JPS614821A - Intake device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve the idling stability of engine thus to improve the fuel consumption by arranging a throttle valve to be operated through an accelerator operating chip in the intake path trunk where a high speed intake path and a longer low speed intake path are connected in parallel at the upstream end. CONSTITUTION:An intake path trunk 7 is connected to the intake port 3 of an internal-combustion engine E while high speed intake path 8 and longer low speed intake path 9 are connected in parallel to the upstream end and the inlets of both intake paths 8, 9 are opened to common intake chamber 10. A gate valve 13 to be operated through an operating machine 15 is provided in the high speed intake path 8. While a throttle valve 12 to be operated through an accelerator operating chip 14 is provided in the intake path trunk 7. The intake path volume in the interval between an intake valve 5 and the throttle valve 12 can be set low without influenced by said paths 8, 9 through selection of the installing position of the throttle valve 12. Consequently, the idling of engine E can be stabilized.

Description

Detailed Description of the Invention A0 Objective of the Invention (1) Industrial Field of Application The present invention provides a high-speed intake passage at the upstream end of a main intake passage connected to an intake port of an internal combustion engine, and a high-speed intake passage that is longer than the high-speed intake passage. A long low-speed intake path is connected in parallel, an on-off valve is provided in the high-speed intake path, and the high-speed and low-speed intake paths are selectively operated by opening and closing the on-off valve according to the high and low speed operating conditions of the engine. The present invention relates to an intake system for an internal combustion engine, which constantly increases the filling efficiency of the engine through the intake inertia effect and produces high output.

(2) Prior art In this type of conventional intake system, each inlet of the high-speed and low-speed intake passages opens into a common intake chamber, and a throttle valve operated by an accelerator operator is provided in the inlet pipe of the intake chamber. ing.

(3) Problems to be Solved by the Invention In an intake system having such a configuration, since the distance from the intake valve of the engine to the throttle valve is long, the volume of the intake passage in that section becomes extremely large. The volume of the intake passage has a large effect on the stability of engine idling operation, and as the volume increases, idling operation tends to become unstable. Conventionally, as a countermeasure to this problem, the idle speed of the engine is set high, but this is not preferable in terms of fuel economy and quietness of the engine.

Therefore, the present invention installs the throttle valve at a specific location to increase the volume of the intake passage in the section from the intake valve to the throttle valve.

By making it possible to set it small without being affected by the low-speed intake passage, it improves the engine's idle link stability, and
An object of the present invention is to provide the above-mentioned intake device in which the high-speed and low-speed intake passages, etc. can be freely formed into shapes and dimensions desirable for high-output performance of the engine. Means The present invention is characterized in that a throttle valve operated by an accelerator operator is interposed in the main intake passage.

(2) Effect According to the above configuration, the throttle valve stripes are provided in the main intake passage, so by selecting the installation position of the throttle valve, the volume of the intake passage in the section from the intake valve to the throttle valve can be determined in the high and low speed intake passages. Therefore, the boost negative pressure is stable even at the idle opening position of the throttle valve, and a stable idling state of the engine is obtained, and the throttle valve opens rapidly from the idle opening position. Sometimes, the boost negative pressure changes immediately accordingly, resulting in good acceleration operation of the engine.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.A cylinder head 1 of an internal combustion engine H has a combustion chamber 2, and a suction opening on the ceiling surface of the combustion chamber 2.

Exhaust boats 3 and 4 are provided, and intake and exhaust ports 3.4
are opened and closed by intake and exhaust valves 5 and 6, respectively.

The intake port 3 has its outer end opened on the outer surface of the cylinder head 1, and a main intake passage 7 is continuously connected to this, and a high-speed intake passage 8 is connected to the upstream end of the main intake passage 7. A low speed intake path 9, which is longer in length than the high speed intake path 8, is connected in parallel. At this time, the high-speed intake passage 8 is formed to be thicker than the intake passage 9 and continuous with the main intake passage 7 so that the intake resistance is smaller than that of the low-speed intake passage 9.

Here, the intake port 3, the main intake path γ and the high speed intake path 8
0 The total length Ll is set to a length that can maximize the charging efficiency during high-speed operation of the engine E due to the intake inertia effect, and the total length L2 of the intake port 4, the main intake path 7, and the low-speed intake path 90. is set to a length that can maximize the charging efficiency during low-speed operation of the engine E due to the intake inertia effect, and the length L2 is equal to the difference in length between the high and low intake passages 8 and 9. L
It is longer than l.

The inlets of the high and low speed air intake passages 8 and 9 are opened into a common air intake chamber 10. An air intake port 10a is provided on one side of the intake chamber 10.
is provided, and an air cleaner 11 for cleaning the air taken in from the air intake port 11C is installed in the intake chamber 10.
be accommodated in.

