JPH0213702Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The invention relates to an exhaust system for a multi-cylinder engine.
In particular, the present invention relates to an exhaust system for a multi-cylinder engine mounted on an agricultural working machine such as a tractor.

《Prior art》 Since agricultural machinery such as tractors is used in a dusty atmosphere, multi-cylinder engines installed in agricultural machinery are equipped with a muffler cover that covers the outer circumference of the muffler, and a dustproof plate on the top of the exhaust manifold. This prevents dust from accumulating on the hot parts of the exhaust manifold or muffler and causing a fire.

[Problem to be solved] Conventional dustproof plates are placed to cover the top of the manifold, but if the dustproof plate is not placed with a gap between it and the top of the exhaust manifold, the dust will burn out. Since it is not possible to prevent this, a gap is created between the dustproof plate and the exhaust manifold. As a result, there is a problem in that dust enters and accumulates in the gap between the dustproof plate and the exhaust manifold, and the accumulated dust burns out. In addition, the dustproof plate is heated by radiant heat from the exhaust manifold,
In some cases, the dust that had accumulated on the top surface of the dustproof plate would burst into flames.

<Means for solving the problem> The present invention is designed to prevent dust from burning out at the exhaust manifold, and for this purpose, the dustproof plate placed above the exhaust manifold is shaped into a semi-cylindrical shape. By forming the dustproof plate, the upper half of the exhaust manifold is covered at regular intervals, and the ventilation holes provided in a part of the dustproof plate are communicated with the air intake ports of the muffler cover that covers the outer periphery of the muffler. It is characterized by this.

<Operation> In this invention, the dustproof plate placed above the exhaust manifold is formed into a semi-cylindrical shape, so that the dustproof plate extends over the upper half of the exhaust manifold at regular intervals and covers it. The provided ventilation port is connected to the intake port of the cooling air suction type muffler cover that covers the outer periphery of the muffler, so the muffler cooling air flows inside the muffler cover due to the ejector action of the jet force of the exhaust gas discharged from the muffler. will flow between the dustproof plate and the exhaust manifold and be taken into the muffler cover. As a result, even if dust may flow between the exhaust manifold and the dustproof plate, the dust will be carried by the cooling air flowing inside the muffler cover and emitted outside the muffler cover, causing the dust to flow into the exhaust manifold. This will prevent dust from accumulating on top and causing dust to burn out. Furthermore, since the exhaust manifold is also cooled by the cooling air taken into the muffler cover, the noise reduction effect of the exhaust system is enhanced, and the back pressure in the cylinder chamber is also reduced.

<<Example>> FIG. 1 is a partially cutaway front view showing an exhaust system of a multi-cylinder engine, and FIG. 2 is a perspective view taken out of the exhaust manifold.

In the figure, E indicates a three-cylinder vertical diesel engine, and a muffler connection pipe 3 is led out from the upper surface of an exhaust manifold 2 connected to an exhaust port 1 of this engine E. A cigar-shaped muffler 4 is vertically connected to the muffler connecting pipe 3.

A muffler cover 5 is fitted around the outer periphery of the muffler 4, and an exhaust outlet 7 of the muffler 4 opens in a ventilate portion 6 formed near the upper end of the inner peripheral surface of the muffler cover 5. Also, muffler cover 5
Both upper and lower ends are open, and the lower end opening is formed as an intake port 8 for muffler cooling air, and the upper end opening is formed as an exhaust port 9 for muffler cooling air. Therefore, due to the ejector action caused by the gas pressure of the exhaust gas ejected from the exhaust outlet 7 of the muffler 4, the muffler cooling air taken in from the air intake port 8 flows between the outer circumferential surface of the muffler 4 and the inner circumferential surface of the muffler cover 5. The muffler is cooled as it rises between the exhaust gases, and the mixture is mixed with exhaust gas and discharged to the outside from the exhaust outlet 7.

On the other hand, the exhaust manifold 2 has a dustproof plate 10 formed in a state in which the upper half of the circumferential surface is folded down.
A connecting pipe 11 that covers the outer periphery of the muffler connecting pipe 3 protrudes from the dustproof plate 10. The upper end of this connecting pipe 11 is configured to be able to be fitted onto the lower end of the muffler cover 5, and is configured to fix the dustproof plate 10 to the muffler cover 5 via the connecting pipe 11 with a tightening band 12. There is. The lower end of the connecting pipe 11 is opened so as to communicate with the gap 13 between the dustproof plate 10 and the manifold 2, and the lower end opening serves as a vent 14 for muffler cooling air.

Therefore, the muffler cooling air sucked in by the jet force of the exhaust gas discharged from the exhaust outlet 7 of the muffler 4 is
The air passes between the dustproof plate 10 and the exhaust manifold 2 and flows from the ventilation port 14 into the air intake port 8 opened at the lower end of the muffler cover 5. Therefore, the muffler cooling air cools the exhaust manifold 2 while passing through the gap 13 between the dustproof plate 10 and the exhaust manifold 2. Further, the dust that has entered the gap 13 between the dustproof plate 10 and the exhaust manifold 2 is discharged to the outside of the machine from the exhaust port 8 by the muffler cooling air that passes through the gap 13 and the inside of the muffler cover 5.

《Effects》 The present invention uses a multi-cylinder engine in which the outer periphery of the muffler is covered with a suction-type muffler cover, the circumferential surface of the exhaust manifold is covered with a dustproof plate, and the ventilation hole formed in a part of the dustproof plate is used in the muffler cover. Since it communicates with the air intake port, the muffler cooling air passes between the exhaust manifold and the dustproof plate and is taken into the muffler cover. As a result, even if dust gets between the exhaust manifold and the dustproof plate, the dust will be carried by the muffler cooling air and released from the exhaust port of the muffler cover, so the dust will accumulate on the manifold. There's nothing left to do,
There will be no more dust burning.

In addition, the muffler cooling air taken into the muffler cover will flow between the exhaust manifold and the dustproof plate, so the dustproof plate will also be cooled by the cooling air, and the dust accumulated on the dustproof plate will be removed. There will be no burning out.

Furthermore, since the exhaust manifold is cooled by the cooling air flowing between the exhaust manifold and the dustproof plate, the exhaust gas coming out of the exhaust port is rapidly cooled down within the exhaust manifold, resulting in a sound-reducing effect as an exhaust system. In addition, the back pressure to the combustion chamber can be reduced, and the combustion efficiency of the engine can be increased.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing the exhaust system of a multi-cylinder engine, and FIG. 2 is a perspective view taken out of the exhaust manifold. 2...exhaust manifold, 4...muffler, 5...
...muffler cover, 7...exhaust outlet, 8...air intake port, 9...exhaust port, 10...dustproof plate, 14...ventilation port, E...engine.

Claims (1)

[Scope of claim for utility model registration] Muffler 4 on exhaust manifold 2 of engine E
The muffler 4 is covered with a suction type muffler cover 5, and an air intake port 8 is provided at the bottom of the muffler cover 5, and an air exhaust port 9 is provided at the top of the muffler cover 5.
is provided, and by the ejecting action of the exhaust gas flowing out from the exhaust outlet 7 formed at the upper end of the muffler 4, the muffler cooling air is transferred from the air intake port 8 of the muffler cover 5 to the air exhaust port 9.
Exhaust manifold 2
In the exhaust system for a multi-cylinder engine whose upper surface is covered with a dustproof plate 10, by forming the dustproof plate 10 into a semi-cylindrical shape,
The dustproof plate 10 covers the upper half of the exhaust manifold 2 at regular intervals, and the ventilation holes 14 provided in a part of the dustproof plate 10 are communicated with the air intake ports 8 of the muffler cover 5. cylinder engine exhaust system.