JPS6320854Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to improving the EGR device of a supercharged internal combustion engine, and in particular, prevents the negative pressure chamber of the EGR control valve from becoming positive pressure during supercharging, and prevents the negative pressure chamber from becoming positive. Prevents the diaphragm bead from inverting,
The present invention also relates to an EGR device for a supercharged internal combustion engine that is capable of releasing negative pressure from a negative pressure chamber.

EGR equipment (exhaust gas recirculation equipment)
This is a device that reduces NOx production by recirculating a portion of inert exhaust gas to the intake system and mixing it into the intake air-fuel mixture. This device controls the circulation of exhaust gas.
The EGR control valve uses the negative pressure generated within the intake system to perform its control. In other words, the flexible diaphragm that partitions the negative pressure chamber in the EGR control valve that communicates with the intake system is sucked in by negative pressure, and the force that opens the valve that shuts off the circulation of exhaust gas is combined with the force that causes the diaphragm to open. It is controlled by the balance with the force of pressing and closing the valve. However, in a supercharged internal combustion engine, positive pressure is generated in the intake system during supercharging, and that positive pressure flows into the negative pressure chamber of the EGR control valve, unilaterally changing the conventional balance between negative pressure and the force of the engine. and flip the diaphragm bead that separates the negative pressure chamber to the valve closing side (second
In Figures A and B), there was a drawback that caused problems in opening and closing the valves thereafter.

Therefore, the purpose of this invention is to eliminate the above drawbacks,
To prevent the bead of a diaphragm of an EGR control valve from being reversed during supercharging with a simple structure, to prevent the control function of the EGR control valve from deteriorating, and to improve a device used in a conventional EGR system. The object of the present invention is to realize an EGR device for a supercharged internal combustion engine that can be used as is without any problems and can also release negative pressure from a negative pressure chamber without sudden pressure fluctuations.

In order to achieve this objective, this invention provides an EGR system with an EGR control valve used in a supercharged internal combustion engine, and provides a negative pressure intake in the intake system, and connects the negative pressure intake to the EGR control valve. A check valve that prevents positive pressure from the intake system from flowing into the negative pressure chamber is provided in the middle of the negative pressure passage that communicates with the pressure chamber, and a bypass passage that communicates with the upstream side of the turbocharger is connected to the negative pressure passage. The present invention is characterized in that a branched negative pressure passage is provided between the pressure chamber and the check valve, and a throttle portion is provided in the middle of this bypass passage.

Embodiments of this invention will be described in detail and specifically below based on the drawings.

Reference numeral 2 denotes a turbocharger, which is a supercharger. The turbocharger 2 forcibly increases the amount of intake air in order to improve the filling efficiency of the engine and increase output, and utilizes exhaust energy. Reference numeral 4 denotes a carburetor installed downstream of the turbocharger 2 via a surge tank 6, and a negative pressure intake port 10 is opened immediately upstream of the throttle valve 8 installed in the carburetor 4. has been done. 12 is an intake passage, and the intake passage 12 is
It constitutes the intake system, and includes an air cleaner 14,
The turbocharger 2, surge tank 6, carburetor 4, and combustion chamber 16 are communicated with each other. Further, in the intake passage 12 between the carburetor 4 and the combustion chamber 16,
The exhaust gas is passed through the intake passage 1 between the carburetor 4 and the combustion chamber 16.
A reflux outlet 18 is provided for refluxing the flow into the reflux chamber 2 .

Reference numeral 20 denotes an EGR control valve constituting the EGR device, and the EGR control valve 20 is composed of a negative pressure chamber 22, an atmospheric chamber 24, a valve chamber 26, and a retention chamber 28. Incidentally, the negative pressure chamber 22 and the atmospheric chamber 24 are partitioned by a flexible diaphragm 30, and in order to facilitate the displacement of the diaphragm 30 toward the negative pressure chamber 22, the diaphragm 30 has a flexible diaphragm 30. A bead 30a protruding toward the 22 side is formed. Further, the valve chamber 26 is provided with a valve 32 that moves forward and backward in conjunction with the displacement of the diaphragm 30. This valve 32 has a function of opening and closing a communication port 34 that communicates the valve chamber 26 and the retention chamber 28 by moving forward and backward. Reference numeral 36 denotes a spring provided in the negative pressure chamber 33. The spring 36 presses the diaphragm 30 and acts in the direction of sealing the communication port 34 with the valve 32.

38 is a negative pressure passage that communicates the negative pressure intake port 10 and the negative pressure chamber 22, and 40 is a check valve provided in the middle of the negative pressure passage 38. This check valve 40 allows communication between the intake passage 12 immediately upstream of the throttle valve 8 and the negative pressure chamber 22 when the intake passage 12 immediately upstream of the throttle valve 8 has a negative pressure, and also , has a function of blocking communication between the intake passage 12 immediately upstream of the throttle valve 8 and the negative pressure chamber 22 when the pressure inside the intake passage 12 immediately upstream of the throttle valve 8 is positive. Therefore, it is possible to prevent the negative pressure chamber 22 from becoming a positive pressure. 42 is a bypass passage branched from the middle of the negative pressure passage 38 between the negative pressure chamber 22 and the check valve 40. This bypass passage 42 communicates with the air cleaner 14 located upstream of the turbocharger 2, but is not limited thereto, and may directly communicate with the atmosphere. 44
is a constriction part provided in the middle of the bypass passage, and this constriction part 44 functions to prevent sudden fluctuations in the negative pressure in the negative pressure chamber 22 that communicates with the air cleaner 14 via the bypass passage 42. . 46
is an exhaust passage that communicates the combustion chamber 16, the turbocharger 2, and the catalyst device 48. A circulation passage 50 branches from the exhaust passage 46 between the combustion chamber 16 and the turbocharger 2 and communicates with the retention chamber 28;
Reference numeral 52 denotes a reflux passage that communicates the valve chamber 26 and the reflux outlet 18;
means the intake passage 12 between the carburetor 4 and the combustion chamber 16.
This is a passage for exhaust gas that is recirculated into the interior.

Since this invention is constructed as described above, it operates as follows.

When the intake passage 12 immediately upstream of the throttle valve 8 has negative pressure during natural air supply, the check valve 40 connects the negative pressure chamber 22 and the intake passage 1 immediately upstream of the throttle valve 8.
2, the negative pressure chamber 22 becomes negative pressure, and the diaphragm 30 is sucked toward the negative pressure chamber 22,
The diaphragm 30 is displaced toward the negative pressure chamber 22 against the spring 36 that presses and biases the diaphragm 30. In conjunction with this displacement, the valve 32 moves back and opens the communication port 34, allowing the exhaust gas to flow between the carburetor 4 and the combustion chamber 1.
The air is refluxed into the intake passage 12 between 6 and 6.

On the other hand, during supercharging, the inside of the intake passage 12 immediately upstream of the throttle valve 8 becomes positive pressure, but the check valve 4
0 performs its function and prevents positive pressure from flowing into the negative pressure chamber 22, so the negative pressure chamber 22 never becomes positive pressure. At this time, since the pressing force of the spring 36 alone does not generate enough pressing force to reverse the bead 30a of the diaphragm 30 toward the atmospheric chamber 24, the reversal of the bead 30a of the diaphragm 30 can be prevented. Also, at this time, the negative pressure chamber 22
The negative pressure remaining in the air cleaner 14 flows out through the bypass passage 42. At that time, since the negative pressure passes through the constricted part 44 of the bypass passage 42, this constricted part 4
4 prevents a sudden movement of the negative pressure, and prevents a sudden change in the negative pressure within the negative pressure chamber 22. Therefore, no excessive pressure is applied to the diaphragm 30 of the negative pressure chamber 22.

As is clear from the above detailed explanation, according to the configuration of this invention, during natural air supply, the negative pressure chamber of the EGR control valve communicates with the intake system, and the negative pressure generated in the intake system is utilized. Not only does this enable the control function of the EGR control valve to be fully utilized, but also during supercharging,
The check valve prevents the positive pressure generated in the intake system from flowing into the negative pressure chamber of the EGR control valve, thereby preventing the negative pressure chamber from becoming positive pressure. This can reliably prevent the bead of the diaphragm in the negative pressure chamber from being reversed by positive pressure, and therefore the control function of the EGR control valve caused by the bead of the diaphragm being reversed. It is possible to prevent a decrease in Moreover, since you only need to simply install the check valve,
It is structurally simple and the equipment used in conventional EGR systems can be used as is, for example.
There is no need to provide any special improvement equipment to the EGR control valve. Furthermore, since the negative pressure accumulated in the negative pressure chamber can be released to the outside via the bypass passage, it is possible to prevent the negative pressure in the negative pressure chamber from becoming higher than necessary. Since a constriction part is provided in the valve, it is possible to avoid sudden fluctuations in the negative pressure in the negative pressure chamber, and there is no risk of adversely affecting the control function of the EGR control valve, resulting in extremely practical and beneficial effects. It is something.

Note that the device of this invention can also be used as is for the EFI method.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of this invention, and is an overall schematic system diagram. FIGS. 2A and 2B are explanatory diagrams showing the inversion of a conventional diaphragm. In the figure, 2 is a turbocharger, 4 is a carburetor, and 6 is a turbocharger.
is a surge tank, 8 is a throttle valve, 10 is a negative pressure intake port, 12 is an intake passage, 14 is an air cleaner, 16 is a combustion chamber, 18 is a reflux discharge port, 20 is a
EGR control valve, 22 is negative pressure chamber, 24
26 is an atmospheric chamber, 26 is a valve chamber, 28 is a retention chamber, 30 is a diaphragm, 30a is a bead, 32 is a valve, 3
4 is a communication port, 36 is a spring, 38 is a negative pressure passage, 40
42 is a check valve, 42 is a bypass passage, 44 is a throttle portion, 46 is an exhaust passage, 48 is a catalyst device, 50 is a circulation passage, and 52 is a recirculation passage.

Claims (1)

[Scope of utility model registration request] In an EGR device having an EGR control valve used in a supercharged internal combustion engine, a negative pressure intake port is provided in the intake system, and the negative pressure intake port and the EGR
A check valve that prevents positive pressure from the intake system from flowing into the negative pressure chamber is provided in the middle of the negative pressure passage that communicates with the negative pressure chamber of the control valve, and a bypass that communicates with the upstream side of the turbocharger. An EGR device for a supercharged internal combustion engine, characterized in that a passage is provided as a branched negative pressure passage between the negative pressure chamber and the check valve, and a throttle part is provided in the middle of the bypass passage.