JP2716172B2 - Intake system for 4-cycle V-type multi-cylinder engine - Google Patents

Description

The present invention relates to an intake device for a four-cycle V-type multi-cylinder engine.

(Prior Art) In order to obtain the intake inertia effect over a wide speed range in this type of intake device, a long intake manifold effective in a low speed operation range and a short intake manifold effective in a high speed operation range are provided. Japanese Patent Application Laid-Open No. 62-20624 discloses an intake device that eliminates the torque valley (see the broken line in FIG. 5) that occurs in the medium speed operation range.

In the intake device, two adjacent manifolds among a plurality of primary manifolds are connected to each other through a communication path as a set, and these two intake manifolds are connected to cylinders having different suction timings, By providing a control valve that opens when the engine speed reaches or exceeds a specified value in the communication passage, the engine performance shown by the solid line in FIG. 5 is obtained, and the above-mentioned problem is solved.

(Problems to be solved by the invention) However, in the intake device according to the above proposal,
Since a plurality of control valves (that is, half the number of cylinders) are required, there is a problem that the structure is complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object the advantage that the engine output can be improved over the entire rotation speed range by simplifying the structure.
An object of the present invention is to provide an intake device for a cycle V-type multi-cylinder engine.

(Means for Solving the Problems) In order to achieve the above object, according to the present invention, a pair of cylinder rows formed by arranging a plurality of cylinders are arranged in a V-shape, and an intake manifold derived from an intake port of each cylinder is provided. It is composed of a primary manifold and a secondary manifold. The length of the primary manifold is set longer than that of the secondary manifold, and a secondary valve that opens in a high-speed operation range is provided in each secondary manifold. 4 cycle V with primary surge tank and secondary surge tank connecting manifold
In the intake device for a multi-cylinder engine, the primary surge tank is divided into two chambers, and the primary manifold is divided and connected to each of the two chambers. A single primary valve is provided to open the two chambers so as to communicate with each other, and the secondary manifold is connected to the secondary surge tank.

(Operation) In the present intake device, in the low-speed operation range, the primary valve and the secondary valve are both closed, so that the intake air flows through each of the two chambers and the primary manifold in the primary surge tank. At this time, the cylinder reaches the intake port of each cylinder. At this time, since the length of the primary manifold is long and the engine is adapted to a low-speed operation range where the engine speed is low, an effective pulsation effect and an intake inertia effect are obtained. The engine output is improved in the low-speed operation range.

Then, when the vehicle reaches the medium speed operation range, the primary valve provided in the primary surge tank is opened to connect the two chambers in the primary surge tank with each other, so that the primary surge tank is connected to the intake port of each cylinder. And the equivalent pipe length of the primary manifold is substantially shortened. For this reason, an effective intake inertia effect is obtained in the medium speed operation range. As a result, the engine output is improved even in the medium speed operation range, and the occurrence of a valley in the output is prevented.

In the high-speed operation range, the secondary valve provided in each secondary manifold is opened, so that the intake air reaches the intake port of each cylinder via both the primary manifold and the secondary manifold. In addition, an effective intake inertia effect can be obtained by the secondary manifold adapted to a high-speed operation range where the engine speed is short and the engine speed is high, and the engine output is improved even in this high-speed operation range.

Thus, according to the present intake device, it is possible to improve the engine output over the entire operating speed range. However, this effect is achieved by dividing the inside of the primary surge tank into two chambers. Since it is obtained by providing a single primary valve, the structure of the intake device can be simplified.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a four-cycle 6 equipped with an intake device according to the present invention.
FIG. 2 is a plan view of a front portion of a vehicle equipped with the engine, FIG. 3 is a plan view of an intake device according to the present invention, and FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. FIG. 5 is a diagram showing the performance characteristics of the engine.

First, a four-cycle six-cylinder engine 1 based on FIG.
In FIG. 1, reference numeral 2 denotes a crankcase, and a pair of cylinder rows is provided on the crankcase 2.
3, 3 are arranged in a V-shape. Each cylinder row 3 is formed by fitting a cylinder head 5 on a cylinder block 4, and three cylinders 6 are arranged in the cylinder block 4 in a direction perpendicular to the plane of FIG. And each cylinder 6
A piston 7 is slidably fitted therein, and the piston 7 is connected to a crankshaft 9 via a connecting rod 8.

An intake passage 10 and an exhaust passage 11 are formed at the position of each cylinder 6 in each cylinder head 5, and these are opened as an intake port 12 and an exhaust port 13 in the upper part of the combustion chamber S, respectively. The intake port 12 and the exhaust port 13 are opened and closed at appropriate timing by an intake valve 14 and an exhaust valve 15, respectively. The intake passage 10 is bifurcated and communicates with two intake ports 12 for each cylinder 6.

By the way, from the intake passage 10 formed for each cylinder 6 of each cylinder head 5, an intake manifold 16 which constitutes a part of the intake device according to the present invention is led out. Branch to cylinder row 3,
The primary manifold 16-1 that is thin and long and extends almost horizontally above 3 and is suitable for the low-speed operation range where the engine speed is low
And a secondary manifold 16-2 which is thick, short and suitable for a high-speed operation range where the engine speed is high. Note that a fuel injection valve 17 is mounted near the intake passage 10 of the intake manifold 16. An exhaust manifold (not shown) extends from the exhaust passage 11. Furthermore, each cylinder 6
A spark plug 18 is screwed onto the top of the plug. A high tension cord 19 derived from an ignition circuit (not shown) is connected to the spark plug 18. Thus, the engine 1
Is mounted in the direction shown in FIG. 1 and FIG. 2 on the vehicle with the right side being the front side.
As shown in FIG. 2, a total of six primary manifolds 16-1... Extend rearward (to the left in the figure) above 3, and the same number of secondary manifolds 16-2. Forward (in the figure,
(Right). The spark plug 18 provided for each cylinder 6 of the rear cylinder row 3
2 is disposed between two adjacent intake manifolds 16 and 16, as shown in FIG. 2, so that the ignition plug 18 can be easily replaced.

On the other hand, above the rear cylinder row 3, cylinders 6 ...
Of which the arrangement direction in the primary surge tank T ₁ smaller long capacity is provided, above the front cylinder bank 3 are secondary surge tank T ₂ is arranged large similar volume. The upstream ends of the primary surge tank T ₁ and the secondary surge tank T ₂ are assembled together via a bifurcated resonance pipe 20, and a throttle valve 21 is provided at the gathering portion (intake inlet) of the resonance pipe 20. Is provided. In addition, as shown in FIG. 2, the upstream end of the resonance tube 20 is connected to an air flow meter 22,
The air flow meter 22 is connected to an air cleaner via a suction pipe 23.
Connected to 24. In FIG. 2, reference numeral 25 denotes a radiator. And Thus, the intake device according to this embodiment, the primary manifold 16-1 ..., secondary manifold 16-2 ..., and the upper half of the primary surge tank T ₁ and the secondary surge tank T ₂ are formed integrally , The lower half divided by the dividing line A shown in FIG.

By the way, the primary surge tank T ₁ are divided into upper and lower chambers S _1, S ₂ by a partition wall 30 as shown in FIG. 4, these chambers S _1, the S ₂ the primary manifold 16−
1 ... are alternately connected, primary surge on an end portion of the tank T _1, a single, allowed to's eye through the chamber S ₁ and S ₂ are open at least medium speed velocity range primary valve V ₁ is provided. Further, the secondary surge tank T ₂ is connected the secondary manifold 16-2 ... all of, the connecting portion near to the secondary surge tank T ₂ of the in each secondary manifold 16-2 first As shown in the figure, the secondary valve V ₂ that opens in the high-speed operation range
Is provided. Incidentally, the primary valve V ₁ was opened and closed by an actuator 28 shown in Figure 3.

Meanwhile, the primary manifold 16-1 ... length and diameter of the by appropriately selected, and the primary surge tank T ₁ or the upper and lower chambers S _1, the capacity of the S ₂ to the equivalent to that of the secondary surge tank T ₂ Of course, it may be possible.

 Next, the operation of the intake device will be described.

In a low-speed operation range in which the engine speed N is lower than N ₁ (see FIG. 5), since the primary valve V ₁ and the secondary valves V ₂ are both closed, the intake air purified through the air cleaner 24. the suction pipe 23 is pulled to the negative pressure generated in the cylinder 6 ... in the air flow meter 22, the chamber S ₁ of the resonance tube 20, 1 primary surge tank T ₁ or S ₂ and the primary manifold 1
The air reaches the intake port 12 of each cylinder 6 via 6-1. In this case, since the length of the primary manifold 16-1 is long as described above, an effective intake inertia effect and a pulsating effect are obtained in this low-speed operation range, and as shown by a solid line in FIG. The engine output (torque) at (N <N ₁ ) is improved.

Then, the medium-speed operating range of the engine rotational speed N reaches N ₁ or more values further open the throttle valve 21 (N ₁ ≦ N <N
_2: In the first reference 5 Figure), but occupies passed,'s eye and the chamber S ₁ and S ₂ of the primary surge tank T ₁ and the primary valve V ₁ is opened as shown by chain lines in FIG. 4, the At times, an effective intake inertia effect is obtained by the long primary manifolds 16-1. That is, as described above, the chambers S ₁ and S ₂ are connected to each other, and as a result, the primary surge tank T ₁
, The equivalent pipe length of each primary manifold 16-1 is substantially reduced. Therefore, an effective intake inertia effect is obtained even in this medium speed operation range, and as shown by the solid line in FIG. 5, the medium speed operation range (N ₁ ≦ N <N ₂ )
As a result, the engine output can be improved, and a valley does not occur in the output unlike the related art.

Further, high-speed in the operating range (N> N _2), a secondary valve V ₂ provided on the secondary manifold 16-2 as described above the engine speed N is opened throttle valve 21 is further exceeds N ₂ Is open, the intake air is the primary manifold 16-1
And the secondary manifold 16-2, and reaches the intake port 12 of each cylinder 6. At this time, an effective intake inertia effect is obtained exclusively by the long secondary manifold 16-2. Also, the engine output is improved as shown by the solid line in FIG.

Thus, according to this air intake device, although the improvement of the engine output over the entire operating speed range can be achieved, this result divides the primary surge tank T ₁ into two chambers S _1, S _2, the 1 since obtained by providing a single primary valve V ₁ to the next surge tank T _1, it is possible to structure simplification of the intake system.

Furthermore, since in the present embodiment, arranging the secondary surge tank T ₂ a short secondary manifold 16-2 ... are lengths are connected to the upper row of cylinders 3 located on the front side of the vehicle, the secondary surge tank T ₂ does not protrude forward of the cylinder bank 3 on the front side, therefore, as shown in Figure 1 can be lowered position of the vehicle hood 27, it is possible to meet the requirements of the design.

In the above embodiment, the intake port of each cylinder 6
Since independent intake manifolds 16 were connected to the cylinders 12, respectively, the number of intake manifolds 16 equal to the number of cylinders was required, but the intake manifold 16 was connected to a pair of cylinders 6,
If they are commonly connected to the six intake ports 12, 12, only half the number of intake manifolds 16 is sufficient, and the structure of the intake device can be further simplified. Further, in the present embodiment, the intake manifold 16 is branched from the middle and the primary manifold 16 is branched.
-1 and the secondary manifold 16-2 are formed, but the primary manifold 16-1 and the secondary manifold 16-2 are made independent,
These may be connected to the combustion chamber S via the respective separate exhaust valves 14.

By the way, the example in which the present invention is applied particularly to the V-type six-cylinder engine has been described.
Needless to say, the present invention is applicable to a cylinder and other V-type multi-cylinder engines.

(Effects of the Invention) As is apparent from the above description, according to the present invention, the inside of the primary surge tank connected to the primary manifold adapted to the low-speed operation range is divided into two chambers, and By providing a single primary valve that opens in the middle or higher speed range, the effect that the engine output can be improved over the entire operating speed range can be obtained, so that the structure of the intake device can be simplified. Can be planned.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a four-cycle six-cylinder engine provided with an intake device according to the present invention, FIG. 2 is a plan view of a front portion of a vehicle equipped with the engine, and FIG. FIG. 4 is a plan view, FIG. 4 is a sectional view taken along line IV-IV of FIG. 3, and FIG. 5 is a performance characteristic diagram of the engine. 1 ... 4 cycle V type 6 cylinder engine, 3 ... cylinder line, 6 ... cylinder, 12 ... intake port, 16 ... intake manifold, 16-1 ... primary manifold, 16-2 ... secondary manifold, S _1, S ₂ ...... chamber, T ₁ ...... ₁ primary surge tank, T ₂ ...... ₂ primary surge tank, V ₁ ...... ₁ primary valve, V
₂ …… Secondary valve.

Claims (1)

(57) [Claims] A pair of cylinders each having a plurality of cylinders arranged side by side are arranged in a V-shape, and an intake manifold derived from an intake port of each cylinder is constituted by a primary manifold and a secondary manifold; The length of the manifold is set longer than that of the secondary manifold, and a secondary valve that opens in the high-speed operation range is provided in each secondary manifold, and the primary surge tank and the secondary surge tank that connect each manifold are installed. In the intake device for a four-cycle V-type multi-cylinder engine provided, the primary surge tank is divided into two chambers, and the primary manifold is divided and connected to each of the chambers. A single primary valve is provided that opens in the middle or higher speed range to allow the two chambers to communicate with each other, and connects the secondary manifold to the secondary surge tank. Intake system for a four-cycle V-type multi-cylinder engine according to claim.