KR102614319B1 - Method of controlling a fuel pump of LPG liquid injection vehicle - Google Patents

Abstract

A fuel pump control method for an LPG liquid injection vehicle includes setting a section in which the fuel pump provided in the fuel tank of the LPG liquid injection vehicle is forcibly driven by the PCU before being driven by communication between the ECU and the PCU, When the ignition key on signal is confirmed, driving the fuel pump with a constant voltage in the range of 0 to 80% of the maximum voltage of the fuel pump in the fuel pump forced driving section and the fuel pump It may include driving the fuel pump while gradually increasing the voltage of the fuel pump so that the voltage of the fuel pump reaches the maximum voltage in the communication driving section.

Description

Method of controlling a fuel pump of LPG liquid injection vehicle {Method of controlling a fuel pump of LPG liquid injection vehicle}

The present invention relates to a fuel pump control method, and more specifically, to a fuel pump control method during startup in an LPG liquid injection vehicle.

Generally, LPG liquid injection vehicles use a DC motor type or BLDC motor type fuel pump to create high fuel pressure and supply a large flow rate from the fuel tank to the engine. In particular, when the driver turns on the ignition key, the vehicle operates the fuel pump to the maximum for smooth starting. The above vehicle is equipped with an overflow prevention valve (EFV) as required by law.

When fuel is supplied by driving the fuel pump, the overflow prevention valve does not close because the flow rate of the fuel pump is smaller than the differential pressure and flow rate regulated by the law.

However, when the fuel pump is first operated while a pressure difference occurs between the front and rear ends of the overflow prevention valve according to the soaking conditions of the vehicle, there is a possibility that the overflow prevention valve may be closed.

Because the fuel pump continuously supplies the fuel, once the overflow prevention valve is closed, it does not open again while the fuel pump is operating. In this case, only a small amount of fuel is supplied to the engine through the vent hole. Since sufficient fuel is not supplied to the engine, problems such as poor starting, reduced acceleration performance while driving, and engine stop may occur in the vehicle.

The present invention provides a fuel pump control method for an LPG liquid injection vehicle that can prevent malfunction of an overflow prevention valve when starting the LPG liquid injection vehicle.

The fuel pump control method of the LPG liquid injection vehicle according to the present invention includes the steps of setting a section in which the fuel pump provided in the fuel tank of the LPG liquid injection vehicle is forcibly driven by the PCU before being driven by communication between the ECU and the PCU; , when the ignition key on signal of the vehicle is confirmed, driving the fuel pump with a voltage of a constant value lower than the maximum voltage of the fuel pump in the fuel pump forced driving section and the fuel pump communication driving section It may include driving the fuel pump while gradually increasing the voltage of the fuel pump so that the voltage of the fuel pump reaches the maximum voltage.

According to one embodiment of the present invention, the forced driving time by the PCU may be the same as the signal delay time when the ECU and the PCU communicate.

According to embodiments of the present invention, a constant voltage value lower than the maximum voltage of the fuel pump may be 0 to 80% of the maximum voltage.

The method of controlling the fuel pump of an LPG liquid injection vehicle according to the present invention includes the steps of measuring the time required to prevent blocking of the overflow prevention valve by reducing the pressure difference before and after the overflow prevention valve when the fuel pump is operated in the LPG liquid injection vehicle. and setting a section in which the fuel pump is forcibly driven by the PCU before it is driven by communication between the ECU and the PCU based on the measured time, and when the ignition key on signal of the vehicle is confirmed, the fuel pump It may include driving the fuel pump while gradually increasing the voltage of the fuel pump from 0 to reach the maximum voltage of the fuel pump in the forced driving section.

According to one embodiment of the present invention, in the step of forcibly driving the fuel pump, the voltage of the fuel pump may be increased at a constant rate from 0 to the maximum voltage.

According to one embodiment of the present invention, in the step of forcibly driving the fuel pump, the voltage of the fuel pump is kept constant in the range of 0 to less than 80% of the maximum voltage, and then the voltage is maintained constant from the constant voltage. The maximum voltage can be increased at a constant rate of increase.

According to one embodiment of the present invention, in the step of forcibly driving the fuel pump, the voltage of the fuel pump is kept constant at the first voltage, and then the first voltage is changed to a second voltage higher than the first voltage. In the raised state, the voltage can be increased at a constant rate up to the maximum voltage.

According to one embodiment of the present invention, the second voltage may be 80% or less of the maximum voltage.

According to one embodiment of the present invention, the fuel pump control method of the LPG liquid injection vehicle includes driving the fuel pump to maintain the voltage of the fuel pump at the maximum voltage for a predetermined time in a communication drive section of the fuel pump. It may further include.

According to the fuel pump control method of the LPG liquid injection vehicle of the present invention, a section in which the fuel pump is forced to be driven by the PCU is set before the fuel pump is driven by communication between the ECU and the PCU, and the fuel pump is set in the forced drive section. After driving the fuel pump with a voltage of a constant value lower than the maximum voltage of the fuel pump, gradually increase the voltage of the fuel pump so that the voltage of the fuel pump reaches the maximum voltage in the fuel pump communication driving section. The fuel pump can be driven while doing so.

After the fuel pump is driven at a relatively low voltage to form an initial pressure in the fuel line, the voltage applied to the fuel pump is gradually increased to the maximum voltage, so the pressure difference before and after the overflow prevention valve cannot be increased. there is. Accordingly, the overflow prevention valve can be prevented from closing.

In addition, according to the fuel pump control method of the LPG liquid injection vehicle, when the ignition key on signal of the vehicle is confirmed, the voltage of the fuel pump is adjusted from 0 to the maximum voltage of the fuel pump in the fuel pump forced driving section. After driving the fuel pump while gradually increasing, the fuel pump may be driven to maintain the voltage of the fuel pump at the maximum voltage for a certain period of time in the communication drive section of the fuel pump.

In the step of forcibly driving the fuel pump, the maximum voltage is not immediately applied to the fuel pump, but the voltage applied to the fuel pump gradually increases, so the amount of LPG fuel discharged by the fuel pump gradually increases. do. Accordingly, even when the fuel pump is operated, the pressure difference between the front and rear ends of the overflow prevention valve does not increase, and thus the overflow prevention valve can be prevented from closing when the vehicle is started.

In addition, in the step of forcibly driving the fuel pump, the PCU forcibly drives the fuel pump, so when a signal for controlling the fuel pump is transmitted from the ECU to the PCU, the PCU is The operation of the fuel pump can be stably controlled.

Figure 1 is a block diagram for explaining a fuel supply device for an LPG liquid injection vehicle according to an embodiment of the present invention.
2 to 5 are graphs for explaining a fuel pump control method of an LPG liquid injection vehicle according to an embodiment of the present invention.

Hereinafter, a fuel pump control method for an LPG liquid injection vehicle according to an embodiment of the present invention will be described in detail with reference to the attached drawings. Since the present invention can be subject to various changes and can have various forms, specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention. While describing each drawing, similar reference numerals are used for similar components. In the attached drawings, the dimensions of the structures are enlarged from the actual size for clarity of the present invention.

Terms such as first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, a first component may be named a second component, and similarly, the second component may also be named a first component without departing from the scope of the present invention.

The terms used in this application are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless explicitly defined in the present application, should not be interpreted in an ideal or excessively formal sense. No.

Figure 1 is a block diagram for explaining a fuel supply device for an LPG liquid injection vehicle according to an embodiment of the present invention.

Referring to FIG. 1, the fuel supply device 100 for an LPG liquid injection vehicle includes a fuel tank 110, an injector 120, a fuel line 130, a fuel pump 140, an overflow prevention valve 150, and a PCU ( 160) and ECU (170).

The fuel tank 110 stores LPG fuel therein.

The injector 120 is mounted on the intake manifold of the engine in the vehicle and injects the LPG fuel.

The fuel line 130 connects the fuel tank 110 and the injector 120, and supplies the LPG fuel to the injector 120 or recovers the LPG fuel to the fuel tank 110.

The fuel pump 140 is provided in the fuel tank 110 and transfers the LPG fuel in a high-pressure liquid form to the injector 120.

The overflow prevention valve 150 is provided in the fuel line 130 adjacent to the fuel pump 140 or in the middle of the fuel line 130, and when the fuel line 130 is damaged, the LPG fuel in the fuel tank 110 is discharged to the outside. In case of leakage, the fuel line 130 is blocked to prevent leakage of LPG fuel.

The PCU 160 controls the operation of the fuel pump 140. After starting the vehicle, the PCU 160 controls the operation of the fuel pump 140 according to the driving signal of the fuel pump 140 transmitted from the ECU 170. After starting the vehicle, the PCU 160 autonomously controls the operation of the fuel pump 140 before the driving signal for the fuel pump 140 is transmitted from the ECU 170.

The ECU 170 communicates with the PCU 160, and the PCU 160 provides a signal to the PCU 160 to drive the fuel pump 140.

2 to 5 are graphs for explaining a fuel pump control method of an LPG liquid injection vehicle according to an embodiment of the present invention.

Referring to FIG. 2, the fuel pump control method of the LPG liquid injection vehicle is as follows.

First, a section in which the fuel pump 140 provided in the fuel tank 110 of the LPG liquid injection vehicle is forced to be driven by the PCU 160 is set before being driven by communication between the ECU 170 and the PCU 160. .

When the vehicle's ignition key is turned on, the fuel pump 140 is forcibly driven by the PCU 160 and then driven by communication between the ECU 170 and the PCU 160.

The forced drive section is a section for verifying the input signal input from the ECU 170 to the PCU 160. When the ECU 170 and the PCU 160 communicate to verify the input signal, the signal is delayed. Accordingly, the time at which the forced driving is performed by the PCU 160 is substantially the same as the time at which the signal is delayed when the ECU 170 and the PCU 160 communicate. Additionally, the forced driving section may be adjusted according to the time required to verify the input signal, that is, the delay time of the signal.

After the forced drive section is set, when the vehicle's ignition key on signal is confirmed, the fuel pump 140 is driven at a constant voltage lower than the maximum voltage of the fuel pump 140 in the fuel pump forced drive section. At this time, the constant voltage range may be between 0 and about 80% of the maximum voltage of the fuel pump. Preferably, the constant voltage range may range from 0 to about 50% of the maximum voltage of the fuel pump.

When the fuel pump 140 exceeds about 80% of the maximum voltage, the difference between the voltage of the fuel pump 140 and the maximum voltage in the forced driving section is not large. Therefore, when a voltage exceeding about 80% of the maximum voltage is applied to the fuel pump 140 in the forced driving section while a pressure difference occurs between the front and rear ends of the overflow prevention valve 150, the overflow prevention valve 150 ) may malfunction.

When a voltage lower than about 80% of the maximum voltage is applied to the fuel pump 140, the amount of LPG fuel discharged by the fuel pump 140 is relatively small. Accordingly, even if the fuel pump 140 is operated, the pressure difference between the front and rear ends of the overflow prevention valve 150 does not increase, and the overflow prevention valve 150 can be prevented from closing.

In particular, when a voltage lower than about 50% of the maximum voltage is applied to the fuel pump 140, the amount of LPG fuel discharged by the fuel pump 140 is further reduced. Accordingly, the overflow prevention valve 150 can be prevented from closing more reliably.

Additionally, since a voltage lower than about 80% of the maximum voltage is applied to the fuel pump 140, an initial pressure is formed in the fuel line 130 by pumping of the fuel pump 140.

Thereafter, in the communication drive section of the fuel pump 140, the fuel pump 140 is driven while gradually increasing the voltage of the fuel pump 140 so that the voltage of the fuel pump 140 reaches the maximum voltage.

After the initial pressure is formed in the fuel line 130, the voltage applied to the fuel pump 140 is gradually increased to the maximum voltage, so the pressure difference between the front and back of the overflow prevention valve 150 may not increase. Therefore, the overflow prevention valve 150 can be prevented from closing.

Since the overflow prevention valve 150 is prevented from closing, LPG fuel in the fuel tank 110 can be sufficiently supplied to the injector 120. Therefore, it is possible to prevent the vehicle from failing to start, deteriorating acceleration performance while driving, and engine stoppage.

Meanwhile, in the communication drive section of the fuel pump 140, the voltage of the fuel pump 140 is maintained at the maximum voltage for a certain period of time, and when the RPM of the vehicle is stabilized, the voltage of the fuel pump 140 is changed to the idle voltage. change For example, the idle voltage may be about 60 to 80% of the maximum voltage.

Referring to Figures 3 to 5, the fuel pump control method of the LPG liquid injection vehicle is as follows.

First, the time required to prevent blocking of the overflow prevention valve 150 by maintaining or reducing the pressure difference before and after the overflow prevention valve 150 when operating the fuel pump 140 in an LPG liquid injection vehicle is measured.

The time may vary depending on the type of vehicle and can be measured through repeated experiments.

Based on the measured time, a section in which the fuel pump 140 is forcibly driven by the PCU 160 is set before being driven by communication between the ECU 170 and the PCU 160.

When the vehicle's ignition key on signal is confirmed, the fuel pump 140 gradually increases the voltage of the fuel pump 140 from 0 to the maximum voltage of the fuel pump in the forced driving section of the fuel pump 140. Run .

For example, in the step of forcibly driving the fuel pump 140 as shown in FIG. 3, the PCU 160 may increase the voltage of the fuel pump 140 at a constant rate of increase from 0 to the maximum voltage.

As another example, in the step of forcibly driving the fuel pump 140 as shown in FIG. 4, the PCU 160 maintains the voltage of the fuel pump 140 constant in the range of 0 to less than about 80% of the maximum voltage, The voltage can be increased at a constant rate from the constant voltage to the maximum voltage.

Preferably, the voltage of the fuel pump 140 can be kept constant in the range of 0 to less than about 50% of the maximum voltage.

The lower the voltage maintained constant by the fuel pump 140, the lower the amount of LPG fuel discharged by the fuel pump 140, so even if the fuel pump 140 is operated, the pressure at the front and rear ends of the overflow prevention valve 150 Since the difference does not increase, the overflow prevention valve 150 can be prevented from closing.

As another example, in the step of forcibly driving the fuel pump 140 as shown in FIG. 5, the PCU 160 maintains the voltage of the fuel pump 140 constant at the first voltage, and then changes the first voltage to the first voltage. From being raised to a second voltage higher than the voltage, the voltage can be increased at a constant rate of increase up to the maximum voltage.

At this time, the second voltage is about 80% or less of the maximum voltage. Preferably, the second voltage may be about 50% or less. As the second voltage of the fuel pump 140 decreases, the amount of LPG fuel discharged by the fuel pump 140 decreases, so even if the fuel pump 140 is operated, the pressure difference between the front and rear ends of the overflow prevention valve 150 Since it does not increase, the overflow prevention valve 150 can be prevented from closing.

Additionally, since the first voltage must be lower than the second voltage, the first voltage cannot be determined when the second voltage is 0. Therefore, the second voltage must be greater than 0.

Meanwhile, although not shown, in the step of forcibly driving the fuel pump 140, the PCU 160 may increase the voltage of the fuel pump 140 in a stepwise manner from 0 to the maximum voltage.

As described above, in the step of forcibly driving the fuel pump 140, the maximum voltage is not immediately applied to the fuel pump 140, but the voltage applied to the fuel pump 140 is gradually increased, so the fuel pump 140 The amount of LPG fuel discharged gradually increases. Accordingly, even if the fuel pump 140 is operated, the pressure difference between the front and rear ends of the overflow prevention valve 150 does not increase, and thus the overflow prevention valve 150 can be prevented from closing when the vehicle is started.

Thereafter, the fuel pump 140 is driven to maintain the voltage of the fuel pump 140 at the maximum voltage for a certain period of time during the communication drive section of the fuel pump 140.

Even if the maximum voltage is applied to the fuel pump 140 in the step of forcibly driving the fuel pump 140, the overflow prevention valve 150 is not blocked, so the fuel pump 140 is not blocked in the communication drive section of the fuel pump 140. Even if the voltage is maintained at the maximum voltage for a certain period of time, the overflow prevention valve 150 does not close.

Since the overflow prevention valve 150 is prevented from closing, LPG fuel in the fuel tank 110 can be sufficiently supplied to the injector 120. Therefore, it is possible to prevent the vehicle from failing to start, deteriorating acceleration performance while driving, and engine stoppage.

When a signal for controlling the fuel pump 140 is transmitted from the ECU 170 to the PCU 160, the signal is delayed. However, since the PCU 160 forcibly drives the fuel pump 140 in the step of forcibly driving the fuel pump 140, the PCU 160 drives the fuel pump 140 regardless of the signal delay phenomenon. You can control it.

Meanwhile, in the communication drive section of the fuel pump 140, the voltage of the fuel pump 140 is maintained at the maximum voltage for a certain period of time, and when the RPM of the vehicle is stabilized, the voltage of the fuel pump 140 is changed to the idle voltage. change For example, the idle voltage may be about 60 to 80% of the maximum voltage.

As described above, the method of controlling the fuel pump of an LPG liquid injection vehicle according to the present invention gradually increases the voltage applied to the fuel pump to the maximum voltage when starting the vehicle, thereby preventing the overflow prevention valve from being blocked. . Therefore, LPG fuel in the fuel tank can be sufficiently supplied to the injector. Therefore, it is possible to prevent the vehicle from failing to start, deteriorating acceleration performance while driving, and engine stoppage.

Although the present invention has been described above with reference to preferred embodiments, those skilled in the art can make various modifications and changes to the present invention without departing from the spirit and scope of the present invention as set forth in the following patent claims. You will understand that it is possible.

100: Fuel supply device for LPG liquid injection vehicle
110: fuel tank 120: injector
130: fuel line 140: fuel pump
150: Overflow prevention valve 160: PCU
170:ECU

Claims (1)

Setting a section in which the fuel pump provided in the fuel tank of the LPG liquid injection vehicle is forcibly driven by the PCU before being driven by communication between the ECU and the PCU;
When the ignition key on signal of the vehicle is confirmed, driving the fuel pump at a constant voltage lower than the maximum voltage of the fuel pump in the fuel pump forced driving section; and
A fuel pump for an LPG liquid injection vehicle, comprising the step of driving the fuel pump while gradually increasing the voltage of the fuel pump so that the voltage of the fuel pump reaches the maximum voltage in the fuel pump communication driving section. Control method.

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