JPS5922067B2 - Internal combustion engine fuel injection system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to a body forming an air intake duct and a pump body for directing fuel from an inlet to an outlet adapted to supply one or more fuel injectors. Provided between the pump device and the inlet and outlet of the pump body,
a metering device driven in time relation to the crankshaft or other rotary output member of the engine for delivering a metered amount of fuel toward the outlet for each operating cycle of the engine; A fuel injector for an internal combustion engine (hereinafter referred to as a designated type of fuel injection equipment).

The present invention relates to a specified type of fuel injection device intended for use in an engine having one or more cylinders and an ignition device for igniting the air-fuel mixture in the cylinders by a spark discharge. This was done by

The invention also comprises a metering cylinder comprising a free piston element or a shuttle piston element movable between stops, the distance between said stops being determined by the amount of fuel supplied during each stroke of the free piston. The cylinder spaces on both sides of the piston are connected to the pump and the outlet part respectively through commutator valves during continuous operation, in each case the other valve spaces are connected to the outlet part and It has been developed in conjunction with specified types of fuel injection devices each coupled to a pump.

If the fuel injection system is to be used in a multi-cylinder engine, the outlet section is provided with a plurality of outlets, and the commutator valve is combined with a distribution valve system or made as a distribution valve system, each of which is connected in an appropriate sequence. Supply fuel from the outlet.

A current environmental problem is to avoid or minimize air pollution caused by exhaust gases from internal combustion engines.

To this end, there is an urgent need to accurately control the amount of fuel supplied to the engine during each operating cycle of the engine to ensure complete combustion of the fuel, and for this the mixture ratio is too high. In other words, it is particularly important to avoid situations where the fuel content ratio is so high that complete combustion cannot be achieved.

If one attempts to operate the engine at a certain suitable mixture ratio to achieve this non-polluting condition (this mixture ratio is significantly greater than that normally used in engines using carburetors) , a typical mixing ratio that is desirable to maintain is between 15:1 and 17:1.

It is important not to dilute the air-fuel mixture by increasing the mixing ratio any further.

If not, the engine will misfire and lose power,
Air pollution increases due to the emission of unburned mixture.

The above mixing ratio is the ratio of the weight of air to the weight of fuel.

There are two ways to obtain the required mixing ratio.

One is the mass flow method (as applied to carburetors), which measures the weight of air required by the engine in a given time and calculates the mixture ratio required in the same time. It supplies a weight of fuel that gives .

Measuring the actual weight of air drawn by an engine faces considerable difficulties.

The main problem is obtaining a signal of sufficient magnitude without interfering with the engine's "breathing".

This is because such a signal is extracted by providing a venturi section, or equivalent, in the air intake duct through the carburetor.

The second method is known as the velocity-density method.

This method involves using engine speed to control the amount of air intake and the amount of fuel delivered (1
The amount of air taken in per minute is related to the engine (7) rpm, and the amount of fuel delivered per minute is related to the rpm by driving a fuel metering device in temporal relation to the engine).

Next it is necessary to measure the air density parameter.

This air density can be determined by measuring its pressure and temperature, which measurements are used to further control the fuel delivered.

This method provides more precise control than the mass flow method.

It is an object of the present invention to provide a new and improved fuel injector of the specified type which employs a velocity-density method to detect air pressure and air temperature parameters in an accurate, simple, reliable and economical manner. It is to be.

According to the invention, a single pressure sensing device is provided which is sufficiently isolated from the outside air within the body of the device to detect the absolute pressure in the air intake duct and a temperature response to detect the air temperature in the air intake duct. a device and a mechanism operative between the sensing device and the metering device to control operation of the metering device as a function of absolute pressure and air temperature in the air intake duct, the sensing device having a mechanical output. A specified type of fuel injector is obtained.

The cross-sectional area of the air intake duct surrounding or within the area of the pressure sensing device need not be limited in order to operate the pressure sensing device.

Another feature of the invention is that the temperature sensing device includes an expandable chamber that provides a mechanical output in a mode that is relatively unaffected by ambient mechanical disturbances caused by the air flowing through the air intake duct. .

