JPH02241962A - Flow control valve - Google Patents

Abstract

PURPOSE:To simplify the structure of the secondary air passage by providing a valve element which is connected to an actuator and changed in its position along a designated axis and a valve seat which is connected to a temperature sensitive member and changed in its position along the axis common to the designated axis. CONSTITUTION:The close position of a valve element 3 at the cold time is mechanically regulated, and a temperature sensitive member 12 is contracted. Accordingly, a valve seat is displaced downward by a coiled spring 22, and the valve seat 2 is separated from an annular lip 13 of a valve element, so that a passage 4 is opened for the displacement of the valve seat 2 to increase an air flow and supply same. Secondly, a member 21 is deformed by a rise of water temperature to push up the valve seat 2, so that on the completion of warm-up, the lip 13 and the valve seat 2 are brought into close contact with each other to cut off the communication of the passage 4. At the time of stabilizing and keeping an engine speed to load fluctuation during idling, or at the time of conducting air-fuel ratio control in the engine brake state, according to each condition, a designated pulse signal is given to the starter coil 24 of a stepping motor 6 to rotate a rotor 14, whereby a required quantity of air is supplied by valve lift corresponding to the lead angle of a screw.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] <Industrial Application Field> The present invention relates to a flow control valve, and particularly to a flow control valve for secondary air in an electronically controlled fuel injection engine.

<Prior art> In an electronically controlled fuel injection engine (EFI engine), the required fuel injection amount is approximately proportional to the intake manifold internal pressure, and the intake manifold internal pressure and engine rotation speed detected by a pressure sensor are used. The fuel injection amount is controlled accordingly. Further, in the case of an EFI engine, a constant electric signal is always obtained by a throttle valve opening sensor, and the fuel is cut off during deceleration based on this signal.

Therefore, if the idling speed is adjusted using the throttle valve, the throttle valve opening sensor must be calibrated in response to changes over time, which tends to make it difficult to maintain the accuracy of the throttle valve opening signal. . Therefore, idling control is performed by closing the throttle valve and then the air flow rate in the passage that bypasses the throttle valve (
This is usually done by adjusting the secondary air.

Air flow control valves for such bypass passages include temperature-sensitive valves that respond to the water temperature and open only when the water temperature is low to increase the idling rotation speed when the engine is cold, and valves that open only when the water temperature is low to increase or decrease the idling speed of the engine when the engine is cold, and the valve that opens only when the water temperature is low. Correspondingly, there are solenoid valves that adjust the air-fuel ratio to keep the idling speed at an appropriate level, and diaphragm valves that compensate for air flow during cranking in response to negative intake pressure.

<Problems to be Solved by the Invention> However, since these control valves have different functions and different flow rate ranges to be adjusted, it is difficult to share them with each other. Therefore, each control valve must be provided individually, which leads to the inconvenience of complicating the intake system or increasing the size of the area around the throttle body.

The present invention has been made in order to improve such inconveniences, and its main purpose is to provide a flow control valve that can simplify the configuration of the secondary air passage.

[Structure of the Invention (Means for Solving the Problem) According to the present invention, the purpose is to bypass the throttle valve in an electronically controlled fuel injection engine and introduce secondary air into the intake port. A flow control valve is provided in a passageway for a flow control valve, the valve body being connected to an actuator and capable of varying its position along a predetermined axis, and the valve body being connected to a temperature-sensitive member and arranged along an axis common to the axis. This is achieved by providing a flow control valve characterized by having a valve seat whose position can be varied.

<Function> In this way, for example, an electronic control valve that changes its opening degree in response to an electrical signal and a temperature-sensitive valve that changes its opening degree in direct response to temperature changes can be integrated. I can do it. Therefore, valve opening control based on multiple different pieces of information,
This can be done with a single control valve.

<Embodiments> Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 schematically shows the structure of a flow control valve constructed based on the present invention. The flow rate control valve 1 includes a valve box 5 which includes a fluid passage 4 whose communication is interrupted by a valve seat 2 and a valve body 3 in close contact with the valve seat 2, and an actuator for driving the valve body 3 to open and close. As shown in FIG. 2, it is provided in the middle of a secondary air passage S that bypasses the throttle valve T between the air cleaner A and the intake port of the engine E.

The fluid passage 4 has an inflow port 11 and a discharge port 12 whose axes are perpendicular to each other.
The above-mentioned valve body 3 is provided so as to be displaceable along the axis of the discharge port 12 at an intermediate portion between these two ports. Further, an annular lip 13 is formed on the outer circumference of the valve body 3 so as to be in close contact with the valve seat 2.

A valve shaft 15 is screwed into the center of a rotor 14 of a stepping motor 6, which is of a known type per se. The valve shaft 15 is supported by the valve body 5 so as to be prevented from rotating and capable of reciprocating linear movement, and the valve body 3 is attached to its free end via a retainer 16. Further, the valve body 3 is normally biased to close by a coil spring 17 provided surrounding the valve shaft 15.

A diaphragm 19 hermetically isolates a cavity 18 for receiving the valve body 3, the retainer 16, and the coil spring 17 from the fluid passage 4. On the other hand, the end surface of the valve body 3 on the discharge port 12 side and the inside of the empty chamber 18 are as follows.
They communicate with each other via a leak passage 20 formed in the valve body 3 and the valve shaft 15.

On the other hand, the valve seat 2 is attached to the discharge boat 1 such that the annular lip 13 formed on the valve body 3 comes in close contact with the fluid passage 4 to cut off communication.
It is formed at the most upstream end of 2. This valve seat 2 is a flat valve seat, and is supported by a valve body 5 via a temperature-sensitive member 21 made of bimetal or the like whose shape changes according to temperature changes. It is made to be somewhat movable. At the same time, the valve seat 2 is urged by the coil spring 22 in a direction opposite to the direction of displacement due to the deformation of the temperature sensing member 21. In addition, the temperature sensing member 2
A hot water passage 23 through which cooling water flows is formed around the hot water passage 1 .

Next, the operation procedure of the above embodiment will be explained.

The stepping motor 6 rotates the rotor 14 by a predetermined angle in response to a pulse input applied to the stator coil 24. In response to the rotation of the rotor 14, the valve shaft 15 screwed to the rotor 14 performs a linear reciprocating motion, and the valve body 3
to drive.

On the other hand, the closed position of the valve body 3 when the machine is cold is mechanically defined, and on the other hand, the temperature sensing member 21 is contracted in this state. Therefore, the valve seat 2 is displaced downward in FIG. 1 by the pressing force of the coil spring 22, and the valve seat 2 is separated from the annular lip 13 of the valve body 3. As a result, the fluid passage 4 is opened by the displacement of the valve seat 2, and the air flow rate when the engine is cold is increased and supplied to the engine.

When the water temperature rises, the temperature sensing member 21 deforms and the coil spring 2
2 and push up the valve seat 2. As a result, when warm-up is completed, the annular lip 13 and the valve seat 2 come into close contact with each other, and the fluid passage 4 is disconnected from the valve seat 2.

On the other hand, when maintaining a stable engine speed in response to load fluctuations during idling, such as electrical load fluctuations, air conditioner operation, and automatic transmission range switching when stopped,
Alternatively, when controlling the air-fuel ratio when the throttle valve is suddenly closed, that is, when the engine is braking, a predetermined pulse signal is applied to the stator coil 24 of the stepping motor 6 according to the above conditions to rotate the rotor 14. make it move. As a result, a valve lift corresponding to the lead angle of the screw is obtained, and the required amount of air is supplied to the engine.

By the way, for example, in order to prevent the valve from remaining open if there is a problem with the stepping motor 6,
When the valve body 3 is always biased in the valve-closing direction by the coil spring 17 and the contact surface against the valve seat 2 is directed downstream of the intake flow line, and the driving force of the stepping motor 6 disappears, the valve closes. The lead angle of the screw is determined so that the body 3 automatically closes due to the biasing force of the coil spring 17. Therefore, when the stepping motor 6 is de-energized, the intake flow rate is automatically throttled and the engine rotational speed is reduced.

Furthermore, since the inside of the diaphragm 19 communicates with the downstream side of the intake air through the leak passage 20, the pressure inside the chamber 18 does not fluctuate even if the valve body 3 is displaced, which prevents the inconvenience of inhibiting the movement of the valve body 3. It never occurs.

Therefore, the torque for driving the valve body 3 is reduced, and the stepping motor can be made smaller.

[Effects of the Invention] As described above, according to the present invention, the opening degree of the valve can be controlled based on a plurality of different pieces of information, and a single control valve can control a small flow rate and a large flow rate. becomes possible. Therefore, the secondary air supply path is simplified, and at the same time
The number of parts is reduced, which has a significant effect on reducing manufacturing costs.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view schematically showing the device of the present invention, and FIG. 2 is an intake system diagram in which the device of the present invention is used. 1...Flow rate control valve 2...Valve seat 3...Valve body
4...Fluid passage 5...Valve box
6...Stepping motor 11...Inflow boat
12...Discharge boat 13...Annular lip 14.
...Rotor 15...Valve stem 16...Retainer 17...Coil spring 18...Vacancy 19...
Diaphragm 20...Leak passage 21...Temperature sensing member 22...Coil spring 23...Hot water passage Patent applicant Honda Motor Co., Ltd. Agent

Claims (4)

[Claims] (1) A flow control valve installed in a passage for introducing secondary air into an intake port bypassing a throttle valve in an electronically controlled fuel injection engine, which is connected to an actuator and moves along a predetermined axis. 1. A flow control valve comprising: a valve body whose position can be varied along a temperature-sensitive member; and a valve seat which is connected to a temperature-sensitive member and whose position can be varied along an axis common to the axis. (2) A sealing diaphragm is interposed between the valve body and a hole formed in the valve box to displaceably receive the valve body, and a sealing diaphragm is interposed between the valve body and the valve seat. The flow control valve according to claim 1, wherein a contact surface side and a space in contact with the inner surface of the diaphragm communicate with each other. (3) The valve body is always biased by a spring toward the valve seat, and the contact surface side of the valve body with the valve seat faces downstream of the intake flow line. The flow control valve according to claim 1 or 2. (4) The valve seat is always biased by a spring in a direction away from the valve body, and is supported by the valve body via bimetal means capable of generating a holding force that counteracts the spring biasing force. The flow control valve according to claim 1, characterized in that: