Title of invention: Fuel injection valve and port injection type internal combustion engine
Technical field
[0001]
The present invention relates to a fuel injection valve that injects fuel into an intake port of an internal combustion engine, and a port injection type internal combustion engine provided with such a fuel injection valve.
Background technology
[0002]
The control device for an internal combustion engine disclosed in Patent Document 1 includes two intake ports composed of straight ports and two fuel injection valves in which the fuel spray shape is set asymmetrically with respect to the central axis, and fuel injection is provided. Occasionally, of the fuel injected from the two fuel injection valves, the injection amount injected between the stems of the intake valve is set to be larger than the injection amount injected outside the stem of the intake valve, and the fuel is injected. The cross-sectional shape of the spray that is broken in a plane perpendicular to the spray direction is C-shaped, and one notch provided in the cross-sectional shape of the spray is configured to match the position of the stem.
Prior art literature
Patent documents
[0003]
Patent Document 1: Japanese Unexamined Patent Publication No. 2012-036757
Outline of the invention
Problems to be solved by the invention
[0004]
By the way, if the fuel spray is distributed in a part of the space in the intake port and the spray cross section is non-uniform, the premixing of the fuel spray and air in the intake port becomes non-uniform, and the in-cylinder mixing is performed. There was a problem that the homogeneity of the air deteriorated, leading to an increase in unburned fuel, occurrence of knocking, and deterioration of flammability.
[0005]
The present invention has been made in view of conventional circumstances, an object of which is to provide a fuel injection valve and a port injection internal combustion engine capable of promoting premixing of fuel spray and air in an intake port. It is in.
Means to solve the problem
[0006]
Therefore, the fuel injection valve according to the present invention is, as one aspect, a fuel injection valve that injects fuel into the intake port of the internal combustion engine, and the breakup position of the fuel spray injected from the fuel injection valve is the intake. It is set upstream from the valve.
Further, the port injection type internal combustion engine according to the present invention is, as one aspect, a port injection type internal combustion engine provided with a fuel injection valve for injecting fuel into the intake port of the internal combustion engine, and is injected from the fuel injection valve. The break-up position of the fuel spray is set upstream from the intake valve, and the cross-sectional shape of the fuel spray in the cross section perpendicular to the injection direction of the fuel spray at a predetermined position based on the break-up position is the shape of the intake port. It is a reduced cross-sectional shape.
Effect of the invention
[0007]
According to the above invention, premixing of fuel spray and air in the intake port can be promoted, and the homogeneity of the in-cylinder air-fuel mixture can be improved.
A brief description of the drawing
[0008]
[Fig. 1] Fig. 1 is a schematic configuration diagram of a port injection type internal combustion engine.
FIG. 2 is a vertical sectional view of a fuel injection valve.
[Fig. 3] Fig. 3 is an enlarged vertical cross-sectional view of the tip of a fuel injection valve.
FIG. 4 is a top view of an orifice plate of a fuel injection valve.
[Fig. 5] Fig. 5 is a schematic view showing a state in which a fuel injection valve is mounted on an intake port.
FIG. 6 is a diagram for explaining the correlation between the injection angle of the fuel injection valve and the inner wall of the intake port.
[Fig. 7] Fig. 7 is a diagram showing the distribution state of fuel spray in the intake port.
FIG. 8 is a diagram showing a cross-sectional shape of a fuel spray when the cross section of an intake port is a horizontally long elliptical shape.
FIG. 9 is a diagram showing a cross-sectional shape of a fuel spray when the cross section of the intake port is circular.
FIG. 10 is a diagram showing a cross-sectional shape of a fuel spray when the cross section of an intake port is a vertically long elliptical shape.
FIG. 11 is a diagram showing the aspect ratio of the cross section of the intake port and the aspect ratio of the cross section of the fuel spray.
FIG. 12 is a diagram showing the correlation between the aspect ratio of the cross section of the intake port and the aspect ratio of the cross section of the fuel spray.
FIG. 13 is a diagram showing a cross section of an intake port in a straight port.
FIG. 14 is a diagram showing a cross section of an intake port at a Siamese port.
FIG. 15 is a diagram showing the correlation between the breakup position Ls and the number of particles, the average particle size, and the average velocity.
FIG. 16 is a diagram showing a predetermined position LP according to a breakup position Ls and an average particle size and an average velocity at the breakup position Ls.
Embodiment for carrying out the invention
[0009]
An embodiment of the present invention will be described below.
FIG. 1 is a schematic configuration diagram of the internal combustion engine 101.
The internal combustion engine 101 is a spark ignition gasoline engine mounted as a drive source in an automobile, and is, for example, an in-line 4-cylinder engine.
However, the number of cylinders of the internal combustion engine 101 is not limited to 4 cylinders, and the internal combustion engine 101 may be a horizontally opposed type or a V type.
[0010]
The internal combustion engine 101 includes an ignition device 104, a fuel injection valve 105, and the like.
The fuel injection valve 105 is attached to the intake port 102 upstream of the intake valve 119 so as to face the intake valve 119, and injects fuel into the intake port 102.
That is, the internal combustion engine 101 in FIG. 1 is a so-called port injection type internal combustion engine.
[0011]
The ignition device 104 is composed of an ignition plug, an ignition coil, a power transistor, and the like, and ignites and burns the air-fuel mixture in the combustion chamber 110.
The flow rate of the air that has passed through the air cleaner 107 is adjusted by the throttle valve 108a of the electronically controlled throttle 108, and is sucked into the combustion chamber 110 through the intake valve 119 together with the fuel injected from the fuel injection valve 105.
[0012]
The electronically controlled throttle 108 is a device that opens and closes the throttle valve 108a by the throttle motor 108b, and includes a throttle opening sensor 108c that outputs a throttle opening signal TPS that is information on the opening of the throttle valve 108a.
By detecting the protrusion of the ring gear 114, the crank angle sensor 106 outputs a crank angle signal CA, which is a pulse signal that rises at each predetermined rotation angle of the crank shaft 117.
[0013]
The flow rate detection device 109 is arranged upstream of the electronically controlled throttle 108 and outputs an intake air flow rate signal QAR which is information on the intake air flow rate of the internal combustion engine 101.
Further, the catalyst converter 112 arranged in the exhaust pipe 103 of the internal combustion engine 101 has a built-in ternary catalyst to purify the exhaust of the internal combustion engine 101.
[0014]
The air fuel ratio sensor 111 is arranged in the exhaust pipe 103 upstream of the catalytic converter 112, and outputs an air fuel ratio signal RABF which is information on the exhaust air fuel ratio according to the oxygen concentration in the exhaust.
Further, the exhaust temperature sensor 116 is arranged in the exhaust pipe 103 upstream of the catalytic converter 112, and outputs an exhaust temperature signal TEX which is information on the exhaust temperature [° C.] at the inlet of the catalytic converter 112.
[0015]
Further, the water temperature sensor 118 outputs a cooling water temperature signal TW which is information on the temperature [° C.] of the cooling water in the cooling water jacket of the internal combustion engine 101.
The engine control device 113 is an electronic control device including a microcomputer including an MPU (Microprocessor Unit) 126, a ROM (Read Only Memory) 127, and a RAM (Random Access Memory) 128.
The engine control device 113 performs a calculation based on the acquired information, outputs the calculation result to the ignition device 104, the fuel injection valve 105, the electronically controlled throttle 108, etc., and serves as a control unit for controlling the operation of the internal combustion engine 101. Has a function.
[0016]
The engine control device 113 acquires the throttle opening signal TPS, the intake air flow rate signal QAR, the crank angle signal CA, the air fuel ratio signal RABF, the exhaust temperature signal TEX, and the like, which are output by each of the above-mentioned sensors.
Then, the engine control device 113 calculates the ignition timing, the fuel injection amount, and the like based on the acquired various signals, outputs the ignition control signal for controlling the ignition timing to the ignition device 104, and controls the fuel injection amount. A pulse signal (in other words, an air fuel ratio control signal) is output to the fuel injection valve 105.
[0017]
The engine control device 113 has an analog input circuit 120, an A / D conversion circuit 121, a digital input circuit 122, an output circuit 123, and I in order to input and output measurement results of various sensors and an operation amount to be output to various devices. A / O circuit 124 is provided.
The analog input circuit 120 performs acquisition processing of analog detection signals such as intake air flow rate signal QAR, throttle opening signal TPS, air fuel ratio signal RABF, exhaust temperature signal TEX, and cooling water temperature signal TW.
[0018]
The analog detection signal acquired by the analog input circuit 120 is supplied to the A / D conversion circuit 121, converted into a digital signal, and output on the bus 125.
Further, the crank angle signal CA or the like, which is a digital detection signal acquired and processed by the digital input circuit 122, is output on the bus 125 via the I / O circuit 124.
[0019]
MPU126, ROM127, RAM128, timer / counter (TMR / CNT) 129, etc. are connected to the bus 125. Then, the MPU 126, the ROM 127, and the RAM 128 exchange data via the bus 125.
A clock signal is supplied to the MPU 126 from the clock generator 130, and the MPU 126 executes various calculations and processes in synchronization with the clock signal.
[0020]
The ROM 127 is composed of, for example, an EEPROM (Electrically Erasable Programmable Read-Only Memory) capable of erasing and rewriting data, and stores a program for operating the engine control device 113, setting data, initial values, and the like.
The information stored in ROM 127 is read into RAM 128 and MPU 126 via bus 125.
[0021]
The RAM 128 is used as a work area for temporarily storing the calculation result and the processing result by the MPU 126.
The timer / counter 129 is used for measuring time and measuring various times.
After the operation amount signals such as the ignition control signal and the air fuel ratio control signal, which are the calculation results by the MPU 126, are output on the bus 125, the ignition device 104 and the fuel injection valve are output from the output circuit 123 via the I / O circuit 124. It is supplied to 105, an electronically controlled throttle 108, and the like.
[0022]
FIGS. 2-FIG. 4 show an aspect of the structure of the fuel injection valve 105.
FIG. 2 is a vertical sectional view showing the overall configuration of the fuel injection valve 105, FIG. 3 is an enlarged vertical sectional view of the tip of the fuel injection valve 105, and FIG. 4 is a top view of an orifice plate 20 having an injection hole.
The fuel injection valve 105 has a structure in which a nozzle body 2 and a valve body 6 are housed in a pipe 13 and the valve body 6 is reciprocated by an electromagnetic coil 11.
[0023]
The fuel injection valve 105 includes a magnetic yoke 10 surrounding the electromagnetic coil 11, a core 7 located at the center of the electromagnetic coil 11, a valve body 6, a valve seat surface 3 on which the valve body 6 is seated, and a valve body 6. A fuel injection chamber 4 into which fuel flows through the gap between the valve seat surface 3 and an orifice plate 20 arranged downstream of the fuel injection chamber 4 and having a plurality of injection holes 23a, 23b, 23c are provided. ..
Further, a spring 8 for pressing the valve body 6 against the valve seat surface 3 is provided at the center of the core 7, and the elastic force of the spring 8 is adjusted by the spring adjuster 9.
[0024]
When the electromagnetic coil 11 is not energized, the valve body 6 is seated on the valve seat surface 3, and fuel injection is not performed from the injection holes 23a, 23b, 23c.
On the other hand, when the electromagnetic coil 11 is energized, the valve body 6 moves until it comes into contact with the end face of the core 7 facing the valve body 6 due to the electromagnetic force generated by the electromagnetic coil 11.
Then, due to the movement of the valve body 6, a gap is created between the valve body 6 and the valve seat surface 3, a fuel passage is opened, and fuel is injected from the injection holes 23a, 23b, 23c.
[0025]
The fuel injection valve 105 is provided with a fuel passage 12 having a filter 14 at the inlet portion.
Further, the outer periphery of the fuel injection valve 105 is covered with a resin mold 15.
[0026]
Next, the structure of the nozzle body 2 will be described in detail with reference to FIG.
The upper surface 20a of the orifice plate 20 is in contact with the lower surface 2a of the nozzle body 2, and the outer periphery of the contact portion is laser-welded and fixed to the nozzle body 2.
[0027]
A fuel introduction hole 5 having a diameter smaller than the diameter φS of the seat portion 3a of the valve seat surface 3 is provided at the lower end portion of the nozzle body 2.
The valve seat surface 3 has a conical shape, and fuel is introduced in the center of the downstream end. The hole 5 is formed.
[0028]
The valve seat surface 3 and the fuel introduction hole 5 are formed so that the center line of the valve seat surface 3 and the center line of the fuel introduction hole 5 coincide with the valve axis X.
The fuel introduction hole 5 forms an opening in the lower surface 2a of the nozzle body 2 that communicates with the central chamber 24 of the orifice plate 20.
[0029]
Next, the structure of the orifice plate 20 will be described in detail.
The central chamber 24 is a concave portion provided on the upper surface 20a of the orifice plate 20.
[0030]
The central chamber 24 is connected to four swivel passages 21a, 21b, 21c, 21d arranged in the circumferential direction and extending radially toward the outer periphery.
The downstream end of the swivel passage 21a communicates with the swivel chamber 22a, the downstream end of the swivel passage 21b communicates with the swivel chamber 22b, and the downstream end of the swivel passage 21c communicates with the swivel chamber 22c. The downstream end of 21d communicates with the swivel chamber 22d.
[0031]
The wall surfaces of the swivel chambers 22a, 22b, 22c, and 22d are formed so that the curvature gradually increases from the upstream to the downstream. The swivel chambers 22a, 22b, 22c, and 22d form a spiral fuel passage that gradually approaches the center from the upstream to the downstream.
Injection holes 23a, 23b, 23c, 23d are opened at the centers of the swivel chambers 22a, 22b, 22c, 22d, respectively.
Further, in the orifice plate 20 shown in FIG. 4, the pair of the swivel passage 21a and the swivel passage 21b and the set of the swivel passage 21c and the swivel passage 21d are arranged line-symmetrically with the diameter of the orifice plate 20 in between. Will be done. Further, the angle formed by the turning passage 21a and the turning passage 21b, and the angle formed by the turning passage 21c and the turning passage 21d are set to be less than 90 deg, respectively.
[0032]
According to the fuel injection valve 105 described above, the fuel spray injected from the injection holes 23a, 23b, 23c, 23d through the swivel chambers 22a, 22b, 22c, 22d provided in the orifice plate 20 has a spiral flow. Amplifies atomization.
That is, the swivel chambers 22a, 22b, 22c, 22d, the swivel passages 21a, 21b, 21c, 21d, and the injection holes 23a, 23b, 23c, 23d constitute the atomization promotion mechanism.
[0033]
However, the atomization promotion mechanism is not limited to the mechanism that makes the fuel spray a spiral flow by the swirling chambers 22a, 22b, 22c, 22d. For example, known atomization promoting mechanisms such as a mechanism for colliding an air flow with a fuel spray, a mechanism for forming a spiral groove in the valve body of a fuel injection valve, and a mechanism for heating fuel before being injected from an injection hole. It can be adopted as appropriate.
Further, the arrangement and number of swirling passages in the orifice plate 20 are not limited to those in FIG. 4, but can be appropriately changed in order to obtain a desired spray shape.
For example, four turning passages 21a, 21b, 21c, 21d can be arranged at equal intervals in the circumferential direction of the central chamber 24, and the angles formed by the adjacent turning passages 21 can all be 90deg. It is also possible to set the swivel passages 21a, 21b, 21c, 21d and the injection holes 23a, 23b, 23c, 23d to other than four.
[0034]
Next, the injection characteristics of the fuel injection valve 105, in detail, the spray shape, the spray angle, the directivity, and the like will be described.
5 and 6 are views showing a state in which the fuel injection valve 105 is mounted on the intake port 102 and a spray angle of the fuel injection valve 105.
[0035]
The fuel injection valve 105 is attached to the intake port 102 so as to face the direction of the intake valve 119.
Specifically, the fuel injection valve 105 is attached to the peripheral wall of the intake port 102 so that the extension line of the axis of the fuel injection valve 105 passes near the center of the umbrella portion 119c of the intake valve 119.
The axis of the fuel injection valve 105 is the axis connecting the injection direction of the outer surface of the orifice plate 20 through the center of the orifice plate 20 of the fuel injection valve 105 or the center of the valve body 6, or the central axis of the spray pattern. can do.
[0036]
Further, the cross-sectional shape of the fuel spray in the cross section perpendicular to the injection direction of the fuel spray at the predetermined position LP at which the directivity of the fuel spray injected from the fuel injection valve 105 is sufficiently lowered (AA cross section in FIG. 5) The injection characteristics are set so that the cross-sectional shape of the intake port 102 is reduced to a similar shape.
However, the cross-sectional shape of the fuel spray and the cross-sectional shape of the intake port 102 are not limited to similar shapes that overlap each other by scale conversion.
That is, the cross-sectional shape of the intake port 102 and the cross-sectional shape of the fuel spray in the cross section perpendicular to the injection direction of the fuel spray at the predetermined position LP differ in the width dimension in each of the two axes orthogonal to each other, and the intake air is taken. It can be set so that the longitudinal direction of the cross section of the port 102 and the longitudinal direction of the cross section of the fuel spray match.
For example, the cross-sectional shape of the fuel spray and the cross-sectional shape of the intake port 102 are not similar, but both are elliptical, and the longitudinal direction of the cross section of the fuel spray and the longitudinal direction of the cross section of the fuel spray are the same direction. It is not a requirement that the cross-sectional shape of the fuel spray and the cross-sectional shape of the intake port 102 are similar to each other in the scale conversion.
[0037]
Further, the virtual extension region extending the region within the spray angle θ of the fuel spray is set to include the inner wall of the intake port 102 closer to the intake valve 119 than the predetermined position LP (see FIG. 6). ..
In other words, assuming that the fuel spray has a penetrating force that reaches the intake valves 119a and 119b while maintaining the directivity, the fuel spray is applied to the inner walls of the intake ports 102a and 102b downstream from the predetermined position LP. It is set to the spray angle that collides.
[0038]
FIG. 7 is a diagram showing the distribution state of the fuel spray of the fuel injection valve 105 in the intake port 102.
That is, in the region where the fuel spray closer to the fuel injection valve 105 than the predetermined position LP and the predetermined position LP has directionality, the cross section of the fuel spray is included in the cross section of the intake port 102, and the fuel spray is included in the intake port. Prevents collision with the inner wall of 102. Further, in the region where the directivity of the fuel spray downstream from the predetermined position LP is sufficiently lowered, the injection characteristics of the fuel injection valve 105 so that the fuel spray can be distributed as widely as possible in the intake port 102. , In detail, the spray angle, directivity, etc. are set.
[0039]
The predetermined position LP is a value indicating the distance [mm] from the injection holes 23a, 23b, 23c of the fuel injection valve 105 along the axis (central axis of spraying) of the fuel injection valve 105.
Further, the predetermined position LP is a position set based on the breakup position Ls of the fuel spray, and will be described in detail later.
[0040]
FIG. 8-10 is a diagram showing the correlation between the cross-sectional shape of the fuel spray at the predetermined position LP and the cross-sectional shape of the intake port 102.
Here, the internal combustion engine 101 includes two intake ports 102a and 102b and two intake valves 119a and 119b for each cylinder.
In the present application, the arrangement direction of the intake ports 102a and 102b (intake valves 119a and 119b) is set to the lateral direction (X-axis direction), and the directions orthogonal to the arrangement direction of the intake ports 102a and 102b (intake valves 119a and 119b). Is the vertical direction (Y-axis direction).
[0041]
In FIG. 8, the cross-sectional shape of the intake ports 102a and 102b is such that the spray cross-sectional length (maximum horizontal width) in the horizontal direction (X-axis direction) is larger than the spray cross-sectional length (maximum vertical width) in the vertical direction (Y-axis direction). An example shows an internal combustion engine 101 set in a long, horizontally long oval shape (long oval shape in the X-axis direction).
As described above, when the cross-sectional shape of the intake ports 102a and 102b is a horizontally long elliptical shape (an elliptical shape long in the X-axis direction), the cross-sectional shape of the fuel spray at the predetermined position LP is the cross-sectional shape of the intake ports 102a and 102b. Is set to a horizontally long elliptical shape (a long elliptical shape in the X-axis direction).
[0042]
In FIG. 9, the cross-sectional shape of the intake ports 102a and 102b is circular in which the spray cross-sectional length (maximum horizontal width) in the horizontal direction (X-axis direction) and the spray cross-sectional length in the vertical direction (Y-axis direction) are substantially equivalent. The set internal combustion engine 101 is illustrated.
As described above, when the cross-sectional shape of the intake ports 102a and 102b is circular, the cross-sectional shape of the fuel spray at the predetermined position LP is set to a circular shape obtained by reducing the cross-sectional shape of the intake ports 102a and 102b.
[0043]
In FIG. 10, the cross-sectional shape of the intake ports 102a and 102b is such that the spray cross-sectional length (maximum horizontal width) in the horizontal direction (X-axis direction) is larger than the spray cross-sectional length (maximum vertical width) in the vertical direction (Y-axis direction). An example is an internal combustion engine 101 having a short, vertically long elliptical shape (an elliptical shape long in the Y-axis direction).
As described above, when the cross-sectional shape of the intake ports 102a and 102b is a vertically long elliptical shape (an elliptical shape long in the Y-axis direction), the cross-sectional shape of the fuel spray at the predetermined position LP is the cross-sectional shape of the intake ports 102a and 102b. Is set to a reduced vertically long elliptical shape (in other words, an elliptical shape long in the Y-axis direction).
[0044]
That is, in the internal combustion engine 101, the aspect ratio of the cross-sectional shape of the fuel spray at the predetermined position LP is equivalent to the aspect ratio of the cross-sectional shape of the intake ports 102a and 102b, that is, the cross-sectional shape of the fuel spray is the intake port 102a. , 102b is set to have a similar shape with a reduced cross-sectional shape.
[0045]
Here, as shown in FIG. 11, the length of the cross-sectional shape of the fuel spray in the vertical direction (Y-axis direction) is represented by Sy, and the length in the horizontal direction (X-axis direction) is represented by Sx, and the intake ports 102a and 102b. It is assumed that the length of the cross-sectional shape in the vertical direction (Y-axis direction) is represented by Py and the length in the horizontal direction (X-axis direction) is represented by Px.
At this time, the aspect ratio of the cross-sectional shape of the fuel spray is Sy / Sx, and the aspect ratio of the cross-sectional shapes of the intake ports 102a and 102b is Py / Px.
[0046]
FIG. 12 shows the correlation between the aspect ratio of the cross-sectional shape of the fuel spray and the aspect ratio of the cross-sectional shape of the intake ports 102a and 102b.
When the cross-sectional shape of the intake ports 102a and 102b shown in FIG. 8 is an elliptical shape that is long in the horizontal direction (X-axis direction), the aspect ratio Py / Px is a value less than 1, and the vertical and horizontal cross-sectional shapes of the fuel spray are obtained. The spray shape is also set so that the ratio Sy / Sx has the same value as the aspect ratio Py / Px.
[0047]
Further, when the cross-sectional shape of the intake ports 102a and 102b shown in FIG. 9 is circular, the aspect ratio Py / Px is 1, and the aspect ratio Sy / Sx of the cross-sectional shape of the fuel spray is also sprayed. The shape is set.
Further, when the cross-sectional shape of the intake ports 102a and 102b shown in FIG. 10 is an elliptical shape long in the vertical direction (Y-axis direction), the aspect ratio Py / Px becomes a value exceeding 1, and the cross-sectional shape of the fuel spray The spray shape is also set so that the aspect ratio Sy / Sx of is also the same value as the aspect ratio Py / Px.
[0048]
Next, the difference in the specific position of the aspect ratio Py / Px of the intake port 102 due to the difference in the shape of the intake port 102 will be described.
FIG. 13 shows a specific position of the aspect ratio Py / Px of the intake ports 102a and 102b when the intake ports 102a and 102b of the internal combustion engine 101 are straight ports, respectively.
The straight port has a shape in which each of the intake ports 102a and 102b of the internal combustion engine 101 extends to the intake valves 119a and 119b without branching from the installation position of the fuel injection valve 105.
[0049]
Here, the internal combustion engine 101 includes a fuel injection valve 105a for injecting fuel into the intake port 102a and a fuel injection valve 105a for injecting fuel into the intake port 102b as the fuel injection valve 105.
When the intake ports 102a and 102b of the internal combustion engine 101 are straight ports, the aspect ratio Py / Px of the cross-sectional shape of the intake ports 102a and 102b is set to the vertical length Py of the intake ports 102a and 102b at the predetermined position LP. It is the ratio with the lateral length Px of the intake ports 102a and 102b at the predetermined position LP.
[0050]
FIG. 14 shows a specific position of the aspect ratio Py / Px of the intake port 102 when the intake port 102 of the internal combustion engine 101 is a siamese port (siamese type).
The siamese port has a shape in which the intake port 102 of the internal combustion engine 101 branches into two intake ports 102a and 102b at a branch portion 102c in the middle, and further.In the example of FIG. 14, the branch portion 102c is set at the installation position of the fuel injection valve 105 and downstream of the predetermined position LP.
[0051]
Here, as the fuel injection valve 105, the internal combustion engine 101 has a fuel injection valve 105a for injecting fuel into the intake port 102a and a fuel injection valve 105a for injecting fuel into the intake port 102b upstream from the branch portion 102c. It is arranged in each of the intake ports 102 of.
In the case of the Siamese port, since the LP at the predetermined position is upstream of the branch portion 102c, the lateral length Px of the cross section of the intake port 102 is set to the intake port after branching closer to the intake valves 119a and 119b than the branch portion 102c. The lateral lengths of 102a and 102b are set respectively.
[0052]
Next, the predetermined position LP will be described in detail.
In the internal combustion engine 101, the spray characteristics are set so that the breakup position Ls of the fuel injection valve 105 is upstream of the intake valves 119a and 119b.
The break-up position Ls is a position where the shape of the fuel spray begins to be disturbed due to the weakening of the directivity of the spray particles from the shape of the fuel spray arranged in a conical shape immediately after injection.
[0053]
FIG. 15 shows the correlation between the distance from the injection hole (injection point) of the fuel injection valve 105 and the number of particles per unit volume of the fuel spray, the average particle size, and the average velocity.
From the measurement results of particle size distribution, particle density, and particle velocity by laser diffraction confusion method, microscopic method, etc., it is possible to quantify the number of particles, particle size, and velocity according to the distance from the injection hole.
The particle size of the spray is generally quantified by the Sauter average particle size (SMD or D32), but the number average diameter (D10), the median diameter (D50), and the 90% particle size (D90) are used. Can be quantified using.
[0054]
The breakup position Ls is a unit of fuel spray with respect to a change in distance when the number of particles per unit volume of fuel spray, the average particle size, and the average speed are obtained for each distance from the injection hole of the fuel injection valve 105. It can be defined as a position where the number of particles per volume becomes a maximum value, a position where the average particle size becomes a minimum value with respect to a change in distance, or a position where the average speed becomes a predetermined speed or less.
That is, the region after the break-up position Ls is a region where the directivity of the fuel spray is sufficiently lowered, and in such a region, the fuel spray floats in the intake ports 102a and 102b toward the intake valve 119. It will flow.
[0055]
Therefore, as shown in FIG. 6, the inner wall of the intake port 102 closer to the intake valve 119 than the breakup position Ls is included in the virtual extension region extending the region within the range of the spray angle θ of the fuel spray. Also, the fuel spray can be widely distributed inside the intake ports 102a and 102b while suppressing the adhesion of fuel to the inner walls of the intake ports 102a and 102b.
If the fuel is sprayed at a wide angle so that the fuel spray collides with the inner walls of the intake ports 102a and 102b before the breakup position Ls, the fuel spray can be widely distributed in the intake ports 102a and 102b, but the intake air is taken. Fuel adhesion to the inner walls of ports 102a and 102b increases.
[0056]
On the other hand, if the spray is spread to the vicinity of the inner walls of the intake ports 102a and 102b before the break-up position Ls, the directivity of the fuel spray is sufficiently lowered after that, so that the fuel spray is made in the intake ports 102a and 102b. Can be suppressed from adhering to the inner walls of the intake ports 102a and 102b downstream from the breakup position Ls while widely distributing.
However, since the penetration force of the fuel spray is a force that correlates with the multiplication value of the diameter of the fuel spray particles and the spray rate, the fuel spray maintains a certain degree of directivity at the breakup position Ls, and the breakup occurs. Even if the position Ls is used as the reference position for the injection characteristics, it may not be possible to sufficiently suppress the adhesion of fuel to the inner walls of the intake ports 102a and 102b.
[0057]
Therefore, the reference position for spray formation is based on the break-up position Ls, and further, the average particle size and average speed at the break-up position Ls, in other words, the penetrating force of the fuel spray at the break-up position Ls. The predetermined position LP is set as.
FIG. 16 shows the setting characteristics of the predetermined position LP based on the break-up position Ls and the average particle size and the average velocity at the break-up position Ls.
[0058]
The horizontal axis in FIG. 16 is the breakup position Ls.
Further, the vertical axis of FIG. 16 is a value obtained by multiplying the average particle size at the breakup position Ls and the average velocity at the breakup position Ls, and is a value that correlates with the penetration force of the fuel spray at the breakup position Ls. Is.
[0059]
Here, the farther the break-up position Ls is from the injection hole of the fuel injection valve 105, the farther the predetermined position LP is from the injection hole of the fuel injection valve 105, and the average particle size at the break-up position Ls. The larger the multiplication value with the average speed, the farther the predetermined position LP is set from the injection hole of the fuel injection valve 105.
In other words, even if the breakup position Ls is the same, if the product of the average particle size and the average velocity at the breakup position Ls, that is, if the penetration force is large, the predetermined position LP is changed to a farther position.
[0060]
For example, when the break-up position Ls is set to the predetermined position LP, if the average particle size and / or the average speed at the break-up position Ls is large, the cross-sectional shape of the fuel spray at the predetermined position LP can be changed to the intake ports 102a and 102b. Even if the cross-sectional shape of the above is set to a reduced shape, the fuel spray maintains the directivity even after the predetermined position LP, so that the fuel spray may collide with and adhere to the inner walls of the intake ports 102a and 102b.
Therefore, when the average particle size and / or the average velocity at the break-up position Ls is large and the directivity is maintained, the predetermined position LP is changed to a farther position, and the cross-sectional shape of the fuel spray is the intake port at the predetermined position LP. The injection characteristics are set so as to be included in the cross sections of 102a and 102b.
[0061]
As a result, while expanding the spray cross section at the predetermined position LP as much as possible, it is possible to prevent the fuel spray from colliding with and adhering to the inner walls of the intake ports 102a and 102b after the predetermined position LP, and also, the intake air after the predetermined position LP. The fuel spray can be evenly distributed in the ports 102a and 102b.
Therefore, the fuel spray in the intake ports 102a and 102b and the premixing of air are made uniform to improve the homogeneity of the in-cylinder air-fuel mixture, which has the effects of reducing unburned fuel, suppressing knocking, and improving flammability. ..
[0062]
The technical ideas described in the above embodiments can be used in combination as appropriate as long as there is no inconsistency.
Further, although the content of the present invention has been specifically described with reference to a preferred embodiment, it is obvious that a person skilled in the art can adopt various modifications based on the basic technical idea and teaching of the present invention. Is.
[0063]
For example, it is possible to set the virtual extension region extending the region within the spray angle of the fuel spray so as not to include the inner walls of the intake ports 102a and 102b closer to the intake valves 119a and 119b than the predetermined position LP.
Also in this case, the break-up position Ls of the fuel spray injected from the fuel injection valve 105 is set to be in the intake ports 102a and 102b, and the fuel spray is performed at the predetermined position LP based on the break-up position Ls. If the cross-sectional shape of the fuel spray in the cross section perpendicular to the injection direction is set to a similar shape obtained by reducing the cross-sectional shape of the intake ports 102a and 102b, the intake port 102a will be after the directivity of the fuel spray is sufficiently lowered. , The fuel spray can be widely diffused in the 102b, and the premixing of the fuel spray and the air in the intake port 102 can be made uniform.
[0064]
Further, in the internal combustion engine 101 provided with the fuel injection valve 105, the injection end timing by the fuel injection valve 105 can be set before the intake top dead point.
If the injection end timing by the fuel injection valve 105 is set before the intake top dead point, that is, before the flow of intake air toward the inside of the cylinder occurs, the fuel spray injected from the fuel injection valve 105 is sent into the intake ports 102a and 102b. The premixed gas can be sucked into the cylinder after being widely diffused in the cylinder to equalize the premixing between the fuel spray and the air.
[0065]
Further, in the present application, the fact that the cross-sectional shape of the fuel spray is a shape obtained by reducing the cross-sectional shape of the intake port means that the aspect ratio of the cross section of the fuel spray is substantially the same as the aspect ratio of the cross section of the intake port. It does not require that the shapes match perfectly by showing, enlarging or reducing.
Further, the fact that the cross-sectional shape of the fuel spray is a similar shape obtained by reducing the cross-sectional shape of the intake port 102 indicates that the cross-sectional shapes of each other overlap each other by scale conversion without rotational movement, and one of them is a vertically long elliptical shape (one is a vertically long elliptical shape. In other words, it does not include the case where it is an ellipse long in the Y-axis direction) and the other is a horizontally long ellipse (in other words, an ellipse long in the X-axis direction).
[0066]
Further, in the internal combustion engine 101 shown in FIG. 14, in which the intake port 102 branches into two intake ports 102a and 102b downstream of the fuel injection valve 105, the fuel injection valve 105 is provided in each intake port 102a and 102b, respectively. Further, one fuel injection valve 105 for injecting in two directions toward each of the intake ports 102a and 102b can be provided.
Further, the predetermined position LP can be set to the break-up position Ls, and the predetermined position LP can be set based on the break-up position Ls and the average particle size at the break-up position Ls, and the break-up position Ls. And the average speed at the breakup position Ls, the predetermined position LP can be set.
Description of the sign
[0067]
101 ... internal combustion engine, 102 ... intake port, 105 ... fuel injection valve, 119 ... intake valve
The scope of the claims
[Claim 1]
A fuel injection valve that injects fuel into the intake port of an internal combustion engine.
The breakup position of the fuel spray injected from the fuel injection valve is set upstream from the intake valve.
Fuel injection valve.
[Claim 2]
The cross-sectional shape of the intake port and the cross-sectional shape of the fuel spray in the cross section perpendicular to the injection direction of the fuel spray at a predetermined position based on the breakup position are the width dimensions in each of the two axes orthogonal to each other. Is different,
The longitudinal direction of the cross section of the intake port is set to match the longitudinal direction of the cross section of the fuel spray.
The fuel injection valve according to claim 1.
[Claim 3]
The cross-sectional shape of the fuel spray in the cross section perpendicular to the injection direction of the fuel spray at a predetermined position based on the break-up position is a shape obtained by reducing the cross-sectional shape of the intake port.
The fuel injection valve according to claim 1.
[Claim 4]
The predetermined position is a position corresponding to at least one of the break-up position and the average particle size of the fuel spray at the break-up position and the average speed of the fuel spray at the break-up position.
The fuel injection valve according to claim 2.
[Claim 5]
The predetermined position is set closer to the intake valve as the average particle size of the fuel spray at the breakup position is larger, and the faster the average speed of the fuel spray at the breakup position is, the more the intake valve is used. Set to a close position,
The fuel injection valve according to claim 4.
[Claim 6]
The breakup position is a position where the average particle size of the fuel spray or the number of particles per unit volume becomes an extreme value.
The fuel injection valve according to claim 4.
[Claim 7]
The intake port branches into two at the branch downstream of the fuel injection valve.
The cross-sectional shape of the intake port is the cross-sectional shape closer to the intake valve than the branch portion.
The fuel injection valve according to claim 2.
[Claim 8]
The intake port is a straight port,
The cross-sectional shape of the intake port is the cross-sectional shape at the predetermined position.
The fuel injection valve according to claim 2.
[Claim 9]
It is set to include the inner wall of the intake port closer to the intake valve than the predetermined position in the virtual extension region extending the region within the spray angle range of the fuel spray.
The fuel injection valve according to claim 2.
[Claim 10]
Equipped with a atomization promotion mechanism for injecting atomized fuel,
The fuel injection valve according to claim 2.[Claim 11]
A port injection type internal combustion engine equipped with a fuel injection valve that injects fuel into the intake port of the internal combustion engine.
The breakup position of the fuel spray injected from the fuel injection valve is set upstream from the intake valve,
The cross-sectional shape of the intake port and the cross-sectional shape of the cross section perpendicular to the injection direction of the fuel spray at a predetermined position based on the breakup position have different width dimensions in each of the two axes orthogonal to each other. The longitudinal direction of the cross section of the intake port is set to match the longitudinal direction of the cross section of the fuel spray.
Port injection type internal combustion engine.
[Claim 12]
A port injection type internal combustion engine equipped with a fuel injection valve that injects fuel into the intake port of the internal combustion engine.
The breakup position of the fuel spray injected from the fuel injection valve is set upstream from the intake valve,
The cross-sectional shape of the fuel spray in the cross section perpendicular to the injection direction of the fuel spray at a predetermined position based on the break-up position is a shape obtained by reducing the cross-sectional shape of the intake port.
Port injection type internal combustion engine.
[Claim 13]
It is set to include the inner wall of the intake port closer to the intake valve than the predetermined position in the virtual extension region extending the region within the spray angle range of the fuel spray.
The port injection type internal combustion engine according to claim 11.