JP2652850B2 - Fuel metering method and apparatus - Google Patents

Description

The present invention relates to the metering of fuel to an engine, especially in applications where fuel is injected directly into the combustion chamber of the engine.

Fuel metering methods have previously been proposed in which the metered amount of fuel is displaced from the variable volume chamber by the introduction of a gas such as air at a suitable pressure. It is believed that the gas charge contributes at least partially significantly to the useful fuel of the fuel due to improved fuel atomization.

Applicant's International Patent Application No. PCT / AU85 / 00176 and U.S. Patent Application No. 849501 derived therefrom provide for a continuous supply of fuel under pressure with a closed port having a delivery port that can be selectively opened. An improved method of metering fuel to the engine, which is provided to a fixed fixed volume chamber, has been proposed. Gas is periodically admitted to the chamber to maintain a pressure no greater than the fuel pressure in the chamber, and the delivery port is opened during gas entry into the chamber, thereby opening the delivery port and opening the delivery port with fuel and fuel therein. Fuel entering the chamber during the period is delivered from the delivery port to the engine. While this fuel metering and delivery method is effective, it is particularly expensive during manufacturing due in part to the need to operate the exhaust port and the valve that controls the supply of gas to the chamber at substantially the same time. It raises some difficulties in the commercial production of volumes.

It is an object of the present invention to provide an improved delivery of a metered amount of fuel to an engine that is effective and accurate in operation, convenient for manufacture and maintenance, and assists in promoting a high degree of atomization of the fuel. To provide a method and apparatus.

With this purpose in mind, a fuel delivery port and two spaced apart in the direction of flow through the port to communicate with the engine through the port when open and when the port is closed. A valve element selectively openable to define a cavity and provide a sealable engagement between the two locations and between the locations, the method comprising: To the port independently at respective pressures, wherein one of fuel and gas is supplied to the cavity and the other is supplied upstream of both sealable engagement positions, and the valve element is cycled. By opening the port and communicating the port with the engine, the fuel entrained in the gas is delivered to the engine, and the differential pressure between the fuel and the gas in the cavity is adjusted to regulate the fuel flowing into the gas in the cavity. A method consisting of controlling the flow rate Subjected to.

When the port is in communication with the engine, the gas establishes a pressure at the port that is less than the fuel pressure, such that fuel flows into the gas as the gas passes through the port. Therefore,
To control the amount of fuel metered into the gas, the pressure difference between the gas pressure at the port and the fuel supply pressure may be changed. Alternatively, control of the amount of fuel delivered can be provided by maintaining the pressure difference constant and varying the duration while the port is open.

Rapid changes in fuel demand can be adjusted by changing the period during which the port is open, and more gradual changes in fuel supply are adjusted by changing the pressure difference between fuel and gas. To change the pressure difference, the fuel supply pressure and / or the gas supply pressure may be changed. When the fuel is liquid, it is more convenient to regulate the fuel pressure and keep the gas pressure substantially constant.

The fuel supply pressure is conveniently controlled by a regulator responsive to the fuel demand of the engine. The regulator can be electrically operated while controlling a current that is electronically determined from sensing several engine load condition parameters.

In many engines and in single engine applications, it is desirable to change the pattern of fuel distribution in the combustion chamber as engine operating conditions change. This is especially so when trying to achieve the required fuel economy and / or emission control.

Since fuel is delivered to the gas in the port for delivery to the engine, control of the location or timing of delivery of fuel to the gas can achieve control of the fuel distribution within the combustion range of the engine. it can.

Fuel can be introduced into the gas stream at more than one location of the port. The location can be selected to affect the fuel spray pattern as the fuel exits the port. Alternatively or additionally, the timing of fuel delivery to each location and / or the fuel flow rate at each location can be controlled at various rates to affect the spray pattern. Further, the fuel flow at one or more locations can be varied depending on the selected engine operating conditions.

According to a preferred embodiment of the present invention, fuel and gas are independently supplied at respective pressures to a port selectively connectable to an engine combustion charge, said port being in periodic communication with the engine combustion charge, Allowing fuel and gas to flow from the port to the combustion charge with the fuel entrained in the gas, and controlling the location and / or rate at which fuel enters the gas while the port is in communication with the combustion charge; The amount of fuel delivered to the engine per cycle by adjusting the fuel distribution pattern of the charge and adjusting the pressure differential between the fuel and gas supply and / or the communication period between the port and the combustion charge according to the engine load A method for delivering fuel to an engine, comprising:

It will be appreciated that if the fuel pressure at the port is greater than or equal to the gas pressure at the point of entry of fuel into the port, fuel will only flow to the gas at the port. This pressure difference is initially
Obtained from adjusting the respective fuel and gas pressures to establish a basic pressure difference, and vary the fuel or gas pressures according to changes in engine fuel demand to obtain the required changes in fuel supply Obtained from that. The physical arrangement of the ports and associated valves affects the actual pressure state of the gas stream where the fuel is introduced into the gas stream, but these are the factors of the pressure regulator that controls the fuel and gas pressure. This will be explained in the calibration.

It will be appreciated that in adjusting the gas and fuel pressures, respectively, to effect fuel metering, the actual differential pressure at the point where the fuel enters the gas stream is a controlling factor in fuel metering. However, several factors, especially spatial constraints, prevent control of the regulator located very close to the point where fuel enters the gas in the cavity formed in the port.
When the regulator is moved away from the point at which fuel enters the gas, appropriate flow areas in the passages carrying fuel and gas to the cavity are appropriate, respectively, to ensure that changes in regulator pressure are accurately reflected in the cavity. It becomes necessary. It is therefore desirable to have relatively small fixed orifices in the fuel and gas passages very close to the cavity, and that the passages upstream of the orifices have sufficient area to minimize the pressure drop along them. With such an orifice close to the cavity at the port, the sensitivity of the regulator to gas and fuel pressure changes can achieve the three required accuracy in dispensing fuel.

Conveniently, a plurality of fuel orifices are provided to deliver fuel to the cavity at a selected area of the port, thereby obtaining a desired fuel distribution for the fuel charge. Fuel preferably exits from a plurality of fuel orifices arranged in a circle around the axis of the annular gas orifice. The number and location of the fuel orifices from which fuel exits can be varied according to predetermined engine operating conditions, thus affecting the shape of the fuel spray exiting the port and thus controlling the fuel distribution of the engine's combustion charge.

In order to achieve efficient combustion and emission control, it is desirable to ensure that an easily ignitable fuel-air mixture is established at the ignition point, especially under low load engine operating conditions. To control the change in the number of active fuel orifices to achieve the required fuel-air ratio at the ignition point, a greater percentage of fuel per delivery is charged to the combustion charge near the ignition point. You can turn to It is advantageous to deliver all the fuel under low engine load conditions to the combustion charge near the ignition point at the time of ignition.

According to the present invention, there is also provided a device for metering fuel to the engine, the device comprising a fuel supply means and a gas supply means, each means for delivering to the same delivery port, and an in-use port connected to the engine. A valve element operable to selectively open the port for communication with the port, the port and the valve element being spaced apart in the direction of flow through the port when the valve is closed. And a cavity is defined between the positions, at least one of a fuel supply means and a gas supply means communicates with the cavity, and the gas supply means is connected to the two sealing members. Means for opening the port by periodically activating a valve element for delivering fuel entrained in the gas to the engine through the port upstream of the mating position; and Fuel flow And means for adjusting the pressure difference between the fuel supply and gas supply of the cavity to control.

Several fuel ports can be provided, each supplying fuel to the cavity. The location of the fuel port is selected to give the desired fuel distribution to the spray pattern of the fuel-gas mixture exiting the delivery port. Means may be provided for selectively controlling the timing and / or fuel flow from one or more fuel ports, and thus the spray pattern may be varied depending on engine operating conditions.

The proportion of fuel supplied to the port when the port is open is controlled by means operable in response to the engine load to regulate the difference between the pressure of gas and fuel supplied to the cavity. It is convenient.

A plurality of fuel orifices can be provided in communication with the cavity. Fuel orifices can be distributed along the length of the cavity to achieve a desired fuel distribution to the combustion charge as the fuel-gas mixture is delivered. Means are provided for distributing the fuel orifices substantially uniformly, wherein the flow through at least some of the fuel orifices is selectively terminated to control the fuel distribution.

The provision of two spaced sealing engagement positions between the port and the valve element and the communication of the port with the fuel and gas supply at a location separated by one of the sealing engagement positions provides a single unit. A valve element can control the introduction of fuel into the gas and the resulting delivery of the fuel-gas mixture to the engine. Thereby, the structure of the fuel metering device is simplified, and the control of the fuel supply rate is accurately achieved.

The cavity is in an annular shape provided by a circumferential groove in the sealing surface of the port, forming an annular sealing surface on both sides of the groove, with the orifice in the base of the groove. This arrangement results in the sealing surface of the valve element not contacting the edge of the orifice when the valve element is in the closed position. This improves the sealing efficiency and the useful life of the seal between the valve element and the port.

The present invention will be more readily understood from the following description, taken in conjunction with the accompanying drawings, of one actual arrangement of a fuel metering device and its method of operation.

FIG. 1 is a schematic diagram of a fuel supply system embodying the present invention.

FIG. 2 is a partially exploded sectional view of the measuring unit.

FIG. 3 is an enlarged sectional view of a delivery port and a valve portion of the metering unit shown in FIG.

FIG. 4 shows the third of the modified ports and valves.
It is a figure similar to a figure.

Referring now to FIG. 1, metering device 10 has a stem (chamber) 11 having a central air passage 13 and two fuel passages 8 and 9. Communicating with the fuel passages 8 and 9 is a fuel supply conduit 12 that receives fuel from a fuel pump 14 that draws fuel from a fuel reservoir 15. The pressure of the fuel in the conduit 12 at the delivery side of the pump 14 is controlled by a fuel pressure regulator 16 and a pressure regulator 34, which will be described in more detail below.

At the lower end of the air passage 13, a delivery port 20 and a working rod
An operatively associated valve element 22 is rigidly connected to 24.

Fuel passages 8 and 9 terminate in the seat of port 20 and, when valve element 22 is in a closed relationship with port 20, the ends of fuel passages 8 and 9 also terminate, as described in detail below. It is positioned to be closed by a valve element.

The solenoid type valve actuator 25 is
And an armature 27 connected to the rod 24.
The armature 27 is loaded upwardly by a spring 28, as can be seen in the drawing, and always holds the valve element 22, so that the port 20 is closed. When the coil 26 is energized by the current, the armature moves downward in the drawing, thus displacing the valve element 22 and opening the port 20.

An air compressor 30 is connected to the air passage 13 by a conduit 31. Air at the conduit 31, and thus at the delivery side of the compressor 30, is in communication with the reference regulator.

The compressor 30 has its own air pressure regulator,
The base feed pressure can be controlled for atmospheric conditions, but this is not essential to the operation of the metering system of the present invention and will not be discussed further here. The additional, air compressor could be replaced by an alternative source of compressed gas, but this would be practical if the gas source was instead more convenient for other purposes.

Reference pressure regulator 34 serves to maintain the pressure difference between conduits 35 and 37 substantially constant. This characteristic can be explained as follows. Fuel supplied by pump 14 travels to both conduits 38 and 37. In the latter case, fuel passes through member 41 through port 40 and may or may not receive a pressure drop depending on the control of fuel pressure regulator 16. The operation of this device does not satisfy the immediate description and will be described further.

Fuel passing through conduit 37 enters chamber 48, where the fuel pressure on diaphragm 49 is created by air pressure in chamber 50a acting on the opposite side of diaphragm 49, supplementing the force applied to diaphragm 49 by spring 47. Oppose the power.
When the total force on the fuel side of the diaphragm increases above the air side force, port 51a opens, allowing fuel to flow from chamber 48 back to fuel reservoir 15 through conduit 36. Room
When the pressure in the chamber 48 tends to increase relative to the pressure in the chamber 50a, the diaphragm 49 is further displaced to increase the flow path of the port 51a, thereby preventing an increase in the fuel pressure in the chamber 48.

It will be appreciated that without the spring 47, the pressure on each side of the diaphragm would be substantially equal. Due to the spring load, a substantially fixed pressure difference can be maintained. In this case, the fuel pressure is adjusted below the air pressure, which determines the basic reference of the fuel supply pressure to the air supply pressure for the metering device 10. This pressure relationship is such that if there is no pressure drop across the regulator 16, the conduit 12
Will be reflected in 13.

The function of the controlled regulator 16 is to modify the relative fuel-air pressure of the metering device 10 by causing a pressure differential to exist between the port 40 and the conduit 37. This pressure difference is
If a fixed relationship exists between conduits 37 and 35, this will be reflected as an increased fuel pressure relative to the air supply pressure upstream of port 40. If the pressure difference across the controlled regulator 16 is high enough, the fuel pressure in the conduit 12 will
It will be appreciated that the air pressure in 13 will be above.

The controlled regulator 16 can be configured to work in various ways. It is advantageous to control the device electronically. In the illustrated example, fuel from the fuel pump 14 passes through the check valve 9 and the restriction 39, which acts only to conveniently restrict flow, but is not essential to the operation of the regulator 16. Fuel passes through port 40 via a lamella 41 that is controlled to change the flow area through port 40. Due to this change, a corresponding change in the pressure difference between port 40 and conduit 37 is established.

Although the magnitude of this change is affected to some extent by the pressure flow characteristics of the pump 14, as in the particular shape shown, the pump characteristics have little effect on the control characteristics of the regulator 16. Is convenient.

This starts from the fact that the change in the flow area of the port 40 can be achieved by the balance of the force of the member 41. This balance is primarily due to the fluid pressure at the port 40 acting on the projected area of the port, perpendicular to the member, and the electromagnetic force created by the coil 42, again perpendicular to the member 41 around the pivot 45. between.
This pivot is not essential to the operation of the device as long as electromagnetic forces can be applied directly to the valve element associated with port 40.

The electromagnetic force is conveniently created by a permanent magnet 44 that interacts with the current in the coil 42 via an electromagnetic path 43.
Thus, a force is created that is proportional to the current in the coil, which in turn creates a proportional pressure drop between the conduit 37 at port 40. Thus, the input of the current in coil 42 produces a corresponding pressure drop proportional to the current, essentially independent of the characteristics of pump 14.

It will be appreciated that there are alternative ways of controlling the pressure difference between the air passage 13 and the conduit 12 communicating with the conduit 31.

Additional information regarding the details of the construction of a device suitable for performing the functions of reference regulator 34 and control regulator 16 can be found in our International Patent Application No.PCT / AU85 / 00176 and corresponding U.S. Pat.
No. 49501, the disclosures of which are incorporated herein by reference.

Given the above relationship between the pressure of the fuel in the fuel passages 8 and 9 and the air supply pressure available in the air passage 13, the metering of the fuel is performed as follows. When the coil 26 of the solenoid 25 is energized, the armature 27 moves downward, so that the valve element 22 opens the port 20. At this stage, the air is
At the same time as fuel flows from fuel passages 8 and 9 to port 20 and is immediately entrained into the air passing through fuel delivery port 20. Therefore, as long as the solenoid coil 26 is energized, the delivery port 20
From there is a continuous flow of fuel and air.

When the coil 26 is de-energized, the valve element 22 is immediately returned to the closed position by the spring load and seats at the port 20 to deliver fuel and terminate the supply of air and fuel from the port 20.

The operation of the solenoid 25 is controlled by a suitable mechanism that energizes the solenoid in harmony with the engine cycle, and this timing can be varied according to the engine operating conditions. Discharge port 20 during solenoid energized period
Is sufficient to meet the demands of the engine at that time.

Adjusting the amount of fuel supplied can be accomplished by varying the time the solenoid is energized, or by always energizing the solenoid for a fixed period, but the number of periods the solenoid is energized during each engine cycle. Can be changed. In addition to the control gained by varying the number of periods or cycles of the solenoid, the amount of fuel delivered to the engine can be varied by controlling the fuel pressure against the air pressure, as described above. . Also, both of these controls may be operated such that the combined effect results in the required amount of fuel to be delivered to the engine.

Various well-known technologies that sense and process a range of engine conditions and generate appropriate electrical signals to operate a solenoid or similar device for regulating the amount of fuel delivered to the engine. According to the program of
Appropriate control methods can be initiated to adjust the activation of solenoid 25 and the operation of regulator 16.

Now referring to FIG. 2 of the drawings,
The metering unit 10 consisting of 60 and a solenoid unit 65 is shown in more detail. The main body 60 has a fuel inlet port 61 to which the fuel supply line 12 is connected, and an air inlet port 62 to which the air supply line 31 is connected.

The main body 60 has an axial portion 63 through which a central axial chamber 66 extends axially. The axial chamber 66 communicates with the air inlet port 62 at the upper end and has a delivery port 71 with which a delivery valve 72 cooperates, as described below. A delivery valve 72 is rigidly attached to a working rod extending from the solenoid unit 65 through the axial chamber 66.

The fuel inlet port 61 is connected to the axial portions 63 on both sides of the axial chamber 66.
In communication with two fuel passages 68 provided in the fuel cell. The fuel passage 68 has a port provided on the sealing surface 67 of the delivery port 71.
Ends with 69. As can be seen in more detail in FIG. 3, each of the fuel passages 68 has a restriction orifice 90 associated with a port 69. The holes in orifice 90 relative to passage 68 and other fuel passages leading from the fuel pressure regulator are such that the regulator and orifice determine the pressure of fuel exiting the orifice. The downstream end of each orifice 90 opens into an annular cavity 91 formed in the sealing surface 67 of the delivery port 71. Thus, the sealing surface 67 has two annular sealing surfaces 67.
It is divided into a and 67b.

In the preferred embodiment, as shown in FIG. 3, the minimum flow area provided to the gas flow from the central chamber 66 is between the sealing surfaces 67a and 67b and the valve member 72 in a special open position. It is formed in each annular limit made for it.
Annular area 66 for pressure existing downstream of port 71
The ratio of the annular area, as well as the ratio of the air pressure supply given to, determines the air pressure in the annular cavity 91. When the valve 72 is open, the pressure below the fuel pressure is applied to the cavity 91 as described above.
The air pressure is adjusted to establish
When open, fuel flow through port 71
Determined by these pressure differences.

By providing precisely specified restrictions in the fuel and air passages adjacent to port 71, differential pressure restriction and, thus, improved control over fuel delivery rate can be obtained. further,
Sealing surface created by the limited range of motion of valve member 72
Providing the restriction between 67a and 67b requires that the gas be driven by a change in valve opening caused by a desired change in the degree of interlock or stroke provided by the solenoid acting assembly connected to valve member 72. Another advantage is that the pressure developed in the cavity 91 as it flows is not strongly affected.

According to the above structure, when the working rod 76 moves upward, the delivery valve 72 is displaced with respect to the port 71, thereby opening the valve, so that both sealing surfaces 67a of the sealing surface 70 of the valve element 72 are provided.
And it is recognized that it is displaced from 67b. This opens the port 71 so that air enters through the sealing surface 67a and exits through the sealing surface 67a, with the area of the restriction created by the sealing surfaces 67a and 67b spaced at the valve 72. A pressure is established in the cavity 91 which depends on the ratio of Fuel enters the cavity and is entrained with the air and is therefore delivered to the engine as a fuel-air mixture. The pressure differential between the air in the cavity 91 and the fuel entering the cavity through the orifice 90 determines the proportion of fuel entering the air stream, and thus the proportion of fuel supply to the engine. Thus, this change in pressure difference is a factor in controlling and controlling fuel demand. Orifice
90 and the restriction provided by the sealing surfaces 67a, 67b and the valve 72 have respective fixed graduations, and
In conjunction with the regulation of the pressure difference between the fuel in the engine and the air in the axial passage 66, an effective way of metering the fuel to the engine to meet its fuel requirements is provided.

As described above, this preferred embodiment incorporates two restrictions that are spaced from valve 72 by surfaces 67a and 67b. This is because the change in the valve opening is reduced by the pressure being more strongly related to the ratio of the area of each restriction than to the size of the area of each restriction.
Has the benefit of not strongly affecting pressure. It is observed that the area of each restriction varies directly in proportion to the degree of opening of the valve 72, so that the ratio of the areas remains substantially constant, and then the pressure in the cavity 91 becomes a relatively constant pressure. .

Nevertheless, in some applications of injection systems,
It has been found advantageous to provide a flow-directed nozzle downstream of port 71 to allow more directed streamlines for outgoing fuel spray. In this variant, as shown in FIG. 4, it is advantageous to provide a fixed limiting orifice 102 upstream of the port 71, which orifice complements the fixed limiting of the directivity 105 to complete it. It is. The ratio between the fixed restriction units 102 and 105 is
For the most part, it determines the pressure in the cavity 91 for a given air supply pressure in the annular space 68 of FIG. In this case, the restriction formed by the sealing surfaces 67a and 67b on each side of the cavity 91, as described above, also affects the pressure to a much smaller extent than before.

As discussed above, when more than one fuel is provided in port 69, the fuel spray pattern, and thus changing the fuel distribution in the combustion chamber of the engine, involves adjusting the fuel flow through each port. Good. To accomplish this, as shown in FIG. 2, a restricting member 50 actuated by a fluid pressure or electric motor 51, which can be selectively protruded into the fuel passage 68 to restrict flow therethrough. It should be provided. The motor can be controlled by the processor in response to engine load conditions to provide the necessary or complete flow limit. Although only two fuel ports are shown in FIGS. 1, 2 and 3, it is preferred that at least three be provided, and more if desired. A separate passage, such as 68, can be provided for each port, or several ports can be supplied from a single fuel passage.

From the solenoid unit 65, it is housed in a cylindrical wall 90a forming a part of the main body 60, and the upper end of this cylindrical wall is sealed by a cap 91a and an O-ring 92a.
Is captured and held by the upset edge 93 of the wall 90a. Thus, the solenoid unit is within the enclosure, through which air enters through the opening 89 from the air inlet port 62 to provide air cooling of the solenoid unit.

A solenoid armature 95 is rigidly attached to the upper end of the working rod 76. A flat spring 96 is mounted centrally on the working rod 76 and the edge of the flat spring is captured in an annular groove 97. The flat spring 96 is stressed in its normal state and applies an upward force to the working rod 76 to hold the valve 72 in the closed position. An electrical coil 99 is located around the iron core 98 and is wound to produce a magnetic field when energized to pull the armature 95 downward. As the armature moves downward, the working rod 76 makes a corresponding movement to open the fuel port 69 and the delivery port 71.
When coil 99 is de-energized, flap 96 raises working rod 76 and closes ports 69 and 71. The degree of downward movement of the armature 95 is limited by the armature engaging the annular shoulder 100.

The iron core 98 of the solenoid unit has a central hole 101 communicating with the central axial chamber 66. Therefore, air port 6
Air entering 2 flows through the solenoid unit and
Enter 01 and therefore proceed to chamber 66 and pass through the delivery port when it is open. The flow of air through the solenoid unit acts to cool and help maintain its temperature within acceptable levels.

Continuation of the front page (56) References JP-A-59-96476 (JP, A) JP-A-57-76260 (JP, A) Fully open 1981-35555 (JP, U) Really open , U) Japanese Utility Model Application Showa 60-18266 (JP, U) Japanese Utility Model Application Publication No. 54-44821 (JP, U) Patent 13814 (JP, C1) Patent 15320 (JP, C1) Patent 91411 (JP, C1)

Claims (18)

(57) [Claims] A fuel delivery port (71) having a sealing surface (67) and a port (7) when the port (71) is open.
1) to communicate with the engine via
1) when closed, define a cavity (91) between two sealing surfaces (67a, 67b) of said sealing surface (67) spaced in the direction of flow through the port (71). A valve element that can be selectively opened to provide a sealing engagement with the engine, wherein fuel and gas are independently supplied to the port (71) at respective pressures, By supplying one of the fuel and gas to the cavity (91) and the other upstream of the two sealing surfaces, and periodically opening the valve element to communicate the port (71) with the engine. Allowing the fuel entrained in the gas to be delivered to the engine, the amount of fuel delivered through the port (71) for each cycle of the engine being controlled in response to the engine load, and the control being controlled by the cavity ( 91) Adjust the pressure difference between the fuel and gas This controls the flow rate of fuel to the gas in the cavity (91), thereby controlling the concentration of fuel in the gas flowing into the combustion chamber of the engine through the port (71) according to the engine load. Fuel weighing method. 2. The method according to claim 1, wherein the communication period between the port and the engine is adjusted according to the engine load. 3. A method according to claim 1, wherein fuel is supplied to the cavity (91). 4. The method according to claim 3, wherein the fuel is supplied to the cavity (91) from a plurality of spaced locations (90). 5. The method according to claim 4, wherein during operation of the engine, the number of said locations (90) to which fuel is supplied is varied to control the distribution of fuel delivered to the engine. 6. A cavity (91) in at least a plurality of locations (90).
6. The method according to claim 4, wherein the distribution of fuel delivered to the engine is controlled by changing the proportion of fuel supplied to the engine. 7. The method according to claim 1, wherein the gas pressure is maintained substantially constant and the fuel pressure is adjusted with respect to the gas pressure.
The method of any one of the preceding clauses. 8. A fuel supply means (12,14,15,16) and a gas supply means (30,31,34) each means for delivering to the same delivery port (71); A valve element operable to selectively open the port (71) to communicate the port (71) with the engine, wherein the port (71) has a sealing surface (67) when closed. ) And a valve element are provided with two sealing surfaces (67a, 67) of said sealing surface (67) of the port (71) spaced in the direction of flow through the port (71).
67b) in sealing engagement with said sealing surfaces (67a, 67).
b) A cavity (91) is defined between the fuel supply means (12, 14, 15,
16) and one of the gas supply means (30, 31, 36) communicates with the cavity (91), and the fuel supply means (12, 14, 15, 16)
And the other of the gas supply means (30, 31, 36) communicates with a port (71) upstream of said two sealing surfaces (67a, 67b);
Means for opening the port (71) by periodically operating a valve element to deliver fuel entrained in the gas to the engine via the port (71); and a port (71) for each cycle of the engine. Control means (16, 34) for controlling the amount of fuel delivered through the engine according to the engine load.
1) means for regulating the pressure difference between the fuel and the gas entering into it, thereby controlling the fuel flow into the gas and thus the fuel in the gas flowing into the combustion chamber of the engine through the port (71) A fuel metering device for controlling the concentration according to the engine load. 9. The fuel supply means (12, 14, 15, 16) includes a hollow (9).
Multiple holes (9) spaced around the perimeter of
Claim 8 in communication with the cavity (91) via (0)
The device according to item. 10. A fuel supply means (12, 14, 15, 16) and a cavity (9).
Apparatus according to claim 9, wherein means are provided for varying the number of said plurality of holes (90) communicating between 1). 11. Apparatus according to claim 9, wherein means are provided for varying the fuel flow through at least some of the plurality of holes (90). 12. A means for changing the number of holes (90) communicating with the fuel supply means (12, 14, 15, 16) and means operable in accordance with the operation state of the engine is provided.
An apparatus according to paragraph 10 or 11. 13. The system according to claim 8, wherein the means for regulating the pressure difference between the fuel supply and the gas supply in the cavity (91) is operable according to the demand for engine fuel.
An apparatus according to any one of the preceding clauses. 14. The apparatus according to claim 13, wherein the means for adjusting the differential pressure is adapted to adjust the fuel pressure in response to a demand for engine fuel. 15. A coaxial annular sealing surface (67a, 67b) having ports (71) spaced in the direction of the opening movement of the valve element.
Wherein the valve element is in sealing engagement with the sealing surface (67a, 67b) when in the closed position, the cavity (91) being coaxial with the sealing surface (67a, 67b) and Apparatus according to any one of claims 8 to 14, characterized in that it is an annular groove in the port (71) located between the sealing surfaces (67a, 67b). 16. The valve element according to claim 15, wherein the valve element together with the sealing surface forms a respective restriction on either side of the cavity when in the open position. Equipment. 17. An annular orifice (90) having a sealing surface (67a,
17. Apparatus according to claim 15 or claim 16 coaxial with and upstream of 67b). 18. An orifice (105) having a sealing surface (67a, 67).
18. The device according to claim 17, provided downstream of b).