US2292189A - Starting system for compression ignition engines - Google Patents

Description

Aug. 4, 1942. E. R. WITZEL 2,292,189

STARTING SYSTEM FOR COMPRESSION IGNITION ENGINES Filed Oct. 6, 1941 7 Patented Aug. 4, 1942 UNETED STATES PATENT OFFICE STARTING SYSTEM FOR COMPRESSION IGNITION ENGINES 9 Claims.

My invention relates to improvements in a starting system for compression ignition engines, and the objects of my invention are, first, to provide means for starting and stopping a compression ignition engine by remote control and, secnd, to provide safety means for preventing the mal-functioning of said starting means.

With the foregoing related objects in view the improvement resides in the mechanism and circuits illustrated in the accompanying drawing, in which the single figure is a diagrammatic view of the mechanism and circuits involved.

In the drawing the numeral I indicates a starting switch, preferably of the push button type, which, when operated, closes a circuit from storage battery 2 through lead 3, ammeter 4, lead 5, contact I i of control relay A, lead 6, starting switch 8, lead 7, relay coil 8 of control relay A, resistor 9, normally closed contact In of thermal switch B and lead H to ground. Since the negative terminal of the battery 2 is grounded, this completes the circuit.

The energization of coil 8 causes the normally open armature IE to close, closing a circuit between contacts l3 and I l. Current then flows from contact l4 through armature l2, lead l5, coil 8, resistor 9, contact If! and lead H to ground, thus icy-passing starting switch I and maintaining the armature l2 closed even though the starting switch I' is opened. The closing of starting switch I thus need be only a momentary contact, and it is designed to return to the open position automatically as soon as the manual pressure on it is released.

The closing of armature [2 establishes a circuit from contact i l through lead l6, contact ll, normally closed armature l8 and contact IQ of voltage relay C, leads 20 and 2|, normally closed switch 12, lead 23, solenoid 24, lead 25, resistance 26 of thermal switch B and lead II to ground.

Current also passes from armature it through leads 2'! and 28, normally closed contacts 29 of oil' pressure switch D, lead 30, starting relay coil 3| and lead 32 to ground.

The energization of relay coil 3| closes the armature 33, closing a circuit from the battery 2 through the starting motor 34, thus causing the starting motor to crank the engine.

The energization of solenoid 24 draws the plunger 36 upward, placing tension on coil spring 31, which is attached thereto and to a bell crank lever 39, causing the latter to be drawn upwardly and to supply the engine with fuel for starting as hereinafter described.

Battery current now flows through four parallel paths which include relay coil 8, fuel solenoid coil 2t, starter relay coil 3|, and starting motor 34.

In order to prevent the discontinuation of cranking should the oil pressure switch D open the contact 29 before the engine starts to operate under its own power, a by-pass resistor 4! is connected between leads 28 and 30. This resistance is of such ohmage as to permit sufiicient current to pass to retain the armature 33 in closed position but to prevent the passage of sufficient current to close the armature 33 when in the open position and the contact 29 is open This provides a safety feature which prevents the starter from being operated before the engine has come to a complete stop.

A battery charging generator 42, driven by the engine, is connected by lead 43 to coil 44 of voltage relay C, the opposite extremity of which is grounded by means of lead 45. Preferably a resistance 45 is inserted in the circuit to minimize the effects of temperature upon the impedance of coil 44.

At a predetermined engine speed the current from the battery charging generator 42 becomes sufficient to energize the coil 44 and open the armature IS, opening the circuit between contacts I! and I9. However, a reduced current still flows through a by-pass circuit including the resistance 41 suificient to keep the solenoid 24 energized and retain the plunger 36 in its raised po sition. The opening of armature I8 also breaks the circuit to lead 21, thus de-energizing starting relay coil 3| and opening the circuit to the starting motor 34.

Stopping of the engine is accomplished by closing the stopping switch 5| which, like starting switch I, is preferably of the push button selfopening type. The closing of stopping switch 5| short-circuits relay coil 8 through leads I and 52, resistor 9 being in circuit to prevent excessive currents. This short-circuit need be of only momentary duration, sufficient to allow the armature I2 to open the circuit between contacts [3 and I4 breaking the circuit through solenoid 24 and releasing plunger 36 which returns to its original position, shutting off the supply of fuel to the engine and causing it to stop.

The battery charging generator 42, driven by the engine, has a reverse current relay of conventional design in circuit therewith.

The control relay A may be of any type adapted to close a circuit when energized and to open the circuit automatically when de-energized.

The voltage relay C may likewise be of any type adapted to open a circuit when energized and to close the circuit automatically when de-energized.

The oil pressure switch D may be of standard construction comprising an expansible bellows in communication with the pressure oil supply of the engine whereby increase in the oil pressure causes an expansion of bellows 48 and an opening of switch 29. While I prefer to use an oil pressure switch for the aforementioned purpose, it will be apparent that equivalent means such as a governor-operated switch, a solenoid responsive to a certain voltage, etc. may be used to open the circuit upon the attainment of a predetermined engine speed.

The thermal switch B is of conventional design adapted to open the circuit after a predetermined time in case the engine fails to start, thus preventing complete discharge of the battery. One type of thermal switch suitable for the purpose isv that disclosed in United States Patent No. 1,853,957, issued April 12, 1932, to Anton Frank Brotz.

Control of fuel supply is provided by the following arrangement:

The coil spring 31 is attached, at one extremity, to the plunger 36 of the solenoid 24 and, at the other extremity, to the arm 38 of the bell crank lever 39; a coil spring54 is attached, at one extremity, to the frame of the engine or other solid support and, at the other extremity, to the arm 38 of the bell crank lever 39 in such a manner that the spring 54 opposes the action of the spring 31.

A coil spring 56 is attached, at, one extremity, to the arm 55 of bell crank lever 39 and, at the opposite extremity, to one extremity of the pivot arm 51 which is pivoted at 58 to the frame or other solid support. The opposite extremity of the pivot arm 51 is pivotally attached at .11 to one extremity of the lever arm 59 which has pivotal attachment at 60 tothe sleeve 6| and at 62 to the fuel rack bar 63.. The fuel rack bar 63 is provided with gear teeth meshing with the pinion 64 of fuel injector 65. Advancement or retraction of the bar 63 causes rotation of the pinion 64 and causes the fuel injector to deliver more or less fuel in a manner which is well known in the compression ignition engine art and which, since it forms no part of the present invention, is not specifically illustrated or described herein. A stop screw 66 is provided to prevent movement of the bar 63 past the position where the fuel supply is fully closed.

The sleeve 6| is slidably mounted on the shaft 61 which may be a cam shaft or other shaft rotating in accordance with the speed of the engine, and, at one extremity, abuts the compression spring 68. At its opposite extremity the sleeve 61 abuts the lugs 69 of a pair of governor weight arms .19 which are mounted on the shaft 61 so as to rotate therewith.

The arrangement is such that spring 54 is normally under some tension, thus holding the arm 38 in a lowered position when the solenoid 24 is not energized, placing spring 56 under compression and turning pivot arm 51 clockwise, causing lever arm 59 to hold the fuel rack bar 63 in a closed position.

When the solenoid 24 is energized, as hereinabove described, the plunger 36 is drawn upwardly, placing tension on spring 31 and drawing the bell crank leverv arm 38 upwardly against the tension of spring 54. Spring 56 is made of heavy wire, hence does not change length readily and transmits the motion of arm 55 of the bell crank lever 39 to the pivot arm 51, causing it to pivot counter-clockwise moving the pivot point 11 and rotating the lever arm 59 clockwise about the pivot 60, thus moving the fuel rack bar 63 to the fully open position.

If sufficient upward torque is exerted on bell crank arm 38 after the fuel rack bar 63 is in the open position, then sleeve 6| is moved on the shaft 61 by the pressure on pivot arm 51. Thus spring 68 is under compression and spring 56 under tension with the pivot point 60 stopping at an intermediate position and fuel rack 63 in the open position.

However, spring 31 is under only moderate tension which is not sufiicient to compress spring 68 appreciably. The fuel rack bar 63 is moved to the fully open position without a full movement of arm 38 because of the extreme strength of springs 56 and 68 in their respective positions.

When the engine begins running the shaft 61 rotates and, as the speed increases, the governor weight arms 10 are forced outwardly by centrifugal force causing the lugs 69 to move the sleeve 6| on the shaft 61 against the compression of the Spring 68.

As spring 68 is compressed by the joint action of the governor and spring 31, arm 38 finally reaches a point where it contacts the contact arm 12 raising it and separating contacts 48 and opening the circuit through leads 2| and 23, thus further reducing the current through solenoid 24 by reason of the incorporation of resistance 49, previously by-passed, in the circuit thereto. This reduced current through the solenoid 24 continues during the running period of the engine. While I prefer to use the construction described, it will be obvious that any equivalent means for opening the circuit upon the attainment of a predetermined engine speed such as a voltage coil or oil pressure switch may be used if desired.

A stop screw 13 limits the upward motion of the arm 38 and is set to allow the contact arm 12 to open before the stop screw 13 stops the movement.

Due to the reaction of spring 56, the pivot point 11 reaches a fixed running position whereupon lever arm 59 becomes a third class lever with fulcrum at 1|, power applied at 60 and fuel rack bar 63 as the load. Movement of the sleeve El now causes a corresponding movement of the fuel rack bar 63, and as the sleeve 6| is moved against the compression of the spring 68 by the governor arms 19 the rack bar 63 is moved toward the closed position, slowing down the speed of the engine. At slower speeds when the governor arms 10 are unable to hold the sleeve 61 against the pressure of the spring 68, the reverse action takes place. Thus the engine runs at a constant speed. .Thespeed may be adjusted by varying the tension of spring-68 by means of adjusting screw 14.

It will be noted that. the solenoid 24 is impressed with the full battery voltage upon starting the plant, when the plunger 36 must open against the full force of springs 54 and .68, and that later, when the centrifugal Weights 10 oppose the forces tending. to shut off the fuel, the current through solenoid 24 is reduced by the incorporation in the circuit of resistances 41 and 49, thus reducing the current outlay since not as much current is required to hold the plunger 36 retracted as to retract it. It will be obvious that the mechanical governor disclosed may be replaced by an electrical governor or similar speed responsive device. However, when the solenoid 24 is deenergized by actuating the stop switch as above described, the combined action of springs 54 and 68 is sufiicient to return the apparatus to its original position shutting off the fuel supply.

The system is not necessarily limited to a single starting switch and a single stop switch, since a number, connected in parallel as shown by the dotted lines in the illustration, may be used where circumstances make it desirable to provide control stations at more than one point, and it is obvious that the starting and stopping switches may be placed in proximity to the engine or remote therefrom as circumstances may make most convenient.

The specific details herein disclosed are for the purpose of illustration only, and I do not desire to limit myself to said details, as it is obvious that various modifications may be made therein without departing from the essential features of the invention, as defined in the appended claims.

I claim:

1. In a starting system for compression ignition engines, the combination of a compression ignition engine, a fuel injector adapted to supply i'uel thereto, means for adjusting the quantity of fuel delivered by said injector, means actuating said adjusting means comprising a solenoid coil adapted, when energized, to close a plunger attached to said adjusting means whereby to move said adjusting means toward the open or fuel-supplying position, means tending to move said adjusting means toward the closed position, and means responsive to the speed of the engine tending to vary the position of said adjusting means in accordance with the speed of the engine, the relationship of the aforesaid means being such that the fuel adjusting means occupies a closed position when the solenoid is de-energized and the engine at rest, occupies an open position to provide sufficient fuel for starting when the solenoid is energized and the engine at rest, occupies a position to provide fuel to maintain a predetermined speed of the engine when the solenoid is energized and the engine in operation and occupies a closed position when the solenoid is de-energized while the engine is in operation, a battery, means operated by current from said battery for cranking said engine, means operable upon closing of a starting switch for establishing a circuit from said battery through said cranking means and a circuit from said battery through said solenoid, means operative upon the attainment of a predetermined engine speed for discontinuing the circuit through said cranking means, means operative upon the attainment of a predetermined engine speed for reducing the current through said solenoid to that required to hold said plunger in the closed position, and means for discontinuing the circuit through said solenoid whereby to cause said fuel adjusting means to shut off" the supply of fuel and stop said engine.

2. In a starting system for compression ignition engines, the combination of a compression ignition engine, a fuel injector adapted to supply fuel thereto, means for adjusting the quantity of fuel delivered by said injector, means actuating said adjusting means comprising a solenoid coil adapted, when energized, to move said adjusting means toward the open or fuel-supplying position, means tending to move said adjusting means toward the closed position, and means responsive to the speed of the engine tending to vary the position of said adjusting means in ac cordance with the speed of the engine, the relationship of the aforesaid means being such that the fuel adjusting means occupies a closed position when the solenoid is de-energized and the engine at rest, occupies an open position to provide sufiicient fuel for starting when the solenoid is energized and the engine at rest, occupies a position to provide fuel to maintain a predetermined speed of the engine when the solenoid is energized and the engine in operation and occupies a closed position when the solenoid is de-energized while the engine is in operation, a battery, means operated by current from said battery means operated by current from said battery for cranking said engine, means operable upon closing of a starting switch for establishing a circuit from said battery through said cranking means and a circuit from said battery through said solenoid, means operative upon the attainment of a predetermined engine speed for discontinuing the circuit through said cranking means, and means for discontinuing the circuit through said solenoid whereby to cause said fuel adjusting means to shut off the supply of fuel and stop said engine.

3. In a starting system for compression ignition engines, the combination of a compression ignition engine, a fuel injector adapted to supply fuel thereto, means for adjusting the quantity of fuel delivered by said injector, means comprising an electrical coil for varying said adjusting means to supply fuel to the engine, a battery, means operated by current from said battery for cranking said engine, means operable upon closing a starting switch for establishing a circuit from said battery through said cranking means and a circuit from said battery through said elec-- trical coil, means for preventing the establishment of said circuit from the battery through the cranking means while the engine is in operation, means for opening the circuit through said cranking means in case the engine fails to start after a predetermined period of cranking, means operative upon the attainment of a predetermined engine speed for discontinuing the circuit through said cranking means, means responsive to the speed of the engine to further vary said adjusting means to regulate the supply of fuel whereby to maintain a predetermined speed of said engine, means for discontinuing the circuit through said electrical coil and means for causing said fuel adjusting means to return to a fuel supply closing position upon discontinuance of the circuit through said electrical coil.

4. In a starting system for compression ignition engines, the combination of a compression ignition engine, a fuel injector adapted to supply fuel thereto, means for adjusting the quantity of fuel delivered by said injector, means comprising an electrical coil for varying said adjusting means to supply fuel to the engine, a battery, means operated by current from said battery for cranking said engine, means operable upon closing a starting switch for establishing a circuit from said battery through said cranking means and a circuit from said battery through said electrical coil, means for preventing the establish ment of said circuit from the battery through the cranking means While the engine is in operation, means operative upon the attainment of a predetermined engine speed for discontinuing the circuit through said cranking means, means responsive to the speed of the engine to further vary said adjusting means to regulate the supply of fuel whereby to maintain a predetermined speed of said engine, means for discontinuing the circuit through said electrical coil, and means for causing said fuel adjusting means to return to a fuel supply closing position upon discontinuance of the circuit through said electrical coil.

5. In a starting system for compression ignition engines, the combination of a compression ignition engine, a fuel injector adapted to supply fuel thereto, means for adjusting the quantity of fuel delivered by said injector, means comprising a solenoid coil for varying said adjusting means to supply fuel to the engine, a battery, means operated by current from said batter for cranking said engine, means operable upon closing of a starting switch for establishing a circuit from said battery through said cranking means and a circuit from said battery through said solenoid, means operative upon the attainment of a predetermined engine speed for discontinuing the circuit through said cranking means, means responsive to the speed of said engine to further vary said adjusting means to regulate the supply of fuel whereby to control the speed of said engine, manually operated means for discontinuing the circuit through said solenoid and means for causing said fuel adjusting means to return to a fuel supply closing position upon discontinuance of the circuit through said solenoid.

6. In a starting system for compression ignition engines, the combination of a compression ignition engine, a fuel injector adapted to supply fuel thereto, means for adjusting the quantity of fuel delivered by said injector, means comprising a solenoid coil for varying said adjusting means to supply fuel to the engine, a battery, means operated by current from said battery for cranking said engine, means operable upon closing of a starting switch for establishing a circuit from said battery through said cranking means and a circuit from said battery through said solenoid,

means operative upon the attainment of a prede- I termined engine speedfor discontinuing the circuit through said cranking means, means responsive to the speed of said engine to further vary said adjusting means to regulate the supply of fuel whereby to control the speed of said engine, manually operated means for discontinuing the circuit through said solenoid, and means for causing said fuel adjusting means to return to a fuel supply closing position upon discontinuance of a circuit through said solenoid.

'7. In a starting system for compression ignition engines, the combination of a compression ignition engine, a fuel injector adapted to supply fuel thereto, means for adjusting the quantity of fuel delivered by said injector, means comprising a solenoid coil for varying said adjusting means to supply fuel to the engine, a battery, means operated by current from said battery for cranking said engine, means operable upon closing of a starting switch for establishing a circuit from said battery through said cranking means and a circuit from said battery through said solenoid, means for discontinuing the circuit through said solenoid and means for causing said fuel adjusting means to return to a fuel supply closing position upon discontinuance of the circuit through said solenoid.

8. In a starting system for compression ignition engines, the combination of a compression ignition engine, a fuel injector adapted to supply fuel thereto, means for adjusting the quantity of fuel delivered by said injector, means operable upon closing of a starting switch for varying said adjusting means to supply fuel to the engine, means responsive to the speed of said engine to further vary said adjusting means to regulate the supply of fuel whereby to control the speed of said engine, and means actuated by closing a stopping switch for varying said adjusting means to cut off the supply of fuel whereby to stop said engine.

9. In a starting system for compression ignition engines, the combination of a compression ignition engine, a fuel injector adapted to supply fuel thereto, means for adjusting the quantity of fuel delivered by said injector, means operable upon closing of a starting switch for varying said adjusting means to supply fuel to the engine. means responsive to the speed of said engine to further vary said adjusting means to regulate the supply of fuel whereby to control the speed of said engine and means for varying said adjusting means to cut off the supply of fuel whereby to stop said engine.

EARL R. WITZEL.

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