US2993484A

US2993484A - Deceleration fuel cutoff control for internal combustion engines

Info

Publication number: US2993484A
Authority: US
Inventors: Gallman Otice
Original assignee: JAMES G LEE
Current assignee: JAMES G LEE
Priority date: 1959-06-30
Filing date: 1959-06-30
Publication date: 1961-07-25
Anticipated expiration: 1978-07-25

Description

July 25, 1961 o. GALLMAN 2,993,484

DECELERATION FUEL CUTOFF CONTROL FOR INTERNAL COMBUSTION ENGINES Filed June 50, 1959 :6 y lo a? l I M! i\ 23 1 36 I 43 47 i S U W 1 45 22 I8 4| 4o 39 i 37 25 27 2e A i 28 v 46 3O 32 INVENTOR.

OTICE GALLMAN ATTORNEYS United States Patent 2,993,484 DECELERATION FUEL CUTOFF CONTROL FOR INTERNAL COMBUSTION ENGINES 0tice Gallman, 11266 Malat Road, Culver City, Calif asslgnor of one-half to James G. Lee, Culver City,

California Filed June 30, 1959, Ser. No. 823,981 SCIaims. (Cl. 123-97) This invention relates generally to internal combustion engines and more particularly to an improved engine control device for automatically shutting oif the flow of fuel to the intake manifold in response to deceleration of the engine.

It is well known that during deceleration periods of conventional automobile engines, relatively large portions of unburned fuel pass through the engine. The hydrocarbons present in this unburned fuel and emitted from the exhaust include a large percentage of ingredients believed to be the primary cause of smog or air pollution. In an eifort to remedy this situation, afterburners and the like have been proposed for effecting complete combustion of exhaust gases but these devices have thus far not proven to be satisfactory.

Aside from the problem of air pollution, unburned fuel passing through the engine during deceleration periods is not only wasted but can result in mufiler damage from backfiring.

With the foregoing in mind, it is a primary object of the present invention to provide an auxiliary control device for cutting off the fuel passed to the intake manifold of the automobile engine during deceleration periods to the end that no unburned fuel or any fuel for that matter is passed from the exhaust during such deceleration periods. As a consequence, all three problems of air pollution, fuel waste, and backfiring are avoided.

More particularly, it is an object to provide a device for eifecting automatic fuel shut-off during deceleration periods which may be readily installed in conventional automobiles without necessitating any major modification of the engine itself. Alternatively, the device is so designed that it may be readily incorporated in a conventional carburetor structure during the manufacture of the automobile engine.

More general objects of the invention are to provide a positive, direct, and inexpensive engine control device for minimizing the passing of unburned fuel through the engine to the end that air pollution is minimized, fuel economy achieved, and backfiring and the like eliminated.

Another important object is to provide a device meeting the foregoing objects which will not interfere with normal engine operation should any of its component parts break or rupture whereby a fail-safe installation results.

Briefly, these and many other objects of this invention are attained by taking advantage of variations in the intake manifold pressures existing in present day carburetor controlled internal combustion engines for drawing fuel into the cylinders. Towards this end, the device comprises a fuel cut-oif valve which is inserted between the throttle valve and intake manifold of a conventional internal combustion engine. Opening and closing of this fuel cut-off valve is controlled by changes in the intake manifold pressure which pressure in turn depends upon whether or not the car is accelerating or decelerating. The device also includes additional control means for insuring that the fuel cut-off valve will be open when the engine is merely idling. Moreover, each of the components are so designed that should a failure occur in any one or all of them, the fuel cut-off valve will be actuated to an open position so that normal functioning of the automobile can take place.

A better understanding of the preferred embodiment of the invention will be had by referring to the accompanying drawing which shows the fuel cut-off control device in cross sectional schematic form incorporated between the throttle control valve and intake manifold of an internal combustion engine.

Referring to the drawing, there is shown a portion of a carburetor block 10 provided with the conventional throttle butterfly valve 11 arranged to be moved between the closed solid line position to the open dotted line position through an actuating rod 12 coupled to the accelerator foot pedal (not shown). Fuel is passed into the carburetor passage through a nozzle 13 from a fuel bowl 14 to mix with air passing into the block at the upper opening 15 and through the venturi section 16, all as well known to those skilled in the art. A by-passage and idle adjust 17 is provided for passing a small quantity of fuel below the throttle valve 11 to maintain the engine idling when the throttle valve 11 is substantially closed.

conventionally, the carburetor block 10 would fit directly on top of the intake manifold shown at 18. In accordance with the present invention, the block 10 is separated from the entrance to the intake manifold 18 and the control device inserted therebetween. This device includes a fuel cut-off valve body 19 housing a fuel cut-off valve 20 which may be in the form of a butterfly valve similar to the throttle valve 11. As shown, the cut-01f valve 20 is arranged to be operated from the closed solid line position to the open dotted line position by an eccentric pivot member 21 coupled through an actuating rod 22 to a valve operating servo 23.

