US3722209A

US3722209A - Engine-starting septem

Info

Publication number: US3722209A
Application number: US00132746A
Authority: US
Inventors: J Kaytor
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-04-09
Filing date: 1971-04-09
Publication date: 1973-03-27
Anticipated expiration: 1990-03-27

Abstract

A combination relay and check valve for use with a fluid actuated engine starting system. The valve includes a housing which contains a diaphragm connected to a valve. The valve divides the housing into inlet and outlet chambers. A lubricant reservoir is contained in the housing and means are provided to inject a charge of lubricant into the chambers when the valve is opened. Excessive pressure in the outlet chamber acts on the diaphragm to close the valve and means are provided to selectively close off the source of control pressure from the diaphragm so that the valve cannot be opened when the engine is running.

Description

United States Patent Kaytor Mar. 27,1973

[54] ENGINE-STARTING SYSTEM [75] Inventor: James Kaytor, Franklin, [11. Primary Examiner-Martin Schwadron Assistant Examiner-Allen M. Ostra'ger [73] Assignee. Olin Corporation New Haven, Attorney-Donald R. Motsko, 11. Samuel Kieser and Conn William W. Jones [22] Filed: Apr. 9, 1971 [57] ABSTRACT [2!] Appl' 132346 A combination relay and check valve for use with a fluid actuated engine starting system. The valve in- [52] U.S.Cl. ..60/6, 60/14, 60/17, cludes a housing which contains a diaphragm con- 7 123/179 F nected to a valve. The valve divides the housing into I 1 Int-CL 67/00,F0lb27/00 inlet and outlet chambers. A lubricant reservoir is Field 0f Search 123/179 contained in the housing and means are provided to 123/179 91/46; 92/154 inject a charge of lubricant into the chambers when the valve is opened. Excessive pressure in the outlet References Clted chamber acts on the diaphragm to close the valve and UNITED STATES PATENTS means are provided to selectively close off the source of control pressure from the diaphragm so that the 1,049,010 12/1912 Waugh ..91/46 valve cannot be opened when the engine is running. 1,262,864 4/1918 Stevens ..91/46X 2,931,349 4/1960 Nicolodi.... ..123/179 F 3,104,659 9/1963 Smith ..123 179 F 3,459,165 8/1969 Bender et al. ..123/179 F 5 Clams 5 D'awmg Z I I 3 x4 l4 I L a PATEMHiUmRmms 7 3,722,209

SHEET 10F 2 JAMES KAYTOR m4 INVENTOR /0 ATTORNEY fIG-Z PATENTEUmzmn 3 9 HG JAMS KAYTDR INVENTOR Y ZJMMQW ATTORNEY ENGINE-STARTING SEPTEM This invention relates to a combination relay and check valve for use with a fluid actuated system.

The valve of this invention is more particularly adapted for use with a fluid-actuated engine starting system which includes a vane motor. The vane motor is preferably of the type having a plurality of vanes mounted on a rotor, the vanes being exposed to a stream of pressurized fluid so as to cause the rotor to rotate. The vane motor is operably connected to the engine in such a way that rotation of the vane motor causes the latter to engage the engine and crank it until the engine becomes self-sustaining.

The engine starting sytems with which the valve of this invention is particularly useful generally includes a tank which contains a supply of pressurized fluid which is used to rotate the vane motor or starting unit. For purposes of economy and adaptability, the connections between the pressurized fluid tank and the starting unit may be flexible plastic or rubber tubing. Systems of this type commonly utilize a relay valve interposed between the pressurized tank and the starting unit, which valve is normally closed and can be selectively opened to feed pressurized fluid to the starting unit to actuate the latter. The system may also include a device which can be operated to fire a propellant charge to produce a volume of high pressure, high temperature combustion gases which are utilized instead of the pressurized fluid to actuate the starting unit. Metal tubing which is corrosion and heat resistant must be used to feed the combustion gases into the starting unit, and a separate check valve must be interposed between the propellant firing device and the relay valve to protect the flexible conduits and the pressurized tankfrom being exposed to the hot, corrosive combustion gases.

It has, furthermore, been found to be highly desirable to include an injector device which is selectively operable to inject a charge of lubricant into the starting unit to clean and lubricate the latter during actuation thereof. The lubricant can be in the form of diesel fuel, lubricating oil, or any other comparable liquid useful for cleaning and lubricanting. An engine starting system including a source of pressurized fluid, a relay valve, a propellant firing device, and lubricator is disclosed in patent application U. S. Ser. No. 805,325 to Lowell L. Russell and Donald E. Bender and filed Mar. 7, 1969, now abandoned.

One disadvantage found in the system having a dual capacity for actuating the starting unit, and a lubricator as described above, is that the system is undesirably complex in construction and requires a number of separate valves and subcomponents which must be packaged in a limited space while at the same time ensuring proper interaction to achieve the desired result. Such systems have proven rather complicated to install and maintain, and service in the field, rather bulky, and difficult to completely seal from the elements of weather.

A further disadvantage attendent in the prior art systems noted above relates to the accidental actuation of the starting unit when the engine is already running. Such an occurrence can seriously damage the starting unit and the engine since engagement between the two should occur only when the engine is off, and disengagement should occur when both are running at low speeds.

The valve assembly of this invention solves the above-noted disadvantages found in the prior art by providing a single valve unit which is adapted to perform a multiplicity of functions. The unit is housed in a single housing which is sealed from the surrounding environrnent to protect the various elements in the unit from weather and other external influences. The housing includes an inlet port and an outlet port which combine with a portion of the interior of the housing to define a flow path along which pressurized fluid is fed from a pressure chamber to the starting motor. A valve head and cooperating valve seat are positioned within the housing and are selectively operable to control the flow of the pressurized fluid to the starting unit. The valve head is normally biased into engagement with the valve seat so that the valve is normally closed to block the flow of pressurized fluid through the housing. A

flexible diaphragm is preferably mounted in the housing and connected to the valve head so that movement of the diaphragm results in corresponding movement of the valve head. The diaphragm is preferably arranged within the housing in such a manner that one surface of the diaphragm is exposed to pressure variations occurring in the outlet port of the housing, and the opposite surface of the diaphragm is exposed to pressure variations occurring in a control pressure chamber disposed in the housing. The fluid pressure within the control pressure chamber is selectively variable so that predetermined increases in control pressure will result in flexure of the diaphragm which in turn results in movement of the valve head away from the valve seat to open the valve and permit flow of the pressurized operating fluid from the inlet port along the flow path and through the outlet port.

The propellant firing mechanism is positioned between the outlet port and the starting unit so that when the firing mechanism is utilized to actuate the starting unit, the pressure in the outlet port of the housing greatly increases. Since one surface of the diaphragm is exposed to the outlet port the increase in pressure therein causes the diaphragm to flex and force the valve head into tighter engagement with the valve seat to prevent the hot combustion gases from passing upstream into the flexible conduits and the pressurized fluid tank. In this manner the flexible conduits and pressurized tank are protected from the harmful temperatures and corrosiveness of the combustion gases.

A second flexible diaphragm is disposed in the housing with one surface thereof exposed to a second chamber termed a condition chamber which is in communication with a source of fluid pressure in the engine. The other surface of the second diaphragm is exposed to a conduit which leads from the source of the pressurized control fluid to the control'chamber. When the engine is running, the pressure in the condition chamber rises sufficiently to flex the second diaphragm into a position which blocks the conduit against flow of the control fluid. Thus, if the control fluid source is accidently actuated to feed control fluid into the control chamber while the engine is running, the second diaphragm will prevent the control fluid from reaching the control chamber, so that the starting unit cannot be actuated by the pressurized control fluid from thetank while the engine is running. Thus a condition responsive means, which senses when the engine is running,

disables the control means from opening the valve and actuating the vane motor.

In order that the starting unit will be lubricated when it is actuated by the pressurized operating fluid, the valve head is operable connected to a lubricant injector which is actuated to inject a charge of lubricant into the fluid flow path in the housing each time the valve head moves away from the valve seat to open the valve. The injector includes a variable volume chamber disposed in the housing and means, such as a piston, operative to reduce the volume of the chamber when the valve head is moved away from the valve seat. A one way check valve is mounted in the volume-varying means, the check valve opening to permit the lubricant to flow through a conduit into the fluid flow path. Preferably, the valve head is mounted on the volume-varying means so that movement of the latter to reduce the volume of the lubricant chamber accompanies movement of the valve head away from the valve seat, and so that movement of the volume-varying means to enlarge the volume of the lubricant chamber accompanies movement of the valve head toward the valve seat.

It is, therefore, an object of this invention to provide I a valve assembly for use with a fluid flow system wherein the valve assembly functions both as a fluid relay valve and a reverse flow check valve.

It is a further object of this invention to provide a valve assembly of the character described which further functions as a lubricant injector when operating to permit fluid flow in a downstream direction.

It is yet another object of this invention to provide a valve assembly of the character described wherein actuation thereof is achieved by means of varying a control fluid pressure.

It is yet a further object of this invention to provide a valve assembly of the character described further having condition responsive means for preventing variation of the control fluid pressure upon attainment of the predetermined condition.

It is still another object of this invention to provide a valve assembly of the character described which is contained in a single housing for ease of assembly and maintenance.

It is an additional object of this invention to provide a fluid actuated engine starter incorporating a single valve assembly operative to regulate flow of the operating fluid, prevent backward flow of high pressure, hot combustion gases, and inject a charge of lubricant into a stream of operating fluid.

These and other objects and advantages of the invention will become more readily apparent from the following detailed description of a preferred embodiment of the invention, and the accompanying drawings, in which:

FIG. 1 is a schematic diagram of an engine starting system incorporating the valve assembly of this invention;

FIG. 2 is a sectional view of the valve assembly of this invention wherein the valve is shown in its closed position;

FIG. 3 is a sectional view similar to FIG. 2 but showing the valve assembly in its open position wherein the injector has been actuated to feed a charge of lubricant into the fluid flow path;

FIG. 4 is a sectional view similar to F IG. 2, but showing the condition responsive diaphragm in position to block the passage of control pressure to the control chamber so that the valve cannot be opened; and

FIG. 5 is a cross-sectional view of the valve head portion of the lubricator injector taken along line AA of FIG. 4 showing the passages through which the lubricant flows by the valve head when the latter is removed from contact with the valve seat.

Referring now to FIG. 1, an engine starting system is shown schematically. The system includes a tank 2 in which is stored pressurized operating fluid which can be used to rotate the vanes in a conventional vane-type starting motor 4. A line 3 is connected to a compressor (not shown) to maintain the fluid pressure in the tank 2. The starting motor 4 includes a gear 6 which is mounted on a rotatable shaft (not shown) and which, when actuated, is moved axially into engagement with a complimentary gear 8 which is mounted on a shaft 10. Rotation of the shaft 10 turns the engine 12 over to crank the latter. The starting motor and the manner in which it operates to crank the engine are conventional and form no independent part of this invention. A flexible rubber or plastic conduit 14 is connected to the pressurized operating fluid tank 2 and extends therefrom to a valve housing 16.

A propellant charge firing device 18 of conventional construction is positioned downstream of the operating fluid tank 2 and is connected to a metal conduit 20 adapted to conduct high pressure, high temperature combustion gases generated when a charge of propellant is fired in the device 18. The conduit 20 is in turn connected to a similar metal conduit 22 which extends between the housing 16 and the starting motor 4'. It is thus apparent that either the pressurized operating fluid from the tank 2 or combustion gases from the device 18 may be used to actuate the starting motor 4.

A tank 24 which contains a supply of lubricant is connected by means of a flexible conduit 26 to the housing 16. The tank 24 can be the fuel tank for the engine 12, in which case the lubricant will be diesel fuel, or the tank 24 can be a separate container for diesel fuel or some other lubricant, such as oil, or the like. A vent cap 28 is preferably mounted on the tank 24 so that the supply of lubricant will be under at least atmospheric pressure. Alternatively, the tank 24 could be pressurized so as to further put the lubricant under pressure.

A container 30 is connected to the housing 16 by means of a flexible conduit 32. A valve 34 is interposed between the container 30 and the conduit'32, and the valve 34 can be manually operated by a remote actuator 36. The container 30 contains a supply of pressurized control fluid which can be fed'into the housing 16 to selectively control actuation of the valve disposed therein in a manner more particularly set forth hereinafter. A conduit 38 interconnects a source of positive fluid pressure within the engine 12 with the housing 16 to permit the engine pressure to prevent actuation of the valve disposed in the housing 16 in a manner more clearly set forth hereinafter. The source of engine pressure can be engine oil pressure, fuel line pressure, brake line pressure, or any other suitably and convenient pressure source that is providing a constant pressure while the engine is a Referring now to FIG. 2, the housing 16 includes a lower member having a threaded inlet port 42 and a threaded outlet port 44. The operating fluid conduit 14 is connected to the inlet port 42 and the metal conduit 22 is connected to the outlet port 44. An aperture 46 disposed in an internal wall 48 in the member 40 defines, along with the inlet 42 and outlet 44, a fluid flow path through the lower member 40 along which flow path a stream of pressurized operating fluid is directed from the tank 2 to the starting motor 4. A crown 50 is mounted on the top of the lower member 40 by means of a plurality of bolts 52 (one of which is shown), and a flexible diaphragm 54 is sandwiched between opposite faces of the lower member 40 and the crown 50 to seal off the upper margin of the flow path. It is noted that the diaphragm 54 can be made of heat and corrosion resistant plastic material or can be formed from a thin sheet of metal resistant to heat and corrosion. The inner surface 56 of the crown 50 is recessed to form a chamber 58 between the surface 56 and the flexible diaphragm 54. The top surface of the crown 50 is also recessed as at 60 with a first passage 62 leading from the recess 60 to the chamber 58, and a second passage 64 leading from a threaded port 66 to the recess 60. The threaded port 66 is connected to the control pressure conduit 32 so 'that pressurized control fluid can be fed through the port 66 and the

conduits

62 and 64 into the control chamber 58.

A cap member 68 is secured to the top of the crown 50 by means of a plurality of bolts 70 with the inner surface of the cap 68 being recessed as at 72. A flexible diaphragm 74 is sandwiched between the cap 68 and the crown 50 and operates to seal the top of the recess 60 from the atmosphere. The diaphragm 74 and the cap recess 72 combine to provide a chamber 76 which communicates with a threaded port 78 which is connected to the conduit 38 that extends from the source of positive engine pressure. It is noted that an upwardly protruding annular bead 80 is formed in the upper crown recess 60, the head 80 completely surrounding the opening of the passage 64. The diaphragm 74 is normally positioned as shown in FIG. 2, e.g., with its lower surface spaced upwardly away from the bead 80 so that pressurized control fluid can flow from the port 66 to the control chamber 58. This normal positioning of the diaphragm 74 occurs when the engine 12 is not running so that there is no positive pressure in the chamber 76.

The lower edgeof the aperture 46 is tapered to form a valve seat 82, and a valve head 84 of suitable sealant material is mounted on a movable member, such as a piston 86, which is positioned within the housing 16 for reciprocating movement toward and away from the valve seat 82. A spring member 87 contacts the piston 86 and biases the latter and the valve head 84 toward the valve seat 82. A plug 88 is threaded into the bottom wall of the lower member 40, the plug 88 having a well 90 into which the piston 86 extends. The piston 86 includes an external groove 92 in which is disposed a sealing ring 94 which engages the side wall of the well 90. Thus a variable volume chamber 96 is defined by the piston 86 and the well 90, reciprocating movement of the piston 86 within the well 90 being operative to increase or decrease the volume of the chamber 96.

The chamber 96 communicates with a port 98 having a threaded portion 100 which is connected to the lubricant conduit 26. An inwardly extending flange 102 is positioned in the port 98 to define therein a valve seat 104. A valve head 106 of suitable material is slidably mounted in the port 98 and is biased toward the valve seat 1 by a light spring 108. The sealing end of the valve head 106 is conically shaped as at 110 and there are grooves 112 cut into the sides of thevalve head 106 to permit fluid to flow by the head 106 when the latter is displaced from the valve seat 104. FIG. 5 shows how the grooves 112 form passages 114 with the side wall of the port 98. As shown in FIG. 2, the valve head 106 is in sealing engagement with the valve seat 104 so that lubricant cannot flow through the port 98.

A connector 116 is threadedly connected to the piston 86 at one end, and is secured at the other end to the diaphragm 54 by means of a pair of plates 118 and a bolt 120. The connector 116 provides a link through which movement of the diaphragm 54 can be imparted to the piston 86 and valve head 84, and vice versa.

A passage 122 extends longitudinally through the piston 86, the passage 122 opening at one end into the lubricant chamber and communicating at its other end with a further passage 124 extending through the connector 116 and opening out into the operating fluid flow path downstream of the valve head 84. A valve seat 126 is positioned in the passage 122 as is a movable valve head 128 which is biased by a light spring 130 toward the valve seat 126. The operation of the vlave head 128 is identical to the operation of the valve head 106 described in detail above.

The assembly operates in the following manner. The spring 87 biases the piston 86 and the valve head 84 toward the valve seat 82 so that the valve is normally closed and operating fluid cannot flow from the inlet 42 along the flow path and through the outlet 44 to the starting motor. It is also apparent that the lubricant chamber 96 will normally be at its greatest volume. Also the diaphragm 54 will be deflected upwardly as shown in FIG. 2. If the operator desires to actuate the starting motor 4 by firing a propellant charge in the device 18, the pressure from hot combustion gases in the outlet port 44 will greatly increase, thus forcing the I diaphragm 54 to flex upwardly even more tightly. The upward flexure causes the valve head 84 to be drawn more tightly against the valve seat 82 thus offsetting the high pressure acting directly on the valve head face which would otherwise tend to force the valve head 84 to move away from the valve seat 82. In this manner, high pressure, high temperature combustion gases are prevented from flowing upstream into the flexible conduit 14 and tank 2. If the operator desires to start the engine 12 by actuating the starting motor 4 with pressurized operating fluid from the tank 2, the appropriate manipulation of the actuator 36 is made to open the valve 34 and permit pressurized control fluid to flow from the tank 30 into the port 66 in the housing 16. The pressurized control fluid flows through the

passages

64 and 62 and into the control chamber 58 wherein it acts upon the diaphragm 54 to deflect the latter downwardly to the position shown in FIG. 3. Downward deflection of the diaphragm 54 moves the connector 116 downward thus moving the piston 86 and valve head 84 away from the valve seat 82 and opening the orifice 46 to permit the operating fluid to flow through the housing 16 along a path defined generally by the arrows 17. It is noted that the spring 87 is thus compressed to store energy used to close the valve when the control pressure is removed. As the piston 86 is thus moved further into the well 90, the incompressible lubricant in the lubricant chamber 96 forces the valve head 106 tighter against the valve seat 104 and concurrently forces the valve head 128 to move against the bias of the light spring 130 away from the valve seat 126. The lubricant is then forced to pass into and through the

passages

122 and 124 along the path defined generally by the arrows 125. Thus, when the main valve is opened to allow an operating fluid flowage to occur along a path through the housing, a charge of lubricant is automatically injected into the flow path, entrained in the operating fluid, and carried along therein to the starting motor to lubricate and clean the latter.

It is thus readily apparent that the main valve will remain open to permit the operating fluid to act upon the starting motor so long as the pressure in the control chamber 58 is elevated. When the engine 12 has been sufficiently cranked by the starting motor 4 and the former has begun to run under its own power, the fluid pressure in the line 38 will become elevated with the result that the pressure in the chamber 76 will rise and cause the diaphragm 74 to deflect into sealing engagement with the annular bead 80, as shown in FIG. 4. Fluid communication between the port 66 and the control chamber 58 is thus interrupted. The pressurized fluid in the control chamber 58 is then free to exhaust through a bleed port 81 thus lowering the pressure in the chamber 58. The force acting on the diaphragm 54 to deflect the latter downwardly is thus removed and the spring 87 is free to return to its original extension, thus moving the valve head 84 back into sealing engagement with the valve seat 82 and shutting off the flow of operating fluid to the starting motor. It is thus readily apparent that as soon as the engine starts, the starting motor will become automatically deactuated and will disengage from the engine, and furthermore, so long as the engine is running, it is impossible to actuate the starting motor with operating fluid.

As the spring 87 flexes to its original extension, the piston 86 is withdrawn from the well 90 to enlarge the volume of the lubricant chamber 96. The withdrawal of the piston 86 creates a vacuum in the chamber 96 which vacuum draws the valve head 126 tightly against the valve seat 126, and concurrently moves the valve head 106 against the bias of the light spring 108 and away from the valve seat 104. The vacuum thus draws lubricant from the conduit 26 past the valve head 106 and into the chamber 96, it being remembered that the lubricant tank 24 is at least exposed to atmospheric pressure. It is readily apparent that the lubricant chamber 96 will refill each time the main valve is closed and will thus be ready to inject a charge of lubricant into the flow path each time the main valve is subsequently opened. It will also be readily appreciated that the lubricant injector is self priming and the lubricant chamber can be initially filled by sequentially opening and closing the main valve several times.

While the precise fluid pressures needed to operate the device can be varied in accordance with individual requirements, it has been found that a control pressure of 120 psi. is satisfactory to cause the valve head spring 87 to deflect, the exact control pressure of course being determined by the spring rate of the springs 87 and 130. Since the area within the annular bead is smaller than the total area of the top surface of the diaphragm 74, it has been determined that an engine fluid pressure, for example engine oil pressure, somewhat in excess of 30 psi. can maintain the diaphragm 74 sealed against the annular bead 30 if the top surface area of the diaphragm 74 is about 1.5 in and the area within the annular head 80 is about 0.37 in.*.

One will readily appreciate that the valve assembly and engine starting system of this invention provides a plurality of fimctions within a minimum of space confined in a single housing which can be effectively sealed from the surrounding environment. The valve assembly of this invention is thus compact, easily assembled and serviced, and provides several safety features by preventing rearward flow of high temperature combustion gases into the operating fluid conduits, and further by preventing actuation of the starting motor when the engine is running.

What is claimed is:

1. A system for starting an engine, said system comprising:

a. a fluid actuated vane motor operative to engage the engine to crank the latter;

b. a source of pressurized operating fluid;

c. a housing having an inlet and an outlet, and providing a fluid flow path between said inlet and said outlet;

d. first conduit means interconnecting said source of operating fluid and said housing inlet;

e. second conduit means interconnecting said housing outlet and said vane motor;

f. valve means mounted in said housing between said inlet and said outlet, said valve means being operative to open and close said flow path to fluid flowage from said operating fluid source to said vane motor;

