JPH0147607B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an intake system for a V-type engine, and particularly to an intake system in which a primary intake passage and a secondary intake passage are formed independently.

(Prior art) In an engine intake system, in order to provide good intake air to each cylinder, the intake inertia effect is effectively utilized by synchronizing the pulsation of the intake passage and the number of intake operations of the cylinder, and the filling efficiency is improved. For example, there is a method shown in Japanese Utility Model Publication No. 48-34401. This is done by providing a surge tank (air chamber) in the intake passage, supplying intake air to each cylinder through an independent passage from this surge tank, and eliminating interference with the intake inertia effect due to intake air interference between cylinders. The surge tank installed in the middle of the intake passage is divided into two, and cylinders with different firing orders are connected to each divided chamber.

In addition, the engine's intake passage is divided into a primary intake passage and a secondary intake passage, and when the amount of intake air is small in a low load range, intake air is supplied only from the primary intake passage, thereby increasing the flow velocity and improving combustibility. However, an intake system for an engine is known in which when the amount of intake air is large, intake air is also supplied from secondary intake air to improve output. In order to apply this device to a V-type engine and improve the intake inertia effect by installing the surge tank described above, the two intake ports should have different characteristics to reduce torque drop at both low and high speeds. It is desirable to prevent crowding. This objective is achieved by making one length of the intake pipe longer and the other shorter, but in this case, in a V-type engine with many restrictions on placement, it is necessary to create a configuration that does not increase the size of the device. need to be adopted.

Furthermore, in order to flatten the structure and shape of a V-type engine, Japanese Patent Publication No. 51-42272 proposes placing the intake manifold in a V-shaped chamber; The purpose is to avoid contamination of the intake manifold and the intake pipe system branching from the intake manifold.

(Object of the Invention) This invention was made against this technical background, and uses the above-mentioned surge tank in the intake system of a V-type engine to exert an intake inertia effect and to improve the intake system at high and low speeds. In either case, there is no drop in torque,
Furthermore, the present invention provides an intake device that is relatively compact.

(Structure of the Invention) This invention has a plurality of cylinders arranged at a predetermined angle inclination to the left and right, and each cylinder has a first intake port that opens in the entire operating range of the engine, and a first intake port that opens in a specific operating range of the engine. In a V-type engine equipped with two intake ports, a first surge tank is provided in the space between the left and right cylinder rows,
A second surge tank is provided on both sides of the first surge tank, and a first surge tank is provided in each cylinder.
One of the second intake ports is connected to the first surge tank, and the other intake port is connected to the second surge tank. In this configuration, when connecting the first surge tank to the first intake port, the first intake passage is set short and the second intake passage is set long, and the first surge tank is connected to the second intake port. When connecting to the intake port of
The first intake port is made longer and the second intake port is made shorter.

(Example) In FIGS. 1 to 3, in a V-type six-cylinder engine 1, each cylinder 2 is inclined left and right at a predetermined angle and is arranged symmetrically with respect to a center line 10. The cylinder head 3 of the engine 1 has a first intake port 4 that supplies intake air during low loads and high loads, and a second intake port 5 that supplies intake air during high loads, each opening into a combustion chamber 6. It is provided. A first intake valve 41 and a second intake valve 51 are arranged at the openings of the intake ports 4 and 5, respectively. Further, an exhaust port 61 opens in the combustion chamber 6, and an exhaust valve 62 is disposed at the opening. 31 is a fuel injector, which is provided at the first intake port 4 to promote atomization of fuel.

The second intake port 5 and exhaust port 61 are opened and closed by a valve train. That is, the cam 55
The rocker arms 53 and 63 are swung by the rotation of the rocker arms 53 and 63, and the second intake valve 51 and the exhaust valve 62 are connected to the spring 5 at the other end of the rocker arms 53 and 63, respectively.
7, by pushing down against the force of 58, the second
The intake port 5 and the exhaust port 61 are opened. The rocker arm 53 swings about a hydraulic pivot 54, and when the load is low, the hydraulic pivot 54 moves back and forth by the cam 34 to increase or decrease the amount by which the other end of the rocker arm 53 presses the second intake valve 51. The intake port 5 of the valve is activated or deactivated, and the clearance is automatically adjusted when the valve is activated.

Also, due to the rotation of the cam 55, the locking arm 5
9 is also swung about the pivot 56, and opens and closes the first intake port 4 by pushing down the first intake valve 41 against the force of the spring 42.
The pivot 56 presses down the rocker arm 59 with hydraulic pressure so that the clearance of the first intake valve 41 is automatically adjusted.

An exhaust passage 66 is connected to the exhaust port 61,
Further, the first intake port 4 has a first intake passage 70.
However, the second intake port 5 has a second intake passage 81.
are connected to each other. A first surge tank 7 is arranged in the space between the left and right cylinder rows,
The first intake passage 70 is connected to this, and a second surge tank 8 is arranged on both sides of the first surge tank 7, and a second intake passage 81 is connected to this. . Therefore, the first intake passage 70 is formed short, and the second intake passage 81 is formed long, and the length of the second intake passage 81 is such that the intake pulsation and the number of intake operations are synchronized and the intake inertia effect is achieved. The length is set so that it occurs. The upstream intake passage 9 includes a third intake passage 71 and a fourth intake passage 82.
The third intake passage 71 is connected to the first surge tank 7, and the fourth intake passage 82 is connected to the second surge tank 7.
is connected to the surge tank 8. Reference numeral 91 indicates a dividing line, and the intake system is divided into a pair of blocks including the second surge tank 8, the first surge tank 7, and the third intake passage 71. This allows for easy assembly and disassembly. As shown in FIG. 3, the second intake passage 81 branched from the second surge tank 8 is led to three cylinders each on the left and right, and the cylinder rows on each side are cylinders whose ignition order is not consecutive. divided into groups.

In the above configuration, since the first surge tank 7 is arranged in the space between the left and right cylinder rows, the space is effectively used and the entire device is configured compactly, and one of the intake passages is shortened. , it is convenient to form the other long.

In this configuration, the second intake port 5 is closed when the load is low, and intake air is supplied from the first surge tank 7 to the combustion chamber 6 through the first intake passage 70 and the first intake port 4. Since this passage is formed short, the intake resistance is small, and therefore the flow velocity of the intake air is high, and swirl is effectively generated within the combustion chamber to promote combustion. On the other hand, when the load is high, the second intake port 5 is also opened and the second surge tank 8 is also connected to the second intake passage 8.
1. Intake air is supplied through the second intake port 5, and sufficient intake air is supplied to the combustion chamber 6. Furthermore, since the second intake passage 81 is formed long, the intake air filling efficiency is increased due to the intake inertia effect. Therefore, there is no drop in torque either under low load or high load, and well-balanced torque characteristics can be obtained.

Note that the arrangement of the first surge tank and the second surge tank may be reversed so that the first intake passage is set long and the second intake passage is set short. In this case, the intake inertia is reduced at low load. This effect improves intake air filling efficiency and provides well-balanced torque characteristics as a whole.

(Effects of the Invention) As explained above, the present invention provides a surge tank in a V-type engine to improve charging efficiency through the intake inertia effect, and utilizes the space between the left and right cylinder rows. This makes the configuration more compact.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention;
FIG. 2 is a cross-sectional view taken along the - line, and FIG. 3 is a plan view of FIG. 1. DESCRIPTION OF SYMBOLS 1... Engine, 2... Cylinder, 4... First intake port, 5... Second intake port, 6... Combustion chamber, 7
...first surge tank, 8...second surge tank, 70...first intake passage, 81...second intake passage.

Claims (1)

[Claims] 1 A plurality of cylinders are arranged horizontally and inclined at a predetermined angle, and each cylinder is provided with a first intake port that opens in all operating ranges of the engine and a second intake port that opens in a specific operating range of the engine. In the V-type engine, a first surge tank is provided in the space between the left and right cylinder rows, a second surge tank is provided on both sides of the first surge tank, and the first and second surge tanks are provided in the space between the left and right cylinder rows. An intake system for a V-type engine, wherein one of the intake ports is connected to the first surge tank, and the other intake port is connected to the second surge tank.