The main intake passage 7 is provided with a throttle valve 12, and the high-speed intake passage 8 is provided with an on-off valve 13.The throttle valve 12 is provided with an accelerator operator 14 such as an accelerator pedal, and the on-off valve 13 is provided with an actuator 15. are connected to each other. The actuator 15 normally holds the on-off valve 13 in a closed state, but when the engine E enters a predetermined high-speed operating state, the actuator 15 opens the on-off valve 1 in response to this.
3 is designed to open.

In the figure, reference numeral 16 denotes a fuel injection nozzle attached to the downstream side wall of the main intake passage 7, which injects fuel toward the intake valve 5 during the intake stroke of the engine E.

Next, the operation of this embodiment will be explained. When the engine E is operating at low speed, the actuator 15 is in an inactive state, and the on-off valve 13 is in an inactive state.
The high-speed intake passage 8 is blocked by this. Therefore, the air sucked into the intake chamber 10 from the air intake port 10α during the intake stroke of the engine E passes through the low-speed intake passage 9, the main intake passage 7, and the intake port 3 in this order, and is sucked into the combustion chamber 2. The intake air amount is adjusted by a throttle valve 12.

Since the throttle valve 12 is provided in the main intake passage 7, depending on the installation position of the throttle valve 12, the throttle valve 12 can be moved from the intake valve 5 to the throttle valve 12.
The volume of the intake passage in the section up to can be freely set to a small value without being affected by the high and low speed intake passages 8 and 9. Therefore, even when the throttle valve 12 is closed to the idle opening, the boost negative pressure is stable and the engine E's idling operation can be stabilized. Furthermore, when the throttle valve 12 is rapidly opened from the idle opening, the boost negative pressure changes immediately accordingly.
Good acceleration operation of the engine E can be obtained.

Furthermore, the intake port 3, the main intake passage 7, and the low-speed intake passage 9
As mentioned above, the total length L2 is set to be relatively long so that the charging efficiency can be maximized due to the intake inertia effect when the engine E is operated at low speed, so when the throttle valve 12 is substantially fully open, The low speed output performance of engine E can be satisfied.

When the engine E enters a predetermined high-speed operating state, the actuator 15 operates to open the on-off valve 13 and introduce the high-speed intake passage 8. Then, the air sucked into the intake chamber 10 during the intake stroke of the engine E passes through the high-speed intake passage 8, which has lower intake resistance than the low-speed intake passage 9, the main intake passage 7, and the intake port 3 in order, and then enters the combustion chamber 10. is inhaled.

Therefore, the intake port 3, the main intake passage 7 and the high speed intake passage 8
As mentioned above, the total length Ll is set relatively short so that the charging efficiency can be maximized due to the intake inertia effect when the engine E is operated at a predetermined high speed.
In the substantially fully open state, the high-speed output performance of the engine E can be satisfied, and the resonance effect of the intake chamber 10 further increases the filling efficiency, thereby further improving the high-speed output performance.

When the present invention is applied to a multi-cylinder internal combustion engine, it is preferable that the inlets of the high and low speed intake passages 8 and 9 of each cylinder all open into a common intake chamber 10.

C1 Effects of the Invention As described above, according to the present invention, since the throttle valve operated by the accelerator operator is interposed in the main intake passage, the volume of the intake passage in the section from the intake valve to the throttle valve is increased.

Regardless of the low intake passage, it can be set small to improve the engine's idling stability, and as a result, the idling speed can be lowered to improve fuel economy and engine quietness. In addition, acceleration performance can also be improved.

Moreover, the high and low speed intake passages can be formed into desired shapes and dimensions without affecting the intake passage volume.
The desired high output performance of the engine can be obtained by effectively utilizing the inertial effect and the resonance effect.

[Brief explanation of drawings]

The drawing is a longitudinal side view showing an embodiment of the present invention. 2... Combustion chamber, 3... Intake port, End... Intake valve,
7... Main intake path, 8... High speed intake path, 9... Low speed intake path, 10... Intake chamber, 10d... Air intake port, 12... Throttle valve, 13... ...Opening/closing valve, 14...
Accelerator operator, 15...actuator

Claims (1)

[Claims] A high-speed intake passage and a low-speed intake passage whose length is longer than the high-speed intake passage are connected in parallel to the upstream end of a main intake passage connected to an intake port of the internal combustion engine, and an on-off valve is provided in the high-speed intake passage.
An intake system for an internal combustion engine, characterized in that the main intake passage is provided with a throttle valve operated by an accelerator operator.