US3768368A

US3768368A - Fuel viscosity and density sensing fuel pump rack stop

Info

Publication number: US3768368A
Application number: US00196159A
Authority: US
Inventors: T Wahl; Z Krauja; S Kranc
Original assignee: Caterpillar Tractor Co
Current assignee: Caterpillar Inc
Priority date: 1971-11-05
Filing date: 1971-11-05
Publication date: 1973-10-30
Anticipated expiration: 1990-10-30

Abstract

Fuel control means for a multifuel engine for automatically varying the quantity of fuel delivered to said engine to maintain rated power output for various fuels used. The control means include means to adjust the position of a piston in response to a change in fuel density or viscosity. The piston is connected to control the fuel metering.

Description

United States Patent 1 Krauja et al.

[ Oct. 30, 1973 1 FUEL VISCOSITY AND DENSITY SENSING FUEL PUMP RACK STOP [75 Inventors: Ziedonis I. Krauja, East Peoria;

Stanley J. Kranc, Morton; Thomas V. Wahl, Jr., North Pekin, all of 111. [73] Assignee: Caterpillar Tractor Co., Peoria, 111.

[22] Filed: Nov. 5,1971

121| Appl. No: 196,159

[521 U.S. Cl 91/378, 91/52, 91/417 R, i 91/468 [51] Int. Cl. FlSb 9/10, F'l5b 15/17 [58] Field of Search 91/52, 416, 417 R, 91/376, 378; 137/549; 91/417 A, 468

[56] References Cited UNITED STATES PATENTS 2,413,380 12/1946 Rush et al. 91/417 R 2,764,868 10/1956 Watson et al. 91/417 R 2,884,905 5/1959 Jensen 91/52 2,924,241 2/1960 Bauer r 137/549 2,988,102 6/1961 Harry et al.. 137/549 3,363,517 1/1968 Powers 91/416 3,411,412 11/1968 Phipps r 91/52 3,646,849 3/1972 Smith 91/52 Primary Examiner-Paul E. Maslousky AIIorm-y FrcIing 1 1, Baker et al.

[57] ABSTRACT Fuel control means for a multifuel engine for automatically varying the quantity of fuel] delivered to said engine to, maintain rated power output for various fuels used. The control means include means to adjust the position of a piston in response to a change in fuel density or viscosity. The piston is connected to control the fuel metering.

10 Claims, 2 Dravving Figures PAIENIEDum 30 I973 (-3. 768,368

SHEET 1 c? 2 YNVENTORS ZIEDONIS LKRAUJA STANLEY J. KRA NC THOMAS V. WAHL,JR

BY '7", W4, 2 74.x, 4M

ATTORNEYS PAIENTEDum 30 ms 3,768,368 SHEET 2 CF 2 INVENTORS ZIEDONIS LKRAUJA STANLEY J, KRANC THOMAS V. WAHL, JR

BY a wl, 9a,, M 4% ATTORNEYS FUEL VISCOSITY AND'DENSITY SENSING FUEL PUMP RACK STOP BACKGROUND OF THE INVENTION The present invention relates to fuel control means for multifuel engines, and pertains more particularly to viscosity and/or density responsive means for controlling the volume of fuel injected into an engine.

It is often desirable to be able to operate an engine on a variety of fuels, and especially in military applications it is often essential. However, because the heat value of different fuels vary for a given volume, and fuel metering is commonly on a volume basis, it is necessary to adjust the fuel metering setting each time a different fuel is used in order to obtain satisfactory power from the engine.

Both manual and automatic adjustment of fuel metering means have been proposed. Manual adjusting means have proven unsatisfactory because the operator sometimes either forgets or doesnt bother to adjust the setting. This results in the engine runningat either too high or too low power when different fuels are used. Automatic adjusting. means, on the other hand have been expensive and complex in construction and operation.

SUMMARY OF THE INVENTION It is a primary object of the present invention to overcome the above disadvantages in the prior art by pro-- viding simple apparatus for controlling the fuel injection system of amultiple fuel engine to obtain a consistent rated power output.

It is another object of the present invention to provide fuel control means which is responsive to fuel viscosity for controlling the amount of fuel fed into an internal combustionengine.

Still another object of the present invention is to provide control means for varying the volume of fuel in multi-fuel engines which utilizes the proportional relationship between the density of the fuel and the heating value of the fuelfor unit volume.

In accordance with the present invention control means are provided which creates differential pressure acting on a positioning valve. When thepositioning valve moves in response to a change in differential pressure, a piston moves a corresponding distance. The piston acts to position a control linkage limiting the maximum amount of fuel permitted to be fed into an engine.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross sectional view of a preferred embodiment of the present invention.

FIG. 2 is a cross sectional view of an alternate em bodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawing, and in particular, to FIG. 1, there is illustrated a preferred embodiment of the present invention, comprising a housing having an inlet 11 communicating by means of an orifice 12 with a narrow annular flow passage 13 formed by the inner surface of housing 10 and the outersurface of a cylindrical sleeve 15. Fluid or fuel at a pressure P1, such as fuel transfer pump pressure, flowing from the inlet through orifice 12 is reduced to a pressure P2 at an annular groove 14, and flows byway of a passage 16 and passage 18 to an annular groove 19 which commu= nicates with a chamber 20 through a passage2l formed in a piston 22 which is laterally mounted within the with a chamber 28. Fluid then flows from chamber 28 through an outlet 46 and orifice 45 to a drain 46a. The restriction to the flow of fluid in passage 13 subjects the fluid to a pressure reduction or pressure drop prior to entering annular groove 27 which. establishes a pressure P3 at groove 27 and in chamber 28. The pressure difference between P2 and P3 is determined by restriction to fluid flow in passage 13 and fluid viscosity, causing pressure P3 to be normally lessthan pressure P2.

The force of pressure P2 acting within chamber 20 forces valve 24 to move leftward against the force of pressure P3 and the force of a spring 30 acting upon the valve 24 in an opposite direction in chamber 28'. A leftward movement of the valve. 24 uncovers a port 32 allowing fluid in chamber 20 to communicate with a chamber 33 through a passage 34. A fluid pressure P4 is then established in chamber 33 creating a force acting to move piston 22 leftwardly to close port 32. If the fluid force in chamber 20 created by pressure P2 acting on valve 24 is greater than the opposing force created by pressure P3 acting on valve 24 plus the force of spring 30 then the valve continues to movev leftwardly and piston 22 will follow. As valve 24moves leftwardly compressing spring 30, the force of the spring acting on the valve increases until the spring force combined with the force of pressure P3 acting on valve 24equals the force of pressure P2 in chamber 20 acting on-the opposite side of the valve 24. When the opposing forces act ing on valve 24 become equal, the valve is balanced and piston 22 will reach a position of equilibrium in the following manner. With valve 24 balanced, the force of pressure P2'in chamber 20 acting on valve 24 also opposes movement of piston 22 to the left and this force pumps in the conventional manner and hasaflange 43 which contacts stop means 41 as rod member 42moves to the right, thus limiting the amount offuel injected into the engine. The rod member 42 is normally controlled in a conventional manner by a governor, which, under the. condition of. demand for maximumfuel, imposes substantial forces thereon inan attemptto move it to the right. However, the fluid trapped inchamber 33 serves as a hydraulic lock which. restrains piston .22 and, therefore, member 40from being moved by the force acting upon rod member 42.

In the operation of the mechanism, when switching: from diesel fuel to JP-4 or gasoline which arerelatively less viscous and less dense than diesel fuel, a relatively small pressure drop occurs between grooves 14 and 27, when the less viscous and dense fluid replaces the diesel fuel. This relatively smaller pressure loss or drop developed between grooves 14 and 27 establishes a smaller differential pressure between P2 and P3. Momentarily, the force of spring 30 combined with the force created by pressure P3 in chamber 28 acting on valve 24 becomes greater than the force of pressure P2 acting in chamber 20 on valve 24 urging the valve to the right permitting port 32 and groove 36 to communicate and some fluid in chamber 33 to escape through a passage 37 in valve 24 to chamber 28 causing a reduction of pressure P4 in chamber 33..The forces acting on piston 22 to move it rightwardly are for a short period greater than the forces tending to move it leftwardly, and a rightward movement of piston 22 and member 40 takes place until a balance of forces on valve 24 and piston 22 is again reached. At this point port 32 is closed and the fluid in chamber 33 is again trapped thus creating a fluid or hydraulic lock on piston 22 which maintains stop 41 in its new position until valve 24 is again subjected to a change in the opposing forces acting on it. Valve 24 in response to each change in opposing forces acting on it then moves causing a variation in differential pressure across the piston 22 which, in turn, causes the piston to move.

Assuming that a more viscous or dense fluid such as diesel fuel was again placed in the system, a relatively large pressure drop occurs between grooves 14 and 27 as compared to the pressure drop when using the less viscous or dense fluid. This enlarged pressure differential between pressures P2 in chamber 20 and P3 in chamber 28 would have the effect of moving the valve 24 and, therefore, piston 22 to the left. To establish the maximum leftward position of rod member 40, a stop 44 is utilized within chamber 28. This stop restricts leftward movement of valve 24 which thus determines the maximum leftward movement of piston 22.

Referring now to FIG. 2, there is illustrated an alternate embodiment of present invention which constitutes a more compact arrangement than that of FIG. 1. The embodiment of FIG. 2 comprises a housing 50 having end plates or sections 51 and 52, an inlet 53 and an outlet 54. Fluid entering the inlet 53 passes through an orifice 53a and along passageway 55 and into annular groove 56 and passageway 57 to chamber 58 establishing a pressure therein which acts upon positioning valve 59, which is slidably mounted within the bore 62 of a piston 61 slidably mounted within housing 50. The fluid entering the inlet 53 also passes along a passage 63 and through a porous sintered metal element 64 and into a chamber 65 for imposing a pressure on a back side of piston 61. Fluid in chamber 65 returns through an orifice 66 and outlet 54 to the fuel tank (not shown). A spring 67 operatively engages positioning valve 59 by means of a flange 68 and biases the positioning valve 59 to the right. When positioning valve 59 moves to the left with respect to piston 61, fluid in chamber 58 can then communicate by means of passageway 69 and passage 70 to chamber 71 wherein pressure is then imposed on the right face of piston 61. Movement of positioning valve 59 to the right with respect to piston 61 causes passageway 69 to move into communication with a port 72 and a passage 73 allowing fluid to flow between chamber 65 and 71 to achieve rightward movement of piston 61.

This embodiment operates in substantially the same manner as the previous embodiment of FIG. 1 with the porous sintered element 64 serving to create a pressure drop between the inlet 53 and chamber 65 in place of an annular orifice. Thus a differential pressure is imposed initially on piston 61 by means of the differential pressure existing between

chambers

65, 58 and 71. Also, as in the previous embodiment when the piston is moved to permit a balancing of the pressure forces, the positioning valve 59 will have been moved to position to create or impose a hydraulic lock on piston 61 by virtue of trapped fluid in chamber 71. This lock prevents rightward movement of the piston and the stop 74 carried by control rod 75.

We claim:

1. A fuel regulating system for an internal combustion engine, said system comprising:

a housing having a cylindrical chamber formed therein;

a piston reciprocally mounted in said-chamber;

a control rod connected to said piston and extending from said housing;

an inlet to communicate a flow of fuel into said chamber from a pressure source;

means for imposing a differential pressure on said piston from said fuel,

said differential pressure means comprising an uninterrupted first flow path for directing a portion of said fuel to one side of said piston and a second flow path including a pressure responsive positioning valve disposed in said piston for directing fuel to the other side of said piston; and

an outlet in said housing communicating with said chamber to said one side of said piston and including restricting means.

2. The apparatus of claim 1 including spring means acting on said positioning valve and one side of said piston; and,

restricting means including an annular passageway in said first flow path.

3. The apparatus of claim 1 comprising means including said positioning valve for inducing a fluid lock on the other side of said piston.

4. The apparatus of claim 1 wherein said first flow path includes means including an annular passageway surrounding said chamber to induce a pressure drop between said inlet and said one side of said piston communicating with said outlet.

5. The apparatus of claim 4 wherein said means to induce a pressure drop comprises an elongated annular passageway surrounding said cylindrical chamber.

6. The apparatus of claim 4 wherein said means to induce a pressure drop comprises an annular porous element mounted in said chamber.

7. A viscosity responsive fuel control system, said system comprising:

a housing including a cylindrical bore and means to enclose said bore;

a piston, including a control rod, reciprocally mounted in and dividing said bore into first and second chambers,

inlet 'means including first and second conduit means to convey pressurized'fuel into said first and second chambers;

flow restricting means in said first conduit means;

a pressure responsive control valve and at least a portion of said second conduit means disposed in said piston, and said control valve being operative to control said second conduit means;

said control valve being biased in one direction by the inlet pressure of said pressurized fuel, and in the opposite direction by spring means;

said valve means being operative, in a first position to communicate said pressurized fuel to said sec- I end chamber, in a second position to block said communication, and in a third position to provide communication between said first snd said second chambers; and,

an outlet including restricting means communicating with said first chamber.

8. The control system of claim 7 wherein said spring stricting means comprises an-annular porous element disposed in said second chamber.

Claims

1. A fuel regulating system for an internal combustion engine, said system comprising: a housing having a cylindrical chamber formed therein; a piston reciprocally mounted in said chamber; a control rod connected to said piston and extending from said housing; an inlet to communicate a flow of fuel into said chamber from a pressure source; means for imposing a differential pressure on said piston from said fuel, said differential pressure means comprising an uninterrupted first flow path for directing a portion of said fuel to one side of said piston and a second flow path including a pressure responsive positioning valve disposed in said piston for directing fuel to the other side of said piston; and an outlet in said housing communicating with said chamber to said one side of said piston and including restricting means.

2. The apparatus of claim 1 including spring means acting on said positioning valve and one side of said piston; and, restricting means including an annular passageway in said first flow path.

7. A viscosity responsive fuel control system, said system comprising: a housing including a cylindrical bore and means to enclose said bore; a piston, including a control rod, reciprocally mounted in and dividing said bore into first and second chambers; inlet means including first and second conduit means to convey pressurized fuel into said first and second chambers; flow restricting means in said first conduit means; a pressure responsive control valve and at least a portion of said second conduit means disposed in said piston, and said control valve being operative to control said second conduit means; said control valve being biased in one direction by the inlet pressure of said pressurized fuel, and in the opposite direction by spring means; said valve means being operative, in a first position to communicate said pressurized fuel to said second chamber, in a second position to block said communication, and in a third position to provide communication between said first snd said second chambers; and, an outlet including restricting means communicating with said first chamber.

8. The control system of claim 7 wherein said spring means is a compression spring disposed in said first chamber and having one end engaging said housing and the other end engaging said valve, so that the bias of said spring on said valve is a function of the position of said piston in said bore.

9. The control system of claim 8 wherein said restricting means in said first conduit means comprises an elongated annular passageway surrounding said bore and extending substantially the length thereof.

10. The control system of claim 8 wherein said restricting means comprises an annular porous element disposed in said second chamber.