JPH02277923A - Suction device of internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention A8 Object of the Invention (1) Industrial Field of Application The present invention relates to first and second intake valve ports which are provided in an engine body facing a combustion chamber and which are openable and closable. An intake valve is disposed in the engine body, first and second intake ports communicating with the first and second intake valve ports are provided in the engine body, and the second intake port communicates with the first and second intake valve ports.
The present invention relates to an intake system for an internal combustion engine in which a cutoff valve is disposed in an intake port so as to be openable and closable.

(2) Conventional technology Conventionally, such a device has been used, for example, in Japanese Patent Application Laid-Open No. 56-14601.
This method is known from Japanese Patent Application Laid-Open No. 59-43922 and the like.

(3) Problems to be Solved by the Invention By the way, in the above-mentioned conventional device, a cutoff valve is disposed in one of the two intake ports, and the cutoff valve is closed during low-speed engine operation to reduce the swirl effect in the combustion chamber. When the engine is operating at high speed, the shutoff valve is opened to improve charging efficiency. However, in such a device, high output is obtained when the engine is operated at low speed and when the engine is operated at high speed, and a drop in output torque is unavoidable when switching between low speed and high speed operation.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an intake system for an internal combustion engine that can avoid a drop in output torque through more detailed intake control according to the operating state of the engine. do.

B9 Structure of the Invention (1) Means for Solving the Problems According to the present invention, the first intake port is formed to generate a swirl in the combustion chamber when the shutoff valve is closed, and the first intake port is configured to generate a swirl at the first intake valve port. The first and second intake valves are connected to a valve driving means that can change the operating state between low speed operation and high speed operation of the engine, and a control device connected to the cutoff valve. The means switches the shutoff valve between a closed state and an open state when the valve drive means is in an operating state corresponding to low speed operation of the engine, and the valve drive means is in an operating state corresponding to high speed operation of the engine. The shutoff valve is configured to switch between a closed state and an open state at certain times.

(2) Effect According to the above configuration, four types of intake characteristics can be obtained by combining the operating state of the valve drive means of both intake valves and the open and closed states of the cutoff valve, and the It becomes possible to perform precise intake control.

(3) Example Hereinafter, an example of the present invention will be explained with reference to the drawings. First, in FIGS. 1 and 2, this vehicle-mounted D
In an OHC type multi-cylinder internal combustion engine, a plurality of cylinders 2 are arranged in series in a cylinder block 1, and the engine body E
A combustion chamber 5 is defined between a cylinder end 3 connected to the upper end of the cylinder block 1 to constitute a cylinder block 1, and a piston 4 slidably fitted into each cylinder 2.

Further, in the cylinder head 3, first and second intake valve lowers 6a6b and first and second exhaust valve lowers a and 7b are provided in a portion forming the ceiling surface of each combustion chamber 5. On the other hand, the cylinder head 3 is provided with first and second intake ports 8.9 which are opened at a common opening end on one side of the cylinder head 3, and the first intake port 8 is a mixture In order to guide the air to the first intake valve 6a while swirling, the second
The intake port 9 is substantially straight and connected to the second intake valve 6b. In addition, the first and second exhaust valve ports 7a and 7b are connected to substantially straight first and second exhaust ports 1.0.11, and both exhaust ports 10.11 are common to the other side of the cylinder head 3. Open to. Furthermore, a fuel injection valve FV is arranged at the confluence of the first and second intake ports 8.9.

A shutoff valve (2) that can be opened and closed is provided at the second intake port 9, and this shutoff valve (2) is driven to open and close by a drive motor M.

In the part of the cylinder head 3 corresponding to each cylinder 2,
First and second intake valves! 2a, 12b and the first and second exhaust valves 13a, 13b, two sets of guide tubes 14 are fitted and fixed, respectively, and the guide tubes 14... Valve springs 16 are contracted between the cylinder head 3 and flanges 15 provided at the upper ends of the intake valves 12a, 12b and the exhaust valves 13a, 13b, respectively, which protrude upward from the cylinder head 3. The intake valves 12a, 1 are connected by these valve springs 16...
2b and each exhaust valve 13a, 13b are biased upward, that is, in the valve closing direction.

Both intake valves 12a, 12b are connected to an intake valve side valve actuating means 19 whose operating state can be switched according to the operating state of the engine, and both exhaust valves 13a, 13b are connected to a valve operating means 19 whose operating state can be changed according to the operating state of the engine. Exhaust valve side valve drive means 20 that can switch the operating state
are concatenated.

Referring to FIGS. 3 and 4 together, the intake valve side valve drive means 19 is located 1/1/2 from the engine crankshaft (not shown).
A camshaft 21 that is rotationally driven with a reduction ratio of 2, a first cam 22 and a second cam 23 provided on the camshaft 21.
and a third cam 24, a rocker shaft 25 fixedly arranged parallel to the camshaft 21, a first driving rocker arm 26, a free rocker arm 27, a second driving rocker arm 28, and each rocker arm pivotally supported by the rocker shaft 25. 26, 27, and 28.

A first cam 22 is integrated into the camshaft 21 at a position corresponding to the first intake valve 12a, and a third cam 24 is integrated at a position corresponding to the second intake valve 12b. A second cam 23 is integrated in between. The first cam 22 has a base interior 22a and a high portion 22b that projects radially outward from the base interior 22a. Further, the second cam 23 has a shape suitable for high-speed operation of the engine, and has a shape that is suitable for high-speed operation of the engine, and has a shape that corresponds to the inside of the base 23a and the high part 2.
It has a higher portion 23b that protrudes from the inside of the base 23a with a larger protrusion amount and center angle range than 2b. Furthermore, the third cam 24 has a base interior 24a and a base interior 24a.
a, and a high part 24b protruding from the inside of the base 2.
4b has a protrusion amount and central angle range that are intermediate values between those of the high portions 22b and 23b. Then each cam 2
The valve opening characteristic curves of the high portions 22b to 24b of 2 to 24 are as shown in FIG. That is, in FIG. 5, the valve-opening characteristic curve by the first cam 22 is shown by 1, the valve-opening characteristic curve by the second cam 23 is shown by -, and the valve-opening characteristic curve by the third cam 24 is shown by -.

On the other hand, the rocker shaft 25 is fixedly held in the cylinder head 3 at a position below the camshaft 21 and has an axis parallel to the camshaft 21 . The rocker shaft 25 includes a first drive rocker arm 26 that is interlocked and connected to the first intake valve 12a, a second drive rocker arm 28 that is interlocked and connected to the second intake valve 12b, and first and second drive rocker arms. Free rocker arms 27 arranged between 26 and 28 are respectively pivoted adjacent to each other.

The first and second drive rocker arms 26.28 have tabs 7
) The screws 31 are screwed together so that they can move forward and backward, and these tappet screws 31 connect the corresponding intake valves 12a and 12b.
touches the top edge of the Therefore, both intake valves 12a, 12b
will operate in response to the rocking movement of the redrive rocker arm 26,28.

The free rocker arm 27 is resiliently biased in the direction of sliding contact with the high-speed cam 23 by resilient biasing means 30 (see FIG. 1) interposed between the cylinder and the rad 3.

The hydraulic connection switching mechanism 29 connects the first drive rocker arm 26
and a first switching pin 32 that can connect the free rocker arm 27, a second switching pin 33 that can connect the free rocker arm 27 and the second drive rocker arm 28, and a movement of the first and second switching pins 32 and 33. It is provided with a regulation bin 34 for regulation, and a return spring 35 for urging each of the bins 32 to 34 toward the disconnection side.

The first drive rocker arm 26 includes a free rocker arm 27.
A first guide hole 36 with a bottom and open to the side is bored parallel to the rocker shaft 25, and the first guide hole 36 is formed in a cylindrical shape.
The switching pin 32 is slidably fitted into the first guide hole 36, and a hydraulic chamber 37 is defined between one end of the first switching pin 32 and the closed end of the first guide hole 36. Furthermore, the first drive rocker arm 26 is provided with a passage 38 communicating with a hydraulic chamber 37, and the rocker shaft 25 is provided with an oil supply passage 39. The oil supply passage 39 always communicates with the hydraulic chamber 37 via the passage 38 regardless of the swinging state of the first drive rocker arm 26. Furthermore, the oil supply path 39 is connected to a hydraulic pressure supply source 41 via a hydraulic control valve 40, and the hydraulic control valve 40 switches the hydraulic pressure from the hydraulic pressure supply source 41 between high and low levels to supply the oil supply path 39, that is, the hydraulic pressure chamber 37. Available.

A guide hole 42 corresponding to the first guide hole 36 is bored in the free rocker arm 27 in parallel with the rocker shaft 25 and extends between both sides, and one end is brought into contact with the other end of the first switching pin 32. The second switching bin 33 is connected to the guide hole 42
is slidably fitted to.

A bottomed second guide hole 43 corresponding to the guide hole 42 is provided in the free rocker arm 28 in the second drive rocker arm 28 .
A disc-shaped regulation bin 34, which is opened to the side and is bored parallel to the rocker shaft 25 and abuts the other end of the second switching bin 33, is slidably fitted into the second guide hole 43. A cylindrical guide member 44 is inserted and fixed at the closed end of the second guide hole 43, and a rod 45 that is movably inserted into the guide member 44 is provided coaxially and integrally with the regulating pin 34. . Therefore, the return spring 35 is inserted into the second guide hole 43.
The return spring 35 is compressed between the closed end of the return spring 35 and the regulating bin 34, and the bins 32, 33, and 34 that are in contact with each other are urged toward the hydraulic chamber 37 by the spring force of the return spring 35.

In this hydraulic connection switching mechanism 29, as the oil pressure in the hydraulic chamber 37 increases, the first switching pin 32 moves into the guide hole 4.
2, the second switching pin 33 is fitted into the second guide hole 43, and the rocker arms 26, 27, 28 are connected. Further, when the oil pressure in the hydraulic chamber 37 becomes low, the spring force of the return spring 35 causes the first switching pin 32 to move to the second switching pin 3.
3 returns to the position where the abutment surface with the first drive rocker arm 26 and the free rocker arm 27 corresponds, and the second switching bin 33 moves the abutment surface with the regulation bin 34 between the free rocker arm 27 and the second drive rocker arm 28. Since each rocker arm 26, 27, 28 is returned to the corresponding position, the connection state of each rocker arm 26, 27, 28 is released.

Therefore, in the intake valve side valve drive means 19, when the hydraulic connection switching mechanism 29 is in the disconnected state, the first intake valve 12a moves along the curve I in FIG. As shown, the second intake valve 12b opens and closes, and the second intake valve 12b opens and closes as shown.
The opening/closing operation is performed in a manner according to the shape of the cam 24 as shown by the curve (■) in FIG. Further, when the hydraulic connection switching mechanism 29 is in the connected state, the first and second intake valves 12a, 1
2b opens and closes in a manner that corresponds to the shape of the second cam 23, as shown by the curve {circle around (2)} in FIG.

By the way, the switching operation of the hydraulic control valve 40 and the opening/closing operation of the cutoff valve (2) are controlled by a control means C, and the control means C switches the hydraulic control valve 40, that is, the intake valve side, depending on the operating state of the engine. The valve drive means 19 and the shutoff valve V are controlled as shown in the following table.

The exhaust valve side valve drive means 20 basically has substantially the same configuration as the intake valve side valve drive means 19 described above.

Next, the operation of this embodiment will be described. When the engine is operated at low speed, the hydraulic pressure in the hydraulic chamber 37 in the hydraulic connection switching means 29 is kept at a low pressure by the hydraulic control valve 40. In this state, the intake valve side valve drive 19 operates as follows:
is opened and closed according to the shape of the first cam 22, and the second intake valve 12b is opened and closed according to the shape of the third cam 24. On the other hand, the shutoff valve V opens and closes as shown in the table above. That is, when the engine is running at a very low speed, the shutoff valve (2) is closed, and when the engine is running at a relatively high speed with the intake valve side valve actuating means 19 in an operating state corresponding to low speed operation, the shutoff valve (V) is opened.

Therefore, when the engine speed is extremely low, only the first intake port 8 is open, and the first intake valve 12 is in an open state.
When the valve a is opened, the air-fuel mixture is introduced into the combustion chamber 5 from the spiral-shaped first intake port 8 through the first intake valve 6a at a relatively high speed and while swirling. A powerful swirl occurs inside. Therefore, it is possible to improve combustibility in a lean state of fuel at extremely low speeds of the engine, and to reduce fuel consumption.

During low-speed engine operation, which has a large effect on fuel efficiency, the shutoff valve ■ can be changed in two stages between closed and open, allowing fine-grained changes in intake characteristics, contributing to improved intake efficiency. can do.

During high-speed operation of the engine, high oil pressure is applied to the hydraulic chamber 37 of the hydraulic connection switching means 29 by the hydraulic control valve 40, and each rocker arm 26, 27, 28 of the intake valve side valve actuating means 19 is
are integrally connected. As a result, both intake valves 12a, 12
b is opened and closed in a manner according to the shape of the second cam 23.

Moreover, in this state, the shutoff valve ■ is initially in the closed state,
Then, the valve becomes open. Therefore, the charging efficiency in the combustion chamber 5 can be improved by introducing the air-fuel mixture into the combustion chamber 5 at high speed only from the first-class port 8, and then introducing the air-fuel mixture into the combustion chamber 5 from both intake ports 8.9. By improving it, it is possible to achieve high rotation and high output.

In other words, if the intake valve opening characteristics are as shown in FIG. Direct switching causes a large change in the operation mode of the intake valve, and the flow rate does not increase, resulting in a decrease in filling efficiency. However, by closing the shutoff valve (1) once again when switching to the high-speed operating state, air is taken only from the first intake port 8, thereby increasing the intake flow rate and improving the filling efficiency.

In this way, by combining the change in the operating state of the intake side valve drive means 19 and the open and closed states of the shutoff valve (2), it is possible to obtain various intake characteristics depending on the operating state of the engine. This makes it possible to avoid a drop in output torque and achieve an increase in output.

C9 Effects of the Invention As described above, according to the present invention, the first intake port is formed to generate a swirl in the combustion chamber when the shutoff valve is closed, and the first and second intake valves have a A valve drive means that can change the operating state between operation and high-speed operation is connected,
The control means connected to the shutoff valve switches the shutoff valve between a closed state and an open state when the valve drive means is in an operating state corresponding to low speed operation of the engine, and when the valve drive means is in an operating state corresponding to low speed operation of the engine, and when the valve drive means is in an operating state corresponding to low speed operation of the engine. The shutoff valve is configured to switch between a closed state and an open state when in the operating state corresponding to the operation, so a total of 4 types of intake characteristics can be obtained and more precise intake control can be performed. In particular, it is possible to improve the swirl effect at very low speeds of the engine, and also to improve the filling effect at high speeds.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a vertical cross-sectional view of the main parts of an internal combustion engine, FIG. 2 is a view taken along the line ■-■ in FIG. 1, and FIG. FIG. 4 is a sectional view taken along the line IV--IV in FIG. 3, and FIG. 5 is a diagram showing the valve opening characteristics of each cam. 5... Combustion chamber, 6a... First intake valve port, 6b,
1. Second intake valve port, 8... First intake port, 9...
Second intake port, 12a...First intake valve, 12b...
・Second intake valve 19... Valve driving means, C... Control means, E... Engine body, ■... Shutoff valve Fig. 2

Claims (1)

[Claims] First and second intake valves are provided in the engine body facing the combustion chamber and can be opened and closed. In an intake system for an internal combustion engine, in which a second intake port is provided in the engine body, and a cutoff valve is disposed in the second intake port so as to be openable and closable, the first intake port is inserted into the combustion chamber when the cutoff valve is closed. The first and second intake valves are formed to generate a swirl and are connected to a valve driving means that can change the operating state between low speed and high speed operation of the engine, and a control means connected to the cutoff valve is connected to the first and second intake valves. , when the valve drive means is in an operating state corresponding to low speed operation of the engine, the shutoff valve is switched between a closed state and a valve open state, and when the valve drive means is in an operating state corresponding to high speed operation of the engine. An intake system for an internal combustion engine, characterized in that it is configured to switch a shutoff valve between a closed state and an open state.