JPS5828512A - internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to an intake system for an internal combustion engine.

One way to improve fuel consumption is to use a lean mixture. However, with a lean mixture, the flame propagation speed is inherently slow, so it is difficult to obtain stable combustion due to the slow combustion rate. In some cases, the combustion rate becomes even slower, making it even more difficult to obtain stable combustion. It is conventionally known to generate a swirling flow within the combustion chamber as a method of increasing the combustion speed.
If this swirling flow is too strong, a large amount of heat escapes from the inner wall surface of the syringe, resulting in a decrease in thermal efficiency.On the other hand, if it is too weak, the combustion rate cannot be sufficiently increased, resulting in poor combustion.
Therefore, it is clear that there is an optimum swirl flow strength depending on the type of engine.

SUMMARY OF THE INVENTION An object of the present invention is to provide an intake system for an internal combustion engine that can generate a swirling flow of strength suitable for stably burning a lean mixture having an air-fuel ratio of 20 or more in a combustion chamber.

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

Referring to FIG. 1 and FIG. 2, 1 is a cylinder block, 2 is a cylinder dog port, and an f-stone that reciprocates within the cylinder 1;
3 To the cylinder fixed on the cylinder head 1, 4 to the piston 2 and cylinder, 3 to the combustion chamber formed between them, 5 to the intake valve, and the scratch formed in the cylinder head 3. Helical type intake J-), 7 indicates an exhaust valve, and 8 indicates an exhaust port formed in the cylinder head 3, respectively. Although not shown in the figure, an igniter is arranged within the combustion chamber 4.

From Figure 3 to Figure 5, the helical ima air in Figure 2--FS
Oy#This helical air intake diagram shows autumn 6
As shown in No. 41iK, the flow path axis 11m is composed of a slightly curved inlet passage part and nine spirals formed around the valve axis of the intake valve 5, and the inlet passage part m The spiral part IKm is connected in a linear manner.

sg, 4th IQ, and the upper side wall WO on the side closer to the spiral axis bK
Formed in an a-shaped slope facing downward, ζO slope i19
a As it approaches the midline spiral IIl, the entire side wall surface 9 faces downward so that it is received by the widening 711 at the connection between the inlet passage part M and the spiral part I, and the slope is 9 m.
is formed. Upper half public corporation intake valve guide 10 on side 11 surface 9
(Fig. 2) The peripheral wall of the cylindrical protrusion 11 formed on the upper wall surface of the intake 4-toe of the peripheral blade is connected smoothly between the peripheral walls of the blade-side wall surface 9.
The lower half of the spiral part B is the vortex at the terminal part C.
is connected to the side wall surface 12 of. In addition, the upper wall surface 1 of the spiral part B
3 is connected to the downward steeply inclined wall DK at the end C of the spiral.

On the other hand, as shown in FIGS. 1 to 5, to the cylinder,
A branch passage 14 of substantially uniform length is formed in the door 3, branching from the inlet passage part A, and this branch passage 14 is connected to the spiral terminal part C.
connected to. Entrance opening of branch road 14! 5 is formed on the side wall 1[9 near the inlet opening of the inlet passage section M, and the outlet opening 16 of the branch passage 14 is formed at the upper end of the side wall surface 12 at the spiral end C. Furthermore, an on-off valve insertion hole 17 is bored in the cylinder and in the door 3, and extends through the branch passage 14, and a rotary valve 18, which acts as a passage on-off valve, is inserted into each of the on-off valve insertion holes 17. be done. The rotary valve 18 is disposed within the branch passage 14 and includes a thin plate-shaped valve body 19 as shown in FIG. 9, and a valve stem 20 integrally formed with the valve body 19. l On-off valve insertion hole 17
It is rotatably supported by a guide sleeve 21 fitted therein. The valve stem 20 is centered upwardly from the guide sleeve ztol[il, and an arm 22 is fixed to the central protruding end of the valve stem 20. Referring to FIG. 24, and the surge tank 24 further communicates with the atmosphere via an air duct 25 and an air cleaner 26. Referring to the 211th row KIIIloE, each branch pipe 23 is equipped with a round fuel injection valve 27 that injects fuel into the intake port 6, and inside the air duct 25 is a slot valve connected to an accelerator pedal. ) Le valve 2B is inserted. On the other hand, the ends of the arms 220 of the rotary valves 18 of each cylinder are connected to each other by a connecting rod 29, and this connecting rod 29 is connected to the negative pressure mailer unit 30.
It is fixed to the main control rod 31 and connected to the large control rod 32. Negative pressure membrane equipment 30 companies〆ear 7 ram 31
It has a negative pressure chamber 33 isolated from the atmosphere by , and a diaphragm pressing compression spring 34 is inserted into the negative pressure 1i33. Negative pressure chamber 33 Fi is connected to a valve chamber 37 of an atmospheric ventilation control valve 36 via a conduit 35 . The valve chamber 37 is connected to the surge tank 24 on the one hand through a check valve 38 that allows flow only from the valve chamber 37 into the surge tank 24, and on the other hand is connected to the atmosphere through an atmosphere communication port 39 and an air filter 40. communicate. Further, the atmospheric delay control valve 36 is equipped with a solenoid valve 41, and this solenoid valve 41 is in communication with the atmosphere yj! -)3
9, a movable syringer 43 connected to the valve body 42, and a solenoid 44 for suction of the movable syringe. Solenoid 44 of solenoid valve 41
It is connected to the output terminal of the electronic control unit y) 50. j!
In addition, an I-tension and meter 45 are attached to the throttle valve 2B. This potentiometer 45 is the throttle valve 2
An output voltage proportional to the opening fK of the throttle valve 28 is generated in the slider 45& by a slider 45m connected to the throttle valve 8 and rotating together with the throttle valve 28, and a fixed resistance of 415%.

The electronically controlled enit 50 is a digital combination, an i-eclog four set (MP) that performs various arithmetic processing.
U) 51, Random Access Memory (RAM) 52, Control! A read-only memory (ROM) 53 in which programs, calculation constants, etc. are stored in advance, an input/-) 54, and an output port 55 are connected to each other via a bidirectional path s6!
! It is continued. Further, within the electronic control device unit 50, there is provided a light generator 57 for generating various black and white signals.

A negative pressure sensor 58 for detecting negative pressure in the surge tank 24 is connected to the input/-) 54 via a mu D converter 59, and a potentiometer 4 is connected to the input/-) 54.
5 is connected via a mu-D converter 60. Further, a rotation speed sensor 61 is connected to the input data R54. The negative pressure sensor 5sFi generates an output voltage proportional to the negative pressure in the surge tanctor 24, and this voltage is converted into a corresponding binary number in the mu D converter 60, and this binary number is passed through the input 1-) 54 and the path 56. and is input to the MPU 51. II
I! As mentioned above, the tension meter 45 generates an output voltage proportional to the opening and closing of the throttle valve 28, and this voltage is converted into a corresponding binary number by the D converter 60, and this binary number is inputted. and M via path 56
It is input to PU 51. On the other hand, the rotation speed sensor 61 generates a negative pass every time the engine crankshaft rotates by a predetermined crank angle WIL, and this I-cruise is input to the MPU 51 via the input port 54 and the pass 56.

Output/-) 55 is provided to output data for operating the fuel injection valve 27 and the solenoid valve 41. -Binary data is written from the MPU 51 to the port 55 via a path 56.The output terminal of the output/-) 55 is connected to the solenoid 44 of the electromagnetic valve 41 via the power amplifier circuit 62 on the one hand; On the other hand, down counter 6
3 to the corresponding input terminals. This down counter 63 is provided to convert the binary data written from the MPU 51 into the corresponding time length, and this down counter 63 is provided to convert the binary data written from the MPU 51 into the corresponding time length. The generator 5 counts down the data.
It starts with the clock signal of 7, and when the count value reaches 0, the counting is completed and a count completion signal is generated at the output terminal. 8-R free.

f70. The reset input terminal wing of f.4 is connected to the output terminal of the down counter 63, and the reset input terminal wing of f.
The 40 set input terminal 8 is connected to a black and red generator 57. This trifle, Pu7I2. f64 is set at the same time as the start of countdown by the clock signal of the evening generator 57, and when the downcount is completed, the /run counter 6 is set.
It is reset by the count completion signal of 3. Therefore, 8-R7, differential 0. The output terminal q of f64 is at a high level while the down count is being performed. The output terminal Q of the s-i flip flop O, f@4 is connected to the fuel injection valve 27 via the power amplification circuit 65, and therefore the fuel injection valve 27 is energized by the down counter 63 counting down. I know it will happen.

