US2347744A - Engine starting - Google Patents

Description

May 2,1944.

S. K. LEHMAN ENGINE STARTING Filed Jan. 11, 1945 INVENTOR Samuellf Lela/nan,

ATTORNEY Patented May 2, 1944 ENGINE STARTING Samuel K. Lehman, New York, N. Y., assignor to Bendix Aviation Corporation, Bendix, N. J., a corporation of Delaware Application January 11, 1943, Serial No. 472,082

6 Claims. (Cl. 123-179) This invention relates to engine starting, and particularly to the starting of an internal combustion engine by application of initial turning effort to a rotatable part of such engine.

One commonly used type or starting mechanism employs a flywheel-known in the art as an inertia elementin which starting energy is first stored, then transferred to the engine by way of a reduction gear train and a rotatable Fig. 1 is a diagrammatic representation of a complete system embodying the invention with certain of the component parts in mechanical section; and

Fig. 2 is another diagrammatic view of a portion of the system with certain of the component parts being shown in positions which they occupy at a stage in the operation other than the one illustrated in Fig. 1.

In Fig. 1 the reference numeral 5 designates 55 the flywheel constituting the inertia element above referred to and numeral 6 designates the engine-engaging element, while the numerals I, 8, 9,10,11,12,|3,H,I5,l8,l'l and I8 designate cooperating parts constituting the hydraulic means which I employ in lieu of the usual gear train for converting the relatively high turning effort of the flywheel 5 to a relatively low speed turning effort to be applied to the engine-engagengine-engaging member; the reduction gearing 10 mg member 6. These hydraulic means include a being employed as a means of converting the exreservoir or storage tank 1 for the motive fluid ceptionally high speed of the inertia element to of the hydraulic system, a conduit 8 leading from the relatively low speed at which the initial turnthe storage tank 1 to a pump 9, a conduit to into ing effort must be applied to the engine crankwhich the fluid is discharged after passing shaft. The present invention utilizes this inertia 13 through the pump, conduits II and I2 into which principle of starting an engine, but in a manner the fluid is delivered from the conduit l0 accordto render unnecessary the interposition, between ing to the position of the two-way valve l8, a inertia element and engine-engaging member, of piston l3 movable in a cylinder 2| by fluid adthe usual reduction gear train. 1 mitted to said c linder through conduit l2 and An object of the invention therefore is to prosubsequently ex austed therefrom (upon openvide a novel method of utilizing the inertia prining of the valve I4) to return to the storage ciple for starting an internal combustion engine. tank I by way of the return conduit l5; also av A further object is to provide an engine starthigh pressure relief valve l5 located in a by-pass ing mechanism of the inertia type characterized conduit H to provide a direct return from valve by the absence of the usual reduction gear train I8 to the storage tank 1 in the event of the. de-

between the relatively high speed inertia elevelopment of excessively high pressure in the conment and the relatively low speed engine-engag duit l2 beyond the safe capacity of the cylinder ing element. 2|.

Another object is to provide an engine start- The flywheel 5 is adapted to be energized by ing mechanism'characterized by the employment any suitable means capable oi accelerating the of hydraulic means to drivably connect an inertia said flywheel from zero speed to whatever speed element or other driving member to the member usually a Speed Of 15,000 to 25,000 -iS 18- which actually engages and imparts r tation to quired to store in said flywheel 5 sufficient kinetic the engine, energy to assure, when transferred to the engine These and other objects of the invention will by W y 0! engine-engaging element .the effective become apparent from inspection of the'followstarting of the engine. As shown, the actuating ing specification when read with reference to the means is in the form of an electric motor 24 accompanying drawing wherein is illustrated the whose armature shaft 25 extends bey d the suppreferred embodiment of the invention. It is to porting bearings 26 t0 dlivably receive the inner be expressly understood, however, that the draw- 40 race 21 of a uni-directional clutch (shown as of mg is fo t purpose of illustration only, and is the roller type illustrated in Fig. 8 of Patent No. not designed as a definition of the limits of the 2,301,071 a ted t Romeo M- N d ne n Nom t reference being h t th appended vember 3, 1942), the outer race 29 or said clutch claims for this purpose. being rigidly connected to the flywheel 5 whereby In the drawing: rotation of the armature shaft 25 produces corresponding rotation of the flywheel 5 while permitting overrunning of the flywheel with respect a to the electric motor in the event of application by some other means not shown of. a turning effort for rotation of the flywheel independently of the m otor 24. A storage battery is shown at 3| as a source of energy for the motor 24 and also constitutes a source of energy for.a starting ignition mechanism 32 by which ignition current is supplied to the cylinders of the engine to be started during the cranking period, the unit 32 being ofa type well known in the .artand illustrated, forexample, inFig. 3 of the Nardone patcut above referred to. and. therefore needing no further=description, except to point out that the ing a single plunger assembly 49 to produce concurrent movement: of bridge elements 44 and52 of the,switches'43-44- 45and 5l-52-53, respectively; the contacts 45 and 43 of said switches a being connected to the positive side of the battery circuit, as indicated at 6| and62 inFig. 1, and the selective energization' of the windings 41 and 48 being under the control of a manually operable switch 64 movable to the right and the left 'of a neutral position 66 to produce first an energization of the winding 48 and subsequently an energization of the winding 41. Passage of current through the winding 48 will draw plunger assembly" to the left and thereby close a circuit to the motor 24, the circuit being from the battery 3| to the motor by way of switch 53--525I, and

the result being to produce rotation of the armature shaft 25.and the corresponding energization of the flywheel 5. While this action is occurringthe plunger assembly 49, being in its leftward positionthe switch contact 44 is in the inoperative position and therefore no current passes to the solenoid'31, hence the valve l8 remains in the position indicated in Fig. 1 '31 which position no fluid. is delivered to the cylinder 2|. However, during this period there is. an idle circulation of fluid from tank 1 to pump 9 and back to thevtank by way of conduits l8 and II due to the fact thatone of the working elements 1| of the pump (and it may be noted here that while a pump of the spur gear type is illustrated, any other suitable type may be substituted) is directly connected to the flywheel 5 by a shaft 12 which has driving connection with both the element 1 I and the hub 13 of the flywheel. This driving con- .nection causes the pump elements and 1| to rotate with the flywheel and thus draw fluid from the tank 1 and cause the return of such fluid to the tank by way of the conduits l8 and II, but as no actual work is being performed other than to move the. fluid against what little friction there may be in the parts over which the fluid passes, this fluid circulating action does not appreciably afiect the process of acceleration of the flywheel 5 to the predetermined degree. When this process of acceleration is completed, the operator will throw the switch64 to the opposite extreme position thereby breaking the circuit to the winding 48 and establishing a new path of flow to thewinding 41. The result is to interrupt the flow of current to the motor and to produce a new path of flow, the new path being to the units 32 and 31 by way of the contact 44 which now bridges thecontacts 43 and 45 and from which point the current passes in the parallel path Al and" to the units 32 and 31, respectively. Passage of current to the unit 32 initiates the operation of the charge igniting means in the cylinders of the engine and concurrently the passage of current to the winding 36 of the unit 31 operates toshift the linkage 38 and 39 of the solenoid into the position indicated in Fig. 2, in which position the two-way valve l8 cuts off flow into the conduit II and establishes a new path of flow directly from conduit II! to the conduit l2 leading to the cylinder 2| wherein is located the piston l3. While any suitable means may be employed for translating the rectilinear movement of thepiston'l3 into, first, aforward meshing movement of the engine-engaging element 6 to establish driving connection with the corresponding element 6a attached to the rotatable element 6b of the engine to be started, and, secondly, to produce rotation of the said elements 6 and 6a after they have become inter-engaged, the mechanism indicated for this purpose in the drawing is of the type'more fully illustrated and described in Patent No. 2,298,117 granted to Romeo M. Nardone on October 13, 1942. As shown in the Nardonepatent just referred to, such motion translating means. includes a central tubular member 51a terminating in a solid portion receiving elements corresponding to those shown at 51 and 58 in the Nardone patent which elements are adapted to impart a forward thrust to the engine-engaging element 6 in response to the initial forward motion of the piston I3 upon entry of the fluid to the cylinder by way of the inlet port. BI; and the motion translating mechanism further includes an internally threaded driving sleeve 24a adapted to move forward with the piston l3 and thus produce rotation of the engineengaging member 6 by reason of the inter-engagement of its internal threads with the external threads of a member corresponding to the driven sleeve 22 of the said Nardone patent.

As the rotation (cranking) proceeds, the engine will pick up on its own power, and at the conclusion of the forward movement of the piston l3 the collar 53a on the piston l3 impinges against the head (not shown, but corresponding to the head 52 shown in the said Nardone patent) of the stem 46a. of the exhaust valve l4 and moves the said valve I4 away from the circular seat formed in the valve housing 44a, and thereby opens a path by which the fluid which has previously been admitted to the cylinder 2| can flow back to the tank 1 by way of the return conduit l5 which leads from the right-hand portion of the valve chamber 440, back to the tank. As the fluid is thus exhausted from the cylinder 2| the coiled spring 310, which was compressed during the forward movement of the piston I3, expands and thus drives the piston I 3 back to the position indicated in Fig. 1. Upon reaching this home position-the member 6 being meanwhile de-meshed by the means 51, 58 of the Nardone patent-the collar 53 cooperates with the shoulder 41a on the neck portion of the valve l4 to move the valve back to the seating (flow interrupting) position indicated in Fig. 1, thereby restoring the hydraulic motor to condition for the next starting operation. To insure against a premature reclosing of the valve I4 there is provided a spring'48a yieldably holding the valve l4 in the open position until closed by the positive action of the collar 53a against the shoulder 41a above described.

As the engine becomes self-operative, in response to the cranking action, the operator will of course return the switch to the neutral (mid-way) position, thus deenergizing units 32 and 31, and permitting spring 95, in housing 31, to return valve 18 to the Fig. 1 position; but even if opening of the circuit is delayed (as by inadvertence) no harm will result, as the pressure will soon be reduced to zero by reason of exhaustion of the energy stored in the flywheel 5, and transferred from there to the pump 9.

The engine having started, unit 32 (bein merely a starting auxiliary) need no longer function, as ignition current is furnished by a conventional magneto (not shown) during the entire operating period of the engine, once the latter has been effectively started.

What is claimed is:

1. The method of starting an internal combustion engine which comprises, first, accelerating an inertia mass to a relatively high speed, secondly, converting the kinetic energy thus stored into hydraulic pressure, and simultaneously applying said hydraulic pressure to a part adapted to drive a relatively low speed engineengaging member.

2. The method of starting an internal combustion engine which comprises, first, accelerating an inertia mass to a relatively high speed, secondly, converting the kinetic energy thus stored into hydraulic pressure, and simultaneously applying said hydraulic pressure to a part adapted to drive a relatively low speed engineengaging member and supplying ignition current to the engine during the period of rotation by said engine-engaging member.

3. In an inertia starter for internal combustion engines, an inertia member, means for accelerating said inertia member to relatively high speed, an engine-engaging member and hydraulic means for converting the high speed rotation of the inertia member into low speed rotation of said engine-engaging member.

4. In an inertia starter for internal combustion engines, an inertia member, means for accelerating said inertia member to relatively high speed, an engine-engaging member, hydraulic means for converting the high speed rotation of the inertia member into low speed rotation of said engine-engaging member, said hydraulic means including a cylinder having a piston therein, a liquid reservoir, means including a pump connecting said reservoir to said cylinder, and means for drivably connecting said inertia member to said pump.

5. In an inertia starter for internal combustion engines, an inertia member, means for accelerating said inertia member to relatively high speed, an engine-engaging member, hydraulic means for converting the high speed rotation of the inertia member into low speed rotation of said engine-engaging member, said hydraulic means including a cylinder having a piston therein, a liquid reservoir, means including a pump connecting said reseflloir to said cylinder, means for drivably connecting said inertia member to said pump, and means for causing the liquid to bypass said cylinder until the inertia member is suificiently accelerated.

6. In an inertia starter for internal combustion engines, an inertia member, means for accelerating said inertia member to relatively high speed, an engine-engaging member, hydraulic means for converting the high speed rotation of the inertia. member into low speed rotation of said engine-engaging member, said hydraulic means including a cylinder having a piston therein, a

liquid reservoir, means including a pump connecting said reservoir to said cylinder, means for drivably connecting said inertia member to said pump, means for causing the liquid to by-pass said cylinder until the inertia member is sumciently accelerated, and additional by-pass means including a conduit having a normally closed valve therein, said valve being yieldable to bypass llquid directly back to the reservoir in response to exertion of a predetermined pressure upon said valve.

SAMUEL K. LEHMAN.

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