US2949906A - Engine control system and apparatus - Google Patents

Description

Aug. 23, 1960 Filed June 2, 1958 MM v R. H. VOIGT ENGINE CONTROL SYSTEM AND APPARATUS 3 Sheets-Sheet 1 ROBERT H. VOIGT INVENTOR.

BYW

ATTORN EY Aug. 23, 1960 R. H. VOIGT ENGINE comm. sysmu AND APPARATUS 3 Sheets-Sheet 2 Filed June 2, 1958 ROBERT H. VOIGT INVENTOR. Byghwr/nd/i fgrw ATTORNEY OIL PUMP PRESSURE P.$.l.

Aug. 23, 1960 R. H. VOIGT ENGINE CONTROL SYSTEM AND APPARATUS Filed June 2, 1958 3 Sheets-Sheet 3 FIG. 5

Is STOP RING v ENGAGES PLATE coNTAcTs CLOSED i END OF DIAPHRAGM FREE MOTION SWITCH BLADE Z 1 s5 sows I I l i l I l 1 l l l l I I I I I I I I I I I I00 90 so 10 so 5o 40 30 20 ID 0 NORMALLY OPEN FIRST SWITCH A IN IoooTI-Is. INCHES.

ROBERT H. VOIGHT INVENTOR.

BYWMM ATTORNEY ENGINE CONTROL SYSTEM AND APPARATUS Robert H. Voigt, Milford, Mich., assignor to Tokheim Corporation, Fort Wayne, Ind., a corporation of Indiana Filed June 2, 1958, Ser. No. 739,336

19 Claims. (Cl. 123-179) This invention relates to an electrical control system for starting and maintaining the operation of an internal combustion engine and for stopping said engine upon failure ofthe engine lubricant pressure.

' It is a primary object of the inventionto provide a control system and switching apparatus which will energize the electric fuel pump of an engine prior to energizing the engine starting motor, so that substantially full battery voltage will be available for starting the pump and so that the fuel charging apparatus will have an adequate supply of fuel when the engine is cranked.

It is a further object of the invention to provide a control system and apparatus in which the closure of a normally open, manual switch serves to cause substantially immediate energization of an electric fuel pump and a delay device, said device-serving to energize the 2,949,906 Patented Aug. 23, 1960 taken substantially on the line 22 of Figure 4 showing the fuel pump switch and its actuating means.

Figure 3 is a sectional elevation of the switch apparatus taken substantially on the line 3-3 of Figure 4 showing the bimetal thermoswitch and its heating mechanism.

Figure 4 is a plan view of the apparatus of Figure 2 with the fluid pressure responsive device removed.

Figure 5 is a side elevation of the ground terminal.

Figure 6 is a chart showing a typical fluid pressuretime delay gap relation.

Wiring diagram 7. A Wire 9 connects the output side of this switch to the engine starting motor a short time after closure of the switch and starting of said pump.

Another object of the invention is to provide means responsive to engine lubricating oil pressure for holding said fuel pump energized after said manual switch is opened.

Yet another objectof the invention is to deenergize the starting motor as soon as the manual switch is opened.

A further object of the invention is to provide a compact unitary structure which includes the pump starting mechanism, the delay device and the oil pressure responsive means so as to simplify circuitry and reduce costs of manufacture and installation.

Still another object is to provide switching apparatus in which the switch contacts are constructed so as to provide wiping engagement to maintain them clean.

It is another object of the invention to provide simple and externally accessible means for adjusting the pressure responsive and time delay means to vary the pressure and time response thereof.

A further object of the invention is to provide a switch blade of the cantilever type which resists vibration and fracture in operation.

Still another object of the invention is to provide diaphragm support disc which cooperates with a dished pressure plate to reduce the effective area of the diaphragm as the oil pressure increases.

Still another object of the invention is to provide a diaphragm control disc which will prevent closure of the fuel pump switch'until a predetermined minimum oil pressure is attained.

Yet another object of the invention is to provide a solenoid mounting means and terminal posts which are of ferromagnetic material so as to provide a magnetic fl-ux path to the solenoid armature.

