US3835822A

US3835822A - Cooled fuel pump for internal combustion engines

Info

Publication number: US3835822A
Application number: US00281037A
Authority: US
Inventors: J Mickle; N Horn
Original assignee: Brunswick Corp
Current assignee: Brunswick Corp
Priority date: 1972-08-16
Filing date: 1972-08-16
Publication date: 1974-09-17
Anticipated expiration: 1991-09-17

Abstract

A fuel pump for water-cooled marine engines includes a cast aluminum housing. A water cooling tube is embedded in the housing connected directly to the inlet of the main cooling system for the engine such that upon initial starting of the engine, cooling water is immediately supplied to the fuel pump to reduce its temperature, and thereby eliminate vapor lock conditions. The tube may be formed of suitable material to minimize electrolytic conditions with respect to the cast housing and prevent possible leakage of water into the fuel system.

Description

United States Patent [1 1 Mickle et al.

[ COOLED FUEL PUMP FOR INTERNAL COMBUSTION ENGINES [75] Inventors: John L. Mickle; Norman E. Horn,

both of Oshkosh, Wis.

[73] Assignee: Brunswick Corporation, Chicago,

221 Filed: Aug. 16,1972

21 Appl. No.: 281,037

[52] US. CL... [ZS/41.31, 123/139 A, 123/139 AH, 123/138 AN, 417/364, 417/372 [51] Int. Cl. F0lp 11/00 [58] Field of Search 123/4131, 122 E, 139 A, 123/139 AH, 139 AN, 195 P, 41.8; 417/364,

[56] References Cited UNITED STATES PATENTS 10/1943 lrgens 123/4l.8 7/1955 Armstrong et al. 123/139 AH Sept. 17, 1974 2,791,186 5/1957 Alden 123/4131 X 2,835,239 5/1958 Dickrell 123/139 AH 3,314,882 3/1969 lrgcns 123/195 P Primary ExaminerCharles J. Myhre Assistant ExaminerDaniel J. OConnor Attorney, Agent, or Firm-Andrus, Sceales, Starke & Sawall 5 7 ABSTRACT A fuel pump for water-cooled marine engines includes a cast aluminum housing. A water cooling tube is embedded in the housing connected directly to the inlet of the main cooling system for the engine such that upon initial starting of the engine, cooling water is immediately supplied to the fuel pump to reduce its temperature, and thereby eliminate vapor lock conditions. The tube may be formed of suitable material to minimize electrolytic conditions with respect to the cast housing and prevent possible leakage of water into the fuel system.

9 Claims, 5 Drawing Figures COOLED FUEL PUMP FOR INTERNAL COMBUSTION ENGINES BACKGROUND OF THE INVENTION The present invention is particularly directed to a fuel pump for internal combustion engines, particularly watercooled marine engines.

Marine propulsion devices and the like employing internal combustion engines are generally water-cooled. In outboard motors, when the engine is stopped, block temperature increases significantly as the water is allowed to drain from the internal combustion engine. The engine of an outboard motor and the like is also normally enclosed within a suitable decorative and protective enclosure, which, of course, contributes to a high heat condition surrounding the engine particularly upon stopping. The engine fuel pump is mounted to the engine within the enclosure and coupled to the operating components for synchronous and proper delivery of fuel to the carburetor means. As a result, the ambient and the block temperature which rises very significantly may, in fact, generate vapor lock conditions in the fuel system. In order to eliminate the adverse conditions resulting from the high temperatures and particularly those associated with the stopping of the engine or the like, the fuel pump and associated components have been mounted in spaced relation to the engine block and coupled thereto through a suitable coupling means. It is advantageous, however, to permit direct mounting to the side of the block with appropriate block openings providing connection to the pump mechanism. This s particularly true in diaphragm-type actuated pumps where the pressure conditions in the crankcase and cylinder units can be employed to create a pumping action. For example, vacuum pumping systems are known wherein a vacuum pump is mounted in abutting relation to the crankcase block, with appropriate openings from the crankcase block to a diaphragm pumping chamber. The diaphragm is moved in synchronism with crankcase pressure which varies between a high and a low level and results in a pumping action. Normally, a vacuum is created on the fuel tank side to draw the fuel from the tank into the pump and then a positive pressure is created to transfer the fuel to carburetor. However, with such structure, the heat conditions are such that vapor lock conditions can arise with adverse operating characteristcs; for example, inadequate propulsion forces upon initial shifting and starting acceleration of the boat, if not complete stallmg.

