CA1204358A - Combined fluid pressure actuated fuel and oil pump - Google Patents
Combined fluid pressure actuated fuel and oil pumpInfo
- Publication number
- CA1204358A CA1204358A CA000474596A CA474596A CA1204358A CA 1204358 A CA1204358 A CA 1204358A CA 000474596 A CA000474596 A CA 000474596A CA 474596 A CA474596 A CA 474596A CA 1204358 A CA1204358 A CA 1204358A
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- oil
- piston
- chamber
- pumping
- fuel
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Abstract
ABSTRACT OF DISCLOSURE
Disclosed herein is an oil pump including a movable element reciprocal through a given distance for pumping oil in response to reciprocation of the element, a variable volume oil pumping chamber including an oil inlet and an oil discharge, and mechanism for varying the output of the oil pump notwithstanding the reciprocation of the element through said given distance, which mechanism for varying the oil pump output includes an oil piston defining, in part, the oil pumping chamber, and linkage connecting the element and the piston for displacing the piston in response to movement of the element and for permitting lost motion between the element and the piston.
Disclosed herein is an oil pump including a movable element reciprocal through a given distance for pumping oil in response to reciprocation of the element, a variable volume oil pumping chamber including an oil inlet and an oil discharge, and mechanism for varying the output of the oil pump notwithstanding the reciprocation of the element through said given distance, which mechanism for varying the oil pump output includes an oil piston defining, in part, the oil pumping chamber, and linkage connecting the element and the piston for displacing the piston in response to movement of the element and for permitting lost motion between the element and the piston.
Description
1;iO43$8 TITLE: COMBINED FLUID PRESSURE
ACTUATED FUEL AND OIL PUMP
INVENTOR: FRANK J. WALSWORTH
RELATED APPLICATIONS
This application is a division of my earlier application Serial No. 413,422, filed October 14, 19~2 and entitled "Combined Fluid Pressure Actuated Fuel and Oil Pump".
BACK&ROUND OF THE INVEMTION
The invention generally relates to oil pumping arrangements.
The invention also relates generally to fuel pumping arrangements.
The invention also relates generally to fluid pressure actuated motors.
The invention also relates to internal combustion engines and, more particularly, to two-stroke internal combustion engines and to means for supplying such engines with a fuel/oil mixture.
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~2043S8 Attention is directed to the U.S. Perlewitz Patent 2,935,057 issued May 30, 1960, to the U.S.
Sparrow Patent 3,4~1,318 issued December 2, 1969, to the U.S. ~eitermann Patent 3,653,684 issued April 4, 1972, to the U.S. Shaver Patent 3,913,551 issued October 21, 1975 to the U.S. Schreier Patent 4,142,486 issued March 6, 1979, and to the U.S. Beaton Patent 1,519,478 issued December 16, 1924.
SUMMARY OF THE INVENTION
The invention provides an oil pump including oil pumping means comprising a movable element reciprocal through a given distance for pumping oil in response to element reciprocation, a variable volume oil pumping chamber including oil inlet means and oil discharge means, and me~ns for varying the output of the pumping means notwithctanding the reciprocation of the element ~hrough the given distance, which output varying means includes an oil piston defining, in par~, the oil pumping chamber, an adjustable stop, defining, in part, the oil pumping chamber, and means connecting the element and the piston for displacing the piston in response to movement of the element and for permitting lost motion between the element and the piston.
Other features and advantages of the embodiments of the invention will become known by reference to the following general description, cLaims and appended drawinqs.
IN TRE DRAWINGS
Fig. 1 is a schematic view of one embodiment of a combined fuel and oil pump including a fluid pressure actuated motor.
Fig. 2 is a schematic view o~ ano~her embodim~nt of a combined fuel and aiL pum~ including a fluid pressure actuated motor.
i2043s~
Fig. 3 is a schematic view o~ still another embodiment of a combined fuel and oil pump including a fluid pressure actuated motor.
8efore explaining one embodiment o~ the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology e~ployed herein is ~or the purpose of description and should not be regarded as limiting.
GENERAL DESCRIPTION
Shown in the drawings is a marine propulsion device in the form of an outboard motor 3 which includes a propulsion unit 5 including a power head 7 incorporating a two-stroke internal combustion engine 8, together with a lower unit 9 which is secured to the power head 7 and which rotatably supports a propeller 10 driven by the internal combustion engine 8.
Connected to the internal combustion engine 8 is a combined fuel and oil pump 11 including a fluid pressure motor 13 actuated by a source of alternating relatively high and Low pressu~es.
More particularly, the combined fuel and oil pump 11 comprises a housing 15 and, in addition to the fluid pressure motor 13, include5 an oil pumping means 17 and a fuel pumping means 19.
lZ0~3S8 Still more particularly, the housing 15 includes a peripheral wall 21, together with a top wall 23, an intermediate wall or partition 25, a bottom wall 27, and a lower extension 29. The intermediate wall 25 includes a central bore or port 31 and divides the houslng 15 into an upper compartment 33 and a lower compartment 35.
The fuel pumping means 19 include~ a movable wall or member 39 which is located in the lower compartment 35 and which divides the lower compartment 35 lnto a variable volume fuel pumping chamber 45 located between the intermediate wall 25 and the fuel pumping piston or movable wall or member 39 and a lower or vent chamber 47 which communicates with the atmosphere through a port 49 in the bottom wall 27.
The movable wall or member 39 includes a piston 41 which, at its periphery, has attached thereto a flexible membrane or diaphragm 43 which, in turn, is attached to the peripheral wall 21 of the housing 15.
The fuel pumping means 19 also includes, in the peripheral wall 21, a valved fuel inlet 51 which is adapted to communicate through a conduit 53 wi~h a suitable source 55 o~ fuel and which includes one-way check valve means 57 affording inflow of ~uel in response to an increase in the volume of the fuel pumpinq chamber 45 and which prevents outflow of fuel from the fuel pumping chamber 45.
The fueL pumping means 19 also includes, ~n the peripheral wall 21, a valved fuel outlet ~1 which is adapted to communicate through a conduit 6~ with a device, such as a carburetor 65, for feeding a fuel/oil mixture to the crankcase 67 of the two-stroke engine 8.
~;~043SB
the valved outlet ~l includes one-way check valve means 71 which affords outflow of fuel in response to a decrease in the volume of the fuel pumping chambe~ 45 and which prevents inflow of fuel.
Preferably, the conduit 63 includes an accumulator 75 in the form of a cylinder 77 which, at one end, communicates with the conduit 63 and which, at the other Qr outer end, is vented to the atmosphere by a port 79. Located in the cylinder 77 is a piston 81 which is suitably biased by a spring 83 in the direction toward the conduit 63 so as to provide a variable volume accumulating chamber 85 which serves to reduce or eliminate pulsing of fuel at the discharge end of the conduit 63.
The oil pumping means 17 is located in the lower extension 29 and comprises a cylindrical space 87 which extends from the vent chamber 47 in generally aligned relation to the central port 31 in the intermediate wall 25. Located in the cylindrical space 87 is an oil pumping plunger or element 91 which preferably extends integrally from the fuel pumping piston 41, which is recipcocal in the cylindrical space 87, and which, in part, defines a variable volume oil pumping chamber 93. Seal means 95 is provided between the oil pumping plunger or element 91 and the wall of the cylindrical space 87.
The oil pumping means 17 also in~ludes a valved inlet 101 which i5 adapted to communicate through a conduit 103 with a source 105 of oil and which includes one-way check valve mean3 107 which affords inflow of oil in response to an increase in the volume of the oil pumping chamber 93 and which prevents outflow of oil.
1Z~)4~
The oil pumping means 17 also includes a valve outlet 111. While various other arrangements can be employed, in the illustrated construction, the outlet 111 is designed to delivec oil to the fuel pùmping chamber 45. More particularly, the oil outlet 111 comp~ises a bore 113 which exten~s axially in the oil pumping plunger or element 91, which, at one end, communicates with the oil pumping chamber 93, which, at the other end, includes one or more radial branch ports 115 which communicates with the uel pumping chamber 45, and which includes, intermediate the inlet 101 and the outlet 111, an enlarged central portion 117 having a one way check valve means 119 which affords outflow of oil to the fuel pumping chamber 45 in response to a decrease in the volume of the oil pumping chamber 93 and which prevents inflow into the oil pumping chamber 93.
The fluid pressure actuated motor 13 is located generally in the upper compartment 33 and is connected to the oil pumping plunger 91 and to the fuel pumping piston 41 so as to effect common reciprocation thereof through a given stroke or distance. More particularly, the fluid pressure actuated motor 13 is responsive to a source of alternating relatively high and low pressures for effectinq reciprocation of the fuel pumping piston 41 and the oil pumping plunger or element 91 at a frequency less than the frequency of the alternation of the relatively high and low pressures. Still more particularly, the fluid pressure actuated motor 13 includes a movable wall 121 which divides the upper compartment 33 into an upper, i i204~S8 relatively low pressure variable volume chamber 123 and a lower, relatively high pressure variable volume chamber 125. The movable wall 121 includes a central or motor pi~ton 127 which, at its outer periphery, is connected to a flexible membrane or diaphragm 129 whic~h, at its outer periphery, is secured to the peripheral housing wall 21 so as to divide the upper compartment 33 into the before-mentioned relatively low and high pressure chambers.
The central motor piston 127 i also preferably integrally connected with the fuel pumping piston 41 and with the oil pumping plunger or element 91 for common movement. In thi last regard, the combined motor piston 127, fuel pumpin~ piston 41, and oil pumping plunger 91 includes a central portion 131 which extends from the fuel pumping piston 41 toward the motor piston 127 and through the central bore or port 31 in the intermediate wall 25, and a connecting portion which forms an open valve cage 135 and which connect~ the central portion 131 to the motor piston 127. A suitable seal 139 i5 provided between the intermediate wall 25 and the central portion 131.
The fluid pressure actuated motor 13 further includes mean3 biasing the movable wall 121 so as to displace the movable wall 121 in the direction minimizing the volume of the high pressure chamber 125 and maximizing the volume of the low p~essure chamber 123. In the illustrated construction, such ~eans comprises a helical spring 141 which, at one end, ~ears against the upper or top hou ing wall 23 and which, at the other end, bear~ against the ~o~or piston 127.
The fluid pressure actuated motor 13 also includes means 151 or creating a pressure differential 1;2()4358 between the low and high pressure chambers 123 and 125, respectively, so as to displace the movable wall 121 in the direction minimizing the volume of the low pressure chamber 123 and maximizing the volume of the high pressure chamber 125. While various arrangements can be employed, in the illustrated construction, such means includes means adapted for connection to a ~ource of alternating relatively high and low pressures and including means permitting flow from the low pressure chamber 123 and preventing flow to the low pressure chamber 123, and means permitting flow to the high pressure chamber 125 and preventing flow from the high pressure chamber 125.
Preferably, the source of alternating relatively high and low pressures is the crankcase 67 of the two-stroke engine 8. However, other sources of relatively high and low pressures can be employed. In addition, relatively high and low pressure can refer to two positive pressures above atmospheric pressure, to two negative pressures below atmospheric pressure, or to one positive pressure above atmospheric pressure and one negative pressure below atmospheric pressure.
Still more speciically, the means 151 for creating the pressure differential between the relatively low and high pressure cylinders 123 and 125, respectively, also includes a conduit system 161 including a main conduit 163 adapted to be connected to the source of alternating high and low pressures, such as the crankcase 67 of the two-stroke engine 8, together with a first or low pressure branch conduit 165 which communicates between the low pressure chamber 1;i~04358 g 123 and the main conduit 163 and a second oc high pressure branch conduit 167 which communicates between the high pressure chamber 125 and main conduit 163.
Included in the low pressure branch conduit 165 is a one-way check valve 169 which permi~s flow fro~the low pressure chamber 123 and prevents flow to the low pressure chamber 123. Located in the high pressure branch conduit 167 is a one way check valve 171 which permits ~low to the high pressure chamber 125 and which prevents flow from the high pressure chamber 125.
Accordingly, alternating pressure pulses of relatively high and low pressures present in the main conduit 163 will cause the existence o~ a relatively high pressure in the high pressure chamber 125 and a relatively low pressure in the low pressure chamber 123, which pressure differential is of sufficient magnitude, as compared to the biasing action of the movable wall biasing spring 141, so that the pressure differential is effective to cause move~ent of the movable wall 121 from a position in which the high pressure chamber 125 is at a minimum volume to a position in which the low pressure chamber 123 is at a minimum volume.
Preferably, the conduit system 161 also includes means ~or relieving an excessive pressure differential. In this regard, the conduit system 161 includes a bypass conduit 175 which communicates with the low and high pressure branch conduits 165 and L67, respectively, so as to be in direct communication wfth the low and high pressure chambers 123 and 125, respectively. The bypass conduit 175 includes a one-way ~204a~
pressure regulating valve 177 including a ball member 179 which is engaged with a seat 181 and held in such engagement by sprinq 183 designed to release the ball member 179 ~rom engagement with the seat 181 in the event of an excessive differential pressure.
The fluid pressure actuated motor 13 also incl~des means responsive to piston movement minimizing the volume of the low pre~sure chamber 123 ~or establishing communication between the low and high pressure chambers 123 and 125, respectivelY, so as thereby to reduce or minimize the pressure differential between the low an high pressure chambers 123 and 125, respe~tively, and thereby permit displacement o~ the movable wall 121 by the biasing spring 141 in the direction minimizing the volume of the high pressure chamber 125 and maximizing the volume o~ the low pressure chamber 123. While such means can be provided, at least in part, by a conduit (not shown) bypassing ~he motor piston 127, in the illustrated construction, such means comprises a central port 191 in the motor piston 127, together with a valve member 193 which is located in the open cage 135 of the combined motor piston 127, fuel pumping piston 41 and oil pumping plunger 91, and which is movable between a closed and an open position. Preferably, the valve member 193 includes a downwardly extending stem 195 which is received in a mating recess or axial bore 197 in the central portion 131 of the combined ~iston so as to guide movement of the valve member 193 between its open and close~ positions.
In addition, the means fo~ effecting communication between the low and high pressure chambe!s 123 and 125, respectively, includes a helical valve member biasing spring 201 which urge the valve member 193 to the open position and which, at one end, bears against the upper or top wall 23 Oe the housing 15 and which, at the other end, extends through the port 191 in the motoc piston 127 and bears against the upper sur~ace of the valve member 193. The valve member biasing spring 201 is designed so as to be operable to overcome the pressure differential between the low and high pressure chambers 123 and 125, respectively, and thereby to displace the valve member 193 toward the open position as the motor piston 127 approaches the position minimizing the volume o~ the low pressure chamber 123.
Means are also provided for insuring full opening movement of the valve member 193 in response to approach of the motor piston 127 to the position minimizing the volume o~ the low pressure chamber 123.
Such means is provided in the low pressure chamber 123 and comprises means defining an intermediate chamber 211 communicating with the motor piston port 191 and providing resistance to flow from the intermediate chamber 211 to the low pressure chamber 123 upon initial opening of the valve member 193 so as thereby to effect reduction in the pressure dif~erential between the high pressuce chamber 125 and the intermediate chamber 211 and thereby to cause move~en~
of the valve member 193 to the full opened position.
Such movement substantially reduces the pressure di~ferential between ~he low pressure chamber 123 and the high pressure chamber 125, and thereby permits movement o~ the movable wall 121 to minimize the volume ~;20435~
of the high pressure chamber 125 in cesponse to the action of the motor piston biasing spring 14L. While various arrangements can be employed, in the illustrated construction, such means comprises an annular flange or ring 213 extending inwardly of the low pressure chamber 123 from the top wall 23 of the houslng 15 and in radially outward relation from the valve member biasing spring 201 and in radially inward relation from the motor piston biasing spring 141. In addition, such means comprises a cooperating annular flanqe or ring 215 extending from the motor piston 127 toward the hou~ing top wall 23 and movable into telescopic relation to the flange or ring 213 as the motor piston 127 approaches the end of the stroke minimizing the volume of the low pressure chamber 123 so as to telescopically form the intermediate chamber 211 and to provide resistance to flow from the intermediate chamber 211 to the low pressure chamber 123.
Such resistance to flow between the intermediate chamber 211 and the low pressure chamber 123 cause3 deminishment in the resistance to flow or pressure drop between the high pressure chamber 125 and the intermediate chamber 211, thereby assuring action of the valve member biasing spring 201 to effect displacement of the valve member lg3 to its fully open position.
The fluid pressure actuated ~otor L3 ~lso includes means responsive to piston movement minimizing the volume of the high pressure chamber 125 for discontinuing communication between the low and high prescure chambers 123 and 125, respectively, so as to ~043~
thereby permit the creation o~ fluid pressure differential between the low and high pressure chambers 123 and 125 by the fluid pressure differential creating means and thereby also to ef~ect dlsplacement of the motor piston 127 in the direction minimizing the volume of the low pressure chamber 123 and maximizing the volu~e of the high pressure chamber 125. While other arrangements can be employed, in the illustrated construction, such means comprises a pluraLity of studs or posts 221 which extend upwardly from the intermediate partition or wall 25 toward the valve member 193 and through the open valve cage 135 for engagement with the valve member 193 to ~eat the valve member 193 in the closed position as the motor piston 127 approaches the position minimizing the volume of the high pressure chamber 125.
Thus, in operation, the peesence of alternating high and low pressures in the conduit system 161 causes (assuming the valve member 193 to be in the closed position) buildup and maintenance of higher pressure in the relatively high pressure chamber 125 and reduction and maintenance of low pressure in the low pressure chamber 123. The pressure differential thus created causes displacement of the movable wall 121, including the motor piston 127, against the action of the motor piston biasing spsing 141, to the position minimizing the voLume of the low pressure chamber 123. As the motor piston 127 approaches the position minimizing the volume of the low pressure chamber 123, the valve member biasin~
spring 201 serves to open the motor piston port 191 by displacing the valve member 193 to the open position 1;~04358 and thereby to reduce or minimize the pressure differential and permit displacement of the movable wall 121 by action of the biasing spring 141 to the posi~ion minimizing the volume o~ the high pressure chamber 125. During such movement, and in the absence of a pressure differential, the valve member 193 remains in the open position under the action o~ the valve member biasing spring 201.
Upon approach o~ the movable wall 121, including the motor piston 127, to the position minimizing the volume o~ the high pressure chamber 125, the studs 221 engage the valve member 193 to cause movement thereof to the closed position. With the motor piston port 191 thus closed, the pressure differential is again created and the movable wall 121 is again displaced in the opposite direction to commence another cylce of operation. As the fuel pumping 41 and the oil pumping plunger 91 have common movement with the motor piston 127, the fluid actuated motor 13 causes reciprocation of these components at a frequency less than the frequency exciting the motor 13, i.e.~ less than the rate of alternation of the high and low pressures in the source.
Preferably, means are provided ~or selectively adjusting the discharge rate o~ the oil pumping means 17, notwithstanding displacement of the oil pumping plunger 91 through a generally constant stroke. While various other arrangements can be employed, in the illustrated construction, such means comprises a subchamber 231 which extends ~ro~ the oil pumping chamber 93 and which includes therein a ~loating piston 233. A suitable seal 235 is provided between the ~20435~
floaeing piston 233 and the wall o~ the subchamber 231.
The floating piston 233 includes, at the outer end thereof, a portion 237 which extends outwardly of the subchamber 231 and which is engaged by a cam 239 which is connected by a suitable linkage 241 shown in dotted outline to the engine throttle 243 and which is, accordingly, selectively positionable in accordance with selective positioning of the engine throttle 243.
The cam 239 thus variably restricts outward movement of the floating piston 233 so as to thereby control the effective pumping stroke of the oil pumping plunger 91.
A more detailed description of the arrangement for varying the discharge rate of the oil pumping means 17 can be found in my co-pending Application Serial No.
324,145 which is incorporated herein by re~erence.
The combined fuel and oil pumping device 11 can be mounted to the block of the two-stroke engine 8 so as to afford immediate connection to the engine crankcase 67 and can be connected to remote sources o~
oil and fuel. Alternately, if desired, the combined fuel pump and oil pump 11 can be located at a remote location more or less adjacent to or with the sources of fuel and oil and a conduit (not shown) can extend between the crankcase 67, or other source of alternating high and low pressures, and the combined fuel and oil pumping device 11.
Shown in Fig. 2 is another embodiment of a combined fuel and oil pump 301 in accordance with the invention. The construction shown in Fig. 2 is generally identical to that shown in Fig. 1, and the same reference numeral have applied for like components, except for the arrangement for insuring ~043~
full opening of the valve member 193 and the arrangement for varying the amount o~ oil ~low and the oil discharge arrangement.
With respect to the arrangement or means ~or insuring full opening movement of the valve member 193 in response to approach o~ the motor piston 127 to the posi~ion minimizing the volume o~ the low pcessure chamber 123, in the construction illustrated in Fig. 2, the rings 213 and 215 have been omitted, thereby also omitting provision of the intermediate chamber 211.
Instead, there is provided a member or post 302 which ~ixedly depends downwardly from the top housing wall 23 in position for engaging the valve member 193 as the movable wall 121 minimizes the volume o~ the low pressure chamber 123. Such engagement causes "cracking" or slight openinq of the port 191, thereby somewhat diminishing the pressure dif~erential across the movable wall 121. Such diminishment of the pressure differential facilitates immediately subsequent operation o~ the poppet valve member biasing spring 201 to displace the valve member 193 so as to fully open the port 191 and thereby to substantially eliminate the pressure differential and obtain wall movement in the direction minimizing the volume of the high pressure chamber 125 under the action of the movable wall biasing sprinq 141. I~ is also noted that the post 302 serves to stabilize or locate the upper end of the poppet valve member biasing spring 201.
In the embodiment shown in Fi~. 2, the oil pumping arrangement includes an oil pumping piston 303 which deines, in part, a variable volume oil pumping chamber 393. The oil pumping piston 303 i5 slidably i21)43SB
engaged by the movable element 91 by means of an upper end 305 of the piston 303 being located in an enclosed central chamber 307 in the movable element 91. A mid portion 309 of the piston 303 extends outwa~dly Oe the chamber 307 through an openinq 311 and connects the upper end 305 of the piston 303 to a lower portion 313 in tbe cylindrical space 87. The upper end 305 of the piston 303 is larger ~han the opening 311 so when the movable element 91 moves upwardly, the piston 303 moves with the movable element 91. Seal means 315 are provided above a lower end 317 of the piston 303 and between the lower portion 313 of the piston and the wall of the cylindrical space 87. The location of the seal means 315 permits the lower end 317 of the piston to extend below the valve inlet 101 and outlet 319.
In the embodiment, the oil pumping means 17 includes a valved outlet 319 which extends coaxially with the valved inlet 101 but on ~he opposite side of the cylindrical space 87. The outlet 319 includes a one way check valve 321 and affords outflow of oil to the conduit 63 for feeding the oil to the carburetor 65.
In the embodiment shown in Fig. 2, the means for selectively adjusting the discharge rate of the oil pumping mean~ includes an adjustable stop 323 which defines, in part, the oil pumping chamber 393. The adjustable stop 323 is located in the cylindrical space 87 below the inlet 101 and outlet 319. A suitable seal 325 is provided beSween the adjustable stop 323 and the wall of the cylindrical space B7, and ~ portion 327 of the adjustable stop above the seal 325 has a diameter les than the diameter of the cylindrical space 87 to permit the upper portion 327 of the adjustable stop to extend above the inlet 101 and outlet 319. The lower end o~ the adjustable stop 323 includes a portion 329 which extends outwardly of the cylindrical space 87 and which is engaged by the cam 239. The cam 239 operates a~ previously described.