These and other objects will become apparent from a study of this specification and the drawings which are attached hereto, made a parthereof and in which:

Figure 1 is a diagrammatic view of the fuel and elec- 'trical systems.

Figure 2 is a sectional elevation of the switch apparatus ignition apparatus indicated generally by 11.

A wire 13 connects the output side of this switch to one fixed contact 15 of a normally open, manually closeable starting switch 17 which may be of any desired type. This switch is often incorporated in the ignition switch. The other fixed contact 19 of this switch is connected by wire 21 to a terminal post 23 of the control apparatus which is indicated generally by 25.

The control apparatus comprises three separate devices incorporated in a unitary structure. It includes a relay 27 which comprises a coil 29, a pair of normally open contacts 31 mounted on spring type switch blades 55 and 57, which are connected in electrical communication with terminal posts 59 and 61 respectively, and an armature 33; a thermal switch 35 which comprises a resistance heating coil 37, a bimetal blade element 39 mounted at one end on terminal post 23 and a pair of normally open contacts 41, one mounted on the bimetal element and one fixedly mounted on a terminal post 40; and a fluid pressure responsive device 43 which comprises a diaphragm 45 forming a wall of a pressure chamber 47 which has a tube 49 for connection with the pressure side of the oil pump 50 which is driven by the engine and a push rod 46 disposed for actuation by the diaphragm and for contact with switch blade 55 so as to urge the latter toward blade 57 to close switch 31 as the diaphragm expands under pressure.

A wire 51 connected to terminal 23 is connected to one end of relay coil 29 and to one end of heater coil 37 Terminal 23 is also connected to one end of the bimetal element 39. The other ends of the coils are connected to a terminal 165 which is grounded at 54.

One of the posts, here shown to be post 59 is connected by wire 63 to starter switch contact 15 or otherwise directly to the output of switch 7 while the other post 6-1 is connected by wire 65 to one side of the fuel pump motor 67 while the other side is grounded at 69.

A starting motor relay 71 comprises a coil 73, a pair of fixed contacts 75, a movable contact 77 adapted to bridge contacts 75, and an armature 79. Contacts 75 and 77 are normally open but are closed when the coil is energized so :as to attract the armature. A wire 81 connects one contact 75 to the battery ahead of the ignition switch and a wire 83 connects the other contact 75 to one side of the starting motor 85 while the other side of the motor is grounded at 87.

One side of the coil 73- is connected to the terminal post 40 by wire 89 while the other side is grounded at 91.

The fuel conduit 93ponnects the discharge of the fuel pump with the float chamber of the engine carburetor or other fuel charging device (not shown).

System operation While the detailed construction and operation of the control or switch apparatus 25 will be set forth below,

the general operation of the system and its components is as follows:

When it is desired to start the engine, the ignition switch 7 is closed to energize the ignition system and to connect starting switch contact 15 with the battery.

The starting switch 17 is then manually closed andheld closed to extend the battery current to terminal post 23, relay coil 29, heater coil 37 and bimetal ele ment 39. Relay 27 closes the switch 31 at once but clo-- sure of switch 41 occurs only after the heater coil has heated the bimetal element 39 enough to cause it to warp in the direction to close the switch.

Closure of the switch 31 therefore closes the circuit from the battery to the fuel pump motor 67 through lines 5, 13, 63 and 65 to ground and the fuel pump will start. This operation occurs before switch 41 closes to apply the starting motor load to the battery so that substantially the full battery voltage will be applied to the fuel pump motor 67.

This is an important feature of the system because in cold weather, the motor 67 and pump 95 usually require a substantial amount of current on the initial start because of increased frictional loads imposed by bearings etc. The voltage and efiiciency of the storage battery is usually reduced at low temperatures and if the heavy drain of the starting motor is imposed on the battery at a time when the fuel pump requires more than its usual starting current, the pump motor may not start and may thus contribute to a failure of the engine to start, if the fuel supply at the carburetor happens to be depleted.

The current requirements of the fuel pump, when it is running, are such that it is not likely to stall when the starting load is applied.

By energizing the fuel pump motor in advance of the starting moto'r, the operation of the fuel pump and an adequate supply of fuel at the carburetor will be assured under the most adverse temperature conditions, so that the starting of the engine will not be defeated for lack of fuel.

Heater coil 37, which was energized at the same time as relay coil 29, will heat the bimetal element 39 and cause it to Warp in a direction to close contacts 41. The time required to close these contacts will depend upon a number of factors such as the ambient temperature, the resistance of the heater coil, the normal spacing of the contacts 41, the state of the battery voltage etc. However, since this coil is operated prior to the starting motor, it will have the benefit of substantially full battery current in the same manner as the fuel pump. Accordingly, the time required for closing switch 41 can be regulated, for all practical purposes, by the gap between the contacts at a selected temperature, so that it will close within a few seconds and the other variable factors will not alter this period by more than approximately 50 percent.

When switch 41 closes, while the ignition and starting switches are both closed, it connects the battery through lines '5, 13, 21, post 23, bimetal element 39, switch 41, post 40, line 89, relay coil 73 to ground 91. The coil attracts armature 79, closes switch 75, 77 and establishes a circuit from the battery through lines 5, 81, switch 75, 77, line 83, starting motor 85 to ground 87. Motor 85 then cranks the engine.

When the engine starts, the starter switch. 17 is released, and opens contacts 15, 19 thus deenergizing the circuit through the relay coil 29, the heater coil 37, the bimetal element 39 and starter relay coil 73 so that as a result, fuel pump switch 31 is no longer held closed by relay coil 29. However, the engine oil pump 50 applies oil under pressure through tube 49 and chamber 47'to the diaphragm 45 which moves the push rod 46 and blade 55 in a direction to hold or to close switch 31, depending upon the value to which the oil pressure risesduring cranking and immediately upon starting.

If this switch is still held closed by the relay, the diaphragm will cause the blade 55 to follow blade 57 when the relay coil 29 is deenergized as explained above and the switch 31 will remain closed.

Should the switch 31 be opened due to the deenergization of coil 29 before the oil pressure has built up sufficiently to cause blade 55. to follow blade 57 as rapidly as the latter is withdrawn, it will eventually be reclosed when the proper oil pressure is reached. Thus, a proper supply of fuel will be provided at the engine so long, as the required oil pressure is maintained.

However, should the oil pressure fail to rise, or having risen, should thereafter. fall below the value required i to hold the switch 31 closed, the switch will of course sure responsive device 43 in a single structure.

open and stop the fuel pump. When the fuel supply at the engine becomes exhausted, the engine will stop.

Further should the engine stall for any reason while the ignition switch remains closed, the oil pressure will fail and the diaphragm 45 will yield to the diaphragm support disc 147 (described below) and permit switch 31 to open and stop the fuel pump. This prevents unnecessary drain on the battery, wear on the fuel pump and detrimental agitation and heating of the fuel in the tank.

Should the engine be stopped as the result of a collision: or other accident, the stopping of the fuel pump, as described above, will prevent fuel from being pumped into the engine compartment to create a fire hazard or to aggravate a fire which may have already started.

Switch apparatus The preferred form of my switch apparatus incorporates the relay 27, thermal switch 35 and the oil pres- It comprises a fitting 49 which is connected to a dome 91' which has a peripheral flange 93. A generally cylindricalbody 95 is preferably molded of plastic material of a thermosetting type, capable of withstanding the temperatures and other conditions encountered in an engine coinpartment.

A disc-like metal pressure plate 97 has its central portion dished downwardly toward a central, axial opening 99 and is surrounded by a flat peripheral flange 191 adapted to seat on the upper end of the body.

The diaphragm 45 is preferably formed out of sheet synthetic rubber material which has a bursting strength of several hundred pounds and does not deteriorate materially when exposed to hot lubricating oils such as are used in automobile engines; The diaphragm is disposed between the flanges 93 and 161 which are clamped in sealing relation against the diaphragm by a cover or ferrule 103. The ferrule is preferably generally cylindrical and has an internal diameter which fits slidingly over the top portion of the body 95. The ferrule has an inturned flange at its upper end which overlies the top of flange 93.

The lower portion of the body 95 has a reduced diameter 107 so that it forms a downwardly facing shoulder 109 over which the lower end of the ferrule is crimped' as at 111. The ferrule is subjected to axial pressure prior to crimping so that the ferrule will hold the diaphragm compressed between the flanges 93 and 101. Dome 9 1 and the diaphragm define an .oil pressure chamber 47.

A pair of diametrically opposed terminal posts 59, 61 are molded as inserts in the body 95 and extend from the bottom thereof to the switch chamber or cavity 117 thereof which has its upper end closed by the pressure plate. The body'alsodefines a solenoid chamber o'r cavity 119 which has its bottom end closed by a wall 121 but which communicates with the switch cavity;

The relayor-solenoid' assembly 27 comprises posts 59; 61,, core 125, a coil 29 fitted on the core, a coil back up. washer 127' of insulating material, solenoid support plate 129 which extends outwardly over the- posts 59, 61, and screws 131 and 137' which hold the plate on the posts 61 and 59. The pushrod 133, of nonmagnetic material, is slidably mounted in the core 125 and carries at its lower end a ferrous metal armature disc 33. One magnetic circuit is thus formed from plate 129 through post 61, across a gap to the armature 33, across a second gap to core 125, all of which are of ferromagnetic material, and back to the plate. A second flux circuit is established in a similar manner through post '59.

The switch 31 comprises upper and lower spring blades or leaves 55, 57 which are held in spaced, superposed relation by an insulating spacer 113. An insulating sleeve 115 is passed through a hole in the lower blade and through the spacer but terminates short of the upper blade. An insulating washer 135 is disposed between the solenoid plate 129 and the top of post 59 and the lower end of sleeve 115 passes through the washer. A screw 137 is passed through a hole in the upper blade 55, through sleeve 115 and is screwed into the upper end of post 59. Thus, it will be seen, a current path is formed from post 59 through screw 137, blade 55, contacts 31, blade 57, plate 129, screw 131 to post 61 whenever the cont-acts are closed. They are, of course, normally held open by the resilience of the blades '55 and 57.

It should also be noted that, as shown in Figure 4, the blade 55 is widest at the fixed end and tapers, preferably uniformly, toward the free end. The contact is mounted adjacent the free end. It has been found that such con struction insures against breakage of the blade at the edge of the spacer 113 and also renders the blade less responsive to vibration at the frequencies normally encountered in use, so that premature closure or chattering of the switch is minimized.

It will be seen that the pushrod 133 bears on the under side of blade 57 intermediate its ends and Will bend it upwardly when the solenoid coil 29 is energized. The stroke of the push rod is such as to force the contact 31, mounted on the free end of the blade, into pressure contact with the opposed contact on blade 55 and hold the blade 57 slightly bowed.

A pushrod or plunger 46 of insulating material such as vulcanized fiber is provided with a generally cylindrical head 139, a shank portion of lesser diameter than the head and a lower end portion of further reduced diameter so as to form, with the shank, a shoulder 141. The lower end of the plunger enters a hole 143 located intermediate "the ends of the blade 55 so that the shoulder will bear against the upper side of the blade. The plunger 46 and pushrod 133 are preferably disposed in a substantial axial alignment.

The head passes freely through the opening 99 in pressure plate 97 and is also provided with a threaded axial hole 145. A diaphragm support disc 147 which is cen trally perforated, is mounted on the head of the plunger by means of a shoulder screw 149 which enters the disc and is screwed into hole 145. It is preferably also cemented therein. A stop ring 151, described below, limits the downward travel of the plunger when it is forced into contact with plate 97 by the disc 147.

The support disc 147 is an important element because it controls the action of the switch, in both the opening and the closing directions, in response to the forces applied to the diaphragm by the oil pressure in chamber 47.

The disc has a diameter which is preferably about half that of the plate 97 and is normally held out of contact with the plate, as shown in Figure 2, by the resilience of blade 55, when there is no pressure in chamber 47. As pressure is applied to the diaphragm it will move disc 147 downwardly until its lower, peripheral edge engages the dished portion of the pressure plate 97. As increasing pressure is applied to the diaphragm, a portion of the diaphragm will be supported by the plate and the remainder by the support disc 147, so that the disc will have its central portion bowed or dished downwardly as the pressure increases. I

Assuming that the solenoid 27 is deeuergized, the construction of the pressure responsive device is preferably such that the diaphragm and disc will move from the normal position (Fig. 2) to the position in which the disc contacts the pressure plate, in response to a relatively small increase in pressure such as, for example, 3 p.s.i. and that this motion will close the major portion, for example, 80 to 90% of the gap between contacts 31.

It is further preferred to have the remaining portion of the gap close only at somewhat higher pressure such as, for example, 7 p.s.i. and that further movement of plunger after closing of the contacts be limited by the stop 151 to an amount suflicient to impart a slight downward bowing of said blade 55, sufficient to hold the contacts under pressure, regardless of the final oil pressure, which may reach 40 p.s.i or more.

The action of these parts in response to reduced pressure in the diaphragm chamber will, of course, be substantially the reverse of that described above and will produce a positive release of the blade 55 when the pressure drops below the contact closing pressure. It should be noted that the effective area of the diaphragm which is subjected to the pressure in chamber 47 is reduced to the equivalent of the area of the disc when the latter is in contact with the plate 97 and this, together with the resistance of the disc to fiexure increases the ratio of increase in pressure to contact movement as explained above. The change in effective area also reduces the total load applied to the stop 151 under the maximum oil pressure.

I have found that a disc made of glass cloth impregnated with silicone resin identified as GSG (Nema G-7) manufactured by the Taylor Fibre of Norristown, Pennsylvania, is satisfactory, not only because it provides the desired control but also because it is thermally stable, moisture proof and will withstand the relatively rigorous conditions to which it is subjected.

The general relation of increase in pressure to gap closure in the example given above, is shown by the graph (Figure 6). Variations in the initial size of the gap, the diameter of the disc and the dish contour of plate 9 will, of course, alter the points at which the curve changes direction but the characteristics of the curve will be the same.

It should be noted that since the pushrod 133 and plunger 46 act on the switch blades intermediate the ends thereof, the contacts will engage with a wiping action and will be kept clean thereby. If desired, an adjusting screw 153 may be mounted in a tapped hole disposed axially in the bottom wall 121 of the body so that it may limit the descent of the armature 33 and thus serves to adjust the magnetic gap between the armature and core 125 and also the gap between contacts 31. The size of the magnetic gap, in turn, varies the coil voltage to which the armature will respond.

Disposed loosely on the head of the plunger 46, below the diaphragm support disc, is the stop ring or washer 151 which limits the downward motion of the plunger when the stop ring is forced into contact with the plate 97 by the descending support disc 147. It thus limits the downward displacement of the plunger, just as the contact between the armature 33 and core 125 limits the upward movement of pushrod 133, so that the flexure of the switch blade 55 is limited to a predetermined maximum regardless of the pressure in chamber 47.

Referring now to Figures 3 and 4, it will be seen that two additional diametrically opposed binding posts 23 and 40 are also molded as inserts in the body 95. The post 23 extends upwardly into chamber 117 to a level above the switch blade 55.

A laminate comprising a bimetal blade 39, a top strip 155 of mica and a bottom strip 156 of the same material as disc 147 is wound with coil 37 of resistance wire. This laminate is mounted at one end on the post 23 by a screw 157 and a terminal 159 to which one end of the heater coil is connected.

A contact 41 is mounted on the free end of the bimetal blade and. the adjacent ends of the insulating strips are provided with v notches 161 which engage the contact to prevent pivotal movement of the mica and coil about screw 157. The free end of the bimetal blade is guided in a groove 158 formed in the case.

The lead from the opposite end of coil 37'runs' parallel to the laminations, is wound once or twice about tabs 163, which extend from strip 156 and is connected to a ground terminal 165 (Figs. 4 and 5). The terminal is mounted on the body by an upwardly extending leg 169 thereof which is provided with an offset end (Fig. 5), the horizontal portion 1'71 of which lies between the pressure plate 97 and the end of the case and the free end 173 of which extends upwardly between and in pressure contact with the edge of plate W and the interior of the ferrule 103. One end of the solenoid coil 29 is also connected to this terminal 165 while the other end thereof is connected to post 23.

The dome 91 and fitting 49 are connected with the body or engine of the vehicle and the terminal is thus connected to the ground of the battery. Thus the heater coil 37 and the relay or solenoid coil 29 are connected in parallel from post 23 through terminal 165 to ground 54.

It will be noted that the mica and bimetal element laminate is centrally perforated at 175 to pass, freely, shank of the plunger 46.

Post 4% is provided with an. internal. bore 177 having a threaded hole at the upper end. The fixed contact 41 has a reduced, threaded shank 179 surrounded by a spring 181 and is screwed into the hole. The shank is preferably provided with a screwdriver slot so that it can be readily adjusted from the exterior of the body through bore 177. Both this contact and adjusting screw 153 are preferably fixed, after adjustment, by applying a suitable plastic cement.

The contacts of switch 41 are preferably normally open under ambient temperatures but when the heater coil is energized and the bimetal strip warms, it will warp or how in a direction to urge the contacts 41 closed.

Operation As explained briefly under the operation of the system, current is first applied simultaneously to the solenoid coil 29 and the heater coil 37 from terminal post 23 to ground through terminal 165.

The coil 29 immediately draws armature 33 upwardly causing the pushrod 133 to force blade 57 upwardly to close contacts 31. The stroke of the pushrod is of sufiicient magnitude to bow the blade 57 slightly so that the contacts are in pressure engagement and engage with a slight wiping action. The closure of the contacts starts the fuel pump.

While the coil is held energized (by the starting switch 15, 17, 19), the heater coil warms the bimetal blade which warps and when it reaches a temperature of around 200 to 250 degrees F. (depending upon the setting of the gap of switch 41), the switch will close and energize the starter relay as described above.

Any increase in oil pressure due to cranking of the engine will urge the diaphragm 45 downwardly causing a like movement of disc 147, plunger 46 and switch blade 55. Since switch 31 is already closed the blades 55 and 57 will be further bowed.

As soon as the engine starts to run, the starting switch is usually opened. This will deenergize the coil 29 and the pushrod 133 will fall, relieving the pressure on blade 57. If the oil pressure of the engine rises rapidly to its maximum, the disc 147 may be bowed rapidly enough to hold the switch 311 closed. if the oil pressure does not rise quickly enough to maintain the switch 31 closed, it will-reclose the switch as soon as the pressure attains the required magnitude, so that the fuel pump operation is interrupted only momentarily.

When the oil pressure drops, for any reason, below that required to maintain the disc 147 fully distorted, the disc will start to open the switch. The opening of the switch to about 10 or 20% ofthe normal opening. will be acomplishedover an additional small drop in pressure of approximately two pounds per square inch. Since the solenoid coil 29 is not energized, this relatively small movement, which occurs rather rapidly, will effectively open the switch and deenergize the fuel pump motor. Assuming that the gap of switch 41 is set to close within two seconds at an ambient temperature of degrees F., if the ambient temperature is degrees F., the switch 41 will close in less than two seconds (about a half second less than at 70 degrees) because the heater and bimetal element will reach the 200 degree temperature more quickly. If the ambient temperature is low, say zero degrees F., the time required to close switch 41 would be more than two seconds (about 3 seconds). This is helpful because a longer time is needed, and is thus afforded, to start the pump and bring it up to speed before the starting load is thrown on the battery.

When the temperature in the engine compartment attains a normal level, which may be about 185 degrees F., the bimetal element will hold the contacts 41'closed or nearly closed, so that if the engine should stall in tralfic, it can be cranked without any noticeable delay.

Similarly, when successive crankings are required to start the engine, the bimtal does not return quickly to the position dictated by the ambient temperature because of the heat retained in the laminate, so that there is no material delay in the response of the cranking motor to the closure of the starting switch.

As noted above, the gap between the armature 133 and the core may be adjusted so that the armature will be pulled in at the minimum desired voltage. In a six volt system, the battery, when it is extremely cold, may produce only four volts in which case, to insure that the fuel pump and heater will be energized, the magnetic gap may be set so that the armature will pull in at 3.5 volts. Again the fuel pump and the solenoid will respond to even a weak voltage, before the engine starting motor is energized, to make certain that the fuel supply is available if and when the engine is cranked.

In any case, if the engine fails to start, the fuel pump will be deenergized substantially as soon as the starting switch is opened. If any oil pressure above that required to actuate the control disc has been built up by cranking, this pressure must be dissipated before the switch can reopen, but dissipation occurs rapidly upon stoppage of the engine, for any reason, from either cranking or running operation.

It is. obvious that various changes may be made in the form, structure and arrangement of parts of the specific embodiments of the invention disclosed herein for purposes of illustration, without departing from the spirit of the invention. Accordingly, applicant does not desire to be limited to such specific embodiments but desires protection falling fairly within the scope of the appended claims.

I claim:

1. An internal combustion engine control system in.-

, eluding an electric motor pump, an engine starting motor,

an engine starting switch and a source of electricity, means, including a normally open first switch, for connecting said electric motor pump to said source for energization thereby when said first switch is closed, means, including saidstarting switch and a normally open second switch, for connecting said starting motor with said source to energize said starting motor when said starting switch and said second switch are both closed, an energizable time delay mechanism for closing said second switch, means responsive to the closure of said starting switch for closing said first switch and for energizing said time delay mechanism, said last named mechanism serving to close said second switch only after said first switch has closed.

2. The structure defined by claim 1 wherein said second switch comprises a fixed contact and a movable contact and wherein said time delay mechanism comprises a heater connected to, be energized upon closing of said starting switch and a thermally responsive bimetal element, said element being constructed so as to warp in a direction to close said contacts when it is heated by said heater. I

3. The structure defined by claim 2 which includes means for connecting said movable contact with said source through said starting switch.

4. The structure defined by claim 1 wherein said means for closing said first switch includes a'solenoid having a magnet coil connected with said source through said starting switch and means, including an armature movable by said coil when the latter is energized, for actuating said first switch in direction to close it.

5. An internal combustion engine control system ineluding an electric motor pump, an engine starting motor, on engine starting switch and a source of electricity, means, including a normally open first switch for connecting said electric motor pump with said source for energization thereby when said first switch is closed, means, including said starting switch and a normally opensecond switch, for connecting said starting motor with said source to energize said starting motor when said starting switch and said second switch are both closed, an energizzable time delay mechanism for closing said second switch, means, responsive to the closure of said starting switch, for closing said first switch and for energizing said time delay mechanism, said last named mechanism serving to close said second switch only after said first switch has closed and means operable by said engine when it is running, for holding said first switch closed.

6. The structure defined by claim 5 wherein said second switch comprises a fixed contact and a movable contact and wherein said time delay mechanism comprises a heater connected to be energized upon closing of said starting switch and a thermally responsive bimetal element, said element being constructed so as to warp in a direction to close said contacts when it is heated by said heater.

7. The structure defined by claim 6 which includes means for connecting said movable contact with said source through said starting switch.

8. The structure defined by claim 5 wherein said means for closing said first switch includes a solenoid having a magnet coil connected with said source through said starting switch and means, including an armature movable by said coil when the latter is energized, for actuating said first switch in direction to close it.

9. The structure defined by claim 5 which includes an engine driven lubricating oil pump and wherein said means for holding said first switch closed comprises a fluid pressure responsive device having a pressure chamber connected in communication with the discharge side of said oil pump and having means, including an element movlable in response to the increase and decrease in pressure in said chamber, said element being disposed so as to urge said first switch closed in response to increasing pressure.

10. An internal combustion engine control system including an electric motor pump for supplying fuel to an engine, and engine starting motor, an engine starting switch and a source of electricity, means, including a normally open first switch, for connecting said electric motor pump to said source for energization thereby when said first switch is closed, a normally open second switch, a time delay mechanism comprising a heater and a thermally responsive bimetal element arranged to be heated thereby, said element being constructed so as to warp, when heated, so as to close said second switch, a relay adapted to be energized to close said first switch, means connecting said starting switch to supply current from said source to said heater, to said relay and to said second switch when said starting switch is closed and means connected to said second switch for supplying energy to said starting motor from said source, when said second switch and said starting switch are both closed.

11. The structure defined by claim 10 which includes an engine driven pump adapted to supply fluid under pressure thereto, a fluid pressure responsive device, connected for operation by fluid pressure from said pump, and arranged to urge said first switch closed in response to said fluid pressure, irrespective of the condition of said relay.

12. In a unitary switching apparatus, the combination of a body, a normally open first switch mounted on said body, a solenoid mounted on said body and including means for actuating said switch to close it when said solenoid is energized, a fluid pressure responsive device on said body and including means responsive to rising fluid pressure therein for actuating said switch in a closing direction, a normally open, thermally responsive, delayed action, second switch mounted on said body, adapted to close in response to heating, electric heating means for said second switch and means for connecting said solenoid and heating means for simultaneous energization.

13. The structure defined by claim 12 wherein said first switch comprises oppositely disposed, resilient blades provided with overlapping contacts, said solenoid and said fluid pressure responsive device being disposed on said body so as to actuate a different one of said blades.

14. The structure defined by claim 13 in which the spring blade disposed for operation by said fluid pressure responsive device is of a cantilever form and is convergingly tapered in width toward its free end.

15.. The structure defined by claim 12 wherein said fluid pressure responsive device comprises a dome, a diaphragm sealingly mounted thereon and defining therewith a fluid pressure chamber, a rigid plate disposed over the exterior of the diaphragm and centrally dished in a direction away from said diaphragm, said plate defining an axial opening, a plunger disposed for axial reciprocation in said opening, a disc of resilient flexible material mounted on said plunger, disposed between said diaphragm and plate, having a diameter substantially less than that of said plate and having a peripheral edge adapted to engage the dished portion of the plate, said plate and disc serving to limit both the free motion of said diaphragm in response to increasing pressure in said chamber and the effective area of said diaphragm which responds to increasing pressure in said chamber after engagement of said plate and disc, said disc serving to resist and control the movement of said plunger in response to further increase in said pressure and wherein said plunger is disposed to actuate said first switch in said closing direction.

16. The structure defined by claim 15 wherein said disc comprises a woven glass fiber cloth impregnated with a thermosetting silicone resin.

17. The structure defined by claim 12. wherein said body includes a terminal post, a solenoid plate mounted on said post, a solenoid core mounted on said plate, a coil mounted on the core, a pushrod of nonmagnetic material slidably mounted for reciprocation in the core and having an armature at one end, disposed in spaced relation with said post and normally spaced from said core, said post, solenoid plate, core and armature being of ferromagnetic material and forming a flux path interrupted by the gaps between the armature and said post and the armature and said core, so as to increase the force which attracts the armature to said core when said coil is energized, said first switch including a member disposed for actuation by said pushrod.

18. The structure defined by claim 17 which includes a second terminal post of ferromagnetic material arranged to form, with said plate, core and armature a second flux path and means for connecting each side of said first switch with one of said posts.

19. The structure defined by claim 12 which includes two terminal posts of electrically conductive material, mounted in said body in spaced relation from each other, said second normally open switch including a b-imetal blade mounted at one end on one post and having a first contact, a second contact mounted on the other post and disposed in spaced relation to but for engagement with said first contact, said bimetal blade being constructed so as to Warp, when heated, in a direction to close said contacts, and to establish a circuit through said posts and blade, a heater mounted on said blade, a ground terminal mounted on said body, means connecting one end of said solenoid and said heater with said one post and the other end of said solenoid and said heater with said ground terminal.

5 References Cited in the file of this patent v n.- T

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