JPS6035545B2 - Scheduled pulse fuel injection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Scheduled pulse fuel injection systems are necessary in stratified charge spark fuel engines such as diesel engines and Ford Proco engines, particularly where precise flow regulation of fuel is required to prevent air pollution. , extremely useful in conventional spark engines.

However, secondary pulse fuel injection systems are difficult to design without flow regulation errors due to pressure pulsation of the fuel. This pressure pulsation behavior introduces dynamic errors, especially in high pressure and very high speed systems where the bulk modulus of compressibility of the fuel is important. A device that accurately regulates the flow rate on a cylinder-by-cylinder and cycle-by-cycle basis is likely to lose control of the fuel piston mass over time and become extremely expensive. Additionally, pulse fuel injectors are susceptible to atomization failure at very low engine speeds. This problem contributes to the cold starting problem of diesel engines and has persisted to some extent despite extensive engineering efforts. It is an object of the present invention to be easily coupled to an air-fuel control system, to provide highly accurate flow regulation with relatively low precision and inexpensive components, and to provide flow characteristics of the operating components that are consistent with that of the engine. It is an object of the present invention to provide a scheduled pulse fuel injection device that can maintain good flow regulation at all speeds even as it varies with wear and deposits over its lifetime.

Another object of the invention is to provide an injector that is adaptable for very high pressure in-engine injection and low pressure injection.

Another object of the present invention is to provide a scheduled pulse fuel injection system that is completely insensitive to pressure pulsation behavior in the various injection lines and that provides excellent flow regulation at any practical engine speed, such as 15,000 RPM and above. The purpose is to provide equipment.

Yet another object of the present invention is to provide a scheduled pulse fuel injection system that has little error in flow regulation due to variations in injection lines and injection nozzles that have varying flow pressure characteristics. Yet another object of the present invention is to provide a scheduled pulse fuel injection system that provides instantaneous high flow and good atomization even during engine startup, and is capable of rapid shutoff of flow to prevent nozzle dripping. It is to be.

A further object of the invention is to provide an injection pump in which the fuel flow rate is a linear function of the control valve position, in order to simplify the design of the fuel-air ratio control device.

The present invention is distinguished from prior art injection systems in that the prior art injectors use very high pressure pulsating flow regulating pumps or devices from a common pressure source with rapidly pulsating valves. .

The present invention utilizes a substantially continuous flow pump to supply pulses of fuel to individual injection nozzles through a cascade of accumulator chambers. This cascade of accumulator chambers is configured such that the mass of fuel delivered per pulse is insensitive to variations in fuel flow resistance between different injection nozzles. These and other objects of the present invention simplify the function of each actuating component, eliminate sources of interaction between the components that create errors in fuel pulse flow regulation, and reduce the distance of fluid pressure wave travel between the flow regulating components of the device. Each working part has a geometrically simple shape and This is achieved by providing a device with mathematically well-defined and simple static and dynamic functions.

Specifically, the pump has a pressurizing function but no flow regulating function.

The total flow regulation is effected simply and continuously by means of a variable flow regulation orifice producing a constant pressure drop, which is controlled by the interaction of three accumulator chambers connected in a pressure cascade sequence to the injection nozzle by a rotary distributor. The voltage is divided into equal volumes and supplied as pulses. Each accumulator chamber releases its capacity as a kind of fluid condenser when opened to the downstream accumulator chamber, so even at very low engine speeds the flow is sufficient to ensure good atomization. It is in the form of a high-speed pulse. Due to the close proximity of the accumulator chambers to each other, the filling and dispensing of fuel into the accumulator chambers is always complete upon closure of the rotary distributor, and the harmful pressure pulsations occurring in the injection lines and nozzles are prevented by flow regulation. It does not have any influence. Each of the working parts of the device of the invention includes:
It is of simple construction and most of the parts have wide tolerances, so the overall cost of the device is much lower than that of older injection pumps, which were hitherto very expensive. If shaping of the injection pulse is required, excellent pulse shaping can be obtained by providing an adjustable throttle valve between the n accumulator chambers ch3i and the nozzle.

Continuous fuel flow regulators can also be easily adapted to a certain pressure maximum in order to ensure that the fuel capacity per injection pulse does not exceed a certain set point. The fuel whose flow rate is regulated flows into the accumulator chamber chi.

This accumulator chamber chi only stores a volume above a certain pressure Pa, and is intermittently connected to the accumulator chamber ch2 through a rotary distributor once during each injection pulse. The accumulator chamber Ch2 accumulates only the capacity above the pressure P. Therefore, all the fuel whose flow rate is regulated while accumulator chamber ch2 is connected to accumulator chamber chi, as well as the entire fuel stored in accumulator chamber chi after the previous connection period, is During this period, it flows into the accumulator chamber ch2. When the accumulator chamber Ch2 is disconnected from the accumulator chamber Ch2, it makes an intermittent sequential connection with one of the n injection nozzle lines through the rotary distributor. Each of the injection nozzle lines has an accumulator chamber ch3i;
Accumulator chamber Ch3i accepts the capacity accumulated in accumulator chamber ch2 and transfers it to Pa
Store at a pressure Pa3i lower than 2. The volume transferred into the accumulator chamber ch3i is discharged through the i-th injection nozzle. Accumulator Chamber Ch
i, ch2, and ch3i are configured such that the capacities of these chambers do not change at pressures lower than pressures Pa, , Pa2, and Pa3i, respectively. Therefore, fluctuations in the discharge pressure between accumulator chambers ch2 and Ch3i do not result in errors in flow regulation as would occur in repeated connections between accumulator chambers chi, ch2 and a continuous fuel flow regulation device. The pressure cascade system allows the total operating speed to be maintained as long as each injection nozzle i has a suitable flow rate at a pressure below P, the inequality Pa > P > Pa3i holds, and the rotary distributor is sealed. Over a wide range of ranges and design parameters, the device has the advantage of minimizing fuel pulse mass cycle-to-cycle and cylinder-to-cylinder variation. Therefore, there is no need to balance the length of the injection nozzle and the injection line, and the device can operate at very high speeds. The device can be modified to produce the desired square wave pulse shape at maximum fuel flow per crank angle.

This device can also be used in conjunction with a pressure suppressor in order to prevent the injection amount per pulse from exceeding a set maximum value for preventing fuel enrichment. Next, embodiments of the present invention will be described with reference to the accompanying drawings.

Referring to FIG. 1, a rigid metal tube 1 with a hole in the wall is covered with a flexible elastomer tube 2 (eg, a commercially available high pressure nylon fluid tube).

The phestomer tube 2 is subjected to considerable elongation and tension, and grips the rigid metal tube 1 with considerable force at all times. The ends of the elastomeric tube 2 are sealed by clamps 3, 4 around the rigid metal tube 1, making it leaktight under internal pressure. The accumulator chamber formed by these components 1 , 2 , 3 , 4 is capable of holding its own as long as its internal pressure is less than the gripping force on the rigid metal tube 1 provided by the tension of the engineered elastomeric tube 2 . Although the fluid capacity remains unchanged, if the internal pressure exceeds this force, the elastomer tube 2
expands further and the capacity of the accumulator chamber increases with increasing internal pressure. When the internal pressure is relieved again, the elastic tension of the elastomer tube 2 forces the accumulated volume out of the accumulator chamber. The accumulator chamber is a very simple example of a resilient accumulator chamber with a mechanical stop, with the elastomer tube 2 serving as the expandable chamber and the rigid metal tube 1 serving as the stop. Accumulator chambers formed in this way are extremely fast acting, can be designed using well-known material strength formulas, are extremely durable, and are extremely cheap to manufacture. The interaction of 20n accumulator chambers of the type shown in FIG. 1 forms the pressure cascade structure of the present invention. Each accumulator chamber has an accumulated pressure below which its capacity remains unchanged, which depends on the tension at which the elastomer tube 2 rests against its inner tube stop. Figure 2 shows
For the functions V(P), , V(P)2 and V(P)3i (where i=1, 2, 3,...n), the pressure and storage capacity exhibited by an accumulator chamber of the form of FIG. Indicates the relationship between

Below certain characteristic internal pressures Pa, , Pa2 and P, the accumulator chambers chi, ch2 and ch3i each have a constant capacity with respect to the pressure. The accumulator chambers chi, ch2 and ch3i store capacities that gradually increase with pressure for pressures above Pa, , Pa2 and Pa3, respectively. For pressure pulsating operation, the graph of pressure-storage capacity relationship of the accumulator chamber shown in Fig. 2 should deviate to some extent, but while the pressure and capacity are increasing and the pressure (and therefore capacity)
is decreasing (evacuation of accumulator chamber)
, the accumulator chamber follows the relationship shown and shows a very good approximation even at very high speeds. Accumulator chamber Chi is at pressure Pt. Assuming a quick fluid connection with the accumulator chamber ch2, which has a capacity stored at
As long as the storage capacity of i is smaller than Vm, the entire storage capacity of accumulator chamber chi is transferred very quickly to accumulator chamber ch2 and is stored there at a lower pressure P. Similarly, accumulator chamber ch2 (accumulator chamber c
) is cut off from accumulator chamber c
When fluidly connected to h3i, the accumulator chamber ch
Unless the storage capacity of 3i is sufficient to increase its pressure to Pa2, a complete fluid transfer of the storage volume from accumulator chamber ch2 to accumulator chamber ch3i takes place. The function representing the relationship between the capacity and pressure of the accumulator chamber shown in FIG.
The maximum possible pressure in accumulator chamber Ch3i is P3Max (P3iMax<P2iMax
<P, iMax) and therefore the pressure drop between accumulator chambers chi and ch2 and between ch2 and n
It should be noted that ch3i has the property that it always exists between any one of the accumulator chambers ch3i. This pressure drop ensures complete transfer of the storage volume between the hair accumulator chambers towards the injection nozzle in the pressure sequence. This sequential transfer process of storage capacity from a higher pressure accumulator chamber to a lower pressure accumulator chamber is complete, very far, and in order to ensure that the transfer occurs over a certain pressure drop, Pu>Pt2 >As long as Pt3i,
It does not depend on the exact values of Pa,, Pa2, and Pax. This transfer process between accumulator chambers connected in series by rotary distributors is the essence of the invention.

Accumulator chambers chi and ch2 are intermittently connected, and accumulator chamber ch2 is intermittently connected to n accumulator chambers ch3i that feed n nozzles
Connect sequentially. The pressure cascade transfer process filters out the extra regulation cycles of the interaction of the accumulator chambers CHI and CH2 from the harmful effects of fluctuations between the various n injection lines, and the pulses of fuel flow are a kind of capacitive Since it is generated by the discharge, it ensures that the instantaneous flow rate is sufficient for atomization even under start-up conditions. Since each of the cascaded accumulator chambers can be physically close to each other, high speed limitations due to the finite speed of sound in the fuel do not significantly limit the operation or accuracy of the device of the present invention. If the various injection lines are unbalanced, the regulation pulse may have a variable delay in reaching the injection nozzle, but this phase shift does not affect the regulation result itself. FIG. 3 shows in block diagram form the fuel flow sequence of the scheduled pulse fuel injector.

The rotary distributors LI and L2 are normally rotated synchronously on a common shaft, so that the accumulator chamber ch
2 is alternately opened to the accumulator chamber chi and one of the accumulator chambers ch3i. FIG. 4 schematically illustrates the flow pattern of the scheduled pulse fuel injection system of the present invention.

The flow rate of pressurized fuel from the pressure source P is continuously regulated via a flow rate control device consisting of a variable flow rate regulating valve V and diaphragm control bypass systems 24, 5, and 6. Bypass system 24
, 5, 6 maintain the average pressure drop across the variable flow regulating valve V at a constant value to ensure accurate fuel flow regulation at each set position of this valve V. This flow control device includes bypass systems 10 and 11 that short-circuit the flow downstream of the flow rate regulating valve V that exceeds the set maximum pressure. This bypass system ensures that the flow regulation capacity per injection pulse does not exceed the set value. The regulated fuel flows to accumulator chamber chi and then to ch2, and when accumulator chamber chi becomes the first switching device and is isolated from accumulator chamber ch2 by the rotary distributor LI of the bell, the accumulator chamber Chi
When accumulator chamber chi is connected to accumulator chamber Ch2 via a rotary distributor LI, it flows directly into accumulator chamber ch2. The accumulator chamber Ch2 becomes a second switching device that is always open, and the pressure is passed through the middle level distributor L2 to the distributor LI and the pressure reducing bell distributor L3.
The distributor L2 is shaped so that the flow path between the accumulator chambers Chi, Ch2, and ch3i does not change from injection cycle to injection cycle. Accumulator chamber ch2 is accumulator chamber C
The accumulator chamber ch2 during part of each injection cycle when disconnected from the hl and flow regulator.
is one of the n accumulator chambers ch3i in the rotational sequence via the distributor L3 per injection cycle.
and discharges its entire storage capacity into this accumulator chamber ch3i. This process is always completed during the connection of accumulator chambers ch2 and ch3i. The accumulated fuel in accumulator chamber ch3i is maintained at sufficient pressure to cause nozzle i to inject at high velocity. The injection speed is reduced from this maximum speed,
The fuel pulses are given the desired shape by the setting of needle i in line i, which is controlled in conjunction with other needles to control the maximum injection speed as an increasing function of rotational speed RPM or other parameters. . Accumulator chamber c
After h2 discharges fuel into the accumulator chamber ch3i, the connection between ch2 and ch3i is broken by distributor L3, and the fluid connection between ch2 and chi is reestablished through distributor LI.

The cycle is then repeated, this time with injection in the next injection line. Accumulator channel chimney C
After discharging to h3i, the capacity of the accumulator chamber ch2 does not change with the fluctuation of the pressure in the injection line accumulator chamber ch3i as long as Pqm is smaller than P, so the continuous fuel flow control device and the accumulator chamber ch2 , ch2, the flow regulation results are substantially unaffected by dynamic and other variations between the various injection lines.

The only exception is that when the connection between ch2 and ch3i is broken, the fuel density in the accumulator chamber Ch2 changes slightly with pressure because the fuel bulk modulus is not infinite. . This effect is imperceptible in low-pressure equipment, and is small even in ultra-high-pressure equipment. Therefore, it can be said that the flow regulation of the present device is almost unaffected by variations between the injection line and the nozzle. Therefore, accuracy of flow regulation does not require that the flow characteristics of the injection line and nozzle be closely matched. FIG. 5 shows the flow pattern of a preferred embodiment of a rotary distributor as a switching device.

The cylindrical rotating member 12 rotates within the receiving chamber 13 . Rotating member 12 and receiving member 13 form a fluid seal. As a result, only the flow occurs between the accumulator chamber Chi, the accumulator chamber ch2, and the accumulator chamber ch3i (i=1, 2, 3, . . . , n). The fluid passageways in the rotating member 12, shown as a series of solid lines in FIG. 5, are then aligned with the passageways in the receiving villages 13 feeding these accumulator chambers. As shown, the rotary distributor has three levels,
That is, the rotary distributor upper bell LI opens and closes the connection between the accumulator chamber chi and the flow path in the rotating member 12 eight times every rotation, and the accumulator chamber Ch2 is always in fluid connection with the chamber at the rotary distributor middle level L2. In the rotary distributor, as shown in FIG. level L2 and a rotation with a flow path connecting one of the accumulator chambers ch3i with a passage in the rotary member 12 whenever the flow between the passages of the rotary member 12 is cut off from the accumulator chamber chi. The distributor has a lower bell L3. These three rotary distributor levels L1, L2, L3 are interconnected by a hole in the center of the rotary member 12. Rotary distributors of the type shown in FIG. 5 have been successfully used in a number of injection systems that use rotary distributors. Although various other types of rotary distributors can be used to perform the flow switching function between the accumulator chambers, many of these alternative rotary distributors are within the skill of those skilled in the rotary distributor art. It is self-evident.

As can be seen from FIGS. 4 and 6, pressurized fuel from the pressure source P flows into the accumulator chamber chi via the flow rate regulating valve V.

When accumulator chamber chi is isolated from ch2 by rotary distributor upper bell LI, fuel is accumulated in accumulator chamber chi. When the accumulator chamber chi is connected to the accumulator chamber ch2 via the rotary distributor top bell LI, the fuel flow path is generally directed to the center of the rotary member 12, as shown by the dashed line in FIG. However, for ease of understanding, it is conveniently shown by a broken line in Figure 4.
It is transferred from chi through the center CI of the rotary distributor LI to the accumulator chamber ch2. Since the accumulator chamber Ch2 is always open to the flow paths of the upper bell LI and lower bell L3 of the rotating distributor through the middle level L2 of the rotating distributor which is always open, the accumulator chamber C
The fuel from h2 passes through the annular slot S in the rotary distributor intermediate level L2 and the center C2 of said intermediate level, from which the flow path does not in principle pass through the center of the rotary member 12, as shown by the dashed line. It is transferred to the center C3 of the rotary distributor lower level L3, which is conveniently shown in broken lines in FIG.
h3i respectively. In diesel engines and some stratified charge spark fuel engines,
In addition to regulating the fuel flow rate, the shape of the fuel pulse is also important.

In general, a rational pulse injects a certain amount of fuel flow per crank angle at all speeds with a generally shaped square wave pulsed flow, quickly reaches its maximum flow rate, maintains this flow rate throughout injection, and then It has the property of abruptly cutting off fuel flow. Cascade injection pump systems currently in use cannot possess these characteristics unless modified with pulse shaping means. This pulse shaping is the sixth
This is accomplished by the device shown in the figure.

In FIG. 6, each of the n injection lines has a variable area needle valve in the line between the accumulator chamber ch3i and the nozzle i, and the n needle valves are such that each needle valve is different from the other needle valves. are connected to have an orifice entrance equal to the orifice entrance. These needle valves are connected through cog assemblies 15, or some other linkage, and are controlled in opening □, an increasing function of rotational speed RPM (control mechanism not shown). Referring to Figure 7,
Flow rate m of nozzle i, which is a pintle nozzle that closes outward
is an increasing function of the pressure drop across the nozzle, and the equation fn
=k, (pn-pd) is expressed as (pn-pd-po).

Here, m = instantaneous flow rate of the nozzle Pn = instantaneous pressure on the upstream side of the nozzle pd = instantaneous pressure on the downstream side of the nozzle po = pressure drop with respect to nozzle opening (it is said that the pressure drop when the nozzle opens is equal to the pressure drop when the nozzle is closed) (based on approximations) k, = flow constants for the nozzle geometry If the flow constants pd and po are constant, determining the nozzle flow rate means determining the nozzle pressure pn.

The accumulator pressure in the accumulator chamber ch3i is always at least as high as is sufficient for the design maximum nozzle flow rate of the device.

In order to reduce this maximum nozzle flow rate, the needle valve adjusts the fluid pressure in the accumulator chamber Ch3i to the desired flow rate (RP
(proportional to M) to a pressure pn corresponding to The pressure drop across the needle orifice is proportional to the square of the flow rate through the orifice (the square of the volumetric flow rate divided by the square of the orifice area), where Δp=open f.

In the above equation, △p = Pressure drop across the needle valve m = Instantaneous volumetric flow rate a = Cross-sectional area of the needle valve orifice opening k2 = Shape of the needle valve Flow constant The pressure drop across the needle valve for each specific volumetric flow rate is the setting of the needle valve. It is largely related to the value a, and this set value determines the equilibrium nozzle pressure pn and the equilibrium nozzle flow rate m.

Specifically, the flow interactions between the nozzle, accumulator chamber, and needle valve react such that the flow oscillates about an equilibrium state, which is defined by the general equation (where pat is is the instantaneous pressure of the accumulator chamber ch3i):Pn=PyamaichiΔp, or pn:pa−hair−fIn the case of a device containing a focusing nozzle that closes outward, f
Substituting the lid, the equilibrium state becomes:

pn = enemy - 4 and a half (pn 3 - 3 days 2 shame - sand n 2 ratio 13 pn
pd214pnpdp.

Ten pnp. 2-pd3 single d too.

-pdp. 2) This equilibrium state is extremely stable.

The range of cross-sectional areas a of the needle orifice passageway entrances required of the injector is proportional to the required flow range multiplied by the square root of the desired range of needle pressure drop. For example, the RPM range (
fn), and for a particular variation of P and pd, the range of pressure drop across the needle valve to achieve that variation is within the range of one diagonal of Δp. requires a 40 times change in orifice area from the maximum flow setting to the minimum flow setting. This 40:1 change in the cross-sectional area a of the orifice entrance results in a change in the negative feedback coefficient of nozzle equilibrium of 4.600:. In many practical cases, the required range of a will be 40:1 or less. Design parameters k. , k2, po and the pressure-volume function of the accumulator chamber, the interaction of the accumulator chamber, needle valve, and injection nozzle is such that the desired square wave pulse characteristics are excellent. Show approximation.

The pulse shaping device is stable even at the highest operating speeds required. FIG. 7 shows the injection between the accumulator chamber, the needle valve in the line, and the outwardly opening pintle nozzle, assuming that the nozzle downstream pressure pd and the accumulator chamber pressure p are constant. The balance of the flow rate m is shown to explain the function of the needle valve pulse shaping device. Pulse shaping by the needle valve device does not affect the flow regulation regime of the accumulator chamber pressure cascade process, since the duration of the injection pulse is much shorter than the time between successive injections of the same line, and therefore each accumulator When chamber ch3i first connects with accumulator chamber ch2 through the fluid distributor, each accumulator chamber ch3i is completely evacuated.

Variations in the pressure-flow characteristics of the n accumulator chambers ch3i, n nozzles and n needle valves, and variations in the line length can result in variations in the pulse characteristics of the injection line.

However, if the design parameters are properly matched, the pulses will also be matched and each nozzle will have the desired square wave pulse. Needle valve pulse shaping technology
Because it does not require a plunger or cam profile with inertial mass to constrain the shape of the pulses, it more closely approximates ideal square wave injection characteristics than conventional injection pumps.

FIG. 8 shows a continuous flow fuel flow regulating device adapted to a scheduled pulse fuel injection system.

Fuel is continuously regulated through the flow restriction valve V and the average pressure drop across the flow restriction valve V is maintained constant by the diaphragm controlled bypass valve assembly 24, 5, 6 as long as the downstream pressure is below a set maximum value. . Fuel pressurized by pump P enters line 21 where the flow is split into fuel flow to the engine through flow restriction valve V and fuel flow to the bypass through needle valve assembly IJ24. The needle valve assembly 24 is opened and closed by the diaphragm 5. That is, the diaphragm 5 opens when the pressure in the chamber la exceeds the pressure in the chamber lb plus the pressure of the spring 6, and the pressure in the chamber la exceeds the pressure in the chamber lb plus the pressure of the spring 6. , so that the average pressure drop across the flow regulating valve V is maintained at a pressure drop corresponding to the force of the spring 6. The spring 6 is designed with a spring constant to actuation force ratio such that the force acting on its diaphragm 5 is approximately the same when the bypass valve assembly 24 is fully open as when it is fully closed. The chamber lb is connected to a line 7 via a porous plug 8 at a downstream pressure of the flow rate regulating valve V.

The flow through the porous plug 8 is completely constricted so that rapid pressure fluctuations are not transmitted (ie pressure transmission requires fluid flow and the bulk modulus of the fuel is not infinite).
Flow over the pressure cycle of the device through porous plug 8 serves to maintain chamber lb at the average cycle pressure of line 7. The pressure in line 7 fluctuates rapidly with the opening and closing of accumulator chamber Chi relative to accumulator chamber ch2, and the vibrations of the flow regulation device may result in unacceptable cycle-to-cycle flow regulation errors at the very high operating speeds required. The function of the porous plug 8 to suppress servo vibrations of the bypass device is important. Since the bypass device cannot be made to maintain a constant instantaneous pressure drop across valve V, it is instead designed to maintain the average pressure drop very precisely from cycle to cycle.
As shown in FIG. 2, the interaction between accumulator chambers chi and ch2 is such that a certain average cycle pressure in line 7 corresponds to a certain fuel flow rate per injection pulse. This relationship between the average pressure in line 7 and the fuel volume per pulse can be understood by considering the pressure-storage volume relationship of FIG. Therefore, setting the maximum allowable average pressure in line 7 depends on the rotational speed RPM
Establish a maximum fuel volume per injection pulse that is substantially independent of . Figure 8 Pressure Override Bypass 1
0,11 accomplishes this. Stop 10 is chamber l
Opens when the average pressure in b exceeds the force of spring 11, the reduction in pressure in chamber lb causes diaphragm 5 to open bypass valve 24 to further reduce the device pressure. Therefore, the device cannot maintain an average pressure in line 7 that exceeds the set opening pressure of bypasses 10,11.
Therefore, the fuel volume per injection pulse cannot exceed a set value corresponding to this maximum average pressure in line 7. The structure of FIG. 8 can be modified in various ways to accommodate requirements, such as adapting the device to very high injection pressures.

The diaphragm 5 can be replaced by a piston assembly to control opening and closing of the bypass device. This adaptation of the pressure compensating, fluid flow regulating device is well known in the pure fluid technology field and is particularly well adapted to very high pressure drops across the flow regulating valve V. A large pressure drop is advantageous for certain devices since it is important that the pressure drop across the flow regulating valve V must not change direction. The pressure equalizing action of the porous plug 8
This can also be achieved by a very small orifice between chamber lb and line 7, thereby controlling the maximum fluid transfer rate between chamber lb and line 7 and thus limiting the rate of pressure equalization between the two chambers. These and other modifications of continuous fuel flow regulation devices will readily occur to those skilled in the pure fluid arts, where a large body of precision continuous flow regulation literature exists. The accuracy of the device shown in FIG. 8 or the pressure compensation and flow rate regulation device decreases when the pressure within the chamber la fluctuates and becomes out of phase with the injection flow rate regulation result.

It is best if the pressure on the upstream side of the flow rate regulating valve V is maintained constant over a period of several cycles, but this can be achieved by arranging a surge tank between the pump P and the flow rate regulating valve V, or This can be accomplished by a number of well-known techniques, such as placing a suitably selected length of elastic tubing between the pump P and the flow restriction bypass device. The technology of elastic tubes is
It has the advantage that less volume needs to be accumulated before achieving the desired pressure change. Other continuous flow regulators may be used in place of the flow regulator shown in FIG. 8 to provide continuous flow regulation prior to the pressure drop cascade distribution device.

For example, the flow rate can be adjusted by some type of variable displacement pump. A number of continuous fluid flow regulators
The cheapest and most durable one that can accomplish the purpose of the device shown is the best. Table 1 summarizes in tabular form the design requirements and functions of the components of the scheduled pulse fuel injection system of the present invention.

The design tolerances of most of the components of the device are extremely wide, with the rotary distributor being the only component that must be made to very close construction tolerances for sealing purposes. The requirements for the components of this device are:
It is very similar to operate at an injection pressure of k9/,
And the difference in manufacturing costs between high-pressure and low-pressure devices is primarily due to the increased cost of the pump with increasing pressure. As noted in Table 1, each working component has a geometrically simple shape and a mathematically well-defined purpose, the function of each component is simple, and secondary flow regulation errors are avoided. The sources of interaction between the parts that occur are eliminated,
Since the equilibrium between the parts is sequential rather than simultaneous, and the fluid pressure wave travel distance between the flow regulating parts is very much 4 cm, the desired interaction between the flow regulating parts is always within the available time. Complete.

Table 1 Functional design requirements for equipment components Table 1 continued)

[Brief explanation of drawings]

FIG. 1 shows the preferred form of an accumulator chamber for use in the scheduled pulse fuel injection system of the present invention. FIG. 2 shows the pressure-storage capacity relationship of the accumulator chambers shown in FIG. 1 and the required mathematical relationship between the accumulator chambers in the present injector. Third
The figure shows the fuel flow sequence of the present injector in a block diagram. FIG. 4 is a schematic diagram of the entire injection device. FIG. 5 is a partially cutaway view of the rotary distributor for the present injection device. 6th
The figure shows the structure of the needle valve pulse shaping device for the present injection device.
FIG. 6A is a cross-sectional view of a pulse shaping needle valve. FIG. 7 shows the flow balance characteristics of the needle valve pulse shaper interacting with the nozzle and accumulator chamber ch3i. 8th
The figure shows a continuous flow fuel flow regulating device adapted to a maximum pressure setting which, when installed in a pressure cascade device, ensures that the fuel volume per injection pulse does not exceed the set maximum value. . Explanation of symbols, chi, c
h2, ch3i...Accumulator chamber, 1.
... Rigid metal tube, 2 ... Elastomer tube, 3, 4 ... Clamp, 5 ... Diaphragm, 6 ...
... Spring, 8 ... Porous plug, 10, 11
...Bypass device. Figure 1 Figure 2 Figure 3 F/6.4. '/G. 5. FIG. 6. FIG. 6A. r/G-〆FIG. 8.

Claims (1)

[Claims] 1 In a scheduled pulse fuel injector that injects fuel pulses through n nozzles in a repetitive sequence, (
a) n+2 accumulator chambers ch1, ch
2, ch31, ch32, ch33, ..., ch3n; (b) a device for continuously regulating the flow rate of the pressurized fuel flow to the accumulator chamber ch1; Yumura Chamba ch31, ch
32, ch33,..., ch3n, thereby connecting nozzle 1 to accumulator chamber ch31, nozzle 2 to accumulator chamber ch32, and so on. n nozzles 1, 2, 3, . In order to open and close the flow, a first switching device connects the accumulator chamber ch1 and the accumulator chamber ch2, and from the accumulator chamber ch2 to the accumulator chambers ch31, ch32, ch33,
..., accumulator chamber ch2 and accumulator chamber ch to open and close the fluid flow to ch3n
31, ch32, ch33, ..., ch3n, and is a second switching device that connects the accumulator chamber c.
From h1 to accumulator chamber ch2, from accumulator chamber ch2 to accumulator chamber ch3
1, then from accumulator chamber ch1 to accumulator chamber ch2, then from accumulator chamber ch1 to accumulator chamber ch2.
2 to accumulator chamber ch32, etc., until all accumulator chambers ch33,...,...,3n accept fluid once, then the cycle goes from accumulator chamber ch1-ch2, etc.
ch2-ch31; ch1-ch2, ch2-ch32
;ch1-ch2, ch2-ch33; etc., ch1-c
a first switching device and a second switching device configured to repeat up to h2, ch2, ch3n; (e) each accumulator chamber having a fixed volume of fluid and a variable volume of fluid referred to as storage fluid; However, a small amount of fluid, such as fluid, accumulates below the set opening pressure, and the accumulator chamber rapidly accumulates fluid above the opening pressure, and the opening pressure of each accumulator chamber is equal to the opening pressure of the preceding one. It must be sequentially smaller than the opening pressure of the accumulator chamber, and the opening pressure of the accumulator chamber ch1 is greater than the opening pressure of the accumulator chamber ch2.
The opening pressure of accumulator chamber ch2 becomes greater than the opening pressure of the last accumulator chamber ch3n, such as accumulator chamber ch31, accumulator chamber ch32, or accumulator chamber ch33, etc. A scheduled pulse fuel injection device comprising: