JPH03281955A - Suction device for engine - Google Patents

Abstract

PURPOSE:To enhance controllability by interposing an ISC valve at the middle of a bypass passage which goes around at least one out of a plurality of throttle valves provided in series, and thereby opening/closing one throttle valve with which the bypass passage is not put side by side. CONSTITUTION:A secondary throttle valve 12, a primary throttle valve 13 and a fuel injection valve 14 are disposed in an intake passage 4 from the upstream side in order, and both of the throttle valves 12 and 13 are disposed in series mutually close to each other. A bypass passage 20 is put at the position of the primary throttle vale 13 side by side therewith to bypass the valve, and an ISC valve 22 which adjusts idle revolution with the quantity of intake air adjusted, is interposed on the bypass passage 20 in such a way that it goes around the valve. And when it is judged that an engine is in operation under high load at a high land, the secondary throttle valve 12 with which the bypass passage 20 is not put side by side, is fully opened at the time of idling, but the secondary valve 12 is concurrently controlled to be fully closed at the time when it is not judged that the engine is in operation under high load at a high land.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine intake system, and particularly relates to a plurality of throttle valves arranged in series in an intake passage, and a bypass passage that bypasses the throttle valves. This invention relates to an improvement in an engine intake system having an idle speed control valve provided in this bypass passage.

(Prior Art) Conventionally, a bypass passage has been provided in parallel connecting the upstream and downstream sides of a throttle valve provided in the intake passage of an engine, and the throttle valve is fully closed in this bypass passage. A well-known engine intake system is an engine intake system equipped with an idle speed control valve that controls the engine speed during idle operation by adjusting the flow rate of intake air supplied to the engine through the bypass passage during idle operation (Japanese Patent Laid-Open No. 62 -182447, etc.).

Furthermore, as shown in FIG. 4, an intake system in which two throttle valves b and c are arranged in series in an intake passage a of an engine is also well known.
In the intake system equipped with c, the bypass passage e in which the idle speed control valve d is interposed is arranged in parallel bypassing the two throttle valves b and c, and during idling operation, the upstream secondary throttle valve b was about to be fully opened.

(Problem to be solved by the invention) However, as mentioned above, two throttle valves b
, c, when the inner diameter of the throttle is made larger to accommodate higher output, the 1st throttle valve C is fully closed during idling operation due to the higher output. The intake negative pressure in the intake passage a on the downstream side of the secondary throttle valve C increases, and the differential pressure before and after the primary throttle valve C increases, which reduces the amount of air leaking from the primary throttle valve C section. growing. Furthermore, regarding the idle speed control flow rate taken in through the bypass passage e, the pressure difference across the idle speed control valve e increases, so the flow rate increases at the same opening degree. For this reason, the amount of air supplied during idling operation may become excessive, increasing the idling rotational speed.

In addition, the cross-sectional area of the flow passage when the idle speed control valve e is fully open cannot be set too large so that the engine speed does not increase even if the idle speed control valve e fails to fully open during idling operation.

This restriction is necessary to prevent runaway in a vehicle with an automatic transmission. However, if the idle speed control flow rate is restricted by suppressing the cross-sectional area of the flow path when fully opened, the idle speed There was a problem that there was a risk that the rotation would drop, and it was difficult to achieve both.

The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the amount of air leaking from the throttle valve section during idling operation with the throttle valve fully closed, and to improve the idle speed control flow rate. It is possible to prevent the increase of
An object of the present invention is to provide an engine intake device capable of preventing a rotation increase when an idle speed control valve fails to fully open.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a plurality of throttle valves provided in series in an intake passage of an engine, and at least one of the plurality of throttle valves is bypassed. A bypass passage is installed in parallel connecting the upstream and downstream intake passages, an idle speed control valve is installed in the middle of the bypass passage, and atmospheric pressure and external load are detected. If a high load judgment is made, other throttle valves that are not provided with the bypass passage in parallel are fully opened during engine idling, and in cases other than high-altitude, high-load semi-regular operation, the above-mentioned throttle valves are opened during engine idling. An engine intake system includes a control means for fully closing a throttle valve.

(Function) According to the engine intake system configured as described above, during idling operation other than semi-regular high-altitude and high-load operation, the throttle valves are operated not only in the parts where the bypass passages are arranged in parallel, but also in the parts where the bypass passages are not arranged in parallel. All throttle valves are also fully closed. Therefore, the resistance of the intake passage increases, and the amount of air leaking from each throttle valve portion is reduced.

Furthermore, when multiple throttle valves are fully closed, the intake negative pressure in the intake passage approaches atmospheric pressure with each throttle valve separated from the engine side toward the air cleaner side. The differential pressure becomes smaller. Therefore, if one end is connected to the intake passage between multiple throttle valves and a bypass passage is installed in parallel, the differential pressure before and after the idle speed control valve will also be reduced, and the idle speed control flow rate of the intake air supplied through the idle speed control valve will be reduced. It becomes possible to not only prevent an increase in the number of problems, but also to suppress it.

Accordingly, even if the cross-sectional area of the flow path when the idle speed control valve is fully open is set to be large, the idle control flow rate when the valve fails to fully open can be suppressed, and the increase in rotation can be kept low.

On the other hand, when determining high altitude and high load, if you fully close only the throttle valve where the bypass passage is installed in parallel and fully open the other throttle valves, the fully closed throttle valve and idle speed control valve As the differential pressure before and after each increases, the amount of air leaking from the fully closed throttle valve increases, and the idle speed control flow rate also increases, resulting in a drop in idle speed at high altitudes and high loads. can also be prevented.

(Example) Examples of the engine intake system according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a schematic configuration diagram of an engine idle speed control device according to the present invention, in which 2 is an engine;
6 is an intake passage, and 6 is an exhaust passage.

As shown in the figure, in the intake passage 4, from the upstream side, there is an air cleaner 8, an air flow meter 10, a secondary throttle valve 12, a primary throttle valve 13, and a fuel injection valve 14.
An intake air temperature sensor 16 is attached to the air flow meter 10, and a throttle position sensor 17 is attached to the second throttle valve 13 to detect its opening degree, and a throttle position sensor 17 is attached to the second throttle valve 13 to detect its fully closed state. An idle switch 18 is attached.

Secondary throttle valve 12 and primary throttle valve 13
are arranged in series and close to each other, and the primary throttle valve 13 is located at the location where the primary throttle valve 13 is installed
Connect the intake passages 4, 4 on the upstream side and the downstream side of 3 to connect the 1
A bypass passage 20 is provided in parallel for allowing the engine 2 to take in the amount of air necessary for operation during the idle state when the next throttle valve 13 is fully closed. That is, the upstream end of the bypass passage 2o is connected to the intake passage 4 between the secondary throttle valve 12 and the primary throttle valve 13.

Furthermore, an idle speed control valve 22 is attached to the bypass passage 2o to adjust the amount of intake air flowing therethrough to adjust the idle rotation speed.

A catalytic converter 24 is provided in the exhaust passage 6, and an air-fuel ratio sensor 26 is provided upstream of the catalytic converter 24 to detect the air-fuel ratio of the air-fuel mixture from the concentration of a specific gas component in the exhaust gas.

Further, high-voltage spark ignition energy is applied to the spark plug 28 provided in each cylinder at a predetermined time from a distributor 3o, and this distributor 30 has the functions of a crank angle sensor and a rotation speed sensor. It is being held.

Then, the crank angle and rotation speed detected by the distributor 3o, the intake air amount detected by the air flow meter 10, the intake air temperature detected by the intake air temperature sensor 16, the 0N-OFF of the idle switch 18, and the air-fuel ratio sensor 26 detected Various information signals such as the air-fuel ratio are input to a microcomputer 32 serving as a control means. The microcomputer 32 further includes an atmospheric pressure sensor 3.
4 and an external load sensor 36 are connected, and atmospheric pressure 3
Atmospheric pressure information signals are input from the four sensors, and load information signals from auxiliary equipment such as air conditioners and power steering are input from the external load sensor 36.

The microcomputer 32 controls the fuel injection amount by the fuel injection valve 14 and the ignition timing of the spark plug 28 based on the various information signals mentioned above, as well as the idle speed control valve 22 and the secondary throttle valve 12, which are the objects of the present invention. They are designed to perform idle speed control respectively.

That is, as is well known, the microcomputer 32 determines the basic injection amount of fuel from the intake air amount and the engine rotational speed, and further adds various corrections to this basic injection amount according to the operating state of the engine 2. In addition to controlling the operation of the fuel injection valve 14, the basic ignition timing is determined from the intake air amount and the engine rotational speed, and an advance or retardation correction is added to this basic ignition timing according to the operating state of the engine 2. The ignition timing of the spark plug 28 is controlled.

In addition, as is well known, when the idle switch 18 is ON and the actual engine speed detected by the distributor 30, which is a rotational speed sensor, is within a feedback control region below a predetermined value, the microcomputer 32 automatically adjusts the actual engine speed to a predetermined value. The opening degree of the idle speed control valve 22 is controlled by feedback so that the idle speed converges to the set target idle speed.

By the way, the difference between the present invention and the conventional one is that the primary throttle valves 13 and 2 are arranged in series in the intake passage 4.
The bypass passage 20 is arranged in parallel with the secondary throttle valve 12 by bypassing only the primary throttle valve 13, and the upstream end of the bypass passage 20 is connected to the intake passage 4 downstream of the secondary throttle valve 12. In addition to the structural difference in that the secondary throttle valve 12 is connected to the secondary throttle valve 12, there is a further difference in the opening/closing control of the secondary throttle valve 12 by the microcomputer 32.

That is, the microcomputer 32 uses the atmospheric pressure sensor 3
4 and the external load sensor 36, the idle switch is turned on and the primary throttle valve 13 is fully closed, as shown in FIG. 2(A). The secondary throttle valve 12 is fully opened in the idle operating state. On the other hand, if the high altitude/high load determination has not been made, the microcomputer 32 is configured to fully close the secondary throttle valve 12 during the idle operating state, as shown in FIG. 2(B).

Therefore, in the engine intake system configured in this manner, during idle operation other than semi-steady high-altitude and high-load operation, not only the primary throttle valve 13 in the portion where the bypass passage 20 is arranged in parallel but also the bypass passage 20 is arranged in parallel. The secondary throttle valves 12 in the parts that are not closed are also fully closed. Therefore, the intake passage resistance becomes large, and each throttle valve 12.
The amount of air leakage is reduced by 13 parts.

Furthermore, when the two throttle valves 12.13 are fully closed, the intake negative pressure in the intake passage 4 approaches atmospheric pressure every time the throttle valves 12.13 are separated from the engine side toward the air cleaner side. , the differential pressure across each throttle valve 12, 13 becomes smaller. For this reason, 1
The upstream end is connected to the intake passage 4 between the next throttle valve 13 and the secondary throttle valve 12, and the bypass passage 4
If installed in parallel, the idle speed control will be 0-/lz
The differential pressure across the valve 22 is also reduced, making it possible not only to prevent the idle speed control flow rate of intake air supplied through the idle speed control valve 22 from increasing, but also to suppress it.

Therefore, even if the cross-sectional area of the flow path when the idle speed control valve 22 is fully open is set larger,
By suppressing the idle control flow rate at the time of full throttle failure, it is possible to keep the rotational speed rise low.

On the other hand, at the time of high-altitude high-load determination, the bypass passage 20
Since only the primary throttle valves 13 in the parts where are installed in parallel are fully closed and the secondary throttle valves 12 are fully opened, the The differential pressure increases, the amount of air leaking from the fully closed primary throttle valve 13 increases, and the idle speed control flow rate also increases, thereby preventing the idle speed from dropping at high altitudes and high loads. You will be able to do it.

In the above-described embodiment, the bypass passage 20 is provided at the primary throttle valve 13 disposed on the downstream side of the intake passage 4.
Although the bypass passage 20a is shown as being arranged in parallel, the bypass passage 20a may be arranged in parallel with the secondary throttle valve 12 on the upstream side of the intake passage 4, as shown in FIG. However, in this case, contrary to the above embodiment, the microcomputer 32 similarly controls the opening and closing of the primary throttle valve 13 based on the high altitude/high load determination.

(Effects) In summary, according to the engine intake device according to the present invention, there is a plurality of throttle valves provided in series in the intake passage of the engine, and at least one of the plurality of throttle valves is bypassed. High-altitude high-load judgment is made by detecting a bypass passage that connects the upstream and downstream intake passages, an idle speed control valve installed in the middle of the bypass passage, and atmospheric pressure and external load. If the above-mentioned bypass passage is not installed in parallel, the other throttle valves are fully opened when the engine is idling, and when the engine is running at high altitude and under high load, the throttle valve with the above-mentioned function is opened fully when the engine is idling. Since the engine intake system includes a control means for fully closing the air intake system, the following excellent effects can be achieved.

(1) During idling operation other than semi-regular operation at high altitude and high load, not only the throttle valves in the parts where the bypass passages are installed in parallel, but also the throttle valves in the parts in which the bypass passages are not installed in parallel are all fully closed. The passage resistance is increased, and the amount of air leakage at each throttle valve portion can be reduced.

(2) When multiple throttle valves are fully closed,
The intake negative pressure in the intake passage approaches atmospheric pressure as each throttle valve is separated from the engine side to the air cleaner side, and the differential pressure before and after a single throttle valve becomes smaller. By connecting one end to the intake passage and installing a bypass passage in parallel, the differential pressure before and after the idle speed control valve will also be reduced, making it possible to prevent an increase in the idle speed control flow rate of the intake air supplied through the idle speed control valve. Not only will this happen, but it will also be possible to suppress it. Therefore, even if the cross-sectional area of the flow path when the idle speed control valve is fully open is set to be large, the idle control flow rate when the fully open fails is suppressed, and the increase in rotation can be kept low.

(3) When determining high altitude and high load, only the throttle valves where the bypass passages are installed are fully closed and the other throttle valves are fully opened, so the fully closed throttle valves and idle speed control valves are fully closed. The differential pressure before and after each increases, the amount of air leaking from the fully closed throttle valve increases, and the idle speed control flow rate also increases, which also reduces the drop in idle rotation at high altitudes and high loads. This can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the overall configuration of an engine equipped with an intake system according to the present invention, Fig. 2 is a schematic diagram showing the configuration of the main parts of the present invention, and Fig. 1 (A) is a schematic diagram showing the configuration of the main part of the present invention. (B) is a diagram showing the opening and closing states of the throttle valve in the case of high altitude and high load determination, and FIG. 3 shows a modified example, and FIG. A
), FIG. 4 is a schematic diagram showing a conventional intake device. 2...Engine 4...Intake passage 12...Secondary throttle valve 13...
...Primary throttle valve 20...Bypass passage 22...Idle speed control valve 32...Microcomputer (control means) 3
4... Atmospheric pressure sensor 36... External load sensor

Claims (1)

[Scope of Claims] A plurality of throttle valves provided in series in an intake passage of an engine, and an intake passage connecting an upstream side and a downstream side of the plurality of throttle valves by bypassing at least one of the plurality of throttle valves. A bypass passage installed in parallel and an idle speed
When the high altitude high load is determined by detecting the control valve, atmospheric pressure, and external load, the other throttle valves that are not parallel to the bypass passage are fully opened during engine idling, and the high altitude high load is detected. An intake system for an engine, comprising: control means for fully closing the other throttle valve during idling operation of the engine in cases other than semi-regular operation.