JPS63120817A - Intake control device for engine - Google Patents

Abstract

PURPOSE:To improve torque in a wide operational region, by providing a means switching a condition of opening and closing an intake valve in accordance with the operational region, means changing the length of a low speed intake passage in accordance with the operational region and a means cutting off a high speed intake passage in the low speed operational region. CONSTITUTION:A tappet valve mechanism 2, which depresses an intake valve V1 downward to be opened, additionally provides a valve action change mechanism 6 which connects each rocker arm A1, when a pressure of working fluid is supplied through an oil path 5 in a rocker shaft 4, further enables each rocker arm A1 to perform the relative angular displacement when the pressure of working fluid is released. While a low speed intake passage, that is, an intake pipe part 15 of the first intake pipe 10 provides in its halfway a passage length change means for changing a length of the low speed intake passage by switching it to a condition that only an opening part 18 communicates with the first intake port P1 while to a condition that only an outflow port 16 communicates with the first intake port P1. And the passage length change means provides a selector valve 20 to be arranged in a position corresponding to the opening part 18.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Field of Application The present invention provides an intake valve in which a low-speed intake passage and a high-speed intake passage are connected to an intake valve port provided in an engine body. The present invention relates to an intake control device for an engine in which an intake valve that is driven to open and close by a valve mechanism is disposed at the mouth.

(2) Prior Art Conventionally, such devices have been disclosed in Japanese Patent Application Laid-Open No. 56-56499, for example.
It is known from the publication No.

(3) Problems to be solved by the invention In the conventional system described above, torque is improved by changing the number of intake valve operations, valve opening timing, and lift amount according to the operating state of the engine. ing.

By the way, during the intake stroke of a four-stroke engine, the air column in the intake passage is accelerated by the difference between the negative pressure generated in the cylinder and atmospheric pressure, and even if the piston passes the bottom dead center in the cylinder, the air column remains inertia. Therefore, it flows into the cylinder, and each time the static pressure in the head increases, the amount of filling into the cylinder increases. This is well known as the inertial effect of the intake passage, and when designing an engine, the intake valve should be adjusted to maximize the volumetric efficiency and hence the torque at a given engine speed. The valve opening timing and intake passage length are set, and conventionally, the length of the intake passage is determined in accordance with the high-speed operating range.

According to the above-mentioned inertial effect, by increasing the length of the intake passage corresponding to the intake valve that opens and closes in the low-speed operating range, it is possible to improve the torque in the low-speed operating range of the engine.

The present invention was made in view of the above circumstances, and improves torque over a wide range from low speed to high speed operation by changing the intake valve operation B and the intake passage length according to the engine operating condition. The object of the present invention is to provide an engine intake control device that achieves the following.

B0 Structure of the Invention (1) Means for Solving the Problems According to the present invention, the valve mechanism has a state in which the intake valve is opened and closed in an operating mode corresponding to a low-speed operating range, and a state in which the intake valve is driven to open and close in an operating mode corresponding to a low-speed operating range. A valve operation change means is provided that can switch between opening and closing the intake valve depending on the operation mode, and the low-speed intake passage has a
Passage length changing means is provided to change the length of the passage to be longer in a low-speed operating range and shorter in a high-speed operating range, and to cut off intake air in the low-speed operating range to the high-speed intake passage, which is formed short in response to the high-speed operating range. Intake blocking means are provided.

(2) Effect According to the above configuration, the length of the low-speed intake passage increases in the low-speed operating range of the engine, and the intake air from the high-speed intake passage is blocked, so that the torque in the low-speed operating range is improved. In addition, in the engine's high-speed operating range, the length of the low-speed intake passage is shortened and intake air starts from the shortened high-speed intake passage, which improves torque in the high-speed operating range. can.

(3) Example Hereinafter, an example of the present invention will be explained with reference to the drawings. First, in FIGS. 1 and 2, this engine is
This is a fuel injection type multi-cylinder engine, and the engine body 1 includes a first intake valve port H1 connected to a first intake valve port H1 for each cylinder CL.
A second intake port P2 connected to the second intake valve port H2 is provided, and a first intake valve 1 is provided in the first intake valve port H1, and is provided with a second intake valve 2 which also functions as an intake cutoff means.The engine body 1 is also provided with a pair of exhaust ports (not shown) for each cylinder CL. Exhaust valves are arranged corresponding to the exhaust ports, but each exhaust valve operates in the same way as the first and second intake valves Vl and V2, and only the engine intake system will be described in detail below. A detailed explanation of the exhaust system including the exhaust valve will be omitted.

Referring also to FIG. 3, the first and second
The intake valves Vl and V2 are spring-biased in the valve closing direction, that is, upward, and are opened by being pressed downward by the valve operating mechanism 2.

This valve mechanism 2 includes a low speed cam C1 and a high speed cam C3 that are integrally provided with a camshaft 3 that is rotationally driven at a reduction ratio of 1/2 according to the rotation of the engine, and a 1st, 2nd and 30th lever arms Al are swingably supported by a fixedly arranged rocker shaft 4;
, A2. A3, and a raised portion C2 is provided on the camshaft 3 between the two cams C1 and C2.

The low-speed cam C1 is integrally provided on the camshaft 3 at a position corresponding to the first intake valve v1, and the raised portion C2 is integrally provided on the camshaft 3 at a position corresponding to the second intake valve V2. Further, the high speed cam C3 is located between the low speed cam C1 and the raised portion 02, that is, the first and second intake valves Vl, V
The camshaft 3 is provided integrally with the camshaft 3 at a position corresponding to the gap between the camshaft 3 and the camshaft 3.

Moreover, the low-speed cam C1 has a high portion that protrudes outward in a relatively small amount along the radial direction of the camshaft 3, and the raised portion C2 is formed in a perfect circle concentric with the camshaft 3,
The high-speed cam C3 has a high portion in which the radially outward protrusion amount and center angle range of the camshaft 3 are larger than the high portion of the low-speed cam C1.

The first and 20th lever arms Al, A2 are basically formed in the same shape, and are swingably supported by the rocker shaft 4 so as to abut the upper ends of the first and second intake valves V1, V2. The 30th lever arm A3 is pivotally supported on the rocker shaft 4 between the first and 20th lever arms AI and A2. Moreover, the 30th hook arm A3 is urged upward by a spring (not shown) so as to constantly come into sliding contact with the high-speed cam C3.

When hydraulic pressure is supplied to such a valve mechanism 2 through an oil passage 5 provided in the rocker shaft 4, the first
- The 30th lever arms A1 to A3 are integrally connected, and when the hydraulic pressure is released, the 1st to 30th lever arms A1
A valve operation changing mechanism 6 configured to enable relative angular displacement of ~A3 is attached. When the first to 30th lever arms A1 to A3 are integrally connected by this valve operation changing mechanism 6, as the 30th lever arm A3 swings by the high-speed cam C3, the first and 20th lever arms AI, A2 swings, and the first and second intake valves Vl, V2
The opening and closing operations are performed at timing and lift amount depending on the shape of the high-speed cam 3. In addition, the valve operation changing mechanism 6 is
When the relative angular displacement of the 0-speed arms A1-A3 is allowed, the 10th
The lever arm A1 swings, and the first intake valve v1 opens and closes at a timing and lift amount depending on the shape of the low-speed cam C1. At this time, the 20th lever arm A2 remains in sliding contact with the raised portion C2 and does not swing, and the second intake valve 2 remains in its closed state.

In the middle of the pipe line 8 connecting the oil line 5 and the hydraulic pressure supply source 7,
An electromagnetic switching valve 9 is provided for switching between a state in which hydraulic pressure from the hydraulic pressure supply source 7 is supplied to the valve operation changing mechanism 6 and a state in which the hydraulic pressure in the valve operation changing mechanism 6 is released. This electromagnetic switching valve 9 has a state in which the hydraulic pressure of the valve operation changing mechanism 6 is released when the engine rotation speed is in a low-speed operation range below a predetermined first setting rotation speed N1, and a state in which the oil pressure of the valve operation changing mechanism 6 is released when the engine rotation speed is in a low-speed operation range below a predetermined first setting rotation speed N1. It is possible to switch between a state in which hydraulic pressure is supplied to the valve operation changing mechanism 6 when the engine is in a high-speed operation range exceeding the rotational speed N1.

Regarding the pair of exhaust valves of each cylinder CL, both intake valves Vl,
The same valve operating mechanism 2 and valve operation changing mechanism 6 related to V2 are provided.

Therefore, when the engine is in a low-speed operation range below the first set rotation speed N1, only the first intake valve ■1 and one exhaust valve open and close, and in a high-speed operation range exceeding the first set rotation speed N1, both intake valves Vl, V2 and re-exhaust valve are opened and closed. Moreover, the opening/closing timing and lift amount of the intake valves Vl and V2 and the exhaust valve are different between the low-speed operation range and the high-speed operation range, and the shapes of the low-speed cam C1 and the high-speed cam C3 that define the timing and lift amount are different for each operation. Each is set to improve torque in each region.

The first intake boat P of each cylinder CL in the engine body 1
I has a low-speed intake passage W working together with the intake boat P1.
A first intake pipe 10 for forming a high-speed intake passage WH is connected to the second intake port P2, and a second intake pipe 11 for forming a high-speed intake passage WH in cooperation with the intake port P2 is connected to the second intake pipe P2.
are connected to each other. Moreover, the first and second intake pipes 10.11 of each cylinder CL are commonly connected to an air chamber 12 that extends long along the cylinder arrangement direction of the engine body l.

A plurality of connection ports 13 are provided at the lower side of the air chamber 12 on the engine body 1 side, and a second connection port 13 corresponding to each cylinder CL is provided.
The intake pipes 11 are connected to connection ports 13, respectively. Further, the first intake pipe 10 is formed by interconnecting an intake pipe section 14 formed integrally with the second intake pipe 11 and an intake pipe section 15 integrally provided with the air chamber 12. One intake pipe section 15 connects the air chamber 12 from an outlet 16 opened on the side surface of the air chamber 12 opposite to the engine body 1.
A connection port 17 is located below the connection port 13 through the bottom of the intake pipe section 14, and the other intake pipe section 14 is connected to the connection port 17.

Referring also to FIG. 4, an opening 18 is provided at the bottom of the air chamber 12 so as to communicate with one of the intake pipe sections 15 midway. In the low speed intake passage WL,
The length from this opening 18 to the first intake boat P1 via the intake pipe section 14 is from the connection port 13 to the second intake pipe 1.
The length of the high-speed intake passage WH is set to be approximately the same as the length of the high-speed intake passage WH from 1 to 2nd intake bow) P2.

In the middle of the low-speed intake passage WL, that is, in the middle of the intake pipe section 15 in the first intake pipe 10, there are two types: one in which only the opening 18 is communicated with the first intake boat P1, and the other in which only the outlet 16 is communicated with the first intake boat P1. A passage length changing means 19 is provided for changing the length of the low-speed intake passage WL by switching between the communication state and the communication state. The passage length changing means 19 includes a switching valve 20 disposed at a position corresponding to the opening 18 in the middle of the suction pipe section 15, and an actuator 21 for driving the switching valve 20.

In FIG. 5, the switching valve 20 is constructed by connecting a plurality of valve bodies 22 arranged corresponding to each opening 18 with a common drive rod 23. The valve body 22 is constructed by connecting the edges of the -pair of discs 24 and 24 with a closure +yi25, and the closure plate 25.
The cross-sectional shape of is formed in a half-moon shape. Each valve body 22 is rotatably supported by arc-shaped support portions 27 formed on both upper and lower surfaces of the intake pipe portion 15 at a position corresponding to the opening 18, and the closing plate 26 supports the opening 18 as shown in FIG. When the valve body 22 is rotated 90 degrees from this state, the outlet 16 side of the intake pipe portion 15 can be closed.

The actuator 21 is, for example, a rotary solenoid, and a drive rod 23 is connected to the actuator 21 . Moreover, the actuator 21 operates to close the opening 18 with the valve body 22 when the engine speed is in a low-speed operating range below a second set speed N2 (for example, N2<Nl) different from the first set speed N1. However, in a high-speed operating range exceeding the second set rotational speed N2, the opening 18 is opened and the outlet 16 side is closed with the valve body 22, as shown in FIG.

Therefore, the length of the low-speed intake passage WL is a long distance from the outlet 16 to the first intake port P1 when the engine is in the low-speed operation range below the second set rotation speed N2, and the length of the low-speed intake passage WL is long from the outlet 16 to the first intake port P1. When entering a high-speed operation range exceeding the number N2, the length from the opening 18 to the first intake boat P1 becomes short and approximately the same length as the high-speed intake passage WH.

In the middle of the intake pipe portion 14 of each first intake pipe 10, a fuel injection valve ■F is disposed toward the first intake port PL,
from the fuel injection valve VF in accordance with the engine operating condition.
Fuel is injected into the intake boat Pl.

Next, the operation of this embodiment will be explained. First, when the engine is in a low speed operation range below the second set rotation speed N2, the length of the low speed intake passage WL is increased by the passage length changing means 19, so that the intake passage Torque improves due to increased inertia effect. Furthermore, when the engine is in a low-speed operating range below the first set rotation speed N1, which is different from the second set rotation speed N2, the valve operation changing mechanism 6 stops the operation of the second intake valve v2, and only the first intake valve v1 is operated. Opens and closes. At this time, the torque can be further improved by setting the opening/closing timing and lift amount of the first intake valve v1 to correspond to a low-speed operating range.

When the engine enters a high-speed operating range exceeding the second set rotation speed N2, the passage length changing means 19 shortens the length of the low-speed intake passage WL to approximately the same length as the high-speed intake passage WH. , its length is set to an appropriate length corresponding to the high-speed operating range, so it is possible to increase intake air filling efficiency and improve torque even in the high-speed range. Furthermore, when the engine enters a high-speed operating range exceeding the first set rotation speed N1,
The rocker arms A1 to A3 are connected by the valve operation changing mechanism 6, and the first and second intake valves Vl and V2 are both opened and closed at a timing and lift amount corresponding to the shape of the high-speed cam C3 to obtain high output. be able to.

Engine output P and torque T due to these effects
Fig. 7 shows the influence on the situation. In FIG. 7, AT, BT, and CT represent torque characteristics, and AP, BP, and CP represent output characteristics.

As is clear from Fig. 7, ζ for the output P is
The output characteristics are switched between the set rotation speed N2 and the first set rotation speed N1, and the output can be improved particularly in a high-speed operation range exceeding the first set rotation speed N1. Regarding torque T, the operating range is below the second set rotation speed N2, the operating range is above the second set rotation speed N2 and below the first set rotation speed N1,
and peaks in the operating range exceeding the first set rotational speed N1, thereby suppressing a drop in torque T as much as possible, and improving torque over a wide operating range from low-speed to high-speed operating ranges. .

In the above embodiment, the first set rotation speed Nl>the second set rotation speed N2, but the second set rotation speed N2>the first set rotation speed N1 may be satisfied. Furthermore, although the second intake valve (V2) is used as the intake valve V2, an intake valve (V2) may be provided separately from the second intake valve (V2).

C9 Effects of the Invention As described above, according to the present invention, the valve operating mechanism has a state in which the intake valve is opened and closed in an operating manner corresponding to a low-speed operating range, and a state in which the intake valve is opened and closed in an operating manner corresponding to a high-speed operating range. A valve operation changing means is provided that can change the driving state, and the low speed intake passage is provided with a passage length changing means that changes the length of the intake passage to be longer in the low speed driving range and shorter in the high speed driving range. The high-speed intake passage, which is formed short according to the engine speed range, is provided with an intake cutoff means that cuts off intake air in the low-speed operation range. Since intake air from the intake passage is blocked, torque in low-speed operating ranges can be improved.
Furthermore, in the high-speed operating range of the engine, the length of the low-speed intake passage is shortened and intake air starts from the shortened high-speed intake passage, which improves torque in the high-speed operating range. Torque can be improved over a wide operating range from low to high engine speeds.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a plan view of the main part, FIG. 2 is a sectional view taken along the line ■-■ of FIG. 1, and FIG. 3 is an enlarged view of FIG. 4 is a sectional view taken along the line IV-IV in FIG. 1, FIG. 5 is a perspective view of the switching valve, and FIG. 6 is a sectional view corresponding to FIG. 2 showing the state in which the passage length changing means is activated. 7 are engine output characteristic diagrams.

Claims (3)

[Claims] (1) An engine in which a low-speed intake passage and a high-speed intake passage are connected to an intake valve port provided in the engine body, and an intake valve that is driven to open and close by a valve mechanism is disposed at the intake valve port. In the intake control device, the valve mechanism includes a valve that can switch between opening and closing the intake valve in an operating mode corresponding to a low-speed operating range and opening and closing the intake valve in an operating mode corresponding to a high-speed operating range. An operation change means is provided, and the low speed intake passage is provided with a passage length change means for changing the length of the intake passage to be longer in a low speed operation range and shorter in a high speed operation range, and the length is shortened corresponding to the high speed operation range. An intake control device for an engine, characterized in that a high-speed intake passage is provided with an intake cutoff means for cutting off intake air in a low-speed operating range. (2) The first engine speed set to operate the valve operation changing means and the intake air cutoff means and the second engine speed set to activate the passage length changing means are set to be different from each other. An engine intake control device according to claim (1). (3) The engine body has a first air intake passage leading to the low speed intake passage.
A first intake valve is disposed to open and close the intake valve port, and a second intake valve is disposed to open and close the second intake valve port communicating with the high-speed intake passage. An engine intake control device according to claim 1 or 2, characterized in that: