US2446691A - Engine starting apparatus - Google Patents

Description

Aug. 10, 1948. G. CLYDE EI'AL ENGINE STARTING APPARATUS 3 sheets-sheet 1 Filed April 6, 1944 rge Clyde,

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Filed April 6 1944 Q?) i 5. CLYDE HAL KL 44 ENGINE STARTING LPPARATUS I I5 Sizaests-Shast 2 Aug, ll! 3948. G. CLYDE EIAL 2,446,691

ENGINE STARTING APPARATUS Filed April 6, 1944 3 Sheets-Sheet 3 Patented Aug. 10, 1948 UNITED STATES PATENT OFFICE Columbus, Ohi

Application April 6, 1944, Serial No. 529,834

4 Claims. 1

This invention relates to improvements in engine starting systems, and, while not so limited, is directed particularly to an improved starting system for the internal combustion engines of airplanes.

In the manufacture of light airplanes, such as those employed in civilian aviation, theproblem of providing a satisfactory and reliable starting system has not been completely solved. In many instances, the engines of light airplanes are started by manually rotating the propeller, which generally is a dangerous practice. In some cases. use is made of the conventional electric starter, involving a starting motor, a gear actuated by the motor and engageable with the gear teeth of the engine flywheel and the conventional storage batteries for the energizing of the motor. In such a system, it is, of course, necessary to maintain the batteries in a charged state to efiect proper energization of the electric starting motor, and both the motor and the batteries add considerable weight to the plane, which is useless and undesirable when the plane is in flight. As the engines increase in horse power, it is necessary to use larger starting motors and heavier storage batteries to take care of the increased torque. Often in larger engines, the electric starting motor operates an inertia member which, when mtating at a desired rate of speed, is engaged with the engine to efiect its initial operation for startting purposes. In cold w-.tther particularly, the electric starting systems are slow to turn over, and their starting elements do not attain a sufficiently accelerated rotating speed to provide prompt starting of an associated engine. Various other starting systems have been used, such as the manually rotated inertia type, or systems involving gas expansion produced by the us of explosives. All these systems have their disadvantages and objectionable features, and at present the electrical system, above indicated, is the one most widely used.

It is, therefore, an object of the present invention to provide a reliable, lightweight and low cost starter for airplane engines, particularly civilian craft, wherein a compressible fluid is placed under high pressure in a confined chamber, exerting its force on a movable piston communicating with said chamber, the piston, in turn, applying pressure to a liquid, whereby through the medium of a manually controlled valve, such liquid under the pressure of the expansible fluid, is utilized to effect the rotation of a liquid-pressure motor, the driving shaft of the latter being employed, through a manually con- 2 trolled operation, to operate a pinion adapted for movement into and out of engagement with gear teeth provided on the flywheel of the associated engine.

In accordance with the present invention, the gas pressures necessary in obtaining its operation may be developed by the use of a small manually operated pump, or may be produced by the employment of an engine-driven pump. Also, the manual control employed in opening the valve admitting liquid under pressure into the starting motor, is utilized for effecting engagement of the shaft pinion of the starting motor with the gear teeth of the engine flywheel, whereby in a single operation of said control, the engagement of the pinion with the gear teeth is first effected so that upon continued movement of the control, the motor valve is opened, whereby operation of the motor applies power directly to the engine shaft for starting purposes.

It is another object of the invention to provide a starting system which may be readily applied to existing engines without alteration in their mechanical features of design.

It is a further object of the invention to provide a self-contained starting system which is readily available for use at all times, and wherein auxiliary devices, such as storage batteries or other equipment subject to failure, are eliminated.

For a further understanding of the invention, reference is to be had to the following description and the accompanying drawings, wherein:

Fig. 1 is a view in side elevation, and partly in vertical section, disclosing our improved engine starting mechanism;

Fig. 2 is a vertical sectional view taken through the accumulator unit of thestarting mechanism;

Fig. 3 is a front elevational view of the liquidpressure motor;

Fig. 4 is a detail sectional view disclosing th shiftable pinion on the spline shaft of the liquidpressure motor;

Fig, 5 is a detail sectional view disclosing the valved liquid inlet of said motor;

Fig. 6 is an elevational view, partly in vertical section, of a modified arrangement of the starting apparatus;

Fig. 7 is a similar view of another modified form.

Fig. 8 is a detail vertical sectional view taken through the fluid motor controls on the line 8-8 of Fig. 3.

Referring to the drawings, the numeral 10 designates the fuselage of an aiplane, the numeral ll designates the engine, and the numeral l3 the 3 propeller which is driven by said engine. The engine may be of any standard type. and in this instance, the engine depicted in Fig. 1 has its cylinder arranged in horizontal order.

Leading from the crank case or oil sump of the engine is a pipe line l4, by means of which a portion of the lubricating oil of the engine 15 transferred gravitationally to an accumulator l5. This accumulator comprises a base casting IS, the latter being formed at one end with a vertical bore ll. The bottom of this bore is threaded for the reception of a fitting I8, which receives the lower end of the pipe line l4. The fitting |8 is formed with a valve seat in which is provided an orifice l9, and normally closing the latter is a spring-pressed ball valve 20. The upper end of the bore terminates in an orifice 2|, which is normally closed by means of a spring-pressed ball valve 22, the latter being accessible by means of an opening 23provided in the upper portion of the base I8 and which opening is normally closed by means of a removable plug 24.

Formed horizontally in the base l8 and communicating at one end with the vertical bore I1 is a piston chamber 25. Mounted for sliding movement within this chamber is a reciprocable piston 25. The outer end of this piston is slidably received in a packing gland 21 and, exteriorly of the casting I5, is pivotally connected, as at 28, to the lower end of a manually operated pump lever 29, the latter being pivotally mounted as at on a supporting bracket projecting from the cowl panel 3|. By oscillating the lever29, reciprocating motion is imparted to the piston 25. On its outward stroke, the piston draws oil, or other liquid, into the bore I! by its passage around the lower valve 20, and on the inward stroke of the piston, the valve 20 is closed and the oil is displaced by raising the upper ball valve 22, flowing through a passage 32 provided in the base l6, and into the bottom of a dome-shaped casing 33, the lower part of the latter having a threaded connection as at 34 with a socket formed in the upper part of the base I6.

'Slidably mounted in the casing 33 is a piston which, when oil is pumped into the bottom of the casing by the means aforesaid, is elevated until the same engages stop shoulders 35 formed with and projecting inwardly from the walls of the casing 33. Above the piston, the closed upper half of the casing contains an expansible fluid, such as nitrogen, under pressure, and when the piston assumes its elevated position in engagement with the shoulders 36, the pressure exerted by the gaseous fiuid on the upper part of the piston 35 may be of the order of 1200 pounds per square inch. The accumulator may be bolted or otherwise fastened to the cowl panel 3| as indicated at 31.

The passage 32 communicates with the oilrecelving lower part of the casing 33 by means of a restricted port 38, the upper part of the bore being surrounded by a fiber seating ring 38, against which the under part of the piston 35 presses when said piston is in its lower position following displacement of a predetermined volume of oil from the lower part of the casing.

Threaded into the open outer end of the pasmeshing gear-toothed rotors 48. Consideration will disclose that when liquid under the pressure of the accumulator is admitted into the chamber 45, positive rotation of the rotors 46 is secured. One of these rotors, as shown in Fig. 4, is p vlded with a spline shaft 41 upon which is mounted for rotation in unison therewith a manually shiftable pinion 48. The splines of the shaft 4! are somewhat helical in order to facilitate engagement and disengagement of the teeth of the pinion 48 with the external teeth of a gear 49 formed with the flywheel or other rotating element of the engine I I.

It is desirable that the pinion 48 should be in meshing engagement with the teeth of the gear 43 when fiuid is admitted into the motor 43 to effect its rotation. Conveniently, this may be accomplished by the provision of a manually reciprocable rod 50 which at one end is pivotally connected as at 5| with a starter lever 52, the latter being pivoted as at 53 intermediately of its length on or in connection with the cowl panel 3| so that it is readily accessible from the pilot's position of the airplane. The opposite end of the rod 50 passes through guide openings provided at one side of the motor casing 44 and terminates within the crankcase 54 of engine II, and to which case the fiuid motor 43 is firmly bolted or otherwise secured as at 55, the case 54 being provided with an opening 55 through which the spline shaft 41 of the motor extends. Connected with the inner end of the rod 50 is a shifter yoke 51, the bifurcated ends of which being received within a groove 58 provided in the hub of the pinion 48. Thus, initial movement of the lever 52 to actuate the rod 50 results first in the engagement of the teeth of the pinion 43 with the engine-carried gear 49.

When this engagement occurs, the inlet valve 59, arranged in the inlet passage 42, is then opened to provide for liquid flow under the gas pressure within the accumulator to enter the motor and rotate its pinion shaft 41'. The inlet Valve, as shown in Fig. 5, is preferably of the balanced pressure type having a head 60 and an annular fluid-transmitting groove 6|. The inlet valve is slidably mounted in a horizontal valve chamber 62 provided in the motor casing, said chamber being closed at one end as at 63 and open at its other. From the inlet valve, there extends a stem 64, which is linked, as at '85, with the rod 50, so that said stem and inlet valve is moved in unison with the rod 50. However, the location of the groove 6| is such that the same does not register immediately with the passage 42 until the pinion 48 is in engagement with the gear 49. When such engagement has been secured, further movement of the inlet valve brings the groove 8| thereof into registration with the passage 42, allowing for liquid travel under pres sure into the rotor chamber of the motor casing 44. Movement of the rod 50 is resisted by a spring 65, so that after the engine has been started, the release of the control lever 52 will result in the inlet valve returning to its position arresting liquid fiow through the inlet 42 and disengaging the pinion 48 from the gear 49. The slight helix angle of the keys of the spline shaft 41 also facilitate this operation. The liquid outlet 8! of the motor 43 is connected by a pipe line 68, which returns the oil to the crank case of the engine In the form of the invention disclosed in Fig. 6, the engine-starting system utilizes oil or other liquid in a closed cycle of flow independent of the lubricating oil of the associated engine. In Fig. 6, the accumulator has clamped thereto a column 69 constituting a liquid reservoir. The lower end of this reservoir is joined by a pipe connection 10 with the bottom of the bore ll of the accumulator. Liquid is maintained in the column 89 to a suitable level, as at H. From the top of the column 69, a pipe line 12 extends to the liquid outlet of the motor 43 In this arrangement, liquid is forced from the accumulator through the pipe line 4| and is transmitted to the motor 43, returning from said motor by way of the pipe line 12 to the column 69 and thence to the liquid inlet of the accumulator. This vapor space 13 of the column 69 may be vented, as at 13', to the atmosphere to relieve abnormal pressures.

In view of the foregoing, it will be seen that the present invention provides a complete selfcontaining and reliable starting mechanism for internal combustion engines, whether used in airplanes or in any other capacity. The starting system may be easily operated by actuating the pump lever 29, which causes the forced flow of the liquid into the bottom of the accumulator casing 33, elevating the piston 35 to a limited extent, as controlled by the shoulders 36, and compressing the gaseous fluid in said casing above the piston. When the control valve 59 of the liquid motor 43 is opened, only a fixed amount of liquid will flow through the motor, the amount being measured by the displacement effected through the limited downward movement of the piston 35. One or more of the casings 33 and pistons 35 may be employed in the construction of the accumulator, depending somewhat on the size or horse power of the associated engine. For light aircraft engines, however, the single casing and piston is all that is usually required. Whil the pump piston 26 has been shown as being manually operated, which it ordinarily is in light aircraft installations, in starting systems adapted for heavier aircraft using proportionately larger engines, the pump piston 26 may be operated by power derived from the engine, eliminating the necessity of hand actuation.

In the form of the invention disclosed in Fig. 1, it has been found desirable to terminate the inlet end of the pipe line It at a given level above the bottom of the engine crank case, so that if the lubricating oil should not be present in proper quantity to obtain desired operation of the engine, the starting system will not function, thus notifying the pilot of the receded oil level. The starting system herein disclosed is readily adaptable to airplane installation without requiring any substantial changes in the design of the engine or other parts.

In the modification of the invention set forth in Fig. 7, the accumulator l has connected therewith a surge chamber 15 in which is slidably mounted a piston 16. The upper side of the piston is provided with a stud ll, forming a guide for the lower end of a coil spring 18, the upper end of this spring being seated in a cup 19 formed with the top wall of th surge chamber. Beneath the piston I6, the surge chamber is filled with the operating liquid used by the starting system, there being a port 80 in the bottom of the surge chamber which communicates with a lower fluid passage 8|. From the passage 8|, a pipe line 82 extends to the fluid outlet of the fluid motor 43, the inlet of said motor being connected by the pipe line 4| with the fitting 40 of the accumulator l5. Also, the passage 8| is connected by a short pipe line 83 with the fitting l8 of the accumulator.

The system shown in Fig. 7 operates after the manner of the system disclosed in Figs. 1 to 5, with the exception that in the event of reverse rotation of the engine and shaft, due to so-called (back-firing, the operation of th fluid motor 43' is reversed, liquid being drawn into the fluid motor from the surge chamber 15 and its pipe line 82, and expelled from the fluid motor by way of the pipe line 4| The liquid pressure thus introduced into the accumulator causes the rise of the piston 26, increasing the gas pressure in the accumulator dome. In this manner, the energy of the "back-firing operation is used advantageously in developing gas pressure within the accumulator which may be utilized in engine restarting operations, as well as protecting the system generally.

The surge chamber 15 is usually filled with oil to the extent indicated in Fig. 7. In the event of back-firing of the associated engine, it will be seen that the oil in the chamber 15 acts as a reservoir in maintaining the pipe line 82 filled with oil, thus furnishing a supp y of oil whichthe liquid motor, functioning as a pump, forces back to the accumulator.

If the pressures developed in the pipe line 4| should cause the main piston of the accumulator to reach its full upward position, excess pressure may be dispelled by the provision of a valved bypass line 85. The valve in this line is set to remain closed until a predetermined abnormal pressure is built up in the pipe line 4 l and when this predetermined pressure is reached, the fluid is by-passed to the supply source. It will be seen thatthe reserve body of fluid in the chamber 15 serves to maintain a sufiicient quantity of fluid to prime the motor 43' when the same is reversely operated and functions in a pump-like manner.

In view of the foregoing, it will be seen that the present invention provides a relatively simple, safe and reliable system for starting various types of internal combustion engines, although specifically the system has been developed for use in starting airplane engines. The apparatus eliminates the use of heavy storage batteries, electric motors, generators and other customary units commonly employed in the starting of internal combustion engines. Our improved apparatus is virtually independent of weather conditions and can be used effectively under cold weather conditions. The starting system may be formed from lightweight metals and will not add substantially to the weight of an airplane.

In Fig. '7 particularly, it will be observed that the piston 26, when forced fully downwardly by gas pressure, seals the restricted port in the bottom of the accumulator chamber and acts as a valve thereon. This movement of the piston eifects a definite displacement of a predetermined amount of liquid, which is suflicient in quantity to impart the desired number of turns to themgine to effect its starting. When the port 90 is closed, the liquid pressure in the pipe line 4 l falls to zero. When advancing upwardly to compress the gas in the accumulator, the movement of the piston is limited by its engagement with the stop shoulders 36. Around the port 90, the bottom of the accumulator chamber may be provided with a fiber or other seating ring 9| with which the bottom of the piston has sealing contact.

