JPS6250660B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an engine intake system, more specifically, an engine equipped with an exhaust gas recirculation (hereinafter abbreviated as "EGR") system, which prevents the deposition of deposits caused by EGR gas. This relates to an engine intake system.

EGR devices have become widely used to reduce NOx in exhaust gas. This EGR device injects a portion of the exhaust gas into the combustion chamber of the engine through the intake system and re-burns it.
EGR gas contains carbon particles and lead compounds, and after an engine has been operated for a long period of time, these gases are deposited into various parts of the EGR system and intake system (intake manifold, carburetor, etc.). Conventionally, there has been a problem that these substances adhere to each other and interfere with the functions of these devices. When a large amount of deposits accumulate on these devices, it becomes impossible to accurately control the flow rates of air, fuel, and EGR gas, resulting in problems such as the engine not being able to operate smoothly and fuel consumption increasing. Such problems can occur when special operating conditions are continued for an extremely long period of time, but until now, the true cause of deposits has not been accurately understood, so it has not been possible to effectively There was no way to prevent deposits from accumulating.
The inventors discovered that the contents of EGR gas are
We experimentally investigated the cause of adhesion to EGR equipment. According to this, the blowby gas supplied from the engine's blowby gas circulation system to the intake system
It has been found that when EGR gas is mixed in the intake passage, deposits tend to accumulate, although the reason is not clear.

Therefore, the purpose of the present invention is to
By making it difficult for EGR gas to mix with the intake system, the substances contained in the EGR gas can
An object of the present invention is to provide an air intake device that prevents adhesion to an EGR device and allows the EGR device to maintain proper EGR flow control over a long period of time.

In the present invention, an engine intake system is divided into two passages through which intake air flows by using a partition wall, and EGR gas is supplied to one of the passages, and blow-by gas is supplied to the other.
This made it difficult for the gas to mix with the air intake device.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The carburetor 1 has a first intake passage 2 and a second intake passage 3.
The first and second throttle valves 4 and 5 are rotatably installed in both passages, respectively. Between the carburetor 1 and the intake valve 11 facing the combustion chamber 10, there are provided a heat insulating plate 6, an intake manifold 7, an intake port 8, and a gasket (not shown) provided between each of these as necessary. An intake pipe 12 consisting of the like is interposed. Instead of this, the heat insulating plate 6 may be a mere spacer without heat insulating properties, or may be only a gasket.

A partition wall 13 is provided in all or at least the upstream side of the intake pipe 12 (that is, the side near the carburetor 1), thereby dividing the passage in the intake pipe into a first intake pipe passage 14 and a second intake pipe passage 15. Separate. These first and second intake pipe passages 14 and 15 communicate with the first and second intake passages 2 and 3, respectively.

An EGR gas supply port 16 for supplying EGR gas from an EGR device (not shown) is opened to either the first intake passage 2 or the first intake pipe passage 14,
On the other hand, the blowby gas supply port 17 that supplies blowby gas from a blowby gas circulation device (not shown) is connected to the second intake passage 3 or the second intake pipe passage 1.
Open at 5. 18 is a cylinder block, 19
is a piston, and 20 is a valve stem guide.

Without the partition wall 13, the blowby gas flowing from the blowby gas supply port would reach the vicinity of the EGR gas supply port 16 due to fluid pulsation in the intake pipe 12, and further flow back from here to the EGR device and be mixed with the EGR gas. As a result, deposits are deposited on various parts of the EGR device, the EGR supply port 16, the vaporizer 1, and the like.

In the embodiment shown in FIG. 1, the partition wall 13 extends close to the intake valve 11 and divides the passage into two over almost the entire area of the intake pipe 12.
Gas and blow-by gas are almost completely separated. In the embodiment shown in FIG. 2, the partition wall 13' is limited to the intake manifold, but it has been confirmed that this is sufficient to achieve the purpose. Also the third
In the embodiment shown in the figure, the cylindrical partition wall 13'' is fixed to the heat insulating plate 6, but the blow-by gas supply port 17 is on the upstream side of the flow, that is, on the second
If the intake passage 15 or the heat insulating plate 6 is opened, such an arrangement can also considerably prevent the accumulation of deposits. The embodiment shown in FIG. 3 has the advantage that it is easy to use even if the engine is already installed because there is no need to change the intake manifold.

In the present invention, since the partition walls 13, 13', and 13'' are provided, mixing of EGR gas and blow-by gas does not occur near the vaporizer 1 or the EGR supply port 16, making it difficult for deposits to accumulate. Even if deposits are deposited, the fuel, air or
Since deposits do not accumulate in areas that would interfere with EGR gas flow control, the engine's normal functioning will not be impaired. As a result, even if the engine is used for a long period of time, its driving performance and fuel consumption characteristics can be maintained favorably. Further, since the EGR gas and the blow-by gas are separately mixed with intake air and then flowed into the combustion chamber, these gases are sufficiently combusted.

Note that the present invention is directed to the low-load intake passage, that is, the first
The intake passages 2 and 14 and the high-load intake passage, that is, the second
An existing intake device including the intake passages 3 and 15 can be used as is, or a portion thereof (such as the shape of the partition wall) may be improved. In that case, no matter which side the blow-by gas or EGR gas is supplied to, the partition walls 13, 13', and 13'' prevent the two from mixing, so the same effect can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a first embodiment of the intake device of the present invention, FIG. 2 is a diagram showing another embodiment of the present invention, and FIG.
The figure shows still another embodiment of the present invention. 1... Carburetor, 2, 14... First intake (pipe) passage, 3, 15... Second intake (pipe) passage, 16...
EGR gas supply port, 17...Blow-by gas supply port.

Claims (1)

[Claims] 1 The engine intake system is connected to the bulkheads 13, 13', 1
3", it is separated into two passages through which intake air flows, and blow-by gas is introduced into one passage and EGR gas is introduced into the other passage, and the blow-by gas and EGR are separated.
An engine intake system that prevents gases from mixing in the intake passage.