JPS6388270A - Double spring type air fuel controller - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates generally to air-fuel control systems for internal combustion engines, and more particularly to compression ignition internal combustion engines in which fuel is supplied to the engine cylinders depending on air pressure in the intake manifold. The present invention relates to a double spring type air-fuel control device for use in a vehicle.

BACKGROUND OF THE INVENTION The regulation of air-fuel mixtures supplied to internal combustion engines, particularly compression ignition engines, has received widespread attention. If a satisfactory air/fuel ratio is not achieved within the engine cylinders, engine operation will be adversely affected and fuel economy will be reduced. Proper adjustment of the air/fuel mixture can substantially eliminate or reduce undesirable emission components from the engine exhaust. Air and fuel are supplied to the cylinders in carefully controlled ratios that allow for complete combustion under all operating conditions to eliminate exhaust emissions and achieve acceptable vehicle emissions control. The device can be completely dispensed with. Furthermore, efficient and economical engine operation is also achieved.

Fuel systems for internal combustion engines are known in which the fuel supplied to the engine is controlled in response to intake manifold pressure.

Many such fuel systems include a pressurized fuel source, such as a fuel pump, and a mechanism for regulating the pressure of the fuel delivered to the injectors located in each cylinder. Extremely sophisticated improvements in the basic components listed above to enable carefully scheduled pressure output as a function of operator demand and engine speed to achieve optimal air/fuel ratio under all operating conditions. has been carried out.

Such improved systems are exemplified in Wilson et al., US Pat. No. 4,187.817 and Wilson et al., US Pat. No. 4,248.188. The air/fuel control mechanism described in these U.S. patents mechanically directs the flow of fuel into the engine in response to air pressure varying from a "no air" condition below the rated pressure level in the intake manifold to full rated pressure. Adjust accordingly. Both systems use a diaphragm or flexible bellows type actuator to operate the fuel flow control valve in response to engine intake manifold air pressure sensed via an air line connecting the diaphragm type actuator to the intake manifold. The diaphragm is biased by a single spring selected and calibrated to adjust the valve throttle, varying fuel pressure in response to intake manifold pressure to achieve optimal air/fuel ratio over a wide range of operating conditions. considered maintainable. Drain lines are added to these systems to provide fluid communication between the air/fuel control system and the engine fuel tank.

The air/fuel control system disclosed in the '817 patent further prevents pressurization of the engine fuel tank and backflow of fuel into the engine intake manifold upon failure of the diaphragm actuator. The air/fuel control system of U.S. Pat. No. 4,248,188, which also includes a flow restrictor in the air line, provides fuel to the control chamber at a rate faster than the rate at which fuel is discharged from the control chamber. These air/fuel control systems, which include damper assemblies that dampen the transient response of the diaphragm actuator, are generally capable of achieving proper air/fuel ratios or very precisely controlled metering of fuel. is difficult to achieve and therefore the optimum air/fuel ratio is not necessarily achieved for all engine operating conditions, and
Variations in backpressure, which are characteristic of conventional air/fuel control systems, have caused the delay of the air/fuel control system to vary, resulting in response problems. Furthermore, marine engines cannot use drain lines such as those provided in conventional air-fuel control systems. When the diaphragm fails in conventional air/fuel control systems in marine engines, such as those described in the aforementioned US patents, fuel tends to collect in the bilge.

Other air/fuel control systems using diaphragm type actuators are also available.
For example, U.S. Pat. No. 3,795,233 to Cruz et al., which is well known in the art, discloses a system that includes a governor means connected to a fuel conditioning member and a supercharger that supplies air to the engine via an intake manifold. A control device for a supercharged engine is disclosed. In this control system, three spring members are used to balance the forces on the diaphragm when no pressure is present in the control system chamber on the intake manifold side of the diaphragm. This system is responsive to both intake air pressure and engine oil pressure to override the governor means. However, the system described in that patent does not include a fuel flow control valve and uses a mechanical linkage to vary the fuel delivered to the engine upstream of the throttle valve.

Furthermore, none of the air-fuel control devices proposed in the prior art are completely tamper-proof, and inaccurate manipulation of the internal combustion engine's fuel supply will have a negative impact on fuel efficiency and long-term engine fire resistance. A fuel system such as that described in the aforementioned U.S. patent generally includes a drain line leading to the fuel tank for returning fuel that has not been injected into the engine cylinders or has escaped from within the gear pump section of the fuel pump; It is widely known that the short-term power output of an engine with such a fuel system, including an adjustable air screw in the engine, can be increased by tightening the train line and opening the air screw. . However, these unauthorized modifications can have extremely negative effects, such as loss of fuel efficiency and shortened engine life. Furthermore, such modifications change engine emissions from those obtained with air/fuel control settings set by the engine manufacturer, causing the engine to no longer meet government-established emissions standards.

[Problem to be Solved by the Invention] Therefore, the conventional technology quickly responds to the optimal amount of fuel controlled according to the air pressure of the intake manifold, and the air-fuel control device or the engine is mounted on the engine. It does not present an air/fuel control system for an internal combustion engine that cannot be adjusted or modified.

SUMMARY OF THE INVENTION Therefore, the main object of the present invention is to eliminate the drawbacks of the prior art described above.

Another object of the present invention is to provide an air/fuel control system for an internal combustion engine that rapidly responds to changes in intake manifold air pressure and meters a controlled amount of fuel.

A further object of the invention is to include a diaphragm-based actuator for a fuel flow control valve, the diaphragm-based actuator having a pair of oppositely directed diaphragm-based actuators positioned on either side of the diaphragm-based actuator for controlling the position of the control valve in response to air pressure in the intake manifold. An object of the present invention is to provide an air-fuel control device for an internal combustion engine having a bias spring.

Another further object of the invention is to receive the barrel within the air/fuel control device housing so as to ensure a high precision fit between the plunger and the barrel to minimize fuel leakage. An object of the present invention is to provide an air/fuel control device including a diaphragm-operated fuel flow control valve having a contoured valve plunger.

Another object of the present invention is to provide a barrel and plunger assembly for an air/fuel control bladder that includes internal differential pressure control means to substantially eliminate fuel leakage from the barrel and plunger assembly.

Yet another object of the invention is that the engine is not adjustable on the engine;
An object of the present invention is to provide an air/fuel control device for an internal combustion engine that must be removed from the engine before adjustment can be made.

Yet another object of the present invention is to provide an air/fuel control system for an internal combustion engine that drains excess fuel internally into the engine's crankcase, thus eliminating the need for a drain line connecting the air/fuel control system to the engine's fuel tank. The aim is to provide a system.

Yet another object of the present invention is to provide a plunger and barrel type system whose operation is controlled by the supplied fuel pressure to provide more precise control of fuel metering and to substantially eliminate leakage of excess fuel from the air/fuel control system. To provide a repair kit that can be replaced and mounted on an already installed engine having a diaphragm-operated fuel flow control valve and equipped with an air/fuel control g# mechanism.

[Means for Solving the Problems] Based on the above object, an air-fuel control system for an internal combustion engine is provided which has an intake manifold that is controlled in operation by the fuel pressure supplied to the engine from a fuel source and supplies air to the engine. a pneumatic responsive means for mechanically regulating the flow of fuel into the engine in response to pressure within the intake manifold containing the cavity, a pressure responsive actuation means within the cavity, and an empty line connecting the cavity to the intake manifold. An air/fuel control system is provided. A pressure responsive actuator converts pressure changes within the intake manifold into mechanical movement to operate the pressure responsive actuator. The pressure-responsive actuating means includes first and second actuators separated by a diaphragm attached to the piston.
The first chamber is connected to the intake manifold by an air line. A first main spring biases the piston toward the first chamber, and a second bias spring biases the piston away from the first chamber. The pressure-responsive actuation means further includes fuel metering means for controlling the flow of fuel into the air-fuel control system in response to air pressure in the intake manifold, the fuel metering means controlling the flow of fuel into the air-fuel control system in response to air pressure in the intake manifold. including a specially constructed barrel and plunger assembly to permit. The barrel and plunger shapes are designed to quickly and accurately meter fuel in response to changes in air pressure within the manifold, and are mated together with a precision fit to prevent excessive fuel leakage. Minimum. Additionally, internal differential pressure control means are provided within the plunger to substantially eliminate fuel leakage.

Two alternative embodiments of the barrel and plunger assembly, each with a different cross-sectional shape, are also provided. Internal vent means are further provided to direct excess fuel from the air/fuel control system into the engine crankcase.

More specific aspects of the invention other than those described above will become apparent from the accompanying drawings and the following description of the embodiments.

Examples The type of fuel system in which the present invention can be used is found in compression ignition internal combustion engines that are controlled by the pressure of the fuel supplied from the fuel supply system. This type of engine includes multiple cylinders into which fuel is injected by fuel injectors, each fuel injector being actuated synchronously with the movement of the engine piston. The actual amount of fuel injected into each cylinder depends on the pressure of the fuel supplied to the common rail or line by the fuel supply system. Also, the pressure of that fuel is determined by a scheduled pressure output as a function of operator demand, generally dictated by throttle valve position, and as a function of engine speed.The fuel delivery system for which the present invention is ideally suited is No. 4,187,817 and No. 4,248,188, assigned to the same assignee as unissued Ill.

Achieving an optimal and accurate air/fuel ratio within each engine cylinder is particularly important in turbocharged engines where the intake pressure drops below rated pressure under certain operating conditions. Therefore, the ability to mechanically regulate and control the flow of fuel into the engine in response to air pressure within the intake manifold is essential to efficient engine operation. Also, maintaining the air/fuel ratio within a predetermined operating range that cannot be adjusted while the air/fuel controller is mounted on the engine and requires the air/fuel controller to be removed from the engine. is also essential to efficient engine operation and achieving acceptable exhaust emission levels.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, FIG. 1 illustrates an air/fuel control system 10 that can be advantageously used to achieve and maintain adequate delivery of fuel into cylinders in response to pressure within an intake manifold. The relevant parts of the engine fuel supply system are also shown in FIG. These parts include fuel pump 12 and gear pump 14. Either air line 16 or cover plate 18 provides direct communication between the engine intake manifold (not shown) and the interior of the air/fuel control system.

To fully understand the present invention, it is important to understand the operation of air/fuel control system N10 and the pressure within the engine intake manifold.

It will be necessary to explain how the air/fuel control system operates in regulating the flow of fuel to the internal combustion engine in response to power; for this purpose, reference is made to FIG. FIG. 2 shows a cross-sectional view of air/fuel control system 10 taken along line 2--2 of FIG. 1, with cover 18 rotated 90 degrees counterclockwise for illustrative purposes. Figure 2 also shows the state of the air-fuel control system when the pressure in the intake manifold is lower than the rated pressure level. When there is “no air”
A condition arises.

The air-fuel control device 10 includes a housing 20 having a control chamber 22.
The control chamber 22 is subdivided into a first chamber 24 and a second chamber 26 by a flexible bellows member or diaphragm 28 . Diaphragm 28 is operatively coupled to one end of a stem valve 30 with plunger 32 . The other end of the stem valve 30 is attached to the piston 34 by a nut 36. Nut 36 is also used to removably secure to piston 34 a diaphragm retainer 38 that engages the inner edge of diaphragm 28. The outer edge of the diaphragm 28 engages the cover 18 of the air/fuel control system.

The piston 34 and diaphragm retainer 38 are preferably formed of stamped steel or the like, and the flexible hollow member or diaphragm 28 should be formed of a material capable of withstanding a differential pressure of at least 150 bonds per square inch (psi). It is. For this purpose, diaphragms constructed from double-sided coated woven fabric have been found to work well. An example of a material for the diaphragm 28 that can withstand the above differential pressure is 100% diaphragm 28 coated on both sides with an elastomer such as 70% fluorosilicone/30% silicone rubber containing a filler.
% Dacron woven fabric. However, other equivalent materials can of course also be used.

- a set of oppositely biased dual springs is provided in the control chamber 22 to bias the piston 34 towards the cover 18 of the air/fuel control system when the intake manifold pressure is below the rated level; Cover 1 as intake manifold pressure increases
8. Forces it in the direction away from 8. The main spring 40 is in the second chamber 2
6 and acts toward the cover 18 and comes into contact with the piston 34, so that the piston 34 is biased toward the cover 18. A second or biasing spring 42 is biased away from the cover 18 and thus applies a force on the piston 34 in the opposite direction of the primary spring 40 .

A biasing spring 42 is located around the nut 36 and has one end in contact with the diaphragm retainer 38. The other end of the biasing spring 42 engages a biasing spring retaining element 44 which is held in position within the gSlSl chamber 4 by an inner end 46 of a threaded adjustment screw 48. The other end 50 of the adjustment screw 48 extends outwardly from the control chamber 22 through the cover 18 and engages a corresponding threaded nut 52 located on the exterior of the cover 18. Therefore, the longitudinal expansion of the bias spring 42 is controlled by the bias spring adjustment screw 48 in the control chamber 22.
The distance extending inward is 3J! It can be controlled by li. The operational significance of these features of the air-fuel control system will be discussed in more detail below.

The air/fuel control device cover 18 includes an air supply passage 55 formed in its thickened portion 57, which passage 55 is in direct connection with the air line 16 and thus with the intake manifold of the engine. Air from the intake manifold enters the first chamber 24 of the air/fuel control system along the path indicated by arrow 59.

The cover 18 of the air-fuel control device further includes a thick cover portion 57.
a central quadrant 54 defined between and a peripheral boss 53;
The end 50 of the adjusting screw 48 now protrudes through the cover 18 and engages the nut 52. The cover of the air-fuel control device is located close to the engine flock, so when the air-fuel control device is installed on the engine, [! ! Access to the screw 48 is blocked and inaccessible, so adjustment of the "airless" position of the bias spring and therefore the piston and attached structures is only possible by removing the air/fuel control system from the engine and placing it on the fuel pump test stand. This can only be done after it has been installed. For this reason, it is virtually prohibited in this invention to make unauthorized modifications to the "no air" setting of the air/fuel control system while the air/fuel control system is in place on the engine. It is an unavoidable source. This point is a significant difference compared to conventional air/fuel control systems that are designed to be adjustable while attached to the engine.

As a further tamper-proof measure, the adjustment screw 48 is tightly fitted over the end 50 and the nut 52 in the recess 54 between the thickened portion 57 of the air-fuel control cover and the peripheral boss 53, so that both structures A cap 51 may be provided which completely covers the member.

For this purpose, a cap 51 having a cross-sectional shape as shown in FIG. 2 is preferred. However, other structural members that perform the same function may be used to prevent unauthorized adjustment of the stud 48 after the air/fuel control system has been set up by the manufacturer and installed in place on the engine.

As mentioned above, the stem valve 30 is located in the central hole 3 of the barrel 31.
The barrel 31 is mounted within a cavity 23 inside the air/fuel control system 6 housing 20. The shape of the plunger and barrel are specifically designed to accommodate both "airless" and "relaxation" pressures that occur within the fuel supply rail, as discussed in connection with FIGS. 3 and 4 below. As a result, the "airless" adjustment normally required at the fuel pump in conventional air-fuel control systems is not required when using the air-fuel control system of the present invention.

Plunger 32 includes a central longitudinal channel 35 extending from plunger tip 37 toward second chamber 26, as shown in phantom in FIG.

Aperture 39 provides fluid communication between channel 35 and barrel center bore 33 to minimize leakage of fuel from the barrel, as discussed in more detail below.

When the air/fuel control system stem valve 30 is in the position shown in FIG.
, where fuel enters the controller through inlet port 58 and then through outlet passage 62 to exit port 6.
It shows that it comes out from 4. An inlet bypass passageway 66 is formed within the housing 20 between the inlet port 58 and the cavity 23 that receives the barrel 31. An outlet bypass passage 68 is also formed within the housing 20 to direct fuel away from the barrel 31. The inlet and outlet bypass passages 66.68 are aligned with first and second annular yt70.72, respectively, formed on the outer surface of the barrel. Grooves 70, 72 communicate with barrel fuel inlet passage 74 and barrel fuel outlet passage 76, respectively.

Barrel 31 is seated within cavity 23 of air/fuel control housing 20 by an annular retaining ring 78 and a plurality of annular O-ring type seals 80 spaced apart along the outer surface of the barrel.

Preferably, there are at least four such O-rings to provide a reliable substantially leak-free seal around the barrel 31. Furthermore, the compression spring 82 or the housing 20
is located within a recess in the air-fuel controller housing to bias the barrel toward the retaining ring 78 to securely hold the barrel and plunger assembly in place within the air/fuel control housing.

゛ When the plunger 32 is in the position shown in Figure 2,
The flow of fuel from the inlet passage 66 to the outlet passage 68 through the barrel 31 is blocked by the plunger. This situation occurs when the air pressure in the intake manifold is well below its rated value, or when there is an "airless" or zero pressure condition. In this state, the main spring 40 is
4 Thus, to bias the stem valve 30 and plunger 32 toward the cover 18 of the air/fuel control system, a small fuel flow surface gap is formed between the undercut edge 60 of the barrel and the profile of the plunger. This allows “no air”
Fuel enters the central hole 33 and flows through the fuel passage 76 of the barrel. The biasing spring 42 is biased by the piston toward the spring retaining element 44 and compressed by an amount dependent on the position of the spring retaining element 44, as shown in FIG. As previously mentioned, its position can be adjusted by rotating the threaded adjustment screw 48, and is set before installing the air/fuel control device in the engine, and the diaphragm 2
The magnitude of the vertical movement of the plunger 32 in response to the intake air pressure applied to the plunger 8 is controlled.

As air pressure within the intake manifold increases, air enters the air/fuel control system via supply passage 55.

The first chamber 24 begins to be filled. As the air pressure within the first chamber 24 increases, pressure is applied to the diaphragm 28, diaphragm retainer 38, and piston 34, compressing the main spring 40 and moving the stem valve 30 away from the cover 18 of the air/fuel control device. move it to The previously compressed bias spring 42 simultaneously begins to expand, reducing the force on the piston 34, causing the stem valve 30 and associated structural members to move toward the recess 84, causing the plunger 32 to move as shown in FIG. Move into position and turn the unit. At this point the inlet passage 74 is no longer blocked by the plunger;
An increased amount of fuel flows from the barrel cavity 23 into the central bore 33 along a path defined by the plunger profile and is available for exit via the outlet passage 76 and into the outlet bypass passage 68. Thus, the amount of fuel reaching the cylinders increases as the air pressure within the intake manifold increases.

The action of the double springs 40, 42 controls the position of the plunger in zero boost or "no air" conditions while adjusting the total available spring length of the main spring 40 and bias spring 42. The boost signal applied to the assembly when the air pressure in the intake manifold increases moves the plunger 32 by acting on the effective area of the diaphragm 28 and the combined modulus of the main spring 40 and bias spring 42. As a result, delays in the process of increasing fuel delivery to the cylinders in response to increases in intake manifold pressure are substantially eliminated.

