US2969785A - Choke system - Google Patents

Description

Jan. 31, 1961 M. E- FUCHS ET AL 2,969,785

CHOKE SYSTEM Filed Jan. 5, 1959 v 4 Sheets-Sheet 1 FIG. l3.

FIG. I.

i I i i 1 J IL I J l H (1 I /i 5 \g it E 116, a 2i -433 k L 1| I45 INVENTORS, MARTIN E. FUCHS Y HARRY J. HERTLING ATTORNEY Jan. 31, 1961 M. E. FUCHS ETAL 2,969,785

CHOKE SYSTEM Filed Jan. 5, 1959 4 Sheets-Sheet 2 FIGZ. (II H as 1 81 23 a b 9 0 o o M Q I, 5

33 I 95 4 o I 1. a O o FIGS.

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II wiul l/2'7 I l I I STARTER T E 9 F129 TO IGNITION cz I35 //3\ x29 IN VEN TORS MARTIN E. FUCHS HARRY J. HERTLING ATTORNEY Jan. 31, 1961 Filed Jan. 5, 1959 FIG6. 3%?

M. E. FUCHS ET AL CHOKE SYSTEM 4 Sheets-Sheet 3 {um EB 61 3 f INVENTORS MARTIN E. FUCHS 55 HARRY J. HERTLING 35 BY ATTORNEY Jan. 31, 1961 E. FUCHS ET AL 2,969,785

CHOKE SYSTEM 4 Sheets-Sheet 4 Filed Jan. 5, 1959 FIGIO.

INVENTORS i MARTIN E.FUCHS 1:1 1 BY HARRY J. HERTLING ATTORNEY CHOKE SYSTEM Martin E. Fuchs and Harry J. Hertling, St. Louis, Mo., assignors to ACE Industries, Incorporated, New York, N.Y., a corporation of New Jersey Filed Jan. 5, 1959, Ser. No. 784,972

3 Claims. (Cl. 123-179) This invention relates to choke systems for internal combustion engines, and more particularly to an electrical choke system for the engine of an outboard motor.

Some outboard engines are provided with an electric motor for starting the engine, this motor being connected in a circuit including a starter switch which may be combined with an ignition switch in a key-operated unit, as in automotive practice, such that the key may be turned from OE position to Start position to close both switches for starting and, after the engine has been started, returned to On position to open the starter circuit While maintaining the ignition circuit closed. Such outboard engines have one or more carburetors, each provided with a choke valve. It is desirable that the choke valves of all the carburetors be fully closed when, with the engine cold, the starter switch is closed to start the engine, and, once the engine has been started, that they be partly opened and maintained in partly opened position until the engine has reached a predetermined operating temperature, and then that they be fully opened.

Accordingly, it is an object of this invention to provide a choke system for such an engine adapted automatically to accomplish closing of the choke valves of the carburetors when, with the engine cold, the starter switch is closed to start the engine, then to accomplish partial opening of the choke valves when the starter switch is opened once the engine has started, and then to accomplish full opening of the choke valves when the engine has warmed up, which system is of simple and economical construction and reliable in operation.

If the engine is warm but below the predetermined operating temperature when the starter switch is closed, it is desirable that the choke valves be partly opened and maintained in partly open position until the engine reaches the predetermined operating temperature. If the engine should be above the predetermined operating temperature when the starter switch is closed, it is desirable that the choke valves be fully open.

Accordingly, it is a further object of this invention to provide a choke system adapted automatically to accomplish partial closing of the choke valves when, with the engine warm but not up to the predetermined operating temperature, the starter switch is closed to start the engine, and to maintain the choke valves fully open when, with the engine at the predetermined operating temperature, the starter switch is closed to start the engine.

It will be understood that the invention is not limited in application to an outboard motor, being also useful, for example, in conjunction with an internal combustion engine for driving a generator in an electric generating plant of a type wherein the engine has a starting motor and a circuit for the starting motor including a starter switch which is actuated whenever there is a demand for power.

In general, a system of this invention comprises an 2,969,785 Patented Jan. 31, 1961 electrically actuated or electromagnetic means, such asa solenoid, for controlling the choke valve of the carburetor, or, where the engine has more than one car buretor, for controlling the choke valves of all the carburetors. The choke valve is biased to open. The sole noid or the like is adapted when energized to move the choke valve in closing direction. A first circuit including the starter switch and a first engine temperature responsive switch is provided which, when both these switches are closed, is adapted to establish suiticient voltage across the solenoid or the like to hold the choke valve fully closed against the opening bias. A second circuit including a second engine temperature responsive switch is provided for establishing a lower voltage across the solenoid or the like sufiicient to hold the choke valve only partly closed against the opening bias. The temperature responsive switches are both normally closed, the second being adapted to open at a temperature related to the predetermined engine operating temperature, and the first being adapted to open at a lower temperature. With this arrangement, when the engine is cold and the starter switch is closed to start the engine, the higher voltage is applied to the solenoid to close the choke valve. As soon as the starter switch opens, the lower voltage is applied to the solenoid so that the choke is partly but not fully opened. Then when the engine warms up to the predetermined operating temperature, the second temperature responsive switch opens and the choke valve fully opens. If the engine should be warm but below the predetermined operating temperature, the first temperature responsive switch will be open and the second closed. Accordingly, when the starter switch is closed, the lower voltage is applied so that the choke is partly opened. It the engine should be at or above the predetermined operating temperature, both temperature responsive switches will be open and, when the starter switch is closed, the choke will remain fully open.

Another object of the invention is the provision of an arrangement whereby, it the engine should not start withing a reasonable time, the choke is fully opened for unloading purposes.

This is expeditiously accomplished by making the first temperature responsive switch a time delay switch, which, for example, is self-heating on flow of current therethrough, and adapted to open in response to flow of current through the first circuit for a prolonged period of time so as to accomplish opening of the choke for unloading purposes if the engine should fail to start.

Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the constructions hereinafter described, the scope of the invention being indicated in the following claims.

In the accompanying drawings, in which several of various possible embodiments of the invention are illustrated:

Fig. 1 is a perspective view of an outboard motor to which a choke system of this inventionis applied, the shroud for the engine of the outboard motor being removed;

Fig. 2 is a perspective view of the upper end of the outboard motor as viewed from a difierent angle than in Fig. 1, on a larger scale than Fig. 1, with parts broken away and shown in section, and showing the carburetors on the engine;

Fig. 3 is a wiring diagram;

Fig. 4 is a view in elevation of a switch unit of the choke system;

Fig. 5 is a side elevation of Fig. 4;

Fig. 6 is a plan view of one of the carburetors on the engine;

Fig. 7 is an end view of the carburetors as viewed from the right of Fig. 6;

Fig. 8 is a vertical section taken on line 8-8 of Fig. 6;

Fig. 9 is a vertical section taken on line 99 of Fig. 6;

Fig. 10 is a vertical section taken on line 1010 of Fig. 6;

Fig. 11 is an end view of the carburetor as viewed from the left of Fig. 6, with parts broken away and shown in section;

Fig. 12 is a detail section of the carburetor; and,

Fig. 13 is a view similar to Fig. 5, on a reduced scale, illustrating a modification of the switch unit.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Referring to Figs. 1 and 2 of the drawings, there is 'indicated at 1 an outboard motor. The shroud of the outboard motor is shown as removed so that the engine 3 is visible. As herein illustrated, this engine 3 is a three cylinder engine, and three carburetors 5, 7 and 9 are provided on the engine, one for each cylinder. A starting motor for the engine is indicated at 11. A generator driven by the engine is indicated at 13.

Carburetors 5, 7 and 9 are .horizontal or side carburetors, arranged one above another. They are identical and a description of one will suifice for all. Each of the carburetors (see Figs. 6l2) comprises a body 15 formed to provide a horizontal mixture conduit 17. This is open at both ends. It has a restriction 19 (see Fig. 8) intermediate its ends so that it constitutes a venturi. At the outlet end of the mixture conduit, the body 15 has a flange 21 for attachment of the carburetor to the engine. A throttle shaft 23 extends vertically across the mixture conduit adjacent its outlet end and carries a throttle valve 25. A choke shaft 27 extends horizontally across the mixture conduit adjacent its inlet end and carries a choke valve 29.

Extending down from the body 15 is a tubular stem 31. A fuel bowl 33 has its bottom 35 engaging the lower end of the stem 31 and its rim engaging the bottom of the body 15. A screw 37 extends through a hole 39 in the bottom 35 of the bowl and is threaded in the lower end of the stem 31 to hold the bowl in place. The body 15 is formed with a fuel inlet 41 for receiving fuel from a supply. Extending down into the bowl from the inner end of this inlet is a needle valve 43 controlled by float 45 on a float arm 47 pivoted at 49. Float 45 is of annular form surrounding stem 31. The arrangement is :such as to maintain a substantially constant predetermined level of fuel in the bowl. A bowl vent isindicated at 51.

A main fuel nozzle 53 has its lower end 55 threaded in the stem 31. The upper end of this nozzle projects upward into the mixture conduit 17. Nozzle 53 has an external flange 57 engaging a shoulder 59 at the upper end of the stem 31. From its lower end 55 to the flange 57, the nozzle is of smaller external diameter than the internal diameter of the stem so as to provide an annular space 61 around the nozzle. This space is in communication with the outside atmosphere via a passage 63 (see Fig. 9). The nozzle 53 has a plurality of perforations therein such as indicated at 65. Fuelis adapted to enter the stem 31 above the screw 37 and below the lower-end of the nozzle through a port 67 under control of an adjustable needle valve 69.

An idle tube 71 has an enlarged upper end 73 fixed in a hole 75 in the top of the body 15 and extends down across the mixture conduit 17 and down through the nozzle 53 concentrically within the latter. Body 15 is formed to provide an idle passage 77 vfromhole 75 to an idle port 79 v(see Fig. 12) opening into themixture conduit 17. An idle adjusting screw is indicated at .81.

A throttle arm *83 is secured on the throttle shaft 23 at its upper end. A spring for biasing the throttle valve 25 closed is indicated at 85. An arm 87 is fixed on one end of the choke shaft 27. A'spring for biasing the choke valve 29 open is indicated at 89.

In accordance with this invention, and as illustrated in Fig. 1, the choke shaft arms 87 of the three carburetors 5, 7 and 9 are linked together by a vertically extending link 91. A solenoid 93 is mounted in vertical position on the engine 3 adjacent the link. The solenoid has a plunger 95 which has its lower end connected as indicated at 97 to a lever 99 pivoted at 101 on the engine 3 having a connection as indicated at 103 with the link 91. The arrangement is such that .when the solenoid is deenergized, the choke springs 89 of the three carburetors hold the choke valves of all three carburetors in their fully open position (horizontal) with the lever 99 and the plunger in a lowered retracted position. When the sole noid is energized, the plunger moves upward to swing the lever 99 upward and drive the link 91 upward ,to move the choke valves in closingdirection. How far the choke valves are moved depends on the voltage applied to ,the solenoid in relation to the closing bias of the choke springs; the higher the voltage, the more the choke ,valves move.

Referring now to Fig. '3, the system is shown to comprise afirst circuit C1 including a starter switch 105 and afirst engine temperature responsive switch 107 for establishing suflicient'voltage across the solenoid 93 to hold the chokevalves 29 fully closed against the opening-bias of springs 89. This first circuit includes a line 109 connected to one terminalof a battery B extending to the starter switch 105 (the other terminal of the battery being connected to ground as indicated at 111), and a line 113 extending from the starter switch to 107, with a line 115 extending from switch 107 to one terminal of the solenoid, and a line 117 extending from the other terminal of the solenoid to ground. Starter motor 11 is connected in a line 119 extending from line 113 to ground. The system also comprises a second circuit C2 including an ignition switch 121, 'a resistor 123, and a second engine temperature responsive switch for establishing a lower voltage across the solenoid sufficient to 'hold the choke valves 29 only partly closed (partly open) against the opening bias of springs 89. This second circuit C2 includes a line 127 extending from line '109 to the ignition switch 121,-a line 129 extending from the ignition switch to the resistor 123, and a line 131 extending from the resistor to the switch 125, and is completed-by lines 115 and 117. Line 115 is connected to a conductor 133 which connects switches 107 and 125. The ignition circuit is indicated at 135 extending from line 129.

The temperature responsive switches 107 and .125 are combined in a-unit shown in Figs. 1, 3, 4 and 5 and designated in :its entirety by the reference character 137. This .unit comprises a rectangular insulation base 139. A pair ofterminal screws 141 and 143 are threaded in the base at one .end thereof, these screws being located sideeby-side. Screw 141 is a terminal of .the first switch .107. Screw 2143 is a terminal of the second switch 125. At its other end, the-baseis formed with a ledge 145. A pair elf-electrically conductive leaf springs 147 and 1-49.extend from-the ledge over the screws. Each ofthese springscarriesacontact such as indicated at 151 at its freeend engageable with a contact ,153 on the end of the respective screw. The leaf springs are clamped on the ledgeby means of a .conductivebar which constitutes the previously mentioned-conductor 133, this bar 133 being secured to the base-by a bolt .155 which constitutes a common terminal for the two switches.

Switch-107,comprises the leaf spring .147 and a therrnostatic.blade*157 underlying this leaf spring foractuating it. Switch 125 comprises the leaf spring 149 and a thermostatic blade 159 underlying this leaf spring for actuating it. Each thermostatic blade has one end fixed on a spacer block 161 by means of a bolt 163 and a finger 165 at its other and free end engaging the respective leaf spring. Blades 157 and 159 are arranged to bend away from the base 139 on heating to bend the leaf springs 147 and 149 outward away from the base and disengage the contacts 151 on the leaf springs from the contacts 153 on the terminal screws 141 and 143. Blade 157 of switch 107 is adapted to open leaf spring 147 of switch 107 at a lower temperature than that at which blade 159 of switch 125 is adapted to open leaf spring 149 of switch 125. The switch unit 137 is mounted on the exhaust manifold of the engine 3 in a position such as illustrated in Fig. 1. Line 113 is connected to screw 141. Line 131 is connected to screw 143. Line 115 is connected to bolt 155.

Operation is as follows:

Battery B may be a twelve volt battery, for example. Thermostatic blade 157 of switch 107 may be selected so that switch 107 opens at about 90 F., for example. Thermostatic blade 159 of switch 125 may be selected so that switch 125 opens at about 105 F., for example. Accordingly, when the engine temperature is relatively low so that switch 107 is below 90 F., and the starter switch 105 and ignition switch 121 are closed to start the engine, approximately twelve volts is applied to the solenoid 93 via circuit C1, and this is suflicient to move the choke valves 29 of all three carburetors 5, 7 and 9 to their fully closed position against the opening bias of the choke springs 89. In this respect, it will be observed that with switches 105 and 107 closed, circuit C1 shunts the resistor 123 to apply full voltage to the solenoid.

As soon as the engine has started, the starter switch 105 is opened, but the ignition switch 121 remains closed. Accordingly, current is supplied to the solenoid 93 from the battery B through the circuit C2 including resistor 123 and switch 125. The resistor 123 drops the voltage to a value less than the twelve volts of the battery voltage, for example to six volts. With six volts applied to the solenoid 93, the solenoid is actuated only partly to close the choke valves 29 of the three carburetors 5, 7 and 9, closing these valves about halfway against the opening bias of the choke springs 89. The choke valves remain in this half closed (half opened) position until the engine temperature has increased to the point where switch 125 reaches its 105 F. opening temperature. Thereupon the switch 125 opens to deenergize the solenoid 93, and the choke valves 29 are then swung to their fully open position by the choke springs 89.

If the engine should be at such a temperature when the starter switch 105 is closed that the switch unit 137 is at a temperature between 90 F. and 105 F., meaning that switch 107 is open and switch 125 is closed, then when the starter switch 105 is closed, six volts will be applied to the solenoid 93 via circuit C2. This will result in partial closing of the choke valves on starting instead of full closing of the choke valves as occurs in starting the engine cold. As above, when the engine warms up, switch 125 opens to deenergize the solenoid, and the choke valves 29 will then swing from their partly opened position to their fully open position under the bias of the choke springs 89. If the engine should be at a temperature such that the switch unit 137 is at a temperature over 105 F. when the starter switch 105 is closed, both switches 107 and 125 will be open, and closing the starter switch 105 will not result in any operation of the solenoid. Accordingly, under these conditions, starting is efiected with the choke valves fully opened.

thermostatic blade 157a for switch 107 and clamping its end on ledge 145 under an electrically conductive memher 171 for connecting the blade 157a in shunt around the leaf spring 147 so that it carries current when the leaf spring 147 is closed. Then, when starter switch is closed, blade 157a is self-heated, this heating being relatively slow. If the engine starts quickly, the operation is the same as previously described. If the engine should not start within the prolonged time (five to ten seconds, for example) it takes the blade 157a to heat up to the point where it opens the leaf spring 147, then, even though the engine is cold, switch 107 opens so that the choke valves 29 are opened by the springs 89.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. In a fuel system for an internal combustion engine, a carburetor having a mixture conduit, a choke valve in said conduit, means biasing said choke valve to its open position, a solenoid operable to move said choke valve toward its closed position, a source of current, a first electrical circuit leading from said source of current to said solenoid, an engine starter switch and a first engine temperature responsive switch in said first circuit operable to energize said solenoid to move said choke valve to its closed position, a second electrical circuit leading from said source of current to said solenoid, an engine ignition switch, an electrical resistance coil, and a second engine temperature responsive switch in said second circuit operable to energize said solenoid to move said choke valve to its partly closed position, said first and second temperature responsive switches being initially in closed position, and each being movable to its open position responsive to an increase in temperature, said first temperature responsive switch being operable at a relatively lower temperature than said second switch.

2. A fuel system according to claim 1 wherein each of said temperature responsive switches comprises a contact carrying spring member, and a thermostatic element to actuate said spring member.

3. A fuel system according to claim 2 wherein the thermostatic element of said first temperature responsive switch is connected in said first circuit to be heated by current passing therethrough.

Sisson June 6, 1933 Hunt May 16, 1939

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