g. diaphragm means mounted in said housing for flexure therein said diaphragm means combining with a portion of said housing to provide a control chamber, and said diaphragm means being exposed to said outlet whereby said diaphragm means is operable to flex when fluid pressure in said outlet is relatively higher than fluid pressure in said control chamber;

h. a source of pressurized control fluid;

i. third conduit means interconnecting said control chamber and said source of pressurized control fluid whereby fluid pressure .in said control chamber can be varied to flex said diaphragm means; and

j. means interconnecting said diaphragm means and said valve means and operative to open said valve means in response to predetermined flexure of said diaphragm means induced by changes in fluid pressure in said control chamber, and further operative to close said valve means in response to flexure of said diaphragm means induced by said relatively higher fluid pressure in said outlet.

2. The system of claim 1, further comprising a source of lubricant; lubricant injector means mounted in said housing and operably connected to said valve means; conduit means interconnecting said lubricant source and said lubricant injector, said lubricant injector being operative to inject a charge of lubricant into said flow path within said housing when said valve means is opened, whereby said lubricant charge is entrained in a stream of operating fluid and transported therein to said vane motor.

3. The system of claim 16, further comprising means operative to ignite a charge of a combustible propellant to produce a volume of pressurized combustion gages to actuate said vane motor, said igniting means being connected to said second conduit means whereby said combustion gases are free to substantially raise the fluid pressure in said housing outlet to a point above the fluid pressure in said control chamber to flex said diaphragm means to close said valve means against flowage of said combustion gases from said housing outlet to said housing inlet.

4. The system of claim 1, further comprising a second diaphragm mounted in said housing and providing a condition chamber with a portion of said housing; conduit means interconnecting said condition chamber with a fluid pressure source in said engine, said fluid pressure source generating a higher fluid pressure when said engine is running than when said engine is not running whereby fluid pressure in said condition chamber is raised when said engine is running, thereby causing said second diaphragm to be flexedin response in said higher fluid pressure to seal said control chamber from said source of pressurized control fluid.

5. The system of claim 1, further comprising a source of a lubricant; a lubricant injector mounted in said housing and operably connected to said valve means, said injector being operative to inject a charge of lubricant into said flow path when said valve means is opened; and conduit means interconnecting said lubricant source to said lubricant injector.

Claims

1. A system for starting an engine, said system comprising: a. a fluid actuated vane motor operative to engage the engine to crank the latter; b. a source of pressurized operating fluid; c. a housing having an inlet and an outlet, and providing a fluid flow path between said inlet and said outlet; d. first conduit means interconnecting said source of operating fluid and said housing inlet; e. second conduit means interconnecting said housing outlet and said vane motor; f. valve means mounted in said housing between said inlet and said outlet, said valve means being operative to open and close said flow path to fluid flowage from said operating fluid source to said vane motor; g. diaphragm means mounted in said housing for flexure therein said diaphragm means combining with a portion of said housing to provide a control chamber, and said diaphragm means being exposed to said outlet whereby said diaphragm means is operable to flex when fluid pressure in said outlet is relatively higher than fluid pressure in said control chamber; h. a source of pressurized control fluid; i. third conduit means interconnecting said control chamber and said source of pressurized control fluid whereby fluid pressure in said control chamber can be varied to flex said diaphragm means; and j. means interconnecting said diaphragm means and said valve means and operative to open said valve means in response to predetermined flexure of said diaphragm means induced by changes in fluid pressure in said control chamber, and further operative to close said valve means in response to flexure of said diaphragm means induced by said relatively higher fluid pressure in said outlet.

4. The system of claim 1, further comprising a second diaphragm mounted in said housing and providing a condition chamber with a portion of said housing; conduit means interconnecting said condition chamber with a fluid pressure source in said engine, said fluid pressure source generating a higher fluid pressure when said engine is running than when said engine is not running whereby fluid pressure in said condition chamber is raised when said engine is running, thereby causing said second diaphragm to be flexed in response in said higher fluid pressure to seal said control chamber from said source of pressurized control fluid.