Furthermore, the pressure sensing device can also include an expandable chamber supported together with the temperature sensing device, said mechanism amplifying the mechanical output of the two chambers.

Thus, one embodiment of the pressure sensing device preferably includes an evacuated container.

The interior of the container has an internal spring tending to inflate it and an external spring device resisting expansion, so that the container deflates in response to a decrease in absolute pressure within the air intake duct.

As will be explained in more detail later, the advantage of this device is that it facilitates setting with high accuracy the ratio between the power (displacement) given by the evacuated vessel and the value of the absolute pressure in the air intake duct. It is to be.

Absolute pressure detection enables calculation of the mixture ratio independently of the external atmospheric pressure, so that vehicles equipped with engines having this device can operate satisfactorily at different altitudes.

Yet another feature of the invention is that the fuel injection system can include a device for admitting a controlled amount of air into the air intake duct in response to engine operating parameters.

In this way, it is possible to increase the engine operating speed even when the engine is cold, for example when started, thereby reducing the risk of the engine stalling during idle operation.

Yet another feature of the invention is a single sensing device (hereinafter referred to as the main pressure sensing device) for sensing the absolute pressure within the air intake duct.
In addition, an auxiliary pressure sensing device can be provided to detect sudden changes in air pressure in the air intake duct, such as when caused by a sudden opening of a throttle valve.

This avoids delays in engine acceleration even when the throttle valve is suddenly opened.

As mentioned above, the present invention includes an air intake duct whose air flow rate is controlled by adjustment of a throttle valve, a high pressure fuel pump that determines the flow rate of fuel from an inlet to an outlet, and one or more air intake ducts connected to said outlet. a metering device that is driven in synchronization with the crankshaft or other rotational output member of the engine and delivers a metered amount of fuel from the outlet for each operating cycle of the engine, and controlling the operation of the metering device; and a detection device for obtaining an appropriate air-fuel ratio in response to air pressure and temperature, wherein the detection device is installed in an air intake duct and is substantially isolated from external atmospheric pressure. It has a pressure detection element 29 for detecting the absolute pressure in the duct and a temperature detection element 76 for detecting the air temperature in the duct. The main feature is that a cam device is connected to the operating detection device, and the cam device is cam-coupled to the metering device, so that the amount of fuel supplied by the metering device can be measured according to the operating state of the internal combustion engine. The main function and effect is that it can always be controlled appropriately depending on the situation.

And the main object of the invention is to provide a carburetor air intake having a cross-sectional area greater than the cross-sectional area of the air intake duct and communicating with the air intake duct at a location downstream of an adjustable throttle valve used in the air intake duct. a passageway, an inlet communicating with the air intake duct and a fuel supply end disposed in relation to the carburetor air intake passage, responsive to a decrease in pressure within the air intake duct below atmospheric pressure; and a fuel jet element for supplying fuel into the passageway, and an air shutoff valve and a fuel shutoff valve movable from an open position to a closed position by fluid pressure generated by a fuel pump device. It is something that can be matched.

As a conventional fuel injection device, US Pat. No. 3625
No. 191 discloses a configuration for detecting the air pressure of an air intake manifold, and Japanese Patent Publication No. 33-3303 describes the idea of detecting air temperature. A device that detects the absolute pressure of the air in the air intake duct is cleverly combined with a temperature-responsive device that detects the air temperature to control the amount of fuel injected.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

A complete system for supplying a fuel, such as petroleum, to an internal combustion engine is shown in FIG.

This device has a fuel tank 10, which is connected by a pipe 11 to a low-pressure fuel pump 13, and via a filter 12 and a pipe 14 to an inlet 14a of a fuel injection device 150.

The fuel injection device 15 is mounted directly on the intake manifold 16 of an internal combustion engine 17 of the type in which fuel ignition is performed by a spark plug.

For example, this engine has six cylinders arranged in a V-shape.

The fuel injection device 15 includes a high-pressure pump 18 whose inlet side is connected to the pipe 14, a metering device including a commutation/distribution valve 19,
It comprises a main unit with a metering unit 20 in the form of a cylinder and a free piston that can move between stops.

The high pressure pump 18 and valve 19 are connected to a belt 22 by an input shaft 21.
is driven through the crankshaft at half the speed of the crankshaft.

The belt 22 is provided with teeth facing inward, and is connected to the shaft 21 and the driven shaft 2.
It is adapted to engage a pulley having three outward facing teeth.

The high pressure fuel from the outlet side of the pump 18 is transferred to the commutation/distribution valve 1
90 commutation port to the metering unit 20;
It is then added back to the distribution port of the valve 19 and into the injectors 26 through respective pipes 27 connected to the outlet of the device body so that the injectors receive pulses of fuel in the required order.

These injectors are mounted in openings in the engine intake manifold 16.

The fuel injection device further comprises a detection or control device 29 which controls the operation of the metering unit 20.

The controller 29 determines the mixture ratio supplied to the engine according to the parameters it detects.

The fuel injector also includes an airflow duct.

Through this duct to the intake manifold 16, air can flow under the control of a manually operated valve, such as a butterfly valve.

The fuel injection system also includes a carburetor 30 that allows engine starting without driving the engine at high starting speeds, as described below.

Furthermore, a blow-off valve 31 is connected to the outlet side of the high-pressure pump 18 in order to return the fuel to the tank 10 through a pipe 32.
is also provided.

Excess fuel, which is approximately twice the maximum demand of the engine, is sucked by the high pressure pump 18 and transferred to the suction valve 31 and the pipe 3.
2 to the tank 10 to cool the high pressure pump and its attached parts.

Referring now to FIG. 2, the main body 33 of the fuel injector has an upper portion 33a forming an elongated chamber housing the high pressure pump 18, a commutation and distribution valve 19, and a metering unit 20.

The lower portion 33b can be formed integrally with the upper portion 33a.
It has a rectangular box shape as a whole, and has three rotating spindles.
A chamber 34 is formed in communication with a passageway 35 extending through a sleeve-like throttle valve member 36 which includes a manually controlled butterfly valve plate 37 secured to the sleeve.

As shown in FIG. 2, the chamber 34 is open in three directions: the front, the rear, and the bottom.

The throttle valve member 36 can be attached to any of these openings, one of the remaining openings being closed by the plate and the other connected to the inlet opening provided by the intake manifold 16. Ru.

With this configuration ° engine throttle I) 7
The mounting force of the fuel injector can be slightly modified to best suit the engine for any given engine, allowing for optimal use of space in the engine compartment to accommodate auxiliary parts such as the air cleaner. do.

The air population of the throttle valve member 36 is designed to accommodate the main components of the detection and control device 29 in order to measure the absolute pressure and temperature parameters of the air entering the chamber 34 and to control the operation of the metering unit 20. A chamber 34 forming part of an air intake duct extending to the open side of the chamber 34 is mounted above the inlet opening of the intake manifold.

The cross-sectional area imparted to the air flow by the chamber 34 around the detection device 29 should be at least equal to, and preferably greater than, the cross-sectional area imparted by the throttle member 36 when the valve plate 3γ is fully opened. do.

The control signal or pressure sensed by the sensing device 29 is therefore taken without imposing air restrictions on the "breathing" of the engine.

Also, because of the location of sensing device 29, device 29 responds instantaneously to pressure changes without the delay that would occur if it were mounted in a separate chamber that is connected to chamber 34 by a pipe.

The body portions 33a and 33b may be made of a light alloy casting, such as an aluminum alloy.

The high-pressure pump 18 is of rotating vane type and includes a rotor 40 mounted between fixed plates 41 and 42 separated by a ring 41a.

The rotor 40 has radial vanes 43 made of carbon.

The rotor 40 is fixed to a drive shaft 21, one end of the shaft 21 is rotatably mounted on a ball bearing 44a, and the other end is rotatably mounted on a flat journal bearing 43b of a fixed plate 42.

Fuel, such as petroleum, passes through inlet 14a to high pressure pump 18.
is placed in the suction side chamber 18a of.

A filter 18b can be attached to the high pressure pump as shown.

Fuel is delivered from the high pressure pump to the space 46 through holes provided in the fixed plate.

Before describing the structure of the metering device, it is convenient to refer to FIG. 5, which diagrammatically shows the overall construction and mode of operation of the metering device.

This metering device includes a metering unit 20 and a commutation/distribution valve 19.
including.

The valve 19 is fixed to the drive shaft 21 and is connected to a rotary valve plate 48.
A rotating assembly is provided which includes a rotating carrier 47 forming a shallow cylindrical recess for receiving.

The plate 48 has a rotary valve plate 49 with a large diameter.
is installed.

The plate 48 has a flat portion on one side that engages a flat portion of the carrier 47 to ensure that the plate 41 drives the facing plates 4B, 49 which are joined by gluing or other means. ing.

The rotary valve plate 49 is pressed against the opposite side of the metering cylinder block 50.

In this cylinder block, a metering cylinder 51 extends across the block as far as the axis of rotation of the rotary valve plate.

Cylinder 51 includes a free piston 52 that can move between stops 54 and 55.

The metering cylinder block 50 has sump outlets g1 to g6 which are connected to pipes 27 leading to the injectors 26, respectively.

These outlets are connected to ports f1-f6 by passages extending axially inside the block.

These ports are successively crossed by ports) d of the rotary valve plate 49, thereby acting as a distributor.

The block 50 is connected to the upper and lower spaces 81 and 82 of the piston 52 by passages 51at51b, respectively.
The functions of port) el and e2 are the port c of plate 49.
1 to c6 and ports bLb3. of the plate 48. b5 in combination with a T-shaped surface passage formed in the left side surface of the plate 48.

The T-shaped surface passage does not penetrate through the thickness of the plate 48;
Each time ports f1-f6 are crossed by port d,
Branch b22b4 as a commutation member that allows the piston 52 to make one stroke from the upper limit to the lower limit or vice versa
tb6, thereby supplying a metered amount of fuel to the outlets g1-g6.

Solid arrow 56 indicates the flow of fuel into the upper cylinder space s1 of cylinder 51 during piston 520 stroke.

This flow starts from the lower cylinder space s2 with the dashed line arrow 5γ
Push out the fuel as shown in and transfer the fuel to the outlet side g6.
It is effective to supply from

Fuel from high pressure pump 18 is supplied to port a1. bl.

It is clear that the cylinder space s1 is reached through cl, el.

Fuel from cylinder space s2 is transferred to port e2. c2,
Rim b4. b6, po) d, f6. Pass through g6.

If the drive shaft is rotated 60 degrees (which corresponds to a 120 degree rotation of the engine crankshaft), the fuel from the high pressure pump will flow through ports 1-a5. b5. c5 (now in its lowest position), e2 to reach cylinder space s2.

The fuel in space s1 is po) el, c2, rim b2 (
(at the highest position at that time), rim b6, port d, is,
g5.

This position is shown in FIG. Similarly, after the next 60 degree rotation, another fluid passage is formed to move the piston 52 in the opposite direction and provide a metered amount of fuel from the next outlet g4.

Hereinafter, in this manner, in this embodiment, a fixed amount of fuel is supplied from a different outlet every 60 degrees of rotation of the drive shaft.

In other words, when high-pressure fuel is supplied to the cylinder space s1, the other cylinder space S2 is already filled with fuel.

Then, by supplying high pressure fuel to sl, the free piston 5
2 is pushed in, the fuel filled in s2 flows from the outlet port through the pipe 27 to the respective injector 2.
Sent to 6.

Next, in the opposite situation, high-pressure fuel is supplied to s2, and when the free piston 52 is pushed in the opposite direction, the fuel already filled in s1 is
From the outlet port it is sent via pipe 27 to the respective injector 26.

In this way, when one of S1 and S2 is supplied with high pressure fuel, the other is already filled with fuel, and this is done alternately at 81 and 82.

By reciprocating the free piston 52, an appropriate amount of fuel is supplied to the cylinder according to its stroke.

A spring 58 acting between the bottom of the recess in the carrier plate 47 and the small diameter rotating plate 48 forces the 7" L/-ts 48 and 49 into contact with the face of the metering cylinder block 50.

At least plate 49 is made of a material that provides good sealing properties to the cylinder block 500 face and a suitably long life.

In practice, plates 48 and 49 can be made of carbon and cylinder block 50 can be made of steel.

In order to control the free piston 520 stroke, the sensing device 29 senses certain selected parameters, namely the absolute pressure and temperature of the air in the air intake duct downstream of the throttle valve 37, i.e. in the chamber 34.

The absolute pressure is detected by a single device, preferably in the form of an evacuated container, preferably a bellows 60 as shown.

This bellows has a corrugated side wall 61 that can be expanded and contracted in the axial direction,
(end play) 62, 63.

The plates are pushed apart from each other by a preloading device, such as a helical compression spring.

Bellows installed in the air intake duct are subject to the absolute pressure of the air attempting to enter the intake manifold (unlike those in chambers that are connected to the air intake duct by relatively small diameter pipes). .

The bellows end plate 62 is secured to a generally frustoconical cam element 65.

Cam element 650 truncated conical surface 66 is eccentric with respect to axis 67,
The cam element 65 and the bellows can rotate about this axis.

For this purpose the cam element is mounted on a hollow spindle 69.

The through hole of this spindle communicates with the outside air with an air population of 10.

the spindle and the cam element form an air intake valve arrangement;
It has slots 69a and 65a extending in the axial direction.

When the engine is cold, these slots overlap, allowing a controlled amount of air to be admitted to provide a rapid idle link.

When the engine temperature rises, the cam 65 rotates as will be described later, moving the slots from their circumferential overlap.
Close the valve.

Another end plate 63 of the bellows is attached to the lower port of the body.
It is movable axially within a cylindrical chamber 73 formed by 33b.

It is rotatably mounted in a well-sealed bearing 71 inside an accelerating piston 72.

The plate 63 itself is attached to the sleeve T4.

This sleeve forms the output element of the summing mechanism 75 and outputs the air temperature in the chamber 34 as detected by an element 76 and another selected temperature, such as a temperature parameter related to the engine temperature, as detected by an element 77. Add together.

As will be described later, the outputs of these two sensing elements 76 and 77 are transmitted to the sleeve 74 as rotation, and since the end plate 63 of the bellows is fixed to the sleeve 74 in terms of rotation, the bellows and the cam element 65 are Rotated to adjust the position of the lower stop 54 via the tappet (78) carrying rollers 79.

End plate 62 and cam element are also moved axially in response to pressure changes within chamber 34.

Therefore, the position of the lower stop 54 is determined by all sensing parameters combined.

The bellows tends to be expanded by an internal spring 64 which counteracts a spring 80 provided within the spindle 69.

It is required that the value of the ratio between the axial movement distance of the cam element 65 and the absolute pressure in the chamber 34 be maintained with high accuracy.

Since the bellows wall 61 has some elasticity and the inside of the bellows is evacuated, it cannot be easily changed or adjusted after the spring 64 is inserted into the bellows.
Selection of the effective spring modulus produced by the combination of springs 64 and 80 is accomplished by selecting spring 80.

The temperature sensing elements 76,77 may be in the form of wax capsules commonly used in engine cooling systems to control fluid flow.

Each element contains a material, e.g. It consists of a chamber that can expand in different directions.

Capsule 76 has a mount supported inside sleeve 74 , and capsule 77 has a mount supported inside housing 82 .

Opposite end surfaces of the capsule forming the output portion contact both ends of the summing mechanism 750.

The addition mechanism algebraically adds the outputs of the capsules 76 and 770, and consists of two sleeves 8 inserted into each other in the axial direction.
It has 3.84.

Each sleeve has two opposing slots at opposite ends of its diameter.

These slots extend over a quarter of the circumference of the sleeve, leaving a pair of axially extending partially cylindrical arms 83a, 84a, etc.

Since the arms of one sleeve are slidably fitted axially into the slots of the other sleeve, the two sleeves can move relative to each other axially, but alternately
It is a driving relationship.

The sleeve 83, which can be moved in the axial direction by the detection element γ6, has a helical groove 85.

This slot engages a pin 86 fixed to output sleeve 74 and projecting radially inwardly.

Sleeve 84 also has a helical groove 87 which is engaged by a pin 88 which is fixed to housing 82 and projects radially inwardly therefrom.

The two sleeves 83 and 84 are helical compression springs 89
Since the sleeves are pushed apart from each other by the sleeves, each sleeve is brought into contact with the output part of the respective temperature sensing element 76.7.gamma., as the case may be.

Axial movement of either sleeve 83, 840 caused by expansion of the associated temperature sensing element increases the degree of rotation of that sleeve.

This increment is added to rotate the output sleeve 14.

This rotation is transmitted as displacement of the stop 54 as described above.

The angle of the housing 82 can be adjusted around the axis γ0 by loosening the clamp ring 82a.

This adjustment is transmitted to the cam 65 via the pin 88 and the addition mechanism 15.

Housing 82 is rotatable relative to chamber 91;
It is sealed to the chamber by a sealing ring 91a.

The temperature parameter applied to the sensing element 7T can be the temperature of the engine coolant.

In this case it is advantageous to circulate it through the cavity 90 of the chamber 91.

Alternatively, the outer chamber 91 forming part of this cavity may be removed and a heat dissipating fin may be attached to the outside of the housing 82.
The temperature of the compartment where the engine is installed can be shared.

Next, the acceleration piston 72 will be explained.

This accelerating piston is pushed to the left by a compression spring 89 acting via the sleeve 83, the sensing element 76 and the sleeve 74.

Above the sleeve 74 are the end plate 63 and the sleeve 74.
A sealed bearing T1 is fixed in the axial direction between the shoulder portion of the bearing T1 and the shoulder portion of the bearing T1.

If the throttle valve is suddenly opened and the absolute pressure in the chamber 34 suddenly changes, the piston 72, which received the previous absolute pressure when in the right position, is moved to the right and the cam 6
5 in the axial direction and move the stop 54 downward,
Instantly enriches the mixture.

Piston 12 slowly returns to its original position under the action of spring 890 at a rate determined by the leakage of air through piston 72 and through bearing 71 which is not completely sealed.

In such a movement of the accelerating piston 12, the sleeve 74, the detection element 16, and the sleeve 83 move together, so the rotation of the sleeve 74 does not occur. It should be noted that, because of this, the response to changes in air temperature within the chamber 34 is somewhat delayed.

However, while the change in air temperature is a long-term fluctuation, the change in air pressure is rapid and occurs over a short period of time as shown by the degree of opening of the plate 37 and the change in engine speed. is not as severe as the delay in response to pressure changes.

The temperature sensing device - is constructed and mounted to provide a stable mechanical output independent of its surrounding conditions.

For example, the mode of mechanical output, ie, the axial movement of the sensing element or end wall of the capsule 16, is not perturbed by engine vibrations or airflow moving within the chamber 34.

The pressure of the fuel supplied from the high pressure pump 18 is approximately 8.5
About Kg/crtt (approx. 120psi)! However,
It is not generated at the starting speed obtained by the operation of a normal starting motor connected to the engine.

Therefore, the fuel injection device of the present invention includes a carburetor device 30 that operates only during startup.

It is necessary to prevent a double supply of fuel in both the carburetor and the injector of a fuel injector, thus removing fuel from the carburetor while injecting fuel from the fuel injector outlet. To prevent supply, a control signal is applied to the vaporizer that disables its operation.

One convenient signal that can be used for this purpose is a fluid pressure signal taken from the output side of a high pressure pump.

Figures 3 and 4 show this carburetor in detail.

The carburetor includes a carburetor hole 100 (FIG. 3) formed in the body 33 of the fuel injector.

The carburetor hole is provided between the drive shaft and the bellows along an axis parallel to the drive shaft and the bellows.

The wall of the body 33 forms the boundary between the chamber 34 and the chamber in which the metering cylinder block, the commutation and distribution valve arrangement and the high-pressure pump are housed.

The hole 100 of the vaporizer has a large diameter portion 101 (Fig. 3,
4) and a small diameter portion 102.

Within portion 102 is one element 1 of the jet assembly.
03 is slidably attached.

The element has an inner tube 104 in which is provided an axially extending fuel passage 105 terminating in an enlarged diameter end 106 containing a limit valve.

The limit valve includes a valve seat 10γ, a ball 108 and a helical spring 109 that presses the ball against the valve seat 107.

A hole 110 is provided in the end face of the valve seat, through which liquid fuel can pass into an annular space 111 .

The annular space 111 has an inlet 1 of the main body of the fuel injection device.
Fuel is supplied through a passage 13b connected to 4a.

The strength of the spring 109 is selected to open the threshold valve at a constant pressure, such as about 0.2 KV/crA (about 2 psi), which is higher than the gravity of the fuel at the valve but lower than the fuel injection pressure. be done.

This pressure is generated by the low pressure fuel pump 13 in °C.

1-Thus, the valve prevents fuel from flowing through the carburetor due to gravity when the engine and fuel injectors are not operating.

Valve element 103 also includes a head 113 that is closely fitted within the reduced diameter portion 102 of the vaporizer bore.

A sealing ring 114 is attached to this valve element.

This sealing ring 114 is mounted in the groove and seals the annular space 111 from the rest of the vaporizer bore.

The jet assembly includes a jet element 115 in the form of an outer tube that fits into the inner tube 104 like a telescopic tube.

- At a position near the free end of the inner tube 104 in the wall of the second jet element, holes 116 constituting jet exits are provided at both ends of the diameters J and -C.

The carburetor is equipped with two valves: a fuel cutoff valve and an air cutoff valve.

These valves are equipped with plungers 117.

This plunger can be actuated by a piston 117a and can be moved axially within the large diameter portion 101 of the carburetor bore between an open position and a closed position shown in FIG.

In this closed position, the inner end of plunger 117 is 2. It overlaps the mouth or opening of the air passage 101b, which traverses the large diameter section 101 near the free or supply end of the inner tube 104.

Pipe 101 that can be connected to an air cleaner (not shown)
Air is supplied to the air passage 101b by a.

It communicates with the vaporizer bore and the chamber 34 via the air passage 101b.

The fuel cutoff valve further includes a resilient valve element 118 located at the bottom of the bore 119 of the plunger 117.

The hole 119 is continuous with the inner surface of the outer tube 115 of the jet assembly.

Plunger 117 is urged by a helical compression spring 120 acting between head 113 and plunger 11γ to hold plunger 117 in a position where both the fuel cutoff valve and the air cutoff valve are open.

The plunger 117 is inserted into the hole 123 from the outlet of the high pressure pump 18.
, 122 and space 131 to space 121,
When pressurized fuel is delivered, it is activated to close the two shutoff valves.

Space 131 communicates with the outlet side of the high-pressure pump via hole 131a (FIG. 4).

Hole 123 is formed in an inlet plug device 125 that is screwed into the end that is threaded into the inner surface of the carburetor hole, and a sealing ring 125a is fitted within the inner circumferential recess of the inlet plug device.

The hole 123 is formed by a restriction bushing 1 in which a restriction passage 127 is formed.
26, which can limit the rate of supply of pressurized fuel admitted into the space 121 and thus determine the length of the start-up period during which the carburetor remains operational.

This start-up period ends when, under the influence of the injection pressure of the fuel in the space 121, the fuel cutoff valve and the air cutoff valve are closed.

When the throttle valve of the fuel injector is closed or slightly open, the pressure in the air inlet duct downstream of this throttle valve is low, and the cross-sectional area of the pipe 101a and the passage 101b is reduced by the throttle valve member 35. and the cross-sectional area of the main air inlet duct of the chamber 34, air is drawn through the vaporizer air inlet pipe 101a.

The velocity of this air is faster than the velocity of the air flow caused by the opening of the throttle valve plate 36.

The fuel entering the outer tube 115 from the outlet end of the inner tube 104 through the bore 116 of the outer tube 115 is thus atomized as in a conventional carburetor slow jet assembly.
The carburetor is connected to the air inlet duct chamber 34 of the fuel injector.
is carried through a passageway 101b connected to.

The carburetor supplies fuel to the engine even in the event of a failure of the high-pressure pump that prevents the pressure at the outlet side of the high-pressure pump from reaching a value that supplies fuel from the outlet side of the fuel pump to the injectors. be able to.

Therefore, plunger 117 remains in the position shown in FIG.

To operate in this state, the throttle valve 36 is opened only slightly.

Pressure control and relief of the fuel supplied from the outlet side of the high-pressure fuel pump is regulated by a blow-off valve 31.

This outlet valve has a conical valve head 128.

This valve head is mated to the valve seat of the body 129.

The valve head 128 is pressed against the valve seat by a helical compression spring 130.

High pressure fuel is supplied to chamber 131 through hole 131a.

From this chamber fuel is passed through a filter 133 to an inner bore 134 in the body 129 of the blow-off valve.

The bleed valve 31 opens at a pressure determined by the compression spring 130 and releases excess fuel through the bleed valve bore portion 135 towards the passage 136 .

Passage 136 communicates with annular space 111 from which excess fuel is returned to the fuel tank through outlet member 112.

In this way, the flow rate of fuel supplied to the engine from the high-pressure fuel pump is always regulated to an appropriate amount.

The present invention has been described above in detail with reference to Examples, and the main embodiments of the present invention will be described below.

(1) The air and fuel shutoff valve comprises a plunger 11γ carrying a sealing member 118 movable along the mouth of the carburetor air inlet passage 101b and engaging the delivery end of the jet element 104. Fuel injection devices as described in the scope of.

(2) Fuel feed passage 105°10 of jet element 104
6 includes a limit valve 108 which is biased to a normally closed position and opens at a limit pressure greater than the gravitational pressure of the fuel in the jet element 104 but less than the injection pressure from the high pressure pump 18. A fuel injection device according to the claims.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing the main parts of a fuel supply system equipped with the fuel injection device of the present invention, FIG. 2 is a sectional view showing the structure of an embodiment of the fuel injection device of the present invention, and FIG. 2 is a cross-sectional view taken along the line AA in FIG. 2; FIG. 3 is a cross-sectional view taken along the line 3-3 in FIG. 2 showing a carburetor used in the fuel injection device of the present invention; FIG. 4 is a sectional view taken along line 4-4 in FIG. 2, and FIG. 5 shows the overall configuration and operation of the metering device, which includes a metering piston, cylinder unit, and commutation/distribution valve device. FIG. 13...Low pressure pump, 15...Fuel injection device, 17...Engine, 18...
High pressure pump, 20...Measuring unit, 26...
...Fuel injector, 37...Throttle valve,
34...Chamber, 51...Measuring cylinder, 52...Free piston, 12...
...Acceleration piston, 76.77...Temperature detection element, 78...Pressure detection element.

Claims (1)

[Claims] 1 an air intake duct whose air flow rate is controlled by adjustment of a throttle valve; a high-pressure fuel pump that determines the flow rate of fuel from the inlet to the outlet; and one or more injectors connected to said outlet; A metering device that is driven in synchronization with the crankshaft or other rotational output member and delivers a metered amount of fuel from the outlet for each operating cycle of the engine, and a metering device that controls the operation of the metering device and is responsive to air pressure and temperature. and a sensing device for obtaining a suitable air-fuel ratio, the sensing device being located in an air intake duct and substantially isolated from external atmospheric pressure; It has a pressure detection element 29 that detects the absolute pressure in the duct and a temperature detection element 76 that detects the air temperature in the duct, and the detection device is actuated in the axial direction by the detected pressure and temperature. A fuel injection device for an internal combustion engine, characterized in that the cam device is coupled to the metering device.