JPH0240072A - Intake pipe in internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the drivability of an engine by forming an intake pipe with a plastic material, while containing an additive material with higher heat conductivity than that of the plastic material as a base material, in this plastic material. CONSTITUTION:When temperature in an engine 1 goes up, this engine temperature is transmitted to an intake pipe 8 in a short time, making temperature in this pipe 8 go up, so that fuel flowing in the intake pipe 8 is heated and it is atomized so efficiently on an inner wall of the intake pipe 8, whereby mixture between air and fuel is made better, improving combustibility in the engine, so that improvement in engine performance is well promoted. On the other hand, heat conductivity to the intake pipe 8 grows larger whereby heat radiation to surroundings from the intake pipe 8 also becomes larger, and thereby such a possibility that temperature in the intake pipe 8 may largely go up is checked. Consequently, since temperature in a fuel supply system 2 being connected to the intake pipe 8 is also held down within a constant temperature rising range, vapor of fuel in a small diametral passage such as a fuel passage of a carburetor becomes hard to occur, so that a vapor-lock phenomenon in fuel is completely preventable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an intake pipe in an internal combustion engine that connects the internal combustion engine with a fuel supply device such as a carburetor or a fuel injection device.

[Conventional technology]

BACKGROUND ART Conventionally, an intake pipe integrally molded from polyamide resin or the like has often been used as an intake pipe that connects a fuel supply device and an internal combustion engine. This is achieved by taking advantage of the advantages of synthetic resin materials, such as their light weight, excellent corrosion resistance, and smooth intake pipe inner surface roughness. It is intended to provide an intake pipe that is excellent, lightweight, and has good intake efficiency.

[Problem to be solved by the invention]

However, although intake pipes made of synthetic resin materials have the above-mentioned excellent performance, they have the following problems because they have lower thermal conductivity than intake pipes made of metals such as aluminum and zinc.

By the way, the thermal conductivity of aluminum is 2.3 cal /see/ crn'/'O/cm
Thermal conductivity of polyamide resin: 0.4 can/sec/ crn'/'O/cm
■When starting the engine at a relatively low engine ambient temperature, the engine temperature rises as the engine continues to operate, but as mentioned above, the thermal conductivity of the synthetic resin material is low. Furthermore, the temperature of the intake pipe increases very slowly.

Therefore, the atomized fuel sucked into the intake pipe from the fuel supply system tends to adhere to the inner wall of the intake pipe, making it difficult to supply a highly vaporizable air-fuel mixture to the engine, making it difficult to improve the combustion performance of the engine. I can't hope.

(2) When the engine ambient temperature rises and the engine finishes warming up, the temperature of the intake pipe increases as the engine temperature has risen sufficiently. At this time, since the thermal conductivity of the intake pipe is low, it is difficult for heat to be radiated from the intake pipe to the surroundings, and the intake pipe is maintained at a high temperature state.

Although this improves the vaporization of the fuel in the intake pipe, there is a risk that the connection surface of the fuel supply device, such as a carburetor, connected to the intake pipe may be heated, increasing the temperature of the fuel supply device itself.

According to this, paper may be formed in the small diameter fuel passage provided in the fuel supply device, causing a paper lock phenomenon and interfering with proper fuel supply.

[Means for Solving the Problem] [Operation] The intake pipe for the internal combustion engine according to the present invention has been created in view of the above-mentioned problems, and combines the advantages of synthetic resin materials and the advantages of metal materials. In order to achieve the above purpose, the synthetic resin material used as the base material for forming the intake pipe has a thermal conductivity higher than that of the synthetic resin material as the base material. The intake pipe is formed by integrally containing an additive material having the following properties, and the intake pipe is formed from a synthetic resin material that has higher heat receiving and heat dissipating properties than synthetic resin materials.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. 1 is 4
2 is a fuel supply device such as a carburetor or a fuel injection device, and in this embodiment, the carburetor is shown.

An intake passage 3 passes through the inside of the carburetor, and a main nozzle 5 whose one end is submerged in a constant liquid level x-x in a float chamber 4 opens in a part of the venturi inside the intake passage 3, and a throttle valve 6 is opened and closed. By doing so, the amount of air supplied to the engine l and the intake passage 3 from the main nozzle 5 are
The amount of fuel drawn into the fuel tank is controlled to control the desired air-fuel mixture.

7 is an air cleaner for removing foreign matter in the air. The fuel supply system 2 and the engine l are connected through an intake pipe 8, and the fuel supply system 2 and the air cleaner 7 are connected through an air conduit 9. Then, when engine 1 is operated,
Fuel is sucked into the intake passage 3 of the fuel supply device 2, mixed with air flowing into the intake passage 3 from the air cleaner 7 and the air conduit 9, and this air-fuel mixture flows through the intake pipe 8 to the engine l.
supplied to

Here, the intake pipe 8 is formed as follows. That is, the intake pipe 8 is formed of a composite resin material having a resin material such as polyamide resin as a base material and containing powder or fibers such as aluminum in the base material.

According to this, the thermal conductivity of the intake pipe 8 is 0.4 ca/SeC/Crn'/
It is possible to obtain a high thermal conductivity compared to 'O/cm, and how high this thermal conductivity is to be determined is determined by considering the temperature rise characteristics of the engine and the environmental temperature in which it will be used. In order to increase the thermal conductivity, it is sufficient to appropriately set the type or mixing ratio of the selected high thermal conductivity material to obtain the optimum thermal conductivity.

According to the above, when the temperature of the engine 1 increases, the temperature of the engine 1 is transmitted to the intake pipe 8 in a short time and the temperature of the intake pipe 8 can be increased, so that the fuel flowing inside the intake pipe 8 is heated. The fuel is efficiently atomized on the inner wall of the intake pipe 8, which improves the mixing of air and fuel, improving the combustibility of the engine and improving performance.

On the other hand, as mentioned above, the temperature of the intake pipe 8 increases as the temperature of the engine 1 increases, but since the thermal conductivity has increased, the heat dissipation from the intake pipe 8 to the surroundings also increases. ,
A large increase in the temperature of the intake pipe 8 is suppressed.

Therefore, the temperature of the fuel supply device 2 connected to the intake pipe 8 can be kept within a constant temperature range, so that fuel paper is less likely to form in small diameter passages, such as the fuel passage of a carburetor. This made it possible to completely prevent the fuel paper lock phenomenon.

In this embodiment, the synthetic resin material used as the base material of the intake pipe 8 may be either thermoplastic or thermosetting, and may be selected from polyacetal, polyolefin, polystyrene, polycarbonate, polyamide, etc. depending on the purpose. Additive materials that are of good quality and have higher thermal conductivity than the base material include iron, copper, chromium, carbon, tungsten, and the like.

〔Effect of the invention〕

As described above, the intake pipe for an internal combustion engine according to the present invention provides the following effects.

■While it has the advantages of intake pipes made of synthetic resin materials, such as light weight, good corrosion resistance, and good inner surface roughness, the temperature rises quickly when it receives heat from the outside.
- Since we were able to provide an intake pipe with excellent lift characteristics, we were able to improve the atomization performance of the fuel within the intake pipe, making it possible to further improve the operability of the engine. In particular, we were able to see a significant improvement in drivability from starting when the engine ambient temperature was low to completing warm-up.

■While the engine is running, the heat received by the intake pipe from the engine is absorbed by the intake pipe itself's self-heat dissipation effect (due to its high thermal conductivity), which enables sufficient heat dissipation, and the temperature of the intake pipe increases. Since the temperature rise could be suppressed to, for example, around 60°C, the paper lock phenomenon in the fuel supply system, especially in the fuel passage, could be completely suppressed, and the performance could be further stabilized.

[Brief explanation of the drawing]

FIG. 11 is a system diagram of the entire engine showing one embodiment of the intake pipe in the internal combustion engine according to the present invention. i, Internal combustion engine 2, Fuel supply device 8, Intake pipe

Claims (2)

[Claims] (1) In an intake pipe of an internal combustion engine that supplies fuel supplied from a fuel supply device to the internal combustion engine via the intake pipe; An intake pipe for an internal combustion engine, which contains an additive material having a thermal conductivity higher than that of the synthetic resin material. (2) The intake pipe for an internal combustion engine according to claim 1, wherein the additive material is a metal material.