The oil pumping means also includes biasing mean~ for biasing the oil piston 303 toward the adjustable stop 323. The biasing means comprises a spring 331 between the upper end 305 of the piston and the movable element 91 in the central chamber 307.
In operation, as the movable element 91 moves downward, the oil piston 303 move~ downwardly an equal distance. The biasing means or spring 331 i5 preloaded so that it will not deflect due to either oil pump pressure or seal friction. As the piston 303 moves downwardly, the oil pumping chamber 393 will be reduced in volume and will force oil out through the valved outlet 319. However, when the oil piston 303 contacts the adjustable stop 323, it will move no further and the remaining stroke of the movable element 91 will be taken up or lost by deflecting the biasing means or spring 331. The location of the adjustable stop 323 will, ~herefore, vary the volume o the oil pumping chamber 393 and the amount of oil pumped by the pumping means.
Shown in Fig. 3 is still another embo~i~ent of a combined ~uel and oil pump 401 which is associated with the internal combustion engine 8 and which embodies various of the ~eatureR of the invention. The construction shown in Figure 3 is generally identical to the construction shown in Figure 2 and the same reference numerals have been applied for like ~2043S~
components, except that the ~uel pumping arrangement has been slightly ~odified, except that the oil pumping arrangement has been modified to provide for variation in the output of the oil pump in accordance with engine speed without use of a ~ovable part 239 or element 323 and associated linkage, and except that th~ one-way pressure-regulating valve 177 has been omitted and the stroke of the motor piston 127 varies in accordance with engine speed. In this last regard, the poppe~
valve biasing spring 201 has a spring rate which serves to open ~he port lgl prior to the full stroke of the motor piston 127 when the engine 8 is operating at low speed and which serves to open the port 191 upon completion of the full stroke of the motor piston 127 when the engine 8 is operating at high speed.
More particularly, as is well known, in a two-stroke engine, such as the engine 8, movement of the piston relative to the cylinder and crankcase 67 serves to produce in the crankcase, cyclical conditions of relatiYely high and low pressures defining a crankcaee pressure amplitude which varies in accordance with engine speed, i.e., which increases ~ith engine speed. A~, for example, when engine operation is at idle or low speed, the pressures in the crankcase can vary fro~ about +3 psi to about -3 psi, thus providing a crankcase pressure amplitude of 6 p5i. Also, for example, when operating at high engine speed, the pressure in the crankcase can vary fro~ about ~S psi to -6 p3i, or from about +10 psi to about -1 psi, thus providing a crankcase pressure amplitude of 11 pSi.
Under operating conditions, because of the connec~ion of the crankcase 67 to the low and high ~2043~i~
pressure chambers 123 and 125, respectively, and the one-way check valves 169 and 171, the pressure conditions in the low and high pressure chambers 123 and 125, re~pectiveLy, rapidly reflect the pressuces in the crankcase 67 an provide a pressure differential acros~ the movable motor pi~ton 127, i.e., between the low.~nd high pressure chambers 123 and 125, respectively, which pressure differential has an amplitude approxi~ating the crankcase pressur~
amplitude.
The poppet valve bia~ing spring 201, as already indicated, has a spring rate such that partial movement of the motor piston 127 between the positionq causing minimum volume o~ the low and high pressure chambers 123 and 125, respectively, will cause such contraction o~ the poppet valve bia ing spring 201 as to overcome the force on the valve member 193 occurring in response to the pressure differential when the engine 8 i5 operating at low speed. However, the spring ra~e is such that, whenever the engine 8 operates a~ high speed, the force created by the pressure differential is sufficiently great to provide greater travel or full travel of the movable wall 121 or motor piston 127 prior to opening of the port 191~
As a consequence, the mator piston 127 is provided with a stroke which varies with engine speed, i.e., is provided with a stroke which increase in length with engine speed.
The fuel pumping arrangement employed in ~he construction shown in Fig. 3 varies from that sh~wn in Figs. 1 and 2 by placing the valved fuel inlet 51 in communication with the lower chamber 47 (which is, of course, not vented). In addition, the fuel pumping piston 39 is provided wit~ one or more apertures 411, each having associated therewith a one-way check valve member 413 affording flow from the lower chamber 47 to the upper chamber 45 and preventing ~low ~rom the upper chamber 45 to the lower chamber 47. The stroke of fuel pumping member or piston 39 is identical to the stroke of the motoc piston 127 and hence the amount of fuel pumped will vary in accordance wi~h engine speed, i.e., will increase with increa ing engine speed.
If desired, a fuel pump construction identical to that shown in Figs. 1 and 2 could aLso be employed.
The oil pumping arrangement differs from the construction shown in Figs. 1 and 2 in that the amount of oil pumped is automatically varied in accordance with engine speed and in that, due to a lost-motion connection between the motor piston 127 and the oil pumpinq piston 303, oil pumping does not occur until after a first engine speed level, which can be intermediate the low and high engine speeds, and which, above the first enqine speed level, increases wi~h increa~ing engine speed.
In thi3 last regard, the oil pumping piston 303 is connected to the motor piston 127 to provide for common movement therewith during a portion o~ the motor piston stroke and to provide for lost-motion during another portion of the motor piston 127 stroke. In this regard, the upper end of the oil pumping piston 303 i~ provided with an axial recess or bore 415 which is defined, at the upper end thereof, by an internal annular flange 417 deining an opening 419, and the ~204æ~
motor piston 127 is provided with an extension 421 which projec~s through the opening 419 provided by the annualar ~lange 417 and include~, at the lower end, an enlarged head 4~3 which cannot pass through the opening 419 defined by the annualar flange 417. Thus, initial upst~oke movement o~ the motor piston 127 from the positio~ minimizing the volume of the high pressure chamber 125 does not cause accompanying movement of the oil pumping piseon 313. However, before the motor piston 127 raaches the position minimizing the volume of low pressure chamber 123, the head 423 engages the flange 417 to cause common movement of the oil pumping piston 303 with the motor piston 127. Initial downstroke motion of the motor piston 127 does not cause the oil pumping piston movement until the head 423 engages the blind end of the recess or bore 415.
Thus, oil pumping operation occurs only at the top of the up~trok~ of the motor piston movement and at the bottom of the downstroke o~ the motor piston movement.
Accordingly, the oil pumping arrangement disclosed in FigO 3, provides for little or no pumping at low engine speeds and for increasing oil pumping with increasing speeds above low engine qpeed.
As in the construction shown in Fig. 2, the oil d$scharge from the output 319 is conveyed to the fuel discharge conduit 63 for mixture therewith.
However, if desired, the discharged oil could be conveyed for mixture with the ~uel in either the ueeer chamber 45 or in the lower cha~ber 47.
Various of the featureq of the invention are set forth in the following claims.
ACTUATED FUEL AND OIL PUMP
INVENTOR: FRANK J. WALSWORTH
RELATED APPLICATIONS
This application is a division of my earlier application Serial No. 413,422, filed October 14, 19~2 and entitled "Combined Fluid Pressure Actuated Fuel and Oil Pump".
BACK&ROUND OF THE INVEMTION
The invention generally relates to oil pumping arrangements.
The invention also relates generally to fuel pumping arrangements.
The invention also relates generally to fluid pressure actuated motors.
The invention also relates to internal combustion engines and, more particularly, to two-stroke internal combustion engines and to means for supplying such engines with a fuel/oil mixture.
'~P
~2043S8 Attention is directed to the U.S. Perlewitz Patent 2,935,057 issued May 30, 1960, to the U.S.
Sparrow Patent 3,4~1,318 issued December 2, 1969, to the U.S. ~eitermann Patent 3,653,684 issued April 4, 1972, to the U.S. Shaver Patent 3,913,551 issued October 21, 1975 to the U.S. Schreier Patent 4,142,486 issued March 6, 1979, and to the U.S. Beaton Patent 1,519,478 issued December 16, 1924.
SUMMARY OF THE INVENTION
The invention provides an oil pump including oil pumping means comprising a movable element reciprocal through a given distance for pumping oil in response to element reciprocation, a variable volume oil pumping chamber including oil inlet means and oil discharge means, and me~ns for varying the output of the pumping means notwithctanding the reciprocation of the element ~hrough the given distance, which output varying means includes an oil piston defining, in par~, the oil pumping chamber, an adjustable stop, defining, in part, the oil pumping chamber, and means connecting the element and the piston for displacing the piston in response to movement of the element and for permitting lost motion between the element and the piston.
Other features and advantages of the embodiments of the invention will become known by reference to the following general description, cLaims and appended drawinqs.
IN TRE DRAWINGS
Fig. 1 is a schematic view of one embodiment of a combined fuel and oil pump including a fluid pressure actuated motor.
Fig. 2 is a schematic view o~ ano~her embodim~nt of a combined fuel and aiL pum~ including a fluid pressure actuated motor.
i2043s~
Fig. 3 is a schematic view o~ still another embodiment of a combined fuel and oil pump including a fluid pressure actuated motor.
8efore explaining one embodiment o~ the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology e~ployed herein is ~or the purpose of description and should not be regarded as limiting.
GENERAL DESCRIPTION
Shown in the drawings is a marine propulsion device in the form of an outboard motor 3 which includes a propulsion unit 5 including a power head 7 incorporating a two-stroke internal combustion engine 8, together with a lower unit 9 which is secured to the power head 7 and which rotatably supports a propeller 10 driven by the internal combustion engine 8.
Connected to the internal combustion engine 8 is a combined fuel and oil pump 11 including a fluid pressure motor 13 actuated by a source of alternating relatively high and Low pressu~es.
More particularly, the combined fuel and oil pump 11 comprises a housing 15 and, in addition to the fluid pressure motor 13, include5 an oil pumping means 17 and a fuel pumping means 19.
lZ0~3S8 Still more particularly, the housing 15 includes a peripheral wall 21, together with a top wall 23, an intermediate wall or partition 25, a bottom wall 27, and a lower extension 29. The intermediate wall 25 includes a central bore or port 31 and divides the houslng 15 into an upper compartment 33 and a lower compartment 35.
The fuel pumping means 19 include~ a movable wall or member 39 which is located in the lower compartment 35 and which divides the lower compartment 35 lnto a variable volume fuel pumping chamber 45 located between the intermediate wall 25 and the fuel pumping piston or movable wall or member 39 and a lower or vent chamber 47 which communicates with the atmosphere through a port 49 in the bottom wall 27.
The movable wall or member 39 includes a piston 41 which, at its periphery, has attached thereto a flexible membrane or diaphragm 43 which, in turn, is attached to the peripheral wall 21 of the housing 15.
The fuel pumping means 19 also includes, in the peripheral wall 21, a valved fuel inlet 51 which is adapted to communicate through a conduit 53 wi~h a suitable source 55 o~ fuel and which includes one-way check valve means 57 affording inflow of ~uel in response to an increase in the volume of the fuel pumpinq chamber 45 and which prevents outflow of fuel from the fuel pumping chamber 45.
The fueL pumping means 19 also includes, ~n the peripheral wall 21, a valved fuel outlet ~1 which is adapted to communicate through a conduit 6~ with a device, such as a carburetor 65, for feeding a fuel/oil mixture to the crankcase 67 of the two-stroke engine 8.
~;~043SB
the valved outlet ~l includes one-way check valve means 71 which affords outflow of fuel in response to a decrease in the volume of the fuel pumping chambe~ 45 and which prevents inflow of fuel.
Preferably, the conduit 63 includes an accumulator 75 in the form of a cylinder 77 which, at one end, communicates with the conduit 63 and which, at the other Qr outer end, is vented to the atmosphere by a port 79. Located in the cylinder 77 is a piston 81 which is suitably biased by a spring 83 in the direction toward the conduit 63 so as to provide a variable volume accumulating chamber 85 which serves to reduce or eliminate pulsing of fuel at the discharge end of the conduit 63.
The oil pumping means 17 is located in the lower extension 29 and comprises a cylindrical space 87 which extends from the vent chamber 47 in generally aligned relation to the central port 31 in the intermediate wall 25. Located in the cylindrical space 87 is an oil pumping plunger or element 91 which preferably extends integrally from the fuel pumping piston 41, which is recipcocal in the cylindrical space 87, and which, in part, defines a variable volume oil pumping chamber 93. Seal means 95 is provided between the oil pumping plunger or element 91 and the wall of the cylindrical space 87.
The oil pumping means 17 also in~ludes a valved inlet 101 which i5 adapted to communicate through a conduit 103 with a source 105 of oil and which includes one-way check valve mean3 107 which affords inflow of oil in response to an increase in the volume of the oil pumping chamber 93 and which prevents outflow of oil.
1Z~)4~
The oil pumping means 17 also includes a valve outlet 111. While various other arrangements can be employed, in the illustrated construction, the outlet 111 is designed to delivec oil to the fuel pùmping chamber 45. More particularly, the oil outlet 111 comp~ises a bore 113 which exten~s axially in the oil pumping plunger or element 91, which, at one end, communicates with the oil pumping chamber 93, which, at the other end, includes one or more radial branch ports 115 which communicates with the uel pumping chamber 45, and which includes, intermediate the inlet 101 and the outlet 111, an enlarged central portion 117 having a one way check valve means 119 which affords outflow of oil to the fuel pumping chamber 45 in response to a decrease in the volume of the oil pumping chamber 93 and which prevents inflow into the oil pumping chamber 93.
The fluid pressure actuated motor 13 is located generally in the upper compartment 33 and is connected to the oil pumping plunger 91 and to the fuel pumping piston 41 so as to effect common reciprocation thereof through a given stroke or distance. More particularly, the fluid pressure actuated motor 13 is responsive to a source of alternating relatively high and low pressures for effectinq reciprocation of the fuel pumping piston 41 and the oil pumping plunger or element 91 at a frequency less than the frequency of the alternation of the relatively high and low pressures. Still more particularly, the fluid pressure actuated motor 13 includes a movable wall 121 which divides the upper compartment 33 into an upper, i i204~S8 relatively low pressure variable volume chamber 123 and a lower, relatively high pressure variable volume chamber 125. The movable wall 121 includes a central or motor pi~ton 127 which, at its outer periphery, is connected to a flexible membrane or diaphragm 129 whic~h, at its outer periphery, is secured to the peripheral housing wall 21 so as to divide the upper compartment 33 into the before-mentioned relatively low and high pressure chambers.
The central motor piston 127 i also preferably integrally connected with the fuel pumping piston 41 and with the oil pumping plunger or element 91 for common movement. In thi last regard, the combined motor piston 127, fuel pumpin~ piston 41, and oil pumping plunger 91 includes a central portion 131 which extends from the fuel pumping piston 41 toward the motor piston 127 and through the central bore or port 31 in the intermediate wall 25, and a connecting portion which forms an open valve cage 135 and which connect~ the central portion 131 to the motor piston 127. A suitable seal 139 i5 provided between the intermediate wall 25 and the central portion 131.
The fluid pressure actuated motor 13 further includes mean3 biasing the movable wall 121 so as to displace the movable wall 121 in the direction minimizing the volume of the high pressure chamber 125 and maximizing the volume of the low p~essure chamber 123. In the illustrated construction, such ~eans comprises a helical spring 141 which, at one end, ~ears against the upper or top hou ing wall 23 and which, at the other end, bear~ against the ~o~or piston 127.
The fluid pressure actuated motor 13 also includes means 151 or creating a pressure differential 1;2()4358 between the low and high pressure chambers 123 and 125, respectively, so as to displace the movable wall 121 in the direction minimizing the volume of the low pressure chamber 123 and maximizing the volume of the high pressure chamber 125. While various arrangements can be employed, in the illustrated construction, such means includes means adapted for connection to a ~ource of alternating relatively high and low pressures and including means permitting flow from the low pressure chamber 123 and preventing flow to the low pressure chamber 123, and means permitting flow to the high pressure chamber 125 and preventing flow from the high pressure chamber 125.
Preferably, the source of alternating relatively high and low pressures is the crankcase 67 of the two-stroke engine 8. However, other sources of relatively high and low pressures can be employed. In addition, relatively high and low pressure can refer to two positive pressures above atmospheric pressure, to two negative pressures below atmospheric pressure, or to one positive pressure above atmospheric pressure and one negative pressure below atmospheric pressure.
Still more speciically, the means 151 for creating the pressure differential between the relatively low and high pressure cylinders 123 and 125, respectively, also includes a conduit system 161 including a main conduit 163 adapted to be connected to the source of alternating high and low pressures, such as the crankcase 67 of the two-stroke engine 8, together with a first or low pressure branch conduit 165 which communicates between the low pressure chamber 1;i~04358 g 123 and the main conduit 163 and a second oc high pressure branch conduit 167 which communicates between the high pressure chamber 125 and main conduit 163.
Included in the low pressure branch conduit 165 is a one-way check valve 169 which permi~s flow fro~the low pressure chamber 123 and prevents flow to the low pressure chamber 123. Located in the high pressure branch conduit 167 is a one way check valve 171 which permits ~low to the high pressure chamber 125 and which prevents flow from the high pressure chamber 125.
Accordingly, alternating pressure pulses of relatively high and low pressures present in the main conduit 163 will cause the existence o~ a relatively high pressure in the high pressure chamber 125 and a relatively low pressure in the low pressure chamber 123, which pressure differential is of sufficient magnitude, as compared to the biasing action of the movable wall biasing spring 141, so that the pressure differential is effective to cause move~ent of the movable wall 121 from a position in which the high pressure chamber 125 is at a minimum volume to a position in which the low pressure chamber 123 is at a minimum volume.
Preferably, the conduit system 161 also includes means ~or relieving an excessive pressure differential. In this regard, the conduit system 161 includes a bypass conduit 175 which communicates with the low and high pressure branch conduits 165 and L67, respectively, so as to be in direct communication wfth the low and high pressure chambers 123 and 125, respectively. The bypass conduit 175 includes a one-way ~204a~
pressure regulating valve 177 including a ball member 179 which is engaged with a seat 181 and held in such engagement by sprinq 183 designed to release the ball member 179 ~rom engagement with the seat 181 in the event of an excessive differential pressure.
The fluid pressure actuated motor 13 also incl~des means responsive to piston movement minimizing the volume of the low pre~sure chamber 123 ~or establishing communication between the low and high pressure chambers 123 and 125, respectivelY, so as thereby to reduce or minimize the pressure differential between the low an high pressure chambers 123 and 125, respe~tively, and thereby permit displacement o~ the movable wall 121 by the biasing spring 141 in the direction minimizing the volume of the high pressure chamber 125 and maximizing the volume o~ the low pressure chamber 123. While such means can be provided, at least in part, by a conduit (not shown) bypassing ~he motor piston 127, in the illustrated construction, such means comprises a central port 191 in the motor piston 127, together with a valve member 193 which is located in the open cage 135 of the combined motor piston 127, fuel pumping piston 41 and oil pumping plunger 91, and which is movable between a closed and an open position. Preferably, the valve member 193 includes a downwardly extending stem 195 which is received in a mating recess or axial bore 197 in the central portion 131 of the combined ~iston so as to guide movement of the valve member 193 between its open and close~ positions.
In addition, the means fo~ effecting communication between the low and high pressure chambe!s 123 and 125, respectively, includes a helical valve member biasing spring 201 which urge the valve member 193 to the open position and which, at one end, bears against the upper or top wall 23 Oe the housing 15 and which, at the other end, extends through the port 191 in the motoc piston 127 and bears against the upper sur~ace of the valve member 193. The valve member biasing spring 201 is designed so as to be operable to overcome the pressure differential between the low and high pressure chambers 123 and 125, respectively, and thereby to displace the valve member 193 toward the open position as the motor piston 127 approaches the position minimizing the volume o~ the low pressure chamber 123.
Means are also provided for insuring full opening movement of the valve member 193 in response to approach of the motor piston 127 to the position minimizing the volume o~ the low pressure chamber 123.
Such means is provided in the low pressure chamber 123 and comprises means defining an intermediate chamber 211 communicating with the motor piston port 191 and providing resistance to flow from the intermediate chamber 211 to the low pressure chamber 123 upon initial opening of the valve member 193 so as thereby to effect reduction in the pressure dif~erential between the high pressuce chamber 125 and the intermediate chamber 211 and thereby to cause move~en~
of the valve member 193 to the full opened position.
Such movement substantially reduces the pressure di~ferential between ~he low pressure chamber 123 and the high pressure chamber 125, and thereby permits movement o~ the movable wall 121 to minimize the volume ~;20435~
of the high pressure chamber 125 in cesponse to the action of the motor piston biasing spring 14L. While various arrangements can be employed, in the illustrated construction, such means comprises an annular flange or ring 213 extending inwardly of the low pressure chamber 123 from the top wall 23 of the houslng 15 and in radially outward relation from the valve member biasing spring 201 and in radially inward relation from the motor piston biasing spring 141. In addition, such means comprises a cooperating annular flanqe or ring 215 extending from the motor piston 127 toward the hou~ing top wall 23 and movable into telescopic relation to the flange or ring 213 as the motor piston 127 approaches the end of the stroke minimizing the volume of the low pressure chamber 123 so as to telescopically form the intermediate chamber 211 and to provide resistance to flow from the intermediate chamber 211 to the low pressure chamber 123.
Such resistance to flow between the intermediate chamber 211 and the low pressure chamber 123 cause3 deminishment in the resistance to flow or pressure drop between the high pressure chamber 125 and the intermediate chamber 211, thereby assuring action of the valve member biasing spring 201 to effect displacement of the valve member lg3 to its fully open position.
The fluid pressure actuated ~otor L3 ~lso includes means responsive to piston movement minimizing the volume of the high pressure chamber 125 for discontinuing communication between the low and high prescure chambers 123 and 125, respectively, so as to ~043~
thereby permit the creation o~ fluid pressure differential between the low and high pressure chambers 123 and 125 by the fluid pressure differential creating means and thereby also to ef~ect dlsplacement of the motor piston 127 in the direction minimizing the volume of the low pressure chamber 123 and maximizing the volu~e of the high pressure chamber 125. While other arrangements can be employed, in the illustrated construction, such means comprises a pluraLity of studs or posts 221 which extend upwardly from the intermediate partition or wall 25 toward the valve member 193 and through the open valve cage 135 for engagement with the valve member 193 to ~eat the valve member 193 in the closed position as the motor piston 127 approaches the position minimizing the volume of the high pressure chamber 125.
Thus, in operation, the peesence of alternating high and low pressures in the conduit system 161 causes (assuming the valve member 193 to be in the closed position) buildup and maintenance of higher pressure in the relatively high pressure chamber 125 and reduction and maintenance of low pressure in the low pressure chamber 123. The pressure differential thus created causes displacement of the movable wall 121, including the motor piston 127, against the action of the motor piston biasing spsing 141, to the position minimizing the voLume of the low pressure chamber 123. As the motor piston 127 approaches the position minimizing the volume of the low pressure chamber 123, the valve member biasin~
spring 201 serves to open the motor piston port 191 by displacing the valve member 193 to the open position 1;~04358 and thereby to reduce or minimize the pressure differential and permit displacement of the movable wall 121 by action of the biasing spring 141 to the posi~ion minimizing the volume o~ the high pressure chamber 125. During such movement, and in the absence of a pressure differential, the valve member 193 remains in the open position under the action o~ the valve member biasing spring 201.
