KR20160072588A - Fuel level management apparatus and method of cng vehicle - Google Patents

Abstract

The present invention comprises: a pressure sensor detecting pressure of fuel stored in a compressed natural gas (CNG) fuel tank; a temperature sensor detecting a temperature of the fuel stored in the CNG fuel tank; and a fuel level measurement unit calculating the number of moles inside the CNG fuel tank by using the pressure and the temperature which are respectively detected by the pressure sensor and the temperature sensor, and displaying a residual fuel level through an output unit after calculating the residual fuel level of the fuel based on the calculated number of moles.

Description

TECHNICAL FIELD [0001] The present invention relates to a fuel management system for a CNG fuel vehicle,

The present invention relates to an apparatus and a method for managing the fuel amount of a CNG fuel vehicle, and more particularly, to an apparatus and method for managing a fuel amount of a CNG fuel vehicle, And more particularly, to an apparatus and a method for managing a fuel amount of a CNG fuel vehicle.

The fuel of the vehicle uses gasoline or gas, and in particular, one of compressed natural gas (CNG) or liquefied propane gas (LPG) is used as the gaseous fuel.

In the case of an automobile that drives an engine using CNG fuel among gaseous fuels, high pressure CNG is stored in the fuel tank.

For vehicles using CNG as a fuel, the volume of the container storing the CNG fuel is used as the volume and used as the mass when the CNG is charged. However, the amount of state that receives information on CNG fuel in the vehicle corresponds to the pressure. As a result, in the conventional CNG vehicle system, the information about the degree of the fuel in the tank was roughly grasped based on the pressure.

However, since the pressure corresponds to the amount of state in which the CNG corresponding to the vapor fuel can change according to the environment such as the temperature, it may lack accuracy in simply using the pressure as an index for the residual fuel amount.

The background art of the present invention is disclosed in Korean Patent Laid-Open Publication No. 10-1998-0022008 (Jun. 25, 1998).

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for measuring the amount of methane in a tank based on the pressure and temperature of a CNG fuel tank, And a method for managing the fuel amount of a CNG fueled vehicle.

Another object of the present invention is to provide an apparatus and method for managing the fuel amount of a CNG fuel vehicle which improves the accuracy and reliability of the residual fuel amount and the travelable distance by calculating the remaining fuel amount and the travelable distance with the mass corresponding to the state high flow rate of the CNG fuel .

It is still another object of the present invention to provide a CNG fueling vehicle capable of detecting a fuel leak on a CNG fuel vehicle on the basis of an actual injection amount to determine a fuel leak relatively accurately and displaying a judgment result to a driver so that a driver can positively cope with a fuel leak. Fuel ratio control apparatus and method.

According to an aspect of the present invention, there is provided an apparatus for managing a fuel amount of a CNG vehicle, including: a pressure sensor for sensing a pressure of fuel stored in a CNG (Compressed Natural Gas) fuel tank; A temperature sensor for sensing the temperature of the fuel stored in the CNG fuel tank; And calculating the number of moles in the CNG fuel tank by using the pressure and temperature sensed by the pressure sensor and the temperature sensor, calculating the remaining fuel amount of the fuel based on the calculated number of moles, And a fuel amount measuring unit for displaying the fuel amount.

The present invention is characterized by further comprising a travel distance calculation unit for calculating the travelable distance by multiplying the residual fuel amount measured by the fuel amount measurement unit by the average fuel mileage calculated in advance and expressing the travelable distance through the output unit.

The present invention relates to an injection amount measuring apparatus for measuring an injection amount actually injected through an injector for a predetermined period of time; And a fuel leakage judging unit for judging whether or not the fuel is leaked in accordance with the fuel amount obtained by subtracting the injection amount measured by the injection amount measuring unit from the residual injection amount measured at the previous time point before the predetermined time and the residual fuel amount measured by the fuel amount measuring unit And further comprising:

In the present invention, the fuel leakage judging unit may judge whether or not the first fuel injection amount between the fuel amount obtained by subtracting the injection amount measured by the injection amount measuring unit and the residual fuel amount measured by the fuel amount measuring unit from the residual injection amount measured at the previous time, And determines whether or not the fuel leakage occurs if the error is equal to or greater than the first threshold value.

In the present invention, when the fuel amount obtained by subtracting the injection amount measured by the injection amount measuring unit from the residual injection amount measured at a previous time before the predetermined measurement time exceeds the residual fuel amount measured by the fuel amount measuring unit Fuel leakage is determined.

In the present invention, the fuel leakage determination unit may subtract a fuel amount obtained by subtracting the injection amount measured by the injection amount measurement unit from the fuel amount measured at the advantage point, from the residual injection amount measured at the time when a predetermined set time has elapsed, And determines that the fuel leaks if the second error is increased by a second threshold value that is greater than the first error by a predetermined value.

A method for managing a fuel amount of a CNG fuel vehicle according to an aspect of the present invention includes: calculating a number of moles of a CNG fuel tank using a fuel pressure and a temperature stored in a CNG (Compressed Natural Gas) fuel tank; Calculating a remaining fuel amount of the fuel based on the calculated number of moles of the fuel amount measuring unit; And exposing the residual fuel amount to the fuel amount measuring unit through an output unit.

The present invention is characterized in that the step of measuring the injected amount of injected fuel injected through the injector for a predetermined period of time comprises: And a fuel leak amount judging unit that judges whether or not the fuel leakage is caused according to the fuel amount obtained by subtracting the injection amount measured by the injection amount measuring unit from the residual injection amount measured at the previous time point before the fuel leak judging unit has been set a predetermined time and the residual fuel amount measured by the fuel amount measuring unit The method comprising the steps of:

The present invention is a fuel injection control apparatus for a fuel injection control system for an internal combustion engine, wherein the fuel leakage determination unit determines the fuel injection amount of the first fuel injection amount between the remaining fuel injection amount measured by the fuel injection amount measurement unit and the residual fuel amount measured by the fuel injection amount measurement unit And determining whether the fuel is leaking if the error is equal to or greater than the first threshold value.

When the amount of fuel obtained by subtracting the injection amount measured by the injection amount measuring unit from the residual injection amount measured at a previous time before the fuel leak determining unit has been set to a predetermined measurement time exceeds the residual fuel amount measured by the fuel amount measuring unit And judging the fuel leakage as a fuel leak.

The present invention is characterized in that the fuel injection amount determining section subtracts the injection amount measured by the injection amount measuring section from the fuel injection amount measured at the advantage point in the residual injection amount measured at the time when the fuel leak determination section has elapsed after a predetermined set time elapses, And determining that the fuel leaks if the second error is increased by at least a second threshold value set before the first error by a predetermined amount.

The present invention calculates the number of moles of methane in the tank based on the pressure and temperature of the CNG fuel tank, measures the amount of residual fuel based on the number of moles of the methane, converts the amount of residual fuel into the amount of fuel remaining in the CNG tank, So that reliability can be improved.

The present invention detects a fuel leak in a CNG fueled vehicle on the basis of an actual injection amount, judges a fuel leak relatively accurately, and displays a judgment result to a driver so that a driver can positively cope with a fuel leak.

1 is a block diagram of an apparatus for managing fuel amount of a CNG fuel vehicle according to an embodiment of the present invention.
2 is a flowchart of a fuel amount management method of a CNG fueled vehicle according to an embodiment of the present invention.
3 is a flowchart illustrating a fuel leak determination process according to an embodiment of the present invention.

Hereinafter, an apparatus and method for managing a fuel amount of a CNG fueled vehicle according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this process, the thicknesses of the lines and the sizes of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. Further, the terms described below are defined in consideration of the functions of the present invention, which may vary depending on the user, the intention or custom of the operator. Therefore, definitions of these terms should be made based on the contents throughout this specification.

1 is a block diagram of an apparatus for managing fuel amount of a CNG fuel vehicle according to an embodiment of the present invention.

Referring to FIG. 1, a fuel amount management device for a CNG fuel-economy vehicle according to an embodiment of the present invention includes a pressure sensor 10, a temperature sensor 20, a fuel amount measurement unit 30, a travel distance calculation unit 40, A fuel leak determination unit 60, and an output unit 70. The fuel cell 10 includes a fuel cell 10,

The pressure sensor 10 senses the pressure of the fuel stored in a CNG (Compressed Natural Gas) fuel tank (not shown). Here, the CNG fuel tank stores the internal fuel in a pressurized state.

The temperature sensor 20 senses the temperature of the fuel stored in the CNG fuel tank.

For reference, the fuel sensed by the pressure sensor 10 and the temperature sensor 20 may correspond to the pressure and temperature of methane. Generally, the composition of CNG fuel is not a constituent of a single element of methane, but methane accounts for more than 90% of the composition.

The fuel amount measuring unit 30 measures the amount of residual fuel remaining in the CNG fuel tank by using the pressure of the fuel detected by the pressure sensor 10 and the temperature of the fuel measured by the temperature sensor 20. [

More specifically, the fuel amount measuring unit 30 detects the state information of the CNG fuel tank that has been preset when the pressure and temperature of the fuel are detected from the pressure sensor 10 and the temperature sensor 20, respectively, as described above . Here, the state information of the CNG fuel tank may include all the information applied to the Van der Waals equation using the pressure and temperature of the methane.

에 대입하여 메탄의 몰 수를 계산한다. 여기서, 반 데르 발스 방정식의 P는 실린더(미도시) 내부의 메탄의 압력이고, n은 실린더 내부의 메탄의 총 몰수이며, V는 CNG 연료 차량에 설정된 실린더의 전체 부피이며, R은 메탄 가스의 상수로서 0.0821L.atm/mol.k이며, T는 온도 센서(20)에 의해 측정된 CNG 연료 탱크 내부의 온도로서 켈빈온도로 변환된 값이며, a와 b는 반 데르 발스 상수로서 각각 2.283과 0.04278이다. That is, the fuel amount measuring unit 30 measures the pressure, temperature, and state information of the methane by the Van der Waals equation

To calculate the number of moles of methane. Here, P in the van der Waals equation is the pressure of methane in the cylinder (not shown), n is the total number of moles of methane in the cylinder, V is the total volume of the cylinder set in the CNG fuel vehicle, 0.0821 L.atm / mol.k as a constant, T is the temperature inside the CNG fuel tank measured by the temperature sensor 20 and converted to Kelvin temperature, and a and b are van der Waals constants of 2.283 0.04278.

The fuel amount measuring unit 30 calculates the mass of the CNG fuel inside the CNG tank, that is, the residual fuel amount, by multiplying the molar mass calculated by the van der Waals equation as described above by the molar mass.

Then, the fuel amount measuring unit 30 converts the residual fuel amount of the CNG fuel so that it can be expressed by the dashboard information such as clusters of the output unit 70 and the like, and exposes through the output unit 70.

The mileage calculation unit 40 calculates a mileageable distance corresponding to the residual fuel amount by multiplying the average fuel mileage (km / kg) calculated based on the residual fuel amount measured by the fuel amount measurement unit 30 described above.

The injection amount measuring section 50 measures an actual injection amount actually injected into a cylinder (not shown) through an injection (not shown) in the engine control logic.

More specifically, the injection amount measuring unit 50 measures the actual injection amount by accumulating the injection amount of fuel injected for a predetermined time, which can be calculated by the following equation (1).

Here, the relative fuel mass [%] is a value relative to the standard state as a value for the fuel injection amount [%] to be injected from the air amount. For example, relative air mass [%] of a relative fuel mass [%] is 100 [%], which corresponds to the amount of air that can be absorbed at a maximum of 273 K, 1 atm and is a relative value The amount of air to be expressed. Here, the relative fuel mass [%] can be corrected by factors such as supplied fuel pressure, temperature, intake pressure, and the like.

The fuel leakage determination unit 60 calculates the fuel amount by subtracting the injection amount measured by the injection amount measurement unit 50 from the residual injection amount measured at the previous time point before the predetermined time and outputs the fuel amount to the fuel amount measurement unit 30 ) To determine the fuel leakage according to the result of the comparison.

In this case, the fuel leakage judging unit 60 judges whether or not the fuel amount measured by the fuel amount measuring unit 30, which is the fuel amount after subtracting the injection amount measured by the injection amount measuring unit 50 from the residual injection amount measured at the previous time before the preset time If the first error between the remaining fuel amounts is equal to or greater than the first threshold value, it is determined whether or not the fuel leakage occurs.

At this time, the fuel leakage determination unit 60 determines whether or not the remaining fuel amount measured by the fuel amount measurement unit 30 and the remaining fuel injection amount measured at the previous point in time before the predetermined time are subtracted from the fuel injection amount measured by the fuel injection amount measurement unit 50 The fuel amount is compared, and the fuel leakage is outputted through the output unit 70 according to the comparison result.

The fuel leakage determination unit 60 determines the fuel leakage based on the first error as described above. Then, the fuel leakage determination unit 60 determines the fuel leakage based on the remaining fuel injection amount measured at the advantage point The fuel amount obtained by subtracting the injection amount measured by the injection amount measuring section 50 from the fuel amount, and detects the second error, and compares the detected second error with the first error. At this time, if the second error is increased more than the first error by a predetermined second threshold or more, the fuel leakage determination unit 60 determines that a relatively large amount of fuel leaks.

The output unit 70 outputs the fuel remaining amount, the travelable distance, and the fuel leak determination result as described above. As the output unit 70, a cluster or the like provided inside the vehicle may be employed.

Hereinafter, a fuel amount management method of a CNG fueled vehicle according to an embodiment of the present invention will be described in detail with reference to FIGS. 2 and 3. FIG.

FIG. 2 is a flowchart of a fuel amount management method of a CNG fueled vehicle according to an embodiment of the present invention, and FIG. 3 is a flowchart illustrating a fuel leak determination process according to an embodiment of the present invention.

2, first, the pressure sensor 10 senses the pressure of fuel stored in the CNG fuel tank (S10), and the temperature sensor 20 detects the pressure of fuel stored in the CNG fuel tank (S20).

에 대입하여 연료의 몰 수를 계산한다(S30). When the pressure and temperature inside the CNG fuel tank are sensed by the pressure sensor 10 and the temperature sensor 20, the state information of the preset CNG fuel tank is detected, and the pressure, temperature, Wals equation

And the number of mols of fuel is calculated (S30).

Then, the fuel amount measuring unit 30 calculates the residual fuel amount of the CNG fuel inside the CNG tank by multiplying the molar mass by the molar mass calculated through the Van der Waals equation as described above (S40).

When the remaining fuel amount in the CNG fuel tank is measured as described above, the fuel amount measuring unit 30 converts the residual fuel amount of the CNG fuel to be displayed as the instrument panel information such as clusters of the output unit 70, 70) (S50).

The travel distance calculation unit 40 calculates the travelable distance corresponding to the residual fuel amount by multiplying the residual fuel amount measured by the fuel amount measurement unit 30 by the average fuel mileage (km / kg) calculated on the basis of the average fuel mileage The travelable distance is displayed through the output unit 70 (S60).

Next, the injection amount measuring section 50 measures the actual injection amount actually injected into the cylinder through the injection from the engine control logic. In this case, the fuel leakage determination unit 60 determines whether the fuel is leaking using the actual injection amount measured by the injection amount measurement unit 50 (S70).

That is, the fuel leakage determining section 60 is the fuel amount measuring section 30 to the residual fuel quantity (m _{t_current)} from, a predetermined time injection amount in the previous previous residual injection quantity (m _{t_old)} measured in the time measuring section (50 measured by (M _{t_old-} m _c ), which is obtained by subtracting the fuel injection amount m _c measured by the fuel injection amount control means (m _{t_old-} m _c ) Based on the result of the fuel leakage process.

As a result of the determination in step S70, if the first error exceeds the predetermined first threshold value, the fuel leakage determination unit 60 determines that the fuel injection amount m _{t_old)} the injection quantity (m _c) a quantity of fuel (m _{t_old} -m _c) the remaining amount of fuel (m _{t_current)} measured by the above-described fuel quantity measurement section 30, less the quantity measured by the measuring section 50 at the When determining whether or not more than, and (S710), it determined that the fuel quantity (m _{t_old} -m _c) exceeds the residual fuel quantity (m _{t_current)} is determined by the fuel leak (S720).

If the set time has elapsed, the fuel leakage determining unit 60 determines whether the set time has elapsed (S730). If the set time has elapsed, the fuel leakage determining unit 60 determines the remaining fuel injection amount (m _{t_current} ) in the second error by subtracting the net of the injection quantity (m _c) determined by the fuel injection quantity measurement unit 50 from the (m _{t_old)} measured in the above-described advantages point fuel quantity (m _{t_current t_old} -m -m _c) And determines whether the detected second error m _{t_current-} m _{t_old-} m _c has increased by a second predetermined value or more than the first error in step S740.

If it is determined in step S740 that the second error is greater than the first error by the second threshold value, it is determined that a relatively large amount of fuel leaks.

The output unit 70 outputs the determination result of the fuel leakage determination unit 60 (S80) whenever the fuel leakage determination unit 60 determines whether or not the fuel is leaked.

Thus, the present embodiment calculates the number of moles of methane in the tank based on the pressure and the temperature of the CNG fuel tank, calculates the residual fuel amount based on the number of moles, converts the residual fuel amount into the remaining fuel amount in the CNG tank, Thereby improving the accuracy and reliability.

The present embodiment also detects the fuel leakage in the CNG fuel-fueled vehicle on the basis of the actual injection amount, judges the fuel leakage relatively accurately, and displays the judgment result to the driver so that the driver can positively cope with the fuel leakage.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, I will understand. Accordingly, the true scope of the present invention should be determined by the following claims.

10: Pressure sensor
20: Temperature sensor
30: fuel amount measuring unit
40: mileage calculation unit
50:
60: Fuel leak judgment unit
70:

Claims (11)

A pressure sensor for sensing the pressure of the fuel stored in the CNG (Compressed Natural Gas) fuel tank;
A temperature sensor for sensing the temperature of the fuel stored in the CNG fuel tank; And
Calculating the number of moles in the CNG fuel tank by using the pressure and temperature sensed by the pressure sensor and the temperature sensor, calculating the remaining fuel amount of the fuel based on the calculated number of mols, And a fuel amount measurement unit for measuring the fuel amount of the CNG vehicle.
2. The CNG fueling control device according to claim 1, further comprising a travel distance calculating unit for calculating a travelable distance by multiplying the residual fuel amount measured by the fuel amount measuring unit by the average fuel mileage calculated in advance, Fuel ratio.
The method according to claim 1,
An injection quantity measuring unit for measuring an actual injection quantity through the injector for a preset time; And
A fuel leakage judging unit for judging whether or not the fuel is leaked according to the fuel amount obtained by subtracting the injection amount measured by the injection amount measuring unit from the residual injection amount measured at a previous time before the preset time and the residual fuel amount measured by the fuel amount measuring unit Further comprising a control unit for controlling the fuel amount of the CNG fueled vehicle.
4. The fuel cell system according to claim 3, wherein the fuel leakage determination unit
When the first error between the fuel amount obtained by subtracting the injection amount measured by the injection amount measuring section and the residual fuel amount measured by the fuel amount measuring section from the residual injection amount measured at a previous time before the predetermined time is equal to or greater than the first threshold value, Fuel ratio of the CNG fueled vehicle.
5. The fuel cell system according to claim 4, wherein the fuel leakage determination unit
When the amount of fuel, which is obtained by subtracting the injection amount measured by the injection amount measuring unit, from the residual injection amount measured at a previous time before the predetermined measurement time exceeds the residual fuel amount measured by the fuel amount measuring unit CNG fuel vehicle fuel management device.
6. The fuel cell system according to claim 5, wherein the fuel leakage determination unit
A second error is detected by subtracting the fuel amount obtained by subtracting the injection amount measured by the injection amount measuring section from the fuel amount measured at the advantage point in the residual injection amount measured at the time when the predetermined set time has elapsed, And determines that the fuel leaks if the first error is increased beyond a second threshold value that is set before the first error.
Calculating a number of moles inside the CNG fuel tank using the pressure and temperature of the fuel stored in the CNG (Compressed Natural Gas) fuel tank;
Calculating a remaining fuel amount of the fuel based on the calculated number of moles of the fuel amount measuring unit; And
And displaying the remaining amount of fuel through the output unit.
8. The method of claim 7,
Measuring an injection amount measured by the injection amount measuring unit through the injector for a preset time; And
Fuel leakage is determined according to the fuel amount obtained by subtracting the injection amount measured by the injection amount measuring unit from the residual injection amount measured at the previous time point before the fuel leak determination unit has been set and the residual fuel amount measured by the fuel amount measuring unit Further comprising the step of: determining a fuel amount of the CNG fueled vehicle.
The fuel injection control device according to claim 8, further comprising: a fuel injection amount calculation unit for calculating a fuel injection amount based on the fuel injection amount, And determining whether or not the fuel leakage occurs if the first error is equal to or greater than the first threshold value.
10. The fuel injection amount estimating apparatus according to claim 9, wherein the fuel leakage amount determining unit determines the fuel amount obtained by subtracting the injection amount measured by the injection amount measuring unit from the residual injection amount measured at a previous time before the predetermined measurement time, And if it is determined that the fuel leakage is excessive, determining that the fuel leakage is excessive.
11. The fuel injection control device according to claim 10, wherein the remaining fuel injection amount measured at a point in time at which the fuel leak determination section has elapsed after a predetermined set time elapses is calculated by subtracting the fuel amount obtained by subtracting the injection amount measured by the injection amount measurement section from the fuel amount measured at the advantage point Detecting a second error and determining that the fuel leaks if the second error is increased by at least a second threshold value set beforehand by a first error.

Images