JPH079184B2 - Engine intake system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of an intake system for an engine, which utilizes the dynamic effect of intake air to improve output.

(Prior Art) Conventionally, as an air intake device of an engine, for example, Japanese Patent Laid-Open No. 59-708
As disclosed in Japanese Patent No. 33, 33, the intake passages of each cylinder of a two-cylinder rotary piston engine are communicated with each other at a communication portion downstream of a throttle valve, and intake ports of both cylinders formed by the communication passage and an intake passage downstream thereof By appropriately setting the communication length between the cylinders, the closing compression wave and the opening compression wave generated in the intake passage at the time of closing and opening the intake port of one cylinder, respectively, are transmitted to the entire cylinder of the other cylinder through the above communication portion. It is known that supercharging is performed by propagating to an intake port immediately before closing and obtaining a dynamic effect due to intake interference between cylinders.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional one, since the communication length between the intake ports of both cylinders formed by the communication passage and the intake passage downstream thereof is constant, a dynamic effect is obtained. Can only be obtained in a specific rotation range according to this communication length.

Therefore, a control valve that collects the intake passages upstream of the throttle valve and communicates with the communication passage downstream of the throttle valve and that opens at high engine speed is provided in the communication passage, and the control valve is closed at low engine speed. The communication length between the intake ports of both cylinders is made long by the collecting portion and the intake passages downstream thereof, while the control valve is opened at high engine speed to open the communication length between the intake ports of both cylinders. It is conceivable that the dynamic effect can be effectively obtained in the entire engine rotation range by making the length short by the communication passage and the intake passage downstream thereof.

However, in this case, the opening and closing of the control valve is switched at the engine speed corresponding to the intersection of the torque characteristic curve when the control valve is normally open and the torque characteristic curve when the control valve is normally closed, so that the torque connection is smooth. Will be
The opening / closing switching point of the control valve and the intersection point of the torque characteristic curve do not always exactly match due to the operating state of the engine or variations in each engine, and in that case, there is a problem that a torque shock occurs when switching the control valve. .

By the way, as an intake device of the engine, a low load intake port and a high load intake port are provided in each cylinder, and the first intake passage is connected to the low load intake port of each cylinder of the cylinder group, and each cylinder of the cylinder group is connected. A second intake passage is connected to a high-load intake port of a cylinder to change the opening degree of each intake passage according to the load to appropriately set the flow rate and flow velocity of the air-fuel mixture supplied to each cylinder. It has been known.

In order to obtain the above-mentioned dynamic effect in the entire rotation range in such an intake device, the communication length between the first intake passages and the communication length between the second intake passages between the cylinder groups are shortened. In order to do so, a first intake passage communication passage and a second intake passage communication passage that short-circuit the first intake passage and the second intake passage, respectively, are provided, and the communication of the respective communication passages is controlled by the control valve according to the engine speed. It is conceivable that the communication length of each intake passage is changed by opening and closing.

The present invention has been made in view of the above point, and an object thereof is to provide an engine having intake passages for low load and high load for each cylinder group, as described above, for each load. The purpose of the present invention is to reduce the torque shock by gradually changing the torque characteristics by providing a time difference between the open / close switching of the communication of the communication passage provided for each intake passage.

(Means for Solving the Problems) In order to achieve the above-mentioned object, a solution means of the present invention is a first intake passage connected to a low load intake port of each cylinder of a cylinder group, and each cylinder of the cylinder group. Of the second intake passage connected to the high-load intake port, and the communication length between the first intake passages between the cylinder groups and the communication length between the second intake passages are shortened to propagate pressure between the cylinder groups. To open and close the first intake passage communication passage and the second intake passage communication passage, which are short-circuited between the first intake passage and the second intake passage, to open and close the first intake passage communication passage. A first control valve and a second control valve that opens and closes the second intake passageway are provided, and the first control valve and the second control valve are opened and the first control valve is opened at least during high engine rotation and high load. And the operation timing of the second control valve is shifted. .

(Operation) With the above configuration, in the present invention, when the first control valve and the second control valve are closed at the time of low engine speed, the communication length between the load intake ports of both cylinder groups is substantially the entire length of each intake passage. It becomes a long one, and the low-frequency dynamic effect matching the engine speed can be satisfactorily obtained.

On the other hand, when the first control valve and the second control valve are opened at high engine speed and high load, the communication length between the load intake ports of both cylinder groups is short formed by the communication passage and the intake passage downstream thereof. Therefore, the high-frequency dynamic effect matching the engine speed can be satisfactorily obtained.

In addition, during transition between low engine speed and high engine load and high engine speed, the operation timings of the first control valve and the second control valve are deviated so that the first intake passage and the second intake passage communicate with each other. Since the lengths are switched with a time lag, the torque characteristic is changed in two stages due to the change in the dynamic effect, and the torque shock is reduced.

(Example) Hereinafter, the Example of this invention is described based on drawing.

1 to 3 show an embodiment in which the present invention is applied to a two-cylinder rotary piston engine. This engine has a centrally located intermediate housing 1
And front and rear rotor housings 2a, 2b arranged on both sides of the intermediate housing 1 and having trochoidal inner peripheral surfaces, and front and rear side housings arranged before and after each rotor housing 2a, 2b. 3
a and 3b, and two cylinders C, C are formed inside thereof by these housings. A polygonal rotor 4 is arranged in each cylinder C, each rotor 4 is supported by an eccentric shaft 5, and each rotor 4 makes a planetary rotational motion to form a partition in each cylinder C. The three working chambers 6, 6, 6 to be operated are made to sequentially perform the intake, compression, explosion, expansion and exhaust strokes.

Further, the intermediate housing 1 has primary ports (low-load intake ports) 7 and 7 that supply fresh air to the working chambers 6 of the cylinders C in the entire operating range. Further, a secondary main port (higher than the primary main port 7 of each of the side housings 3a, 3b) that supplies fresh air to the working chamber 6 of each cylinder C only when the engine is under a high load is provided on the leading side in the rotor rotation direction. The secondary auxiliary port for supplying fresh air to the working chamber 6 of each cylinder C at the time of high engine high load at the rotor rotation direction leading side of each secondary main port 8 is opened. Port 9 is open.

Further, each primary port 7 has a first intake passage 10
Are connected, and the first intake passages 10, 10 of the cylinder C are assembled on the upstream side thereof and connected to the air cleaner 11. A second intake passage 12 is connected to each of the secondary main port 8 and the secondary auxiliary port 9, and the second intake passages 12, 12 of the cylinder C are assembled at their upstream ends and connected to the air cleaner 11. . At the downstream end of the second intake passage 12, the secondary auxiliary port 9 of the second intake passage 12 is provided.
A valve 14 for opening and closing the communication with the valve 14 is provided, and the valve 14 is driven by a diaphragm type actuator 15 having an intake negative pressure as an operation source, and the actuator 15 is controlled by a controller 16. The controller 16 includes throttle valves 17a to 17a provided in the intake passages 10 and 12, respectively.
The opening degree of c, the signal of the air flow sensor 18 and the engine speed signal are input, and while the valve 14 is opened when the engine is running at high speed and high load, the valve is opened in other operating ranges.
It controls to close 14.

Further, in the middle of the first intake passages 10, 10, the first intake passages are communicated with each other, and the communication length of the first intake passages 10, 10 is made shorter than the communication length through the confluence portion. There is provided a first intake passage communication passage 19 for short-circuiting the first intake passages so as to obtain a dynamic effect by the pressure propagation between the cylinders. further,
In the middle of the second intake passages 12 and 12, the second intake passages are communicated with each other, and the communication length of the second intake passages 12 and 12 is made shorter than the communication length through the confluent portion. Second short circuit between the second intake passages to obtain a dynamic effect by the pressure propagation of the second
A communication passage 10 for the intake passage is provided.

A first control valve 21 that opens and closes the communication passage 19 is provided in the first intake passage communication passage 19, and a second control valve that opens and closes the communication passage 20 in the second intake passage communication passage 20. 22 are provided. The first control valve 21 and the second control valve 22 are both cylindrical rotary valves, and are individually driven by diaphragm type actuators 23 and 24 which use intake negative pressure as an operation source. The actuators 23 and 24 open the first and second control valves 21 and 22 at the time of high engine speed and high load by the controller 16 while closing both control valves 21 and 22 in the other operating range and The control timings of the first control valve 21 and the second control valve 22 are controlled so as to be earlier than the control timing of the second control valve 22. Incidentally, 25 is an injector arranged in each intake passage 10, 12, and 26 is an ignition plug arranged in each rotor housing 2a, 2b.

Therefore, in the above embodiment, when the engine speed is low, the first control valve 21 and the second control valve 22 are closed, and the passage length between the primary ports of both cylinders C, C is determined by the first intake passage 1
The length of the passage between the secondary main ports of both cylinders C and C is the second as well as the length is almost zero.
Since the intake passage 12 has a long length formed by almost the entire length, a low-frequency dynamic effect matching the engine speed can be favorably obtained.

On the other hand, when the engine speed is high and the load is high, the first control valve 21 and the second control valve 22 are opened, and the passage length between the primary ports of both cylinders C, C is set to the first intake passage communicating passage 19 and the downstream thereof. And the length of the passage between the secondary main ports of both cylinders C, C is defined by the second intake passage communicating passage 20 and the second intake passage 12 downstream thereof. Since the length is shorter, the high frequency dynamic effect matching the engine speed can be satisfactorily obtained.

Further, during transition between low engine speed and high engine load and high engine speed, the operation timings of the first control valve 21 and the second control valve 22 are deviated so that the first intake passage 10 and the second intake passage 12 are separated from each other. Since the communication length of the intake passage is switched with a time difference, the torque characteristic is changed in two stages due to the change of the dynamic effect, and the torque shock is reduced.

Moreover, in that case, since the operation timing of the first control valve 21 is earlier than the operation timing of the second control valve 22, the first control valve 21 has a smaller intake flow rate.
Since the dynamic effect on the intake passage side is changed first, the torque characteristic can be changed smoothly.

Furthermore, FIG. 5 shows a modification of the present invention. It is intended that the engine intake system of the present invention is applied to a reciprocating engine of the series six-cylinder, divided into cylinder groups _{C 1 ~C 3, C 4 ~C} 6 of each cylinder C ₁ -C ₆ intake stroke not continuous , Each cylinder group C ₁ ~ C ₃ , C ₄
First intake passage for low load intake ports 7 'of each cylinder -C ₆
10 ', and the second intake passage 12' is connected to the high load intake port 8'to reduce the communication length between the first intake passages and the communication length between the second intake passages between the cylinder groups. A first intake passage communication passage 19 'and a second intake passage communication passage 20' that short-circuit the first intake passage and the second intake passage to obtain a dynamic effect by pressure propagation between the cylinder groups. A first control valve 21 'and a second control valve 2 are provided in the communication passages 19' and 20 ', respectively.
2'is provided to open the first control valve 21 'and the second control valve 22' at least at the time of high engine speed and high load, and to shift the operation timing of the first control valve 21 'and the second control valve 22'. In addition to the same operation as the above embodiment,
Cylinder groups C _{1 to} C ₃ and C ₄ that do not have consecutive intake strokes in each cylinder C _{1 to} C ₆
-C can be prevented decay of the pressure wave of each cylinder C ₁ -C ₆ and efficient pressure propagation in all engine speeds to obtain good dynamic effect made by dividing the _6.

(Effects of the Invention) As described above, according to the engine intake system of the present invention, the communication length between the first intake passages connected to the low-load intake ports of each cylinder of the cylinder group and the cylinder group. The communication length between the second intake passages connected to the high-load intake ports of each cylinder is shortened according to the engine speed and the load, and the communication lengths between the intake passages are switched with a time lag. As a result, efficient pressure transmission is achieved in the entire engine speed range, and a dynamic effect can be obtained satisfactorily while reducing the torque shock when switching the communication length between the intake passages.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is an overall schematic configuration diagram, FIG. 2 is a side view of an engine, and FIG. 3 is a plan view of the engine. Further, FIG. 4 is an overall schematic configuration diagram in a modified example of the present invention. 7 ... Primary port, 8 ... Secondary main port, 9 ... Secondary auxiliary port, 10,10 '... First intake passage, 12,12' ... Second intake passage, 19,19 '... First Intake passage communication passage, 20,20 '... Second intake passage communication passage, 21,21' ... First control valve, 22,22 '... Second control valve,
C ... cylinder.

Claims (1)

[Claims] 1. A first intake passage connected to a low load intake port of each cylinder of a cylinder group, a second intake passage connected to a high load intake port of each cylinder of a cylinder group, and the cylinder group. Between the first intake passages and the second intake passages so that the communication length between the first intake passages and the communication length between the second intake passages are shortened to obtain a dynamic effect due to pressure propagation between the cylinder groups. A first intake passage communication passage and a second intake passage communication passage that are respectively short-circuited, a first control valve that opens and closes the first intake passage communication passage, and a second control that opens and closes the second intake passage communication passage. An engine including a valve and opening the first control valve and the second control valve at least when the engine is rotating at a high speed and a high load and shifting the operation timings of the first control valve and the second control valve. Intake device.