JPH0291418A - Suction system for engine - Google Patents

Abstract

PURPOSE:To compact a suction system obtaining a high resonance effect in a broad range by integrally forming a high speed suction passages whose practical air passing length is set to be short and low sped suction passages whose practical air passing length is set to be long. CONSTITUTION:In middle and low speed ranges to utilize a resonance effect, a communication passage closing valve 37 is closed and high speed suction passage closing valves 31 and 32 are opened in running at specified high speed. This generates resonance pressure waves in high speed suction passages 21 and 22 whose practical air passing length is set to be short regarding the spread of pressure waves. In addition, the communication passage closing valve 37 and high speed suction passage closing valves 31 and 32 are closed in running at specified low speed. This makes the pressure waves spread reciprocally between a suction port and low speed suction passage junction section 24 passing through an independent suction passage 3, high speed suction passages 21 and 22 and low speed suction passages 25 and 26 in order. Thus, a titled suction system can be compacted enhancing charging efficiency by effectively utilizing resonance effect in a broad speed range.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an engine intake system, and in particular, two systems having different substantial intake path lengths regarding the propagation of pressure waves.
This invention relates to the compactness of the engine/engine intake system in which two types of intake passages are provided, and the two types of intake passages are selectively used depending on the engine speed, thereby achieving a high resonance effect over a wide rotation range.

[Prior Art] Multi-cylinder engines that perform pressure wave supercharging using inertia effects or resonance effects to increase charging efficiency are generally known.

Here, pressure wave supercharging due to inertial effect means that when the intake valve of each cylinder is opened, the negative pressure wave generated at the intake port is moved upstream at the speed of sound within the independent intake passage connected to the intake port. The negative pressure wave is inverted into a positive pressure wave in this volume, and this positive pressure wave is propagated downstream at the speed of sound through the same intake path as above, and the intake air is generated just before the intake valve is closed. This is a supercharging method in which the intake air is forced into the combustion chamber by the positive pressure wave, increasing the charging efficiency. Since the independent intake passages of each cylinder must be set relatively short due to layout constraints, the time required for the pressure waves to propagate back and forth is relatively short, and the above inertial effect is reduced by the opening of the intake valve. It has the characteristic of being effective in a relatively high rotation range where the valve time is short.

On the other hand, pressure wave supercharging using the resonance effect involves forming multiple cylinder groups consisting of several cylinders with discontinuous ignition timing, and creating independent intake passages for each cylinder belonging to each cylinder group. They are gathered into one resonant intake passage upstream, and a pressure reversal section is provided at a predetermined position of this resonant intake passage, so that the pressure waves of each cylinder that propagate back and forth between each cylinder and the pressure reversal section are transmitted within the resonant intake passage. This is a supercharging method that generates resonance pressure waves with a larger amplitude than the pressure vibrations that occur individually in each cylinder, and uses these resonance pressure waves to force intake air into the combustion chamber to increase charging efficiency. be.

In this case, the pressure wave propagation path length is longer than the pressure wave propagation path length due to the inertial effect by the amount of the resonant intake passage, so
The resonance effect has a characteristic that it is effective in the middle and low rotation ranges where the intake valve opening time is relatively long. However, with such conventional intake devices, the resonance effect only increases in a relatively narrow rotation range corresponding to the intake path length, so the resonance effect is effectively utilized in a wide rotation range (medium and low rotation range). The problem was that I couldn't do it.

Therefore, regarding the propagation of pressure waves, the resonant intake passage is divided into two types: a high-speed intake passage with a short effective intake path length, and a low-speed intake passage with a long actual intake path length. In the engine speed range (medium/low speed range) where the resonance effect is utilized, the high-speed intake passage is used to enhance the resonance effect at relatively high speeds, while the low-speed intake passage is used to enhance the resonance effect at relatively low speeds. An engine intake system has been proposed that has a high rotation speed and can obtain a high resonance effect over a wide rotation range (for example, Japanese Patent Laid-Open No. 62-21
(See Publication No. 0219).

[Problems to be Solved by the Invention] In recent years, as car models with low bonnets have been preferred, the space above the engine has tended to become narrower, and there has been a demand for a more compact intake system to be placed in this space. There is.

However, since an intake system with two types of resonant intake passages, one for high speeds and one for low speeds, becomes large, there is a problem that the layout of the intake system becomes extremely difficult, especially for car models with low bonnets. . In a V-type engine, in order to equalize the independent intake passage lengths of both banks, the intake systems of each bank are normally placed above the corresponding banks, but in this case, the intake systems are placed under the bonnet. Since they must be arranged so that they do not touch each other, the layout becomes difficult. In particular, with a horizontally mounted V-type engine, if the intake system of each bank is placed above both banks, the intake system of the bank located on the front side of the vehicle should be placed because the bonnet is lower on the front side of the vehicle. There is a problem in that it is extremely difficult to arrange it so that it does not touch the bonnet.

Therefore, a method that can be considered is to arrange the intake system in the V-shaped space between both banks. Although this makes the intake system more compact to some extent, it reduces the length of the independent intake passage or the resonant intake passage. There is a problem that it becomes impossible to secure a sufficient amount of heat, and it becomes impossible to sufficiently enhance the inertial effect or the resonance effect.

The present invention has been made in view of the above-mentioned conventional problems, and in an engine equipped with a high-speed intake passage and a low-speed intake passage as described above, pressure waves caused by inertial effect or resonance effect over a wide rotation range are generated. It is an object of the present invention to provide an intake device with a compact configuration that can effectively perform supercharging and can be easily laid out even in a vehicle with a low hood.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a high-speed intake passage in which the substantial intake path length is set to be relatively short with respect to the propagation of pressure waves, and a downstream end of the high-speed intake passage. connected to the intake passage for
In an engine provided with a low-speed intake passage whose substantial intake path length is set longer than the above-mentioned high-speed intake passage,
An intake system for an engine, characterized in that the above-mentioned high-speed intake passage and the above-mentioned low-speed intake passage are integrally formed, and each bank is composed of cylinders having non-consecutive ignition timings,
Regarding the propagation of pressure waves, there is a high-speed intake passage whose effective intake path length is set to be relatively short, and the downstream end is connected to the high-speed intake passage, and the actual intake path length is set to be shorter than the high-speed intake passage. In a V-type engine that is provided with a long low-speed intake passage, each high-speed intake passage and each low-speed intake passage of both banks are arranged so that the vertical positions of the high-speed intake passages are different from each other. are both arranged above one bank, and the low-speed intake passage connected to the high-speed intake passage located at a lower position is arranged above the high-speed intake passage, while the one located at a higher position is connected to the high-speed intake passage. To provide an engine intake device characterized in that a low-speed intake passage connected to one high-speed intake passage is disposed on the side of the high-speed intake passage.

[Operations and Effects of the Invention] According to the configuration according to claim 1 of the present invention, regarding the propagation of pressure waves, the high-speed intake passage has a short substantial intake path length, and the high-speed intake passage has a long substantial intake path length. Since the low-speed intake passage and the low-speed intake passage are integrally formed, the high-speed intake passage and the low-speed intake passage can be switched depending on the engine speed.
While achieving a high resonance effect over a wide rotation range, the intake system can be made more compact, effectively responding to the trend toward lower bonnets in automobiles.

Further, according to the structure of claim 2, each high-speed intake passage and each low-speed intake passage of both banks are arranged above one bank, but such an intake system is arranged horizontally in the V type engine, if the intake system, such as the high-speed intake passage and low-speed intake passage, is placed above the bank on the rear side of the vehicle, the bonnet will be higher in this position, so the intake system It is easy to create a layout that prevents contact between the front and the bonnet. In addition, since the low-speed intake passage connected to the high-speed intake passage placed at a higher position is placed on the side of the high-speed intake passage, the height of the intake system can be suppressed, and the low-speed intake passage can be It is possible to effectively deal with the tendency to become a bonnet. On the other hand, the low-speed intake passage connected to the high-speed intake passage located at a lower position is formed in the remaining space above the high-speed intake passage, so the space in the engine room can be effectively utilized. This can be used to make the intake system more compact. Furthermore, since the low-speed intake passages of both banks can be arranged at approximately the same height, manufacturing becomes easy when these low-speed intake passages are integrally formed.

[Example] Examples of the present invention will be specifically described below.

As shown in FIG. 2, the 6-cylinder horizontal V-type engine CE, in which the first to sixth cylinders #l to #6 are ignited in order, has the first to sixth cylinders #l to #6 whose firing order is not consecutive. 3rd and 5th cylinder #1. #3. #5
is located in the front side bank F when viewed in the longitudinal direction of the vehicle, while the second ignition order is not consecutive. 4th. 6th cylinder #2. #4. #6 is placed in the rear bank R.

For example, when the intake valve l is opened, the first cylinder #l sucks intake air into the combustion chamber 4 from the independent intake passage 3 through the intake port 2, and transfers this intake air to the piston (not shown).
compress it, ignite it with a spark plug (not shown), and burn it.
When the exhaust valve 5 is opened, the combustion gas is discharged through the exhaust port 6 into the independent exhaust passage 7. A fuel injection valve 8 for injecting fuel is arranged with its injection port inclined toward the downstream side. Fuel is supplied to the fuel injection valve 8 through a fuel supply passage 9. Further, blow-by gas is introduced into the combustion chamber 4 through a blow-by gas passage 10 (see FIG. 1).

Note that the second to sixth cylinders #2 to #6 have a similar configuration.

The engine CE has a bonnet B that is formed with a gentle slope that becomes higher toward the rear of the vehicle.
In the engine room ER on the lower side of the N, both banks F and H are arranged with their axes facing in the vehicle width direction (so-called horizontal placement). A common intake passage 11 is connected between the upper end of the cylinder S of the rear side bank R and the bonnet BN via the throttle body 14 (see FIG. 1).
An intake manifold IM (see FIG. 1) connected to the intake manifold IM is arranged. At the top of the rear bank R, the bonnet B
N is quite high, and the space above the cylinder head S is secured with a relatively large margin in the vertical direction, so the intake manifold! M can be placed without interfering with the bonnet BN. This intake manifold! M is composed of a manifold main body M and an independent intake passage N, and this manifold main body M acts as a surge tank for stabilizing the supply of intake air, as will be described in detail below, and also serves as a surge tank for stabilizing the supply of intake air. - At low speeds, it acts as a resonance passage to effectively produce a resonance effect, and at high speeds, it acts as a volume part to effectively produce an inertial effect. Further, the independent intake passage section N is composed of six independent intake passages 3 each connecting the manifold main body section M and the intake boat 2 of each cylinder #l to #6.

The manifold body M includes a front high-speed intake passage 21 extending in the vehicle width direction, a front low-speed intake passage 25 arranged along the rear side surface of the front high-speed intake passage 21, and a front high-speed intake passage 21 extending in the vehicle width direction. A rear high speed intake passage 22 extending in the vehicle width direction substantially parallel to the rear side at a slightly lower position, and a rear low speed intake passage 26 disposed along the upper surface of the rear high speed intake passage 22 are provided. The downstream end of the front high-speed intake passage 21 and the downstream end of the rear high-speed intake passage 22 are connected to a communication passage 33 (see FIG. 1).
These three intake passages 21,
22.33 forms a substantially U-shaped intake passage (the first
), the communication passage 33 has a communication passage opening/closing valve 37 (see Figure 1) that opens and closes depending on the operating state of the engine CE.
is provided. In addition, the front side low speed intake passage 2
The downstream end of the rear high-speed intake passage 26 is connected to the front high-speed intake passage 21 from the side (see FIG. 1 27), and the downstream end of the rear low-speed intake passage 26 is connected to the rear high-speed intake passage 22 from above. (See Fig. 1, 28).

These front and rear high-speed intake passages 21°22
The upstream end of the front and rear low-speed intake passages 25 and 26 are opened to the flange 18 via the common low-speed intake passage 23 (the first (see figure).

On the other hand, front cylinder #1. #3. The upstream end of the #5 independent intake passage 3 is connected to the front side surface of the front high-speed intake passage 21, and these independent intake passages 3 extend almost linearly from here while gradually descending toward the front. After that, it curves vertically downward and is connected to the intake boat 2 of the corresponding cylinder in the front bank F.

Also, the rear cylinder #2. #4. The upstream end of the #6 independent intake passage 3 is connected to the front side surface of the rear high-speed intake passage 22, and these independent intake passages 3 are curved upwardly in the front direction from here. Stretch,
The downstream portion extends substantially downward and is connected to the corresponding intake boat 2 of the rear bank R.

The configuration of each part of the intake device will be explained in more detail below.

As shown in FIG. 1, in order to effectively utilize the space above the engine CE, the common intake passage 11 is formed into a slightly flattened shape in the vertical direction and whose cross section is formed into a horizontally elongated substantially rectangular shape. , branch part 2, front side branch intake passage 1
1f and a rear branch intake passage 11r. The downstream end portions of these front side and rear side branch intake passages 11Lllr are connected to the seven rung portion 18 of the manifold main body portion M via the throttle body 14.

Inside the throttle body 14, there are a front throttle valve 13f that adjusts the throttle amount of intake air in the front branch intake passage 11f, and a rear throttle valve 13r that adjusts the throttle amount of intake air in the rear branch intake passage 11r. It is provided. These front side and rear side throttle valves 13
f and 13r are each attached to a valve shaft 15 within the throttle body 14, and are integrally opened and closed via a link mechanism 16 having non-linear opening characteristics in response to depression of an accelerator pedal (not shown). It has become so.

In the seven rungs 18 of the manifold main body M, the front intake passage 11f and the rear intake passage 11r are assembled again to form a gathering section 17 (see FIG. 4). This gathering portion 17 utilizes the phenomenon that the pressure is almost equalized due to the interference between the intake pulsation of the intake system on the front side bank F side and the intake pulsation of the intake system on the rear side bank R side, and produces a resonance effect. It is provided to form an inversion part (open end) of pressure waves when used. Immediately downstream of the gathering portion 17, the intake system branches into a front high-speed intake passage 21, a rear high-speed intake passage 22, and a common low-speed intake passage 23, as will be explained in detail later. There is. In this case, the front side and rear side high speed intake passages 21.
22 opens in the lower half of the collecting part 17 having a horizontally long rectangular cross section, and a common low-speed intake passage 23 opens in the center of the upper half of the collecting part 17 (see FIG. 2). Furthermore, the common low-speed intake passage 23 connects to the front-side low-speed intake passage 25 at a low-speed intake passage branching portion 24 located slightly downstream of the gathering portion 17.
and a rear low-speed intake passage 26. In addition,
The passage cross-sectional area of the front and rear high-speed intake passages 21.22 is sufficient compared to the passage cross-sectional area of the front and rear low-speed intake passages 25.26 so that a large amount of air can be supplied at high speed. Set it large. The downstream end of the front low-speed intake passage 25 is laterally connected to the front high-speed intake passage 21 at the front connection part 27, while the downstream end of the rear low-speed intake passage 26 is , is connected from above to the rear high-speed intake passage 22 at a rear side connecting portion 28. Therefore, at low speed, the low speed intake passage 2
The intake air of 5.26 once flows into the high-speed intake passages 21 and 22, is dispersed there, and is then supplied from each independent intake passage 3 to the corresponding cylinder. In other words, the high-speed intake passage 21
゜22 functions as a kind of surge tank at low speeds.

The front side surface of the front high-speed intake passage 21 is provided with first, third, . Fifth
Cylinder #1. #3. A #5 independent intake passage 3.3.3 is connected to the front side surface of the rear high-speed intake passage 22. 4th. 6th cylinder#
2, #4, and #6 independent intake passages 3, 3.3 are connected. The positional relationship between the front high-speed intake passage 21 and the rear high-speed intake passage 22 and the longitudinal shape of each independent intake passage 3 are as follows: Independent intake passage 3 of side bank R
, 3°3 have the same intake path length.

Immediately downstream of the gathering portion 17, the front and rear high-speed intake passages 21 and 22 are provided with front and rear high-speed intake passage opening/closing valves 31 and 22, respectively, which open and close these.
32 are provided. These front and rear high-speed intake passage opening/closing valves 31 and 32 are designed to close when the engine speed is below a predetermined value in the engine speed range where the resonance effect should be utilized, as will be explained later. It has become.

Figure 3 is the intake manifold! 4 is a cross-sectional explanatory diagram taken along the line X--X in FIG. 3. FIG. As shown in FIGS. 3 and 4, from the lower half of the seven rung portion 18 (collecting portion 17), a front high-speed intake passage 21 and a rear high-speed intake passage 2 are connected.
2 branch and extend downstream, and a common low-speed intake passage 23 branches and extends downstream from the upper half of the gathering portion 17.

As shown in FIG. 1 again, on the downstream side from the gathering part 17,
The front high-speed intake passage 21 and the rear high-speed intake passage 22 gradually widen left and right and extend downstream from the position corresponding to the first cylinder #1 to the second cylinder #2. , these extend parallel to each other. Then, the part where these extend parallel to each other (hereinafter referred to as
In this portion (this portion is referred to as a parallel portion), the front high-speed intake passage 21 is located at a slightly higher position than the rear high-speed intake passage 22 (see FIG. 8). In addition, on the downstream side from the low-speed intake passage branch part 24, the 70-ton side low-speed intake passage 25 and the rear-side low-speed intake passage 26 gradually widen in the left-right direction and extend toward the downstream. In the parallel portion, the front low-speed intake passage 25 is integrally formed with the front high-speed intake passage 21, sharing the flat rear side wall thereof, while the rear low-speed intake passage 26 is formed integrally with the rear high-speed intake passage 21. It is integrally formed by sharing the planar earthen wall of the passageway 22.

The front and rear high-speed intake passages 21.2 extend from the flange portion 18 (gathering portion 17) to the parallel portion.
2 and the front side and rear side low-speed intake passages 25 and 26, the cross-sectional view taken along the line A-A, the cross-sectional view taken along the line B-B, and the cross-sectional view taken along the line C-C in FIG. Line sectional view and D-
D-line sectional views are shown in FIG. 5, FIG. 6, FIG. 7, and FIG. 8, respectively. That is, each intake passage 21.22.25
゜26 gradually moves from the flange portion 18 to the front side.

It is separated to the rear side and reaches the parallel part (Fig. 8).

As shown in Fig. 8, in the parallel part, the front side,
The passage cross-sectional area of the rear low-speed intake passages 25.26 is set to be considerably smaller than the passage cross-sectional area of the front and rear high-speed intake passages 21.22. As will be explained in detail later, this allows the front side to
The substantial intake path length of the rear low speed intake passages 25.26 is longer than the substantial intake path length of the front and rear high speed intake passages 21.22. Note that the cross-sectional shape of the front-side high-speed intake passage 21 is such that the length in the width direction is smaller than the length in the vertical direction in order to suppress the height of the intake system.

Further, the front high-speed intake passage 21 is arranged at a position such that its lower surface is approximately at the same height as the upper surface of the rear high-speed intake passage 22. And, as mentioned above,
The low speed intake passage 25 on the front side shares the rear side wall of the front high speed intake passage 21 and is formed integrally therewith, while the rear low speed intake passage 26 is formed integrally with the rear side wall of the front high speed intake passage 21. Since they share the earthen wall of the passageway and are formed integrally with it, they have a very compact shape with suppressed height. In addition, since the front low-speed intake passage 25 and the rear low-speed intake passage 26 are arranged at almost the same height, the front low-speed intake passage 25 and the rear low-speed intake passage 26 are manufactured integrally. The rear low-speed intake passage 26 can be manufactured very easily.

Further, as shown in FIG. 9, the front side high-speed intake passage 21 has a second intake passage extending from the rear side so as to intersect with the front side high-speed intake passage 21.
4th. 6th cylinder #2. #4. #6 each independent intake passage 3,
3.Since it is integrally formed by sharing the earthen wall of 3,
The structure of the intake system has become more compact and has increased rigidity.

By the way, as shown in FIG. 1 again, the downstream end of the front high-speed intake passage 21 and the rear high-speed intake passage 2
The downstream end of No. 2 is connected to the downstream end of No. 2 by a substantially U-shaped communication path 33. In the vicinity of the connection with the rear high-speed intake passage 22, the communication passage 33 is provided with a communication passage opening/closing valve 37 for opening and closing the communication passage 33. This communication passage opening/closing valve 3
7 is opened to form a volume part (pressure reversal part) when the inertial effect is utilized in a predetermined high rotation range, as will be explained later.

As shown in FIG. 1O, an opening 38 is formed in the bent part (bottom part of the letter 0) at the downstream end of the communication path 33, and this opening 38 is used to attach a plastic cover member 39 to the bolt. etc., so that it can be closed during normal times. This opening 38 is designed so that the valve body of the communication passage opening/closing valve 37 can be easily inserted or removed from here during assembly or repair, or from here into the front side and rear high speed intake passages 21 and 22. It has a shape that is wide open on the left and right so that cleaning etc. can be done easily.

Hereinafter, pressure wave supercharging performed in the above configuration will be explained with reference to FIG.

In a predetermined high speed range where the inertial effect is to be utilized, the communication passage opening/closing valve 37 and the front and rear high speed intake passage opening/closing valves 31.
32 will be held together. At this time, the front and rear high-speed intake passages 21 and 22 communicate with each other via a communication passage 33, and these integrally form a volume portion having a considerably large volume, and this volume portion is a pressure wave reversal area. It acts as. When the intake valve 1 of each cylinder #1 to #6 is opened, the negative pressure wave generated in the intake port 2 propagates upstream through the independent intake passage 3 at the speed of sound, and The high-speed intake passages 21 and 22 are connected to each other and the volume is inverted into a positive pressure wave, and this positive pressure wave propagates downstream through the independent intake passage 3, and immediately before the intake valve 1 is closed, the air pressure wave reaches the intake port. 2, this positive pressure wave forces the intake air into the combustion chamber 4, increasing the charging efficiency (inertia effect).

On the other hand, in the middle/low speed range where the resonance effect is to be utilized, at a predetermined high speed, the communication passage opening/closing valve 37 is closed, while the front side and rear side high speed intake passage opening/closing valves 31, 32 are opened. At this time, the front high-speed intake passage 21 and the rear high-speed intake passage 22 do not communicate with each other, so a volume portion (pressure reversal portion) is not formed as is the case when the inertia effect is utilized.

For example, the first bank belonging to the front side bank F. Third
．． 5th cylinder #1. #3. Regarding #5, the negative pressure wave generated when the intake valve 1 is opened sequentially connects to the independent intake passage 3,
It propagates at the speed of sound via the front-side high-speed intake passage 21 to the gathering portion 17. By the way, this gathering section 17 is arranged for each cylinder #1. belonging to the front side bank F. #3. Pressure waves generated from #5 and each cylinder #2 belonging to rear bank R
, #4, and #6 interfere with each other to form a pressure uniform portion, and such a pressure uniform portion acts as a pressure reversal portion in the propagation of the pressure waves. Therefore, each cylinder #1 of the front side bank F. #3
．． The negative pressure wave generated at #5 and propagated to the collecting section 17 is reversed into a positive pressure wave at the collecting section 17, and is then transferred to the front side high-speed intake passage 21 and the first. Third. 5th cylinder #l, #3. Each cylinder #l via each independent intake passage 3 of #5.

#3. It reaches intake port 2 of #5. Such a pressure wave propagation phenomenon is caused by the first wave belonging to the front side bank F. Third. 5th cylinder #1. #3. #5, so in the high-speed intake passage 21, each cylinder #1, #3. The #5 pressure waves resonate with each other, and a resonant pressure wave is generated that has a larger amplitude than the vibration of the pressure wave generated in one cylinder. In the cylinder in which such a resonance pressure wave reaches the intake port 2 immediately before the intake valve 1 is closed, the intake air is pushed into the combustion chamber 4 by the resonance pressure wave, thereby increasing the charging efficiency (resonance effect). In this case, the front low-speed intake pipe 25 also communicates each intake port 2 with the gathering portion 17, but as described above, the front low-speed intake passage 25 has an inner diameter that is equal to the front high-speed intake passage. 21, only the front high-speed intake passage 21 is effective in propagating pressure waves, and the front low-speed intake passage 25 has no substantial effect. Note that each cylinder #2 belonging to the rear side bank R. #4. For #6, pressure wave supercharging is similarly performed due to the resonance effect.

Further, in the medium/low speed range where the resonance effect is to be utilized, at a predetermined low speed, both the communication passage opening/closing valve 37 and the front side and rear side high speed intake passage opening/closing valves 31, 32 are closed. At this time, the front side.

Since the rear high-speed intake passages 21 and 22 are closed on the upstream side, for example, each cylinder #1 on the front bank F side.
#3. For #5, the pressure waves in turn
and each cylinder #1. #3. #5
It propagates back and forth between the intake port 2 and the low-speed intake passage branch part 24. In this case, the front cylinder #1. #
3° #5 and rear cylinder #2. #4. Due to intake interference with #6, the low-speed intake passage branch portion 24 becomes a pressure equalization portion, that is, a pressure inversion portion. In this way, the propagation path of pressure waves becomes longer, and since the front side low-speed intake passage 25 is set to have a smaller inner diameter than the front side high-speed intake passage 21, the equivalent pipe length for pressure wave propagation is Therefore, the time required for the pressure wave to propagate back and forth becomes longer, and the resonance effect can be effectively enhanced at relatively low speeds, and the filling efficiency can be improved.

As described above, according to the present invention, it is possible to effectively utilize the inertia effect and the resonance effect over a wide rotation range to increase the filling efficiency and to make the intake device more compact.

[Brief explanation of the drawing]

FIG. 1 is an explanatory plan view of an intake system for a six-cylinder horizontal V-type engine, showing an embodiment of the present invention. FIG. 2 is an explanatory elevational view of an engine equipped with the intake device shown in FIG. 1. FIG. 3 is an explanatory elevational view showing a portion of the intake device shown in FIG. 1 downstream from the collecting section. FIG. 4 is an explanatory cross-sectional view taken along the line X--X in FIG. 3. FIG. 5 is an explanatory cross-sectional view taken along line A-A of the intake device shown in FIG. 1. 6 is an explanatory cross-sectional view taken along line B-B of the intake device shown in FIG. 1. FIG. FIG. 7 is an explanatory cross-sectional view taken along the line CC of the intake device shown in FIG. 1. FIG. 8 is an explanatory cross-sectional view taken along line D-D of the intake device shown in FIG. 1. FIG. 9 is a diagram showing the positional relationship among the front and rear high-speed intake passages, the front and rear low-speed intake passages, and the independent intake passages in the parallel portion of the intake system shown in FIG. 1. . FIG. 1O is an explanatory elevational view of the communication passage viewed from the downstream side with the lid member removed. CE...6-cylinder horizontal V-type engine, F...front side bank, R...rear side bank, IM...intake manifold, M...manifold body, N...independent intake passage Part, BN...Bonnet, #l~#6...
・1st to 6th cylinders, l...intake valve, 2...intake port, 3...independent intake passage, 11...common intake passage,
llf, 11r... Front side, rear side branch intake passage, 12... Branch part, 14... Throttle body, 1
7... Collection part, 18... 7 rung part, 21... Front side high speed intake passage, 22... Rear side high speed intake passage, 23... Common low speed intake passage, 25...・Front side low speed intake passage, 26...Rear side low speed intake passage, 31...Front side high speed intake passage opening/closing valve, 32
...Rear side high speed intake passage opening/closing valve, 33...Communication passage, 37...Communication passage opening/closing valve. Figure 1

Claims (2)

[Claims] (1) Regarding the propagation of pressure waves, the effective intake path length is set to be relatively short, and the downstream end is connected to the high speed intake path, and the effective intake path length is set to be relatively short. An intake system for an engine, characterized in that the engine is provided with a low-speed intake passage that is longer than the intake passage, wherein the high-speed intake passage and the low-speed intake passage are integrally formed. (2) For each bank composed of cylinders with discontinuous ignition timing, there is a high-speed intake passage whose effective intake path length is set to be relatively short in terms of pressure wave propagation, and a downstream end that is In a V-type engine that is connected to a high-speed intake passage and a low-speed intake passage whose effective intake path length is longer than the high-speed intake passage, the vertical positions of the high-speed intake passages are different from each other. In this way, each high-speed intake passage and each low-speed intake passage of both banks are arranged above one bank, and the low-speed intake passage is connected to the high-speed intake passage located at a lower position. is arranged above the high-speed intake passage, while the low-speed intake passage connected to the higher-speed intake passage is arranged on the side of the high-speed intake passage. Engine intake system.