JPH0350378A - Cylinder fuel injector - Google Patents

Abstract

PURPOSE:To improve stability of flow rate characteristics of dynamic flow rate during transition of injection for correctly grasping the dynamic flow rate by providing a fuel measuring unit for regulating fuel injection amount per injection before an injection port at the tip of an injector. CONSTITUTION:An injector for directly injecting fuel into a cylinder of two-cycle engine is provided with a two-piece structured valve member 16 in a housing 12 for guiding freely movably a first valve member 18 provided with a valve head 22 at the tip along the axis by a guide member 8 and a sheet member 10. In this case, a cone-shaped fuel injection port 26 expanding outward is formed at the tip of the sheet member 10. In addition, a fuel measuring unit 94 for giving a constant flow path cross-sectional area corresponding to difference between the cross-sectional area of a fuel path 60 and the cross-sectional area of the valve member in the flowing direction over specified length and regulating fuel injection amount per injection is formed before the injection port 26 by providing a neck 95 at the foot of the valve head 22.

Description

[Detailed description of the invention] Industrial application field> This invention is a method for injecting fuel into the cylinder of an engine! 1)I
The present invention relates to an in-cylinder fuel injection device suitable for, for example, a 21-frame engine that performs forced scavenging to push in pressurized air.

<Prior Art> In contrast to the intake pipe injection device that injects fuel into the intake pipe of an engine, the in-cylinder fuel IIm injection arrangement injects fuel directly into the engine cylinder. It is used in two-stroke engines as shown.

This includes two intake valves 10/'I and two JJI air valves 106 in the cylinder head 102 of the cylinder 100, and an ignition system 112 including an ignition oil 108 and an ignition plug 110. 1 intake manifold 11/I is provided with a mechanical supercharger t116 as a supercharger, and the rotation of two cocoon-shaped rotors 120 driven by crank shirts 1 to 118 is controlled by L. The cylinder head 102 is equipped with an in-cylinder fuel lli equipment FJ 122 that blows out the fuel r1 directly into the cylinder 100. is set up.

Then, as shown in the upper part of FIG. 10, dry firing occurs due to the ignition device 112 at the top dead center of the piston 124, and as shown in the lower right, the bottom half of the screws 1 to 124 due to expansion occurs. 1]-down, the 1-no-1 air valve 106 is heard. Furthermore, the intake valve 104 is also closed, as shown in the lower row. 116 J: Pressurized air is fed into the cylinder, and the combustion force (1j1 gas) in the cylinder is forcibly scavenged through the exhaust 1 to manifold 126. Fuel is injected into the in-cylinder fuel injection device i1122 into the resylinter, and the air-fuel mixture is compressed by LE, resulting in the above-mentioned trouble. 1 Injectors proposed as such in-cylinder fuel injection DA devices generally include an outward-opening valve member that opens and closes the fuel injection port of the housing from the outside, and the valve member is attached to the housing by a spring means. When the valve member is pulled inward and held in the closed position with υ, the injection port is opened by pushing out the valve member against the biasing force of the spring means using an electromagnetic drive means such as a solenoid. Normally, fuel is injected in the open state. , an intake pipe injection type engine, "The lid generally has an internal valve, and the valve member is pressed against the valve seat in the housing by a spring means to maintain the open state, and the valve member is pressed by an electromagnetic drive means. “To draw you in”:
In contrast to the in-cylinder injector, which moves in the opposite direction, the external valve system is adopted because the valve member, whose end face is exposed inside the cylinder, is exposed to explosion pressure. This is to prevent the valve from opening.

In addition, in such an injector with an external valve structure, a fuel metering section is usually provided in the fuel passage in front of the fuel injection port in order to regulate the amount of fuel injected per injection. .

This h1 part corresponds to the nozzle hole of an inner valve type injector, and has a certain flow passage cross-sectional area corresponding to the difference between the cross-sectional area of the fuel passage and the cross-sectional area of the pallet 1 part 4A. It is a part that can extend over the length.

<Problems to be Solved by the Invention> Incidentally, in the past, such a portion of the fuel h11 was stored at the tip of the injector (fuel D) as shown in FIG. 11(a), for example.
i (1 direct passage from the mouth of the river). This combustion station is
Assuming that the top of the combustion passage is Sl and the valve cross-sectional area is S2, 8
The cross-sectional area of the flow path is 1-82, and the length is +11 in the flow direction.

However, 1; e sa 01 of this Fil ff1 part is for closing the valve, and when the valve l is open, the word length is Q2 as shown in FIG. 11(b). 1, where the relationship is β2<01, and the length of the 61 part changes by 1~[1-min] when the valve is closed. As a result, the fuel flow rate changes with the displacement of the valve member, and the fuel flow rate during the transition period loses its linearity, resulting in a static flow path (flow rate when the valve is fully open) and a dynamic flow path (flow rate when the valve is actuated). The linearity between is lost.

This will be explained in detail in history. In general, the flow IQ of a fluid in a circular pipe is determined by Hagun-Poij's law: Q= (Pi
-P2) πa'/(8ρμ) However, Pl: Pressure before the circular tube []2: Circle @ rear force a: Radius of the circular tube fJ=Circular tube length μ: The viscosity coefficient holds true. As will be understood, the flow faQ is 1
The change is proportional to /41. In other words, if the displacement of the valve member in the opening direction in FIG. 11(a) is 8β, then 1/Δβ
It will change in proportion to. Therefore, even if the static flow rate when the valve is fully open can be accurately determined, when the valve is operated (
A problem arises in that the dynamic flow rate during the transition period cannot be accurately grasped.

In other words, as shown in Figure 12, the length of the Mobetsu word hanging part is 9.
is not constant, the dynamic flow rate does not match: i'I'5 f+, and the deviation is large.

An object of the present invention is to stabilize the dynamic flow rate flowing into the fuel 11 draining section.

<Means for Solving the Problems> The solid internal combustion rock injection QJ according to the present invention includes, for example, an intake valve installed in the cylinder head from the above-mentioned J, Usu 21 Neukle engine, '). It is equipped with a 1-1 air valve and an ignition system, and a supercharger that sends air into the cylinder through the intake valve, and when both valves are open, the air is pumped in from the supercharger. It is suitably used in a 2-recycle engine that uses forced scavenging, and injects fuel into the cylinder, and is configured as follows.

That is, a housing in which a fuel passage is formed;
A valve member that is moved between closed positions to open and close the fuel injection port of the housing from the outside of the housing, and a spring means that constantly urges the valve member to the closed position. The valve member is pressed against the biasing force of the means.
The electromagnetic drive means that moves 100,000,000, and the fuel passage is provided in front of the mouth of the fuel passage 11, and the cross-sectional area of the fuel passage is the difference between the cross-sectional area of the valve part + J. A fairly constant cross-sectional area of the flow path is defined as rAf;+"t',i
It has a predetermined length in the J direction, and includes a fuel R4-fyi part that specifies fuel injection rule suspension per injection,
Further, the fuel injection section is characterized in that the length in the fuel Pl flow direction does not change regardless of the opening/closing operation of the valve member.

Note that the structure of this fuel metering section is, for example,
It is possible to change the form of the valve part H, or to change the form of the fuel passage (housing) in that part.

<Fl use/Effect> In this J, in-cylinder fuel system, during the transition period of injection when the valve member is displaced from the closed position to the closed position, the length of the fuel metering section in the flow direction is equal to the displacement of the valve member. As a result, the flow characteristics of the dynamic flow rate are stabilized and approach the measurement, making it possible to accurately grasp the dynamic flow rate, which was difficult to do in the past.

<Example> An example of the present invention will be described below based on the drawings.

Embodiment 1 FIG. 1 shows an embodiment of the cylinder combustion old injection system; 6 (LJ
FIG. 2 is a cross-sectional view showing the entire injector (2). This injector 2 is fixed at a position 122 with respect to the injector 2 shown in FIG.

As is clear from FIG. 1, this injector 2 includes a first housing member 4. Second housing member 6° guide member 8
and a seam 1 and a member 10, which are fixed to the phase n, and together constitute one housing 12. The first housing part) A4 and the second housing part 6 are crimped together through the O-ring 14, and the second housing part 6, the guide member 8 and the seats 1 to 10 are Fixed by welding.

Inside such a housing 12 is a rod-shaped valve member 16.
1, this valve member 16 has a two-part structure of a first valve part 18 and a second valve member 2o, which are butted against each other for the same purpose.

The first valve portion 18 is guided by the guide member 8 and the seat member 10, is held movable in the axial direction, and is provided with a valve head 22 at its tip.

The valve head 22 is formed in a conical shape that becomes larger toward the tip, and a shallow conical recess 24 is formed on its end face (valve end face) as shown in FIG. It remains in a ring shape on the outer periphery of the end face. Such a valve end face is exposed to the cylinder combustion chamber of the engine. At the tip of the seal l part iJ 10, there is a mode-specific jet nozzle 26 with a slightly smaller taper ratio than the valve head 22.
are formed so as to widen toward the outside, and four valve heads 22 are seated in these openings (valve seats 1 to 1) to form a liquid-tight seal portion 28.

As shown in FIGS. 1 and 2, a stopper 30 is attached to the rear end (inner end) of the first valve member 18 that protrudes rearward from the guide member 8, and a spring held by the stopper 30 A first spring 34 is disposed between the retainer 32 and the guide member 8 with a predetermined compressive preload. This spring 34 functions as a first spring means and always biases the first valve member 18 so that the valve head 22 closes the injection port 26.

The movement stroke S (Fig. 2) of the first valve part 418 is determined by the gab between the first valve part 30 and the guide member 8. As the moon 18 moves forward, the valve head 22 is lifted off the seat of the injection port 26, which is the closed position.

Returning to FIG. 1, the aforementioned second valve portion +J 20 extends toward the rear of the housing 12 and projects into the solenoid 36 that forms the main body of the electromagnetic drive means. The solenoid 36 is provided with a cylindrical core 38 with a flange, and the core 38 is crimped between the first housing part 4 and the second housing member 6 via the thread 4-0 at the pulling part. 1, which is sandwiched and fixed, is on the outside of the core 38.
A coil bobbin (hereinafter simply referred to as bobbin) 42 is fitted, and a coil 44 is wound around this bobbin 42. Also, the terminal (terminal) 13.1 is connected to the bobbin 42 via an adapter/16,46. /18 is installed, coil 4
4 is supplied with an excitation current from the outside via these terminals 48,48.

The second valve member 20 extends axially movably through 738, protrudes from the core 38, and has an armature 50 fixed to the rear end of the IC. With this armature 50:
The mechanical V gap with =1A 38 is adjusted by the spacer 40, and by energizing the coil 4, the armature 5
0 is attracted to the core 38, the second valve member 20
moves forward against the biasing force of the first spring 34, pushing the first valve portion 18 to the closed position.

This second valve portion +A 20 is always urged toward the first valve member 18 by a second spring 52 of C' serving as a second spring means. This second spring 52. is 7
The spring compression spring 1750 is installed between the spring clamp 1750 and the spring stopper vibration 54, and therefore exerts a biasing force on the first valve portion 18 in the opposite direction to that of the first spring 34. However, the spring force of the second spring 52 is much weaker than the spring force of the first spring 34, and rll (?/i
It plays the role of keeping the second valve part 20 always in a butt state with the first valve member 18 located at i'r. As a result, the spring force that urges the first valve member 18 to the closed position is equal to the spring force of the spring 34 minus that of the second spring 52. It is conceivable that spring means with a differential load pull the first valve part 18 in the closing direction lv. The degree of spring of the second spring 52 can be adjusted by adjusting the insertion amount of the first spring 54 into the first housing portion 4. After that, by caulking the first housing member 4 from the outside, the vibration 54 can be adjusted. The position of is fixed.

The amount of rearward movement of the second valve part 20 is regulated by stoppers (twins, referred to as Pax 1 to Tsuba); This Pax 1~Brim! 56 is armature 50
is fixed to the first housing member 4 facing the
The gap between the two is not smaller than the valve strike position of the first valve member 138. In other words, the pax 1 to the collar 56 do not hinder the closing movement of the first valve member 18, but function to prevent the second valve member 20 from moving away from the first valve member 18 and retreating excessively. Fulfill the purpose.

A fuel passage 60 is formed in the housing 12 to guide fuel from a fuel supply boat 58 formed at the rear end to the fuel injection port 26 at the front end, and this will be described in more detail.

Inside the supply boat 58, there are provided strainers 1 to 62 for capturing dirt and the like in the fuel, and the fuel that has passed through these strainers is
The passage section 64 leads to the vicinity of the armature 50. From here, the fuel passage bypasses the armature 50 and reaches the core 38.
and the bobbin 42. That is, as shown in FIGS. 5 and 6, on the inner peripheral surface forming the first passage 64 of the first housing portion 4, a four-piece hole 66 is formed in the axial direction, and this inner peripheral surface ni) j♂i 66 J: Richi ring (5
J, these four are being pressed in! A 66
If you burn it, 1 will pass through. Further, although the bobbin 42 is tightly fitted to the core 384, there are four pieces of wood on the inner circumference of the bobbin 42, as shown in FIG. M 70 is knee 1 no 138
These are the four trees mentioned above! far 6
6 and communicate with each other. In other words, these /I trees! The hanger 70 is a fuel passage formed between the a 38 and the bobbin 42, and the fuel flows very close to the inner periphery of the coil 44.

The four holes 70 of the bobbin 42 are connected to the four communication holes 72 formed in the 7 flange portion of the bobbin 42 and the spacer 4.
It communicates with a second passage 76 corresponding to the central space of the second housing member 6 through a central hole 74 of 0. As is clear from FIG. 2, this second passage 76 is connected to the four radial communication holes 8 formed in the guide part trA8 with respect to the third passage 78 running in the tkll direction in the central part of the guide part vU8.
0 is connected to J:ri.

Here, the first valve member 18 described above includes a rear valve guide part 82 formed at the rear end of the guide member 8 and an ICC vise valve guide 82 formed at the rear end of the seat member 10.
The axial movement 5 is guided at two locations, 4 and 4, but a high degree of guidance is achieved by the front valve guide section 84, which plays the main role in the guiding function. In other words, the members 91 to 10 are fluid-tightly fitted to the front end of the guide member 8, but the inner peripheral surface of the guide member 8 is As shown in FIG. The communicating hole 88 communicates with the center hole 89 of the seat member 10, and the first valve member 1
8, this part is designated as the small t\ portion 92. As a result,
A bypass fuel passage from the second passage 78 on the upstream side to the injection port 26 side by bypassing the front valve guide part 8/I (
90 (simply referred to as a bypass passage) is formed.

High II just before injection 126! The gap between the turtles (!J M
The claw portion 94 is formed, and the ? The PA of each injection 6i per AtAt cross-sectional area is determined3, and this part is shown in an enlarged scale in FIG. 4(a), which shows the valve closed state6.

The metering section 94 is provided with a cylindrical gap (consumption flow path) corresponding to the difference between the cross-sectional area of the fuel passage and the cross-sectional area of the valve member, and the length of the metering section in the flow direction is Ql.

In other words, the sea 1 member 10 is located between 51 and 94, and -CF
The valve head 22 of the first pulp part 18 has a constricted part 9 at its base.
5 is formed, and as a result, the ~th valve part jtA' 18
is d3 in the hanging part 9/I of 51, and the narrow part 95 and the small diameter part 92
The 01-1 portion of the first valve member 18 is formed by the cylindrical outer circumferential surface from G+÷J to 1-1 point between Three-
Even in the open state of the valve shown in FIG.
1: The squares and positional relationship of the E-+'' portion and the G14 portion are set so that they do not protrude forward from the point.

The injector as described above is fixed to the threaded portion 96 of the second housing portion 6 shown in FIG. 1 (see FIG. 9), and is used.

1) Solenoid 360 by energizing coil 4
) ll, IIl k-J, l'J 7' -? (750 Crab J 7' 38 d) When the suction occurs, the second valve member 20 moves forward and pushes the first valve member 18 to the closed position against the biasing force of the first spring 34, thereby causing the injection. Fuel is injected into the cylinder from the port 26. When the solenoid 36 is demagnetized, the first valve member 18 returns to the closed position due to the spring force of the first spring 34, and with this return operation, the second valve portion +A20 is pushed back, where the first and second valve members 18 and 20
Because of the two-part structure, the inertial mass of the first valve member 18 that closes the injection port 26 is sufficiently small compared to the mass of the movable parts as a whole. The bouncing when sitting is very small, and the fuel cutoff is good (-), which suppresses trailing sag (1).Furthermore, even after the first valve member 18 stops at the closed position, the second valve member 20 remains in place. Due to inertia □Second spring 5
I try to retreat while compressing 2, but Pax 1-8 brim 56 prevents Lα from retreating, and...
1 is separated from the first valve member 18 - (0, J is in a jagged butt state. 1; L, when the hull 1 member 20 moves backward 1, it is pushed back by the repulsive force of the second spring 52. and strongly hit the first valve member 1ε3, and the 110% opening 2
There is a risk that 6 will open 10), but this will be avoided.

Further, the valve end face of the first valve member 18 faces the combustion chamber in the cylinder, and since the concave portion 24 is formed, the fuel oil '11 drips from the injection L126. The droplets do not become as large as they would otherwise be, and the generation of soot is suppressed.

The fuel flows through the aforementioned fuel passage 60, and in L12 at the solenoid 36: 1, this fuel flows through the gap 70 between the a 38 and the pobin 42, and this fuel cools the oil 44. Therefore, a decrease in the magnetic attraction force due to an increase in electrical resistance due to heat generation is suppressed. The fuel detours through the bypass passage 90 having a cross-sectional area, and the flow resistance is smaller than that in the case where the guide portion 84 is also used as a separate fuel passage.

In addition, since the valve guide part 84 and the fl ff1 part 94 are separated, the valve guide part 84 is processed with a focus on the same 111111 bamboo as the first valve part + A' 18, and the hi quantity group part 94 is is 1 unit in the cross-sectional area of the flow path.
Since the machining required for 3 is J, it is easier for K2F to achieve 4T compared to the case where both parties are forced to perform bulky machining.

31k, as shown in FIGS. 4(a) and (b), the length in the flow direction when the valve is closed is 01,
If the length in the flow direction of the valve opening 11) is 02, then Pal,
Part 7 + 418 (7) Weird A;l “J” i
tl M Alf IX cM L;L','j L
/<, Q1=I)2 is maintained. If I change my fortune, the length of the measuring section A, (11 (, Q2) is the first valve section + A
The distance between 18 and 011 C- Sexually! As a result, the dynamic flow t1 during the transition period from the valve closed state to the open state becomes stable.

1st Example Figure 8 (a), (1)) shows four parts of the 2nd Example-J
-o In the combustion r1 claw part 94 of this example, the constriction part in the first valve member 18 is 4c<, and the M-N part between the small diameter part 92 and the valve head 22 is formed by the outer peripheral surface of the circle 16). - 10,000, Sea I, Undercut 1 to part 97 are installed on member 10, and the undercut 1 to part 97 is set: J'l D
26, a part of -1 is formed by the inner circumferential surface of the cylinder 3, a part of -1 and part of this part is M-N part J, and the valve is in the open state as shown in Fig. 33(b). (The N point of the first valve member 1F3 does not enter the front of the seat member 10 by 1 point.)
The dimensions and positional relationships of the parts h< have been determined.

In this embodiment, the valve 81 of the hanging portion 94 is closed 11.
1, the length Dl is equal to the lq length Q2 of the valve length 11,), and the total t6 part quality (distance between K-' l-1ilI!) is held constant regardless of whether the valve is opened or closed. , practically the same effect as the first embodiment is obtained.

The above description is literally an example, and the present invention is not limited to the description of this embodiment. Based on the knowledge of those skilled in the art, various modifications were made. Of course you can.

1 4. Simplified drawings Figures 1 to 8 show a first embodiment of the present invention. Figure 1 is an overall cross-section of an in-cylinder fuel device, which is the first embodiment. 2 is a partial sectional view of the tip side thereof, FIG. 3 is a Δ-A sectional view in FIG. 2, and FIG. 4(a) is an enlarged sectional view of the tip portion of FIG. 2 in the valve closed state. FIG. 4(b) is a large sectional view of 411 in the same valve open state, FIG. 5 is a partial sectional view of the central part in FIG. 1, and FIG. Fig. 7 is a cross-sectional view taken along the same line C-C. Fig. 8(a) and (b) show the main parts of the second embodiment of the present invention, and Fig. 8(a) is an enlarged cross-sectional view of the valve in the closed state. Figure 8(b) is an enlarged cross-sectional view of the valve in the open state. , Fig. 10 is an explanatory view of the operation of the engine. Fig. 11 (al is a sectional view of the main part in the valve closed state, and Fig. 11 (b) is a sectional view of the main part in the valve open state. The cross-sectional view and FIG. 12 are η graphs showing the fuel injection canopy M during the valve opening operation process of the conventional example. (A 20... Second bulge member 24... Fourth part 26... Fuel injection ['' 34... First spring 3G... Solenoid 38...] A42... Coil bobbin 44...・] Coil 0...Armadure 52...Second spring 56...Pax 1-flange 60...Fuel passages 70, 86...Full 80, 88...Communication hole 94...Fuel leak Year part 95... Waist part 91... Undercut 1 part 3 JP-A-3 50378 (8) Satsuma throat fan

Claims (1)

[Scope of Claims] An in-cylinder fuel injection device for injecting fuel into the cylinders of an engine, comprising a housing having a fuel passage formed therein, and a fuel injection port of the housing that is opened and closed from the outside of the housing. a valve member that is moved between a closed position and a closed position, a spring means that constantly biases the valve member to a closed position, and an electromagnetic drive means that moves the valve member to an open position against the biasing force of the spring means. , provided in the fuel passage in front of the fuel injection port, giving a constant flow passage cross-sectional area corresponding to the difference between the cross-sectional area of the fuel passage and the cross-sectional area of the valve member over a predetermined length in the flow direction, and injecting and a fuel metering section that defines the amount of fuel to be injected per injection, and the fuel metering section has a structure in which the length in the fuel flow direction does not change regardless of the opening/closing operation of the valve member. In-cylinder fuel injection system.