JPH037553Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

The present invention relates to a blockage prevention device for an EGR passage in an EGR device for purifying exhaust gas of a vehicle engine, and particularly to a device for preventing blockage by using auxiliary air of an idle correction device.

[Conventional technology]

In vehicle engines, especially NOx in exhaust gas
In order to reduce this, an EGR device is installed in which an EGR passage with an EGR valve is connected from the exhaust port to the intake manifold of the intake system, and a portion of the exhaust gas is recirculated to the intake system by controlling the flow rate with the EGR valve. It's getting old. By the way, the above-mentioned exhaust gas contains various products of combustion, unburned carbon, etc., and these are released into thin particles during the EGR action.
It adheres to the inner wall of the EGR passage and after long-term use.
There is a risk of clogging in the EGR passage. For this reason, it is desirable to regularly ventilate the EGR passage to prevent clogging without impairing engine operating performance. Therefore, regarding prevention of clogging in this type of EGR device, there is a prior art, for example, in Japanese Patent Application Laid-Open No. 13724/1983, which prevents the air passage from the air cleaner from being blocked.
A method has been proposed in which the EGR passage is connected to the upstream side of the EGR valve to constantly mix outside air into the recirculating exhaust gas to cool it and prevent the accumulation of combustion products.

[Problem that the idea aims to solve]

However, with this method, air is constantly supplied from the EGR device, and it is necessary to set the fuel system of the carburetor to a high level, which also causes problems.
Since the amount of air as well as the amount of EGR varies depending on the operating condition of the engine, the above setting becomes extremely complicated. Furthermore, since the cooling effect of the exhaust gas varies depending on the outside temperature and the amount of air changes, there is a problem that a constant clogging prevention effect cannot be expected. In view of these problems in the conventional technology, the present invention has been developed to improve the EGR passage by changing the setting of the carburetor fuel system and periodically scavenging the EGR passage without being affected by outside temperature, etc. In other words, the purpose is to provide a prevention device.

[Means to solve the problem]

In order to achieve its purpose, the clogging prevention device of the present invention uses an EGR valve whose opening area changes by detecting the temperature of the engine body and the negative pressure near the carburetor throttle valve.
An EGR device equipped with an EGR passage, an air valve for introducing atmospheric air that opens and closes according to changes in intake air temperature, and one end of which is connected to the
An idle correction device is provided that includes an air passage that opens into the EGR passage on the downstream side of the EGR valve and whose other end is connected to the air valve, and when the intake air is at a high temperature, the air valve opens and the air passage opens. downstream via
It is characterized in that air from the air valve is sent into the EGR passage.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. In the drawings, numeral 1 is the engine body;
An air cleaner 2 is installed in the intake system of this engine body 1.
The carburetor 3 and the intake manifold 4 are configured to communicate with each other,
Such an engine is provided with an EGR device 5 and an idle correction device 6. The EGR device 5 is located between the exhaust port 7 of the engine body 1 and the supply port 8 of the intake manifold 4.
The EGR passage 9 communicates with the EGR passage 9.
A valve 10 is provided, and a negative pressure chamber 11 of the EGR valve 10 communicates with the air cleaner 2 through a passage 12 and a negative pressure outlet port 13 of the carburetor 3 and a thermo valve 14 . The opening degree of the EGR valve 10 is changed by the negative pressure of the negative pressure outlet port 13 according to the engine operating state and the operation of the thermo valve 14 according to the warm-up state of the engine, and the flow rate is thereby controlled and the exhaust gas is A portion of the intake air flows back through the EGR passage 9 to the intake manifold 4. In addition, since the intake manifold 4 is bifurcated and communicates with the left and right banks of the engine body 1, the supply holes 15 after the supply port 8 are also bifurcated and the exhaust gas is distributed equally between the left and right banks. It is configured to be distributed. In the idle correction device 6, an air valve 16 is provided in the air cleaner 2, which opens due to deformation of a bimetal during high temperatures such as in summer, and an air passage 17 bypasses the carburetor 3 and communicates with the downstream side of the air valve 16. The air passage 17 is provided with an orifice 18 that determines the flow rate. During high temperatures in the summer, the air valve 16 opens to replenish air, especially during idling operation when the slot valve is almost fully closed, resulting in over-enrichment of the mixture air-fuel ratio due to fuel leaking from the fuel system of the carburetor 3. It is now possible to prevent Therefore, as a device to prevent clogging of the EGR passage,
The air passage 17 of the idle correction device 6' is
The EGR passage 9 is communicated with the EGR valve 10 downstream. With the above configuration, when the air valve 16 opens at a high temperature, auxiliary air passes through the air passage 17 to the EGR passage 9.
It flows into the intake manifold 4 via the EGR passage 9 and supply hole 15. Therefore, when the EGR valve 10 is closed during idling, only the auxiliary air passes through the EGR passage 9 and the supply hole 15 to perform scavenging, and is evenly distributed to the left and right banks of the intake manifold 4 by the supply hole 15. and mixed into fuel. Then, during load operation, EGR
When the valve 10 is opened and exhaust gas is recirculated, auxiliary air is mixed into the exhaust gas in the EGR passage 9, and scavenging and air-fuel ratio correction of the EGR passage 9 are performed in the same manner as described above.

[Effect of the idea]

As is clear from the above explanation, according to the present invention, the auxiliary air of the idle correction device, which corrects the air-fuel ratio by replenishing air only during high temperatures such as summer, is used to prevent clogging by scavenging the EGR passage. Because of this structure, there is no need to change the setting of the fuel system of the carburetor, and the engine operating performance is not impaired at all. Since the air passages of the idle correction device do not need to be connected to the intake manifold or the like separately, the structure is simplified. Furthermore, since the fuel is replenished using the EGR system supply hole, correction can be made uniformly to the left and right banks, ensuring smooth idling operation.

[Brief explanation of drawings]

The drawing is a block diagram showing an embodiment of the device according to the present invention. 1...Engine body, 5...EGR device, 6...
...Idle correction device, 7...Exhaust port, 8...
Supply port, 9...EGR passage, 10...EGR valve, 1
6...Air valve, 17...Air passage.

Claims (1)

[Scope of utility model registration request] An EGR device includes an EGR valve and an EGR passage whose opening area changes by detecting the temperature of the engine body and the negative pressure near the carburetor throttle valve, and an air valve for introducing atmospheric air that opens and closes according to changes in intake air temperature. is the EGR
An idle correction device is provided that includes an air passage that opens into the EGR passage downstream of the valve and whose other end is connected to the air valve. above on the downstream side
A clogging prevention device for an EGR passage, characterized in that air from the air valve is sent into the EGR passage.