US2054987A - Automatic starter control - Google Patents

Description

Sept. 22, 1936. I P MAURER 2,054,987

AUTOMATIC STARTER CONTROL Filed May 12} 1934v T INVENTOR Patented Sept. 22, 1936 AUTOMATIC STARTER CONTROL Paul H. Maui-er, Elmira, N. Y.,. assignor to Echpse Machine Company, Elmira, N. Y., a corporation of New York Application May 12, 1934, Serial No. 725,371

2 Claims.

The present invention relates to an automatic starter control for internal combustion engines and more particularly to a device of the socalled ignition key starter type in which cranking is initiated by closure of the ignition switch,

and thereafter the starting mechanism is controlled automatically to keep the engine running as long as the ignition switch remains closed.

In devices of this type in which electromagnetic means energized from an enginedriven generator are used to prevent operation of the starting mechanism, some difficulty has been encountered in certain installations in designing said electromagnetic means, or so-called lock-out coil, so as to be sufficiently sensitive to prevent actuation of the starting mechanism at the slowest idling speed of the engine, Without overheating under normal charging conditions and without appreciably affecting the charging performance of the generator.

For example, in a typical six volt starter control in which the generator lock-out coil has a resistance of about fifteen ohms, there is no over 5 heating and the look-out function is effective down to about 0.15 volt corresponding to about 220 R. P. M. of a commercial type of generator, which is satisfactory for many installations. In some installations, however, in which the drive 30 ratio from the engine to the generator approaches unity, it is desirable for the lock-out coil to be effective at considerably slower generator speeds, and it has been found that a lockout coil of about two ohms resistance may be 35 made effective down to about 0.06 volt corresponding to a generator speed of about 95 R. P. M. This is quite satisfactory as respects the lockout function, but the continued application of full generator voltage overheats such a coil,

40 and the minimum charging speed of the generator is raised fifty to seventy-five R. P. M. which is undesirable.

It is an object of the present invention to provide a novel automatic starter control embody- 45 ing improved lock-out means for preventing actuation of the starting mechanism while the engine is self-operative.

It is another object toprovide such a device of the type utilizing current from an engine- 50 driven generator for maintaining the starting mechanism inoperative, embodying provisions for increasing the sensitivity and reliability of the generator control.

. It is a further object to provide such a device 65 which is adapted for use with ordinary comly the operation of any of the units of the com- 10 bination in which it is incorporated.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing in which the single figure illustrates in a semi- 15' diagrammatic form a preferred embodiment of the invention.

Referring to the drawing, there is illustrated an electrical system for an internal combustion engine, not shown, comprising a starting circuit 20 including a battery I grounded at 2 and connected by a lead 3 to a magnetic starting switch 4 which in turn is connected by a lead 5 to a starting motor SM grounded at 6 to complete the starting circuit. An engine-driven generator G is also illustrated, which is arranged during self-operation of the engine to charge the battery 1 by means of a lead i connected through ammeter A to the battery lead 3, the charging operation being controlled by a cut-out or reverse current relay 8 of the usual type.

A control circuit for the magnetic starting switch is provided including battery lead 3, manual switch s, which is preferably the ignition switch of the engine, lead ll, solenoid I2, lead it, fixed contact I4 and movable contact l5 which is mounted on a spring strip l6 grounded at l! to complete the control circuit.

Electromagnetic means are provided for holding open the control contacts l4, I5 during selfoperation of the engine responsive to voltage produced by the generator G. As here illustrated, this means comprises a solenoid or lock-out coil l8 mounted on a fixed pole piece l9 and arranged to attract a reciprocable plunger 2! which is normally maintained in upper position as illustrated by means of a spring 22. Plunger 2!, when pulled downward into engagement with the pole piece I9, actuates a bell crank lever 23, causing a roller 24 on the outer end thereof to engage a Weight member 25 on the end of the spring strip i6 and bend the same backward to maintain contact l5 out of engagement with contact l4. Solenoid I8 is connected in circuit with generator G by means of a lead 26 connecting one end of the for completing the look-out circuit. Closure of the starting circuit is thus prevented by the energization of solenoid M3 to a predetermined degree corresponding to the idling speed of the engine.

According to the present invention, the solenoid I8 is designed to perform its lock-out function effectively and reliably by means of current supplied by the generator when rotating at the slowest idling speed of the engine, and means controlled by said solenoid are provided for protecting the solenoid from the excess voltage produced by the generator under charging condi tions which would otherwise cause overheating and adversely afiect the generator performance. For this purpose a resistor 28 having a value such as to suitably limit the current passing through the solenoid I8, is connected between the lead 21 and the ground, and means in the form of normally closed contacts 29 and 3| are provided for short-circuiting said resistance when the voltage of the generator G is below a predetermined value, said contacts being arranged to be opened when the solenoid I8 is energized by generator voltage above said predetermined value.

As here illustrated, contact 3| is mounted on a rigid conducting bracket 32 which is grounded at 33, while contact 29 is mounted on a conducting spring strip 3 connected to the solenoid ground lead 21. A magnetic armature 35 is mounted on a spring strip 36 and is provided at, its free end with a block of insulation 31 adapted to engage the free end of the contact strip 34 and move contact 29 out of engagement with contact 3|. Armature 35 is arranged'to surround the magnetic plunger 2| with comparatively small clearance and forms a magnetic bridge substantially completing the magnetic circuit of the solenoid l8, which, circuit comprises pole piece I 9, the container or box 38, a partition 39 in said box and the plunger 2|. It will be noted that a substantial opening is provided at ill for the plunger 2| where it traverses the partition 39, and the armature 35 is arranged to bridge said opening. This causes a large proportion of the flux traversing the magnetic circuit of the solenoid l8 to flow through the armature 35 When the solenoid is energized to a predetermined degree higher than that correspondingto engine idling, the armature is therefore pulled down against the partition 39, thus opening contacts 29, 3|.

' Substantial lost motion indicated at 42 is provided between the block of insulation 31 and the end of the spring strip 34 in order that the contacts 29, 3| shall not be opened until the armature 35 has been pulled down quite close to the partition 39. This arrangement insures against the possibility of a fluttering action of contacts voltage.

29, 3| due to the introduction of the resistor 28 in the circuit of solenoid l8 by the opening of said contacts and the consequent weakening of the solenoid. 1

It will be understood that the spring strip 36 forming the mounting for the armature 35 has sufiicient stiffness to insure release of the armature 35 and closure of contacts 29, 3| at a substantially higher voltage of the generator G than the voltage at which plunger 2| will be released to permit closure of the control contacts I l, l5. The voltage at which the armature 35 is pulled down to open contacts 29, 3| is, however, preferably substantially below the charging voltage of the generator in order that the solenoid l8 may be adequately protected from such charging The combined resistance of the solenoid l8 and the resistor 28 is preferably equal to or greater than the resistance of the ordinary generator lock-out coils used in automatic starter controls of this character, so that the rotational speed of the generator at which charging commences is not increased by the use of the present device as compared to the ordinary less sensitive types of starter controls.

In one satisfactory embodiment of this invention, for example, the look-out coil l8 has a resistance of about two ohms, the resistor 28 has a value of about thirteen ohms, the short-circuiting contacts 29, 3| open at about 4.5 volts, and close at about 3 volts, and the relay plunger is released at about 0.06 volt; Since the resistance of the lock-out circuit external to the generator is raised to fifteen ohms by the insertion of the resistor before the generator gets up to charging speed, the minimum charging speed of the generator is not appreciably increased by this device.

In the operation of this device'and starting with the parts in the positions illustrated, closure of the ignition switch 9 completes the control cir-' cuit through battery I, lead 3, ammeter A, lead 1|, switch solenoid l2, lead l3, contacts. |4, |5,

spring strip l6 and ground connection H. The consequent energization of the switch solenoid l2 causes closure of the starting switch 4, thus completing the starting circuit and causing the engine to be cranked.

When the engine becomes operative, the plunger 2| is attracted against'the pole piece l9, opening control contacts I4, I 5, and is retained in'that position'by the energization of the solenoid |8 by the engine-driven'generator G. When the engine is running at or near such speed as to causethe generator to charge the battery, the solenoid I8 is energized sufficiently to hold the armature 35 against the partition 39, whereby contacts 29, 3| are held open and the resistor 28 is put in series with the solenoid l8, thus protecting the same against the full voltage of the generator. When the engine slows down nearly to idling speed,the weakening of the solenoid l8 by the reduction in the generator voltage permits the armature 35 to pull away from the partition 39 and allow contacts 29, 3| to close, thus short-circuiting the resistor 28 and permitting all the voltage then produced by the generator to be applied to the solenoid l8, thus insuring against release of the plunger 2| during slow idling of the engine. Should the engine stall for any reason, however, the complete failure of generator voltage causes deenergization of the solenoid 8 whereby the plunger 2| is released, permitting the control contacts l4, IE to close and cause the starting operation to be repeated.

Although but one embodiment of the invention has been shown and described in detail, it will be understood that other embodiments are possible and various changes may be made in the details and arrangements of the parts without departing from the spirit of the invention defined in the claims appended hereto. 7

What is claimed is: V

1. In an electrical system for internal combustion engines a starting system including a magnetic starting switch, an engine-driven generator,

,a control circuit for said starting switch including normally closed contacts, electromagnetic means including a plunger responsive to a predetermined voltage of the generator for holding open said contacts, an armature'surrounding said plunger and arranged to be attracted by said electromagnetic means, a resistor, and contacts for causing said starting switch to open, and means energized by said generator for preventing closure of the starting switch, a resistor in series with said generator-energized means, means including an armature and contacts controlled thereby actuated during cranking by the batteryenergized means and during self-operation of the engine by the generator-energized means for short-circuiting said resistor upon energization of said electromagnetic means below a predeter- 10 mined minimum.

PAUL H. MAURER.

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