KR20010002286U - Residual Gas Removal Device for Elpji Vehicles - Google Patents

Abstract

The present invention relates to a device for removing residual gas of an LPG vehicle, comprising: an evaporator for depressurizing and vaporizing a liquid fuel gas (LPG) in a liquid state, and a mixer for mixing vaporized gas with external air introduced through an air cleaner. And a solenoid valve installed to open and close a flow path according to a drive signal of an electronic control unit (ECU) on a gas connection pipe installed between the mixer and the evaporator, wherein the starting is stopped between the mixer and the surge tank. It is characterized in that it further comprises a residual gas removing means for forming a separate negative pressure for a predetermined time from the moment to prevent the gas remaining in the gas connection pipe between the evaporator and the mixer is introduced into the surge tank and not remain.

Therefore, according to the present invention, even if the engine is stopped, the residual gas introduced into the surge tank is quickly discharged using a separate negative pressure forming means, thereby maximizing the discomfort felt by the driver or the passenger due to the residual gas.

Description

Residual Gas Removal Device for Elpji Vehicles

The present invention relates to an apparatus for removing residual gas of an LPG vehicle, and more particularly, to an apparatus for removing residual gas of an LPG vehicle that can remove fuel gas (LPG) remaining in a surge tank when an engine is stopped. It is about.

In general, liquefied petroleum gas (Liquefied Petroleum Gas; LPG) is a mixture of propane and butane. This fuel gas is liquid only at pressures much higher than atmospheric, so it vaporizes as the pressure decreases. Therefore, the fuel supply system for storing LPG gas under high pressure should be kept completely airtight.

FIG. 1 schematically illustrates a fuel gas supply apparatus of a conventional LPG vehicle, and includes an evaporator for depressurizing and vaporizing a liquid fuel gas LPG through a filter and a high pressure regulator (not shown) in a fuel tank (not shown). 1) is connected to the pipe, the evaporator (1) is connected by a mixer (2) and a gas connection pipe (8) for mixing the vaporized gas and the outside air introduced through the air cleaner (3). The mixer 2 is configured to supply a gas mixed with air to the intake manifold 5 via a surge tank 4 storing negative pressure. On the gas connection pipe 8 between the evaporator 1 and the mixer 2, a solenoid valve 6 which is opened and closed by a drive signal of an electronic control unit (ECU) 7 is coupled to control the inflow and outflow of fuel gas. have.

In the fuel gas supply apparatus of the conventional LPG vehicle provided as described above, when the solenoid valve 6 is opened in response to the driving signal of the electronic control unit 7, the LPG gas in the liquid state that is pumped by the vapor pressure of the fuel tank (not shown) is evaporated. After depressurizing in (1), it is vaporized and flows into the mixer (2). At this time, the engine is started by mixing the vaporized gas with the outside air introduced through the air purifier 3 and entering the cylinder (not shown) by the negative pressure of the surge tank 4 and the intake manifold 5. On the other hand, when the engine is stopped, the solenoid valve 6 is closed to block the inflow of fuel gas.

Thus, the conventional LPG vehicle engine is a carburetor type mainstream, which is a method of controlling the amount of fuel gas introduced by the negative pressure formed in the surge tank 4, and by using a small amount of fuel gas for safety at idle Although controlled by the pass, most of them are supplied in the same manner as described above.

In this way, the amount of gas remaining between the gas connecting pipe 8 between the mixer 2 and the evaporator 1 is forced to leak into the surge tank 4 immediately after the start-up, and is specifically treated. There is no device to do that. Therefore, when driving an LPG vehicle, such as a taxi, there is a problem that drivers or passengers feel more dizziness or other discomfort due to the smell of LPG gas leaking out.

Therefore, the present invention was devised to solve the above-described problems, and an object of the present invention is to prevent fuel gas (LPG) from flowing into the surge tank even when the engine is stopped, thereby reducing the discomfort of the driver or passenger. A residual gas removal apparatus of a vehicle is provided.

In order to achieve the above object, a residual gas removal apparatus of an LLP vehicle according to the present invention includes an evaporator configured to depressurize and vaporize a liquid fuel gas (LPG) in a liquid state, and external air and vaporized gas introduced through an air cleaner. An LPI vehicle comprising a mixer to mix and a solenoid valve installed to open and close a flow path in response to a drive signal of an electronic control unit (ECU) on a gas connection pipe provided between the mixer and the evaporator. It characterized in that it further comprises a residual gas removal means for forming a separate negative pressure for a predetermined time from the moment the start is stopped so that the gas remaining in the gas connection pipe between the evaporator and the mixer does not flow into the surge tank to remain therein. .

1 is a view schematically showing a fuel gas supply apparatus of a conventional LLP vehicle.

2 is a view schematically showing an apparatus for removing residual gas of an LLP vehicle according to the present invention;

Explanation of symbols on the main parts of the drawings

21: evaporator, 22: mixer,

23: air purifier, 24: surge tank,

26, 46: solenoid valve, 27: electronic control unit (ECU),

28: gas connection pipe, 40: residual gas removal means,

42: residual gas flow tube, 44: vacuum canister.

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

2 is a view schematically showing an apparatus for removing residual gas of an LPI vehicle according to the present invention.

In the drawing, a gas connection tube (e.g., a mixer 22) for mixing the vaporized gas and the external air introduced through the evaporator 21 and the air cleaner 23 to reduce the pressure of the liquid gas LPG in the liquid state to vaporize. 28) are interconnected.

In addition, a surge tank 24 storing negative pressure at an outlet side of the mixer 22 is connected to supply a gas mixed with air into the cylinder (not shown) through the intake manifold 25.

On the gas connection pipe 28 between the evaporator 21 and the mixer 22, a solenoid valve 26, which is opened and closed by a drive signal of an electronic control unit (ECU) 27, is coupled to control the inflow and outflow of fuel gas. .

Particularly, reference numeral 40 denotes a residual gas removing means, in which a fuel gas remaining in the gas connecting pipe 28 between the evaporator 21 and the mixer 22 is formed by forming a separate negative pressure for a predetermined time from the moment when the start is turned off. (24) It does not flow in and remain inside.

That is, the residual gas removing means 40 serves as a vacuum storage tank at the end of the residual gas flow tube 42 and the residual gas flow tube 42 further installed between the mixer 22 and the surge tank 24. And a solenoid valve 46 which opens and closes a flow path in response to a drive signal of an electronic control unit (ECU) 27 on the gas flow pipe 42. .

Here, the vacuum canister 44 is a built-in activated carbon that can absorb the residual LPG gas, the conventional canister has a connector from the fuel tank, an atmospheric pressure opening connector, a connector to the purge control valve, The canister of this embodiment is a form in which only the purge side is left.

The residual gas removal apparatus of the LPG vehicle according to the present invention provided as described above stores the negative pressure of the surge tank 24 in the vacuum canister 44 which simultaneously serves as the canister and the vacuum storage tank of the gasoline engine vehicle while driving. The solenoid valve 46 is driven for a predetermined time from the moment when the start is turned off after the end of the driving, and the LPG fuel gas remaining by the negative pressure formed by the vacuum canister 44 is sucked into the activated carbon.

Subsequently, upon restarting, LPG gas stored in the vacuum canister 44 is introduced into the surge tank 24 again within a range that has a minimum effect on the air-fuel ratio in accordance with a normal purge control logic to enable combustion. do.

In this embodiment, the electronic control unit (ECU) 27 drives the solenoid valve 46 as shown in the table below, where t1 to t4 are measured by a pressure sensor or the like when the engine is opened and mapped in advance to the ROM. It is a value.

t1: Mapping time until engine ignition is completed and negative pressure of surge tank 24 changes to atmospheric pressure.

t2-t1: Mapping by measuring the time when the flow rate characteristics of the solenoid valve 46 and the pressure of the surge tank 24-the vacuum canister 44 are balanced in a very short time.

t3 to t4: Use the fuzzy control logic used in a normal gasoline engine. However, since the mixer 22 cannot precisely control the amount of LPG gas structurally, the amount of the mixer 22 should be less than that of a gasoline vehicle so as not to cause an unbalance of air-fuel ratio or vibration generated during idle.

Ignition switch Just before OFF OFF + t1 OFF + t2 After OFF + t2 Solenoid valve OFF ON OFF OFF Residual gas flow pipe Closure Opening Closure Closure Pressure state of surge tank Negative pressure Atmospheric pressure Atmospheric pressure Atmospheric pressure Pressure state of vacuum canister Medium pressure Negative pressure Negative pressure Negative pressure action LPG is flowing inside the surge tank. Residual gas enters the vacuum canister. Solenoid valve closes when pressure is balanced. No LPG movement after solenoid valve is closed.

Ignition switch Immediately after ON + t3 ON + t4 After ON + t4 Solenoid valve OFF ON OFF OFF Residual gas flow pipe Closure Opening Closure Closure Pressure state of surge tank Medium pressure Negative pressure Negative pressure Negative pressure Pressure state of vacuum canister Atmospheric pressure Atmospheric pressure Medium pressure Medium pressure action LPG begins to be supplied inside the surge tank. Residual LPG from the vacuum canister flows into the surge tank. After the remaining LPG has run out, negative pressure is generated in the canister until just before the solenoid valve closes. LPG is supplied in the surge tank to operate the engine.

According to the present invention described above, even if the engine is stopped, the residual gas flowing into the surge tank can be quickly discharged using a separate negative pressure forming means, thereby maximizing the discomfort felt by the driver or passenger due to the residual gas. .

Claims (2)

An evaporator for reducing the liquid gas (LPG) to vaporize to reduce the vaporization, a mixer for mixing the external air and the vaporized gas flowing through the air cleaner, and an electronic control unit on the gas connection pipe installed between the mixer and the evaporator In the LLP vehicle comprising a solenoid valve installed to open and close the flow path in accordance with the drive signal of the ECU, Residual gas removal means for forming a separate negative pressure for a predetermined time from the moment when the start is stopped between the mixer and the surge tank to prevent the gas remaining in the gas connection pipe between the evaporator and the mixer is introduced into the surge tank so as not to remain. Residual gas removal device of the LLP vehicle, further comprising. The method of claim 1, The residual gas removing means includes a residual gas flow tube additionally installed between the mixer and the surge tank; A vacuum canister installed at the end of the residual gas flow tube to serve as a vacuum storage tank; And a solenoid valve further installed on the gas flow tube to open and close the flow path in accordance with a drive signal of an electronic control unit (ECU).