KR20110033476A - Regulator for compressed natural gas vehicle having leakage fuel gas detecting and collecting functions - Google Patents

Abstract

PURPOSE: A regulator for a compressed natural gas vehicle with leaked gas fuel sensing and collecting functions is provided to ensure stability since a simple part is installed and a structure is improved so that the failure of an engine due to the leaked gas fuel from the regulator is prevented. CONSTITUTION: A regulator for a compressed natural gas vehicle with leaked gas fuel sensing and collecting functions comprises a body(10), a connecting pipe(30), a flow rate sensor(40) and a canister(50). The body comprises a diaphragm, a spring and a valve assembly. The body decompresses high-pressure gas fuel to discharge it at a given pressure. The connecting pipe connects the upper space of the diaphragm to an intake manifold(20). The connecting pipe makes the pressure of the intake manifold act onto the diaphragm. The flow rate sensor is installed on the connecting pipe and senses the flow rate of leaked gas fuel if the gas fuel is leaked due to the damage to the diaphragm.

Description

REGULATOR FOR COMPRESSED NATURAL GAS VEHICLE HAVING LEAKAGE FUEL GAS DETECTING AND COLLECTING FUNCTIONS}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressed natural gas vehicle, and more particularly, to a regulator for reducing a high pressure gas fuel to a low pressure to provide an engine injector.

In compressed natural gas (CNG) vehicles, the basic structure of the engine is the same as that of diesel engines and differs in fuel system. Compressed natural gas, which is a fuel, is stored in a gas container in a vehicle in a gaseous state or in a thermal insulation container in a liquefied state. The stored gaseous fuel is supplied to the regulator via a fuel pipe, reduced in pressure by a constant pressure in the regulator, mixed with air in the injector, and supplied into the engine.

In order to achieve a precise fuel supply in a compressed natural gas vehicle, the pressure and temperature of the fuel supplied to the injector must be maintained within the allowable value regardless of the change in fuel flow rate and pressure condition. Although the fuel control unit (ECU) is designed to calibrate the injection volume by measuring the pressure and temperature of the fuel, excessive departures cause misfire or abnormal combustion beyond the limits of calibration.

The regulator must therefore be designed to maintain the pressure and temperature of the fuel within tolerances under any operating conditions. However, when the diaphragm inside the regulator is damaged and gas fuel leaks, the leaked gas fuel is continuously discharged to the intake manifold. If this phenomenon persists, there is a problem that the rotation speed of the engine increases or knocking occurs.

The present invention is to provide a compressed natural gas vehicle regulator that detects, collects and diagnoses a leaked gas fuel when the gas fuel leaks due to diaphragm damage.

Compressed natural gas vehicle regulator according to an embodiment of the present invention, iii) a diaphragm, a spring and a valve assembly, a regulator main body for decompressing the high-pressure gas fuel flowing into a constant pressure, ii) the upper space of the diaphragm And a flow detector which connects the intake manifold so that the pressure of the intake manifold acts on the diaphragm, i) a flow pipe that detects the flow rate of the leaked gas fuel when the gas fuel leaks due to the diaphragm damage. It is installed in the connection pipe and includes a canister that operates when gas fuel leaks and collects leaked gas fuel.

The canister may include a housing filled with activated carbon in the inner space, an inlet port and an outlet port installed between the connection pipe and the housing, an on / off valve installed at the inlet port, and a purge control solenoid valve installed at the outlet port. .

The compressed natural gas vehicle regulator further includes a control unit electrically connected to the flow detector and the canister, and the control unit may generate a failure diagnosis signal when the continuous flow of the leaked gas fuel is detected at the flow detector.

The control unit may generate a fault diagnosis signal when the flow rate of the leaked gas fuel detected by the flow detector exceeds a correction range of the injector injection amount, and open the inlet port to allow the canister to collect the leaked gas fuel. The controller may repeat the process of collecting the leaked gas fuel of the canister by opening the inlet port under the idle driving condition and discharging the collected gas fuel by opening the discharge port.

On the other hand, the control unit generates a fault diagnosis signal when the flow rate of the leaked gas fuel detected by the flow sensor exceeds the correct range of the injector injection amount under vehicle driving conditions, and releases the trapped gas fuel by opening the discharge port. Can be initialized.

According to one embodiment of the present invention, it is possible to suppress the abnormal operation of the engine due to the gas fuel leaked from the regulator by the simple installation and improvement of the structure. Therefore, it is possible to secure the stability of the engine and to provide fault diagnosis information to the driver.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

1 is a block diagram of a regulator for a compressed natural gas vehicle according to an embodiment of the present invention, Figure 2 is a cross-sectional view of the regulator body shown in FIG.

1 and 2, the regulator 100 for a compressed natural gas vehicle according to the present embodiment includes a spring 11, a diaphragm 12, and a valve assembly 13, and includes a regulator body 10 for reducing a high-pressure gas fuel. ), A connecting pipe 30 for connecting the upper space of the diaphragm 12 and the intake manifold 20, and a flow sensor 40 and a canister 50 installed in the connecting pipe 30.

Inside the regulator body 10, a gas inlet 14 through which high-pressure gas fuel is introduced, a spring 11 for reducing gas fuel, a diaphragm 12, a valve assembly 13, and a reduced pressure gas A gas outlet 15 through which the fuel is discharged, and a coolant accommodating part 16 for circulating high temperature coolant to generate heat exchange with the gas fuel.

The gas inlet 14, the valve assembly 13, and the gas outlet 15 are located at the center of the regulator body 10, the spring 11 and the diaphragm 12 are located at the top of the regulator body 10, and the coolant is The receiving portion 16 is located below the regulator body 10.

The gas fuel of high pressure (approximately 200 bar to 20 bar) supplied to the gas inlet 14 is reduced to low pressure (approximately 6.8 bar to 8.7 bar) while passing through the valve 17 and then to the injector of the engine via the gas outlet 15. Supplied. When the high pressure gas fuel expands under reduced pressure to a low pressure, a sudden temperature drop occurs, thereby exchanging the high temperature engine coolant and the gas fuel to suppress a sudden temperature drop and freezing of the gas fuel.

The diaphragm 12 senses pressure and serves to determine the position of the valve 17 together with the force of the spring 11. The upper space of the diaphragm 12 is connected to the intake manifold 20 through a connecting pipe 30. As a result, a low intake manifold pressure acts on the diaphragm 12 in a low fuel state with low fuel, and a relatively high intake manifold pressure acts on the diaphragm 12 in a heavy fuel state.

Therefore, the drop effect caused by the change in the flow rate of the gas fuel at a constant supply pressure condition is reduced, so that the pressure of the gas fuel supplied to the injector can be kept relatively constant.

However, when the diaphragm 12 is damaged, gas fuel leaks into the upper space of the diaphragm 12, and the leaked gas fuel is continuously discharged to the intake manifold 20. If this phenomenon continues, the engine speed increases or knocking occurs. When the engine is stopped, the fuel is cut off by the operation of the cut-off solenoid valve and is safe. However, when the engine is stopped, the engine controllability and driving safety are adversely affected.

The flow rate sensor 40 installed in the connection pipe 30 detects the flow rate of the gas when the fuel leaks. That is, in the normal state in which the diaphragm 12 is not damaged, the pressure change due to the change in the intake pressure occurs in the connecting pipe 30, and does not show the flow of gas fuel. However, when gas fuel leaks due to damage to the diaphragm 12, a continuous flow appears in the intake manifold 20, and the flow rate sensor 40 detects the flow rate of the leaked gas fuel.

The flow sensor 40 and the canister 50 are electrically connected to the control unit 60. When the flow rate sensor 40 detects the continuous flow of the leaked gas fuel, the controller 60 recognizes a failure of the regulator body 10 and generates a failure diagnosis signal, and provides the driver with a failure diagnosis signal. The controller 60 controls the operation of the canister 50 so that the leaked gas fuel may be introduced into the intake manifold 20 or may be collected by the canister 50.

