US3507262A - Fuel injection system - Google Patents

Description

J. W. STAGE FUEL INJECTION SYSTEM April 21, 1970 Filed Feb. 29. 1968 INVENTOR JACK #4. STAGE [WWW AT OR/VEYS 2 Sheets-Sheet April 21, 1970 J. w. STAGE 3,507,262

FUEL INJECTION SYSTEM Filed Feb. 29, 1968 2 Sheets-Sheet 2 /92 zga L FUEL INVENTOR JACK l4. STAGE ATT RNEYS United States Patent 3,507,262 FUEL INJECTION SYSTEM Jack W. Stage, 100 Mount Lyell Drive, San Rafael, Calif. 94903 Filed Feb. 29, 1968, Ser. No. 709,285 Int. Cl. F02m 33/00; F02d 1/04; F04b 1/14 US. Cl. 123-139 8 Claims ABSTRACT OF THE DISCLOSURE A fuel injection system for minutely controlling amounts of fuel injected into the cylinders of an internal combustion engine while inhibiting the formation of gas in the fuel between the fuel pump and the injector nozzle including a pump having elongated pumping chambers of hollow circular cross section, a fuel line pressure maintainer, and an injector-igniter unit having a long slender tapered valve pin reciprocatingly seated in a metallic noule plug. i

This invention relates generally to a fuel injection system for an automotive engine and more particularly relates to improved means for pumping and injecting unoccluded fuel to an engine cylinder.

In a fuel injection system and more particularly those wherein an injector unit is responsive to fuel pressure, it is necessary to prevent the formation of gas between the injector pump and the injector unit. By gas it is meant the bubbles of flashed fuel which are generated principally by heat and vacuum, although it may mean any pressure-absorbing occlusion. It is a fact that the operation of internal combustion engines at increasingly higher temperatures enhances the conditions wherein gas may be formed. Since it is true that a reduction of fuel pressure reduces the temperature at which the fuel boils, one of the major problems of the prior art fuel injection systems has been the formation of gas caused by the utilization of injection pumps which subject fuel to a negative pressure on the piston downstroke. Another problem in the prior art fuel injection systems has been the formation of gas caused by the utilization of fuel injection units or nozzles which store fuel closely adjacent to the combustion chamber of the engine cylinder prior to injection to thus subject the fuel to extremely high temperatures. The creation of gas by the incorporation of the above features in the prior art systems results in an inefficient and many times inoperative system since a gas bubble in the fuel line acts as a pressure absorber which destroys the pressure transmission characteristics by which a true hydraulic system is operated and upon which selection of a uniform amount of fuel to be injected is predicated. It is a primary object of this invention, therefore, to provide a fuel injection system which diminishes the problems of the prior art by means which inhibit the formation of gas.

Another important object of the invention is to provide a fuel injection system having in combination an injector pump, a line pressure unit and an injector ignition unit working together to inhibit the formation of gas.

A further object of the invention is to provide a fuel injection system for an internal combustion engine in cluding a variable stroke fuel injection pump for minutely controlling the amount of fuel pumped by means of a reciprocating pumping ring operating in an elongated pumping chamber having a hollow circular cross section.

A still further object of the invention is to provide a fuel injection system including an injector-igniter unit which receives and stores fuel at a point substantially removed from the engine cylinder prior to injection therein.

3,507,262 Patented Apr. 21, 1970 These and other objects of the invention will become more apparent to those skilled in the art by reference to the following detailed description when viewed in light of the accompanying drawings wherein:

' FIGURE 1 is a cross sectional view of the major components of the fuel injection system;

FIGURE 2 is a perspective view of the fuel pump cam plate; 1

FIGURE 3 is a perspective view of the hot mix adjuster;

FIGURE 4 is a perspective view of the adjusting sleeve for the hot mix adjuster; 1

FIGURE 5 is a detailed cross sectional View of a selected portion of the injector-igniter unit; and

FIGURE 6 is a cross sectional view taken along line 66 in FIGURE 5.

Referring now to the drawings wherein like numerals indicate like parts, the numeral '10 indicates the fuel injection system of this invention. The system is adaptable for use on conventional automobile internal combustion en gines and requires no engine modifications other than the provision of a drive shaft 12 which can be a takeoff from the distributor shaft. The major cooperating elements of the system include a fuel injection pump 14, a line pressure maintainer 16 and an injector-igniter unit 18, all connected together by a fuel line 20. It is the cooperation of these elements which results in a fuel injection system wherein exact amounts of fuel are injected in each cylinder to cause complete burning and to thereby eliminate the need for smog control devices as well as to increase mileage per gallon.

The fuel injection pump 12 is structured so that it is mass-producible at a low cost and yet functions with extreme efiiciency and precision in pumping closely controlled minute amounts of fuel into the fuel line 20. It is Within the capability of the pump to automatically vary its stroke in response to acceleration changes, temperature changes, and pressure changes as well as to be separately manually adjustable in order to vary the leanness of the air-fuel mixture in the engine cylinders.

Referring to the drawings, the pump 14 is a multiplecylinder, fuel-injection pump comprised of a cast body portion or member 22 having its lower periphery received in and secured to a cylindrical casing 24 by a plurality of bolts 26. A drive shaft '12 projects through an axial opening 27 in the bottom of the casing and is rotatably received therein by means of a bearing 28. A space 29 is provided between the bearing 28 and a casing flange 30 in order to receive a shaft collar 31. The shaft collar prevents relative longitudinal movement between the pump and the drive shaft.

The body member 22 has an enlarged central fuel chamber 32 which is located above the upper end of the drive shaft 12 and which is divided into upper and lower chambers 38 and 40, respectively, by an inwardly directed annular ridge 41. The ridge has an undersurface 43 which tapers inwardly and upwardly in order to promote fuel distribution as well as to aid in the segregation of any gas bubbles by guiding them into the upper chamber where they will do no harm. A supply inlet 44 located in the upper chamber wall provides fuel from a fuel source such as the fuel tank of an automobile.

Surrounding the fuel chamber 32 are a plurality of parallel,.circumferentially spaced bores 34 in which rods 36 are arranged to reciprocate. A single bore is, of course, provided for each engine cylinder.

Since the pump cylinders 34 are open at both ends and represent a continuous boring through the body 22, seals '48 and 50 are located in the walls of the cylinder 24 adjacent the upper and lower ends thereof, respectively, in order to sealingly engage the rod 36. The seals are held in place by removable screw plugs 52 which have central openings large enough to permit passage therethrough by the appropriate portions of the rod 36. The top of the rod 36 is thus open to the atmosphere and, in order to protect it from dust and debris, a cylindrical cap 76 having an air filter 78 is provided on the upper plug 52.

It is important to note that the rod 36 is of lesser diameter than the cylinder 34 and that the seals 48 and 50 project peripherally inwardly to bear against the outer surface of the rod 36. The actual pumping chamber is thus formed by the peripheral space between the rod 36 and the cylinder 34 between the seals 48 and 50 and has a cross sectional area of a hollow circle. In order to pressurize fluid in the elongated pump chamber, a piston ring 54 is provided on the rod 36. The piston ring is particularly located longitudinally on the rod 36 in order to cooperate with the various passageways communicating with the fuel chamber 32 and extend outwardly from the rod 36 into sliding sealing contact with the walls of the cylinder 34.

Fuel is supplied to the pump chamber by means of an inlet port 56 at the upper end of each cylinder located just below the upper seal 48. The inlet port is connected to the lower fuel chamber 40 by means of a vertically disposed check valve 58 in the ridge 41 which has a ball 60 biased to the closed position by spring 62. Located substantially diametrically opposite the inlet port 56 is an outlet port 64 connected to the fuel line 20 and having a check valve 66 with a ball 68 normally biased by spring 70 to the closed position. Spaced approximately midway between the upper and lower seals 48 and 50 in the wall of the cylinder 34 is a metering orifice 72 which extends downwardly at an angle from the cylinder wall to the lower fuel chamber 40. A relief orifice 74 is located below the metering orifice 72 and is adjacent the lower seal 50 to extend between the lower chamber 40 and cylinder 34.

As can be seen from the drawings, when the rod 36 is on the down stroke, sufficient suction is created to draw fuel from the fuel chamber 70 past the check valve 58 of the inlet port 56 until the piston ring 54 descends below the metering orifice 72. Upon passing downwardly beyond the orifice 72, fuel will enter the pump chamber through both the inlet port and the said metering orifice. Any fuel located between the piston ring 54 and the lower seal 50 is expelled therefrom into the lower fuel chamber 40 4 through the relief orifice 74. On the upstroke of the rod 36 fuel will egress from the pump chamber back into the lower fuel chamber 40 through the metering orifice 72 until the piston ring 54 ascends beyond it. The amount of longitudinal travel beyond the metering orifice 72 toward the upper seal 38 determines the effective stroke of the pump since it is easily seen that operation of the piston ring 54 upwardly above the metering orifice 72 will cause the fuel to be pumped outwardly through the outlet port 64 to the fuel line 20.

The lower end of the rod 36 extends below the body member 22 and terminates at its end in a fork 80 having inner and outer downwardly depending legs 82 and 84, respectively, between which a roller bearing 86 is rotatably supported about a shaft 88. The shaft 88 is secured at each end to the legs 82 and 84.

As can be seen in the drawings, the roller bearing 86 is biased against a circular cam plate 90 which is slidably received on splines 94 on the upper end of the shaft 12 for rotation therewith. The cam plate is provided with an upstanding lobe 96 on its outer periphery which bears against the roller bearing 86 to periodically reciprocate the rod 36. A coil spring 98 surrounds the rod 36 between the upper shoulder of the fork 80 and the bottom of the body member 22 in order to bias the rod toward the cam plate 90.

In order to vary the etfective stroke of the rod, the cam plate is vertically adjustable relative to the body member 22 and the shaft 12 by two separately adjustable collar means. The first adjusting means to be discussed is a hot mix adjuster collar 100 which surrounds the drive shaft 12 but is stationary in relation to the housing 24. Provision in the hot mix collar 100 of an outwardly projecting radial arm 102 which extends through a vertical slot 104 in the casing 24 provides a manually adjustable means for varying the vertical position of the hot mix adjuster collar and the cam plate 90. In order to facilitate movement of the arm 102, a sleeve 108 is rotatably disposed about the casing 24 and has a diagonal slot 106 within which is received the end of the arm 102. The sleeve 108 is pivotally secured about the casing 24 by means of screws 109 which pass through a pair of horizontal slots 111 so that by simply turning the sleeve 108 a desirable increment, the sides of the slot 106 will bear against the arm to move it in the desired vertical direction.

The second adjusting means for varying the effective stroke of the rod 36 is an auto-adjust collar which surrounds and is supported by the hot mix collar 100 within the casing 24. The collar 110 has a flange 112 which encompasses the upper portion of the collar 100 and which depends downwardly substantially centrally from a circular plate portion 113. The upper outer peripheral surface of the plate 113 is provided with a bearing race 114 in which are located ball bearings 115 for supporting the rotatable cam plate 90. The auto-adjust collar 110 is itself supported by the hot mix collar 100 by provision of a nib 116 which projects inwardly from the lower portion of the inner surface of the depending flange 112 and which fits into a diagonal or helical groove 118 provided within the outer surface of the hot mix collar 100. A control arm 120 projecting radially outwardly from the auto-adjust collar 110 through a slot 122 in the casing 24 is adapted for automatically pivoted movement about the longitudinal axis of the auto-adjust collar 110 by an environmental sensing means 124. The sensing means 124 can be a pressure or temperature-responsive device well known to those skilled in the art.