Upon approach o~ the movable wall 121, including the motor piston 127, to the position minimizing the volume o~ the high pressure chamber 125, the studs 221 engage the valve member 193 to cause movement thereof to the closed position. With the motor piston port 191 thus closed, the pressure differential is again created and the movable wall 121 is again displaced in the opposite direction to commence another cylce of operation. As the fuel pumping 41 and the oil pumping plunger 91 have common movement with the motor piston 127, the fluid actuated motor 13 causes reciprocation of these components at a frequency less than the frequency exciting the motor 13, i.e.~ less than the rate of alternation of the high and low pressures in the source.
Preferably, means are provided ~or selectively adjusting the discharge rate o~ the oil pumping means 17, notwithstanding displacement of the oil pumping plunger 91 through a generally constant stroke. While various other arrangements can be employed, in the illustrated construction, such means comprises a subchamber 231 which extends ~ro~ the oil pumping chamber 93 and which includes therein a ~loating piston 233. A suitable seal 235 is provided between the ~20435~
floaeing piston 233 and the wall o~ the subchamber 231.
The floating piston 233 includes, at the outer end thereof, a portion 237 which extends outwardly of the subchamber 231 and which is engaged by a cam 239 which is connected by a suitable linkage 241 shown in dotted outline to the engine throttle 243 and which is, accordingly, selectively positionable in accordance with selective positioning of the engine throttle 243.
The cam 239 thus variably restricts outward movement of the floating piston 233 so as to thereby control the effective pumping stroke of the oil pumping plunger 91.
A more detailed description of the arrangement for varying the discharge rate of the oil pumping means 17 can be found in my co-pending Application Serial No.
324,145 which is incorporated herein by re~erence.
The combined fuel and oil pumping device 11 can be mounted to the block of the two-stroke engine 8 so as to afford immediate connection to the engine crankcase 67 and can be connected to remote sources o~
oil and fuel. Alternately, if desired, the combined fuel pump and oil pump 11 can be located at a remote location more or less adjacent to or with the sources of fuel and oil and a conduit (not shown) can extend between the crankcase 67, or other source of alternating high and low pressures, and the combined fuel and oil pumping device 11.
Shown in Fig. 2 is another embodiment of a combined fuel and oil pump 301 in accordance with the invention. The construction shown in Fig. 2 is generally identical to that shown in Fig. 1, and the same reference numeral have applied for like components, except for the arrangement for insuring ~043~
full opening of the valve member 193 and the arrangement for varying the amount o~ oil ~low and the oil discharge arrangement.
With respect to the arrangement or means ~or insuring full opening movement of the valve member 193 in response to approach o~ the motor piston 127 to the posi~ion minimizing the volume o~ the low pcessure chamber 123, in the construction illustrated in Fig. 2, the rings 213 and 215 have been omitted, thereby also omitting provision of the intermediate chamber 211.
Instead, there is provided a member or post 302 which ~ixedly depends downwardly from the top housing wall 23 in position for engaging the valve member 193 as the movable wall 121 minimizes the volume o~ the low pressure chamber 123. Such engagement causes "cracking" or slight openinq of the port 191, thereby somewhat diminishing the pressure dif~erential across the movable wall 121. Such diminishment of the pressure differential facilitates immediately subsequent operation o~ the poppet valve member biasing spring 201 to displace the valve member 193 so as to fully open the port 191 and thereby to substantially eliminate the pressure differential and obtain wall movement in the direction minimizing the volume of the high pressure chamber 125 under the action of the movable wall biasing sprinq 141. I~ is also noted that the post 302 serves to stabilize or locate the upper end of the poppet valve member biasing spring 201.
In the embodiment shown in Fi~. 2, the oil pumping arrangement includes an oil pumping piston 303 which deines, in part, a variable volume oil pumping chamber 393. The oil pumping piston 303 i5 slidably i21)43SB
engaged by the movable element 91 by means of an upper end 305 of the piston 303 being located in an enclosed central chamber 307 in the movable element 91. A mid portion 309 of the piston 303 extends outwa~dly Oe the chamber 307 through an openinq 311 and connects the upper end 305 of the piston 303 to a lower portion 313 in tbe cylindrical space 87. The upper end 305 of the piston 303 is larger ~han the opening 311 so when the movable element 91 moves upwardly, the piston 303 moves with the movable element 91. Seal means 315 are provided above a lower end 317 of the piston 303 and between the lower portion 313 of the piston and the wall of the cylindrical space 87. The location of the seal means 315 permits the lower end 317 of the piston to extend below the valve inlet 101 and outlet 319.
In the embodiment, the oil pumping means 17 includes a valved outlet 319 which extends coaxially with the valved inlet 101 but on ~he opposite side of the cylindrical space 87. The outlet 319 includes a one way check valve 321 and affords outflow of oil to the conduit 63 for feeding the oil to the carburetor 65.
In the embodiment shown in Fig. 2, the means for selectively adjusting the discharge rate of the oil pumping mean~ includes an adjustable stop 323 which defines, in part, the oil pumping chamber 393. The adjustable stop 323 is located in the cylindrical space 87 below the inlet 101 and outlet 319. A suitable seal 325 is provided beSween the adjustable stop 323 and the wall of the cylindrical space B7, and ~ portion 327 of the adjustable stop above the seal 325 has a diameter les than the diameter of the cylindrical space 87 to permit the upper portion 327 of the adjustable stop to extend above the inlet 101 and outlet 319. The lower end o~ the adjustable stop 323 includes a portion 329 which extends outwardly of the cylindrical space 87 and which is engaged by the cam 239. The cam 239 operates a~ previously described.
The oil pumping means also includes biasing mean~ for biasing the oil piston 303 toward the adjustable stop 323. The biasing means comprises a spring 331 between the upper end 305 of the piston and the movable element 91 in the central chamber 307.
In operation, as the movable element 91 moves downward, the oil piston 303 move~ downwardly an equal distance. The biasing means or spring 331 i5 preloaded so that it will not deflect due to either oil pump pressure or seal friction. As the piston 303 moves downwardly, the oil pumping chamber 393 will be reduced in volume and will force oil out through the valved outlet 319. However, when the oil piston 303 contacts the adjustable stop 323, it will move no further and the remaining stroke of the movable element 91 will be taken up or lost by deflecting the biasing means or spring 331. The location of the adjustable stop 323 will, ~herefore, vary the volume o the oil pumping chamber 393 and the amount of oil pumped by the pumping means.
Shown in Fig. 3 is still another embo~i~ent of a combined ~uel and oil pump 401 which is associated with the internal combustion engine 8 and which embodies various of the ~eatureR of the invention. The construction shown in Figure 3 is generally identical to the construction shown in Figure 2 and the same reference numerals have been applied for like ~2043S~
components, except that the ~uel pumping arrangement has been slightly ~odified, except that the oil pumping arrangement has been modified to provide for variation in the output of the oil pump in accordance with engine speed without use of a ~ovable part 239 or element 323 and associated linkage, and except that th~ one-way pressure-regulating valve 177 has been omitted and the stroke of the motor piston 127 varies in accordance with engine speed. In this last regard, the poppe~
valve biasing spring 201 has a spring rate which serves to open ~he port lgl prior to the full stroke of the motor piston 127 when the engine 8 is operating at low speed and which serves to open the port 191 upon completion of the full stroke of the motor piston 127 when the engine 8 is operating at high speed.
More particularly, as is well known, in a two-stroke engine, such as the engine 8, movement of the piston relative to the cylinder and crankcase 67 serves to produce in the crankcase, cyclical conditions of relatiYely high and low pressures defining a crankcaee pressure amplitude which varies in accordance with engine speed, i.e., which increases ~ith engine speed. A~, for example, when engine operation is at idle or low speed, the pressures in the crankcase can vary fro~ about +3 psi to about -3 psi, thus providing a crankcase pressure amplitude of 6 p5i. Also, for example, when operating at high engine speed, the pressure in the crankcase can vary fro~ about ~S psi to -6 p3i, or from about +10 psi to about -1 psi, thus providing a crankcase pressure amplitude of 11 pSi.
Under operating conditions, because of the connec~ion of the crankcase 67 to the low and high ~2043~i~
pressure chambers 123 and 125, respectively, and the one-way check valves 169 and 171, the pressure conditions in the low and high pressure chambers 123 and 125, re~pectiveLy, rapidly reflect the pressuces in the crankcase 67 an provide a pressure differential acros~ the movable motor pi~ton 127, i.e., between the low.~nd high pressure chambers 123 and 125, respectively, which pressure differential has an amplitude approxi~ating the crankcase pressur~
amplitude.
The poppet valve bia~ing spring 201, as already indicated, has a spring rate such that partial movement of the motor piston 127 between the positionq causing minimum volume o~ the low and high pressure chambers 123 and 125, respectively, will cause such contraction o~ the poppet valve bia ing spring 201 as to overcome the force on the valve member 193 occurring in response to the pressure differential when the engine 8 i5 operating at low speed. However, the spring ra~e is such that, whenever the engine 8 operates a~ high speed, the force created by the pressure differential is sufficiently great to provide greater travel or full travel of the movable wall 121 or motor piston 127 prior to opening of the port 191~
As a consequence, the mator piston 127 is provided with a stroke which varies with engine speed, i.e., is provided with a stroke which increase in length with engine speed.
The fuel pumping arrangement employed in ~he construction shown in Fig. 3 varies from that sh~wn in Figs. 1 and 2 by placing the valved fuel inlet 51 in communication with the lower chamber 47 (which is, of course, not vented). In addition, the fuel pumping piston 39 is provided wit~ one or more apertures 411, each having associated therewith a one-way check valve member 413 affording flow from the lower chamber 47 to the upper chamber 45 and preventing ~low ~rom the upper chamber 45 to the lower chamber 47. The stroke of fuel pumping member or piston 39 is identical to the stroke of the motoc piston 127 and hence the amount of fuel pumped will vary in accordance wi~h engine speed, i.e., will increase with increa ing engine speed.
If desired, a fuel pump construction identical to that shown in Figs. 1 and 2 could aLso be employed.
The oil pumping arrangement differs from the construction shown in Figs. 1 and 2 in that the amount of oil pumped is automatically varied in accordance with engine speed and in that, due to a lost-motion connection between the motor piston 127 and the oil pumpinq piston 303, oil pumping does not occur until after a first engine speed level, which can be intermediate the low and high engine speeds, and which, above the first enqine speed level, increases wi~h increa~ing engine speed.
In thi3 last regard, the oil pumping piston 303 is connected to the motor piston 127 to provide for common movement therewith during a portion o~ the motor piston stroke and to provide for lost-motion during another portion of the motor piston 127 stroke. In this regard, the upper end of the oil pumping piston 303 i~ provided with an axial recess or bore 415 which is defined, at the upper end thereof, by an internal annular flange 417 deining an opening 419, and the ~204æ~
motor piston 127 is provided with an extension 421 which projec~s through the opening 419 provided by the annualar ~lange 417 and include~, at the lower end, an enlarged head 4~3 which cannot pass through the opening 419 defined by the annualar flange 417. Thus, initial upst~oke movement o~ the motor piston 127 from the positio~ minimizing the volume of the high pressure chamber 125 does not cause accompanying movement of the oil pumping piseon 313. However, before the motor piston 127 raaches the position minimizing the volume of low pressure chamber 123, the head 423 engages the flange 417 to cause common movement of the oil pumping piston 303 with the motor piston 127. Initial downstroke motion of the motor piston 127 does not cause the oil pumping piston movement until the head 423 engages the blind end of the recess or bore 415.
Thus, oil pumping operation occurs only at the top of the up~trok~ of the motor piston movement and at the bottom of the downstroke o~ the motor piston movement.
Accordingly, the oil pumping arrangement disclosed in FigO 3, provides for little or no pumping at low engine speeds and for increasing oil pumping with increasing speeds above low engine qpeed.
As in the construction shown in Fig. 2, the oil d$scharge from the output 319 is conveyed to the fuel discharge conduit 63 for mixture therewith.
However, if desired, the discharged oil could be conveyed for mixture with the ~uel in either the ueeer chamber 45 or in the lower cha~ber 47.
Various of the featureq of the invention are set forth in the following claims.
Claims
1. An oil pump including oil pumping means comprising a movable element reciprocal through a given distance for pumping oil in response to reciprocation of said element, a variable volume oil pumping chamber including oil inlet means and oil discharge means, and means for varying the output of said pumping means notwithstanding the reciprocation of said element through said given distance, said output varying means including an oil piston defining, in part, said oil pumping chamber, and means connecting said element and said piston for displacing said piston in response to movement of said element and for permitting lost motion between said element and said piston.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000474596A CA1204358A (en) | 1981-10-23 | 1985-02-19 | Combined fluid pressure actuated fuel and oil pump |
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US314,224 | 1981-10-23 | ||
| US06/314,224 US4473340A (en) | 1981-10-08 | 1981-10-23 | Combined fluid pressure actuated fuel and oil pump |
| US06/410,497 US4539949A (en) | 1981-10-08 | 1982-08-23 | Combined fluid pressure actuated fuel and oil pump |
| CA000413422A CA1196823A (en) | 1981-10-23 | 1982-10-14 | Combined fluid pressure actuated fuel and oil pump |
| CA000474596A CA1204358A (en) | 1981-10-23 | 1985-02-19 | Combined fluid pressure actuated fuel and oil pump |
| US410,497 | 1995-03-24 |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000474596A Division CA1204358A (en) | 1981-10-23 | 1985-02-19 | Combined fluid pressure actuated fuel and oil pump |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000474596A Division CA1204358A (en) | 1981-10-23 | 1985-02-19 | Combined fluid pressure actuated fuel and oil pump |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1204358A true CA1204358A (en) | 1986-05-13 |
Family
ID=27167292
Family Applications (4)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000474594A Expired CA1204354A (en) | 1981-10-23 | 1985-02-19 | Combined fluid pressure actuated fuel and oil pump |
| CA000474595A Expired CA1205707A (en) | 1981-10-23 | 1985-02-19 | Combined fluid pressure actuated fuel and oil pump |
| CA000474596A Expired CA1204358A (en) | 1981-10-23 | 1985-02-19 | Combined fluid pressure actuated fuel and oil pump |
| CA000474597A Expired CA1204355A (en) | 1981-10-23 | 1985-02-19 | Combined fluid pressure actuated fuel and oil pump |
Family Applications Before (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000474594A Expired CA1204354A (en) | 1981-10-23 | 1985-02-19 | Combined fluid pressure actuated fuel and oil pump |
| CA000474595A Expired CA1205707A (en) | 1981-10-23 | 1985-02-19 | Combined fluid pressure actuated fuel and oil pump |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000474597A Expired CA1204355A (en) | 1981-10-23 | 1985-02-19 | Combined fluid pressure actuated fuel and oil pump |
Country Status (1)
| Country | Link |
|---|---|
| CA (4) | CA1204354A (en) |
-
1985
- 1985-02-19 CA CA000474594A patent/CA1204354A/en not_active Expired
- 1985-02-19 CA CA000474595A patent/CA1205707A/en not_active Expired
- 1985-02-19 CA CA000474596A patent/CA1204358A/en not_active Expired
- 1985-02-19 CA CA000474597A patent/CA1204355A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CA1204355A (en) | 1986-05-13 |
| CA1205707A (en) | 1986-06-10 |
| CA1204354A (en) | 1986-05-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |