JPS6323379B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a device for reducing the loss of gasoline, etc. that evaporates from a gasoline tank or engine carburetor system.

<Prior Art> In the automobile industry, air pollution has been a problem due to automobile exhaust gas, but in addition to this, vapors from gasoline tanks and carburetors are also a cause of pollution.

Approximately 60% of the hydrocarbons (gasoline vapor, etc.) emitted from all automobiles are exhaust gas, and about 20% of the other
% is blow-by gas, and the remaining 20% is evaporation from the fuel system.Regarding the regulation of vaporized components of hydrocarbons, it is necessary to install blow-by gas emission prevention devices and regulate the amount of hydrocarbon emissions in exhaust gas. Following this, from 1972 it became mandatory to install gasoline evaporation suppression devices.

A conventional evaporative fuel suppression device (hereinafter referred to as canister) will be explained with reference to Figs. 1 and 2. When gasoline in a gasoline tank 1 starts to evaporate due to pressurization, temperature rise, etc., the pressure inside the tank increases. The fuel then passes through the vaporization separator 2, passes through the vaporized fuel control device 5, pushes open the check valve in the canister 3, and flows into the activated carbon layer 11. At this point, when the engine is stopped, no negative pressure is applied to the carburetor, and the gasoline vapor that has entered the
Only the air adsorbed by the activated carbon and remaining is discharged to the outside air through the purge tube 8.

On the other hand, when the engine is running, the control valve of the canister acts with negative pressure, opens a passage to the carburetor 4, and the gasoline vapor component adsorbed on the activated carbon is desorbed by the outside air sucked in from the purge tube 8, and is removed from the carburetor. 4 and will be combusted. These technologies are USP No.
No. 3683597, Special Publication No. 143912, Publication No. 143912, Actual Publication No. 143912
- Disclosed in Publication No. 22885 and Japanese Patent Application Laid-Open No. 1983-59215.

<Problems to be Solved by the Invention> The above-described conventional canister has a problem in that the activated carbon of the evaporated fuel lacks dispersibility. Another problem is that with respect to the function of controlling the air-fuel ratio, there are various methods, such as a fixed ball spring type and a diaphragm valve seat, but the mechanism is complicated and uneconomical. In addition, common to all types, there is a risk of short-path of evaporated gas due to the criticality between the main body housing and the activated carbon.

<Means for Solving the Problems> The present inventors have completed the present invention with the aim of solving the above-mentioned problems and providing a canister that is excellent in suppressing evaporated fuel. That is, the present invention includes a main body housing having an inlet connected to a gasoline tank on the upper wall and a large number of air holes on the bottom wall, and a main body housing provided vertically on the bottom wall of the main body housing. This is an evaporative fuel suppression device for an automobile, comprising a check valve element whose upper part is fitted into the hollow part of the hollow filter member and whose lower end is formed with an outlet that contacts a carburetor.

The material of the hollow filtration member used in the present invention is preferably nylon or nylon+urethane in terms of gasoline resistance, gasoline permeability, and heat resistance. However, other resin members can also be used.

<Function> In the canister of the present invention, a hollow filtration member is provided in the center of the main body housing, and activated carbon is filled around the hollow filtration member, so that the evaporated fuel that has flowed into the hollow filtration member can interact with the inside of the activated carbon region. Since the adsorbent absorbs and desorbs to the lower layer of the activated carbon, the efficiency of the adsorbent can be increased, and therefore the amount of activated carbon can be smaller than before, and the canister can be made smaller.

<Embodiment> Hereinafter, a preferred embodiment of the present invention will be described based on the drawings.

FIG. 3 is a sectional view of the canister of the present invention. In the embodiment shown in the third figure, an outflow port 32 provided on the bottom wall of the main housing 31 communicates with the engine carburetor, and an inflow port 33 provided on the top wall communicates with the gasoline tank. The system has a hollow filter member 34 molded from nylon resin + urethane resin in the center and a check valve valve body 35 inside this filter member, and when the engine is stopped, that is, the pressure on the outlet port 32 side is not negative than atmospheric pressure. At this time, the valve of the check valve body 35 is not opened, and the gasoline vapor flowing in from the inlet 33 communicating with the gasoline tank is filtered through the hollow filter member 34 provided in the main body housing 31.
The activated carbon 36 surrounding the activated carbon 36, the upper and lower filters 37 holding the activated carbon 36, and the upper part of the lattice-like annular grit 38 flow into an adsorption mechanism that is tightly supported via a coil spring 39, and the gasoline vapor flows into the activated carbon 36. The residual fresh air is discharged to the atmosphere through the lower filter 37 and the pores 40 of the checkered annular grid 38.

Next time the engine is started, the pressure on the carburetor side [outlet 32 side] becomes more negative than the atmospheric pressure, so the check valve body 35 closes and fresh air flows into the porous part 40 and the lower part. It passes through the lattice-like annular grid 38 and the filter 37, and desorbs the vaporized gasoline adsorbed on the activated carbon 36 to form a gasoline mixture, which is sucked into the carburetor and combusted.

<Effects of the Invention> By providing a hollow filtration member between an inlet and two openings functioning as an inlet, the activated carbon layer can be used widely, especially to the lower part, and the activated carbon can be adsorbed. By increasing efficiency, the adsorption effect is naturally greater even with a smaller amount of activated carbon than in the past, and the canister can be made smaller accordingly. Moreover, according to this shape and structure, the canister can be used even when lying on its side, the main body housing base material is also made of resin, it is inexpensive, and there is little air pollution caused by gasoline vapor.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional system diagram of the general mechanism of a conventional fuel vapor suppression device. FIG. 2 is a cross section of the evaporative fuel suppression device (canister) shown in FIG. 1, which is a conventional embodiment. FIG. 3 is a sectional view of the evaporative fuel suppression device (canister) of the present invention. 1: Gasoline tank, 2: Gas-liquid separator, 3: Fuel vapor suppression device, 4: Carburetor, 5: Fuel vapor control device, 31: Main body housing, 32: Outlet, 33: Inlet, 34: Hollow filter member , 35:
Check valve body, 36: activated carbon, 37: filter, 38: lattice-like annular grit, 39: coil spring, 40: porous portion.

Claims (1)

[Claims] 1. A main body housing having an inlet connected to a gasoline tank on the upper wall and a large number of air holes on the bottom wall, a hollow filtration member inside the main body housing, and a hollow filtration member surrounding the hollow filtration member. filled with activated carbon, and a check valve element that is erected on the bottom wall of the main body housing, whose upper part is fitted into the hollow part of the hollow filter member, and whose lower end has an outlet connected to the carburetor. An evaporative fuel suppression device for an automobile, comprising: