JPS6129962Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake manifold for an internal combustion engine in which a blocking wall having a cutout groove at the lower end is provided in an offset manner so that a substantially uniform concentration of air-fuel mixture can be distributed to three cylinders.

When feeding air-fuel mixture to three cylinders lined up in a straight line using one carburetor, if each cylinder and carburetor are connected to each other with the shortest pipe line, each pipe length should be the same. Therefore, the distribution of the air-fuel mixture supplied to each cylinder becomes uneven, causing fluctuations in the air-fuel ratio. In addition, when the vaporizer is a so-called horizontal type vaporizer having a horizontal inner hole, and the main jet is of a type that projects horizontally from one side wall of the air hole, the air is sucked and discharged from the main jet. As illustrated in FIG. 5, the fuel f tends to deviate toward the facing wall d, which is opposite to the wall c from which the main jet b projects, due to velocity energy, inertia, etc. during discharge.
As a result of the air-fuel mixture in which the high concentration portion h is unevenly distributed on the side closer to the wall surface d flowing into the intake air introduction portion e of the intake manifold a, this together with the difference in pipe length,
Even greater non-uniformity occurred in the air-fuel ratio of the air-fuel mixture fed to each cylinder g. One solution to this problem is, for example, to extend the length of the pipe by providing a curved part in the central pipe, making the length of the entire pipe approximately uniform. , central dividing wall i that divides the air-fuel mixture into left and right halves
By providing partition walls j and j extending to the vicinity of the dividing wall i, the air-fuel mixture is uniformly dispersed and the flow of the air-fuel mixture in the lower layer is prevented even in the low speed range, thereby improving the distribution of the air-fuel mixture. Utility Model Publication No. 51-39057 proposes a method that aims to equalize the concentration of air, but all of these methods are suitable for cases in which the air-fuel mixture, in which high concentration portions are already unevenly distributed, flows into the intake manifold's intake introduction section. Therefore, it is extremely difficult to equalize the air-fuel ratio, and it is therefore impossible to solve problems such as variations in output from cylinder to cylinder due to non-uniform air-fuel ratios.

The object of the present invention is to provide an intake manifold for an internal combustion engine (hereinafter referred to as "intake manifold") that can solve the above problems and can deliver a substantially uniform air-fuel mixture in both high and low speed ranges. One embodiment of the invention will be described below with reference to the drawings.

The figure shows an embodiment of the intake manifold 1 of the present invention, in which first to third cylinders 6, 7, and 8 are arranged in a straight line. The carburetor 3 is of a so-called horizontal type in which the air hole 10 having the constriction part 9 is installed horizontally, and the constriction part 9 has a main jet 11 horizontally protruding from one wall surface 12 and has an opening in the center. There is also an idle port 1 near the throttle valve 14 on the downstream side.
5 is drilled into the upper wall surface 16, for example.

The intake manifold 1 has an intake introduction part 17 that communicates with the outlet of the carburetor 3, and a central part that communicates with the intermediate second cylinder 7 via a branch part 19 that is shaped like a right-angled isosceles triangle and widens toward the downstream side. The branch pipe part 20 and the two branch pipe parts 21 and 22 on both sides leading to the first and third cylinders 6 and 8 are branched and communicated symmetrically and horizontally, and the branch pipe parts 20 and 2
The tip portions of 1 and 22 are bent downward, and the ends thereof are connected by a mounting plate 24. Note that the mounting plate 24 is attached to the first and third cylinders 6,
It can be closely attached and fixed to the inclined wall surface of the internal combustion engine 2 which is provided with the air-fuel mixture intake ports 23 that communicate with the air-fuel mixtures 7 and 8, respectively.
- The third cylinders 6, 7, 8 are branch pipe parts 20, 2
It can conduct with 1 and 22. A blocking wall 2 is provided at the branching part 19.
6 is provided. The blocking wall 26 includes the branch pipe portion 20,
21 and 22, for example, at a position approximately halfway between the intake introduction part 17 and the inlet of the branch pipe parts 20, 21, 22, the blocking wall 26 extends in a direction across the branch part 19, and the blocking wall 26 11 protrudes from the wall surface 18 side facing the wall surface 12, therefore, the third
For example, at the lower end of the blocking wall 26 on the side of the branch pipe 21, a relatively long notch 27 is formed that extends through its front and rear surfaces. Note that the blocking plate 26 has a length l that is approximately the same as the inner diameter D of the branch pipe portions 20, 21, and 22, and the center of the blocking wall 26 is about 5 to 30% of the length l. In the example, about 10% of the branch pipe portion 22
On the other hand, the notch groove 27 is set to have a length that is more than half the length l of the blocking wall 26. Note that the length of the notched groove 27 may be determined experimentally to determine the optimum value for each internal combustion engine. Furthermore, in this example, the intake manifold 1 has a preheating water channel 30 which is an opening provided on the front surface of the mounting plate 24 and which communicates with the water jacket 31 of the internal combustion engine 2 and also with the hole 32 located approximately in the center of the branch part 19. It is formed.

However, in the intake manifold 1,
The fuel f sucked and atomized from the main jet 11 protruding from the wall surface 12 of the horizontally placed carburetor 3 is as follows:
The high-concentration portion h drifts toward the other wall surface 18 and is sucked into the intake manifold 1 from the intake introduction portion 17, collides with the barrier wall 26, further promotes vaporization, and the barrier wall 26 , wall 1
8 side, that is, toward the branch pipe portion 22 side, the high concentration portion h is efficiently diverted to flow down through the left and right edges 26a and 26b of the blocking wall 26. As a result, the intake manifold 1 can be filled with a homogenized air-fuel mixture.
- The air-fuel ratio of the air-fuel mixture flowing into the third cylinders 6, 7, and 8 can be maintained substantially uniform. Furthermore, in the low-speed rotation range where the opening degree of the throttle valve 14 is small, the air flowing down from the idle port 15 and at a low speed is not sufficiently atomized and the intake air introduction part 1
7, the fuel that flows in as a so-called wall flow along the wall surface passes through the cutout groove 27 at the lower end of the barrier wall 26 and flows into the branch pipe portions 20, 21. Equal amounts of fuel can be supplied to cylinders 6, 7, and 8. Note that the wall flow varies depending on the wall condition, shape, and size of the carburetor 3 and the intake manifold 1, as well as the degree of rotation of the airflow, and therefore, the length and position of the notch groove 27 are determined as described above. It is optimally selected each time depending on the engine 2, carburetor 3, and intake manifold 1.

As mentioned above, the intake manifold of the present invention, when distributing air-fuel mixture from a horizontal carburetor to three cylinders, has a branch part that is offset to the side opposite to the wall surface from which the main jet of the carburetor protrudes. Since the barrier wall is formed with a cutout groove at the lower end, even if the air-fuel mixture flows from the main jet so that the other wall surface has a high concentration area, it will not collide with the air-fuel mixture. The air-fuel mixture can be divided to make the air-fuel mixture uniform. Therefore, the air-fuel mixture with an approximately equal air-fuel ratio can be sequentially supplied to each cylinder from each branch pipe, and the notched grooves allow the wall flow to pass through even at low speeds. It keeps the fuel ratio constant and allows the engine to run smoothly and efficiently.

The intake manifold of the present invention can be used for 6-cylinder, 9-cylinder internal combustion engines, etc., if the air-fuel mixture is supplied to 3 cylinders from one carburetor.
The carburetor can also be used in internal combustion engines that have cylinders that are multiples of the main jet. It can be suitably adopted for equalizing the uneven flow of fuel from. Furthermore, the barrier wall prevents the entire amount of air-fuel mixture from directly flowing into the central branch pipe section from the intake introduction section, and also abuts and divides the unevenly distributed high concentration section, and then flows from the edges on both sides. The length, shape, amount of eccentricity, etc. can be freely selected as long as the length, shape, amount of eccentricity, etc.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway plan view showing an embodiment of the present invention, Fig. 2 is a vertical sectional view thereof, Fig. 3 is a sectional view taken along line A-A in Fig. 1, and Fig. 4 is an installation view. FIG. 2 is an end view taken along the line B-B in FIG. 2 illustrating the plate, FIG. 5 is a line diagram illustrating drifting of the air-fuel mixture, and FIG. 6 is a sectional view illustrating a conventional intake manifold. 2... Internal combustion engine, 3... Carburetor, 6, 7, 8...
...Cylinder, 11...Main jet, 12...
Wall surface, 17...Intake introduction part, 19... Branch part, 2
0...Central branch pipe portion, 21, 22...Both branch pipe parts, 26...Block wall, 27...Notch groove.

Claims (1)

[Scope of utility model registration request] A central branch pipe part and two branch pipe parts on both sides are symmetrically and horizontally branched into the intake introduction part leading to a horizontally placed carburetor through a branch part that spreads into a roughly triangular shape, each leading to a cylinder. and a blocking wall extending laterally and located on the upstream side of the branch pipe portion is formed in the branch portion and is deviated oppositely to the wall surface from which the main jet of the carburetor projects; An intake manifold for an internal combustion engine, which has a cutout groove at the lower end that communicates with the front and rear.