US 3917027 A
A system for pre-lubricating a quick starting, fluid cranked engine that is powered by a combusting fuel. The engine is started by a hydraulic or a pneumatic cranking motor; it usually runs an emergency (stand-by) electric generator which should come on line almost instantaneously in the event of the failure of a principal source of electrical supply. The prelubing must be rapid because of the quick cranking of such engines that is characteristic of fluid cranking, e.g. in the order of 2 seconds, as compared to electric cranking which conventionally takes several more seconds, it being important to pre-lube the engine bearing surfaces before such cranking in order to lengthen the life of the engine and thus reduce breakdowns. The pre-lubing system is energized by the same source of fluid energy that is used for the cranking, e.g. hydraulic accumulators or pressurized air vessels, enabling the pre-lubing system to be packaged with the fluid cranking system as a unit, thus conserving space and minimizing cost and maintenance. The pressure lines from the source of fluid energy to the cranking motor and to the pre-lubing system are in parallel so that when the power on the electric mains fails and causes opening of a valve from the source of fluid energy to the cranking motor and to the pre-lubing system the substantial inertial resistance of the engine and the lesser resistance of the pre-lubing system will defer operation of the cranking motor until the prior completion of a pre-lubing cycle, hence, ensuring a proper sequence of operation, to wit, first pre-lubing and only then cranking, both performed rapidly.
Description (OCR text may contain errors)
United States Patent [1 1 Hakanson et al.
[ SYSTEM FOR PRE-LUBRICATING AN OCCASIONALLY USED, FLUID CRANKED, QUICK STARTING, FUEL BURNING ENGINE  Inventors: Alton L. Hakanson; Wilbur C.
Schafer, both of c/o Mar-Oil Hydraulics Inc., 113-115 Monroe St., I-Ioboken, NJ. 07030  Filed: Dec. 14, 1973  Appl. No.: 424,651
Primary Examiner-Richard C. Pinkham Assistant Examiner-Marvin Siskind Attorney, Agent, or FirmKirschstein, Kirschstein,
Ottinger & Frank  ABSTRACT A system for pre-lubricating a quick starting, fluid Nov. 4, 1975 cranked engine that is powered by a combusting fuel. The engine is started by a hydraulic or a pneumatic cranking motor; it usually runs an emergency (standby) electric generato'r'which should come on line almost instantaneously in the event of the failure of a principal source of electrical supply. The prelubing must be rapid because of the quick cranking of such engines that is characteristic of fluid cranking, e.g. in the order of 2 seconds, as compared to electric cranking which conventionally takes several more seconds, it being important to pre-lube the engine bearing surfaces before such cranking in order to lengthen the life of the engine and thus reduce breakdowns. The pre-lubing system is energized by the same source of fluid energy that is used for the cranking, e.g. hydraulic accumulators or pressurized air vessels, enabling the pre-lubing system to be packaged with the fluid cranking system as a unit, thus conserving space and minimizing cost and maintenance. The pressure lines from the source of fluid energy to the cranking motor and to the pre-lubing system are in parallel so that when the power on the electric mains fails and causes opening of a valve from the source of fluid energy to the cranking motor and to the pre-lubing system the substantial inertial resistance of the engine and the lesser resistance of the pre-lubing system will defer operation of the cranking motor until the prior completion of a pre-lubing cycle, hence, ensuring a proper sequence of operation, to wit, first pre-lubing and only then cranking, both performed rapidly.
16 Claims-.93 Drawing Figures US. Patent Nov. 4, 1975 FIG. 3
7'0 EZECTR/C M/l/IV SYSTEM FOR PRE-LUBRICATING AN OCCASIONALLY USED, FLUID CRANKED, QUICK STARTING, FUEL BURNING ENGINE BACKGROUND OF THE INVENTION 1. Field of the Invention Pre-lubricating systems.
2. Description of the Prior Art It has been proposed heretofore to lubricate engines, and particularly the main bearing surfaces of engines, before starting the engines, typically where the engines in question were not run on a regular basis such, for example, as stand-by engines which might not be energized for days or months. These engines conventionally were internal combustion engines and usually were cranked electrically. When engines of this nature were started only infrequently and were cranked by electric power, the cranking and starting were comparatively slow; many seconds were consumed in cranking the engines before they would catch. The pre-lubing systems proposed for such engines were intended to operate before the engine started. However, due to the inherently slow starting of the engines, slowness of prelubing and the possible overlap between the pre-lubing cycle and the cranking cycle presented no serious difficulty. It was most unlikely that the engine would start to turn over at a normal idling speed before the pre-lubing was completed. Therefore, the pre-lubing could be done in what might be termed a comparatively leisurely manner and it was customary to employ electrically powered pre-lubing arrangements.
However, the foregoing systems essentially are useless where the stand-by engine is cranked by a fluid system, eg a fluid motor. Such motors essentially crank and start fluid fuel engines with extreme rapidity, a typical cranking cycle being in the order to 2 seconds; that is to say, by the time four seconds have elapsed the engine will be turning at an appreciable speed and may have caught. The power required for rapid starting is quite substantial, being available from stored fluid energy sources. This quick starting is absolutely necessary in certain circumstances such, for instance, as stand-by engines for electric mains where it is of the essence that a breakdown of a power source not be permitted to persist for more than a few seconds, hence, the standby engine must be on line almost immediately following the failure of the main source of energy for powering an electric main. Thus, for fluid cranked engines, which is to say, hydraulically or pneumatically cranked engines, it is important that pre-lubing be performed before the engine has had a chance to start or else, particularly if there is any overlap of the pre-lubing and cranking cycles, the engine may start to run on dry bearings and be substantially damaged.
Up to the present time no pre-lubing system has been proposed which can accomplish this desirable end nor has a pre-lubing system been proposed which can use a single source of power, specifically stored fluid energy, to operate both the pre-lubing system and the cranking motor and at the same time to ensure that pre-lubing is completed before cranking is initiated.
SUMMARY OF THE INVENTION 1. Purposes of the Invention It is an object of the invention to provide a prelubricating system which is specially designed to be used with a fluid cranked engine of the quick starting 2 type and which system is so designed that it will lubricate the engine rapidly before the same is cranked.
It is another object of the invention to provide a prelubricating system of the character described which can be combined with a fluid cranked engine to form therewith a package in which both the cranking and the pre-lubricating is powered by a source of fluid under pressure such, for example, as a hydraulic accumulator or a vessel containing pressurized air.
It is another object of the invention to provide. a prelubricating system of the character described in which the pressurized fluid inputs to the cranking motor and to the pre-lubricating system are derived from a common source so that without incorporating any special equipment the cranking motor will not be started until the pre-lubricating system has completed its lubricating cycle due to the fact that the cranking motor, which'is in mechanical engagement with the engine, offers a far higher resistance to in-flow of the pressurized fluid than does the pre-lubricating system.
It is another object of the invention to provide a prelubricating system of the character described in which an arrangement is included to dump hydraulic fluid, when such is employed to start the pre-lubricating systern, back to a storage tank after the engine has caught and is operating a pressurized oil lubricating system of its own.
It is another object of the invention to provide a prelubricating system of the character described in which a reservoir of pre-lubricating oil is stored after the engine has started ready to be used for a fresh prelubricating cycle the next time the engine is to be started, even if this may be days, weeks or months in the future.
It is another object of the invention to provide a prelubricating system of the character described constituting relatively few and simple parts, which can be made i economically, serviced readily, and is comparatively inexpensive.
Other objects of the invention in part will be obvious and in part will be pointed out hereinafter.
2. Brief Description of the lnvention The pre-lubricating system of the present invention is designed to be used in connection with a quick starting fluid cranked engine that derives its running energy from combustion of fuel. Typical such engines are diesel engines, natural gas engines and gas turbine engines. The engine, as just stated, is of the quick starting type because a principal purpose of such an engine is to serve as a stand-by source of mechanical power to drive an electrical generator in the event that the normal source of power fails and the electrical mains are dead. In most instances where engines of the foregoing type are employed there is no available alternate power grid.
7 Such a stand-by engine might be used in a hospital to supply emergency power if the available power transmission network is blacked out. Another place where such engines are used is in remote unattended stations such, for instance, as communication relay stations or weather stations which are remote from civilization and which are intended to operate without human assistance. Still another place where such engines are found, and probably one of the major fields of use of such engines, is aboard ships.