On the other hand, as described above, the output terminal of the output port 55 is connected to the solenoid valve 41. Solenoid Y44- of solenoid valve 41!
When fi is energized, the valve body 42 opens the atmosphere communication /-) 39. As a result, the inside of the negative pressure chamber 33 becomes atmospheric pressure, so the Meir 72m 31 is moved downward by the spring force of the compression spring 34, and the rotary valve 18 is thus rotated to fully open the branch passage 14. do. On the other hand, when the solenoid 44 of the electromagnetic valve 41 is deenergized, the valve body 42 closes the atmospheric communication /-) 39. When the negative pressure in the check valve 38 and the intake manifold 23 becomes larger than the negative pressure in the negative pressure chamber 33 of the negative pressure membrane device 30, the valve opens, and the negative pressure in the intake manifold 2s increases to the negative pressure chamber. When the negative pressure in the negative pressure chamber 33 also decreases, the valve closes, so as long as the valve body 42 is closed, the negative pressure in the negative pressure chamber 33 is suction! The maximum negative pressure generated within the Nifold 25 is maintained for a while. When negative pressure is applied inside the negative pressure chamber 33, the diaphragm 31 releases the compression spring 3.
As a result, the rotary valve 18 is rotated and the branch passage 14 is closed.

FIG. 11 shows the negative pressure P(-1&) in the surge tank 24 and the air-fuel ratio to the engine rotation of 11 kN (rpm) K. In Fig. 11, the numerical values written in the figure indicate the air-fuel ratio, but in reality, Fig. 11 is written on Kle in the figure, and the fuel injection time that results in a large air-fuel ratio is written!
, f. Therefore, when the engine speed N and the negative pressure are set at a constant level, the fuel injection time is determined from Figure 11, and the air-fuel ratio dll11, which is supplied to the cylinders of the own machine, is ktk as shown in Figure 9. 2. The fuel injection time fFi shown in No. 1111 is stored in the ROM 5S in advance. As you can see from the 11th WA, the fuel injection amount is between the engine speed N or about 14001% to fiff3200rpm, and the negative pressure is filling #3! ! Osm-The air-fuel ratio is set to 2 when the engine is in full operation. Furthermore, when the engine speed (Pl) is between 600 rpm and approximately 1,400 rpm, the air-fuel ratio decreases to 1 as the rotation speed N decreases.
It is set to decrease in increments of 12 to 2.75. If the air-fuel ratio is large when the engine rotation speed N becomes small, torque fluctuations occur, and in order to suppress this torque fluctuation, the air-fuel ratio is made smaller as the engine speed decreases. On the other hand, when the negative pressure P is 1350 swzHg and it is very hot, the air-fuel ratio increases to 100■Hg as the negative pressure P increases! ! kj) is set to decrease by 1 to 2. This will cause torque fluctuations if the air-fuel ratio becomes very hot when the negative pressure P increases.
In order to suppress this torque fluctuation, the air-fuel ratio is made smaller as the negative pressure P becomes larger. Also, the engine speed N!)! 'At 3200rpm and above, the air-fuel ratio is 1
00 rpm is set to decrease in increments of 0.5 to 1.5, thereby making it possible to obtain a straw output when the engine speed N is high.

The control of the fuel injection amount by "Yy" in FIG. 11 is performed when the opening degree of the throttle valve 28 is smaller than 4 in FIG. 12; When the amount is large, the fuel injection amount is controlled by the opening degree of the throttle valve 280.

In FIG. 12, the vertical axis 4 indicates the opening degree of the throttle valve 2B, and indicates the throttle opening degree so@a in a fully open state. As shown in Fig. 12, when the engine speed N is 100 orpm, it is 30' to 40, and when the engine speed N is 4000 rpr*, @SO
〜6 枦. The negative pressure P corresponding to this opening lL# is the first
Indicated by a dashed line T in 1E. Therefore, Figure 11 O-break
Also, when the negative pressure P is small, that is, when the opening degree of the throttle valve 28 is larger than the opening degree 4 of the 12th rIAO, the fuel injection amount is controlled according to the throttle valve 280 at once. The broken line in Figure O] also shows that when the negative pressure P is small, the air-fuel ratio is suddenly reduced by 1 kK as the negative pressure D decreases in order to obtain high output. Since the air-fuel ratio changes greatly, if the air-fuel ratio is carbonized in accordance with the negative pressure, fine control becomes difficult. Thus, when the negative pressure P is small as shown by the broken line in FIG. 111, the fuel injection amount is controlled by the opening degree of the throttle valve 28. In addition, in No. 1211, the relationship between the engine speed
53.

FIG. 13 shows the air-fuel ratio to l1f1 of the throttle valve 28 and the engine rotational speed NK. In FIG. 13, the good value written in the figure indicates the air-fuel ratio, but in reality, FIG.

It has become zo. Therefore, when the engine speed N and the throttle valve opening are determined, the fuel injection time becomes constant as shown in Figure 13, and the air-fuel ratio supplied to the engine cylinder at that time becomes the numerical value shown in Figure 13. . The fuel injection times m and 'f shown in FIG. 13 are stored in the ROM 53 in advance. As can be seen from FIG. 13, the fuel injection amount is set so that the air-fuel ratio decreases as the throttle valve opening θ increases, and when the throttle valve 28 is fully opened, the air-fuel ratio is approximately 12.5. .

Next, fuel injection control will be explained with reference to FIG. Referring to FIG. 15, first, in step O, the output signal of the rotation speed sensor 61 is input to the MPU 51, and the engine rotation speed N is calculated. Next is Stella 7”
At 71, the output signal of the tension meter 45 representing the throttle valve opening is inputted to the field υ51, and then the output signal of the negative pressure sensor 58 that generates a negative pressure P at the stage 2 is inputted to the MPo51K. 0 then step, 7
In step 3, it is determined whether the point Q (N) of the 12th E, which is determined by the torque opening degree - and the engine speed N and K, is larger than the opening degree 4 in the iris diagram 12. Ste, e in f73
When it is determined that (N) is not large enough to open J[ao, the fuel injection time is calculated from Mazda by proceeding to f74 and showing the 11th wJK.
On the other hand, the opening degree of step 73 is 0o.
When it is determined that the height is also large, proceed to step f76 and the fuel injection time 〒 is calculated from M and f shown in Figure 13.
Next, proceed to step f75. In step step 75, step f
The drive data corresponding to the fuel injection time te determined in step 74 or step 9f'16 is written to the output 4-55, and fuel is injected from the fuel injection valve 27 for this fuel injection time 〒. Therefore, an air-fuel mixture having an air-fuel ratio as shown in FIG. 11 or 13 is supplied into the engine cylinder.

FIG. 14 shows the engine speed N (r
pm ) and negative pressure p(-smI[g
), this related mineral pre-ROM 53
stored within. The solenoid valve 41 is indicated by the solid line W in Figure 1814.
It is energized in the region shown by the hatching above the Actual 1IilW in FIG. 14 shows a state where the amount of intake air is almost constant. Therefore, when the amount of intake air exceeds a predetermined amount, the data to energize the solenoid 44 is output - part 5.
5 and the solenoid 44 is energized. When the solenoid l'44 is energized, the rotary valve 18 fully opens the branch passage 14.

Therefore, it can be seen that when the intake air amount is large, the rotary valve 18 fully opens the branch passage 14, whereas when the intake air quantity is small, the rotary valve 18 closes the branch passage 14.

As mentioned above, when the engine is operating at low speed and low load with a small intake air volume, the rotary valve 18 closes off the branch passage 14.

At this time, the intake air sent into the inlet passage A swirls along the upper wall surface 13 of the spiral part BO, descends inside the spiral part B, and then flows into the combustion chamber 4 while swirling, resulting in combustion. A strong swirling flow is generated within the chamber 4. Figure 16 shows the relationship between the swirl ratio g (the number of turns of the swirling flow in the combustion chamber at a crank angle of 360 degrees) and the fuel consumption rate Q.As can be seen from Figure 16, the air-fuel ratio is When using a very lean mixture, the fuel consumption rate q is low when the swirl ratio is in the range of approximately 1.5 to 3, and the swirl ratio is 8 or higher.
The fuel consumption rate worsens no matter how large or small the helical m intake according to the present invention is from 1.5 to 3.
Swirl ratios in the range of can be obtained, and thus stable combustion can be obtained even with ultra-lean mixtures.

On the other hand, during engine high-speed, high-load operation with a large amount of intake air, p-
Since the tariq 18 opens, a part of the intake air sent into the inlet passage part M is sent into the spiral part B via the branch passage 14 with low flow resistance and is then sent from the stone 0 branch passage 14. The intake air that has flowed into the swirl portion B flows from the inlet passage portion A into the swirl portion B and has the effect of decelerating the intake air flow flowing while swirling, so that the swirl flow is weakened. In this way, when the engine is operated at high speed and under high load, the rotary valve 18 opens, which does not increase the overall flow path area, but instead weakens the swirling flow, ensuring high filling efficiency and thus achieving high output. Obtainable. In addition, an inclined side wall portion 9a is provided at the entrance passage portion.
By providing this, a part of the intake air that is sent into the inlet passage is given a downward force, and as a result, this intake air swirls along the lower wall surface of the inlet passage. Since it flows into part B, the flow resistance is small.
In this way, the filling efficiency during high-speed, high-load operation can be further improved.

As described above, according to the present invention, an optimal swirl flow with a swirl ratio of 1.5 to 3 is generated in the combustion chamber, so that stable combustion can be achieved even when using a super-lean mixture with an air-fuel ratio of about 22. Obtainable. Furthermore, when the engine speed is low and when the negative pressure in the intake passage is large, the air-fuel ratio of K is reduced, so torque fluctuations can be suppressed and good drivability can be ensured. Further, when the engine is operated at high speed and under high load, the air-fuel ratio is reduced, so high output can be obtained, and the rotary valve opens, which increases the charging efficiency, so that the engine output can be further increased.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an internal combustion engine according to the present invention, and FIG.
3 is a perspective view showing the shape of a helical air intake, 4th m is a plan view of 3@(1), and 5th is a sectional view taken along line 1-1 in the figure. Figure 6 is a cross-sectional view taken along the branch road, taken along line Vl-11111 in Figure 4, Figure 7 is a cross-sectional view taken along line ■-■ in Figure 4. Figure 8 is a nine-section map taken along the lines ■-■- in Figure 4, and Figure 9.
The figure is a perspective view of the rotary valve O, Figure 10 is an overall view of the intake system, Figure 11 is a diagram showing the air-fuel ratio determined by the negative pressure in the surge tank and the engine speed, and Figure 12 is a diagram showing the throttle valve opening control. Diagram showing the opening degree of the switching valve, 1st $1i
is a diagram showing the air-fuel ratio determined by the throttle valve opening and the engine speed, No. 145! l is a diagram showing the opening area of the on-off valve O,
Figure 15 - Chart 7--Chart showing the operation of fuel injection control;
FIG. 16 is a graph showing the relationship between fuel consumption rate, swirl ratio, and O. 6-helical intake 4-t, 24-・surge tank, 2
7-Fuel injection valve, 28... Throttle valve, 58...
- Negative pressure sensor, 61-... rotation speed sensor. Patent applicant Tome Yu Jidosha Kogyo Co., Ltd. Patent attorney Akira Aoki Patent attorney Nishi; Kazuyuki Tate Patent attorney ★ 1) Tadashi Patent attorney Akira Yamaguchi 1st η1 4th 5th 60th 7th 81st! l 9th 120 N (r, p, m) 13th yJ 14th 15th T: fJ -1111” 16th 1 2 5 s

Claims (1)

[Claims] 41g1 In response to engine speed and negative pressure in the intake passage, the engine speed is approximately 1400 rpm or more and the negative pressure in the intake passage 'l)'a#'! 1'-50m11g or bFtj'!
When I'-350mug, a lean mixture with a constant air-fuel ratio is formed, and when the engine speed is approximately 140 rpm or less, as the engine speed decreases, the air-fuel ratio of the mixture is reduced and the intake passage is Equipped with a fuel supply device designed to reduce the air-fuel ratio of the air-fuel mixture as the internal pressure of the KFi intake passage decreases when the internal negative pressure is as low as -50 mHg, and the intake air (/-) is helical type. Formed internal combustion engine intake system.