JPH02277924A - 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 A2 Object of the Invention (1) Industrial Application Field The present invention provides a combustion chamber of one cylinder with first and second intake systems each connected to a combustion chamber of one cylinder, each of which can have different intake characteristics. This invention relates to an intake system for an internal combustion engine.

(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. 51-43922 and the like.

(3) Problems to be Solved by the Invention By the way, in the conventional device described above, a control valve is disposed in one of the two intake ports, and the control 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 control valve is opened to improve charging efficiency. However, in such a device, high output is obtained when the engine is operating at low speed and when operating 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 it is an object of the present invention 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. .

B1 Structure of the Invention (]) Means for Solving the Problems The present invention provides an intake system for an internal combustion engine in which a first and second intake system that can have mutually different intake characteristics are respectively connected to a combustion chamber of one cylinder. In the first intake system, the first intake system includes a first intake valve disposed to open and close a first intake valve port facing the combustion chamber, and a first intake port provided in the engine body connected to the first intake valve port. and a first control valve disposed at the first intake port to enable substantial intake stop, and the second intake system is disposed to open and close a second intake valve port facing the combustion chamber. Second
From the merging part between the intake valve and the first intake port and a second intake port provided in the engine body so as to be connected to the second intake valve port while merging with the first intake port on the upstream side of the first control valve. a second control valve disposed in the second intake port and capable of substantially stopping intake on the downstream side;
The intake valve is connected to a valve driving means that can switch between at least two operating states depending on the operating state of the engine, and a control valve that is connected to the first and second control valves to control the operation of the first and second control valves. The means includes a state in which the first control valve is opened and a second control valve is closed depending on the operating state of the engine;
A first feature is that the control valve is configured to be switchable between at least three states: a state in which the control valve is closed and the second control valve is opened, and a state in which both the first and second control valves are opened. shall be.

According to a second feature of the present invention, in addition to the configuration of the first feature, the control means controls the first control valve when the valve drive means is in an operating state corresponding to low-speed operation of the engine. The control valve is configured to switch between a state in which the first control valve is opened and the second control valve is closed, and a state in which the first control valve is closed and the second control valve is opened.

According to a third feature of the present invention, in addition to the configuration of the first feature, the control means controls the first control valve when the valve drive means is in an operating state corresponding to low speed operation of the engine. A state in which the second control valve is opened and the second control valve is closed, and a state in which the first and second control valves are closed.
A state in which both control valves are opened, and a state in which the first FF1LF control valve is closed and the second control valve is opened when the valve drive means is in an operating state corresponding to high-speed operation of the engine. and a state in which both the first and second control valves are opened.

Furthermore, the present invention provides an intake system for an internal combustion engine in which at least two first and second intake systems, which can have mutually different intake characteristics, are connected to a combustion chamber of one cylinder, in which the first and second intake systems include: The first intake system includes an intake valve disposed to respectively open and close at least two intake valve ports facing the combustion chamber, and an intake port provided in the engine body connected to each intake valve port, and the swirl generating means is a first intake system. At least the first control valve is disposed in the first control valve and is capable of substantially stopping intake.
Disposed in the intake port of the intake system, each intake valve is connected to a valve drive means that can switch between an operating state corresponding to low-speed engine operation and an operating state corresponding to high-speed engine operation, and controls the operation. A fourth feature is that the control means connected to the control valve is configured to sequentially switch between a valve open state, a valve closed state, and a valve open state in accordance with an increase in engine speed (2). Effect According to the configuration of the first feature, by combining the operating states of the first and second control valves and the operating states of the valve actuating means for both intake valves, the operation by the first and second intake systems is By increasing the number of combinations of intake characteristics, it is possible to perform more precise intake control.

Further, according to the configuration of the second feature, fine intake control can be performed in the low-speed engine operating state, which is a common range and has a large effect on fuel efficiency.

According to the configuration of the third feature described above, when the engine is running at extremely low speed, air is taken only from the first intake system to reduce fuel consumption, and at the beginning of high-speed operation of the engine, air is taken only from the second intake port for combustion. Intake efficiency can be improved by increasing the inflow speed into the chamber.

Further, according to the configuration of the fourth feature, the swirl effect can be enhanced by the swirl generating means during low speed operation of the engine, and an increase in intake resistance due to the swirl generating means can be suppressed by opening the control valve.

(3) Examples Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 show one embodiment of the present invention. First, in FIGS. 1 and 2, a plurality of cylinders are installed in a cylinder block 1 in a DOHC type multi-cylinder internal combustion engine mounted on a vehicle. 2 are arranged in series, and between a cylinder head 3 connected to the upper end of a cylinder block l to constitute an engine body E, and a piston 4 slidably fitted into each cylinder 2, there is a combustion engine. A respective chamber 5 is defined. The combustion chamber 5 of each cylinder has the first and second intake systems rsl, Is! are connected to each other, and the first and second exhaust systems ESS and ESz are connected to each other.

The first and second intake systems Is, , Is, have first and second intake valve ports 6a and 6b provided in the cylinder head 3 facing the ceiling surface of each combustion chamber 5, respectively, which can be opened and closed. 2 intake valves 12a, 12b and each intake valve port 6a, 6
first and second intake ports 8 and 9 that are continuous to cylinder head 3, and first and second intake ports 8;
, 9 respectively. In addition, the first and second exhaust systems ES, ,E
S is the cylinder head 3 facing the ceiling of each combustion chamber 5.
10. First and second exhaust valves 13a and 13b that can open and close the first and second exhaust valve lowers a and 7b, respectively, and first and second exhaust ports connected to both exhaust valve lowers a and 7b). 11.

The first intake port 8 is spirally bent to guide the air-fuel mixture to the first intake valve 6a while swirling.
The spiral itself constitutes a swirl generating means.

Further, the second intake port 9 is formed into a substantially straight line and continues to the second intake valve 6b. Moreover, the cross-sectional area of the first intake port 8 is set smaller than the cross-sectional area of the second intake port 9. Further, the first and second intake ports 8.9 are connected to the first and second intake ports 8.9.
They merge on the upstream side of the control valves V, V2, and open in common on one side of the cylinder head 3. Moreover, a fuel injection valve FV is disposed at the merging portion. Furthermore, the first and second
The exhaust ports 10.11 also merge on the downstream side and open in common on the other side of the cylinder head 3.

The first and second control valves V, , V are rotatable between a closed position where intake is substantially stopped and a fully open position, and are rotatably driven by drive motors Mt and Mz, respectively. Ru.

In the part corresponding to each cylinder 2 of the cylinder head 3,
In order to guide the first and second intake valves 12a, 12b and the first and second exhaust valves 13a, 13b, two pairs of guide tubes 14 are fitted and fixed, respectively. A valve spring 16 is provided between the cylinder head 3 and the flange portion 15 provided at the upper end of each intake valve 12a, 12b and each exhaust valve 13a, 13b that protrudes upward from the guide cylinder 14 of the cylinder head 3. ... are respectively contracted, and each intake valve 12a, 1 is compressed 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 FIG. 3 and Part 4, the intake valve side valve drive means 19 is located at 1/1/2 from the crankshaft (not shown) of the engine.
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. Further, the third cam 24 has a base interior 24a and a cough head interior 24.
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 cum 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 hent 3 at a position below the camshaft 21 and has an axis parallel to the camshaft 21 . The rocker shaft 25 includes a first driving rocker arm 26 that is interlocked and connected to the first intake valve 12a, a second driving rocker arm 28 that is interlocked and connected to the second intake valve +2b, and first and second driving rocker arms. Free rocker arms 27 arranged between 26 and 28 are respectively pivoted adjacent to each other.

Tappet screws 31 are screwed into the first and second drive rocker arms 26, 28 so that they can move forward and backward, and these tappet screws 31 connect the corresponding intake valves 12a, 12b.
touches the top edge of the Therefore, both intake valves 12a, 12b
will operate in response to the rocking motion of both drive rocker arms 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 free rocker arm 27 and the cylinder head 3.

The hydraulic connection switching mechanism 29 connects the first driving Ronca 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 the movement of the first and second switching pins 32 and 33. It is provided with a regulation pin 34 for regulation and a return spring 35 for urging each pin 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 bin 32 is slidably fitted into the first guide hole 36, and a hydraulic chamber 37 is defined between one end of the first switching bin 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 the hydraulic chamber 37, and the rocker shaft 25 is provided with an oil supply passage 39. The oil supply passage 39 is always in communication with the hydraulic chamber 37 via the passage 38 regardless of the swinging state of the first drive rocker arm 26. Moreover, the oil supply path 39 is connected to the oil pressure supply source 4I via the oil pressure control valve 40, and the oil pressure control valve 40 switches the oil pressure from the oil pressure supply #41 between high and low levels to the oil supply path 39, that is, the oil 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 pin 34, which is open to the side and is bored parallel to the opening/linker shaft 25 and comes into contact with the other end of the second switching bin 33, is slidably fitted into the second guide hole 43. .

A cylindrical guide member 44 is provided at the closed end of the second guide hole 43.
is inserted and fixed therein, and a rod 45 that is movably inserted into the guide member 44 is provided coaxially and integrally with the regulation bin 34 . The return spring 35 is then inserted into the second guide hole 4.
The pins 32, 33, 34 are compressed between the closed end of the return spring 35 and the regulating pin 34, and the pins 32, 33, 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 bin 32 is moved to 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 bin 32 to change to the second switching bin 3.
3 returns to the position where the contact surface with the first drive rocker arm 26 and the free rocker arm 2 corresponds, and the second switching bin 33 returns the contact surface with the regulation bin 34 to the free port 7 arm 27 and the second drive rocker arm. Since the rocker arms 26, 27, and 28 are returned to the corresponding position, the connection between the rocker arms 26, 27, and 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 according to the curve 1 in FIG. 5 in a manner corresponding to the shape of the first cam 22. The second intake valve L2b opens and closes as shown, and the second intake valve L2b 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 first and second intake systems TS, Is,
The operation of the control valves V, V, is controlled by a control means C, which controls the hydraulic control valve 40, that is, the intake valve side valve drive means 19, and the first and Second control valve V1. V2 is controlled as shown in Table 1.

The exhaust valve side valve drive means 20 shown in Table 1 has basically almost the same configuration as the intake valve side valve drive means 19 described above.

Next, the operation of this embodiment will be explained. When the engine is operated at low speed, the hydraulic pressure in the hydraulic chamber 37 in the hydraulic connection disconnection tA machine side 29 is kept at a low pressure by the hydraulic control valve 40. In this state, the intake valve side valve drive 19 is operated by the first intake valve 12.
A 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 first and second control valves V+, V
z opens and closes as shown in Table 1. That is, the first
A state in which the control valve 1 is open and the second control valve V2 is closed, a state in which the first control valve V is closed and the second control valve V2 is open, and the first and second control Valve V
+ and Vz are both open, which changes sequentially as the engine speed increases. Therefore, when the engine speed is extremely low, only the first intake port 8 is open, and when the first intake valve 12a is open, combustion flows from the first intake port 8 through the first intake valve 6a. The air-fuel mixture is introduced into the combustion chamber 5 at a relatively high speed and while swirling, and a strong swirl is generated within the combustion chamber 5. 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. Furthermore, during this very low speed operation, the spiral first intake port 8 is fully opened, thereby suppressing an increase in intake resistance as much as possible.

In addition, by switching to intake only from the second intake port 9, which has a substantially linear shape and whose cross-sectional area and valve operation mode are more suitable for high-speed ranges, intake efficiency can be increased while maintaining the intake flow rate.

Therefore, during low-speed engine operation, which has a large effect on fuel efficiency, by changing the combination of operating states of the first and second control valves V, V2 in three stages, the intake characteristics can be finely changed. It can contribute to improving efficiency.

During high-speed operation of the engine, high hydraulic pressure is applied to the hydraulic chamber 37 of the hydraulic connection switching mechanism 29 by the hydraulic control valve 40, and each rocker arm 26 of the intake valve side valve actuating means 19 is operated.
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.

In addition, the first and second control valves V, , V are also fully open, and the charging efficiency in the combustion chamber 5 is improved, making it possible to achieve high rotation and high output.

In this way, by combining the change in the operating state of the intake valve side valve drive means 19 and the change in the operating state of the first and second control valves V, V2, various types of intake air can be generated depending on the operating state of the engine. characteristics, and it is possible to avoid a drop in output torque and achieve an increase in output.

As a modification of the above embodiment, the hydraulic control valve 40, that is, the intake valve side valve actuating means 19, and the first and second control valves V, V2 may be controlled as shown in Table 2 below. .

Table 2 According to such control, it is possible to generate a swirl by intake air from only the first intake port 8 during extremely low speed operation of the engine, contributing to improving fuel efficiency, and the first and second control valves V .
(a and 12b may have the same valve opening timing and lift). At the beginning of high-speed operation of the engine, air is taken only from the second intake port 9, which is substantially straight, so that the air intake efficiency can be improved due to the high flow rate. Furthermore, in a higher speed operating range, by opening both control valves ① and ②2, air can be taken in from both ports 8.9 and the intake efficiency can be increased.

FIG. 6 shows another embodiment of the present invention, and parts corresponding to those in the above embodiment are given the same reference numerals.

The combustion chamber 5 includes a first intake system IS1' and a second intake system IS.
2 is connected to the combustion chamber 5, and the first intake system IS1' is connected to the combustion chamber 5.
A first intake valve 12a that can open and close a first intake valve 6a provided in the cylinder head 3 facing the ceiling surface of and a first control valve (1) disposed in the first intake port (8). Further, the second intake system IS2 is configured in the same manner as in the previous embodiment. Furthermore, both intake valves 12a, 12b are connected to intake valve side valve operating means 19 shown in FIGS. 1, 3, and 4.

The first control valves ■ and J are variable wings that together with the structure of the first intake port 8 constitute the swirl generating means 46. position O (the position shown by the broken line in FIG. 6) where the first intake port 8 should rotate toward the wall surface, and a half-open position M (the position shown in FIG. 6) where the mixture should be guided spirally to the first intake valve RO 6a (the position shown by the chain line) and the fully closed position S (the sixth position) where the first intake port 8 is fully closed.
The position shown by the solid line S in the figure) is rotated by a drive motor M1'.

The operations of the first and second control valves V, , V, and the intake valve side valve operating means 19 are controlled as shown in Table 3 below.

According to the example in Table 3, Table 2, when the engine speed is low, the first control valves V and I are kept half open, and the air-fuel mixture is spirally introduced into the combustion chamber 5 only from the first intake port 8. However, the swirl effect can be enhanced, and the air-fuel mixture can be introduced into the combustion chamber 5 only from the second intake port 9 at high speed in the early stages of engine high-speed operation, contributing to improvement in intake efficiency.

In Table 3, instead of closing the second control valve (2) when the engine is operating at low speed, the second intake valve 12b may be stopped.

C1 Effect of the Invention As described above, according to the first feature of the present invention, the operating states of the first and second control valves and the operating states of the valve drive means for both intake valves can be combined in a plurality of ways. Therefore, it is possible to obtain various intake characteristics by the first and second intake systems, and it is possible to perform more precise intake control.

According to the second feature of the present invention, it is possible to more finely change the intake characteristics in a low-speed engine operating state, and to perform fine intake control in a low-speed engine operating state that is in the normal use range and has a large effect on fuel efficiency.

Furthermore, according to the third feature of the present invention, it is possible to reduce fuel consumption by sucking air only from the first intake system when the engine is running at extremely low speeds, and at the same time, when the engine is running at a high speed, the second intake port Intake efficiency can be improved by taking air only from the air.

Furthermore, according to the fourth feature of the present invention, when the engine is operated at low speed, the swirl effect can be enhanced by the swirl generating means, and an increase in intake resistance can be suppressed by opening the control valve.

[Brief explanation of drawings]

1 to 5 show one embodiment of the present invention, in which FIG. 1 is a vertical cross-sectional view of a main part of an internal combustion engine, FIG. 2 is a view taken along the line ff-ff in FIG. 3 is a sectional view taken along the line mm in FIG. 1, FIG. 4 is a sectional view taken along the IV4/ line in FIG. FIG. 2 is a bottom view corresponding to FIG. 2 of the embodiment. 5... Combustion chamber, 6a... First intake valve port, 6b...
Second intake valve port, 8...first intake port, 9...second
Intake port, 12a... First intake valve, 12b... Second intake valve, 19... Valve drive means, 46... Swirl generation means, C... Control means, E... Engine Main body, I
S+, IS+... 1st intake system, IS2... 2nd intake system, V,, V... 1st control valve, V2... 2nd control valve Figure 3 Figure 5 Crank angle 4th Figure 6

Claims (4)

[Claims] (1) In an intake system for an internal combustion engine in which a first and second intake system that can have mutually different intake characteristics are respectively connected to a combustion chamber of one cylinder, the first intake system is connected to a first intake system facing the combustion chamber.
A first intake valve disposed to open and close the intake valve port, a first intake port provided in the engine body connected to the first intake valve port, and a first intake port that enables substantial intake stop. The second intake system includes a second intake valve arranged to open and close a second intake valve port facing the combustion chamber, and a second intake valve located upstream of the first control valve. The second intake port is provided in the engine body so as to be connected to the second intake valve port while merging with the first intake port at the second intake port, and the intake port is substantially stopped downstream of the merging part between the first intake port and the second intake port. a second control valve disposed in the second intake port, the first and second intake valves are connected to a valve drive means capable of switching between at least two operating states according to the operating state of the engine; A control means connected to the first and second control valves to control the operation of the first and second control valves opens the first control valve and closes the second control valve depending on the operating state of the engine. and a state in which the first control valve is closed and the second control valve is opened, and a state in which both the first and second control valves are opened. Features of internal combustion engine intake system. (2) The control means is configured to open the first control valve and close the second control valve when the valve drive means is in an operating state corresponding to low-speed operation of the engine; The intake system for an internal combustion engine according to item (1), wherein the intake system is configured to switch between closing the second control valve and opening the second control valve. (3) The control means is configured to open the first control valve and close the second control valve when the valve drive means is in an operating state corresponding to low-speed operation of the engine; A state in which the first control valve is closed and the second control valve is opened when the valve drive means is in an operating state corresponding to high-speed operation of the engine. The intake system for an internal combustion engine according to item (1), characterized in that it is configured to switch between a state in which both the first and second control valves are opened. (4) In an intake system for an internal combustion engine in which at least two first and second intake systems that can have mutually different intake characteristics are connected to a combustion chamber of one cylinder, the first and second intake systems are connected to a combustion chamber of one cylinder. The first intake system includes an intake valve arranged to open and close at least two intake valve ports facing the engine, and an intake port connected to each intake valve port and provided in the engine body, and the swirl generating means is arranged in the first intake system. A control valve capable of effectively stopping the intake is disposed at least at the intake port of the first intake system, and each intake valve has an operating state corresponding to low-speed operation of the engine and a control valve corresponding to high-speed operation of the engine. The control means, which is connected to a valve driving means that can switch between operating states, and is connected to the control valve to control the operation, switches between an open state, a closed state, and an open state according to an increase in engine speed. 1. An intake system for an internal combustion engine, characterized in that it is configured to sequentially switch between.