JPH0540295Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to improvements in internal combustion engines for vehicles. More specifically, part or all of an exhaust path consisting of an exhaust manifold and an exhaust pipe is covered with a tubular body (usually called a heat protector), one end of which is open to the exhaust path, and the other end of which is an air cleaner. The present invention provides a device that eliminates problems that occur when water adheres to the exhaust path or accumulates in the tubular body in devices that open to the fresh air intake path.

[Prior art]

In a front-wheel drive vehicle, if the gasoline engine equipped with a carburetor is mounted horizontally and the exhaust path is located at the front of the vehicle, it will be difficult to drive if the exhaust path consisting of the exhaust manifold or exhaust pipe is exposed. The wind removes heat from the exhaust path, lowering the exhaust temperature, and the temperature of the exhaust gas before the catalyst provided at the rear of the exhaust path no longer reaches the activation temperature of this catalyst.

Therefore, a method is used in which the exhaust manifold and the exhaust path of the exhaust pipe are covered with a cover, that is, a heat protector, in order to maintain the exhaust temperature and reach the activation temperature of the catalyst. Also,
This cover is sometimes provided to prevent heat damage to peripheral equipment.

On the other hand, in the case of vehicles equipped with a carburetor, during cooling, warm air around the exhaust manifold is generally guided into the air cleaner to promote fuel atomization and improve drivability.

Technologies for controlling engine intake air temperature include:
For example, there is a technique described in Utility Model Application Publication No. 59-58764.
When the outside air temperature is low, this technology guides air warmed by the engine's exhaust manifold to the intake side, mixes it with fresh air, and controls the intake air temperature to a constant level. Efforts are being made to promote atomization. In addition, with this technology, when the outside air temperature is high, the intake of the heated air is stopped, but in this case, the heated air in the heated air supply passage is prevented from leaking into the fresh air supply passage, and the intake air is Prevents output from decreasing due to temperature rise.

Since the heated air supply passage guides the heated air around the exhaust manifold and the exhaust pipe to the fresh air supply passage as described above, one end thereof communicates with a cover that covers the exhaust manifold. The structure is such that

By the way, in a vehicle having such a structure, when the outside temperature is as low as 5° C. to 10° C. and the vehicle is driven on a humid day, for example, on a rainy day, the exhaust pipe is likely to get wet with water. Immediately after the engine is started, the temperature of the exhaust pipe does not rise that much, so water steadily adheres to the exhaust pipe and accumulates inside the tubular body.

On the other hand, the temperature of the exhaust pipe increases as time passes, as shown by curve A indicated by the two-dot chain line in the graph of FIG. As the temperature of the exhaust pipe increases, the water adhering to the exhaust pipe changes to water vapor in a short time period of, for example, 2 to 5 minutes, and a large amount of water vapor is eventually generated.

Since the cover of the exhaust path consisting of the exhaust pipe and the exhaust manifold plays the role of the introduction pipe, the large amount of water vapor generated within the cover is forcibly supplied into the carburetor. Part of this water vapor freezes due to the heat of vaporization of the fuel, becomes a shear bed, and accumulates around the throttle valve of the vaporizer. If this ice builds up further, it may eventually block the throttle valve and cause the engine to stop.

In addition, in the graph of Figure 5, as shown in curve B, the engine, which was running at 2300 rpm at the time of engine startup,
After 4 to 5 minutes have elapsed, a situation occurs in which the speed drops to 750 rpm due to the freezing effect of the water vapor and the engine stops.

In addition, the intake air dehumidifier for an internal combustion engine proposed in the device described in Utility Model Application Publication No. 58-167762 is a device in which a dehumidifier for removing moisture is provided in the intake device upstream of the carburetor. There are problems such as a decrease in air intake performance, the hassle of replacing the dehumidifier, and the fact that it is not cost effective.

Furthermore, the engine warm-up intake device proposed in Utility Model Application Publication No. 56-133953 has an exhaust system.
An opening is provided around the pipe that introduces the warm air from the manifold into the intake device upstream of the carburetor to allow the warm air to escape when the outside temperature is high, but no consideration was given to removing the moisture contained in the warm air. The problem is that it ends up absorbing moisture.

[Purpose of invention]

An object of the present invention is to provide an internal combustion engine that can prevent the carburetor from freezing and clogging, which is a drawback of the conventional internal combustion engine equipped with a carburetor.

[Summary of the idea]

To achieve the above object, the present invention provides an exhaust path that is connected to the front of the engine main body, bypasses the engine main body, extends horizontally to the rear, and is provided with a catalytic reactor. A tubular body covers the space between the tubular bodies, a heated air pipe opened inside the tubular body is opened to a fresh air suction path, and a plurality of holes for releasing water vapor are distributed on the upper surface of the horizontal part of the tubular body. This is a vehicle internal combustion engine.

The areas where water adheres and accumulates are often not in the vicinity of the exhaust manifold, but in the horizontal areas of the exhaust pipe and tubular body, and water vapor is likely to be generated in these areas. A feature of this invention is that a plurality of holes for releasing water vapor are distributed and arranged in places where it is difficult for water to enter while the vehicle is running, and where water vapor generated in the tubular body covering the exhaust route can easily be released. There is.

[Effect]

In the present invention with the above configuration, water vapor release holes are provided in a part of the tubular body (heat protector) that covers the exhaust path, so water may adhere to the exhaust pipe or accumulate inside the tubular body, and When it turns into water vapor, this water vapor undergoes rapid volume expansion during vaporization, so most of the water vapor escapes to the outside through the water vapor release hole provided in the tubular body and enters the vaporizer. Water vapor will be extremely low. As a result, a carburetor blockage accident due to the freezing phenomenon of water vapor caused by the heat of vaporization does not occur, and stable engine operation, that is, stable vehicle running can be achieved.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

Fig. 1 is a schematic diagram showing the main parts of an automobile incorporating a heat protector according to the present invention, Fig. 2 is a plan view showing a part of the heat protector, Fig. 3 is a sectional view, and Fig. Figure 2 -
It is a cross-sectional view along the war.

FIG. 1 is a schematic diagram showing the front part of an automobile incorporating an exhaust pipe heat protector according to the present invention.

An engine body (engine) 2 is disposed below the hood panel 1. An intake passage pipe 6, which incorporates a carburetor 5 consisting of a venturi 3, a throttle valve 4, etc., is connected to the intake side of the engine body 2. An air cleaner 7 is attached to the end of the intake passage pipe 6. Fresh air A is sucked in through an intake duct 8 opening in the air cleaner 7, and the filtered fresh air A is supplied to the engine body 2 through an intake path 9 formed by the intake passage pipe 6.

The intake duct 8 also includes a heated air supply pipe 10.
One end is connected to the exhaust manifold 1, and the other end is a part of the exhaust path of the engine body 2.
The exhaust manifold 11 is connected in communication with the tubular body 12 which is a cover covering the exhaust manifold 11.
The heated air outside the air cleaner 7 is guided to the air cleaner 7 side.

Further, in order to control the amount of heated air flowing into the air cleaner 7, the heated air supply pipe 10
An on-off valve 13 that is controlled to open and close is provided at the connection portion between the intake duct 8 and the air intake duct 8 . This on-off valve 13
The opening/closing operation is performed according to changes in the outside air temperature, and acts so that the air sent from the air cleaner 7 to the engine body 2 always has a constant temperature. As a result, the vaporization and atomization state in the carburetor 5 is always constant, so that the engine drive is stabilized.

On the other hand, an exhaust pipe 14 is connected to the exhaust manifold 11. This exhaust pipe 1
4 is bent in the middle and its tip extends toward the rear of the vehicle. Further, a catalytic reactor 15 is attached to this exhaust pipe 14. moreover,
A tubular body 16 that is a heat protector or cover is attached to the exhaust pipe 14.

The tubular body 16 plays a role of preventing heat damage to the surrounding area of the exhaust pipe 14, and also directs heated air around the exhaust pipe 14 to the heated air supply pipe 10.
It also serves as a guide to guide you.

In addition, some areas of this tubular body 16, for example,
In the area R shown in FIG. 1, a plurality of water vapor release holes 18 are provided in order to release water vapor 17 generated in the area surrounded by the exhaust pipe 14 and the tubular body 16 to the outside of the tubular body 16. ing. The water vapor release hole 18 is, as shown in FIGS. 2 to 4,
Due to the characteristics of the engine main body, the steam is distributed in the upper surface of the horizontal portion of the tubular body 16, where the most water vapor is generated when the rotation approaches the idling rotation during warm-up.

Depending on the size and distribution of the water vapor release holes 18, the heat dissipation becomes too high, and the tubular body 16 loses its original function as a heat damage prevention cover and heated air intake cover. Therefore, caution is required.

The tubular body 16 has a split structure, in which two cover bodies 19 and 20 each having a gutter structure are integrated into a cylindrical shape using bolts 21 and nuts 22.

In the tubular body 16 having such water vapor release holes 18, water droplets adhere to the outer peripheral wall of the exhaust pipe 14, and these water droplets release water vapor 1 as the temperature of the exhaust pipe 14 increases.
7, these water vapors 17 can be released to the outside of the tubular body 16 through the water vapor release holes 18. That is, the moisture adhering to the exhaust pipe 14 or the tubular body 16 begins to evaporate as the temperature of the exhaust pipe 14 begins to rise at the same time as the engine main body is started. The idling speed immediately after starting the engine is set high due to the characteristics of the engine, so even if water vapor gets mixed in, it will not be a problem.
In reality, when the rotation starts to drop, the water in the exhaust pipe 14 begins to evaporate. When this rotation starts to decrease, the opening degree of the throttle valve starts to decrease and the opening area becomes smaller, so water vapor 17 flows into the vaporizer 5.
When the water vapor 17 enters the engine, it freezes due to the heat of vaporization of the fuel and forms a shear bed, which tends to clog the throttle section whose opening area has become smaller, and eventually causes the engine itself to malfunction.

However, as mentioned above, even when the rotation has started to slow down, the water vapor 17 that undergoes rapid volumetric expansion generated between the exhaust pipe 14 and the tubular body 16 is released from each water vapor release hole 18 of the tubular body 16 to a large extent. The amount of water vapor 17 that escapes to the outside and reaches the inside of the carburetor 5 is extremely small, and does not reach the level of causing malfunction of the engine. Therefore, the vehicle can start and run smoothly even under conditions of low outside temperature and high humidity.

It goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the gist thereof.

[Effect of idea]

The internal combustion engine for a vehicle according to the present invention is connected to the front of an engine main body, bypasses the engine main body, and extends horizontally to the rear, and has a catalytic reactor installed between the engine main body and the catalytic reactor. is covered with a tubular body, a heated air pipe opened inside the tubular body is opened to a fresh air intake path, and a plurality of holes for discharging water vapor are distributed on the upper surface of the horizontal part of the tubular body. Therefore, the following effects are achieved.

(1) Even if the exhaust route is connected to the front of the engine body, bypasses the engine body, extends horizontally to the rear, and is provided with a catalytic reactor, which tends to reduce the exhaust temperature, the exhaust route may not connect to the engine body. By covering the space between the catalytic reactor and the tubular body, it is possible to maintain the exhaust gas temperature up to the catalytic reactor at the activation temperature of the catalyst and sufficiently remove air pollutants. By arranging multiple holes that release water vapor in a distributed manner, when the engine approaches idling speed during warm-up after starting and the temperature of the exhaust pipe rises, water vapor builds up on the exhaust path and tubular body. Even if the water changes to water vapor, most of the water vapor is instantly released from the water vapor release hole to the outside of the tubular body due to the volume expansion of water vapor. Since the vaporized gas does not become unstable due to a large amount of water vapor entering the vaporizer and freezing, it is possible to start and run stably even on rainy days.

(2) The tubular body has multiple holes for water vapor release distributed in a distributed manner, minimizing heat radiation and preventing it from occurring locally, so it has a sufficient heat shielding effect and can prevent heat damage to peripheral equipment. be effective.

(3) The tubular body shall have a plurality of water vapor release holes arranged in a distributed manner so as to minimize heat radiation, and the tubular body shall fully fulfill its role as a guide for guiding the heated air from the outer circumference of the exhaust pipe to the vaporizer. Therefore, by using this heated air, the fresh air introduced to the carburetor is always maintained at a constant temperature, which has the effect of stably driving the engine body.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the main parts of a vehicle internal combustion engine according to the present invention, FIG. 2 is a plan view showing a part of a tubular body that protects the exhaust route, and FIG. 3 is a sectional view,
Figure 4 is also a sectional view along the - line of Figure 2,
FIG. 5 is a graph showing changes in engine speed and temperature over time. 2...Engine body, 5...Carburizer, 6...Intake passage pipe, 7...Air cleaner, 9...Intake passage,
DESCRIPTION OF SYMBOLS 10...Heated air supply pipe, 11...Exhaust manifold, 12...Cover, 14...Exhaust pipe, 16...Tubular body, 17...Water vapor, 18...
...Vapor release hole.

Claims (1)

[Scope of utility model registration request] A tubular body that is connected to the front of the engine body, bypasses the engine body, extends horizontally to the rear, and covers the space between the engine body and the catalytic reactor in an exhaust path provided with a catalytic reactor, and the tubular body A vehicular internal combustion engine comprising: a heated air pipe opening into a fresh air intake path; and a plurality of holes for discharging water vapor distributed on the upper surface of a horizontal portion of the tubular body.