US3849029A

US3849029A - Combination engine operated fuel pump and air pump

Info

Publication number: US3849029A
Application number: US00311464A
Authority: US
Inventors: J Creager; R Taylor
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1972-12-04
Filing date: 1972-12-04
Publication date: 1974-11-19
Anticipated expiration: 1991-11-19
Also published as: CA993721A

Abstract

In the preferred form of the invention there is shown an air pump or air compressor having a housing attached to and driven by the action of a diaphragm fuel pump of the type well known in the art. The compressor is adapted to be connected to the fuel pump body which in turn is connected to the engine block in an area that will give ready access to the engine cam. Both the fuel pump and air compressor are driven by the fuel pump rocker arm through the engine cam whereby the rocker arm reciprocates a piston within an oil filled cylinder in the air compressor. A diaphragm is in turn operated through the reciprocation of the piston and the action of the oil in the cylinder, to draw air into and discharge air from a pumping chamber beneath the diaphragm.

Description

United States Fate/m [1 1 Creager et a1.

FORElGN PATENTS OR APPLICATIONS 2/1948 Italy 417/388 [451 Nov 19, 1974 272,374 6/1927 Great Britain 417/385 Primary Examiner -Williatn 1... Freeh Attorney, Agent, or Firm-Peter A1 Taucher In the preferred form of the invention there is shown an air pump or air compressor having a housing attached to and driven by the action of a diaphragm fuel pump of the type well known in the art. The compressor is adapted to be connected to the fuel pump body which in turn is connected to the engine block in an area that will give ready access to the engine cam. Both the fuel pump and air compressor are driven by the fuel pump rocker arm through the engine cam whereby the rocker arm reciprocates a piston within an oil filled cylinder in the air compressor. A diaphragm is in turn operated through the reciprocation of the piston and the action of the oil in the cylinder, to draw air into and discharge air from a pumping chamber beneath the diaphragm.

ABSTRACT 3 Claims, 3 Drawing Figures COMBINATION ENGINE OPERATED FUEL PUMP AND AIR PUMP This invention relates to a combination fuel pump and air compressor and more particulary to an oil filled compressor integral with a fuel pump which is operated by the fuel pump rocker arm. An oil pump on one side of a diaphragm acts to draw air into and pump air out of a pumping chamber. Prior art combination pumps or compressors generally show the combination of a fuel pump and low pressure vacuum compressor type pump but do not show a fuel pump combined with a high pressure compressor pump. Similar prior art devices do not include an oil filled cylinder on one side of the diaphragm. This is evidenced by. the prior art U.S. Pat. Nos. to Babbich et al, 2,139,346 and 2,189,526.

Under circumstances where the oil piston is reciprocated at high speeds it is necessary to provide a pumping cavity that allows for unrestricted high speed movement of the diaphragm in the air pump chamber. Additionally, the diaphragm under high oil pressure must move smoothly and completely in and out of the pump cavity to provide maximum air in and out of the pumping chamber though there is a very short distance and minimal movement and travel by the diaphragm. This action provides maximum compression with a very short stroke.

Accordingly, an object of the present invention is to provide an air compressor driven by the rocker arm of a fuel pump.

Another object of the present invention is to combine bolts through holes 17 or by any other commonly used fastening means such as welding, or the like.

Rocker ann 18 having an auxiliary wear pad 20 thereon rides on cam surface 22 on the engine cam shaft. The operation of the rocker arm on the engine cam as used to drive pumps is well known in the prior a fuel pump and air compressor to eliminate the need for a rocker arm and cam drive means, and a mounting area on the engine block that would be required for a separate cam driven air pump.

Another object of the present invention is to provide an air compressor that is self-priming and which prevents aeration of oil on the oil side of the diaphragm to improve the operating characteristics of the compressor.

Another object of the invention is to provide an im proved air compressor that is adapted to be operated by an engine cam and which includes an oil filled reservoir or sump region.

These and other objects and advantages of the present invention willv be apparent from the drawings in which:

FIG. 1 shows the combination fuel pump and compressor having a common rocker arm driven by the engine cam.

FIG. 2 is a sectional view of the compressor portion of the pump shown in FIG. 1.

FIG. 3 is a sectional view of a modified version of the bottom portion of the pump as shown in FIG. 2.

Referring now to FIG. 1, the combination fuel and air compressor is shown at 10 and includes a fuel pump 12 and air compressor 14. The fuel pump is of the diaphragm type well known in the prior art with the fuel pump per se not being considered as part of the invention other than in the use of a common rocker arm to operate both the fuel pump and air compressor. It is understood that either the fuel pump or air compressor could work independently of each other, but in such a configuration they would each require a separate rocker arm and cam as well as separate mounting areas on the engine block. The combination pump is attached to the engine block by means of a-flange l6 and art as shown by the referenced prior art patents.

Referring to FIG. 2 the air compressor portion 14 of the pump comprises a housing or body member 24 that is attached to a flared flange 26 on the fuel pump body 12 by means of a crimped or turned over portion 28. It is understood that other means of attaching the air compressor body to the body of the fuel pump such as bolts, screws, welding and the like could also be used. Body 24 could also be made integral with fuel pump body 12. Within housing 24 is a diaphragm 30 that is held in position in a diaphragm retaining area 32 on body 24 which is an outturned or flared portion on the housing generally U-shaped and integrally formed therewith. The diaphragm is held in a sealed position in retaining area 32 by flared or flanged end portions 33 on

cylinder

34 and 35 on valve retaining housing member 36. Below the flared end 35 on valve retaining housing member 36 there is a gasket 38 to provide a seal between the valve housing member and the diaphragm retaining area 32. Body member 24 and the valve housing 36 attached thereto, as well as the upper crimped portion 28 and diaphragm 30 form an oil reservoir 29 within the body member 24.

Cylinder 34 includes an elongated, tubular extension 40 integral with flared ends 33 that receives the sidewalls 42 of slidably piston 44. Piston 44 has a -U-shaped flange at the upper end as at 46 to retain end plate 48 having a plurality of openings 50 therein. Piston 44 also has a plurality of openings as at 51 adjacent the U- shaped flange 46. The bottom or lower plate 52 of piston 44 is integral with the side walls of piston 42 and has a plurality of holes or openings 54 therein. It is understood that this lower plate could be made as a separate member and joined to the piston side wall in any convenient means of attachment; Beneath lower plate 52 and above the diaphragm 30 there is an oil cavity 53 formed by the shape of the bottom of-plate 52 and the bottom or flared end 33 of tubular extension 40. The size and shape of cavity 53 is determined by the pressure that is necessary to act on diaphragm 30 to move said diaphragm into the bottom cavity so that it will be in complete conformity with the bottom cavity to give maximum pressure output.

Adjacent the bottom plate 52 is a valve member 56 that closes the plurality of holes 54. Valve member 56 is seated on upturned seat portions 58 on plate 52 by means of spring 60. Retained within valve member 56 by a spring 57 is a second valve member 62 that closes inlet port 64.

Piston member 44 is actuated by the engine cam 22 through rocker arm 18, which is attached to a central shaft member 66 that connects the fuel pump operating- Valve housing 36 contains an intake valve 74 and an exhaust valve 76. The valves are generally of the type well known in the art. On the intake stroke, or upward stroke of the piston, valvemember 75 operates against a spring 77 to allow air into cavity 78 located beneath diaphragm 30. Upon the downward or exhaust stroke of piston 44, exhaust valve member 79 operates against spring 81 to exhaust air from cavity 78.

FIG. 3 shows another embodiment of the invention similar to the embodiment shown in FIG. 2. Body member 80 of the compressor is formed integral with the fuel pump 12. The bottom or lowermost portion of body 80 has a flange member 82 with steps 84 therein for retaining and aligning diaphragm 86, and flared ends 87 on tubular extension 88 and gasket 90. Diaphragm 86, flared end 87 on tubular extension 88 and gasket 90 are secured to and held in a sealed relationship within a body cavity 92 by a valve housing or cover plate 94. Valve housing 94 is held in position on body member 80 by a crimped flange 96. It is understood that any convenient locating means or means of attachment could also be used. Tubular extension 88 receives a sidewall 98 of piston member 100. The piston member 100 also has flared end as at 102 at the upper end thereof to retain an end plate 104. End plate 104 has a plurality of openings 106 therein. Piston 100 also has a plurality of openings 108 adjacent the flared end 102 and has an integral bottom or lower plate 110 having a single enlarged hole 112 therein. 7

Located within piston 100 is a valve member 114. Valve member 114 comprises a spring biased shaft 116 having a stepped disc shaped closure member 118 that closes an opening in the center of a rubber disc or plate member 119. An upper head portion 120, also disc shaped, is held in locked position on shaft 116 by upending the shaft as at 122. Around shaft 116 is a spring 124 that bottoms on a disc closure member 126. Spring 124 is biased upwardly by the disc 126 against the head member 120 to close the hole in rubber disc 119. Disc member 126 is biased by spring 128 downwardly against the lower plate 110 to close the opening 112 by seating on plate 110 and against disc 119. The piston 100 is also biased in an upward position or direction by spring 130 and is driven in a downward direction against the spring bias by drive member 132, similar to that of FIG. 2, whereby the drive member is attached to a rocker arm 134 in the same manner as previously described in relation to FIG. 2. In addition, the drive member 132 has a spring 136 that acts on the end plate 104 to provide additional lift or thrust upwardly of the rocker arm 134 to assure a positive contact with the rocker arm and cam.

In operation, the two different air compressors as shown in FIGS. 2 and 3 are basically the same. There fore, it is understood that the description of the operation of the air compressor shown in FIG. 2 will suffice to explain the operation of the air compressor shown in FIG; 3. The primary difference between the two embodiments is in the valving mechanism in the bottom plate. In the operation of the air compressor, oil is initially added to the oil reservoir 29 through the rocker arm opening and the oil is then generally replenished by'oil splashing from the crankcase into the rocker arm opening into the reservoir 29. If desired, a filler hole could also be added in housing 24.

.As cam 22 reaches its highest point, drive member 70 through rocker arm 18 moves piston 44 downwardly,

through seat portion 58 and the holes in the bottom plate 54. When the piston reaches the end of or lowermost point of the downward stroke, the rocker arm and drive member 70 through the action of return spring 72 moves the piston in an upward direction. As the piston moves upwardly, the volume in cavity 53increases thereby creating a vacuum therein. The diaphragm at this time also moves upwardly into cavity 53 to an uppermost or highest cavity position as permitted by the shape of tubular extension 40 and the bottom plate 52 that act to form the cavity shape. As the piston continues to move in an upward direction valve 62 opens, when the vacuum in the chamber above diaphragm 30 becomes great enough to overcome the spring force exerted by spring 57, acting on the valve disc member 62. When the valve opens oil enters the cavity 53 through holes 54. The action of the oil through the valves and the respective holes above the cavity prevents aeration on the oil side of the diaphragm. This action is the intake stroke of the compressor wherein air is pulled in through valve 76 into cavity 78 below the diaphragm in preparation for the next exhaust stroke. The stroke is approximately 0.380 in length at a pressure of psi creating a pumping volume of 65 in/- min at 1,000 rpm. Y

The air compressor is generally used in air bag suspension systems on automobiles, these systems not making up part of this invention. The air bag system generally contains a maximum pressure limiting device and upon the air bag reaching that pressure a bypass valve is opened so that air pumped by the compressor is pumped to the atmosphere until the air bag requires additional air. The pump is a continuous pump that operates when the automobile engine operates.

Although our invention has been described in terms of certain specific embodiments, it is to be understood that other forms may be adopted within the scope of the invention.

We claim:

1. In a combination air compressor and fuel pump assembly of the type having a common rocker arm for driving the fuel pump and air compressor the improvement comprising: an oil filled housing adapted to be secured to the fuel pump body; a diaphragm secured within a flanged portion on said housing by a cylinder, a valve housing, a gasket, and a flanged portion on said body crimped below the valve housing and gasket; a hollow piston having top and bottom perforated end plates slidably positioned within said cylinder with said top perforated end plate being unobstructed to allow oil from the oil filled housing to enter and discharge through the perforations into and out of said piston; said cylinder, piston and the upper side of said diaphragm define an oil cavity; whereas the lower side of said diaphragm and valve housing define an air cavity; a relief valve within said hollow piston spring biased against a seat on said perforated bottom end plate to close the perforations in said end plate to prevent oil from discharging from the oil cavity during the pumping stroke; an inlet valve positioned within said relief valve that is spring biased so as to close an inlet opening in said relief valve to, along with the relief valve, prevent oil from discharging from the oil cavity during the pumping stroke and which inlet valve allows oil to enter the oil cavity from the oil filled housing through the inlet opening during the intake stroke to empty the oil cavity and thereby allow the air cavity to be filled, said valve housing having air intake and discharge valves therein to take in air through the air intake valve during the suction stroke through the discharge valve and discharge air out of the lower cavity during the pump stroke; drive means secured to a rocker arm which drive means is in contact with the top perforated piston end plate to slidably move said piston into said cylinder during the pump stroke, and spring means surrounding said cylinder which is in contact with the underside of the upper portion of said piston which spring means moves said piston out of said cylinder during the suction stroke.

2. In a combination air compressor and fuel pump assembly as set forth in claim 1; with said piston having an integrally formed perforated plate at one end, and a second separate plate held within said piston adjacent the other end by crimped means.

3. A compressor adapted to be driven by an engine cam comprising: a housing having an end connected to the engine block at a cam port therein; a diaphragm secured within a flanged portion on said housing by a cylinder, a valve housing, a gasket, and a crimped over portion on said body below the valve housing; said housing and diaphragm defining an oil filled reservoir in communication with the endine crankcase through the cam port; a piston having perforated end plates slidably positioned within said cylinder; said cylinder, piston and diaphragm define an upper oil cavity; whereas said diaphragm and valve housing define a lower air cavity; said perforated end plates on said piston permits oil from the reservoir to enter and discharge through the perforations into and out of said piston and oil cavity; a relief valve within said piston spring biased against a seat on said piston to close the perforations in one piston end plate to prevent oil from discharging from the upper oil cavity during the pumping stroke, an inlet valve within said relief valve spring biased to close an inlet opening in said relief valve to prevent oil from discharging from the upper cavity during the pumping stroke and allowing oil to enter the upper oil cavity from the reservoir through the inlet opening during the intake stroke; said valve housing having air intake and discharge valves therein to intake and discharge air into and out of the lower cavity during the respective intake and pump strokes; and drive means secured to the common rocker arm and in contact with the piston end portion opposite said diaphragm to slidably move said piston into said cylinder.