The shape of the plunger 32 and barrel 31 of the wood air fuel controller effectively accommodates both "airless" and curved fuel rail pressures. Figures 3 and 4 show cross-sectional views of two embodiments of plunger and barrel shapes that accomplish this purpose. The plunger and barrel shapes that should be selected will largely depend on the "airless" orifice area of the engine. Both the plunger and barrel shapes shown in Figures 3 and 4 are designed to significantly minimize fuel leakage while effectively controlling the metering of fuel.

The dimensions of the plunger 32 and barrel 31 of the present invention are important to achieving optimal fuel metering.

It has been discovered that if the plunger and barrel are formed to provide a precision fit therebetween, significant reductions can be made from fuel leakage that has occurred in other air/fuel control device designs. As a result, no structural components are required for fuel drainage, and the wood-air-fuel control system a can be vented to the engine crankcase, preferably using existing flow paths. To provide the necessary clearance for a proper precision fit, the minimum inner diameter of the barrel should be approximately 0.000075 to 0.000125 inches (approximately 0.000125 inches) larger than the maximum outer diameter of the plunger.
According to test results, leakage past a barrel and plunger with clearance within the above range is approximately 1
．． Less than 0 cc/hr, which is in the same range as fuel leakage past the fuel injector and its associated barrel.

The barrel and plunger configuration shown in FIG. 3 is one example of providing effective metering of fuel in response to air pressure within the intake manifold sensed by the diaphragm and its associated structural members. Plunger 32 in FIG. 3 (same plunger shape as shown in FIG. 2) is shown along its entire length at -
The stem portion 88 is thin and does not have a different outer diameter;
The barrel shape shown in FIGS. 2 and 3, including a chamfered feature 90 having a larger average outer diameter and a stopper portion 92 having a larger diameter than either stem portion 88 or chamfered portion 90, is larger than central bore 33. diameter and fuel inlet passage 74
2, when the air/fuel control system is in the "no air" condition.

Stop portion 92 of plunger 32 allows only a small amount of fuel to flow from inlet passage 74 into barrel center bore 33 via uncut 6o. However, as the plunger moves to the position shown in FIG. 3, the chamfer 90 of the plunger 32 gradually opens the undercut 60.
As shown by arrow 86 in FIG. 3, an increasing amount of fuel flows from undercut 60 past plunger stem 88 and into central bore 33 through fuel outlet passage 76. In other words, the effective flow rate of fuel passing through the barrel 31 and past the plunger 32 depends on the size of the fuel passage formed between the plunger and the barrel when the undercut 60 opens to allow fuel to flow into the center hole 33. Much depends. Also, depending on the shape of the plunger chamfer 90 relative to the shape of the barrel center hole 33 and the 6° undercut, the shape of the stem valve 30 may be adjusted depending on the air pressure in the intake manifold.
This directly affects the metering of fuel through the barrel as it is moved away from the cover 18. The shape of the plunger shown in Figures 2 and 3 continues as air pressure in the intake manifold increases until the plunger reaches the position shown in Figure 3, allowing maximum fuel to flow through the barrel. Provides a gradual release of increasing amounts of fuel.

As long as the intake air pressure applied to diaphragm 28 and piston 34 remains high enough to maintain main spring 40 in compression and to maintain the plunger in the position shown in FIG. flow into. However, as soon as the intake air pressure begins to drop, the force on the main spring 40 decreases and becomes less than the force required to keep the main spring 40 in a compressed state. The main spring 40 then biases the piston 34 toward the air/fuel control cover 18, ultimately applying a force on the diaphragm 28 equal to that exerted by the intake air pressure and the force of the bias spring 42. As the intake air pressure decreases, the piston 34 is urged further toward the cover 18, moving the plunger 32 toward the cover 18, so that the plunger eventually moves against the undercut 60 as shown in FIG. It is placed in a “no air” condition.

FIG. 4 shows a second embodiment of the barrel and plunger having a different shape from the embodiment of the barrel and plunger shown in FIG. 104 included. However, this plunger embodiment includes a sharp edged angular shoulder 106 in place of the chamfer 90 of the first embodiment. As in the first embodiment, the plunger 100 is placed within the vertical hole 10B of the barrel 100.

Barrel 110 includes fuel inlet ports 112, 118.121 and fuel outlet port 114, each substantially corresponding to passageway 74.76 in FIG. The shape of the barrel 31 near the passage 74 in one embodiment is different. The barrel 110 of the second embodiment has a deep undercut 116 in the area where the barrel contacts the air/fuel control system fuel supply passage 66 (FIG. 2). Furthermore, it is connected to the fuel port 112 or port 118, and is connected to the center arrow 12 in FIG.
As shown at 0, fuel is metered into the central bore 10B of the barrel and exits from the fuel outlet port 114. Fuel port 112 has a larger diameter than port 118 and has a narrow passageway (
(not shown) connects these two passages, so when looking at the barrel 11O from above in the area of the undercut 116:
The fuel inlet ports 112, 118 and the connecting channels have a keyhole-like shape. A separate fuel inlet port 121 is provided to equalize the fuel pressure around the plunger 100.

The position of plunger 100 shown in FIG. 4 substantially corresponds to the position of plunger 32 shown in FIG. This is the position that the plunger occupies when it is moved in a direction away from the air-fuel control bag 18. When the intake air pressure decreases during engine operation, the plunger 100 moves toward the air/fuel control bag 18 and the port 11
8 with the stopper portion 104 of the plunger. Conversely, as increasing air pressure moves the plunger out of contact with port 118, shoulder 106 gradually opens port 11B,
Gradually increasing amounts of fuel are allowed to exit through the barrel center hole 108 and into the outlet port 114.

Similar to the barrel and plunger embodiments shown in FIGS. 2 and 3, the plunger 100 and barrel 110 of FIG. The clearance between is 0.00007
5-0.000125 inches (about 0.00020-0.
00032cm). As mentioned above, leakage of fuel from the barrel is thereby minimized in practice.

The barrel and plunger assembly of the present invention is designed to minimize fuel leakage around the plunger and barrel. This is accomplished by controlling the pressure differential between the second chamber 26 and the barrel center bore 33 at the tip 37 of the plunger. Plunger center channel 3
5, by providing an opening 39 and a conduit 122 leading to the housing of the fuel pump, the high pressure of the fuel in the central bore 33 is reduced by the time the fuel reaches the area of the opening 39, and the fuel flows into the second chamber 26. is further reduced by the time it reaches . Thus, leakage of fuel into the second chamber is substantially eliminated and excess fuel escapes via opening 39 and is returned to the fuel pump via conduit 122. Unlike conventional air-fuel control devices, the air-fuel control device of the present invention controls the pressure difference between the opening 39 and the second chamber 26.
to maintain almost no fuel.

As mentioned above, providing the barrel and plunger assembly with a high precision fit significantly minimizes fuel leakage;
A drain is necessary to ensure that any excess fuel that may be present is removed. However, the unair-fueled control system does not require an extensive external drain system as in conventional air-fueled control systems. The very small amount of fuel that may leak through the plunger escapes through an internal passage of the fuel pump to the engine crankcase, rather than through such a drain system. FIG. 5 shows a cross-sectional view of the air/fuel controller housing 20, illustrating one possible drain line for excess fuel without including the air/fuel control mechanism. As can be seen in FIG. 5, control chamber 22 is fluidly connected to barrel cavity 23. Past the plunger, in particular the control chamber 22 of the barrel, i.e. the second chamber 2
Fuel leaking near the end of the barrel on the side closer to the inside 6 collects in the second chamber 26. Therefore, the drain line 130
If provided, it serves as a fluid path for excess fuel to flow from the air/fuel ff controller to another conduit in the fuel pump (not shown) and thence to the engine crankcase. Such a drain conduit may be located, for example, in the fuel pump cover (not shown).

As a comparison of the air/fuel control housing (FIG. 5) and the air/fuel control mechanism located within the housing (FIG. 2) shows, the present invention can be incorporated into an air/fuel control housing such as a fuel pump. and a plurality of individual components to be inserted;
As such, the present invention is ideally suited for retrofit implementation into existing fuel pumps that include similar housings or holes for air/fuel control devices within the fuel pump. Appropriate shims, retaining rings, seals, etc. may be used as necessary for proper installation of the air/fuel control system. Furthermore, since the outer dimensions of the barrel part of this air-fuel control device almost correspond to many existing air-fuel control devices, both barrels and one of the plunger assemblies in Book 9 and Akira can be replaced to It is possible to provide substantially leak-free and effective metering of fuel depending on manifold pressure.

[Effects of the Invention] The air-fuel control device of the present invention is mainly used in compression ignition internal combustion engines in which fuel is supplied to the engine according to the air pressure within the intake manifold.

The present air/fuel control system is particularly useful for carefully and precisely controlling the flow of fuel into the engine cylinders depending on engine operating conditions. In addition, this air-fuel control device provides a controlled amount of fuel from the fuel pump in response to the increasing air pressure in the intake manifold, and provides a controlled amount of fuel from the fuel pump in response to the decreasing air pressure in the intake manifold. It can be effectively used both to gradually reduce the flow of water. Furthermore, the air-fuel control system of the present invention is ideally suited both for first-time installation in a new engine and for replacement implementation in an existing engine.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a perspective view of a part of the engine fuel supply system,
2 shows an air-fuel control device for regulating fuel flow to the engine in response to air pressure in the engine's intake manifold;
The figure is a sectional view taken along line 2-2 of the air-fuel control device shown in Figure 1, with the cover rotated 90''counterclockwise;
FIG. 3 shows a cross-sectional view of a first embodiment of the barrel and plunger assembly of the air-fuel control device; FIG. 4 shows a cross-sectional view of a second embodiment of the barrel and plunger assembly of the air-fuel control device; and FIG. 5 is a front cross-sectional view of the internal combustion engine fuel pump taken along line 5-5&1 of FIG. 1, showing the position of the air-fuel control device relative to the fuel pump. 10-... Air fuel control device 16... Air supply section (air line) 18... Cover, 20-... Housing 24
．． 26... 1st and 2nd chambers, 28... Bellows member 30
・・・Fuel metering supply means (stem valve) 31.110-・
・Barrel 32.100... Plunger 33.108... Barrel hollow interior (center hole) 34...
・Piston 35.39, 122...Pressure adjustment means (35: channel, 39: opening) 40.42...1.2 spring 44...iJJ adjustable spring holding means 48...adjustment Means, si-...Cap means 54...Cover center recess 60.116...Cavity extension means (blender cut) 70.72. 112.114.118...Port means 74.76.
...Fuel supply inlet 88.102...Stem means 90...Fuel control means (chamfering means) 92.104.
...Stopper means 106...Shoulder means, 130-...Drain means agent Patent attorney Yoshiyuki Inaba FIG, I FIG, 3゜

Claims (27)

[Claims] (1) A fuel supply system for an internal combustion engine having an intake manifold whose operation is controlled by the pressure of fuel supplied to the engine from a fuel source and which supplies air to the engine, the system comprising: (a) responsive to air pressure within the intake manifold; a pneumatically responsive means for mechanically regulating the flow of fuel toward an engine, comprising: (a) first and second chambers, the first chamber including means for fluid communication with an engine air supply; , the second chamber being sealed from fluid communication with the fuel supply system; (b) disposed within each of the chambers to convert changes in intake manifold pressure into mechanical movements to (b) pressure regulating means for controlling the flow of fuel from said fuel supply system in response to changes in direct intake manifold pressure; A fuel supply system comprising: fuel metering means for substantially eliminating fuel leakage from the supply system. (2) the pressure-responsive actuating means includes a flexible bellows member separating the first and second chambers; and a flexible bellows member located within the first chamber urging the bellows member toward the second chamber. 1 spring means located within the second chamber to support the first bellows member;
second spring means biased toward the chamber, and wherein the fuel metering means is movably connected to the pressure-responsive actuating means in response to changes in air pressure within the first chamber. The fuel supply system according to item 1. (3) said fuel metering means includes barrel means providing a connection between said fuel source and said fuel supply system; and plunger means fitted within said barrel means for controlling the flow of fuel from said fuel supply system. The fuel supply system according to claim 2, comprising: 4. The fuel supply system of claim 3, wherein the clearance between said barrel means and said plunger means does not exceed 0.000075 to 0.000125 inches (approximately 0.00020 to 0.00032 cm). (5) the barrel means comprises a generally cylindrical barrel having a hollow interior located along a longitudinal axis generally perpendicular to the flexible bellows member, and further for directing fuel into and out of the interior of the barrel; 4. A fuel supply system as claimed in claim 3 including a fuel supply inlet passageway and a fuel supply outlet passageway respectively directed to a fuel supply inlet passage and a fuel supply outlet passageway. (6) stem means for connecting the front plunger means to the pressure-responsive actuation means, stopper means for blocking the flow of fuel through the fuel supply inlet passage, and located between the stem means and the stopper means; 6. A fuel supply system according to claim 5, further comprising fuel control means for controllably introducing fuel into said barrel. 7. The fuel delivery system of claim 6, wherein said pressure responsive actuation means moves said plunger means along the longitudinal axis of said barrel in a direction directly responsive to air pressure within an intake manifold. (8) when the air pressure in the intake manifold is zero, the pressure responsive actuation means moves the plunger means to position the stopper means in a position that substantially blocks the flow of fuel through the fuel supply inlet passage; When the air pressure is at its maximum rated level, the pressure-responsive actuating means moves the plunger means to place the fuel control means in a position that allows the maximum amount of fuel to flow through the fuel supply inlet passageway. The fuel supply system according to claim 7. (9) said barrel interior includes a cavity extension means for receiving fuel from said fuel supply inlet passage having a diameter greater than said barrel interior; and said stop means of said plunger means has a diameter greater than said stem means; 9. The fuel supply system of claim 8, wherein the fuel control means of said plunger means includes chamfer means for providing a gradual change in plunger diameter between said stem means and said stopper means. (10) said barrel includes port means for interacting with said fuel metering means to control the amount of fuel flow through the barrel, said stop means having a larger diameter than said stem means; 9. The fuel supply system of claim 8 including angular shoulder means having a diameter substantially equal to the diameter of said stopper means and for controlling the flow of fuel from said port means and said fuel supply inlet passageway. 11. The fuel supply system of claim 2, further comprising fuel drain means for directing excess fuel from the fuel supply system to the engine crankcase. (12) The fuel supply system according to claim 11, wherein the fuel drain means is located completely inside the engine. 13. The fuel supply of claim 6, wherein the distance between the plunger means and the interior of the barrel ranges from about 0.000075 to 0.000125 inches (about 0.00020 to 0.00032 cm). system. (14) An intake manifold whose operation is controlled by the pressure of the fuel supplied to the engine from the fuel source and which supplies air to the engine, and mechanically adjusts the flow of fuel into the engine according to the air pressure within the intake manifold. A plunger and barrel assembly for a fuel supply system for an internal combustion engine, the plunger and barrel assembly having a pneumatic response means for receiving the fuel supply system, and a housing means for receiving the fuel supply system, the plunger and barrel assembly being engaged with the housing means. vertical barrel means providing fluid communication between the fuel source and the engine;
plunger means connected to the pressure responsive means in a coaxial, slidable, precision fit within the central bore of the barrel means for selectively opening and closing the fluid communication in response to air pressure within the intake manifold; and a plunger and barrel assembly, the plunger means including pressure regulating means for substantially eliminating leakage of fuel from the assembly. (15) The pressure regulating means includes conduit means within the plunger means for directing excess fuel therethrough, and opening means providing fluid communication between the conduit means and the barrel means. The plunger and barrel assembly according to item 14. (16) the barrel means includes an internal cavity extension providing fluid communication between the fuel supply and the engine, and the plunger means directs the flow of fuel from the fuel supply through the internal cavity extension of the barrel to the engine; and stop means for blocking the flow of fuel from the fuel supply through the internal cavity extension of the barrel to the engine.
Plunger and barrel assembly as described in section. (17) said chamfer means having a diameter that gradually increases along the longitudinal axis of said plunger means, said stop means substantially equal to a maximum diameter of said chamfer means along the remaining longitudinal axis of said plunger means; 17. The plunger and barrel assembly of claim 16 having a constant diameter. (18) The difference between the diameter of the stopper means and the diameter of the central hole of the barrel means is about 0.000075 to 0.00.
0125 inches (approximately 0.00020 to 0.00032
18. The plunger and barrel assembly according to claim 17, wherein the plunger and barrel assembly is .cm). (19) said barrel means includes port means providing fluid communication between said fuel supply and the engine, said plunger means directing fuel into the barrel center bore through said port means; 15. A plunger and barrel assembly as claimed in claim 14, including stopper means for blocking the flow of fuel through the means and into the barrel center bore. (20) The plunger and barrel assembly according to claim 19, wherein the cross-sectional diameter of the annular shoulder means is substantially equal to the cross-sectional diameter of the stopper means. (21) The difference between the diameter of the stopper means and the diameter of the central hole of the barrel means is about 0.000075 to 0.00.
0125 inches (approximately 0.00020 to 0.00032
21. The plunger and barrel assembly according to claim 20, wherein the plunger and barrel assembly is .cm). (22) It has an intake manifold whose operation is controlled by the pressure of the fuel supplied to the engine from the fuel source and supplies air to the engine, and which is connected to the intake manifold and directs the fuel toward the engine according to the air pressure in the intake manifold. An air-fuel control system for an internal combustion engine including a pneumatic responsive means for mechanically regulating flow, the pneumatic responsive means comprising: (a) a first chamber in fluid communication with the intake manifold;
(b) a second chamber separated from said first chamber by a flexible bellows member secured to said piston; (b) each disposed on each side of said piston and biased in opposite directions to mechanically control changes in intake manifold pressure; a pair of spring means, one of the spring means being located within the first chamber and biased to move the piston in a first direction; the other of the spring means being biased to move the piston in a first direction; (c) movably connected to the piston and biased to move the piston in a second direction opposite the first direction; fuel metering and dispensing means movable between a fuel flow position and a second fuel blocking position, the one spring means being movable between a fuel flow position and a second fuel blocking position, wherein as intake air pressure in the first chamber applied to the bellows member increases, the one spring means is biased in the first direction to move the fuel metering and supplying means to the first position, and as the intake air pressure in the first chamber applied to the bellows member decreases, the other spring means is biased toward the piston. biasing in the second direction to move the fuel metering means to the second position and substantially prevent fuel from flowing through the air/fuel control device; Device. (23) The one spring means includes adjustable spring holding means for controlling the magnitude of longitudinal compression and expansion of the one spring means in the first chamber in response to rising air pressure, 23. The air-fuel control system of claim 22, which controls the amount of air pressure required to bias in the first direction. (24) The air-fuel control device according to claim 23, wherein the spring holding means includes adjustment means located outside the first chamber and engaging the spring holding means at a desired air pressure setting. (25) A claim in which the air-fuel control device includes a cover means fixed to the air-fuel control device to limit the size of the first chamber and fix the bellows member to the air-fuel control device. 25. The air-fuel control device according to item 24. (26) The cover means includes a central recess, the adjustment means is disposed within the central recess, the central recess is located proximate to the engine, and the air/fuel control device is mounted on the engine. 26. The air-fuel control system according to claim 25, wherein access to said adjustment means is blocked when said adjustment means is blocked. (27) The air-fuel control device according to claim 26, wherein a cap means that covers the adjustment means is fitted into the central recess.