US2084426A - Fuel cut-off - Google Patents

Description

R. G. BERRY June 235 FUEL CUT-OFF Filed Jan. 2, 1934 2 Sheets-5het 1 FlG.

RUSSELL G. BERRY INVENTOR A TTORNE Y June 22, 1937. R, G BERRY 2,084,426

FUEL CUT- OFF Filed Jan. 2, 1934 2 Sheets-Sheet 2 FIG.5

RUSSELL G. BERRY INVENTOR l #1 v I I ATTORNEY 15 idling passage to the engine.

Patented June 22, 1937 UNITED STATES PATENT OFFICE FUEL CUT-OFF Russell G. Berry, De Soto, Mo., assignor to Carter Carburetor Corporation, St. Louis, Mo., a

corporation of Delaware Application January 2, 1934, Serial No. 704,971

. 8 Claims.

The present invention appertains to improvements in carburetors for internal combustion engines and more particularly to means for con-- serving fuel, and preventing excessive dilution of v the crank case oil under certain conditions. This application is a continuation in part of applicants co-pending application No. 463,100, filed June 23rd, 1930.

When an automobile is coasting down hill or 10 coasting to a stop with the throttle closed and with the engine turning'over at a speed corresponding to the speed of the automobile, a comparatively high vacuum exists in the intake manifold and fuel is supplied through the conventional Since no power is required from the engine under these conditions, all of the fuel supplied is Wasted. These periods of coasting may be several miles in length as when coasting down a mountain with the engine in gear to act as a brake.

of coasting may be only a few feet in length as when coasting to a stop in city driving, or when momentarily slowing up the automobile. For long coasting periods of several miles in length the operator may turn off the flow of fuel to the carburetor but this is not entirely satisfactory because the float chamber of the carburetor contains a substantial quantity of fuel and this fuel would be used up before the'turning off of the flow of fuel to the carburetor had any effect. Obviously this method of turning off the fuel cannot be used in coasting to a stop because the gasoline control valve in the line leading to the carburetor is usually under the hood and the operator would have to get out of the car to operate it.

Another difficulty with previous carburetor constructions is what is known as percolation. Gasoline is composed of varous hydrocarbons which boil anywhere from 106 degrees Fahren- 40 heit to 450 degrees Fahrenheit: The temperature existing under the hood of an engine may be 200 degrees Fahrenheit or even more. The result is thatboiling occurs in the carburetor and particularly in the upwardly directed passageways which lead to the discharge outlet of the nozzle. The

carburetor is, of course, connected to the engine On the other hand the periods is emptied. It will be understood, of course, that this condition is most serious after the motor has been thoroughly heated up by running and then brought to a stop. During the normal running of the automobile or internal combustion engine, 5 there is usually sufficient gasoline flowing thru the passages leading to the nozzle of the carburetor to cool the metal surrounding the passages and prevent the boiling or percolation.

A third difliculty with certain types of internal l0 combustion engines is that the operator may forget to turn on the switch or ignition prior topperating the self starter or cranking the engine. In such cases the engine may frequently become so flooded with gasoline that it will fail to start and 15 continued cranking only aggravates the difliculty.

. whenever the ignition switch of the engine is 5 turned off.

A further object of my invention is to provide an additional switch which is more conveniently operated than even the ignition switch so that the operator can instantaneously cause the closing of 3p, the gasoline control valve at any time without taking his hand from the steering wheel.

Other important objects and advantages of the invention will readily become apparent to the reader during the reading of the following speci- 35 fication and claims.

In'the drawings: v

Figure 1 represents a diagrammatic view disclosing the electrical connections by means 'of which the device is operated. 40

Figure 2 represents a diagrammatic sectional view disclosing a simple form of carburetor with the electromagnetic valve mounted thereon.

Figure 3 represents a horizontal sectional view taken substantially on the line 33 of Figure 2. 45

. Figure 4 is a vertical'sectional detail view of the switch means.

Figure 5 is a diagrammatic vertical sectional view showing an improved form of my device.

Referring to the modification shown in Figures 1 to 4 of the drawings, it can be seen that numeral 5 in Figure 1, refers to the usual storage battery found on an automobile. l The lead 6 extends from the battery and to the ammeter 1,

from whicha wire 8 extends to one side of the ignition switch 9. One wire l extends from the other side of the ignition switch 9 to the usual spark coil I I. A second wire l2 extends from the ignition switch 9 to a switch unit generallyreferred to by numeral I3.

A wire I4 extends from the switch unit l3 into the electro-magnetic valve generally referred to by numeral I5, one side of which is grounded by the wire IS.

The switch generallyreferred to by numeral.

l3 includes a cover H, the bottom of which is 1 formed as a casing -,l8. The bottom of this casing I8 is normally closed by the plate IS. A

plate 20 formed of insulating material is secured to the under side of the floor plate I] and carries a pair of stationary contacts 2l- 2I, to one of which the wire I2 is secured and to the other the magnetic valve 34.

wire I4 is secured.

A tubular riser 22 is provided on the plate i1 and as clearly shown in Figure 4, a rod 23 is slidable through this riser 22 and through an opening in the cover II, to connect to the switch blade 24, located within the casing l3.

. A cap 25 is secured to the upper endof the rod 23, and is mounted to telescope the upper end of the riser 22. A coiled spring 26 is interposed between the plate H and'the cap 25 for normally maintaining the cap 25 raised with the blade 24 bridging the contacts 2I--2-l.

The wires I2 and I4 are trained through an opening in the side of the casing l3.

As before stated, numeral I generally refers to the electro-magnetic valve which is located within the carburetor generally referred to by numeral 21. I

The carburetor is provided with a carbureting chamber or mixing conduit 30 and the conventional float chamber or constant level chamber 40 in which the fuel is maintained at a substantially constant level indicated by the broken line AA' by a. conventional float 4| which controls the usual fuel inlet needle valve '42. It will be understood that fuel is supplied to'the inlet passage 43 of the float chamber by any suitable means, many devices for this purpose being well known to the art. I

A conventional main nozzle 29 and idling tube 28 are provided, and these are connected with they float chamber by means of the passage 3|,

the inlet of which is controlled by the electro- A valve seat or bushing member 32 is preferably. threaded into the inlet end of'the conduit 3| for the purpose of conveniently forming a seat for the valve 34.

The electro-magnetic valve includes the; coil 33, suitably secured to the carburetor shell. The

valve element 34 is secured to the armature plate 35 and the guide stem 36 protrudes into the core of the magnet to guide the valve when in its normal elevated position.

It can now be seen that when the automobile is moving down-grade, the operator may depress the button-23m break the connection between the switc .9 which results in the de-energization of the magnet 33 and the closing of thevalve fl 50 that there is no chance of boiling any more fuel out of the carburetor than is contained in the passages 3!, 28 and 29. In fact the closing of the valve 34 usually prevents the loss of any fuel from either the nozzle 29 or the passageway 23.

In case the operator should start to crank the automobile without remembering to turn on the switch 9, there is no danger of flooding the engine with gasoline because the valve 34 remains closed until after the ignition is turned on by means of the switch 9.

\ Referring to the modification shown inFigure 5, the chief difference in principle between this construction and that previously described is that an automatic arrangement is provided for cut-' The switch is so constructed as to be operated I by the extremely high suction which is developed when the engine is running at faster than idling speed with the throttle closed. This suction condition in four cycle motors is well known to those skilled in the art but it may be briefly described as follows. Whenever the engine is running at full power or with the throttle .wide openthe highest suction that can be developed in the average intake manifold is not more than two or three pounds per square inch. If the throttle is gradually closed with the engine in operation the suction in the intake manifold, that isbetween the throttle and the engine, will gradually increase. If the engine is running at high speed as it would going down hill, under certain conditions, a suction of about ten or eleven pounds below atmospheric pressure is developed in the intake mani-' fold.

Under these conditions there can be no advantage in supplying any fuel to the engine because no power is required from it. On the other hand, power is being applied to the engine from the rear wheels ofthe car to maintain the high speed and the engine is acting as a brake on the wheels. If the car ceases to go down hill, the speed will be reduced and the suction in the intake manifold will also be reduced.

The normal idling speed of the motor is in the neighborhood of two or three hundred revolutions per minute and at this speed the pressure in the intake manifold will be in'the order of eight pounds below atmospheric. When the engine is running at this speed, fuel must be supplied to it or it would stop. The function of the switch 53 is to cause the supply of fuel to the engine to becut .oif whenever the suction in the intake manifoldsis substantially in excess'of the normal idling; suction.

While certain specific figures in .relation to the amount. of suction developed have been used, thue are merely illustrative. The normal idling suction of an engine depends to a great an existence of at least some difference between the suction developed in the intake manifold at ordinary idling speeds and the suction developed thereinat higher speeds when the throttle is closed. I,

In the construction shown in Figure 5, the

. switch 50 replaces the switch generally indicated reference numeral 52 indicates the main body of a carburetor of well known downdraft construction. This carburetor is provided with a constant level chamber 40 in which the fuel is maintained substantially at the constant level AA by the float mechanism generally indicated at 4|, the details of which are well known and need no further description. The throttle valve is indicated by the reference numeral 53 and is mounted on shaft 54 which operates the lever 55. This lever operates the metering valve 56 by means of a link 51 which is connected to the rocker arm 58, the rocker arm being pivotally mounted as indicated at 59.

The metering rod 56 extends into and through the main jet 60, the central'part of which is provided with a calibrated restriction 99, and

, the upper end of which is provided with the valve seat 6|. A tubular valve 62 loosely surrounds the metering rod. This valve is made of soft iron or other suitable magnetic material' and forms a slidable core forthe solenoid. The lower end of the tubular valve member 62 cooperates with the valve seat 6| to cut off the supply of fuel to the main nozzle 63 and idle passages when the supply of current to 'the solenoid 65 is cut off. The idle passage terminates in the idle port 88. A spring 68 may be provided if desired to assist in holding the valve 62 firmly on it's seat;

The switch casing 50 is provided with a flexible contactmember 61 which is perforated at 68 to prevent the sticking of the member 61 in position to close the end of the passageway 69, or in other words in position to break the circuit and cause the closing of the valve 62. The

passageway 69 is formed at its upper end of the valve seat to receive the member 61 of the valve and a restricted passageway 10 is formed in the passage 69 for the purpose of limiting the amount of air which may be admitted to the intake manifold when the member 61 is not in contact with the end of the passage 69. It will be understood that the casing 50 is vented as indicated at H. The casing 50 is insulated from the engine by means of insulating gaskets l2 and I3.

'I'he wiring connections for Figure 5 differ only slightly from the diagram shown in Figure 1. Like reference numerals 5, 6, 1, 8 and 9 refer to. the same elements which are used both Figures 1 and 5. Instead of .placing the automatic switch member between the manual switch 9 and the electrically operated valve, the ar-- circuit thru the member GT and the intake mani fold 5| tothe engine.

In operation the device is so adjusted as to preventoperation of the member 61 by normal idling suction or any suction below that. When ever the normal idling suction is substantially exceede as when the vehicle is coasting in gear, the su tion draws the member 61 against the endof the passageway breaking the contact 6| and cut off the supply of fuel to both the main and idling nozzles. The device operates on coasting down hills and even on coasting a few feet to a stop.sign. While the amount of fuel supplied under idling conditions is comparatively small, the use of this device will normally result in a saving of substantially five percent of the total amount of fuel used,- at least during city driving. Inhilly and mountainous country the saving will be substantially in excess of that.

A substantial advantage of this device relates to the fact that in coasting down long hills and going down mountains, the engine is generally used as a brake. With the throttle in the normal idling position, the engine, without this device, is supplied with a very lean, slow burning mixture which has a very substantial heating effect. This heating tends to keep the oil on the cylinder walls in a very thin and fluid condition, minimizing the braking effect of the engine. By the useof thisdevice the explosions in the cylinders are eliminated altogether during the coasting period, with the. result that the oil is.much more rapidly cooled and the braking effect of the engine is greatly improved.

The invention is not limited to thestructure as shown but may be modified in various respects as will occur to those skilled in the art, and the exclusive use of all such modifications as come within the scope of the appended claims is contemplated.

I claim:

1. In an internal combustion engine, an tion circuit having a control switch therefor, a carburetor having a fuel supply chamber, a a

carbureting chamber, and a fuel passage conout cutting off said ignition circuit.

2. In a device of the class described, a carbuigniretor, said carburetor having a constant level fuel chamber, a mixing conduit, and fuel passages leading from said constant level fuel chamber to said mixing conduit, means for cutting ofi the supply of fuel thru said passages. when the carburetor is'not in operation, and means for cutting off the supply of fuel thru said passages when the suction applied to said carburetor exceeds the normal idling suction.

3. In a carburetor, a constant level chamber, a main jet for conveying fuel from said chamber, a metering rod controlling said main jet, and a tubular valve surrounding said metering rod and movable therealong to seat against the upper end of the said main jet to cut' off the flow of fuel therethrough.

4. In a device of the class described, a carbureting chamber, a main fuel supply orifice therefor, a metering rod-extending through and 6 controlling said orifice, and a valve surrounding said metering rod and movable therealong to seat against the edge portion of said orifice and cut ofi the flow of fuel therethrough.

5. Structure as specified in claim 4-further including means responsive to the inoperative 7 condition of the device for moving said valve to' cut off said orifice.

6. Structure as specified in claim 4 in which ing means for moving said valve to cut off said orifice when the associated vehicle iscoasting 5 in gear.

7. In a device of the class described, a fuel mixture conduit, a passagefor supplyingiuel to said conduit, means for cutting off the supply I of fuel through said passage when the device is 10 inoperative, and means for cutting oi! said passage when the suction in said conduit exceeds normal idling suction.

8. In a device of the class described, a carbuv retor mixture conduit, apassage-for supplying fuel to said conduit, means for cutting oif said passage when the device is inoperative, and

means for cutting off said passage when the associated engine is being driven by a. force otherthan combustion in its firing chambers. v

RUSSELL G. BERRY.

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