JPS5827084Y2 - Exhaust gas recirculation control device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an exhaust gas recirculation control device for internal combustion engines such as automobiles. Related to circulation control device.

It is preferable that the exhaust gas recirculation of a vehicle internal combustion engine be stopped quickly when the vehicle transitions from a steady running state to a decelerating state, but if there is a response delay or so-called EGR cut-off delay, it may be stopped at the beginning of deceleration. The necessary excess exhaust gas is recirculated, causing a temporary misfire of the internal combustion engine and a vehicle shock in which the vehicle vibrates back and forth.

Such EGR cut-off delay during deceleration is caused by the introduction of negative pressure adjusted according to the exhaust pressure by a negative pressure adjustment valve into a diaphragm chamber defined on one side of the diaphragm of the exhaust gas recirculation control valve. This is particularly noticeable in a back pressure control type exhaust gas recirculation control device that is configured to increase the amount of valve opening as the negative pressure increases, in other words, to increase the amount of exhaust gas recirculation.

This is because the back pressure control type exhaust gas recirculation control device has a throttling element in the middle of its negative pressure conduit, and the exhaust gas recirculation control valve uses negative pressure adjusted according to the exhaust pressure. is activated, there is a response delay equivalent to the gas penetration time in the engine until the exhaust gas volume decreases in response to the sudden decrease in intake air volume due to the sudden closing of the throttle valve, and the exhaust pressure decreases. There is a particular thing.

In contrast, conventionally, the chamber provided on the other side of the diaphragm of the exhaust gas recirculation control valve, which is generally open to the atmosphere, is not opened to the atmosphere, and this chamber is opened when the throttle valve is in the idling opening position. At a certain time, when the throttle valve located downstream of the throttle valve is opened to a predetermined opening degree or more, the intake pipe negative pressure appearing at the intake pipe negative pressure extraction port located at the upstream side of the throttle valve is introduced into the chamber. During deceleration when the throttle valve is closed to the idling opening position, the diaphragm of the exhaust gas recirculation control valve is driven in the opening direction by the intake pipe negative pressure appearing at the intake pipe negative pressure outlet port. It has been considered to quickly close the exhaust gas recirculation control valve to avoid the EGR cutoff delay.

According to this configuration, the intended purpose is achieved, and
When the throttle valve is opened beyond the intake pipe negative pressure outlet port and atmospheric pressure is substantially acting on the port, the exhaust gas recirculation control valve separates the diaphragm from the diaphragm chamber as before. 'C The opposing chambers are opened to the atmosphere and exhaust gas recirculation control is performed with the initially set characteristics; however, when the throttle valve is opened relatively wide and the engine is rotated at a relatively high speed, the above-mentioned Substantial intake pipe negative pressure appears at the intake pipe negative pressure outlet port, which acts in the direction of closing the exhaust gas recirculation control valve, so the exhaust gas recirculation control valve recycles the exhaust gas with the initially set characteristics. If circulation control is no longer performed and the intake pipe negative pressure appearing at the intake pipe negative pressure outlet port exceeds the opening set pressure of the exhaust gas recirculation control valve, exhaust gas recirculation will occur even in the area where EGR is to be performed. Circulation becomes discontinued.

In view of the above-mentioned problems with the conventional exhaust gas recirculation pedestal system, the present invention aims to effectively avoid the EGR cut-off delay during deceleration and disturb the exhaust gas recirculation control characteristics in the EGR operating range. The object of the present invention is to provide an improved exhaust gas recirculation control device that eliminates the

This purpose, according to the present invention, is achieved by defining a first diaphragm chamber on one side of the diaphragm and a second diaphragm chamber on the other side, and a negative electrode introduced into the first diaphragm chamber. The exhaust gas recirculation control valve includes an exhaust gas recirculation control valve that operates to increase its opening amount in response to an increase in pressure, defines a constant pressure chamber in the middle of the exhaust gas recirculation passage, and maintains the pressure of the constant pressure chamber at a constant level. In a pressure-controlled exhaust gas recirculation control device, a negative pressure control valve selectively connects the second diaphragm chamber of the exhaust gas recirculation control valve to an intake pipe negative pressure outlet port and an atmosphere release port. The negative pressure control valve connects the second diaphragm chamber to the intake pipe negative pressure outlet port when the intake pipe negative pressure introduced into the diaphragm chamber is larger than a predetermined value, and connects the second diaphragm chamber to the intake pipe negative pressure takeout port. When the intake pipe negative pressure to be introduced is not greater than a predetermined value, the second diaphragm chamber is connected to the atmosphere release port, and the predetermined value is set at a high speed when the internal combustion engine incorporating the exhaust gas recirculation control device is running at high speed. Exhaust gas recirculation control configured to have a value greater than an intake pipe negative pressure when the internal combustion engine is operated under load and smaller than an intake pipe negative pressure when the internal combustion engine is operated with a throttle valve closed. achieved by the device.

According to this configuration, the second diaphragm chamber of the exhaust gas recirculation control valve is connected to the intake pipe negative pressure outlet port only when the intake pipe negative pressure is larger than a predetermined value, that is, only during idling operation or deceleration operation. Since intake pipe negative pressure is introduced into the second diaphragm chamber, a delay in exhaust gas recirculation is avoided, and in the EGR operating range, the second diaphragm chamber is substantially exposed to the atmosphere. The exhaust gas recirculation control valve is opened and the exhaust gas recirculation control by the exhaust gas recirculation control valve is not disturbed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings.

The attached figure is a schematic diagram showing one embodiment of the exhaust gas recirculation control device according to the present invention.

The exhaust gas recirculation control valve 1 has a valve housing 4 having an exhaust gas inlet port 2 and an exhaust gas outlet port 3, said exhaust gas inlet port 2 being connected via a conduit 6 to an exhaust passage 7 of an internal combustion engine 5. , the exhaust gas outlet port 3 is connected to the conduit 8
are connected to the intake passages 9 of the internal combustion engine 5 through the exhaust passages 7 and 9, respectively, so that exhaust gas is recirculated from the exhaust passages 7 to the intake passages 9.

The valve port 1 is connected between the exhaust gas inlet port 2 and the exhaust gas outlet port 3 of the valve housing 4 by a valve seat portion 10.
1 is defined, and the valve port 11 is connected to the valve seat portion 10.
It is adapted to be opened and closed by a valve element 12 cooperating with the valve element 12 .

Valve element 12 is carried on valve rod 13 and
is connected to the diaphragm 14 and driven by the diaphragm 14.

The diaphragm 14 cooperates with the casing 15 to define a first diaphragm chamber 16 on its upper side and a second diaphragm chamber 17 on its lower side.

A compression coil spring 18 is provided in the first diaphragm chamber 16 to urge the diaphragm 14 downward in the figure, that is, in the valve closing direction.

The first diaphragm chamber 16 is located upstream of the throttle valve 19 provided in the intake passage 9 when the throttle valve 19 is at the idling opening position as shown in the figure. It is connected via a conduit 21 to a first intake pipe negative pressure extraction port (EGR port) 20 which opens into the intake passage 9 so as to be located on the downstream side of the intake pipe when the intake pipe is opened.

In this embodiment, a throttle element 22 and a negative pressure regulating valve 23 are provided in the middle of the conduit 21 in order to achieve backpressure-controlled exhaust gas recirculation.

As is well known, the negative pressure regulating valve 23 operates in response to exhaust pressure in a constant pressure chamber 25 provided between the valve seat 10 of the exhaust gas recirculation control valve 1 and the orifice element 24. , atmospheric air is selectively introduced into the conduit 21 to appropriately reduce and adjust the intake pipe negative pressure within the conduit.

Said second diaphragm chamber 17 is connected via a conduit 27 to a negative pressure control valve 28 .

The negative pressure control valve 28 has a valve element 31 selectively connecting the conduit 27 to one end of the conduit 29 and to one side of the atmospheric release port 30.

The valve element 31 is carried by a valve rod 32 which is connected to and driven by a diaphragm 33.

The diaphragm 33 cooperates with a casing 34 to define a diaphragm chamber 35 on the upper side in the drawing, and a compression coil spring 36 provided in the diaphragm chamber 35.
It is urged downward in the figure by the spring force.

The diaphragm chamber 35 is located downstream of the throttle valve 19 when the throttle valve 19 is at the idling opening position, and is located upstream of the throttle valve 19 when the throttle valve 19 is opened to the first opening position or more. A conduit 38 is connected to the second intake pipe negative pressure outlet port 37 that is open toward the inside of the intake pipe 9.
It is connected via.

Further, one end of the conduit 29 is also connected to the second intake pipe negative pressure outlet port 37 .

The exhaust gas recirculation control device configured as described above operates as follows.

When the throttle valve 19 is not opened beyond the first intake pipe negative pressure outlet port 20, that is, during idling, no intake pipe negative pressure acts on the first intake pipe negative pressure outlet port 20. , substantially atmospheric pressure is present, so that the exhaust gas recirculation control valve 1 is in the closed state and the recirculation of the exhaust gas is stopped.

At this time, if the operating set pressure of the negative pressure control valve 28 is set to the value of the intake pipe negative pressure corresponding to idling operation, the valve element 31 is activated by the intake pipe negative pressure introduced into the diaphragm chamber 35. It is displaced upward in the figure against the action of the spring 36, and the conduit 27 and the conduit 29 are connected in communication, so that at this time, the second intake pipe negative pressure outlet port 3
The intake pipe negative pressure appearing at 7 is the exhaust gas recirculation control valve 1.
The valve element 12 of the exhaust gas recirculation control valve 1 is introduced into the second diaphragm chamber 17 in addition to the spring force of the compression coil spring 18 and acts on the diaphragm 14. The exhaust gas recirculation control valve 1 is also driven in the valve closing direction by the force of the intake pipe negative pressure, and the exhaust gas recirculation control valve 1 is more reliably maintained in the closed state.

When the throttle valve 19 is opened beyond the first intake pipe negative pressure outlet port 20, the second intake pipe negative pressure outlet port 37 is located upstream of the throttle valve 19 and is at the same time substantially at atmospheric pressure. Because it will be affected by
The inside of the diaphragm chamber 35 of the negative pressure control valve 28 becomes almost atmospheric pressure, and the valve element 31 moves downward in the figure due to the spring force of the compression coil spring 36, replacing the conduit 27 with the conduit 29 and connecting it to the atmosphere release port 30. Become connected.

This opens the second diaphragm chamber 17 of the exhaust gas recirculation control valve 1 to the atmosphere.

At this time, substantial intake pipe negative pressure appears in the negative intake port 20, and the intake pipe negative pressure is regulated to be reduced by the negative pressure regulating valve 23 through the conduit 21, and the exhaust gas is recirculated. By being introduced into the first diaphragm chamber 16 of the control valve 1, the exhaust gas recirculation control valve 1 is opened and exhaust gas recirculation is performed.

When the throttle valve 19 is opened relatively wide and the engine 5
When the is operated at a relatively high speed, intake pipe negative pressure (negative pressure of about 10 to 50 imHg) also acts on the second intake pipe negative pressure outlet port 37, and the intake pipe negative pressure is transferred to the conduit 38. However, the negative pressure control valve 2B does not operate at such a negative pressure and maintains the state in which the conduit 27 is connected to the atmosphere release port 30.

Therefore, the second diaphragm chamber 17 of the exhaust gas recirculation control valve 1 is open to air except during idling or deceleration operation, so that the exhaust gas recirculation control valve 1 is kept open even during high-load, high-speed operation. Exhaust gas recirculation control is performed using the initial operating characteristics.

When the throttle valve 19 is suddenly closed from the load operation opening position as described above to the idling opening position as shown in the figure in order to perform deceleration, the amount of intake air flowing through the intake passage 9 is suddenly reduced, and the second intake pipe negative A large negative pressure greater than the operating set pressure of the negative pressure control valve 28 comes to act on the pressure extraction port 37.

This negative pressure is immediately introduced into the diaphragm chamber 35 of the negative pressure control valve 28 via the conduit 38.

