JPH01320A - engine intake system - 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 (Field of Industrial Application) The present invention relates to an intake system for an engine, and more particularly to an intake system for an engine that generates a swirl of intake air within a cylinder.

(Prior art) In recent engines, there are multiple
In particular, many models have two open intake ports.

On the other hand, it is well known that in order to ensure combustion stability, particularly combustion stability at low loads, it is effective to generate intake air swirl within the cylinder. Because of this swirl generation, the engine's intake passage has become blown away. For example, in an engine with two intake ports for one cylinder, an on-off valve is provided for the independent intake passage connected to one intake port, while a swirl is provided in the other intake port within the cylinder. so that it is oriented substantially tangentially to the cylinder. In this device, a strong swirl is ensured by keeping the on-off valve closed during low load and supplying intake air only through the other intake port. In other words, the swirl generation due to the intake air supplied from the other intake ports is 1
- This prevents the intake air from being blocked by the intake air supplied from the above intake ports. 5. Of course, at high loads, by opening the on-off valves mentioned above, sufficient intake air is supplied through both intake ports. This allows the output to be secured.

[-As mentioned above, in a device that is equipped with an on-off valve to generate swirl, not only this on-off valve but also an actuator etc. to open and close the on-off valve are required separately. The structure becomes more complicated and the cost increases.

From this point of view, there is a device as shown in Japanese Patent Application Laid-Open No. 156408/1983 that can generate swirl with a configuration as small as possible in the cylinder. In the case described in this publication, two intake ports are opened in one cylinder, and the open area of the -1y intake port is made larger, and the open area of the other intake port is made smaller. As for the orientation direction of both intake ports with respect to the cylinder, for example, the intake port on one side is oriented so as to generate a clockwise swirl in the cylinder, and the other intake port is oriented in a counterclockwise direction. 1, oriented to generate swirl;
In this way, the direction of swirl generation for both intake ports is correct! 1
:The relationship is reversed, or J. Sometimes, in the cylinder, if the effect opens [
Swirl in the direction set by one intake port with a large area is generated (swirl generation in the clockwise direction).

(Problem to be Solved by the Invention) However, in 2-), where the automatic opening area of the intake port is set to be different in size, the effective amount [1 area of the intake port as a whole] must be made sufficiently large. becomes impossible, and this makes a significant drop in output unavoidable. In particular, when the load is high, the intake resistance of the other intake port, which has a small effective opening area, becomes extremely large, making it difficult to secure sufficient intake air M (secure output). In addition to this, the intake air supplied from the intake port with the larger effective amount 11 area has a lower flow velocity (which ultimately generates a strong swirl in the cylinder), making it undesirable.More details To explain, the momentum of a swirl can be thought of as kinetic energy, so both the flow rate and the flow velocity are related.1.The flow velocity decreases at low load, where the flow rate is originally small.1.A strong swirl is generated. The limit will be reached at L.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an intake system for an engine that can effectively generate swirl while suppressing a decrease in output with an extremely simple configuration.

(Step-by-Step Action for Solving Problems) To achieve the above-mentioned objects, the present invention has the following configuration. That is, a first intake port that draws intake air into the cylinder 1-) in a direction that generates swirl;
A second intake port for sucking intake air in a direction that inhibits swirl generation by the first intake port is opened.

the intake passage for the one cylinder is a common intake passage;
The common intake passage includes a first branch passage branched from the downstream side of the common intake passage and connected to the first intake port, and a second branch passage connected to the second intake port.

A deflection wall is formed on the inner wall of the intake passage to deflect intake air from the common intake passage toward the first intake port.

With this configuration, even if the effective opening areas of the first and second intake ports are the same size,
Particularly when the load is low, the force of the swirl caused by the intake air supplied from the first intake port becomes stronger than the force of the swirl caused by the intake air supplied from the second intake port. This generates a swirl that follows the flow direction of the intake air supplied from the first intake port. In addition, the increase in intake resistance (lower flow M coefficient) due to the provision of deflection walls is due to the second
is smaller than the increase in intake resistance when reducing the amount of movement [1 area] of the intake port itself.

This prevents a significant decrease in the output.7 (Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the attached drawings.

1 to 3 show a first embodiment of the present invention. In these FIGS. 1 and 2, I is the engine body, and the engine body! teeth.

Cylinder block 2. Cylinder head 3 and cylinder]/
It consists of a head force bar (not shown), etc. A piston (5) is installed inside the engine body (1), and a combustion chamber (7) is formed on the one side of the piston (6).In other words, the cylinder block (2) and one end of the cylinder (5) Combustion 7
is defined. , H The combustion chamber 7 has the tth! 3 and the second two intake ports 8, 9 and two exhaust ports 1
0 and 9 are open, and the first and second intake ports 8.9
The opening L1 diameters of the two are the same. [・, Intake port 8
9 are each equipped with an intake valve 11 (the intake valve on the first intake port side is not shown), and the exhaust port 1 () is equipped with an exhaust valve 12 (only one is shown). The valves are operated by a valve mechanism (not shown) to open and close each port 8, 9, and 10 at predetermined timings. The combustion chamber 7 is also equipped with a spark plug 13. .

1., intake port 8.9. The arrangement of the exhaust port 10 and the spark plug 13 will be described in more detail as follows. First, as shown in FIG. 3, let the cylinder axis be 0, and let 2 be a virtual line extending in the cylinder arrangement direction (engine output axis direction) within i' + ri orthogonal to the cylinder axis 0. The two intake ports 8.9 are connected to the combustion chamber 7.
Of these, in the half area divided by the imaginary line, they are located adjacent to each other in the direction of the imaginary line β. Further, the two exhaust ports 10 are located adjacent to each other in the direction of the imaginary line C in the remaining half region of the combustion chamber 7 divided by the imaginary line C. Furthermore, in the embodiment, the camshaft (not shown) for driving the intake and exhaust valves is one
The camshaft passes through the cylinder axis O and extends parallel to the imaginary line β. and 1 spark plug
3, the large part of which is located at the cylinder axis 0 (the center of the combustion chamber 7), and is arranged at an angle with respect to the cylinder axis O to avoid interference with the camshaft. ing.

Intake pipes 14 are connected to the cylinder intake pipe 3 for each cylinder. Outside air is introduced into the intake pipe 14 through a surge tank, an air cleaner, an air flow meter, a throttle valve, etc. (all not shown). A common intake passage 15 extends between the intake pipe 14 and a predetermined area inside the cylinder head 3. The downstream end side of the common intake passage 15 in the cylinder radiator 3 is connected to a first
It is defined by a branch intake passage 16 and a second branch intake passage 17. The first branch intake passage 16 communicates with the first intake port 8, and the second branch intake passage 17 communicates with the second intake port 9. Therefore, the first
The intake air taken in from the second intake ports 8 and 9 is configured to rapidly swirl in the opposite direction within the cylinder 5. More specifically, the intake air supplied from the first intake port 8 flows clockwise within the cylinder 5, as shown by the arrow in FIG. On the contrary, the intake air supplied from the second intake port 9 flows counterclockwise in FIG. 3 within the air IIS. In addition, 1- common intake passage +5
and the first and second branch intake passages 16°17 form the intake passage 1.
8.

A deflection wall 19 is provided in the intake passage 18 .

The deflection wall 19 is formed within the cylinder head 3 (molded integrally with the cylinder head 3) and is located directly in the direction of the partition wall X. Such a deflection wall 19 substantially constitutes an inner wall (side wall) of the intake passage 18 in a certain range extending from the common intake passage 15 to the second branch intake passage 16. This deflection wall 19 is formed on a side wall of the common intake passage 15 on the side opposite to the first intake port 8 in the direction of the imaginary line. And the deflection wall 19 is
The partition wall X protrudes toward the branch portion 2o serving as a flow rate, and its protruding end is indicated by reference numeral 19a. Such a deflection wall 19 narrows the distance between the branch section 20 and the deflection wall 19 by its protruding end 19a. As shown in Figure 6, the intake passage area (effective opening surface M) of this throttle part
Sl is smaller than the intake passage area S4 of the corresponding first branch intake passage 16. However, the intake air passage area S of the L2 throttle portion is approximately the same size as the intake air passage area S2 of the second branch intake passage 17. Moreover,
The upstream side wall surface 19b of the deflection wall 19 is curved so as to approach the axis of the common intake passage 15 as it goes from the common intake passage 15 toward the combustion chamber 7, and the upstream side wall surface 19b is curved along the extension line of the curve of the upstream side wall surface 19b. The branch part 20 is located (
(See dashed lines in Figures 1 and 3). Due to both the throttling action and the deflection action by the deflection wall 19, the intake air from the common intake passage 15 is diverted to the first branch intake passage! It is set to tend to flow more than 6.

1. One fuel injection valve 21 is installed in the common intake passage upstream of the deflection wall 19. Q# of fuel is supplied from the fuel injection valve 21 through the common intake passage 15 into the first and second branch intake passages 16,17. 7 However, the fuel from the fuel injection valve 21 is designed not to hit the deflection wall 19.

Therefore, according to the above-mentioned intake device, intake air is drawn into the combustion chamber 7 by lowering the piston 6, but the intake resistance in the second branch intake passage 17 is increased by the deflection wall 19, and Ti side wall surface 1 of deflection wall 19
9b actively deflects the intake air into the first branch intake passage +6.

As a result, the intake air -1 to the first branch intake passage 16 is
The amount of air taken into the second branch intake passage 17 is significantly larger, and the intake air from the first intake port 8 can generate a strong swirl in the combustion chamber 7, improving combustibility. Can be done. In this case, in the above-mentioned intake device, the second
Compared to the case where the opening area of the intake hole 9 is made smaller by 4°, the flow coefficient can be prevented from being significantly lowered. For this reason, the decrease in intake air volume, especially when loaded with high brass, is suppressed as much as possible.
It is possible to improve the combustibility while minimizing the reduction in output.Therefore, in the intake system of the present invention, both intake ports are used to generate swirl. There is no need to intentionally make the opening diameters of 8 and 9 different, and from the perspective of securing output, the degree of freedom in setting HL remains.
(Fig. 4 shows a second embodiment of the present invention, and Fig. 5 shows a third embodiment of the present invention. In each of these embodiments, the same components as in the previous embodiment are the same. Reference numerals are given and explanations thereof are omitted.

The second embodiment shown in FIG. 4 shows an S port type in which the number of intake ports is three in total. In this embodiment, there is one first intake port 8 and two second intake ports 8.
Intake ports 9a and 9b are provided. These 3
The two intake ports 8.9a, 9b are arranged in the circumferential direction of the combustion chamber 7. Branch passage in intake port 8! 6 are connected, a branch passage 17a is connected to the intake port 9 Fl, and a branch passage 17b is connected to the middle intake port 9b.

1- Branch passages 16 and 17b are partitioned by a partition wall Xi, and 17b and 17a are partitioned by a partition wall X2.

As in the previous embodiment, the upstream wall surface 19b of the deflection wall 19 has an extension line extending from the branching portion 20 (11th flow end of the partition wall X1).
(See the broken line in Figure 4).

In this embodiment, as in the previous embodiment, the intake air from the common intake passage 15 is actively deflected to the first branch passage 16. As a result, the overall intake air amount can be secured to F-minutes, and the intake air M of the first intake port 8 can be made larger than the intake air amount of the second intake ports 9a, 9b (particularly 9b). Similar to the first embodiment, a strong swirl can be generated.

The third embodiment shown in FIG. 5 shows a four-port type with a total of four intake ports. Note that the exhaust ports are not shown, but the number is the same as that of the intake ports, etc.
The number can be set as appropriate. In this example,
Two first intake ports 8a, 8b and two second intake ports 9E1.9b are provided. These four intake ports 8a, 8b, 9a, 9b are the first intake ports 8a, 8b from the left side, as shown in FIG.

The second intake ports 9h and 9a are arranged in a line on one side of the combustion chamber 7 in that order. A first branch passage 16a is connected to the intake port 8a, a branch passage 161) is connected to 8b, a branch passage +7b is connected to 9b, and a branch passage 17a is connected to 9a.

Ten branch passages + 6 a and 16b are connected to 1 by partition x3
It is drawn! 6b and 171) are separated by a partition wall X4, and 17b and 17a are partitioned by a partition wall x5. Then, the branch part 20'(
The extension line of the upstream side wall surface 19b passes through the 1-1 flow end of the partition wall XI (see the broken line in Fig. 5).
. As a result, the intake air is
b, it is mainly deflected actively toward the first branch passage 16a, and the swirl can be strengthened by increasing the radius of swirl compared to the first and second embodiments of Section 1111. . At this time, the intake air guided to the first intake port 8b via the first branch passage 16t also flows in the swirl generation direction in the combustion chamber 7, 8. J.
An extremely large swirl will be generated by the intake air taken in from 8b.

Next, a test example in which the present invention was applied to an in-line four-cylinder engine If;

First, a test example to which the present invention was applied will be explained.
There are two types of this test example. The first test example is S
OII C(5INGLE 0VERIIEAD CA
MSII 8F゛[) to naturally aspirated (NATURAL,
ASl'1RATION). The spark plug 13 is positioned obliquely with respect to the cylinder axis O, as shown in FIG. The second test example is D
OII C (0011111, E 0VERIIEA
D CAMSHAFT) The exhaust turbocharger performs supercharging. And spark plug 13
is 1 +' without being tilted with respect to the cylinder axis 0
J The cylinder is arranged extending in the same direction as the cylinder axis 0. In both of the test examples 1 and 2 described above, the r method for each part shown in FIG. 6 is as follows.

S port: The common intake passage 15 has an area of 1 area and a circular cross section Ki, and its 0 diameter corresponds to a diameter of 37 mm when made circular.Therefore, Sa=IO75 mm2.

S exposure The ff effective amount of 1 area between the protruding end 19;l of the knee white wall 19 and the branch portion 20 is set to be approximately the same size as S2, which will be described later.

S2: The effective amount of the second branch passage 17 is 1 area (the effective amount of both intake ports 8 and 9 is 11 areas), the cross section is circular, and the diameter is 30 mm. So, S2 = 707
mm'.

S is the projected area of the knee white wall 19 when viewed from the rear side of the common intake passage 15, and is 16% of the size of S6 in 1 U.

The length of the flow side wall surface 19b is 24 mm.

Q2: Distance from the protruding end 19a of the deflection wall 19 to the branch portion 20, which is 21 mm.

Qx: At the position of the branching part 20, 1 with respect to the straight line a connecting the protruding end 19a and the branching part 20, the flow side wall + fii
19 Offset of directivity line β of b -tl: Yes, ρ.

= +: 3 mm (the direction closer to the intake port 9 from the branch portion 20 is considered to be an offset in the "+" direction).

Note that the distance between the protruding end 19a and the intake valve (intake port 9) is 20 mm in length along the axis of the branch passage 17.

FIG. 7 shows Comparative Example 1. This comparative example 1 is
This corresponds to the above-mentioned Japanese Patent Application Publication No. 56-156408. And, for the test example 1 mentioned above,
- The only difference is that there is no white wall 19, and the area of movement [] of both intake ports 8 and 9 (branch passage 16 and eye 7) is different. The effective opening area of the intake port 8 is 683 mm2 (diameter 29.5 mm), and the effective opening area of the intake port 9 is 455 mm' (diameter 24°0 mm).

FIG. 8 shows Comparative Example 2. This comparative example 2 is
This test differs from Test Example 2 only in that the deflection wall 19 is provided in the intake pipe 14 (in the immediate vicinity of the cylinder head 3).

FIG. 9 shows a comparison of swirl strength between Test Example I and Comparative Example 1. In FIG. 9, the horizontal axis shows the lift of the intake valve: jt (valve open), and the vertical axis shows the rotation speed of the paddle wheel.

As is known, the paddle wheel is disposed within the cylinder 5, and the stronger the momentum of the swirl within the cylinder 5, the higher the number of revolutions thereof. As is clear from FIG. 9, it is understood that the swirl force of the test example to which the present invention is applied is stronger than that of comparative example 1.

The engine shown as r5TANDARDJ in FIG. 9 is an engine with the deflection wall 19 removed from the engine in FIG. (This also applies to the cases of FIGS. 10 and 11 below).

FIG. 1O shows r:, C5I? when the engine is actually operated for Test Example 1 and Comparative Example 1. It shows the relationship between the rate and five angular velocity fluctuations. The engine operating conditions are 1500 rpm, V/equal effective pressure 3 kg/
In steady operation at cm', the ignition timing is MI'3'1'' (optimum ignition timing). The angular velocity fluctuation rate is 0;
3 r 21 (1/ >; (: <: is considered to be an acceptable level;
CG when i / st = c, lr + l',
GR limit. Therefore, if E a 1 <f', Gl (if the rate is increased, Test Example 1
is about 396 more than Comparative Example 1.
'? rate can be increased. As this 1-Gl can be increased, the bombing loss can be reduced,
This results in 4 tons of fuel efficiency.

In the case of Test Example 1, the maximum output was approximately 2% lower than that of the r5TANDARIIJ engine, but such a low output does not cause any problems.

Fig. 1t shows EGR for Test Example 2 and Comparative Example 2.
(corresponding to FIG. 10). Engine operating conditions are +50 Or p m
, "1't'-1N dynamic pressure 3kg/cm'.

This is steady operation with an air-fuel ratio of 16. The ignition timing was set as close as possible to the optimum ignition timing within a range where no knocking occurred. As is clear from Fig. 11, even in the case of the exhaust turbocharged I)OHC engine,
It is understood that the EGR rate can be increased. In the case of this test example 2, the maximum output was increased by about 4% compared to the engine of [S1°AN D A RD J]. In other words, in the case of a supercharged engine, it is generally difficult to set the optimum ignition timing due to the problem of knocking, especially in operating conditions where maximum output is generated, and the ignition timing has to be significantly retarded from the optimum ignition timing. You won't get it. However, in Test Example 2, swirl was generated even in the operating state where the maximum output was generated, and the knocking limit was in the direction of 1. , it is thought that the maximum output has increased.

Furthermore, because the combustion rate was improved by the strong swirl, it can be shown that the exhaust gas salt temperature was lowered by about 40'C due to rapid combustion. As a result, the reliability of the supercharger was ensured, and the air-fuel ratio could be set to the BES L set (lean side), resulting in improved fuel efficiency and output.

Here, the preferable range of dimensional settings for each of the above-mentioned parts will be considered.

(1) First, from the viewpoint of ensuring sufficient intake air -■ especially under high load, it is not preferable to make S+ too small. That is, it is preferable not to substantially limit the area of the effective amount 11 of the branch passage +7 (intake port 9). Therefore, it is preferable that S≧82.

(2) From the viewpoint of ensuring a sufficient amount of intake air especially at high loads, it is not preferable to make S3 too large. In other words, increasing Si limits the (■motion amount [I area.-)j, S of the common intake passage 15.
: If + is too small, the effect of deflecting the intake air to the first intake port 8 will be weakened, which is not preferable. From this point of view, O,lS.

≦Si≦0.2S (preferably, the range is 1).

■If I2s is pushed too far toward the 1°+'' side (by moving it much closer to the intake port 9 side than the branch part 20), there is a strong tendency for the intake air deflected by the deflection wall 19 to be obstructed by the bulkhead X. I don't like it.

On the other hand, if 43 is pushed too far toward the "-" side, the intake air deflected by the deflection wall 19 will not flow smoothly toward the intake port 8. -Noj,
Even if the magnitude of n* is the same, the longer the length of f21, the stronger the deflection effect by the deflection wall 19.

Considering the points mentioned above, the absolute value of ε is 0.2.
1. It is best to set it so that

■The fact that the flood 1 is larger for the same height of the protruding end 1921 (which can be considered as the same size of Sz) means that the direction of the first flow side wall surface 19b (flood 1) or the relative to "
+” side, which is undesirable (
(See explanation in ■ above). On the other hand, there is a limit to increasing the height of the protruding end l 9 a due to the reduction in the amount of movement of the common intake passage 15. therefore,
R+ is preferably set in the range of 10mm5Q, ≦:S Om m. Note that eI is the common intake passage 1
5.1 Dynamic amount [1 It is possible to increase the larger the product, but in reality, the exhaust per cylinder of the engine that is weighted: i, :: (Mostly in the range of 400 to 600 cc. ), it can be covered by 1 minute within the range of 1 method mentioned above.

■The relationship between β1 and e2 is nine! This is related to the settings of AI itself and β2 itself, and also affects the settings of S3. From this point of view, it is preferable to set the range as 0.7j21≦e2≦1.311.

Incidentally, the above-mentioned items (1) to (2) can be similarly applied to the embodiment shown in FIG. 4 or FIG. 5.

Although the embodiment has been described below, the deflection wall 19 may be provided on the branch portion 20, 20' side. In addition, if intake air clearing is ensured to a certain extent, the opening diameters of the intake ports 8 and 9 can be made different (in this case, the effective volume [1 volume] of the first intake port 8 is increased). .

(Effects of the Invention) As is clear from what has been described below, the present invention can effectively create a swirl without sacrificing much of the output, and 1. improve combustion stability. .

Of course, in the present invention, since it is only necessary to provide a deflecting wall in the intake passage, the structure is extremely simple and can be implemented easily and at low cost.

[Brief explanation of the drawing]

FIG. 1 shows one embodiment of the present invention, and is a simplified blood diagram seen from the combustion chamber side. FIG. 2 is a sectional view taken along the line 11-11 in FIG. FIG. 3 is an enlarged explanatory diagram of FIG. 1. FIG. 4 is a simplified plan view showing a second embodiment of the present invention. FIG. 5 is a simplified top view showing a third embodiment of the present invention. FIG. 6 is a simplified top view showing the r-method settings for each part of the intake system of a test engine to which the present invention is applied. 7 and 8 are simplified side views showing the structure of a comparative example used for comparison with the present invention. FIG. 9 and FIG. 1O are graphs showing data obtained in Test Example 1 of the present invention and Comparative Example 1 shown in FIG. FIG. 11 is a graph showing data obtained in Test Example 2 of the present invention and Comparative Example 2 shown in FIG. 1: Engine body 2: Cylinder block 3 = Cylinder head 5: Cylinder 6: Piston 7: Combustion chamber 8: First intake port 9: Second intake port 11: Intake valve 14: Intake pipe 15: Common intake passage 16: First branch passage 17: Second branch passage 18: 18 Intake passage 19: Deflection wall 20: Branch part X: Partition wall Figure 1 Figure 4 Figure 5 A Figure 8 Figure 7 iθ Figure Eq Shakute (%) Figure 11 Shakute (%)

Claims (1)

[Claims] (1) For one cylinder, a first intake port that sucks intake air in a direction that generates swirl, and a second intake port that sucks intake air in a direction that inhibits swirl generation by the first intake port. are opened, and the intake passage for the one cylinder is a common intake passage;
a first branch passage branching from the downstream side of the common intake passage and connected to the first intake port; and a second branch passage connected to the second intake port; An intake system for an engine, characterized in that a deflection wall is formed to deflect intake air from a common intake passage toward the first intake port.