JPH0232862Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an improvement of an intake system for a V-type engine having two banks.

(Prior art) Conventionally, in a V-type engine, the intake ports of each cylinder for two banks were formed so as to face each other inside both banks, and the intake ports were connected to independent intake passages. The structure of the intake system is known, for example, as seen in US Pat. No. 2,845,912.

In addition, in general, filling efficiency is increased by utilizing dynamic effects of intake air such as intake inertia and resonance, that is, pressure waves.
It is known to configure the intake system so as to obtain high output through this. However, in order to configure such an intake system, it is necessary to provide the intake system with a pressure wave inversion part, that is, a surge tank, to reverse the negative pressure waves generated in the intake system and guide them to the combustion chamber. In order to guide pressure waves into the combustion chamber at the correct timing, an intake passage of the required length must be secured downstream of the above-mentioned reversal section, and as the intake device becomes larger, it is required to be compact. . However, if the curvature of the intake passage is increased for the sake of compactness, the passage resistance of the intake passage increases, which becomes an obstacle to ensuring a high intake flow rate.

Therefore, for example, an intake system structure is proposed in which the intake passage communicating with the intake port of each cylinder of a V-type engine is curved to the upper part of one bank, and a surge tank is arranged in this part to connect the end of the intake passage. Conceivable. In this structure, a surge tank is disposed in the space above one bank, and the intake passage that branches from the surge tank and communicates with each cylinder is curved, so the surge can be adjusted to accommodate the slope of the bonnet. Although a tank can be installed and the overall height of the engine can be made low and compact, it is difficult to assemble the intake system.

In other words, when the intake ports of each cylinder open on the opposing inner sides of both banks, and the intake passage is curved from the surge tank placed on one bank and connected to each intake port as described above, the surge The tank and the curved intake passage become obstacles to the assembly work, and it is difficult to find a place where the assembly bolts for attaching the intake passage can be easily tightened.

In addition, since the intake passages of each cylinder are all curved onto one bank, the intake passages are arranged in parallel at the top of one bank, and there is no gap between the intake passages, and the injector is placed near the intake port of each cylinder. If this injector is installed, it becomes difficult to confirm the operation of the injector. In other words,
Normally, the operation of an injector is checked by touching the tip of a sounding rod to the injector and listening to the operating sound transmitted through the sounding rod. In the structure of the device,
The upper part of the injector is covered by an intake passage,
An insertion gap for abutting the sound detection rod against the injector is not formed, which may make the work complicated.

(Purpose of the invention) In view of the above-mentioned circumstances, the present invention has been developed to connect the intake passages to the intake ports of each cylinder, which are formed to face each other inside both banks, and the surge tank arranged on one bank, respectively. It is an object of the present invention to provide an intake system for a V-type engine, which has a structure of a surge tank and an intake passage having the required characteristics, and which improves the ease of assembly and the workability of checking the operation of an injector. .

(Structure of the invention) The intake device of the invention has independent intake passages connected to intake ports formed inside both banks so as to face each other, and gathers them in a surge tank arranged above one bank. The independent intake passages include a substantially horizontal connecting flange portion, and the independent intake passages are connected to the connecting flange portions in line according to a predetermined interval between cylinders, and the independent intake passages immediately upstream from the connecting flange portions are Curve some parts,
The present invention is characterized in that a gap is provided between the independent intake passages that is wider than the connection interval at the connecting flange portion, and a mounting bolt for fastening one side portion of the connecting flange portion is arranged in this gap.

(Effects of the invention) According to the invention, each independent intake passage connected to the intake ports of both banks is configured to converge in a surge tank placed above one bank. It is possible to secure the desired length of the intake passage on the downstream side of the surge tank and connect it to the surge tank without increasing the curvature, and it is also possible to reduce the amount of protrusion of the intake system above the engine. This increases the degree of freedom in layout, design, etc. in relation to the bonnet.

Furthermore, a portion of the independent intake passages immediately upstream of the connection flange portion is formed into a curved shape to provide a gap between the independent intake passages that is wider than the connection interval at the connection flange portion, and one side of the connection flange portion is provided between the independent intake passages. By arranging the mounting bolts that fasten both sides, it is easy to assemble the independent intake passage without increasing the length of the connecting flange, improving work efficiency. In this case, a sound detection rod for checking the operation of the injector can be inserted through the above-mentioned gap, and the work of checking the operation of the injector can be carried out easily.

(Example) Hereinafter, an example of the present invention will be described along with the drawings. Figure 1 is a side view partially showing the upper structure of a 6-cylinder V-type engine equipped with an intake system;
The figure shows its plan view. The V-type engine in this example is an example of a so-called horizontal type engine that is placed in the engine room formed at the front of the vehicle body so that its output shaft is oriented horizontally. The lower side in Figure 2 is the front of the vehicle.

A six-cylinder V-type engine 1 has a front cylinder head 3 and a rear cylinder head 4 arranged obliquely on a cylinder block 2 at the lower center, and cylinders C ₁ to _{C 6} ( In FIG. 2, a front bank 1A and a rear bank 1B having cylinders 1 to 6 in order from the right are formed. That is, the cylinders C ₁ to C ₆ are arranged in a V-shape at a predetermined angle, and the six cylinders C ₁ to _{C 6} are alternately divided into two groups of three cylinders each: odd-numbered cylinders and even-numbered cylinders. Front and rear banks 1A, 1B
It consists of Two banks 1A, 1B cylinders
C ₁ to _{C 6} are arranged offset from each other in the output shaft direction (horizontal direction in Fig. 2), and correspondingly, the front cylinder head 3 is positioned to the right of the rear cylinder head 4 when viewed from the front. They are placed out of alignment.

An intake port 8 and an exhaust port (not shown) are opened in the combustion chamber 7 formed above the piston 5 of each of the cylinders _C1 to _C6 , and both ports are connected to an intake valve 9 and an exhaust valve (not shown), respectively. (not shown) opens and closes at predetermined timing. The above-mentioned intake port 8 in the front and rear cylinder heads 3 and 4
are formed with openings facing each other on the inner surface side. Head covers 3a and 4a are attached to the upper portions of the front and rear cylinder heads 3 and 4 to cover the valve mechanism and the like.

Each cylinder in the front and rear banks 1A and 1B on both sides of the above
The intake device that supplies intake air to C ₁ to _{C 6} includes an intake manifold 6 that constitutes front and rear independent intake passages 10 and 11 connected to each intake port 8 of cylinder heads 3 and 4 on both sides, respectively, and a rear bank. 1B, the independent intake passage 10,
The upstream end of the surge tank 11 is connected to the surge tank 12.

The surge tank 12 is configured as a box-like body that is long in the output shaft direction, that is, in the lateral direction of the vehicle, and is divided into upper and lower sections, an upper surge tank 13 and a lower surge tank 14, by a partition wall 15 that extends in a substantially horizontal direction. divided into spaces. The front independent intake passage 10 from the front bank 1A that is farther from the surge tank is connected to the lower surge tank 14, and the rear independent intake passage 11 from the rear bank 1B that is closer to the upper surge tank 13 is connected to the lower surge tank 14. are connected, and independent intake passages 10 and 11 are assembled for each bank 1A and 1B.

Further, the independent intake passages 10 and 11 are divided by a substantially horizontal connecting surface F at the upper middle of the banks 1A and 1B on both sides, and the upstream surge tank side passages 10a and 11a are connected to the surge tank 12.
and a downstream intake port side passage 10b, 11b connected to the intake port 8.

That is, the front independent intake passage 10 connected to the front bank 1A extends obliquely rearward and upward toward an intermediate position between both the banks 1A and 1B via the intake port side passage 10b, and extends through the substantially horizontal connecting surface F. The surge tank side passage 10a extends from above to the rear with a slight curvature and further slightly downward, and is laterally connected to the lower surge tank 14 of the surge tank 12 located above the rear bank 1B. On the other hand, the rear independent intake passage 11 connected to the rear bank 1B extends obliquely forward and upward toward the substantially same position between both the banks 1A and 1B through the intake port side passage 11b, and is connected to the common connection surface. The surge tank side passage 11a extends rearward from above substantially horizontally with a slight curvature via F, and is connected to the upper surge tank 13 of the surge tank 12 from the side. The above connection structure prevents large bending of the independent intake passages 10 and 11 due to reverse connection,
Suppresses the increase in intake resistance.

Furthermore, the connection positions of the independent intake passages 10 and 11 to the upper and lower surge tanks 13 and 14 correspond to the fact that the front bank 1A is shifted to the right side from the rear bank 1B, and the front independent intake passages 10 and 11 are connected to the lower surge tank 14. The connection position of the passage 10 is shifted to the right side from the connection position of the rear independent intake passage 11 with respect to the upper surge tank 13. Accordingly, the right side of the upper surge tank 13 is formed low, and a communication control valve 27, which will be described later, is provided at the left end of the lower surge tank 14.

A portion of the surge tank side passages 10a, 11a of each of the independent intake passages 10, 11 is such that the passages 10a of the first and third cylinders _C1 , _C3 are on the right side when viewed from above, as shown in FIG. 4th and 6th cylinder C ₄ ,
The passage 11a of _C6 is curved to the left, and a gap is formed on the left side of the surge tank side passage 10a of the odd numbered cylinders (front bank 1A) and the surge tank side passage 11a of the even numbered cylinder (rear bank 1B). It is formed. This gap is filled with mounting bolts 19, which will be described later.
is placed.

The upstream surge tank side passages 10a, 11a of the front and rear independent intake passages 10, 11 are formed integrally with the surge tank 12, and the intake port side passages 10b, 11b of each cylinder on the downstream side are connected to the mounting flange 10c at the downstream end. , 11c is the mounting bolt 20
are fixed to the front and rear banks 1A and 1B, respectively. In addition, the surge tank side passages 10a, 1
1a and the intake port side passages 10b, 11b are connected by joining upper and lower connecting flange portions 16, 17 common to each cylinder, which are formed substantially horizontally at the respective connecting ends, and the connecting flange portions 16, 17, each independent intake passage 10, 11 is lined up and connected to the intake passage 17 according to a predetermined interval between cylinders.

The connection flanges 16 and 17 are integrally formed so as to connect the connection ends of the surge tank side passages 10a and 11a and the intake port side passages 10b and 11b of all cylinders, respectively. Furthermore, when the connecting flanges 16 and 17 are fastened together using the front and rear mounting bolts 18 and 19, the rear boss portion 16a above which the surge tank side passages 10a and 11a curved backwards is , the surge tank side passage 10 immediately upstream of the connection flange portion 16
a, 11a are bent left and right on a plane, and a bolt is formed extending upward from the flange part 16 and formed high in the gap between the passages, which is wider than the connection interval at the connecting flange part 16. It is configured to be able to tighten 19 degrees.

On the other hand, the upper and lower surge tanks 13 and 14 of the surge tank 12 have upstream introduction passages 13a and 14a that extend to the right, curve forward in a cylindrical shape, and extend upwardly and downwardly to the throttle body 21, respectively. Throttle valves 22 and 23 installed above and below within the throttle body 21 control the respective intake flow rates. This throttle body 2
The intake passages 24 further upstream from 1 are merged on the upstream side (not shown) to form one main intake passage,
Connected to the air cleaner. Further, the surge tank 12 is connected and supported to the rear cylinder head 4 by a rear connecting fitting 25.

As shown in FIGS. 3 and 4, the upper surge tank 13 and lower surge tank 14 of the surge tank 12 communicate with each other via a communication passage 26 formed at the left end of the lower surge tank 14. A communication control valve 27 that changes the communication area in the middle of the communication path 26
is interposed. That is, the partition wall 15 below the connection opening portion of the independent intake passage 11 of the sixth cylinder C ₆ to the upper surge tank 13 is formed low toward the lower surge tank 14 side, and a communication passage 26 is formed in this portion. A shaft portion 27a of a butterfly-type communication control valve 27 is supported through the communication passage 26 in the front-rear direction, and the opening degree of the control valve 27 is changed and adjusted by the operation of an actuator 28. . The actuator 28 is controlled mainly in response to the engine speed, and its opening degree is adjusted to increase the communication area as the engine speed increases.

In addition, in order to discharge water generated by condensation or the like to the outside of the surge tank 12, the surge tank 12 is provided with a valve connected to the upper surge tank 13 through a communication passage 26 when the communication control valve 27 is in the open state. The water flows down into the lower surge tank 14 and is discharged together with the water in the lower surge tank 14 from a drain hole 29 formed at the bottom of the surge tank 12.

Furthermore, as shown in FIGS. 5 and 6, the intake system is provided with an EGR passage 30 that recirculates exhaust gas for NOx suppression. An EGR adapter 31 is disposed on the right side of the engine between the front and rear banks 1A and 1B, and inside this EGR adapter 31 is an EGR valve 3 that opens and closes the EGR passage 30.
A pipe 34 (see FIG. 2) that guides exhaust gas from an exhaust passage (not shown) is connected to the EGR adapter 31.

Guide the exhaust gas through the above EGR valve 33
The EGR passage 30 has a lead-out portion 30a from the EGR adapter 31 connected to the intake port side passages 10b, 11b.
The flange portion 17 of the surge tank is connected to the flange portion 16 of the surge tank side connectors 10a, 11a via the connecting surface F, and the intermediate portion 30b is connected to the first flange portion 17 of the intake manifold 6.
It is formed integrally with the surge tank side passage 10a of the independent intake passage 10 for the cylinder _C1 along the side thereof, and extends to the surge tank 12.
The downstream end of this EGR passage 30 is connected to the surge tank 1
The two upper and lower surge tanks 13 and 14 are communicated with each other through introduction portions 30c and 30d formed by drill holes in the upstream introduction passage portions 13a and 14a, respectively. This allows the exhaust gas to flow from both banks 1
The gas is refluxed to each cylinder C ₁ to C ₆ of A and 1B with good distribution evenly.

On the other hand, in the banks 1A and 1B on both sides, an intake port side passage 10 of each of the independent intake passages 10 and 11 is provided.
Mounting flanges 10c, 11 at the downstream end of b, 11b
An injector 36 for injecting fuel into the intake port 8 of each cylinder C ₁ to _{C 6} is installed at c. Fuel supply pipes 37, 37 arranged for each bank 1A, 1B are connected to the injector 36, and fuel is supplied thereto. Further, above the engine 1, a bonnet 38 that covers the engine room is arranged so as to be inclined downward from the rear toward the front.

In the 6-cylinder V-type engine 1 in this example, the ignition order is set in the order of 1-2-3-4-5-6 cylinders, with the 1st, 3rd, and 5th cylinders in the front bank 1A, and the 2nd, 4th, and 5th cylinders in the front bank 1A. Six cylinders each belong to rear bank 1B. Therefore, in the upper surge tank 13 and the lower surge tank 14, each surge tank 1
The intake order is not consecutive between the cylinders connected to cylinders 3 and 14, and no intake interference occurs.

Further, as described below, it is possible to improve the output by utilizing pressure waves in the intake passage upstream of the surge tank 12. That is, two banks 1A, 1
In the cylinders belonging to B, the negative pressure waves generated by the opening/closing operation of the intake valve 9 during the intake stroke have a phase relationship that is opposite to each other. The negative pressure waves generated in each cylinder are
The air propagates upstream through the independent intake passages 10 and 11, and reaches the upper and lower surge tanks 13 and 14, respectively. Independent intake passage 10, 1 downstream of the surge tank
1 is set to have the same length for each cylinder, so the pressure waves in the upper and lower surge tanks 13 and 14 are also shifted by half a wavelength between the cylinders belonging to the two banks 1A and 1B. The negative pressure waves reaching the upper and lower surge tanks 13 and 14 propagate upstream from the introduction passages 13a and 14a, respectively, and
Intake passage 2 on the upstream side via the throttle body 21
4 interfere with each other at the confluence point of the two waves, and the waves reverse and return to the combustion chamber 7 as a positive pressure wave. This inverted positive pressure wave provides a so-called resonance effect that increases the filling efficiency of intake air, thereby making it possible to obtain high output.

Furthermore, since the length of each independent intake passage 10, 11 downstream of the surge tank 12 can be ensured sufficiently, the output can be sufficiently improved due to the inertial effect using the pressure waves reflected by the upper and lower surge tanks 13, 14. Obtainable. Further, by adjusting the opening degree of the communication control valve 27, the volume effect of the upper and lower surge tanks 13, 14 is varied, and the characteristics of the inertial effect and the resonance effect are adapted to the rotational speed in a wide range.

According to the above embodiment, each independent intake passage 10, 1
1 is divided into surge tank side passages 10a, 11a and intake port side passages 10b, 11b, the connecting surface F of both is set approximately horizontal, and a part of the surge tank side passages 10a, 11a is curved. A gap is formed between the passages without increasing the connection interval at the connecting flange portion 16, and the mounting bolts 19 are arranged in this portion to attach the surge tank side passages 10a and 11a. The intake port side passages 10b and 11b of the cylinders are integrally connected by the flange portions 16 and 17, and similarly the surge tank side passages 10a and 11a of each cylinder are integrally constituted with the surge tank 12. gender has improved. That is, when assembling the intake port side passages 10b, 11b to the front and rear cylinder heads 3, 4, since there are no surge tank side passages 10a, 11a in the upper part, it is necessary to attach the mounting flanges 10c, 11c to the cylinder heads 3, 4 from above. The fastening work, the installation of the injector 36, the connection work with the fuel supply pipe 37, etc. can be easily performed. In addition, the above-mentioned intake port side passage 10
b, 11b and surge tank side passages 10a, 11a
Connection with the surge tank side passages 10a and 10a is made at connection flanges 16 and 17 formed approximately horizontally.
The mounting bolt 1 is also attached from above to the rear boss portion 16a disposed in the gap formed between the holes 11a and 11a.
This is done by tightening steps 8 and 19, and the work is easy.

When confirming the operation of the injector 36, a measuring rod (not shown) is inserted into each injector 36 of the rear bank 1B from the gap formed between the passages 10a, 11a by the curvature of some of the surge tank side passages 10a, 11a. This is confirmed by contacting the machine and listening to the sound of its operation.

On the other hand, in the above intake structure, the independent intake passage 10,
Since the curvature of 11 is small, the resistance of the intake air passage is small, and the problem of insufficient intake air does not occur at high rotation speeds. Further, since no intake device is arranged above the front bank 1A, the distance between the engine 1 and the bonnet 38 can be made sufficiently small. Note that the surge tank 12 is disposed above the rear bank 1B, and its upward protrusion is larger than the lower part of the front banks 1A and 1B.
Since the bonnet is inclined in this part, there is a relatively large space above the bonnet, and therefore, the intake device can be arranged without difficulty while ensuring a sufficient length of the intake pipe.

In addition, in the above embodiment, the case where the present invention is applied to a horizontally mounted V-type engine has been explained, but the present invention is not limited to this and can be similarly applied to various other V-type engines. It is something that can be done.

Further, the surge tank may be arranged not only above and below as in the above embodiment, but also may be arranged front and back, or may be integrated into both banks without being divided.

[Brief explanation of the drawing]

FIG. 1 is a left side view showing a partial cross section of the main part of a V-type engine equipped with an intake system according to an embodiment of the present invention, FIG. 2 is a plan view of the main part, and FIG.
Figure 4 is a cross-sectional view taken along the line - in Figure 3, Figure 5 is a plan view of the main part showing the structure of the EGR passage that recirculates exhaust gas, and Figure 6 is a cross-sectional view of the layer taken along the line - in Figure 3. 5 is a cross-sectional view showing the side structure of the EGR passage along with the negative cross-section in FIG. 5. FIG. 1...V-type engine, 1A, 1B...bank,
2...Cylinder block, _C1 to _C6 ...Cylinder, 3,
4...Cylinder head, 6...Intake manifold, 8...Intake port, 10, 11...Independent intake passage, 10a, 11a...Surge tank side passage,
10b, 11b...Intake port side passage, 12...
Surge tank, 13, 14... Upper and lower surge tanks, 13a, 14a... Introductory passage section, 15... Partition wall, F... Connection surface, 16, 17... Connection flange section, 18, 19... Mounting bolt, 36...Injector, 37...Fuel supply pipe, 38...
Bonnet.

Claims (1)

[Scope of utility model registration request] In an intake system for a V-type engine, which includes two banks each having a plurality of cylinders, and in which the intake ports of each cylinder are formed inside both banks so as to face each other, each independent intake passage connected to the intake port is The independent intake passages are assembled in a surge tank disposed above one bank, and each of the independent intake passages has a substantially horizontal connecting flange, and the independent intake passages are lined up in the connecting flange at a predetermined interval between cylinders. A portion of the independent intake passages immediately upstream of the connection flange portion is formed in a curved manner, and a gap is provided between the independent intake passages that is wider than the connection interval at the connection flange portion, and in this gap, the connection flange portion An intake system for a V-type engine, characterized in that a mounting bolt is arranged to fasten one side portion of the V-type engine.