JPH0366498B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a double intake port type intake system for an internal combustion engine, in which one of the intake ports is a pure helical port and the other is a partially helical port. The present invention provides a device that can simplify the port shape and valve mechanism, maintain high volumetric efficiency, and improve swirl characteristics at the same time.

<Prior Art> The basic structure of a double intake port type intake system for an internal combustion engine is described, for example, as shown in Fig. 1.
The two intake ports 2 and 3 for one cylinder chamber 1 of the internal combustion engine E are connected to the axis S of the camshaft 5 of the valve train 4.
are formed in the cylinder head 6 in parallel in the direction A parallel to the intake ports 2 and 3, and both port inlets 7,
8 are opened on the same side surface 10 of the cylinder head 6, and both port outlets 11 and 12 are opened on the end face 14 of the cylinder chamber.

Generally, a double intake port type intake device is adopted when it is desired to increase the amount of intake air, but as shown in Japanese Patent Publication No. 52-7485, the conventional technology of this type is a double intake port type intake device with the above basic structure. One side is formed as a direct port and the other as a helical port, and the outlet of the direct port is deviated from the center of the cylinder chamber to the side perpendicular to the port inlet side, and the outlet of the helical port is formed as a port rather than the center of the cylinder chamber. There is one in which the helical port is deviated toward the inlet side, the helical port is formed in a crank-bent shape, and the lengths of both ports are set to be approximately the same distance.

<Problems to be Solved by the Invention> However, in the above conventional technology, since the distances from the axis of the camshaft to each intake port are greatly different from each other, a bridge body is interposed between both intake valves and the rocker arm. , and a linear guide mechanism for the bridge body must be provided, making the valve train complicated and large.

Furthermore, since the helical port is bent in a crank shape, the intake resistance becomes large, which weakens the swirl, and also reduces the dynamic effect and lowers the volumetric efficiency.

Moreover, helical ports have a complicated shape and are difficult to manufacture. Furthermore, in the double intake port system, the cross-sectional area is increased in order to increase the amount of intake air, so the intake speed decreases.

For this reason, if a double intake port is applied to a small displacement diesel engine that requires a relatively strong swirl with a small vortex, the swirl will become weaker due to the reduction in intake speed, and the appropriate swirl will be reduced. Characteristics cannot be obtained.

The technical object of the present invention is to solve the above problems.

<Means for Solving the Problems> Means for achieving the above-mentioned problems will be explained below using FIGS. 1 to 9, which correspond to embodiments.

That is, based on the direction B in which the intake air swirl to be generated in the cylinder chamber 1 flows between the parallel portions 15 of both port outlets 11 and 12, the intake port 2 located on the windward side is used as the direct direction of the intake air flow. The intake port 3 located on the leeward side is formed in the shape of a partial helical port that makes use of a part of the direct component of the intake flow, and both port exits 11, 12 are arranged side by side in a direction parallel to the camshaft axis S at positions offset from the cylinder chamber center C toward the port inlets 7 and 8.

<Effects of the Invention> The present invention has the following effects because it is configured as described above.

(a) Since the intake port is of a double type and the cross-sectional area can be increased, the intake resistance does not become extremely large even during high-speed operation, and the amount of intake air can be increased.

(b) Since the distance from the axis of the camshaft to the outlet of each intake port is equal to each other, whether the intake valves of both intake ports are driven directly by the intake cam of the camshaft or via the rocker arm,
The intake cam or rocker arm and the intake valve can be directly interlocked, there is no need to interpose a bridge body, and a linear guide mechanism for the bridge body can also be omitted, so the valve operating system can be simplified.

C. The intake port on the leeward side has a partial helical port shape, and part of the intake air becomes a swirling flow, so it can generate a stronger swirl than a direct port.

In addition, both port outlets are lined up parallel to the axis of the camshaft, and the distance from the side surface of the head that opens at both port inlets to the above outlet is not extremely short compared to the other, which prevents air flow. The upper helical port is approximately the same length as the partial helical port on the leeward side.
As a result, the intake port can be formed into a gently curved shape, reducing the intake resistance and increasing the swirl.

As a result, as mentioned above, although the amount of intake air can be increased with a general double intake port,
This is disadvantageous for downsizing the engine because the intake speed decreases and the swirl weakens, whereas the double intake port type intake system of the present invention provides a strong swirl even in the case of a small displacement engine. Therefore, the mixing performance of fuel and air can be improved, and the air utilization rate can be improved.

Furthermore, since the mixing performance of fuel and air can be improved, exhaust gas can be purified and fuel efficiency can be improved.

D. The leeward side intake port is connected tangentially to the swirl flow in the cylinder chamber and is formed as a partial helical port, so a part of the intake air taken in from this port becomes a direct component and flows into the cylinder. Air flows forcefully in the tangential direction along the inner wall with little intake resistance.

As a result, while a strong swirl can be obtained as described above, the volumetric efficiency can be made higher than in the case of forming a pure helical port.

Furthermore, since the private helical port is formed in a gently curved shape, volumetric efficiency can be maintained at a high level.

This allows you to increase the amount of intake air from both helical ports, and as mentioned above, make the swirl stronger and improve the air utilization rate.
The torque and output of the engine can be increased, and the performance of the engine can be improved.

Since the helical port can be formed into a gently curved shape, it can be made into a much simpler shape than the conventional example mentioned above, and can be manufactured easily.

<Example> Hereinafter, an example of the present invention will be described based on the drawings.

Figure 1 is a cross-sectional plan view of the main part of the cylinder head, Figure 2
The figure is a vertical side view of the main parts of a vertical diesel engine.
FIG. 3 is a plan view of the main part of the cylinder head,
Vertical diesel engine E has cylinder block 1
6 is provided with a plurality of cylinder chambers 1 at predetermined intervals, and a piston 17 is provided in each cylinder chamber 1 so as to be movable up and down.
Insert.

The valve drive camshafts 5 and 65 of the intake system and the exhaust system are mounted before and after each cylinder chamber 1, and the valve drive camshafts 5 are connected to the intake valve drive device 4 via the advance device 18, and
The valve train camshafts 65 are respectively linked to the exhaust valve train 60.

Reference numeral 19 denotes a common transmission shaft passing through the cylinder block 16 from side to side, which controls an advance device 18 and an intake path device switching valve 21 that opens and closes a short-circuit path 20 connected to one of the intake ports, for example, a partially helical port to be described later. It is something that is driven.

The cylinder head 6 is mounted on the cylinder block 16.
are mounted and fixed, two intake ports 2 and 3 and an exhaust port 22 are arranged in the parts of the cylinder head 6 corresponding to each cylinder chamber 1, and a unit injector mounting hole 24 is arranged in the center C of the cylinder chamber 1. Further, glow plug mounting holes 25 are formed from the center C toward the exhaust port 22, respectively.

The intake ports 2 and 3 are formed in the cylinder head 6 in parallel in the direction A parallel to the valve drive camshaft 5, and both port inlets 7 and 8 are opened on the same front side surface 10 of the cylinder head 6. The port outlets 11 and 12 are located side by side in a direction parallel to the cam axis S at a position that is offset from the cylinder chamber center C toward the port inlets 7 and 8.

Then, with reference to the direction B in which the intake swirl to be generated in the cylinder chamber 1 flows between the parallel portions 15 of both port outlets 11 and 12, the intake port 2 located on the windward side is connected to the pure helical port. In addition, the intake port 3 located on the leeward side
are respectively formed into partial helical ports.

Of the above-mentioned double intake ports, the upwind pure helical port 2 has the periphery of the port outlet 11 raised high in a cylindrical shape as shown in FIGS. The direct component is killed at the port outlet 11, and the air is blown approximately radially into the cylinder chamber 1 along the cylindrical inner wall 11a to generate a swirl (see FIG. 8).

As shown in FIGS. 6 and 7, the partially helical port 3 on the leeward side has a portion 12a of the port outlet 12 raised up in a cylindrical shape, and the other portion 12b.
is formed vertically so as to be able to blow through from the inlet 8 to the outlet 12 of the port in a substantially vertical direction, so that part of the intake air flows directly into the cylinder chamber 1 from the longitudinally elongated portion 12b, and the remaining intake air flows through the cylindrical inner wall 12.
Swirl is generated along line a (see Figure 8).

On the other hand, the exhaust port 22 has its port outlet 26
are opened at the rear side 27 of the cylinder head 6, and the port inlets 28 and 29 are branched into two, and the port outlet 2 is opened from the center C of the cylinder chamber.
6 side, and position them side by side in a direction parallel to the valve train cam axis S of the exhaust system.

The above-mentioned intake valve train 4 is composed of a tappet 30, a push rod 31, and a rocker arm 32, and the cylinder block 1 is located above the valve train camshaft 5.
6 and the cylinder head 6, a push rod insertion hole 33 is made at a corresponding location.

Then, loosely fit the push rod 31 into this,
The lower end 34 of the push rod 31 is brought into contact with the advance device 18 via the tappet 30 which is similarly fitted into the push rod insertion hole 33 so as to be vertically movable.

Note that the valve train 60 of the exhaust system is also configured in the same manner.

In addition, two rocker arm shafts 37 and 38 are mounted on the front and rear sides of the upper wall 35 of the cylinder head 6 via a plurality of brackets 36, respectively, and a bifurcated intake rocker arm 3 is attached to the front rocker arm shaft 37.
2, and a bifurcated exhaust rocker arm 39 is swingably supported on the rear rocker arm shaft 38 for each cylinder chamber 1.

At low speeds, the driven arm 3 is controlled by hydraulic pressure.
2b is configured to disengage from the driving arm 32a and rest the private helical port.

Two intake valves 40, 41 are provided for each cylinder chamber 1 between the front and rear rocker arm shafts 37, 38.
and two exhaust valves 43 and 45 are arranged to be able to move up and down, with lower ends 46 of the intake valves 40 and 41 facing the intake port outlets 11 and 12, and upper ends 47 of the intake valves 40 and 41 facing the two output ends of the intake rocker arm 32. 48,66
make it come into contact with

At this time, the intake valve 40 facing the private helical port 2 has the output end 66, and the intake valve 41 facing the partial helical port 3 has the output end 4.
8 are in contact with each other.

The lower ends 50 of the exhaust valves 43, 45 face the exhaust port inlets 28, 29, and the upper ends 51 of the exhaust valves 43, 45 face the two output ends 52 of the exhaust rocker arm 39,
53.

In addition, the intake rocker arm 32 is connected to the clutch mechanism 6.
2, the driving arm 32a and the driven arm 32b
is engaged, and the output end 48 is connected to the main drive arm 32a.
Further, an output end 66 is formed on the driven arm 32b.

At low speeds, the driven arm 32b is disengaged from the driving arm 32a by the hydraulic system, and the driving arm 32a causes the intake valve 41 facing the partially helical port 3 to operate in one direction.

Therefore, the private helical port is suspended and
Since the intake air is concentrated in the partial helical port, the swirl can be made stronger.

Reference numeral 54 denotes a unit injector that is fitted into the unit injector insertion hole 24 and is located approximately in the center of the intake/exhaust ports. Reference numeral 55 represents a glow plug that is inserted into the glow plug insertion hole 25 and is located at the exhaust port 22. placed close to each other.

Reference numeral 56 denotes a valve closing spring that biases the intake/exhaust valves to close.

Upper end 31a of the push rod 31 of the intake system
is in contact with the input end 63 of the intake rocker arm 32, and the two intake valves 4 are rotated by the rotation of the valve drive camshaft 5.
0 and 41 are driven to open and close.

In this case, the rocker arm shaft 37 of the intake system, the valve train camshaft 5, the two outlets 11 of the intake ports 2 and 3,
12 are arranged parallel to each other, the lengths of the arms of the bifurcated intake rocker arm 32 can be made equal, and the pressing force of the rocker arm 32 on the two intake valves 40, 41 can be made equal.

Note that this also applies to the exhaust system.

Therefore, the function of this double intake port will be explained using Fig. 9.
In this case, it is possible to generate a swirl with a substantially uniform strength from the center C of the cylinder chamber 1 to the cylinder wall, while in the partially helical port, since a part of the direct component remains, the swirl near the cylinder wall near the port, That is, it can be seen that the swirl strength can be increased as the eccentricity value approaches a region where the value takes a large negative value.

Therefore, the functions exhibited by both helical ports act synergistically to generate a strong swirl within the cylinder.

In addition, the present invention can simplify the valve mechanism by setting the two intake port outlets parallel to the valve drive cam axis, so this simplification can be applied not only to single-cylinder engines but also as the number of cylinders in an internal combustion engine increases. The effect will be greater.

Furthermore, although the present invention assumes a double intake system, the exhaust system may have one or more exhaust systems.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a cross-sectional plan view of the main part of a cylinder head, FIG. 2 is a longitudinal cross-sectional side view of the main part of a vertical diesel engine, and FIG. 3 is a plan view of the main part of the cylinder head. Figure 4 is a longitudinal sectional front view of the private helical port, and Figure 5 is the − of Figure 4.
6 is a vertical sectional front view of the partially helical port, FIG. 7 is a sectional view taken along the line - - of FIG. 6, FIG. 8 is a schematic diagram showing the intake flow of the double intake port, and FIG. 9 1 is a relationship diagram showing eccentricity and swirl strength in a cylinder chamber at an intake port outlet. 1... Cylinder chamber, 2, 3... Intake port, 4
... Valve gear, 5... Camshaft of 4, 6... Cylinder head, 7, 8... Inlet of intake port, 10...
...lateral side of 6, 11, 12...exit of intake port, 14...end face of cylinder chamber, 15...11 and 1
Between parallel parts of 2, E... internal combustion engine, S... axis of 5, A... direction parallel to S, B... direction of swirl.

Claims (1)

[Claims] 1 For one cylinder chamber 1 of the internal combustion engine E, two intake ports 2 and 3 are formed in the cylinder head 6 in parallel in the direction A parallel to the axis S of the camshaft 5 of the valve train 4, and both A double intake port type for an internal combustion engine, in which both port inlets 7, 8 of intake ports 2, 3 are opened on the same side surface 10 of the cylinder head 6, and both port outlets 11, 12 are opened on the cylinder chamber end face 14. In the intake system, with reference to the direction B in which the swirl of intake air to be generated in the cylinder chamber 1 flows between the parallel portions 15 of both port outlets 11 and 12, the intake port 2 located on the windward side is used as an intake air flow. At the same time, the intake port 3 located on the leeward side is formed in the shape of a partial helical port that makes use of a part of the direct component of the intake flow, and both port exits are 11 and 12 are arranged side by side in a direction parallel to the camshaft axis S at positions offset from the cylinder chamber center C toward the port entrances 7 and 8. Intake device.