It must be emphasized that the high degree of control and adjustability over the small amounts of fuel being pumped out of each pump cylinder is the result of the structural features of the pump itself. By utilizing the annular piston ring 54 as the pump means, the pump chamber assumes the shape of an elongated cylindrical shell whose volume can be minutely controlled. Coupled with this, is the fact that the metering orifice 72 enters the cylinder at an angle upwardly from the fuel chamber 32 so that the opening in the wall of the cylinder has a substantially elliptical shape rather than being circular. The elliptical opening has a vertical major axis whose upper periphery is more finely tapering than that of a circle for less turbulence and more finely controlled metering into the pump chamber.

Once the power stroke of the rod 36 is completed, the following downward stroke has little or no elfect upon the fuel which has been expelled into the line 20. This is due to the fact that the check valve 66 isolates the fuel line 20 from any suction within the cylinder 34. Since the upper end of the rod 36 is open to the atmosphere, it is the piston ring 54 which causes suction within the cylinder 34 so that any chance for gas formation therein is substantially eliminated.

In order to insure that gas formation does not occur within the line 20 between the pump 14 and the injectorigniter units 18, a pressure line maintainer 16 may be provided to keep the pressure of the fuel in the line between the pump and injector-igniter from dropping below a selected value. The maintainer unit 16 is optional, however, and the system will normally operate satisfactorily without it. In this way, the fuel boiling point may be kept sufliciently high by merely elevating or maintaining its pressure. To this end, the unit 16 is comprised of a cast fitting having a through-passageaway 132 and a branch chamber 134 at right angles thereto. The walls of the chamber 134 are externally threaded for receipt of a sleeve 136 which is threaded at both ends and which has an inner annular shoulder 138. When the sleeve 136 is secured to the fitting 130, the shoulder 138 bears tightly against a washer 140 which, in turn, clamps a flexible diaphragm 142 in sealing engagement over the end of the chamber 134. An end cap 144 is threadably engaged in the lower end of the sleeve 136 and houses a spring 146 which biases a piston 148 against the diaphragm 142. In order to limit the travel of the piston 148, the piston is provided with a peripheral flange 150' which is limited in its upward movement by the washer 140 and in its downward movement by the end cap 144.

During normal operation, the pressure in the fuel line 20 greatly exceeds the bias of the spring 146 and maintains the piston 148 downwardly. However, if the pressure in the line becomes too low, the spring biases the piston upwardly to maintain the pressure at a preselected level.

With the fuel thus pumped and distributed to the injector-igniter units 18 under conditions which greatly inhibit the formation of gas therein, it remains for the units 18, mounted directly on the extremely hot internal combustion engine cylinders to efiiciently receive, inject, and ignite precisely controlled amounts thereof in proper timed relation to the engine piston travel.

The injector-igniter units 18 are designed to fit into a standard spark plug opening 100 of an engine with each injector-igniter unit including a metallic casing 164 having an interior downwardly and inwardly tapering bore 168 within which a conforming tapered metal plug 170' is received. The plug supports both a spark plug assembly 171 and an injector asembly 182 and is itself retained in the casing 164 by a split washer and hex-shaped locking ring 177, the latter of which is threadably secured to the said casing.

A bore 172 passes through the length of the plug 170 and receives the spark plug assembly 171 which includes an electrode 174 having an insulated ceramic casing 176. The lower end of the electrode 174 projects down into the engine cylinder in close proximity to a terminal electrode 178 which is rigidly supported from the bottom of the plug 170. The upper end of the electrode 174 is formed so as to receive conventional connecting wires from the engine distributor. The elements forming the spark plug assembly 171 are removable and easily replaced without replacing the entire injector-igniter unit 18.

Disposed in the metallic plug .170 is an elongated upwardly and outwardly tapering nozzle opening or valve seat 175 which extends from the bottom end of the plug 170 through an internally threaded well 174 within which is threadably secured the injector assembly 182. The assembly 182 is comprised of three major components, a valve unit 184, a metal pin 186, and a pin housing 188. The valve unit 184 has a central tapered bore or nozzle continuation 190 which is an extension of the valve seat 175 when the lower end of the valve unit 184 is threadably secured within the well 180'. The upper end of the valve unit 184 has an enlarged head 192 which is externally threaded and has a circumferential fuel groove 194 located between a pair of parallel annular sealing rings 196.