The servo 23 includes a first flexible diaphragm 2'4 and a first biasing means in the form of a spring S normally urging the diaphragm 24 towards its dotted line position to move the actuating rod 22 and eccentric pivot 21 in a counter clockwise direction as viewed in the drawing thereby holding the fuel cut-off valve 20 in its open dotted line position. The side of the diaphragm 24 opposite to that side to which the actuating rod 22 is connected is subject to a control pressure communicated thereto through a manifold pressure line 25. The application of this control pressure in turn is controlled by a control servo 26 including a second diaphragm 27 having one end connected to a valve stem 28 terminating in a valve head 29. A second biasing means in the form of a spring S urges the other side of the dipahragm 27 in a direction to seat the valve head 29 on a valve seat 30 to terminate communication of control pressure from the manifold pressure line portion 31 to the line 25. A valve head body 32 is provided for housing the valve head and includes a small air passage 33 open to the atmosphere and arranged to register with a transverse bore 34 in the valve stem 28 when the valve head 29 is seated on the valve seat 30. Thus, when the diaphragm 27 is in the dotted line position and the valve head 29 is seated, the valve control servo 23 will be subject to a control pressure corresponding to atmospheric pressure.

The upper side of the second diaphragm 27 is subject to the pressure existing in the line 31 through a branch passage 35. The passage 31 in turn connects to a bore 36 in the fuel cut-off valve body 19 opening out under the fuel cut-off valve 20. The pressure in the bore 36, manifold pressure line 31, and branch passage 35 is thus determined by the intake manifold pressure at the entrance of the intake manifold 18.

In addition to the foregoing structure, the control device also includes a disengaging servo 37 provided with a third diaphragm 38 one side of which is connected to an actuating means 39 terminating in a camming lever '40 pivoted at 41 for rocking movement between the solid and dotted line positions as shown. The upper end of the camming lever 40 includes a cam engaging surface 42 engaging the eccentric pivot 21 of the fuel cut-off valve '20. The arrangement is such that movement of the actuating means 39 from the solid to the dotted line position Will rotate'the cam lever 40 about the pivot 41 in a clockwise direction so that the cam engaging surface 42 will force the fuel cutofi valve 20 from its solid to its dotted line position. A third biasing means in the form of a spring S exerts a biasing pressure against the other side of .the diaphragm 38. This other side of the diaphragm is also subject to a pressure through a pressure line '43 connecting with a bore 44 in the block 19 opening out between the throttle valve 11 and fuel cut-off valve j The first, second, and third servos '23, 26, and 37 are each provided with small bores '45, 46, and 47 respectively so'that'their one sides to" which their actuating elements are secured are all subject to atmospheric pressure and movement of the respective diaphragms is determined by the pressures to which the other sides of the diaphragms are subject.

'With the foregoing arrangement, it will be noted that the carburetor block 10, valve block 19,"and intake manifold entrance 18 together with the throttle valve 11 and fuel cut-off valve 20 define three distinct pressure regions. The first region above the throttle valve 11 is designated A and the pressure in this region is normally atmospheric pressure. The second region is designated B and exists between the throttle valve 11 and the fuel cut-off valve '20. The pressure in this region is normally less than atmospheric pressure. Finally, there is the third region C below'the fuel cut-off valve 20 which corresponds to the pressure existing at the intake manifold 18. The control servo 26, andin certain instances, the valve servo 23 are subject to the intake manifold pressure at the region C, while the disengaging servo 37 is subject to the'pressure between the throttle valve 11 and cut-off valve 20 in the region B.

The forces exerted by the various biasing means constituting the springs S S and-S are adjusted in accordance with the particular operting characteristics of theinternal combustion engine to which the device is applied. -For a conventional eight cylinder automobile engine, the spring S exerts a biasing force suflicient to move the diaphragm 24 from the solid to the dotted line position-only if'the pressure communicated to the diaphragm 24 through the line 25 exceeds approximately four-fifths. atmospheric pressure. In other words, the spring S is relatively sensitive and doesnot exert a very large pressure on the diaphragm 24. 'The spring S for theservo 26, on the -other hand,-exerts a pressure sufficient to move the diaphragm 27 fromthe solid to the dotted line position only solong as the pressure communicated through the branch-line '35 exceeds approximately one-fifth atmospheric pressure. The spring S thus exerts a much greater force than the spring S in the ratio of about 4 to 1. Finally, the spring S is adjusted to exert an intermediate pressure on the diaphragm 38 and will move the diaphragm from its solid to its dotted line position only so long as the pressure passed through the line 43 exceeds about three-fifths atmospheric pressure.

The operation of the control device will now be described. Assume first that the throttle valve 11 and fuel cut-off valve 20 are in their dotted line positions and that the automobile in which the engine is incorporated is cruising along at normal speed. Under such cruise conditions the intake manifold pressure in the region C exceeds one-fifth atmospheric pressure and, therefore, the diaphragm 27 of the control servo 26 will be held in its dotted line position by the spring S In such dotted line position, atmospheric pressure is communicated to the servo 23 through the bore 33in the valve headblock 32,

transverse bore 34 in the valve stem 28 and manifold pressure line 25, and normal intake manifold pressure is blocked from the servo. With substantially atmospheric pressure exerted on the diaphragm 24 of the servo 23, the spring S holds the diaphragm 24 in its dotted line position thereby holding the fuel cut-ofi valve 20 in its dotted line or open position. The pressure in the region B between the throttle valve 11 and fuel cut-off valve 20 communicated through the bore 44 and pressure line 43 to the servo 37, will correspond substantially to the pressure in region C during cruising and this pressure will ordinarily hold the diaphragm 38 in its solid line position so that the camming lever 40 will be in its solid line position and the cam engaging end 42 will be out of engagement with the fuel cut-off valve 20 when this valve is in its dotted line open position.

If new the operator of the vehicle lifts his foot from the accelerator pedal to swing the'throttle valve 11 from the open dotted line position to the closed solid line position as indicated by the arrow in the drawing, the pressure in region B immediately under the throttle valve 11 will decrease but this decreased pressure will not affeet the disengaging servo 37 since it is already in its solid line position. At the same'time, however, the pressure in region C at the intake manifold will also decrease, this decreased pressure being communicated through the bore 36 and

lines

31 and 35. The decreased pressure in line 35 will result in the diaphragm 27 moving from the dotted to the solid line position thereby raising the valve head "29 and cutting off atmospheric pressure through the bore 33 to the servo 23. Simultaneously, lifting of the valve head 29 will communicate the reduced pressure in region'C of the intake'manifold through the line 31 and pressure manifold line 25 to the servo 23 and this reduced pressure will immediately result in the diaphragm 24 moving from the dotted to the solid line position thereby retracting the actuating rod 22. This movement is communicated through the coupling to the eccentric pivot 21 to rotate i the fuel cut-elf valve 21 from the dotted to the solid line position thus immediately cutting 'ofi flow of fuel past the throttle 11 or from the idler passage to the intake manifold 18 of the engine.

Now should the throttle '11 be immediately opened or the'eng ne accelerated resulting in a sudden increase in the pressurein region B,"the diaphragm 38 of the disengaging servo 37 willmove to the dotted line position and the cam engaging surface 42 will move to its dotted line position, the valve 20 thereby being immediately opened to its dotted line position to' pass fuel to the engine. The disengaging servo thus'insures that the fuel cut-oif valve will open at any time that the throttle valve "11 is opened.

Assuming that the operator continues to decelerate so that the throttle valve 11 remains closed for an appreciable period of time, the intake manifold pressure at the region C will be maintained at a relatively low value because of the continued turning overof the engine, and the fuel cut-ofi valve 20 will remain in its closed position so long as the pressure applied through the line 35 to the control 'servo 26 is less than abOutone-fifth atmospheric pressure. As deceleration continues towards an idling condition,'the manifold'pressure in region C gradually increases to a value at whichthe relatively strong spring S in the servo26 can move the diaphragm 27 from its solid to its-dotted line position therebycutting ofi communication of manifold'pressure through the line 31 and the line 25 to'the servo 23 and simultaneously passing atmospheric pressure to the servo 23. Thus, the spring S willmove the diaphragm 24 from its solid to its dotted line position and thereby through the actuating rod 22 also rotate the eccentric pivot 21 in a counter clockwise direction to open the fuel cut-01f valve-20 and preventthe engine from dying. V

Summarizing the foregoing operation, it will be noted that the control servo 26 will normally respond to pressure in the region C at the intake manifold as a consequence of closing ofi of the throttle valve 11 to move the diaphrgam 27 from the dotted to the solid line position and thus communicate this intake manifold pressure to the valve servo 23. This servo in turn moves from the dotted line to the solid line position to close the fuel cutoff valve 20 thereby conserving fuel while the throttle valve 11 is closed as is the case under decelerating conditions. When deceleration approaches an idling

condition servos

26 and 23 open the fuel cut-off valve 20. When the throttle valve 11 is opened prior to complete deceleration to accelerate the engine, the pressure change reflected in the region B will actuate the disengaging servo 37 to move from the solid to the dotted line position and thus immediately open up the cut-off valve 20 so that normal cruising can be resumed or acceleration can take place. Upon initial cracking of the fuel cut-oif valve 20, the intake manifold pressure in the region C will increase so as to actuate the control servo 26 from its solid to its dotted line position thereby shutting off the manifold pressure from the servo 23 so that the spring S can move the diaphragm 24 to its dotted line position thereby also acting to open the fuel cut-off valve 20.

The disengaging servo 37 is thus a most important feature of the invention in that it will insure absolute control by opening the fuel cut-off valve immediately upon opening of the throttle valve 11 thereby enabling acceleration to take place.

The control servo 26 which controls the pressure supplied to the valve servo 23 in turn is important in that it is sensitive to the change in manifold pressure as the engine approaches idling and upon actuation automatically subjects the servo 23 to an atmospheric pressure so that the shut-off valve will be immediately opened before the engine slows to the extent that it may die.

As mentioned heretofore, the sensitivities of the respective springs can be adjusted in accordance with the operating characteristics of the particular engine under consideration.

From the foregoing description, it will be evident that the present invention has provided a direct and inexpensive means for automatically cutting ofi the fuel flow to an internal combustion engine during deceleration periods without the possibility of the engine inadvertently dying. Moreover, it will be evident from the construction described that the device can be inserted in conventional engines or alternatively formed as an integral part of the carburetor body during engine manufacturing.

In addition, should any one or more of the diaphragms rupture, the associated spring will always urge the diaphragm to its dotted line position so that the fuel cutoff valve is held open and normal operation of the engine can take place.

Modifications that fall within the scope and spirit of the present invention will readily occur to those skilled in the art. The engine control device is, therefore, not to be thought of as limited to the specific embodiment set forth for illustrative purposes.

What is claimed is:

1. A control device for automatically cutting off the flow of fuel into the intake manifold from the throttle valve and idle adjust of an internal combustion engine in response to deceleration of said engine, comprising, in combination: a fuel cut-off valve positioned between said throttle valve and said intake manifold; a valve servo connected to move said cut-off valve between opened and closed positions in response to varying pressures in said intake manifold; and a disengaging servo connected to move said valve from a closed to an open position in response to opening of said throttle.

2. The subject matter of claim 1, in which said valve servo is operated to open said valve in response to a change from the pressure existing at said intake manifold during said deceleration to the pressure existing at said intake manifold when said engine is idling.

3. The subject matter of claim 1, including a control servo connected to control the transmission of pressure variations at said intake manifold to said valve servo, said control servo being responsive to changes in pressure at said intake manifold.

4. A control device for automatically cutting off the flow of fuel into the intake manifold from the throttle valve of an internal combustion engine, comprising, in combination: a fuel cut-off valve positioned between said throttle valve and said intake manifold; a valve operating servo including a first diaphragm having one side exposed to atmospheric pressure and its other side subject to a control pressure, said valve operating servo further including an actuating rod connecting said one side of said first diaphragm to said valve and a first biasing means urging said first diaphragm and actuating rod in a direction to hold said valve open only so long as said control pressure is greater than a first given fraction of atmospheric pressure; a manifold pressure line connected between said intake manifold and said valve operating servo for passing said control pressure to said other side of said first diaphragm; a control servo including a second diaphragm having one side exposed to atmospheric pressure and its other side subject to the pressure at said intake manifold, said control servo further including a control valve head connected to said one side of said second diaphragm and positioned within said manifold pressure line, and second biasing means urging said diaphragm and control valve head in a direction to close oif said manifold pressure line and open said other side of said first diaphragm to atmospheric pressure thereby changing said control pressure from the pressure existing at said intake manifold to atmospheric pressure only so long as said intake manifold pressure is greater than a second given fraction of atmospheric pressure, said second given fraction being less than said first given fraction; and a disengaging servo including a third diaphragm having one side exposed to atmospheric pressure and its other side subject to the pressure existing between said throttle valve and said fuel cut-off valve; said disengaging servo further including an actuating means having one end connected to said one side of said third diaphragm and its other end terminating in a cam means adjacent said fuel cut-off valve; and a third biasing means urging said third diaphragm and actuating means in a direction to cam open said fuel cut-off valve only so long as said pressure between said throttle valve and said fuel cut-oif valve is greater than a third given fraction of atmospheric pressure, said third given fraction lying between said first and second given fractions.

5. The subject matter of claim 4, in which said first given fraction is said second given fraction is ,6, and said third given fraction is References Cited in the file of this patent UNITED STATES PATENTS 2,017,878 Vanderpoel Oct. 22, 1935 2,129,608 Vanderpoel Sept. 6, 1938 2,359,230 Mallory Sept. 26, 1944 2,395,748 Mallory Feb. 26, 1946 2,544,607 Mallory Mar. 6, 1951