This causes the valve element 31 to be displaced upward in the figure against the spring force of the helical compression spring 36, and connects the conduit 27 to the conduit 29 instead of the atmosphere release port 30, thereby causing the second intake air The intake pipe negative pressure present at the pipe negative pressure outlet port 37 is immediately introduced into the second diaphragm chamber 17 of the exhaust gas recirculation control valve 1 via the conduit 29, the negative pressure control valve 28, and the conduit 27, and the diaphragm 14 This acts to drive the valve element 12 downward in the figure, that is, in the valve closing direction.

Therefore, even if negative pressure is still introduced into the first diaphragm chamber 16 at this time, the valve element 12 seats on the valve seat 10 at the same time as deceleration and closes, stopping exhaust gas recirculation. Become.

This avoids EGR cut-off delay during deceleration.

In the above-described embodiment, the conduit 29 is connected to the second intake pipe negative pressure outlet port 37, but this conduit may be used as long as it is a port to which substantial intake pipe negative pressure is applied during deceleration or idling. It may be connected to a port other than the second intake pipe negative pressure outlet port.

Furthermore, if the operating set pressure of the negative pressure control valve 28 is set so that the switching operation is performed only when a negative pressure greater than the negative pressure in the intake pipe that corresponds to deceleration or idling is applied, the diaphragm chamber 35 of the negative pressure control valve 28 is set to switch. is always throttle valve 1
It may be connected to an intake pipe negative pressure extraction port located on the downstream side of 9.

Although the present invention has been described in detail with respect to specific embodiments above, it is clear to those skilled in the art that the present invention is not limited to this and that various embodiments can be made within the scope of the present invention. Will.

[Brief explanation of the drawing]

The attached figure is a schematic diagram showing one embodiment of the exhaust gas recirculation control device according to the present invention. 1; Exhaust gas recirculation control valve; 2; Exhaust gas inlet port;
3; Exhaust gas outlet port; 4; Valve housing; 5; Internal combustion engine; 6; Conduit; 7; Exhaust passage; 8; Conduit; 9; Intake passage; ,
13; Valve rod, 14; Diaphragm, 15; Casing, 16; First diaphragm chamber, 17; Second diaphragm chamber, 18; Compression coil spring, 19; Throttle valve, 20; First intake pipe negative pressure outlet Port, 21; Conduit, 22; Restriction element, 23: Negative pressure regulating valve, 24; Orifice element, 25; Constant pressure chamber, 27: Conduit, 28; Negative pressure control valve, 29; Conduit, 30; Atmospheric release port, 31 ; Valve element, 32; Valve rod, 33; Diaphragm, 34; Casing, 35; Diaphragm chamber, 36; Compression coil spring,
37; second intake pipe negative pressure outlet port; 38; conduit.

Claims (1)

[Scope of utility model registration request] A first diaphragm chamber is defined on one side of the diaphragm and a second diaphragm chamber is defined on the other side, and the opening amount thereof is adjusted according to an increase in the negative pressure introduced into the first diaphragm chamber. including an exhaust gas recirculation control valve operative to increase the exhaust gas recirculation control valve;
In the back pressure control type exhaust gas recirculation control device which defines a constant pressure chamber in the middle of the exhaust gas recirculation passage and keeps the pressure of the constant pressure chamber constant, the second exhaust gas recirculation control valve a negative pressure control valve that selectively connects a diaphragm chamber to an intake pipe negative pressure outlet port and an atmosphere release port, and the negative pressure control valve is arranged so that the intake pipe negative pressure introduced into the diaphragm chamber is lower than a predetermined value. When the negative pressure in the intake pipe is large, the second diaphragm chamber is connected to the intake pipe negative pressure outlet port, and when the intake pipe negative pressure introduced into the diaphragm chamber is not larger than a predetermined value, the second diaphragm chamber is connected to the atmosphere release port. and the predetermined value is greater than the intake pipe negative pressure when the internal combustion engine incorporating the exhaust gas recirculation control device is operated at high speed and under high load when the internal combustion engine closes the throttle valve. An exhaust gas recirculation control device configured to have a value less than the intake manifold negative pressure during operation.