A passageway 198 extends radially inwardly from the circumferential groove 194 to a point short of the bore 190 and then extends upwardly and opens into an annular recess 206 in the top surface of the head 192 surrounding the bore 190. Communication with the recess is controlled by one-way check valve 200 which includes a ball 202 and a retaining spring 204 secured to the top surface of the head 192 for biasing the ball into the closed position. The check valve 200 prevents fuel from returning to the passageway 198 once it has entered the recess chamber 206.

The pin 186 has an elongated tapered stem 208 which mates with the walls of the bore 190 and an enlarged intermediate neck portion 210 and a further enlarged head portion 212. The underside of the neck port 210 has 6 a flexible diaphragm 214 bonded thereto which extends radialy outwardly from the pin and which is secured against the upper surface of the valve unit 184 by a pair of concentric washers 216 which surround the neck portion 210 and provide a normal seat for the head portion 212.

The washers 216 are secured in place by means of the pin housing 188 which is internally threaded at its lower portion and provided with a shoulder 218 so that when it is threadably secured about the valve unit 184, the shoulder 218 will bear against the upper surface of the topmost washer 216 to secure the free outer end of the diaphragm 214 between the top surface of the head 192 and the bottom surface of the lower Washer 216. The interior of the pin housing is hollowed out to form a cylindrical bore 220 which is of greater diameter than the head 212 of the pin 186. The upper end of the bore 220 is internally threaded to receive a guide plug 222 which has an elongated central stem 223 for limiting upward movement of the pin 186. A spring 224 is disposed around the stern 223 and bears against the pin head portion 212 to bias it downwardly against the washers 216.

As depicted in the drawings, the pin housing 188 has an axial passageway 226 which is adapted to receive the fuel line 20 at its upper end and register with the groove 194 and passageway 198 in the valve unit 184 at its lower end. In order to efiiciently distribute the fuel from the fuel line 20 to the groove 194, a small bafile 228 is provided at the point of registry in order to split the fuel flow in opposite directions around the groove to thus maintain a high rate of flow in both directions and avoid fuel stagnation and boil especially when the passageways 226 and 198 are not perfectly aligned.

With the pin 186 biased into a normally closed position in the bore 190, the fuel from the fuel line 20 will be retained in the groove 194, the passageway 198 and the annular recess 206 with the check valve 200- in its biased closed position. With a pressure surge in the line 20 from the power stroke of the piston ring 54- in the fuel injection pump 14, the check valve 200 will overcome the bias of spring 204 and will open to allow the fuel into the recess 206. When the pressure reaches a particular amount, the exertion against the diaphragm 214 will cause the pin 186 to raise upwardly against the bias of the spring 224 and thus allow fuel to stream downwardly through the bore 190 and bore and into the engine cylinder 162. As soon as the power stroke of the pump is complete, the pressure in the fuel line 20 will return to normal and thus cause the check valve 200 as well as the pin 186 to return to the closed position. At this time the timed electrical current supplied by the conventional automobile source means will are between the electrodes 174 and 178 to ignite the fuel-air mixture within the engine cylinder 162.

The high combustion temperatures within the engine cylinder 162 have little effect upon the fuel since it is far removed therefrom within the recess 206 and passageways 198 and 226. It should also be understood that the high pressures in the cylinder 162 will also have very little effect upon the pin 186 since its lowermost end presents the smallest area of exposure to the engine cylinder and the spring 224 need not be extremely large in order to prevent lifting.

Because of the distant location of the fuel prior to injection into the engine cylinder, the elements of the injector-igniter unit 18 need not be heat insulated. The utilization of a metal casing 164, plug 170, and pin 186 will conduct heat away from the stored fuel into the air and surrounding metal parts and yet will keep the tapered bores 190, 175 hot enough to efiiciently vaporize the fuel during injection.

In a general manner, while there has been disclosed effective and efiicient embodiments of the invention, it should be well understood that the invention is not limited 7 r to such embodiments, as there might be changes made in the arrangement, disposition, and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What is claimed is:

1. A fuel injection system for injecting fuel into the cylinders of an internal combustion engine comprising first means for injecting and igniting fuel in said cylinders and pump means for pumping fuel to said cylinders, said first means comprising metallic base means secured adjacent the combustion chamber of said engine for supporting the elements of said combination means, said base means having first and second bores therethrough opening into said combustion chamber, said first bore having an enlarged annular fuel-receiving recess at its upper end, a valve pin slidingly received in said first bore and having an enlarged neck portion and a downwardly and inwardly tapering stem portion, said pin having a closed position with said stem portion in intimate surface contact with the walls of said first bore, biasing means for biasing said pin into said closed position, a flexible means sealingly engaged over said recess and against said pin at the juncture of said neck portion and said stem portion whereby an increase of fuel pressure in said recess will overcome said biasing means and raise said pin from said closed position and spark plug means mounted in said second bore for igniting the fuel injected through said first bore.

2. The invention as described in claim 1 including a second means maintaining a predetermined pressure in said fuel line.

3. The invention as described in claim 2 wherein said second means comprises a member having a chamber therein, said chamber having one end communicating with the fuel in said fuel line, a flexible diagraphm forming an end wall at the other end of said chamber, and biasing means for flexing said diaphragm inwardly when the pressure in said chamber falls below a preselected minimum value.

4. The invention as described in claim 1 wherein said pump means comprises a casing having a plurality of plunger bores uniformly spaced in a circle about an axis of said casing, a fuel chamber centrally disposed in said casing with respect to said plunger bores, said plunger bores being open at both ends, annular seals disposed in the walls of each of said plunger bores adjacent each end thereof, valved inlet means communicating said fuel chamber to the upper end of said plunger bore, valved outlet means communicating the upper end of said plunger bore with said fuel line, a plunger slidably and sealingly received by said seals for reciprocation in each of said plunger bores, said plunger, bore, and seals de- 8 p fining a pumping chamber of hollow circular cross section, annular means on said plunger between said seals for pumping fuel out of said pumping chamber, passageway means below said inlet means extending at an angle from said chamber to said bore for metering fuel to said plunger bore, relief means below said passageway means for allowing fuel in the pumping chamber beneath said annular means to return to said fuel chamber, and means for varying the effective stroke of said annular means.

5. The invention as described in claim 4 wherein said annular means comprises a circumferential ring.

6. The invention as described in claim 4 wherein said passageway means has a circular cross section.

7. A pump for delivering accurately measured amounts of fluid comprising an elongated cylindrical housing open at both ends, inlet means for supplying fluid into said housing, outlet means for permitting fluid egress from said housing, a plunger reciprocally received in said housing, first and second annular seals disposed in said housing adjacent each end thereof, said seals slidingly and sealingly engaging said plunger, and annular means on said plunger for forcing fluid through said outlet means when said plunger is reciprocated, said inlet means including a fluid supply chamber, valve means for supplying fluid from said supply chamber into said housing at a point adjacent said first seal and unrestricted passageway means communicating said housing with said chamher opening into said housing between said valve means and said second seal for accurately metering fluid supply to said housing.

8. The invention as described in claim 7 wherein said passageway means comprises a cylindrical passageway whose longitudinal axis is disposed at an angle with the axis of said housing such that the opening of the passageway into said housing is substantially elliptical in shape.

References Cited UNITED STATES PATENTS 2,083,021 6/1937 High 123-139 XR 2,146,184 2/1939 High 123l39 2,165,696 7/1939 Charter 123-l39 2,250,877 7/1941 Pischinger l23-139.l5 2,432,507 12/1947 Civitaresc 103173 2,645,182 7/1953 Tucker 103173 XR 3,064,581 11/1962 Triclgell 103168 XR 3,129,702 4/1964 Arbanas l23139 3,386,423 6/1968 Vallin 123l39.14

LAURENCE M. GOODRIDGE, Primary Examiner US. Cl. X.R.

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