JPH0310375Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a preheating device for an intake manifold.
In particular, the present invention relates to an intake manifold preheating device that can protect a carburetor from heat damage and improve operational performance such as restartability of an internal combustion engine.

[Prior Art] In the intake system of an internal combustion engine, it is desirable to completely atomize fuel and distribute it uniformly to each cylinder to maintain good operating conditions of the internal combustion engine. However, especially when starting at a low temperature, the internal combustion engine is in a cold state and only a small amount of fuel is supplied, which can easily cause engine malfunction. Therefore, in order to promote atomization of the fuel, a cooling water passage is provided in the intake manifold to heat the intake manifold to the temperature of the cooling water. In addition, in recent years, due to the increase in the output of internal combustion engines and the installation of air conditioners, it has become extremely difficult to maintain thermal performance over a period of time. Therefore, when the outside air temperature is high, there is a risk that the engine will malfunction or the vehicle components will overheat.

[Problems to be solved by the invention] By the way, as shown in FIGS. 3 and 4, in the conventional intake manifold 2, the main cooling water passage 18 communicating with the cooling water passage 16 extends to the side of the carburetor mounting flange 8. It has been extended. When the internal combustion engine is stopped after driving under severe driving conditions with high engine load, such as when driving uphill, the surface temperature of the intake manifold 2 and the air temperature in the intake passage become approximately the same as the cooling water temperature. Further, the carburetor is attached to the end face of the carburetor attachment flange 8 of the intake manifold 2 via a heat insulating member.

However, the temperature of the carburetor body is affected by various factors such as the ambient temperature of the carburetor, the surface temperature of the intake manifold 2, the temperature of the air flowing through the intake passage of the intake manifold 2, and the temperature of the fuel from the fuel tank. It is something. The carburetor is insulated and the temperature of the fuel, e.g. gasoline, in the float chamber of the carburetor is 60℃.
At this point, approximately 20% of the gasoline is vaporized, and this vaporized fuel flows into the intake passage. For this reason,
The air-fuel ratio fluctuated greatly toward the rich side, causing problems such as restart failure and other engine malfunctions.

[Purpose of the invention] Therefore, in order to eliminate the above-mentioned disadvantages, the purpose of this invention is to divide the intake manifold into an intake manifold on the carburetor side and a manifold on the cylinder side, and to provide a cooling water passage in the intake manifold on the carburetor side. A cooling water passage is formed in the intake manifold on the cylinder head side, and a cooling water passage is formed in the intake manifold on the cylinder head side by interposing a heat insulating member between the intake manifold on the carburetor side and the intake manifold on the cylinder head side. The heat from the engine promotes atomization of the fuel, and protects the carburetor from heat damage by preventing the temperature of the intake manifold on the carburetor side from rising, preventing overheating of the carburetor and causing engine malfunction. An object of the present invention is to provide a preheating device for an intake manifold that can prevent such problems and improve operational performance such as restarting an internal combustion engine.

[Means for solving the problem] In order to achieve this object, this invention divides the intake manifold provided between the carburetor and the cylinder head into an intake manifold on the carburetor side and an intake manifold on the cylinder head side. , a cooling water passage is not formed in the intake manifold on the carburetor side, but a cooling water passage is formed in the intake manifold on the cylinder head side, and a heat insulating member is interposed between the intake manifold on the carburetor side and the intake manifold on the cylinder head side. It is characterized by what it did.

[Function] According to the configuration of this invention, the air-fuel mixture in the intake manifold on the cylinder head side is actively atomized by the heat of the cooling water flowing through the cooling water passage.

In addition, the carburetor is separated from the cylinder head, which is the heat source side, and the heat of the intake manifold on the cylinder head side is blocked by the heat insulating member, and the radiant heat from the intake manifold is reduced. This prevents heat transfer to the carburetor, causing the carburetor to overheat and vaporize the fuel in the carburetor float chamber.
Prevents the air-fuel ratio from becoming rich. As a result,
It is possible to improve operational performance such as restartability of the internal combustion engine.

[Example] Hereinafter, an example of this invention will be described in detail and specifically based on the drawings.

1 and 2 show an embodiment of this invention. In the figure, 2 is an intake manifold.
Although not shown, the intake manifold 2 is provided between the carburetor and the cylinder head, and introduces the air-fuel mixture produced by the carburetor into each cylinder.

The intake manifold 2 is divided into a carburetor side intake manifold 4 and a cylinder head side intake manifold 6.

The carburetor side intake manifold 4 is formed with a carburetor mounting flange 8 for mounting the carburetor and a carburetor side connecting portion 10 for sandwiching a heat insulating member 22, which will be described later. A heat insulating member (not shown) is interposed between the end face of the carburetor mounting flange 8 and the carburetor.

Further, the cylinder head side intake manifold 6 is formed with a cylinder head side connection part 12 to be joined to the carburetor side connection part 10 and a cylinder head attachment flange 14 for attachment to the cylinder head.

In addition, the cylinder head side intake manifold 6 is formed with cooling water passages 16, 16 that communicate with a cooling water passage (not shown) of the cylinder head, and a main cooling water passage that communicates with these cooling water passages 16, 16. A water passage 18 is formed. This main cooling water passage 18 is provided with a thermostat mounting portion 20 for a thermostat that adjusts the cooling water temperature to a constant temperature.

However, in the carburetor side intake manifold 4, the first
As shown in the figure, no cooling water passage is formed.

A heat insulating member 22 is interposed between the carburetor side intake manifold 4 and the cylinder head side intake manifold 6, and the carburetor side connection portion 10 and the cylinder head side connection portion 12 are connected to each other by a plurality of fittings 24 such as bolts and nuts. It has been concluded by.

The heat insulating member 22 has the function of sealing the joint between the carburetor side intake manifold 4 and the cylinder head side intake manifold 6, and also has the function of blocking conduction heat from the cylinder head side intake manifold 6, which is the heat source side.

Next, the operation of this embodiment will be explained.

Cooling water heated by engine heat flows into the cooling water passage 16 and main cooling water passage 18 formed in the cylinder head side intake manifold 6, and the cylinder head side intake manifold 6 is overheated by this cooling water. As a result, vaporization of the air-fuel mixture in the cylinder head side intake manifold 6 is promoted.

By the way, according to this embodiment, the cooling water passage 1
6 is formed only in the intake manifold 6 on the cylinder head side, so the temperature of the intake manifold 4 on the carburetor side does not rise, and therefore the carburetor is provided in a state separated from the heat source side.

In addition, the heat in the intake manifold 6 on the cylinder head side is blocked by the heat insulating member 22, thereby preventing heat from being conducted to the carburetor side.

Furthermore, the radiant heat of the intake manifold 6 on the cylinder head side can be reduced. Therefore, the atmospheric temperature of the carburetor, the surface temperature of the intake manifold 4 on the carburetor side, the temperature of the air flowing through the intake passage of the intake manifold 4 on the carburetor side are prevented from rising, and heat transfer to the carburetor is minimized. can be lowered and protect the vaporizer from heat damage.

As a result, overheating of the carburetor is prevented, fuel is prevented from being vaporized in the float chamber of the carburetor, and the air-fuel ratio is maintained appropriately to prevent engine malfunction.

This improves restart of the internal combustion engine and improves other driving performance.

[Effects of the invention] As is clear from the above detailed explanation, according to this invention, the intake manifold is divided into an intake manifold on the carburetor side and an intake manifold on the cylinder head side, and cooling water is supplied to the intake manifold on the carburetor side. A cooling water passage is formed in the intake manifold on the cylinder head side without forming a passage, and a cooling water passage is formed on the cylinder head side by interposing a heat insulating member between the intake manifold on the carburetor side and the intake manifold on the cylinder head side. The heat of the intake manifold promotes fuel atomization, prevents the temperature of the intake manifold on the carburetor side from increasing, and blocks the conduction heat from the intake manifold on the cylinder head side, which is the heat source side. It is possible to prevent the generation of radiant heat as much as possible, protect the carburetor from heat damage, and improve operating performance such as restartability.

[Brief explanation of drawings]

1 and 2 show an embodiment of this invention, with FIG. 1 being a schematic view of the intake manifold, and FIG. 2 being an end view as indicated by the arrows in FIG. FIG. 3 is a schematic view of a conventional intake manifold, and FIG. 4 is an end view shown by the arrow in FIG. In the figure, 2 is the intake manifold, 4 is the carburetor side intake manifold, 6 is the cylinder head side intake manifold, 10 is the carburetor side connection part, 12 is the cylinder head side connection part, 16 is the cooling water passage, and 18 is the main cooling a water passage, and 22 is a heat insulating member.

Claims (1)

[Scope of utility model registration request] The intake manifold provided between the carburetor and the cylinder head is divided into an intake manifold on the carburetor side and an intake manifold on the cylinder head side, and a cooling water passage is not formed in the intake manifold on the carburetor side and the intake manifold on the cylinder head side A preheating device for an intake manifold, characterized in that a cooling water passage is formed in the intake manifold, and a heat insulating member is interposed between the intake manifold on the carburetor side and the intake manifold on the cylinder head side.