KR0169897B1 - Fuel evaporate gas control system of an automobile - Google Patents

Abstract

The present invention relates to an evaporation gas control system having a liquid fuel return structure, in particular, when the conduit between the canister and the engine is long, condensed fuel of the evaporation gas on the conduit increases the ventilation resistance and prevents the purge efficiency from dropping. The present invention relates to a boil-off gas control system having a return structure of condensed liquid fuel which can be easily enlarged in size and can easily cope with boil-off gas regulation.

The system of the present invention is an evaporation gas control system for supplying evaporated gas collected from a canister to an engine by evaporating from a fuel tank according to an opening of a purge control valve, wherein the liquid fuel is installed between the canister and the purge control valve and liquefied in a pipeline And a one-way check valve disposed on a conduit between the liquid fuel collecting means and the fuel tank to stop the flow in the reverse direction.

Description

Evaporative Gas Control System with Liquid Fuel Return Structure

The present invention relates to an evaporation gas control system having a liquid fuel return structure, in particular, when the conduit between the canister and the engine is long, condensed fuel of the evaporation gas on the conduit increases the ventilation resistance and prevents the purge efficiency from dropping. A boil-off gas control system having a return structure of a liquid fuel condensed to make it possible.

Liquid fuel used as a vehicle fuel is supplied to the engine by a fuel pump while stored in a fuel tank. In this case, the fuel tank is filled with liquid fuel, that is, HC gas evaporated from gasoline or diesel.

The boil-off gas is emitted from the fuel tank to the atmosphere when the lid is opened when refueling or when the vehicle is driven or stopped due to incomplete sealing of the fuel inlet, causing optical smog and respiratory failure of the human body. It is a factor.

Accordingly, each country regulates the amount of pollutants in the combustion exhaust gas and at the same time regulates the emission of the boil-off gas to below a certain level.

A conventional boil-off gas control system for reducing the air emissions of boil-off gas and saving fuel is shown in FIG.

The boil-off gas control system shown in FIG. 1 is installed in the fuel tank 1 to prevent the fuel from entering the charcoal canister, and to store the boil-off gas in the fuel tank 1 when the engine is stopped. A purge control solenoid valve 9 for adjusting the amount of evaporated gas supplied from the canister 5 to the intake manifold 7 according to the control of the charcoal canister 5 and the engine control unit ECU, and the ECU for system control. It consists of (11). Reference numeral 13 is a check valve for adjusting the pressure of the fuel tank (1).

The evaporation gas control system collects the HC gas evaporated from the fuel tank 1 into the canister 5 and purge control solenoid valve 9 so that the ECU 11 can maintain the best engine operating state according to the engine operating state. By controlling the control amount of the boil-off gas supplied to the intake manifold (7).

However, in the system, since the pipeline between the canister and the engine is composed of a hose / pipe / tube, etc., when the ambient temperature falls on the pipeline, the evaporated gas may be condensed into a liquid. In this case, the condensed liquid fuel has a problem in that the purge efficiency is reduced because it reduces the cross-sectional area of the pipe to increase the ventilation resistance.

Moreover, in order to cope with the new evaporation gas and ORVR (On Board Refueling Vapor Recovery) regulations in Bumi area, the canister is enlarged and installed at the rear of the vehicle (around the fuel tank) for ease of installation. In this case, however, the pipeline between the canister and the engine is lengthened, which adds to the seriousness. In addition, as the canister becomes larger, the supply amount of the boil-off gas flowing into the engine also increases, which makes it difficult to control the air-fuel ratio (A / F).

The present invention has been made in view of the above-described problems of the prior art, the object of which is to prevent the condensed fuel of the boil-off gas on the conduit increases the ventilation resistance when the conduit between the canister and the engine is long to prevent the purge efficiency is lowered Accordingly, the canister can be easily enlarged to facilitate the regulation of new evaporation gas, and the control of the air-fuel ratio can be easily controlled by reducing the evaporation gas flowing into the engine, and condensation can be saved by returning the condensed fuel. To provide a boil-off gas control system having a return structure of liquid fuel.

1 is a control system diagram of a conventional boil-off gas control system.

2 is a control system diagram of an evaporative gas control system having a liquid fuel return structure according to the present invention.

* Explanation of symbols for main parts of the drawings

1: fuel tank 3: separator

5: canister 7: intake manifold

9: Purge Control Valve 11: ECU

13: check valve 21: vapor chamber

23: 1 way check valve 25: 4th pipe

27: first duct 29: second duct

31: Third Route

In order to achieve the above object, the present invention is provided between the canister and the purge control valve in the evaporation gas control system for supplying evaporated gas collected from the fuel tank to the engine according to the opening of the purge control valve. Liquid collecting means for collecting the liquid fuel liquefied in the pipeline and returning it to the fuel tank, and a one-way check valve disposed on the conduit between the liquid fuel collecting means and the fuel tank to block the reverse flow. It provides a boil-off gas control system having a liquid fuel return structure, characterized in that configured.

As described above, the present invention collects the condensed liquid fuel generated on the boil-off gas line by the vapor chamber installed on the conduit between the canister and the purge control valve and returns the collected liquid fuel to the fuel tank through the feedback line.

Therefore, when the canister is installed near the fuel tank and the pipeline between the canister and the engine is long, condensed fuel of the boil-off gas increases the aeration resistance and prevents the purge efficiency from dropping. Therefore, the canister can be easily enlarged. Responding to the regulation of new evaporation gas can be facilitated, control of the air-fuel ratio is facilitated by the reduction of the boil-off gas flowing into the engine, and the fuel can be reduced according to the return of the condensed fuel.

EXAMPLE

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

2 is a control system diagram of a boil-off gas control system having a liquid fuel return structure according to the present invention. As shown in the present invention, in the present invention system, the tank pressure on the first conduit 27 from the fuel tank 1 is used. The canister 5 through which the evaporation gas is collected is connected through the 2-way check valve 13, and the outlet of the canister 5 is connected to the inlet of the vapor chamber 21 through the second pipe 29. The upper outlet of the chamber 21 is connected to the purge control valve 9 through a third conduit 31, and the lower outlet of the vapor chamber is a one-way check valve 23 and a fourth conduit for preventing reverse flow. It is connected back to the fuel tank 1 via 25. In addition, the outlet of the purge control valve 9 is connected to the engine or surge tank, it is opened and closed under the control of the ECU.

It will be described in detail the operation of the boil-off gas control system of the present invention configured as described above.

In the system of the present invention, when the evaporated gas evaporated from the fuel tank 1 becomes higher than a predetermined pressure, it is collected in the canister 5 through the two-way valve 13 on the first conduit 27. In this case, the canister can be installed around the fuel tank 1 by greatly increasing the capture capacity of the boil-off gas.

The vaporized gas collected in the canister 5 is then vaporized under the control of the ECU. The purge control valve 9 opens and is supplied to the intake manifold of the engine via the second long passage 29 to the vapor chamber 21. Will go through.

At this time, the liquid fuel condensed in the vapor chamber 21 and the liquid fuel condensed on the second conduit 29 flow from the lower outlet through the one-way check valve 23 on the fourth conduit 25 through the fuel tank 1. Is returned to the chamber, and the boil-off gas collected in the chamber is absorbed into the intake manifold on the engine side through the purge control valve 9 on the third conduit 31.

This structure feeds the liquefied liquid fuel back to the fuel tank without a separate control device except the vapor chamber.

As described above, the present invention collects the condensed liquid fuel generated on the boil-off gas line by the vapor chamber installed on the conduit between the canister and the purge control valve and returns the collected liquid fuel to the fuel tank through the feedback line.

Therefore, it is possible to increase the purge efficiency by reducing the aeration resistance caused by condensed fuel on the pipeline between the canister and the engine. Accordingly, the canister can be easily enlarged to cope with the regulation of new evaporation gas. The reduction makes it easier to control the air-fuel ratio, and the fuel can be reduced according to the return of the condensed fuel.

In the above, the present invention has been illustrated and described with reference to specific preferred embodiments, but the present invention is not limited to the above-described embodiments, and the present invention is not limited to the spirit of the present invention. Various changes and modifications can be made by those who have

Claims (2)

An evaporative gas control system for evaporating gas evaporated from a fuel tank and collected in a canister to an engine according to an opening of a purge control valve, wherein the liquid fuel disposed between the canister and the purge control valve is collected to collect the liquid fuel in a pipeline. A liquid fuel return structure comprising a liquid fuel collecting means for returning to a fuel tank, and a one-way check valve disposed on a conduit between the liquid fuel collecting means and the fuel tank to prevent a reverse flow. Having an evaporative gas control system. The liquid fuel collecting means of claim 1, wherein an inlet is connected to the canister through a first conduit, a first outlet for boil-off gas is connected to the purge control valve, and a second outlet for liquid fuel is the one-way. Evaporation gas control system having a liquid fuel return structure, characterized in that the vapor chamber is connected to the check valve.