JPS6034764Y2 - Exhaust recirculation control device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of an exhaust gas recirculation control device for an automobile engine.

As one means for preventing the generation of NOx contained in the exhaust gas of automobile engines, an exhaust gas recirculation (EGR) device as shown in Fig. 1 is known (Japanese Patent Laid-Open No. 52-7
6528).

In FIG. 1, a part of the exhaust gas passing through the exhaust manifold 5 is guided from the introduction hole 5a to the valve chamber 6c via the upstream EGR passage 6a.

7 is an EGR valve, and a diaphragm 7c operates against a spring 7b in response to the negative pressure generated near the throttle valve 3 introduced into the negative pressure chamber 7a, and as the negative pressure increases, the valve body 7d
is pulled up and the valve opens.

Note that this VC negative pressure takes a maximum value in the engine partial negative pressure region, and therefore the opening degree of the EGR valve 7 reaches its peak in terms of partial load.

Depending on the opening degree of this EGR valve 7, the exhaust gas A is
It flows into the GR passage 6b and flows out into the intake manifold 4 from the EGR gas outlet 8.

On the other hand, the air-fuel mixture B produced in the carburetor main body 1 has its flow rate controlled by the throttle valve 3, and passes through the air passage 2 to the intake manifold 4.
Then, it mixes with the exhaust gas A and is sucked into a combustion chamber (not shown).

However, this recirculated exhaust gas (EGR gas) A contains water vapor generated by combustion, and since the EGR passages 6a and 6b are at a low temperature, this moisture tends to condense and adhere to the inner wall 6d of the passage.

In particular, since the wall surface temperature near the EGR gas outlet 8 provided in the intake manifold 4 is the lowest, the water contained in the EGR gas A is easily cooled and condensed and liquefied.

On the other hand, this EGR gas A also contains fine particles such as carbon and zinc produced by combustion.

These adhere to the above-mentioned condensed water, and a part of it solidifies to form a deposit.

If you continue to drive for a long time with this condition left unattended, EGR
Deposits accumulate intensively near the gas outlet 8, and the flow of EGR gas A is eventually obstructed, making proper EGR control impossible.

The present invention was developed by focusing on these conventional problems, and the blow-by gas ejection port from the crankcase is placed near the center of the EGR gas outlet, thereby reducing the blow-by gas ejection force and gas flow. The present invention provides an exhaust gas recirculation control device that removes deposits accumulated in the vicinity of an EGR gas outlet due to contained fuel.

Hereinafter, embodiments of the present invention will be described based on the drawings.

In FIG. 2, the EGR passage 6 is passed through the earthen wall of the intake manifold 4 and bent at a right angle near the EGR gas outlet 8a.

Opposed to the EGR gas outlet 8a, a blow-by gas outlet 10 is provided on the ceiling wall surface of the intake manifold 4.
to open.

A control valve 9 is provided at the blow-by gas outlet 10.
The control valve 9 is provided with a needle valve 12 and a return spring 11.

Therefore, the blow-by gas C blows through the EGR passage 6, joins with the EGR gas A near the blow-off port 8a, and the EGR
The gas is ejected into the intake manifold 4 from the gas outlet 8a.

As mentioned earlier, EGR gas A contains a small amount of moisture and fine particles, which tend to condense and adhere to the low-temperature outlet 8a, but these moisture and fine particles are removed by the jet of blow-by gas C. Since it is blown away, it becomes difficult to condense near the outlet 8a.

Furthermore, some of the attached fine particles are washed away by the unburned gas (gasoline) contained in the blow-by gas C, and their deposition is suppressed.

In this way, the air outlet 8a is cleaned and deposits are prevented from accumulating, making it possible to accurately control the amount of EGR and effectively reducing NOx without reducing engine output unnecessarily. It becomes possible.

As shown in Figure 3, the maximum flow rate of blow-by gas C is about 1710, which is the maximum flow rate of EGR gas, so E
The effect on GR can be ignored.

FIG. 4 shows another embodiment.

This is provided with an arc-shaped cover 13 having a large number of holes on the blow-by gas outlet 10, which further increases the flow rate of blow-by gas C and scatters it radially, thereby further enhancing the above effect. .

In the embodiment shown in FIG. 5, a trumpet-shaped guide tube 14 is provided to prevent the blow-by gas C from scattering and to make the ejection force of the blow-by gas C efficiently act on the EGR gas A.

Thereby, the cleaning action can be further improved.

As described above, in the present invention, a blow-by gas outlet is provided at the EGR gas outlet, and a blow-by gas control valve is provided near this outlet so that the blow-by gas is ejected in the same direction as the EGR gas. The ejection force and cleaning action of blow-by gas can prevent deposits from accumulating near the EGR ejection port, thus ensuring proper EGR at all times.
Based on GR control (NOx reduction can be achieved).

[Brief explanation of drawings]

Fig. 1 is a sectional view of the main part of a conventional EGR device, Fig. 2 is a sectional view of the main part of the present invention, Fig. 3 is a graph of blow-by gas flow rate, and Figs. 4 and 5 are each of other embodiments. FIG. 1... Carburetor body, 2... Carburetor air passage, 3... Throttle valve, 4... Intake manifold, 5... Exhaust manifold, 6...
・-EGR passage, 6a...Upstream EGR passage, 6
b...Downstream EGR passage, 6c...Valve chamber, 7...EGR valve, 8...E
GR gas outlet, 9...control valve,
10... Spout, 13... Cover 1
4...Guide plate.

Claims (1)

[Scope of utility model registration request] In an automobile engine that has an exhaust recirculation passage that recirculates part of the exhaust gas to the intake passage, and a blow-by passage that recirculates gas, the air vent in the crankcase is connected to the intake passage. An exhaust gas recirculation control device characterized in that a blow-by gas outlet is provided in the vicinity, and a blow-by gas control valve is provided in the vicinity of the blow-by gas outlet so that the blow-by gas is ejected in the same direction as the recirculated exhaust flow.