JPH0113790Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an EGR control device for an internal combustion engine.
In particular, the EGR amount is reduced above a predetermined vehicle speed for quantitative control, and the air-fuel ratio is diluted by supplying atmospheric air to improve drivability and fuel efficiency, while also reducing harmful CO, THC, and NOx. Regarding the engine's EGR control device.

The conventional EGR control device, as shown in Figure 1,
EGR pressure regulating valve 3 is installed in the diaphragm chamber of EGR valve 36a.
The negative pressure immediately upstream of the carburetor throttle valve 8a whose pressure is regulated by 4a is applied to this EGR pressure regulating valve 3.
A negative pressure control valve 50a is installed between the EGR valve 4a and the EGR valve 36a.
The atmospheric passage 52a of the two was connected to each other. Further, a negative pressure switching valve 18a is provided in the middle of the first passage 12a that opens immediately upstream of the carburetor throttle valve 8a, and a switching signal is output to the negative pressure switching valve 18a to open the passage at a vehicle speed below a predetermined vehicle speed. Connect the sensor 20a,
The diaphragm chamber of the air control valve 24a and the diaphragm chamber of the negative pressure control valve 50a were connected so as to act on the negative pressure control valve 18a.

Therefore, at a predetermined vehicle speed or higher, the negative pressure control valve 50a
This causes the atmosphere to act on the diaphragm chamber of the EGR valve 36a, causing the EGR valve 36a to perform a cut-off operation, so that EGR is not performed at all.
Therefore, in order to perform EGR control more effectively, it is necessary to further install a negative pressure control valve, and improvements are desired to improve drivability, fuel efficiency, and achieve even more effective exhaust purification. Ta.

Therefore, the purpose of this invention is to connect the first and second passages to the first and second ports that open immediately upstream of the carburetor throttle valve, respectively, and to provide a negative pressure switch that is switched and controlled by a vehicle speed sensor in the middle of the first passage. a valve is provided, said second
A third passage that communicates with the air control valve is connected to the passage, and a fourth passage that controls the pressure transmitted by the EGR pressure regulating valve and communicates with the EGR valve is connected in the middle of the second passage. In the case where the intake passage negative pressure from the first port and the second
The amount of EGR and the amount of atmospheric air supplied to the internal combustion engine are controlled by the negative pressure in the intake passage from the port, and at a predetermined vehicle speed or higher, the negative pressure in the intake passage from the second port and the amount of air from the atmospheric opening of the negative pressure switching valve are controlled. By controlling the amount of EGR supplied to the internal combustion engine using atmospheric pressure, the amount of EGR is reduced and controlled quantitatively at vehicle speeds above a specified speed, improving drivability.
In addition to reducing NOx and diluting the air-fuel ratio by supplying atmospheric air, it not only improves fuel efficiency, but also reduces CO2 and
The objective is to realize an EGR control device for an internal combustion engine that reduces THC.

Embodiments of this invention will be described in detail and specifically below based on the drawings. In FIGS. 2 and 3, 2 is an intake passage, 4 is a carburetor, 6 is a bench lily, and 8 is a carburetor throttle valve. A first port 10 is opened immediately upstream of the carburetor throttle valve in the intake passage 2, and a first passage 12 is communicated with the first port 10. A second port 14 is located upstream of this first port 10.
is opened, and a second passage 16 is communicated with the second port 14. A negative pressure switching valve 18 consisting of a VSV (vacuum switching valve) is provided in the middle of the first passage 12, and a switching signal is output to the negative pressure switching valve 18 to open the passage when the vehicle speed is lower than a predetermined vehicle speed. Connect the vehicle speed sensor 20. One end of the third passage 22 is communicated with the second passage 16,
The middle of this third passage 22 is connected to the negative pressure switching valve 18 as shown in the figure, and the other end of the third passage 22 is connected to the negative pressure switching valve 18 as shown in the figure.
It communicates with a diaphragm chamber 26 of an air control valve 24 consisting of an ACV (air control valve).
An atmospheric passage 28 of this air control valve 24 is communicated with a main nozzle 30 provided in the bench lily 6 of the intake passage 2.

Further, one end of the fourth passage 32 is communicated with the middle of the second passage 16, and the middle of the fourth passage 32 is connected to the EGR.
- It communicates with the EGR pressure regulating valve 34 consisting of a VM (EGR Vacuum Modulator) to control the pressure transmitted, and the other end of the fourth passage 32 communicates with the diaphragm chamber 38 of the EGR valve 36.

As a result, when the vehicle speed is lower than the predetermined speed, the
The EGR amount and atmospheric amount supplied to the internal combustion engine are controlled by the negative pressure in the intake passage from the port 10 and the negative pressure in the intake passage 2 from the second port 14, and at a predetermined vehicle speed or higher, The configuration is such that the amount of EGR supplied to the internal combustion engine is controlled by the negative pressure in the intake passage 2 and the atmospheric pressure from the atmospheric opening 46 of the negative pressure switching valve 18 while reducing the amount of EGR supplied to the internal combustion engine quantitatively.

Further, one end of the recirculation passage 40 for performing EGR is communicated with an exhaust passage (not shown), and the other end is branched into two. One of the other ends of this branch is connected to the EGR pressure regulating valve 3.
It communicates with the diaphragm chamber 42 of No. 4, and the other end
It communicates with the intake passage 2 via the EGR valve 36. Note that 44 is an ignition switch connected to the negative pressure switching valve 18, 46 is an atmospheric opening of the negative pressure switching valve 18, and 48 is an atmospheric opening of the air control valve 24.

Next, the effect will be explained.

First, as shown in FIG. 2, when the vehicle speed is lower than a predetermined speed, the ignition switch 44 is turned on and energized, and the vehicle speed sensor 20 is also turned on to open the passage of the negative pressure switching valve 18.
The atmosphere opening 46 of the negative pressure switching valve 18 is closed. As a result, the negative pressure generated in the intake passage 2 passes through the first port 10, the first passage 12, the negative pressure switching valve 18, and the second and third passages 16, 22.
transmitted to. The negative pressure transmitted to the second passage 16 merges with the negative pressure that has reached the second passage 16 from the second port 14 and is transmitted to the fourth passage 32, and the EGR
It passes through the pressure regulating valve 34 and reaches the diaphragm chamber 38 of the EGR valve 36. Then, the EGR valve 36 is opened in proportion to the negative pressure value controlled by the EGR pressure regulating valve 34 reaching the diaphragm chamber 38 of the EGR valve 36.

Thereby, exhaust gas flows into the intake passage 2 from the exhaust passage (not shown) via the recirculation passage 40. Also, at this time, through the third passage 22,
The negative pressure that reaches the diaphragm chamber 26 of the air control valve 24 actuates the air control valve 24 and closes the atmospheric opening 48 of the air control valve 24. Therefore, atmospheric air is not supplied from the atmospheric passage 28 to the intake passage 2, and the air-fuel ratio does not become lean. Note that even when the vehicle speed is lower than a predetermined speed, when the negative pressure weakens due to low load, the atmospheric opening 48 of the air control valve 24 opens, so that atmospheric air can be supplied to make the air-fuel ratio lean.

In this way, when the vehicle speed is less than a predetermined vehicle speed, the EGR amount and the atmospheric amount supplied to the internal combustion engine are controlled by the negative pressure in the intake passage 2 from the first port 10 and the second port 14.

Next, as shown in FIG. 3, when the vehicle speed reaches a predetermined speed or higher, the ignition switch 44 is turned ON and energized, and the vehicle speed sensor 20 is turned OFF to switch and close the passage of the negative pressure switching valve 18. The atmosphere opening 46 of the negative pressure switching valve 18 is opened. As a result, the negative pressure generated in the intake passage 2 passes from the first port 10 to the first passage 12 and reaches the negative pressure switching valve 18 . However, at this time, since the passage of the negative pressure switching valve 18 is closed by the vehicle speed sensor 20, the first
Negative pressure from port 10 is cut off here. Instead of this negative pressure, the atmospheric opening 4 of this negative pressure switching valve 18
The atmospheric air flowing in from the second port 14 joins the negative pressure from the second port 14, weakens this negative pressure, and flows into the second and third passages 16 and 22. This atmosphere is in the second passage 1
6, the air flows into the intake passage 2 from the second port 14 and also flows into the fourth passage 32. The air flowing into the fourth passage 32 passes through the EGR pressure regulating valve 34 and reaches the diaphragm chamber 38 of the EGR valve 36. At this time, the exhaust gas reaches the diaphragm chamber 42 of the EGR pressure regulating valve 34 via the recirculation passage 40,
Since the EGR pressure regulating valve 34 is operated to control the inflow of atmospheric air into the diaphragm chamber 38 of the EGR valve 36,
The EGR valve 36 is not fully closed and is in a controlled open state.
Therefore, the amount of EGR decreases, and a small but fixed amount of exhaust gas flows from the recirculation passage 40 into the intake passage 2.

Further, the air flowing into the third passage 22 reaches the diaphragm chamber 26 of the air control valve 24, and operates the air control valve 24 to open the air opening 48 of the air control valve 24. Therefore, the atmosphere flows into the atmosphere passage 28 through the atmosphere opening 48 of the air control valve 24, and this atmosphere flows from the main nozzle 30 into the intake passage 28.
It is used to achieve a lean air-fuel ratio.

In this way, at a predetermined vehicle speed or higher, the negative pressure in the intake passage 2 from the second port 14 and the negative pressure switching valve 1
The atmospheric pressure from the atmospheric opening 46 of No. 8 is used to control the atmospheric pressure while quantitatively reducing the EGR amount supplied to the internal combustion engine.

As is clear from the above explanation, according to this invention, the first and second
A first passage and a second passage are connected to the port, respectively, and the first passage is connected to the first passage.
A negative pressure switching valve whose switching is controlled by a vehicle speed sensor is provided in the middle of the passage, a third passage communicating with the air control valve is connected to the second passage, and a negative pressure switching valve is provided in the middle of the second passage.
Connecting a fourth passage that controls the pressure transmitted by the EGR pressure regulating valve and communicates with the EGR valve;
When the vehicle speed is lower than a predetermined vehicle speed, the EGR amount and atmospheric pressure supplied to the internal combustion engine are controlled by the intake passage negative pressure from the first port and the intake passage negative pressure from the second port. The configuration uses the intake passage negative pressure from the two ports and the atmospheric pressure from the negative pressure switching valve atmospheric opening to quantitatively reduce the amount of EGR supplied to the internal combustion engine while controlling the atmospheric amount. It is possible to reduce the amount of EGR and control it quantitatively, thereby improving drivability and reducing NOx. Furthermore, by diluting the air-fuel ratio by supplying atmospheric air, fuel efficiency is improved. It is possible to reduce the amount of CO and THC.
Furthermore, since the configuration performs the minimum amount of EGR required, EGR
In addition to improving the durability of the valve, this invention also has the advantages of simple structure, high reliability, and low manufacturing cost.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing a conventional EGR control device for an internal combustion engine. Figures 2 and 3 show an embodiment of this invention, Figure 2 is a system diagram showing an EGR control device for an internal combustion engine operating at a vehicle speed below a predetermined vehicle speed, and Figure 3 is a system diagram showing an EGR control device for an internal combustion engine operating at a vehicle speed above a predetermined vehicle speed. It is a diagram. In the figure, 2 is an intake passage, 10 is a first port, 12 is a first passage, 14 is a second port, 16 is a second passage, 18 is a negative pressure switching valve, 20 is a vehicle speed sensor, 22 is a third passage, 24 is an air control valve, 28 is an atmospheric passage, 32 is a fourth passage, 34 is an EGR pressure regulating valve,
36 is an EGR valve.

Claims (1)

[Scope of utility model registration request] A first port is opened immediately upstream of the carburetor throttle valve and a first passage communicating with the first port is provided, and a second port is opened upstream of the first port and communicating with the second port. Second
A passage is provided, a negative pressure switching valve is provided in the middle of the first passage, and a vehicle speed sensor is connected to the negative pressure switching valve to output a switching signal for opening the passage at a speed lower than a predetermined vehicle speed;
One end of the third passage is connected to the second passage, and the middle of the third passage is connected to the negative pressure switching valve, and the other end is connected to the diaphragm chamber of the air control valve, so that the air of the air control valve is connected to the diaphragm chamber of the air control valve. A passage is opened to communicate with the intake passage, and one end of the fourth passage is connected to the middle of the second passage, and the middle of the fourth passage is connected to the EGR pressure regulating valve to control the transmitted pressure and to control the pressure of the fourth passage. The other end is connected to the diaphragm chamber of the EGR valve, and when the vehicle speed is lower than a predetermined speed, the EGR amount and atmospheric amount are supplied to the internal combustion engine by the intake passage negative pressure from the first port and the intake passage negative pressure from the second port. At the same time, at a predetermined vehicle speed or higher, the amount of EGR supplied to the internal combustion engine is reduced to a fixed amount by the negative pressure in the intake passage from the second port and the atmospheric pressure from the atmospheric opening of the negative pressure switching valve. An internal combustion engine characterized by being configured to control
EGR control device.