the outer edges lof plate 144. When the button 14 is fully retracted, as shown in FIG. la, the plate 1'44 lies spaced somewhat to the left of the shoulders 146 deiined by the junction of extensions 14'5 and the main parts of valve members 127 and 129. lt will be apparent that the button may be pushed inwardly a -short distance against the opposition of spring 140 without opening valves 117 and 119. Only when plate 144 contacts shoulders 146, upon movement of button 14 inwardly, do the valves `117 and 119l begin to open.

The switch 116 is secured to the casing 120 as shown in FIG. l. Projecting inwardly into chamber 121 of casing 120 from the housing of switch 116 are two vertically spaced generally parallel leaf spring contacts insulated from each other and constantly urged into engagement with the insulating sleeve 142 and/or the contact sleeve I143i. When the button 14 Iis retracted as shown in FIG. la, the contacts, of which the bottom contact 147 is shown in FIG. la, engage only sleeve 142, so that the circuit through the switch y116 is broken. When the button 14 is depressed somewhat, but before plate 144 engages .shoulders 146 of the valve elements, `the contact sleeve 143 completes the circuit between the leaf spring contacts, thereby energizing the fuel pump 110 and the ignition unit 112. The apparatus is thus placed in condition immediately to initiate combustion in the heater upon the -opening of valves 117 and 119! by continued inward travel of the button 14.

Power for the control system is supplied through a :suitable direct current source having ya positive terminal 106 which is connected to the switch 116 by a wire 107. The live side of the circuit issues from the switch 1.16 and is branched so that one supply wire 109 extends to fuel pump motor 110 and another supply wire 111 ex- 6 tends to ignition unit 112. The ignition unit, which supplies a succession of high voltage discharge pulses when it is energized, -is connected to spark plug 25 of the preheater through a high tension shielded lead 114.

An engine provided with the above-described preheater system is started as follows: The engine is turned over by means of the engine starter. While the engine is turning over, the switch 116 is closed by the pushing of button 14 to cause spark discharges to occur at the spank plug 25. Simultaneously therewith, the pushing of button 14 opens valves 117 and 1119 so that fuel is led under pressure to the spray nozzle 26 and is discharged therefrom in the form of a spray through orifice 70, excess fuel being returned through valve 119. The turbo-blower 12 will, of course, have been started before or at least simultaneously with the closing of switch 116. The mixture of dispersed fuel with air in the manifold 11 will ignite upon reaching the spark gap of the spark plug 25. The products of combustion from chamber Z1 enter the mani-fold 11 to mix with the air from the turbo-compressor 12 and thus to raise the temperature of the air drawn into the engine. The volume of such products of combustion relative to the air provided by the turbo-compressor is insufficient -to prevent operation of the engine in a normal manner. After engine ignition has taken place, button 14 is released, thereby closing the fuel valves 117 and 119 in unit 15, and opening switch 116 to deenergize the fuel pump motor and to deenergize the ignition unit 112.

Although only one embodiment of the invention has been illustrated in the accompanying drawings 'and described in the foregoing specification, it is to be especially understood that various changes, such as in the relative dimensions of the parts, materials used, and the like, as well as the suggested manner of use of the apparatus of the invention, may be made therein without departing from the spirit and scope of the invention as will now be apparent to those skilled in the art.

What is claimed is:

l. An engine intake air preheater unit comprising a combustion chamber-forming housing having an open inner delivery end and a closed outer end, the inner end of the housing being adapted for attachment to an air inlet conduit of an internal combustion engine at an opening in said conduit, 'a lliquid fuel spray nozzle mounted on the Wall of the housing for discharging fuel in comminuted form within the combustion chamber, the spray nozzle being -inclined downwardly and forwardly in the direction of air flow to the engine so -as to discharge its spray generally forwardly -and through the opening in the conduit toward the axis of the conduit, and a spark discharge means disposed within the housing forwardly of the spray nozzle and in the path of fuel issuing from the nozzle.

2. A preheater unit as claimed in claim l, comprising a baffle having a plate adapted to project transversely within the conduit at the rear of the opening in the conduit, said plate extending a substantial distance radially into the conduit, the plate having a plurality of spaced holes therethrough near the wlall of the conduit adjacent the inner surface of the conduit.

3. A preheater unit as claimed in claim l, wherein the spray nozzle is of the solid spray type, and comprising a source of fuel, means to supply the spray nozzle from said source with an excess of fuel under pressure, 'and means to return the excess fuel to the fuel source.

4. In an internal combustion engine having an air inlet conduit, the improvement which comprises an engine intake air preheater unit comprising a combustion chamber-forming housing having an open inner delivery end and a closed outer end, the inner end of the housing being attached to an air inlet conduit of the engine at an opening in said conduit, the inner surface of the rear wall of the housing being inclined in a direction forwardly and radially outwardly of the conduit, a liquid fuel spray nozzle mounted on the rear wa'll of the housing with its axis generally normal to the inner surface of such rear wall so las to discharge its spray generally forwardly in the direction of air ilow to the engine and toward the axis of the inlet conduit and partially within the combustion chamber .and partially directly into the conduit, and a spark discharge means disposed within the housing forwardly of the spray nozzle.

5. Apparatus as claimed in claim 4, comprising a braille having a plate adapted to project transversely within the conduit at the rear `of the opening in the conduit, said plate extending a substantial distance radially into the conduit, the plate having la plurality of spaced holes therethrough near the wall of the conduit adjacent the inner surface of the conduit and aligned with the portion of the spray from the nozzle which penetrates directly into the conduit.

6. A preheater unit as claimed in claim 5, wherein the baille is secured to the housing.

7. Apparatus as claimed in claim 6, wherein the baille is L-shaped in end elevation and has a second plate portion disposed generally at right angles to the lrst recited plate, the second plate underlying and being secured to the rear edge of the housing at the open inner end thereof.

8. In an internal combustion engine having an air in- `let conduit, the improvement which comprises an intake air preheater system for the engine, said system comprising an engine fuel-burning preheater unit having a combustion chamber and a spark ignition device within such chamber, said preheater unit being attached to the conduit to discharge heated -gas thereinto through an Opening in the conduit between the air inlet end thereof and the c; engine, a solid injection liquid fuel spray nozzle mounted on the preheater unit so as to discharge fuel in comrninuted form within the combustion chamber, the spray nozzle being disposed at such yangle with respect to the conduit as to discharge its spray generally forwardly in the direction of air llow to the engine and toward the axis of the inlet conduit and partially within the combustion chamber and partially directly into the conduit, a source of fuel supply, means to supply liquid fuel under pressure to the spray nozzle, and means to return excess fuel from the nozzle to said source.

9. Apparatus as claimed in claim 8, comprising a baille having a plate adapted to project transversely within the conduit at the rear of the opening in the conduit, said plate extending a substantial distance radially into the conduit, the plate having a plurality of spaced holes therethrough near the wall of the conduit adjacent the inner surface of the conduit and aligned with the portion of the spray from the nozzle which penetrates directly into the conduit.

References Cited in the file of this patent UNITED STATES PATENTS 1,379,178 Good May 24, 1921 1,395,399 Doble et al. Nov. 1, 1921 1,473,136 Woolson Nov. 6, 1923 1,613,000 Widdowson Jan. 4, 1927 1,733,792 Good Oct. 29, 1929 FOREIGN PATENTS 801,774 Great Britain Sept. 24, 1958

Claims

1. AN ENGINE INTAKE AIR PREHEATER UNIT COMPRISING A COMBUSTION CHAMBER-FORMING HOUSING HAVING AN OPEN INNER DELIVERY END AND A CLOSED OUTER END, THE INNER END OF THE HOUSING BEING ADAPTED FOR ATTACHMENT TO AN AIR INLET CONDUIT OF AN INTERNAL COMBUSTION ENGINE AT AN OPENING IN SAID CONDUIT, A LIQUID FUEL SPRAY NOZZLE MOUNTED ON THE WALL OF THE HOUSING FOR DISCHARGING FUEL IN COMMINUTED FORM WITHIN THE COMBUSTION CHAMBER, THE SPRAY NOZZLE BEING INCLINED DOWNWARDLY AND FORWARDLY IN THE DIRECTION OF AIR FLOW TO THE ENGINE SO AS TO DISCHARGE ITS SPRAY GENERALLY FORWARDLY AND THROUGH THE OPENING IN THE CONDUIT TOWARD THE AXIS OF THE CONDUIT, AND A SPARK DISCHARGE MEANS DISPOSED WITHIN THE HOUSING FORWARDLY OF THE SPRAY NOZZLE AND IN THE PATH OF FUEL ISSUING FROM THE NOZZLE.