SUMMARY OF THE PRESENT INVENTION The present invention is particularly directed to an improved fuel pump for water-cooled marine engines and the like which are particularly subject to at least temporary adverse temperature conditions. Generally, in accordance with the present invention, the fuel pump is provided with a special water cooling passageway which is connected to provide for cooling of the fuel in synchronism with the operation of the engine and to thereby ensure the transmission and supply of essentially cool fuel from the pump to the engine firing means. In accordance with one aspect of the present invention, the water cooling system is connected directly into the main water cooling system such that upon initial starting of the engine, cooling water is immediately supplied to the fuel pump to reduce its temperature, and thereby eliminate vapor lock conditions. In accordance with a particularly novel aspect of the invention to produce optimum conditions, the fuel pump cooling system is connected in line with the inlet side of the cooling water supplied to the engine to supply the coldest available water to the fuel pump, particularly at the initial starting. Applicants have found that this system allows a direct mounting of the fuel pump to the engine without the necessity of any special mounting systems or spacing of the fuel pump from the engine block or the like.

The cooling system should be constructed to prevent the passage of any water from the water passageway into the fuel which would, of course, result in highly adverse engine operation. In accordance with a further important and novel aspect of the present invention, the water-cooling passageway is formed from a waterimpervious tubing such as a brass tube which is cast within the body portion of the fuel pump. This ensures complete isolation of the water which can pass through the normal cast aluminum fuel pump and thereby permits the use of conventional aluminum alloy casting and the like.

The present invention provides a simple and inexpensive system for significantly improving the operating characteristic of a marine propulsion engine device and particularly during the initial movement of the boat means.

BRIEF DESCRIPTION OF DRAWING The drawing furnished herewith illustrates a preferred construction of the present invention in which the above advantages and features are clearly disclosed as well as others which will be readily understood from the subsequent description of such embodiment.

In the drawing:

FIG. 1 is a diagrammatic illustration of the power head of an outboard motor with a fuel pump construction in accordance with the present invention mounted thereon;

FIG. 2 is an enlarged diagrammatic vertical section through a portion of the engine and the fuel pump;

FIG. 3 is a vertical section through a fuel pump showing the pump chamber housing;

FIG. 4 is a sectional view taken generally on line 4-4 of FIG. 3; and

FIG. 5 is a view taken generally on line 5-5 of FIG. 4.

DESCRIPTION OF ILLUSTRATED EMBODIMENT Referring to the drawing and particularly to FIG. 1, an internal combustion engine 1 is shown forming a part of the power head of an outboard motor and in particular mounted upon the upper end of a lower drive unit 2 of which only a fragmentary portion is shown. A protective cowl or enclosure 3 is mounted upon the lower unit 2 and encloses the engine 1 and associated starting components and the like. The cowl 3 is shown with parts broken away to expose a pair of fuel pumps 5 which illustrated an embodiment of the invention. In accordance with conventional constructions the internal combustion engine is coupled through any wellknown desired drive means to drive a propeller propulsion mechanism mounted at the lowermost end of the lower unit 2. The illustrated engine 1 is a four cylinder type with the pair of fuel pumps 5 mounted to the side of the engine block 6 of the engine 1 to locate each fuel pump at the junction of a pair of cylinder units. The fuel pumps 5 are connected in parallel to draw gas from a fuel tank 7 and supply the fuel via a common carburetor filter unit to the carburetor 7a. The engine 1 is provided with a water cooling jacket, not shown, with a water pump 8 mounted within the lower unit 2 and drawing water upwardly directed from the water within which the marine propulsion unit is operating. The water passes upwardly through an inlet tube 9 to and through the engine block 6 and is discharged downwardly through the exhaust passageway within the lower unit 2. In accordance with the present invention, the fuel pumps 5 are also water cooled. In particular, each of the illustrated fuel pumps 5 is provided with a water passageway tube 10 passing through the pump 5 and connected in circuit with the cooling system of pump 8 for the internal combustion engine. In particular, in the illustrated embodiment of the invention, the pumps 5, as shown in FIG. 1, have the inlet ends of the passageway tubes 10 connected to a water supply line or hose 11 which is connected to the inlet side of the engine block cooling chamber or passageway by a suitable coupling 12. A hose 13 interconnects the outlet sides of the fuel pumps 5 to a water discharge coupling 14 to the outlet side of the engine for passage through the water cooling exhaust system of the engine 1 and discharge through the conventional exhaust passageway.

In the operation of the outboard motor, the initial cranking of the engine 1 results in corresponding actuation of the water pump 8 to provide immediate cooling water into the engine block and simultaneously to the fuel pumps 5. Further, by connection to the inlet side of the engine water cooling system, the coldest available water is supplied to the fuel pumps 5 to rapidly reduce the temperature of the pump and fuel. It is found that in a practical construction of the internal combustion engine for an outboard motor unit, the temperature of the fuel can be reduced in the order of 26 to 36F. in the time usually taken to start the engine and shift from neutral to a forward or reverse position, with a fuel pump such as shown in FIGS. 2-5. The cooled gas also tends to cool the carburetor 7a and thereby promote efficient transfer of fuel to the engine for establishing optimum ignition conditions particularly during the initial starting of the engine. In particular, applicants have found that the present invention eliminates the vapor lock condition which has been encountered with prior art structures and permits rapid and efficient operation of the outboard motor unit.

Each of the fuel pumps 5 is similarly constructed and the construction of one of the units is more clearly shown in F I68. 2 5 and described as follows. The preferred construction as shown in FIGS. 2 5 includes a conventional diaphragm-actuated vacuum pump unit which is mounted in abutting relation directly to the engine block 6 for operation by the crankcase pressures. In particular, the illustrated fuel pump 5 is a generally known diaphragm vacuum operated type having a twopiece housing including an outer fuel pump cover 16 and an inner diaphragm cover 17 interconnected in opposed abutting relation, with a flexible diaphragm l8 clamped therebetween. The fuel pump 5 is secured directed in abuttment to the engine block 6 by a pair of attachment screws 19 which pass through appropriate openings in the housing sections and into suitable tapped openings in the engine block 6. The fuel pump 5 is constructed with a. main pumping chamber 20 and a booster chamber 21 in the pump cover 16 with corresponding separate input chambers 22 in the diaphragm cover 17 aligned therewith. The pump 5 is mounted to the engine 1 adjacent to the intermediate wall of adjacent crankcase and the diaphragm section or cover 17 includes a pair of spaced openings 23 and 24 coupled respectively with corresponding openings in the engine block to the adjacent crankcases 25 and 26. The adjacent crankcases 25 and 26 have opposite crankcase pressures which alternate with-the associated pistons. The main pumping chamber 20 includes an inlet check valve 27 connected to the fuel tank line 28 and an outlet check valve 29 connected to the carburetor connection line 30 and also to the secondary or booster pressure chamber 21.

The check valves 27 and 29 are conventional springloaded valve units mounted in the base wall of the main pumping chamber 20, with suitable interconnecting passageways providing connection to the fuel inlet line 28 and the discharge line 30 as well as the secondary pumping chamber. Consequently, no further description thereof is given.

As the engine alternates the pressure in the crankcase, the inlet and outlet check valves 27 and 29 open and close to draw fuel into the main pumping chamber 20 and pass it to the carburetor with the secondary chamber 21 increasing pressure at the discharge line 30, in accordance with well-known constructions.

In accordance with the illustrated embodiment of the present invention, the cooling water passageway is formed by the tube 10 and as a generally U-shaped passageway which is integrally cast into the outer housing or the pump cover 16. The base portion of the passageway 10 is looped about and in close spacing to the main pumping chamber 20, and as most clearly shown in FIGS. 3 and 5, provides continuous cooling water flow over the chamber wall to establish and maintain a rapid and efficient cooling of the fuel within the fuel pump during operation of the engine 1. The booster chamber 21 is located to one side of the main chamber 20, as most clearly shown in FIG. 4, with the cooling passageway 10 also adjacent a portion of its wall. The cooling water is thus positioned in relatively close coupling to the

fuel chambers

20 and 21 to efficiently cool the gas. The cooling passageway means may be located in any desired manner but is preferably located to produce maximum cooling.

In accordance with an important aspect of the present invention, the cooling passageway is defined by the separate tube 10 formed of a suitable material which is impervious to the cooling water such that there is no danger of any transfer of the cooling water from the passageway through the walls thereof into the fuel pump housing. The fuel pump housing 16 may then be formed of cast aluminum and the like which is porous and may readily transmit water. Thus, if the passageway were directly formed within such a cast body, water would eventually leak into the fuel pump resulting in malfunctioning of the engine.

Further, the separate tube member 10 may be formed of a suitable material which does not create suf ficient electrolytic action with the cast body of the fuel pump to cause danger of excessive corrosion which could result in perforation of the tube and the transfer of water. This becomes very significant in connection with outboard marine equipment and the like.

Further, the tube should form a good heat transfer joint with the housing. Applicants have found that a brass tube adheres to the casting and produces good thermal conductivity without the necessity of any intermediate adhesive or filler.

The passageway can of course be shaped in any desired manner and could include one or more passageways as required or desired. Applicants have found that the simple U-shaped tube, integrally cast about the main chamber and with the base portion adjacent to the secondary chamber provides a very satisfactory and relatively inexpensive construction which provides the desired reduction in temperature of the fuel and at a sufficiently rapid rate to prevent vapor lock conditions under all normal and anticipated operating conditions.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims, particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

We claim:

1. In combination, an internal combustion engine having an engine block and an engine cooling passageway means and a cooling pump means having an outlet means connected to supply a cooling liquid through the passageway means, a fuel pump having an outer housing defining an internal pumping chamber with a confining wall portion, a fuel pump cooling passageway in said wall portion having an impervious confining wall surface and including an inlet means and an outlet means, said outlet means being connected to said engine cooling passageway means, and means connecting the inlet means of said pump cooling passageway to the outlet of the cooling pump means and producing a continuous flow of cold cooling liquid through said passageway to reduce the temperature of the fuel.

2. The fuel pump of claim 1 wherein said fuel pump includes a cast metal body, said fuel pump cooling passageway including a tubular member cast within said cast metal body and formed of a material nonelectrolytic with respect to the cast metal body and thereby preventing electrolytic action and perforation of the tubular member.

3. The engine of claim 1 wherein said fuel pump includes a cast aluminum body, said fuel pump cooling passageway including a brass tubular member integrally cast within said cast aluminum body.

4. The engine of claim 3 wherein said fuel pump includes a pump body with a main pumping chamber defined by a generally oval recess and a secondary pumping chamber located to one side and immediately adjacent to said main pumping chamber, said fuel pump passageway being formed as a generally U-shaped member extending about the main pumping chamber and with the portion of the passageway located in the wall portion adjacent to the secondary pumping chamber.

5. The fuel pump of claim 1 wherein said fuel pump includes a pump body with a main pumping chamber defined by a generally oval recess and a secondary pumping chamber located to one side and immediately adjacent to said main pumping chamber, said fuel pump passageway being formed as a generally U- shaped member extending about the main pumping chamber and with the portion of the passageway located in the wall portion adjacent to the secondary pumping chamber.

6. The fuel pump of claim 5 wherein said fuel pump passageway is lined with a preformed tubular member formed of a metal which is impervious to water and which minimizes electrolytic action with respect to the body of the fuel pump.

7. An internal combustion engine forming a part of a marine propulsion unit and having an engine block and a water cooling system means to continuously supply water from the body of water in which the engine is operating to an engine cooling passageway means in the engine block for cooling and including a fuel pump, said fuel pump comprising means for mounting the fuel pump to the engine block and including pressure activating opening means coupled to at least one crankcase unit of the internal combustion engine, a water passageway means in said fuel pump located in efficient heat exchange relationship to said fuel passageways, and means connecting said water passageway means with the inlet side of the cooling passageway means for supplying cooling water to flow through said fuel pump and in series with said cooling passageway means and to thereby create a series flow of cooling liquid through the fuel pump and then the engine cooling passageway means to provide synchronism with the cooling of the engine.

8. The engine of claim 7 wherein said engine cooling passageway means and said water passageway means are constructed to automatically drain the water therein upon termination of the operation of the engine.

9. The method of providing fuel to a fuel pump an internal combustion engine forming a part of a marine propulsion device wherein water cooling is provided to the internal combustion engine by drawing water upwardly from the supporting body of water and passing it through the engine and discharging it therefrom, said water cooling passageway means being constructed to provide for automatic draining of the water from the engine upon turnoff upon stopping of the engine, comprising the steps of providing water cooling to said fuel pump in synchronism with the provision of cooling water to said engine, and correspondingly draining of the cooling water from the engine and from said fuel pump upon termination of the operation of the engine.

and that said Letters Patent are hereby corrected as shown below:

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,835,822 Deted September 17, 1974 Inventor(s) JOHN L. MICKLE and NORMAN E. HORN It is certified that error appears in the a boveridentified pat ent v Column 6, Line 43, after "pump" insert CLAIM 9 si nedand, -aliedthis are day of'Decexfiber 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. Attesting Officer C. MARSHALL DANN Commissioner of Patents ORM USCOMM-DC 60376-P69 U.5. GOVERNMENT HUNTING OFFICE IO! 0-866-334,

Claims

2. The fuel pump of claim 1 wherein said fuel pump includes a cast metal body, said fuel pump cooling passageway including a tubular member cast within said cast metal body and formed of a material non-electrolytic with respect to the cast metal body and thereby preventing electrolytic action and perforation of the tubular member.

5. The fuel pump of claim 1 wherein said fuel pump includes a pump body with a main pumping chamber defined by a generally oval recess and a secondary pumping chamber located to one side and immediately adjacent to said main pumping chamber, said fuel pump passageway being formed as a generally U-shaped member extending about the main pumping chamber and with the portion of the passageway located in the wall portion adjacent to the secondary pumping chamber.