JPS5941650A - Preventive device against fuel evaporative loss of internal-combustion engine - Google Patents

Abstract

PURPOSE:To make the purge flow of each adsorptive canister securable sufficiently, by letting a device perform each exhaust of fuel vapor out of respective absorptive canisters separately. CONSTITUTION:A first canister 2 opening an atmospheric open port 10 at its lower part is connected to a fuel tank 1 through a fuel vapor leading-in pipe 6 and simultaneously connected to a discharge port 10-a opened just above a throttle valve 9 existing in an idle position through a fuel vapor discharge pipe 12. In addition, a second canister 4 opening an atmospheric open port 11 at its lower part likewise is connected to an outer bent 20 of a float chamber 3 by means of fuel vapor leading-in pipes 8 interposing a soelnoid valve 7 in between the also connected to a discharge port 19-b through a fuel vapor leading-in pipe 13. Then, the solenoid valve 7 is opened in time of an ignition switch 22 being open, and in time of engine stoppage, the fuel vapor produced out of the float chamber 3 is made so as to cause it to be adsorbed in the second canister 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel evaporation loss prevention device for an internal combustion engine, and in particular, an adsorption vessel for temporarily adsorbing and storing fuel vapor from two fuel reservoirs is provided in correspondence with each fuel reservoir. The present invention relates to a fuel evaporation loss prevention device having two devices in total, one for each device.

Conventionally, in a fuel evaporation loss prevention device for an internal combustion engine, as shown in FIG. Some are equipped with a second charcoal canister 4 for temporarily adsorbing and storing fuel vapor from the fuel tank. The fuel vapor generated in the fuel tank 1 passes through the first fuel vapor introducing vibro and is adsorbed and contained in the first charcoal canister 2, and the fuel vapor generated in the float chamber 3 of the vaporizer 5 is passed through the electromagnetic valve 7. The fuel vapor passes through the second fuel vapor introduction pipe 8 and is adsorbed and accommodated in the second charcoal canister 4 . When the engine is operated and the throttle valve 9 is opened beyond the idle opening, the fuel vapor adsorbed and contained in the first and second charcoal canisters 2.4 is released into the first and second atmosphere openings. 10. The activated carbon is purged by the air drawn in from 11 to the first fuel vapor exhaust pipe 12 and the second fuel vapor exhaust pipe 1.
3 and is sucked into the fuel vapor outlet 16 of the vaporizer 5.

In this case, the first fuel vapor exhaust pipe 12 and the second fuel vapor exhaust pipe 13 are joined by a three-way collection path 14 midway to form a fuel-1 steam exhaust collection pipe 15. . Therefore, if there is a difference in the adsorption amount of fuel vapor between the first charcoal canister 2 and the second charcoal canister 4, that is, if there is a difference in ventilation resistance between the two charcoal canisters 2.4, the fuel vapor adsorption A charcoal canister with a small amount of fuel vapor and low ventilation resistance has a high purge flow rate, while a charcoal canister with a large amount of fuel vapor adsorption and high ventilation resistance has a low purge flow rate. This difference in purge flow rate tends to increase over time, and eventually becomes extreme, leading to the direction that should be expected from a technical standpoint. There was a problem in that the purge flow rate of the canister was completely contradictory to the direction of reducing the purge flow rate of the charcoal canister, which has a small amount of fuel vapor adsorption and low ventilation resistance.

An object of the present invention is to provide a fuel evaporation loss prevention device for an internal combustion engine equipped with two fuel vapor adsorption vessels, in which a difference occurs in the amount of fuel vapor adsorption between the two fuel vapor adsorption vessels, resulting in unbalanced ventilation resistance. The objective is to ensure the purge flow rate of each fuel vapor adsorption container by preventing the purge flow rates of each fuel vapor adsorption container from influencing each other even if the purge flow rate of each fuel vapor adsorption container occurs.

According to the present invention, two fuel vapor discharge ports for discharging fuel vapor are provided in the engine intake system, and a fuel discharge pipe for discharging the adsorbed fuel is connected to each of the two fuel vapor adsorption vessels. This is achieved by a fuel evaporation loss prevention device for an internal combustion engine, which is characterized by independently piping the vapor adsorption vessels.