We claim:

1. In a fluid-actuated startingv system for internal combustion engines, a servo-motor em- 7 bodying a casing having an internal impeller chamber and fluid inlet and outlet ports in communication with said chamber, rotary impellers mounted in said chamber, a slidable spool-type valve mounted in a valve chamber intersecting said inlet port, said valve being normally positioned so that the body thereof arrests fluid flow through said port into said impeller chamber, said valve being formed with an external annular groove normally spaced from said inlet port, a spline shaft driven by one of said impellers, a gear slidably mounted on said shaft for movement into and out of engagement with a toothed turning member of an associated engine, a slidably mounted manually actuated shaft, means carried by said shaft and connected with said slidable gear for governing the operating positions of the latter with respect to the turning member of the engine, and means carried by said shaft and connected with said inlet valve for actuating the latter simultaneously with said gear, the position of the inlet valve in its chamber being such that said gear will occupy a position of meshing engagement with the teeth of the engine turning member before the annular groove in said valve is registered with said inlet port to admit the-operating fluid into the impeller chamber of said motor.

2. In a fluid-actuated system for starting internal combustion engines as specified in claim 1, in combination with spring means associated with the manually actuated shaft for normally maintaining the shaft in a position in which the slidable motor actuated gear is maintained out of engagement with the teeth of the engine turning member and the annular groove of the inlet valve out of registration with the inlet port leading into the impeller chamber of the motor.

3. In starting apparatus for internal combustion engines of the type employing a fluid-actuated motor for rotating an engine shaft, an accumulator embodying a fluid-receiving chamber,

a piston slidable in said chamber, said chamber on one side of said pistoncontaining a confined body of a compressible gaseous fluid and on the other side of said piston a displaceable liquid, a base for said accumulator having a pump chamber and a fluid transmission passage, the latter at one end being in open communication with the liquid-receiving portion of said accumulator chamber, the other end of said passage being in communication with said starting motor, a manually operated reciprocating pump disposed in said pump chamber, a source of liquid supply, a pipe connection leading from said source of liquid supply to said pump chamber, a check valve in said pump chamber providing for the positive flow of liquid from said source of liquid supply to said pump chamber when said pump is actuated in one direction only, a second check valve normally closing a restricted port establishing communication between said pump chamber and said passage and operative to effect forced flow of liquid from said pump chamber into said passage when said pump is reciprocated in a direction opposite to that em- 8 ployed in producing flow of liquid from said source to said pump chamber, and a manually operated valve for governing the flow of liquid under pressure of the gaseous fluid compressed in said accumulator to said starting motor.

4. In starting apparatus for internal combustion engines of the type having a sump for the reception of lubricating oil and a fluid-actuated starting motor for turning the crank shaft of such an engine, an accumulator unit comprising a base, a cylinder on said base, a piston slidably mounted in said cylinder, said cylinder containing on one side of said piston a displaceabie liquid and on the other side thereof a compressible gas, said base being formed with a fluidconducting passage communicating at one end with the liquid-receiving space of said cylinder, a pipe connection leading from said passage to the fluid-actuated starting motor of an associated engine, said base being formed with a pump chamber, a manually operated pump slidably mounted in said chamber, a pipe connection leading from the oil sump of the associated engine to one end of said pump chamber, a check valve admitting of the flow of liquid from said second pipe connection into said pump chamher when the piston therein is reciprocated in one direction only and to arrest such flow when the piston is reciprocated in an opposite direction, a second check valve normally closing a restricted port establishing communication between said pump chamber and said passage and operable to admit of flow of liquid from the pump chamber into said passage when said pump is reciprocated in a direction in which flow of liquid from said engine sump into said pump chamber is precluded by said first-named check valve, and a manually operated valve onerable to control the flow of liquid from said passage into the starting motor, the opening of said valve providing for the positive displacement of liquid from said cylinderand through said passage under pressure applied to said piston by compressed gaseous fluid contained in said cylinder;

GEORGE CLYDE. KARL F. DAILEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 867,796 Coleman Oct. 8, 1907 1,044,366 English Nov. 12, 1912 1,053,800 Feller Feb. 18, 1913 1,104,058 Marr July 21, 1914 1,117,739 Winton et al Nov. 1'7, 1916 1,209,068 Summerii Dec. 19, 1916 2,150,026 Criiey Mar. 7, 1939 2,170,890 Allen Aug. 29, 1939 2,207,491 Parker July 9, 1940 2,240,011 Casey Apr. 29, 1941 2,290,479 Mercier July 21, 1942

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