The canister 50 includes a housing 51 filled with activated carbon in the inner space, an inlet port 52 and an outlet port 53 installed between the connection pipe 30 and the housing 51. The inlet port 52 is provided with an on-off valve 54, the outlet port 53 is provided with a purge control solenoid valve 55 that operates by sensing the pressure. The on-off valve 54 operates at the command of the control unit 60. Activated carbon adsorbs the leaked gas fuel provided as a porous structure and releases the adsorbed gas fuel when the discharge port 53 is opened.

Next, the operation of the regulator 100 in the idle driving conditions and the vehicle driving conditions will be described.

First, in the idle operation condition, since the capacity of the gas fuel that can be collected in the canister 50 is not large, when the initial leakage occurs, the leaked gas fuel is discharged directly to the intake manifold 20, and the injector is controlled by a known lambda feedback control. Injection volume correction stabilizes engine operation.

If the flow rate of the leaked gas fuel sensed by the flow sensor 40 exceeds the range of injector injection amount correction, the control unit 60 operates the on / off valve 54 of the canister 50 to open the inlet port 52. To allow leakage gas fuel to be collected in the canister 50. At the same time, the controller 60 generates a fault diagnosis signal and provides it to the driver.

When the leaked gas fuel is collected in the canister 50 and the pressure in the canister 50 exceeds the set value, the purge control solenoid valve 55 operates to open the discharge port 53. Then, the leaked gas fuel adsorbed on the activated carbon is released to the intake manifold 20 through the discharge port 53 and the connection pipe 30.

In this manner, in the idle driving condition, a fault diagnosis signal is provided to the driver, and the process of collecting and discharging the leaked gas fuel using the canister 50 is repeated until the fault is repaired.

Next, in the vehicle driving condition, since continuous output is required from the engine, the leaked gas fuel is directly provided to the intake manifold 20, and the operation of the engine is stabilized by correcting the injection amount of the injector. When the flow rate sensor 40 detects the leakage of the gas fuel, the controller 60 generates a failure diagnosis signal and provides it to the driver.

Under vehicle driving conditions, the leaked gas fuel is not collected in the canister 50. If the leaked gas fuel is collected inside the canister 50 by sensing the control unit 60, the discharge port 53 is opened to discharge the collected gas fuel. Let's do it. Therefore, the canister 50 is returned to the initial state to create a collection condition in the idle driving conditions.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the range of.

1 is a block diagram of a compressed natural gas vehicle regulator according to an embodiment of the present invention.

2 is a cross-sectional view of the regulator body shown in FIG. 1.

Claims (6)

A regulator body having a diaphragm, a spring, and a valve assembly, and configured to reduce a high-pressure gas fuel flowing therein and discharge the gas at a predetermined pressure; A connecting pipe connecting the upper space of the diaphragm with the intake manifold so that the pressure of the intake manifold acts on the diaphragm; A flow rate sensor installed at the connection pipe and detecting a flow rate of the leaked gas fuel when the gas fuel leaks due to damage of the diaphragm; And And a canister installed at the connection pipe and operating when the gas fuel leaks to collect the leaked gas fuel. The method of claim 1, The canister includes a housing filled with activated carbon in an inner space, an inlet port and an outlet port installed between the connection pipe and the housing, an opening / closing valve installed in the inlet port, and a purge control solenoid valve installed in the outlet port. Compressed natural gas vehicle regulator comprising. The method of claim 2, And a control unit electrically connected to the flow rate detector and the canister, wherein the control unit generates a failure diagnosis signal when the continuous flow of the leaking gas fuel is detected by the flow rate detector. The method of claim 3. The control unit generates the fault diagnosis signal when the flow rate of the leaked gas fuel detected by the flow rate sensor exceeds the correction range of the injector injection amount, and opens the inlet port so that the canister captures the leaked gas fuel. Regulator for gas vehicles. The method of claim 4, wherein And the control unit repeats the leakage gas fuel collection of the canister by the opening of the inlet port and the discharge of the collection gas fuel by the opening of the discharge port under idle driving conditions. The method of claim 3, The control unit generates the fault diagnosis signal when the flow rate of the leaked gas fuel sensed by the flow sensor exceeds a correction range of the injector injection amount in a vehicle driving condition, and releases the collected gas fuel by opening the discharge port. Compressed natural gas vehicle regulator to initialize the.

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