Next, embodiments of the present invention will be described in detail based on the drawings. 2 and 3 show a first embodiment of the present invention, FIG. 2 is an overall system diagram of a fuel evaporation loss prevention device for an internal combustion engine, and FIG. 3 is a diagram of the fuel vapor loss prevention device shown in FIG. FIG. 3 is an enlarged cross-sectional view of a discharge port portion. In FIG. 2 and FIG. 3, the same parts as in FIG. 1 will be explained using the same numbers. The first charcoal canister 2 is connected to the fuel tank 1 by a first fuel vapor introducing vibro, and temporarily adsorbs and accommodates the fuel vapor generated in the fuel tank 1 using activated carbon 17 . At the bottom of the first charcoal canister 2, an air opening 10 is opened to introduce air for purging the fuel vapor adsorbed on the activated carbon 17. The throttle bore 18 of the carburetor 5 has two holes for discharging fuel vapor.
The fuel vapor exhaust ports 19-a and 19-b are located directly above the throttle valve 9 when the throttle valve 9 is in the idle position, and are located downstream of the throttle valve 9 when the throttle valve 9 is in the other opening position. They are arranged in parallel at different positions. FIG. 3 shows an enlarged cross-sectional view of the fuel vapor exhaust ports 19-a and 19-b. In FIG. 3, the throttle valve 9 is opened more than the idle opening. The first fuel vapor outlet 19-a and the first charcoal canister 2
and is connected by a first fuel vapor exhaust pipe]2. The second charcoal canister 4 is located in the float chamber 3c of the vaporizer 5.

It is connected to the outer vent 20 by a second fuel vapor introduction pipe 8, and the fuel vapor generated in the float chamber 3 is temporarily adsorbed and contained by the activated carbon 21. A solenoid valve 7 is interposed in the middle of the second fuel vapor introduction pipe 8, and the solenoid valve 7 is electrically connected to a battery 23 via an ignition switch 22. When the ignition switch 22 is closed, the solenoid valve 7 closes the second fuel vapor introduction pipe 8, and only when the ignition switch 22 is opened and the engine is stopped, the solenoid valve 7 closes the second fuel vapor introduction pipe 8. Open the second fuel vapor introduction pipe 8. At the bottom of the second charcoal canister 4, an air opening 11 is opened to introduce air for purging the fuel vapor adsorbed on the activated carbon 21. The second charcoal canister 4 and the second fuel vapor exhaust port 19 - b of the carburetor 5 are connected by a second fuel vapor exhaust pipe 13 .

Next, the operation of the above first embodiment will be explained below.

In FIG. 2, fuel vapor generated in the fuel tank 1 passes through a first fuel vapor introducing vibro and is adsorbed onto the activated carbon 17 of the first charcoal canister 2. On the other hand, when the ignition switch 22 is opened, the solenoid valve 7 is opened, and the fuel vapor generated in the float chamber 3 passes through the second fuel vapor introduction pipe 8 to the activated carbon 21 of the second charcoal canister 4. It is adsorbed. When the ignition switch 22 is closed to operate the engine and the throttle valve 9 is opened beyond the idle opening, negative pressure acts on the first and second fuel vapor exhaust ports 11 a and 19 - b. The negative pressure is transmitted to the first charcoal canister 2 and the second charcoal canister 4 through the first fuel vapor exhaust pipe 12 and the second fuel vapor exhaust pipe 13, respectively. Therefore, air is sucked in from the atmosphere opening 10 of the first charcoal canister 2, and the fuel vapor adsorbed on the activated carbon 17 is purged by the air, and the fuel vapor is purged through the first fuel vapor exhaust pipe 12. The fuel vapor is discharged into the vaporizer 5 from the fuel vapor outlet 19-a. Similarly, air is sucked in from the atmosphere opening 11 of the second charcoal canister 4, and the fuel vapor adsorbed on the activated carbon 21 is purged by the air and passes through the second fuel vapor exhaust pipe 13. Second fuel vapor outlet 19-
b is discharged into the vaporizer 5.

As mentioned above, the first charcoal canister 2 and the second
The fuel vapor is discharged from and to the charcoal canister 4 independently.

Next, a second embodiment of the present invention will be described based on FIG. 4. Note that the same parts as in FIG. 3 will be described with the same numbers. In FIG. 4, the first and second
The fuel vapor exhaust ports 19-a and 19-b are provided in the gathering portion 25 of the intake manifold 24. A first electromagnetic valve 26 is interposed in the middle of the first fuel vapor exhaust pipe 12 that connects the first fuel vapor outlet 19-a and the first charcoal canister 2. A second electromagnetic valve 27 is interposed in the middle of the second fuel vapor exhaust pipe 13 that connects the second fuel vapor outlet 19 - b and the second charcoal canister 4 .

The first and second solenoid valves 26 and 27 are connected to the computer 28.
controlled by Various control variables representing the operating conditions of the engine and vehicle are entered manually into the computer 28. The rest of the configuration is exactly the same as the case of FIG. 3, so the explanation thereof will be omitted, and the operation of the second embodiment will be explained. In FIG. 4, when the engine is idling or when the engine is operating other than during deceleration, the first and second solenoid valves 26.27 are connected to the first and second fuel vapor discharge pipes 12.13 according to instructions from the computer 28. is open. Therefore, the fuel vapor adsorbed and accommodated in the first charcoal canister 2, the second charcoal canister 4, and the first charcoal canister 4 are independently transferred to the first fuel vapor exhaust pipe 12 and the second fuel vapor exhaust pipe 13. through the first and second fuel vapors J
Intake manifold 24 from Ji outlet +9-a, 19-b
It is discharged to a collecting section 25. Other effects include the first
Since this is exactly the same as in the embodiment, the explanation thereof will be omitted.

As described above, according to the fuel evaporation loss prevention device for an internal combustion engine according to the present invention, the fuel vapor is discharged from the two fuel vapor adsorption vessels independently, so that Even if there is a difference in ventilation resistance, each purge flow rate does not affect each other, and the effect is that the purge flow rate of each fuel vapor adsorption container is ensured.

[Brief explanation of the drawing]

FIG. 1 is an overall view of a conventional fuel evaporation loss prevention device for an internal combustion engine, and FIG. 2 is an overall view (11) of a fuel evaporation loss prevention device for an internal combustion engine showing a first embodiment of the present invention. Fig. 3 is an enlarged cross-sectional view of the steam exhaust port in Fig. 2, and Fig. 4 is an overall view of the fuel evaporation loss prevention device for an internal combustion engine showing the second embodiment of the present invention. It is a diagram. 1゜-----Fuel tank 2----- First charcoal canister 3----
-Flow I/chamber 4---charcoal canister 6 of ffi 2---
---First fuel vapor introduction pipe 8--Second fuel vapor introduction pipe 12--First fuel vapor exhaust pipe 13--Second fuel vapor exhaust pipe 19-a-- ---First fuel vapor exhaust "11"-b--Second fuel vapor exhaust port 26--First solenoid valve 27--Second solenoid valve (12)

Claims (2)

[Claims] (1) A fuel evaporation loss prevention device for an internal combustion engine, characterized by comprising the following constituent elements. 7 (a) A first fuel vapor adsorption container for temporarily adsorbing and storing fuel vapor generated from the first fuel reservoir (b) Temporarily adsorbing and storing fuel vapor generated from the second fuel reservoir A second fuel vapor adsorption container (c)%(f) is located directly in front of the throttle valve when the throttle valve is at the idle opening position, and when the throttle valve is at the idle opening position, (d) a first fuel vapor outlet and a second fuel vapor outlet opened in parallel at a position downstream of the throttle valve when the opening is other than that of the throttle valve; (e) a first fuel vapor exhaust pipe that communicates between the adsorption container and the first fuel vapor exhaust port; (e) a second fuel vapor exhaust pipe that connects the second fuel vapor adsorption container and the second fuel vapor exhaust port; steam exhaust pipe (2) A fuel evaporation loss prevention device for an internal combustion engine, characterized by comprising the following constituent elements. (B) A first fuel vapor adsorption container for temporarily absorbing and storing fuel vapor generated from the first fuel reservoir (B) For temporarily adsorbing and housing fuel vapor generated from the second fuel reservoir a second fuel vapor adsorption container (c) a first fuel vapor exhaust port and a second fuel vapor exhaust port opened to the intake manifold of the engine or the intake passage of its gathering part; (d) the first fuel vapor exhaust port; a first fuel vapor exhaust pipe connecting the fuel vapor adsorption container and the first fuel vapor outlet;
a first electromagnetic valve that opens only at a predetermined time during engine operation; and a second fuel vapor exhaust pipe that connects the second fuel vapor adsorption container and the second fuel vapor outlet. interposed in the middle of the second fuel vapor exhaust pipe,
A second solenoid valve that opens only at specified times during engine operation.