In all of these cases, if there is a failure of electric power, serious and sometimes disastrous consequences ensue. Therefore, it is the practice to provide for this contingency a stand-by engine and generator. It is quite apparent that if the stand-by engine does not come into operation almost immediately upon the failure of the main electric power, considerable damage could follow. In a hospital the failure could take place in the middle of an operation. In an automatic station the failure could take place at a critical moment when a report is needed from this station. In a ship the failure could take place in a storm or while a surgical operation is being performed aboard the ship, or, if the ship is steered by use of synchronous motors, at an important moment when a disaster only could be averted if the rudder is operable.
It thus will be appreciated that, regardless of all other factors, it is to the essence that the stand-by motor be capable of running at full power within a matter of a very few seconds, e.g., 2 seconds, after the demand for it arises. This is true even if the stand-by engine should be severely damaged because of a fast start. All things considered, the possibility that the stand-by motor can only be used once must be weighed against the importance of the immediate start of the engine to avoid all manners of contingencies. Naturally, it is not economical to use a stand-by engine only a single time nor, indeed, would anyone expect that this would happen. The only thing that ordinarily can damage a quick starting engine is to have it start up on dry bearings, and even this can be countenanced if cost is disregarded. Yet, cost necessarily should constitute one of the parameters governing the type and auxiliaries of a standby engine. Therefore, if it is possible, it woulb be better to be able to pre-lubricate the engine before it starts. However, the pre-lubrication must be extremely rapid due to the foregoing factors which necessitate a quick supply of driving power to the electrical generator, be it a stand-by or a principal generator.
It will be appreciated, for the reasons mentioned previously, that none of the factors just discussed affects electrically cranked engines because where these engines are used on a stand-by basis no one expects them to start up almost instantaneously. They become cold on standing and deposits are formed in the engine cylinders and in the valves, all of which contribute to slow starting. Therefore, rapid pre-lubrication is not a major factor and, indeed, electrically cranked engines turn over comparatively slowly at starting so that the burning out of bearings is not likely to ensue.
Of course, the converse is true of a rapidly cranked engine because in these engines the crankshaft turns over quickly to make certain that the starting is fast, and it is possible to turn the crankshaft over so quickly that damage to dry bearings cannot be prevented. Of course, a source of lubricating fluid under high pressure could be stored ready to perform the pre-lubrication before the rapid cranking. But this involves a rather expensive and large apparatus and also involves synchronizing the pre-lubricating and cranking so that the pre-lubricating is completed before cranking starts.
The present invention avoids these defects by supplying a pre-lubricating system that coordinates with the fluid cranking motor employed for starting the engine. Specifically, the present invention utilized for prelubricating the same source of fluid energy, to wit, a hydraulic accumulator or a pressurized gas, e.g., a compressed air vessel, that is employed to energize the cranking motor. This source of energy is led to the prelubricating system and can be applied to one end of a cylinder with a floating piston therein. The application of the pressurized fluid to this end of the cylinder occurs concurrently with the application of the pressurized fluid to the cranking motor. However, although the cranking motor almost immediately engages the engine to be started, the cranking motor stalls momentarily due to the high inertia of the engine. If there were no pro-lubricating system according to the present invention employed in conjunction with the aforesaid cranking motor, the stalling of the motor only would be evanescent because the motor is large enough and the fluid is sufficiently pressurized and is supplied in sufficient volume to overcome the inertia of the engine. Indeed, that is the very purpose of a pressurized fluid cranking motor, to wit, to bring the engine up to high speed within a matter of a very few seconds so that there is, in effect, no appreciable down time in the electrical mains. But, in the present case, i.e., in accordance with the present invention, the cranking motor does noticeably stall, which is to say, it does not start the engine immediately because there is a path oflower resistance which the pressurized liquid may follow, this being against the floating piston in the aforesaid cylinder.
In this cylinder on the opposite side of the piston is a supply of pre-lubricating liquid, e.g., oil. The piston is supplied with a biasing means, preferably internally of the cylinder, which urges the piston toward the end of the cylinder to which the source of fluid energy is applied, so that when no fluid energy is applied to the aforesaid cylinder and piston, the piston provides a large chamber in which lubricating liquid is stored while the stand-by engine is not in operation. A valve is located in the output from the source of fluid energy, the valve being normally closed and remaining closed so long as there is electric energy on the mains. The valve is responsive to such energy and will open when the energy fails, thereby to lead pressurized fluid to the cranking motor and to the pre-lubricating system immediately following loss of electrical power.
As stated just previously, the application of pressurized fluid to the cranking motor is ineffective to start the cranking motor so long as a path of lesser resistance is available, to wit, the path to the pre-lubricating system. Thereby the pressurized fluid is applied to the face of the piston remote from the stored pre-lubricating liquid. This forces the piston along the cylinder and ejects pre-lubricating liquid therefrom. The pre-lubricating liquid is led to the lubricating system of the engine, including paths to the main bearings; accordingly, the engine now is ready to start. When the piston comes to a stop and presents a now almost infinitely high path of resistance to the flow or pressurized fluid, said pressurized fluid now seeks to function in the path supplying energy to the cranking motor and thereby immediately starts to turn the motor over, in turn spinning the engine and causing the same to start expeditiously.
After the engine has started, the lubricating fluid therein is under pressure. This pressure is used to open a normally closed dump valve that leads from the driving side of the piston (the side to which the source of fluid energy is connected upon failure of power in the mains) to a reservoir for the fluid used in the source of fluid energy. As soon as the stand-by engine is in operation, electric power will be present on the mains causing the valve in the output from the source of fluid energy to close. Immediately thereafter the pressure of the oil in the lubricating system of the now-running engine will open the dump valve allowing the fluid present on the driving side of the piston to be forced by the piston biasing means into the reservoir. As the piston retracts it pulls in lubricating liquid, e.g., from the sump of the engine, to store the same in the cylinder awaiting the next time that a pre-lubricating cycle is to be performed.
The invention consists in the features of construe tion, combination of elements and arrangement of parts which will be exemplified in the system hereinafter described and of which the scope of application will be indicated in the appended claims.
4 BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings in which are shown various possible embodiments of the invention:
FIG. 1 is a partly sectional, partly schematic view of a pre-lubricating system embodying the present invention, the same being illustrated in conjunction with a hydraulically energized cranking motor and an engine;
FIG. 2 is an illustration of a portion of a pre-lubricating system constituting a modification of the system shown in FIG. 1; and
FIG. 3 is an illustration of a portion ofa pre-lubricating system constituting another modification of the system shown in FIG. 1.
PREFERRED EMBODIMENTS OF THE INVENTION Referring now in detail to the drawings, the reference numeral denotes a stand-by engine arranged to drive an electric generator 12 which normally is arranged to be driven by another engine 14. The engine 14 is a heavy duty engine which is designed to operate for long periods of time without breakdown and is the principal source of power for driving the generator 12. In many installations embodying the present invention there are two generators 12 each connected to a common electric power main, one generator being arranged to be driven by the principal engine 14 and the other (standby) generator being arranged to be driven bythe standby engine 10. Thereby if a normally used generator or a normally used engine should fail, the stand-by engine and stand-by generator would come into play. The number of generators employed will depend upon the particular requirements of the installation and the economics thereof.
The stand-by engine 10 conventionally will be a diesel engine or a natural gas engine or a gas turbine engine, all of these being engines which are powered by a combusted fuel. The stand-by engine 10 customarily will not have been used for a considerable period of time before it is called into service suddenly and, therefore, all of the oil therein will have drained to the crankcase, i.e., sump 16, so that the bearings, and notably the main bearings, essentially are dry. The amount of residual oil thereon is negligible; it is completely insufficient to lubricate the bearings when the crank shaft is turning rapidly regardless of whether a load is present or absent. Moreover, the oil is not under pressure and, therefore, will not provide a film of sufficient thickness to afford suitable lubrication and prevent burning of the bearings.
As observed previously, it is today almost invariably necessary that the stand-by engine 10 be quick starting. To enable an engine such as an engine for driving generator of any appreciable size to start rapidly the engine must be spun quickly, that is to say, turned over as by cranking at a speed far in excess of that which is attainable by conventional electric cranking motors. Such high speed cranking is well known, as are the means for accomplishing the same. High speed cranking customarily is performed by a motor that is energized by a source of fluid energy. Best results are obtained where the source of fluid energy is liquid such, for instance, as a hydraulic fluid. This kind of cranking motor is notoriously reliable for a very fast start of an engine. It overcomes the high inertia of the engine quickly and quickly brings the engine up to a speed sufficient for starting and sufficient for compression, in the event that it is a compression engine, rapidly.
In the aforesaid fluid cranking system cranking of the engine is effected by a fluid driven cranking motor 18 having a pinion (not shown) designed to engage a gear (not shown) on the shaft of the engine 10. It is customary for the pinion normally to be out of engagement with the gear and to be urged into engagement therewith when a source of fluid under pressure is supplied to the high pressure side of the cranking motor 18. Such source of high pressure fluid is provided in the system illustrated by one or a few hydraulic accumulators 20, two being shown, connected in parallel. If desired, instead of hydraulic accumulators, compressed air flasks, e.g., vessels, can be employed which are connected to the cranking motors.
In a customary such cranking installation suitable valving is interposed between the source of fluid under pressure and the cranking motor, this valving normally disconnecting the source of fluid under pressure from the cranking motor and enabling a connection to be effected under the control of an operator or automatically, as may be desired, in the event of the failure of power on the electric mains.
Turning now to the pre-lubricating system of the present invention, the same includes a linear round cylinder 22 of uniform internal diameter in which a piston 24 rides. The piston may be free-floating as illustrated, i.e., not connected to a shaft although, if desired to have the piston control some other mechanism, it may be provided with a shaft extending through a seal in an opening in an end of the cylinder. Inasmuch as no such mechanism presently. is contemplated in connection with the instant invention, no shaft is illustrated. The piston usually will be provided with sealing rings 26 to prevent leakage across the piston between the chambers in to which the cylinder is divided by the piston.
The piston has a driving face 28 which defines one end of a driving chamber 30, the other end of which is defined by a transverse wall 32 through which hydraulic fluid under high pressure is adapted to be fed from a conduit 34. The other and driven face 36 of the piston 24 defines one end'ofa chamber 38 which is the prelubricating chamber or storage chamber for prelubricating liquid. The far end of the storage chamber constitutes a transverse wall 40 through which a connection from the chamber is effected to a pre-lubricating conduit 42. Internally of the chamber 38 an annular stop ring 44 is formed to define the minimum size of thestorage chamber as the piston moves toward the wall 40 and the conduit 42.
Furthermore, biasing means in the form of a helical compression spring 46 is located in the cylinder 22 within the chamber 38. Alternatively, such spring could be located externally of the cylinder and function in conjunction with a shaft carried by the piston.
In idle condition of the pre-lubricating system said spring urges the piston 24 deeply into the driving chamber 30, e.g., against a stop (not shown) or against the transverse wall 32, or, if desired, simply to the limit of travel of the spring 46 to relaxed position.
The conduit 34 is connected through a valve 48 and a second conduit 50 to a manifold 52 attached to the outlets of the hydraulic accumulators 20. The valve 48 is normally closed. It includes an actuator which, when activated, will open said valve. Any kind of actuator may be used, e.g., a fluid operated actuator or an electrically operated actuator. Thus, the actuator may be a solenoid with a biasing means to urge the valve to open condition. This bias is overcome when the solenoid is energized, the solenoid being connected to the electric mains, so that as long as power is present in the mains the solenoid will hold the valve 48 closed, but the moment that there is a power failure on the mains, the valve 48 will open.
A further conduit 54 is connected to the conduit 34 and runs from said conduit 34 to the pressure inlet of the cranking motor 18. If desired, an off/on valve 56 may be interposed in the conduit 54 for testing or emergency use.
A conduit 58 runs from the pre-lubricating conduit 42 to the pressure side of an engine oil pressure pump 60 or to any point in the pressure side of the engine lubricating system. This conduit has a check valve 62 interposed therein which permits flow of lubricating oil from the conduit 42 only toward the engine lubricating system.
Considering the operating of the pre-lubricating system of the present invention only insofar as the prelubrication cycle is concerned, that is to say, without consideration of the return cycle of the pre-lubricating system which subsequently will be described slong with the parts of the pre-lubricating system associated therewith, let it be assumed that the stand-by engine is idle but that either the generator 12 or some other generator which is connected to the electric mains is operating so that the electricl mains are supplied with their normal power. Previously to this time, the biasing spring 46 will have urged the piston 24 to a position remote from the transverse wall 40 so that the prelubricating chamber 38, i.g., storage chamber, will be of a sizeable volume and, through a mode of operation which will be discussed hereinafter with respect to the return cycle of the pre-lubricating system, is full of prelubricating oil. The check valve 62 is closed due to an internal biasing means, as is conventional in a check valve. The valve 48 is closed since the electric mains are powered; hence, there is no fluid connection from the accumulators to the cylinder 22. The cylinder actually is at the time, due to other connections which will be described, isolated from the source of fluid energy, the engine lubricating system, and from a storage reservoir for hydraulic fluid hereinafter to be described. The pre-lubricating oil in the storage chamber is awaiting its instructions, so to speak, for effective pre-lubricating operation.
If now the supply of power in the electric mains fails and momentarily the electric mains are devoid of energy or else the energy is so low as to be insufficient to supply normal demands and, therefore, insufficient to maintain the valve 48 closed, the valve 48 opens so as to contact the source of fluid energy under pressure through the manifold 52, the conduit 50, the valve 48 and the conduit 34 to the driving chamber side of the cylinder 22. In turn, this applies high pressure fluid to the driving face 28 of the piston 24 urging the piston with considerable force toward the transverse wall 40.
Concurrently, the source of fluid under pressure from the accumulators 20 will apply pressure through the conduit 54 to the cranking motor 18. Initially, this is ineffective to crank the engine 10 because even though there may be some slight motion of a part of the cranking motor, e.g., motion of the cranking piston toward the starting gear in the engine, the large inertial mass of the moving parts of the engine present a far greater resistance to the source of fluid under pressure than does the biasing spring 46. Hence, the piston 24 will, before cranking can take effect, travel toward the stop 44 and, in so doing, sweep in front of it the lubricating liquid (oil) in the chamber 38. This liquid will exit through the conduit 42 to flow through the conduit 58 and the check valve 62 to the high pressure side of the engine lubricating system entering, for example, through the outlet from the engine oil pressure pump to the engine lubricating system. The chamber 38 is of sufficient size to supply the necessary amount of lubricating liquid for pre-lubrication. The motion of the piston, as aforesaid, from its idle position to the stops is quite rapid. A typical time is from 2 to 4 seconds.
The engine 10 may have a turbo-charger T associated therewith to increase the horsepower of the engine output. A turbo-charger turns at a very high speed so that its bearings are very susceptible to scoring if not prelubricated. Accordingly, if a turbo-charger is employed, a conduit 63 connects the conduit 58 on the engine side of the check valve 62 to the lubricating system of the turbo-charger. Thereby the turbo-charger will be pre-lubricated concurrently with the engine prior to starting of the engine and the turbo-charger.
The forgoing terminates the pre-lubricating cycle but not the return cycle for the pre-lubricating system. When the piston 24 reaches the end of its pre-lubricating stroke it presents a very high resistance to the source of fluid pressure. The only fluid then possible is along the sides of the piston where it is effectively blocked by the piston rings. Therefore, the source of high pressure fluid now turns to the cranking motor 18 whereby, the instant pre-lubricating ceases, cranking of the engine starts. This, too, proceeds very rapidly because of the use of high pressure fluid. Accordingly, the engine is brought up to speed rapidly and catches, to start the generator 12 turning so as to re-establish electric power on the mains.
Turning now to the return cycle of the pre-lubricating system, the pre-lubricating cycle itself having been described as well as the mechanisms by which the same is performed, when the stand-by engine 10 is running and the generator 12 thereby supplies full electric power to the electric mains the presence of this power is immediately detected by energization of the power responsive means which causes the valve 48 to be reclosed, thus cutting off the connection between the conduit 52 and, hence, the source of fluid energy 20 and the conduit 34 that runs to the cylinder 22 and the pump 60. Thus, if the valve 48 is controlled by a solenoid to close the same and a spring is employed to open it when the solenoid is de-energized so that the valve is a fail-safe valve, energization of the electric mains will cause such solenoid to be actuated and the valve to be closed against the bias of the valve opening spring. When the valve 48 closes, the cylinder 22 is isolated as heretofore mentioned. Nevertheless, the fluid, e.g., hydraulic fluid, in the driving chamber 30 is under pressure, albeit a smaller pressure tham that supplied from the source of fluid energy 20, this mild pressure being supplied by action of the spring 46 on the driven face 36 of the piston 24. Hence, the fluid in the conduit 54 is under such mild pressure. The conduit 54 is connected to a conduit 64 that runs to a reservoir 66, the reservoir in the system being described being a reservoir for hydraulic liquid such, for instance, as hydraulic oil. The conduit 64 includes means to effectively block flow of hydraulic fluid from the conduit 64 to the reservoir. The blocking can either be positive as shown in FIG. 1, or of a leak or bleed type as will be described with respect to FIG. 2. In the form of the invention now under consideration a dump valve 68 is interposed in the conduit 64 between the conduit 54 and the reservoir 66. This valve normally is closed as, for example, being urged to such closed position by a spring (not shown). An operator 70 such, for instance, as a pistonand-cylinder is arranged to mechanically open the valve 68. When the operator is idle the valve is closed. When the operator is energized it opens the valve against the spring force biasing it to closed position. The operator is arranged to become effective when the engine 10 starts. Any suitable arrangement can be employed for this purpose. For example, the operator, instead of being a piston-and-cylinder, could be a solenoid operating off an auxiliary generator connected to the stand-by engine 10. More conveniently, the operator 70 is a hydraulic operator such, for instance, as the piston-and-cylinder just mentioned and it is energized by a liquid which is placed under pressure when the engine starts. In the illustrated example, to accomplish this purpose the operator is connected by a conduit 72 to the engine lubricating system. For example, it may be connected to the pressure side of the engine oil pressure pump 60. A flow restriction valve 74 is interposed in the conduit 72. This valve acts as a leak valve permit ting a slow flow or fluid through the conduit 72 to the operator 70. Thereby shortly after the engine has started up enough oil passes through the valve 74 to energize the operator 70 which, in turn, opens the dump valve 68, thus providing a free path from the driving chamber 30 to the reservoir 66. This path permits return of the hydraulic fluid to the reservoir from which it subsequently can be pumped by a pumping means (not shown) back to the hydraulic accumulators 20, as the need may arise. It will be observed that the valve 56 is a manually controlled valve which in the automatic operation of the pre-Iubricating system is left permanently open. It may be desirable to close the valve upon occasion to test the operation of the pre-lubricating system, but this is merely an optional feature of said system.
When the piston 24 returns to its idle or stand-by position adjacent the transverse wall 32 of the cylinder 22 it also draws into the pre-lubricating storage chamber lubricating oil from any available source. A convenient source is the engine sump 16. Hence, for this purpose a conduit 76 runs from the conduit 42 to the sump, the conduit 76 having interposed therein in any desired order a filter 78 to ensure removal from the prelubricating oil of any deposits of foreign material that may have accumulated in the sump, and a check valve 80 which permits flow of oil to the pre-Iubricating chamber 38 from the engine sump, but not in a reverse direction, the flow from a pre-lubricating chamber to the engine being only via the conduit 58, as described above.
It will be observed that the presence of the flow restriction valve 74 prevents flow of a sufficient volume 10 of liquid to open the operator during the short prelubricating cycle, so that there is'no danger ofinadvertent opening of the dump valve 68 at this time when there is high pressure present in the conduits 34 and 54 as well as in the conduit 64 up to the dump valve.
The return cycle of the aforesaid pre-lubricating system can be simplified in accordance with the modification illustrated in FIG. 2. The portion of the system which has been altered is between the conduit 34 and the reservoir 66. Specifically, there have been omitted the dump valve 68, its operator 70, the conduit 72, and the restriction valve 74. However, it still is necessary to provide a suitable arrangement for preventing any more than a negligible flow of fluid from the source of fluid energy 20 to the storage tank 66 during the prelubrication cycle. Therefore, instead of the aforesaid elements that have been omitted, there is inserted in the conduit 64 a flow restriction valve 82 which is so constructed, or, if hand-adjusted, so adjusted, that the bleed or leak flow of high pressure fluid from the source of energy 20 to the storage tank during the prelubricating cycle is so small as to be insignificant during the short time that the valve 48 is open. However, when the valve 48 is closed and the fluid in the chamber 30 is under the mild pressure of the spring 46, the fluid present in the chamber 30 will gradually be returned to the storage tank 66 as the piston 24 moves back to idle position. This return flow can be done over a prolonged period of time because in ordinary course there is no reason to shift the piston 24 quickly from adjacent the wall 40 to adjacent the wall 32. Even if a few minutes is consumed for this shift, the system will function satisfactorily. It is only necessary that eventually the piston 24 be restored to its idle position and consequent the reupon the pre-lubricating chamber 38 be filled with lubricating oil.
In an alternate form of the invention the engine lubricating oil for the pre-lubricating cycle is supplied from a source other than the engine sump 16 which is the source shown in FIG. 1. Such alternate form is illustrated in FIG. 3 where the replenishing engine oil for the chamber 38 is drawn through a conduit 84 from the pressure side of the engine Lubricating system or any conduit connected to it. Said conduit 84 bypasses the check valve 62 and includes in it an adjustable flow restriction valve 86, whereby on the return cycle replenishing oil for the chamber 38 is drawn from the pressure side of the engine oil lubricating system. When this different source of replenishment for oil is employed, the conduit 76, the filter 78 and the check valve 80 are omitted.
It thus will be seen that there are provided systems which acheive the various objects of the invention and which are well adapted to meet the conditions of practical use.
As various possible embodiments might be made of the above invention and as various changes might be made in the embodiments above set forth, it is to be understood that all matter herein described or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.
Having thus described the invention there is claimed as new and desired to be secured by Letters Patent:
1. In combination with an occasionally used, quick starting, fuel burning engine for driving an electric generator that powers an electric main, which engine has a lubricating system, and which has associated therewith a fluid energized rapid cranking system that includes A. a fluid energizeable cranking motor,
8. a source of fluid under pressure,
C. a first conduit connecting the source of fluid under pressure to the cranking motor,
D. a normally closed valve in said conduit upstream of the cranking motor, and
E. means for opening the valve when the electric main is de-energized,
a pre-lubricating system that comprises:
I. a chamber storing lubricating liquid,
11. a second conduit connecting said chamber to the engine lubricating system,
Ill. a check valve in the second conduit that permits flow of lubricating liquid only toward the engine lubricating system,
IV. means for pressurizing the lubricating liquid in the chamber to force the liquid through the second conduit into the engine lubricating system, and
V. a third conduit connecting the first conduit downstream of the valve to the pressurizing means,
Vi. whereby when the valve is opened and fluid under pressure concurrently is applied to the cranking motor and to the pressurizing means, operation of the cranking motor will be deferred due to the inertia of the engine until the pressurizing means has completed a pre-lubricating cycle.
2. A pre-lubricating system as set forth in claim 1 which further comprises a fourth conduit connecting the second conduit to a region of pressure below the pressure created by the pressurizing means, and means effectively blocking flow of fluid through the fourth conduit.
3. A pre-lubricating system as set forth in claim 2 wherein the blocking means includes a bleed device.
4. A pre-lubricating system as set forth in claim 2 wherein the blocking means includes a normally closed valve and means to open the valve when the engine is running.
5. A pre-lubricating system as set forth in claim 4 wherein the means to open the valve includes a hydraulic operator and a fifth conduit connecting the operator to the engine lubricating system.
6. A pre-lubricating system as set forth in claim 5 wherein fifth conduit has interposed therein a flow restriction valve.
7. A pre-lubricating system as set forth in claim 6 wherein the flow restriction valve is a manually regulatable valve.
8. A pre-lubricating system as set forth in claim 2 wherein a storage reservoir is included to constitute the means providing a region of pressure below the pressure created by the pressurizing means.
9. A pre-lubricating system as set forth in claim 1 which further comprises a sixth conduit leading from a source of lubricating liquid to the storage chamber and means to force such lubricating liquid into the chamber after the valve has closed and the engine is running.
10. A pre-lubricating system as set forth in claim 9 wherein there are two chambers, one chamber constituting the storage chamber and the other chamber constituting the pressurizing means, and wherein means is included to transfer pressure from the pressurizing chamber to the storage chamber when the valve is open.
11. A pre-lubricating system as set forth in claim 9 including a cylinder having a floating piston therein which subdivides the piston into the storage chamber and into the other chamber. 7
12. A pre-lubricating system as set forth in claim 1 wherein means is included to bias the piston toward the pressurizing chamber.
13. A pre-lubricating system as set forth in claim 1 wherein a turbo-charger is associated with the engine, the turbo-charger having a lubricating system, and wherein a conduit is provided connecting the second conduit to the turbo-charger lubricating system.
14. A pre-lubricating system as set forth in claim 1 wherein a further conduit is provided connecting the second conduit to the engine lubricating system, said further conduit including means preventing appreciable flow from the engine lubricating system to the second conduit.
15. A pre-lubricating system as set forth in claim 14 wherein the further conduit is connected to the engine sump and wherein the means preventing substantial flow is a check valve.
16. A pre-lubricating system as set forth in claim 14 wherein the further conduit is connected to the high pressure side of the engine lubricating system, and wherein the means preventing substantial flow is a flow restriction valve.