JPS6138342B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust gas recirculation device, and more particularly to an exhaust gas recirculation device that varies the amount of exhaust gas recirculated in response to the exhaust gas pressure in an exhaust manifold.

Conventionally, in an exhaust gas recirculation device that has a recirculation control valve that opens a recirculation circuit in response to a signal negative pressure generated in response to the vehicle operating condition, a carburetor is used to maintain a constant exhaust gas recirculation rate. In order to vary the amount of exhaust gas recirculated in response to the amount of air flowing through the exhaust manifold or the air flow rate, that is, the exhaust gas pressure at the exhaust manifold, a diaphragm type compensation valve means operated in response to the exhaust gas pressure is used. Methods have been proposed to bleed atmospheric air into the signal vacuum passage for recirculation control valve actuation.

Furthermore, as described in, for example, Japanese Patent Application Laid-Open No. 52-61631, a pressure regulating valve device has been proposed to keep the pressure in the exhaust gas pressure chamber constant. However, the above-mentioned type of correction valve means or pressure regulating valve device is a mechanical control system equipped with a diaphragm piston, and cannot accurately respond to high-frequency pulsating exhaust gas pressure due to diaphragm activation delay, hysteresis, etc. Additionally, there was a problem in that the diaphragm of the correction valve means or the pressure regulating valve device was eroded and corroded by the exhaust gas, resulting in reduced durability.

In view of the problems of the prior art described above, the technical object of the present invention is to improve the operational response to exhaust gas pressure.

The technical means taken to solve the above-mentioned technical problem is that the recirculation circuit is disposed in the recirculation circuit and the signal negative pressure generated in response to the operating state of the vehicle, that is, the opening degree of the throttle valve, is activated. A recirculation control valve that opens a recirculation circuit, and detecting exhaust gas pressure in the recirculation circuit that is upstream of the recirculation control valve, and generating an output electric signal by comparing a response electric signal and a set electric signal. a control circuit for correcting the signal negative pressure for actuating the recirculation control valve in response to the output electrical signal of the control circuit, and adjusting the amount of recirculation of exhaust gas in response to the exhaust gas pressure of the exhaust manifold; The control valve is a minute flow rate proportional control valve having a variable correction valve means, the correction valve means being constituted by a moving coil type linear motor, and equipped with a slide valve that controls a minute air flow rate in proportion to an input current value. ,
That's true.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

10 is connected to the exhaust manifold and forms the upstream side of the exhaust gas recirculation passage, and is disposed between a passage 11 having an orifice 11a and a passage 13 connected to the intake manifold 12 and forming the downstream side of the exhaust gas recirculation passage. This is an exhaust gas recirculation control valve. The outer periphery of the control valve 10 is sandwiched between the body 14 and a signal negative pressure chamber 15 is formed in the body 14.
and a diaphragm 17 that partitions an atmospheric pressure chamber 16, and a valve piston 20 having a valve portion 19 fixed to the diaphragm 17 and disposed at its tip corresponding to a seat 18 formed on the body 14,
Since the tip of the valve portion 19 is formed into a tapered shape, the recirculation passage 1 is opened according to the distance from the seat 18.
The amount of exhaust gas recirculation from 1 to 12 can be controlled proportionally. The signal negative pressure chamber 15 is connected via a passage 21 to a port 22 of the carburetor. The port 22 is disposed on the upstream side of the throttle valve 23 when the throttle valve 23 is not in operation, and is positioned downstream when the throttle valve 23 is rotated counterclockwise, so that the throttle valve 23 is not operated. Negative pressure is generated in response to the opening degree of the valve 23. Diaphragm 17 is therefore displaced against spring 24 in response to negative pressure from port 22, and valve portion 19 is thus responsively controlled away from seal 18.

The pressure sensor 25 is connected to the recirculation passage 11 and functions to detect the exhaust gas pressure in the exhaust gas pressure chamber 26 upstream of the valve portion 19 and convert it into a response voltage signal. The response voltage signal is transmitted to the control circuit 2.
7, and the other end of the comparator 28 is connected to a potentiometer 29, which adjusts the voltage division ratio as appropriate manually or the like, and is configured to receive a set voltage signal. Ru. In this way, the comparator 28 compares the exhaust gas pressure response voltage signal and the prerequisite voltage signal and generates an output electrical signal responsive to the difference.

Reference numeral 31 designates a minute flow rate proportional control valve whose operation is controlled by an output electric signal from the control circuit 27 received via the cord 30. The flow control valve 31 is
Inlet port 32 and outlet port 33
a first body 34 having a terminal terminal 3;
5 and 36 are integrally and airtightly connected via a sealing agent 38 made of rubber, thereby forming its outer shape. A spool 39 is disposed inside the first body 34, and an iron core 41 made of a magnetic material is provided in the shaft hole 40 of the spool 39.
is inserted. An armature 42 is slidably disposed on the spool 39.
An electromagnetic coil 43 is wound on 2. Furthermore,
A pair of permanent magnets 44, 45 are arranged so that the magnetic flux passes perpendicularly to the winding of the electromagnetic coil 43, and a yoke or magnetic frame 46 surrounds the permanent magnets 44, 45 to form a magnetic flux path, that is, a magnetic path. are arranged to constitute a moving coil type linear motor. A guide member 47 made of a non-magnetic material is fitted into the yoke 46, and the guide member 47 and the shoulder portion 48 of the first body 34 connect the permanent magnets 44, 4.
5 is retained.

A complicated orifice 50 is provided on the spool 39 to communicate the shaft hole 40 inside the spool 39 with a chamber 49 formed in the outer circumference thereof, that is, in the first body 34 . A slide valve 51 made of a non-magnetic material such as brass or stainless steel is inserted and fixed into the inner periphery of the armature 42, and the orifice 5
The opening of the 0 chamber 49 can be slid together with the armature 42. That is, the armature 4 responds proportionally to the current value applied to the electromagnetic coil 43.
A slide valve 51 integrally connected to 2 is actuated and displaced to control opening and closing of the orifice 50. The shaft hole 40 communicates with the inlet port 32 via a communication hole 52 formed at the shaft end of the spool 39, and at the same time, the orifice 50 and the slide valve 5
1. It communicates with the outlet port 33 via the chamber 49. Therefore, fluid communication between the two ports 32 and 33 is proportionally controlled in response to the signal current value. The film 53 attached to the shaft hole 40 is used to remove dust and foreign matter from the fluid, and the O-ring 54 is used to ensure sealing between the inlet port 32 and the chamber 49. It is something.

Two coil springs 55 and 56 having different center diameters are tensioned in the chamber 49, and the armature 42 is always biased to the left in the figure by both springs 55 and 56, and as a result, the slide valve 51
is biased to a position where the plurality of orifices 50 are fully closed. One end of the spring 55 is connected to one end of the electromagnetic coil 43 via a terminal 57, and the other end is connected to the terminal terminal 35. Similarly, the spring 56 has one end connected to the electromagnetic coil 4.
3 via a terminal 58, and the other end is connected to the terminal terminal 36. The terminal terminals 35 and 36 are connected to lead wires 30 and 59.

Now, the inlet port 32 is the air cleaner 6.
0 and the vent lily 62 of the carburetor 61, while the outlet port 33 communicates with the chamber 15 of the exhaust gas recirculation control valve 10.
is connected to.

In the system of the present invention configured as described above, when the throttle valve 23 is stepped on, a negative pressure corresponding to the degree of opening is generated in the port 22, and the passage 21 is configured so that the negative pressure displaces the diaphragm 17 upward. is transmitted to chamber 15 via. Therefore, depending on the magnitude of the negative pressure, the valve portion 19 of the valve piston 20 separates from the seat 18 to control the recirculation of exhaust gas from the passages 11 to 13.

During the above-mentioned exhaust gas recirculation action, the exhaust gas pressure chamber 2
6 is detected by the pressure sensor 25, the detected value is compared with a set value by the control circuit 27, and the difference signal is sent to the flow control valve 3.
1.

The flow rate control valve 31 normally has permanent magnets 44 and 45.
The magnetic flux generated from the iron core 41 and the yoke 46
A closed loop is formed through the coil, a part of which communicates with the electromagnetic coil 43. In this state, as the detected exhaust gas pressure decreases, the current flowing through the electromagnetic coil 43 increases, and according to the well-known Fleming left hand rule, a force proportional to the current value is generated in the right direction in the figure. Therefore, the slide valve 51 integrated with the armature 42 is connected to the springs 55 and 56.
It is actuated and displaced to the right in the figure in proportion to the current value against the urging force of , and the orifice 50 is opened. At this time, the opening aperture of the orifice 50 is the same as that of the slide valve 51.
is proportionally controlled in response to the amount of rightward displacement. Therefore, the amount of communication between both ports 32 and 33 is directly controlled by the magnitude of the current value. will be bred.

In this way, depending on the exhaust gas pressure in the exhaust gas pressure chamber 26 upstream of the recirculation control valve 10, the signal chamber 1
It becomes possible to correct the operation negative pressure communication to 5. As the clogging and exhaust gas pressure decrease, the above-mentioned atmospheric bleed amount is increased, the separation of the valve portion 19 from the seat 18 is decreased, and the exhaust gas recirculation amount is decreased, thereby reducing the exhaust gas pressure. This is to maintain the exhaust gas pressure within the chamber 26 constant.

As described above in detail, in the exhaust gas recirculation control device according to the present invention, the exhaust gas pressure on the upstream side of the exhaust gas recirculation control valve is directly detected by the pressure sensor and converted into a response electric signal. The system corrects and controls the recirculation amount according to the value, making it possible to keep the recirculation rate constant, and by replacing it with an electric signal, it reduces the high frequency of exhaust gas pressure compared to conventional systems that use mechanical control. It can completely respond to pulsation, and can prevent corrosion of various parts due to exhaust gas pressure, etc., and has extremely excellent practical effects.

Further, in the present invention, since the correction valve means is a minute flow rate proportional control valve equipped with a slide valve that controls a minute amount of air in proportion to the input current value,
This further improves control accuracy.

[Brief explanation of the drawing]

1 is a diagram of an exhaust gas recirculation device according to the invention, including a partially sectional view; FIG. 10... Exhaust gas recirculation control valve, 11, 13...
... Exhaust gas recirculation passage, 12 ... Intake manifold, 25 ... Pressure sensor, 26 ... Exhaust gas pressure chamber, 27 ... Control circuit, 31 ... Flow rate control valve, 21 ... Slide valve.

Claims (1)

[Claims] 1. In an exhaust gas recirculation device that recirculates a portion of the exhaust gas in the exhaust manifold to the intake manifold via the exhaust gas recirculation circuit, the exhaust gas recirculation device is disposed in the recirculation circuit and is controlled by the operating state of the vehicle, that is, a recirculation control valve that opens the recirculation circuit in response to a signal negative pressure generated in response to a throttle valve opening;
a pressure sensor that detects the exhaust gas pressure in the recirculation circuit that is upstream of the recirculation control valve and converts it into a response electric signal; and a pressure sensor that compares the electric signal of the pressure sensor with a set signal to generate an output electric signal. a control circuit for correcting the signal negative pressure for actuating the recirculation control valve in response to the output electrical signal of the control circuit; and adjusting the amount of recirculation of exhaust gas in response to the exhaust gas pressure of the exhaust manifold. a small flow rate proportional control valve, the correction valve means comprising a moving coil type linear motor and having a slide valve that controls a small air flow rate in proportion to an input current value. , an exhaust gas recirculation device.