KR102296562B1 - Pressure regulator apparatus for fuel rail of GDI Gasoline engine in Gasoline-Gas bi-fuel engine system - Google Patents

Abstract

The present invention relates to a high-pressure fuel rail pressure control apparatus of a GDI gasoline engine in a gasoline-gas dual fuel supply system and, more specifically, to a technology for supplying a fixed amount of gasoline to an engine when switching from a gas fuel supply state to a gasoline fuel supply state. The high-pressure fuel rail pressure control apparatus of the GDI gasoline engine in the gasoline-gas dual fuel supply system according to the present invention comprises: a gasoline injector; a high pressure pump; a high pressure fuel rail; a rail pressure sensor; a gas injector; a gasoline ECU; and a gas fuel control unit.

Description

{Pressure regulator apparatus for fuel rail of GDI Gasoline engine in Gasoline-Gas bi-fuel engine system}

In a dual fuel supply system that selectively uses gasoline and gas as engine fuels for a gasoline direct injection engine, the pressure state of a high-pressure fuel rail connected to a gasoline injector is changed to a pressure corresponding to the vehicle operation state even during gas fuel mode operation control. It relates to a technology for supplying a fixed amount of gasoline to an engine when switching from gas fuel supply state to gasoline fuel supply state by controlling the

Recently, as interest in eco-friendly vehicles is increasing, electric vehicles, hydrogen fueled vehicles, hybrid vehicles, and bi-fuel vehicles are emerging.

In particular, a bi-fuel vehicle is a method of using two fuels together in one vehicle, unlike a hybrid vehicle. It is an eco-friendly car.

In general, a fuel of a bi-fuel vehicle is used in combination with gasoline and gas in order to supplement the mutual advantages and disadvantages of gasoline and gas.

The bi-fuel vehicle is applied with a bi-fuel system for selectively using any one of gas and gasoline, and is generally configured to supplementally supply gas fuel to the gasoline vehicle.

Meanwhile, the gasoline injector has a traditional MPI structure in which fuel is injected by being located in the intake manifold, but recently, a GDI structure in which a gasoline injector directly injects fuel into a combustion chamber has been developed and applied to gasoline vehicles.

1 illustrates the structure of a gasoline injector and a gas injector having a GDI structure. That is, the gasoline injector 1 directly injects fuel into the engine 2 combustion chamber, and the gas injector 3 is positioned in the intake manifold 4 like the MPI structure to inject fuel into the engine 2 combustion chamber. do.

In a bi-fuel system equipped with a gasoline injector and a gas injector of this GDI structure, in gasoline fuel mode, the ECU supplies low-pressure gasoline fuel to the high-pressure fuel rail in the form of high pressure through the high-pressure pump, and gasoline connected to the high-pressure fuel rail. Gasoline fuel is injected into the engine through an injector. At this time, the ECU controls the injection of gasoline fuel to correspond to the current driving state by adjusting the pressure of the high-pressure fuel rail.

As such, when the gasoline fuel mode is switched from the gasoline fuel mode to the gas fuel mode, gas fuel is supplied to the engine through the gas injector thereafter, and the high-pressure fuel rail connected to the gasoline injector maintains the high-pressure state in the previous gasoline fuel mode. . At this time, the gas controller controlling the gas injector provides the pressure information of the high-pressure fuel rail corresponding to the current driving state to the ECU, and the ECU recognizes the value informed by the gas controller as the current pressure value of the high-pressure fuel rail.

However, when switching from gas fuel mode to gasoline fuel mode while the high-pressure fuel rail maintains the high-pressure state as described above, the ECU does not accurately recognize the pressure state of the high-pressure fuel rail and adjusts to the current driving state of the vehicle. A corresponding gasoline injection control signal is generated, and the gasoline injector is operated according to the gasoline injection control signal.

Accordingly, while the high-pressure fuel rail maintains the high-pressure state, more gasoline is injected into the engine than the gasoline injection amount required by the vehicle, and thus there is a problem in that the engine knocking phenomenon occurs. In particular, this knocking phenomenon damages the engine by hitting the cylinder head and the piston, and once knocking occurs, the surface of the piston and the cylinder becomes abnormally high temperature, so the knocking becomes more and more likely to occur.

In addition, when gasoline is oversupplied to the engine, there may be a problem in that driving defects such as sudden acceleration or engine shock may occur due to driving the engine with more than the output desired by the driver.

That is, a more stable engine operating method is required in a bi-fuel system using gasoline fuel and gas fuel.

1. Korea Patent No. 10-1593625 (Title of the invention: engine control device and method for bi-fuel vehicle) 2. Korea Patent No. 10-2073628 (Title of the invention: Gasoline fuel supply control device and method for natural gas and gasoline bi-fuel vehicles)

Accordingly, the present invention sets the pressure state of the high-pressure fuel rail connected to the gasoline injector to the target pressure level corresponding to the vehicle operation state even during gas fuel mode operation control in a dual fuel supply system that selectively uses gasoline and gas as fuel of a GDI gasoline engine. When the fuel mode is switched from gas to gasoline by setting as The technical purpose is to provide a control device.

According to one aspect of the present invention for achieving the above object, in a high-pressure fuel rail control device of a gasoline-gas dual fuel supply system that allows gasoline and gas to be selectively used as fuel for a vehicle engine, gasoline injection control A gasoline injector for injecting gasoline into the vehicle engine according to a signal, a high-pressure pump for outputting gasoline in a low-pressure state supplied from the gasoline supply unit in a high-pressure state, and gasoline in a high-pressure state connected to the output terminal of the high-pressure pump and outputted from the high-pressure pump A high-pressure fuel rail that supplies gas to a gasoline injector, a rail pressure sensor that measures and outputs the pressure of the high-pressure fuel rail, a gas injector that injects gas according to a gas injection control signal to supply gas to the vehicle engine, based on vehicle driving information The gasoline ECU generates a gasoline injection control signal and outputs it to the gasoline injector, and it is placed between the gasoline ECU and the high-pressure pump to connect the gasoline ECU and the high-pressure pump in the gasoline mode, and between the gasoline ECU and the high-pressure pump in the gas fuel mode. In addition to generating a gas injection control signal based on vehicle driving information and outputting it to the gas injector, There is provided a high-pressure fuel rail pressure control device for a GDI gasoline engine in a gasoline-gas dual fuel supply system, characterized in that it includes a gas fuel control unit for controlling the pressure state of the high-pressure fuel rail.

In addition, the rail pressure sensor outputs high-pressure fuel rail pressure information to the gas fuel control unit, and the gas fuel control unit provides rail pressure information received from the rail pressure sensor in gasoline mode to the gasoline ECU. A high-pressure fuel rail pressure control device for a GDI gasoline engine in a dual fuel supply system is provided.

In addition, the gas fuel control unit generates a valve control signal for regulating the open state of the solenoid valve provided in the high-pressure pump based on the rail pressure information applied from the rail pressure sensor, and provides it to the solenoid valve of the high-pressure pump. There is provided a high-pressure fuel rail pressure control device for a GDI gasoline engine in a gasoline-gas dual fuel supply system, characterized in that it is configured to decrease or increase the output pressure.

In addition, the gas fuel control unit is the output pressure of the high-pressure pump to correspond to the pressure value corresponding to the difference between the target rail pressure value corresponding to the engine speed and the engine load ratio and the current pressure value of the high-pressure fuel rail received from the rail pressure sensor. There is provided a high-pressure fuel rail pressure control device for a GDI gasoline engine in a gasoline-gas dual fuel supply system, characterized in that it generates a valve control signal for regulating the gas.

In addition, a pump switch located between the gasoline ECU and the high-pressure pump and selectively connecting a valve control signal output from the gasoline ECU to a first output terminal or a second output terminal, and a pump switch connected to the first output terminal of the pump switch and applied from the pump switch It is configured to further include a pressure damper that changes the valve control signal to be lowered and outputs the output pressure of the high-pressure pump, and the gas fuel control unit is a valve output from the gasoline ECU when the engine speed is less than a certain level in the gas fuel mode. Gasoline-gas dual fuel supply, characterized in that the control signal is output to the first output stage, and when the engine speed is above a certain level, the valve control signal output from the gasoline ECU is directly applied to the high-pressure pump through the second output stage. In the system, a high-pressure fuel rail pressure control device for a GDI gasoline engine is provided.

In addition, the gasoline ECU outputs a current value corresponding to the high-pressure pump output pressure as a valve control signal, and the pressure damper comprises a resistor that attenuates the current signal applied from the gasoline ECU to a certain level and outputs the output. A high-pressure fuel rail pressure control device for a GDI gasoline engine in a gas dual fuel supply system is provided.

According to the present invention, when the gas fuel supply state is switched from the gas fuel supply state to the gasoline fuel supply state in the dual fuel supply system that selectively uses gasoline and gas as engine fuel, the amount of gasoline currently required by the vehicle is injected into the engine, so that more It is possible to safely supply engine fuel as well as to prevent engine knocking and impact caused by excessive supply of gasoline to the engine.

1 is a view for explaining injection positions of a gasoline injector and a gas injector in a dual fuel supply system;
2 is a view showing a schematic configuration of a high-pressure fuel rail pressure control device of a GDI gasoline engine in the gasoline-gas dual fuel supply system according to the first embodiment of the present invention.
3 is a block diagram showing the functional separation of the internal configuration of the gas fuel control unit 500 shown in FIG.
4 is a block diagram showing the configuration of the control unit 540 shown in FIG. 3 separated for each fuel supply mode.
Figure 5 is a view for explaining the operation of the fuel injection device of the gasoline-gas dual fuel supply system shown in Figure 2;
6 is a view illustrating a pressure state measurement result of a high-pressure fuel rail during gas mode operation of a vehicle in a conventional dual fuel system and a dual fuel system according to the first embodiment of the present invention.
7 is a view for explaining a high-pressure fuel rail pressure control device of the GDI gasoline engine in the gasoline-gas dual fuel supply system according to the second embodiment of the present invention.
FIG. 8 is a view illustrating a measurement result of a pressure state of a high-pressure fuel rail when the vehicle operates in gas mode in the dual fuel system shown in FIG. 7;

The configuration shown in the embodiments and drawings described in the present invention is only a preferred embodiment of the present invention, and does not express all the technical ideas of the present invention, so the scope of the present invention is the embodiment and drawings described in the text should not be construed as being limited by That is, since the embodiment may have various changes and may have various forms, it should be understood that the scope of the present invention includes equivalents capable of realizing the technical idea. In addition, since the object or effect presented in the present invention does not mean that a specific embodiment should include all of them or only such effects, it should not be understood that the scope of the present invention is limited thereby.

All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Terms defined in a commonly used dictionary should be interpreted as being consistent with the meaning of the context of the related art, and cannot be interpreted as having an ideal or excessively formal meaning not explicitly defined in the present invention.

First, the present invention can be applied to a gasoline-gas dual fuel supply system in which a direct injection gasoline vehicle is equipped with a gas fuel supply device for an aftermarket vehicle to selectively use gas and gasoline as fuel for a gasoline engine in a gasoline vehicle. and can be applied to a bi-fuel vehicle that supplies dual fuel to a gasoline engine.

1 is a view showing a schematic configuration of a high-pressure fuel rail pressure control device of a GDI gasoline engine in a gasoline-gas dual fuel supply system according to a first embodiment of the present invention.

1, the high-pressure fuel rail pressure control device of the GDI gasoline engine in the gasoline-gas dual fuel supply system according to the present invention includes an engine 100, a gasoline supply unit 200, a gas supply unit 300, and a gasoline ECU. It is configured to include a 400 and a gas fuel control unit (500).

Here, the engine 100, the gasoline supply unit 200, and the gasoline ECU 400 are components that are fixedly mounted to the direct injection gasoline vehicle, and the gas supply unit 300 and the gas fuel control unit 500 are installed in the gasoline vehicle after-sales service. It may be a configuration of a gas fuel supply device for a vehicle installed for the market.

The engine 100 provides driving power to the vehicle by burning fuel supplied from the gasoline supply unit 200 and the gas supply unit 300 .

At this time, the gasoline supply unit 200 outputs from the gasoline tank 210 in which the gasoline is accommodated, the high-pressure pump 220 that receives the gasoline in the gasoline tank 210 through the low-pressure fuel line and outputs it at high pressure, and the high-pressure pump 220 . A high-pressure fuel rail 230 for distributing and outputting the high-pressure gasoline to be a plurality of gasoline injectors 240, a plurality of gasoline injectors 240 for injecting gasoline fuel supplied from the high-pressure fuel rail 230 to the engine 100, and, It is configured to include a rail rail pressure sensor 250 for detecting the internal pressure of the high-pressure fuel rail (230). At this time, the high-pressure pump 220 is provided with a solenoid valve 221 for adjusting the gasoline pressure output to the high-pressure fuel rail 230 .

The gas supply unit 300 includes a gas tank 310 in which gas fuel such as LPG, LNG, CNG, etc. is accommodated, and a gas injector 320 for injecting the gas fuel supplied from the gas tank 310 to the engine 100 . At this time, the gas supply unit 300 is provided with a solenoid valve, a pressure gauge, a vaporizer (in the case of LPG), a gas pressure control regulator (in the case of CNG or LNG), a gas filter, and the like. And, as shown in FIG. 1 , the gasoline injector 240 has a GDI structure for directly injecting gasoline into the engine 100 , and the gas injector 320 has a structure for injecting gas fuel to the intake manifold.

In FIG. 2 , the gasoline ECU 400 performs overall control processing for the gasoline vehicle, and in particular is connected to various in-vehicle devices and sensors to determine the state of the vehicle and controls the operation of the connected devices based on this. Control.

The gasoline ECU 400 generates a gasoline injection control signal for injecting gasoline to the engine 100 through the gasoline supply unit 200 based on vehicle driving information applied from in-vehicle devices and various sensors, and It is transmitted to the gasoline injector 240 side. The gasoline injector 240 injects gasoline into the engine 100 according to the gasoline injection control signal. In this case, the sensor includes a map sensor that detects the amount of air supplied to the engine and a cam position sensor that detects the engine rotation speed, and these sensors may be directly connected to the gasoline ECU 400 . In addition, the gasoline ECU 400 receives vehicle driving information through CAN communication with in-vehicle devices.

The gas fuel control unit 500 generates a gas injection control signal for injecting gas fuel and transmits it to the gas injector 320 . The gas injector 320 injects gas fuel into the engine 100 according to the gas injection control signal.

In addition, the gas fuel control unit 500 collects rail pressure information from the rail pressure sensor 250 of the gasoline supply unit 200 when gas fuel is supplied, and controls the solenoid valve 221 of the gasoline high pressure pump 222 based on this. to set the pressure environment of the high-pressure fuel rail 230 .

The gas fuel control unit 500 receives the same vehicle driving information as the ECU control unit 400 through the CAN line, generates a gas injection control signal based on the vehicle driving information, and the gasoline supply unit 200 and the gasoline ECU. The connection line between the 400 is cut off, and a normal response signal of the gasoline supply unit 200 is generated and provided to the gasoline ECU 400 .

3 is a block diagram showing the functional separation of the internal configuration of the gas fuel control unit 500 shown in FIG.

Referring to FIG. 3 , the gas fuel control unit 500 includes a fuel supply setting unit 510 , a virtual injector 520 , a data memory 530 , and a control unit 540 .

The fuel supply setting means 510 is an injector switch 511 that selectively connects one of the gasoline injector 240 or the virtual injector 5200 to the gasoline ECU 400, and the gasoline ECU 400 or the high pressure pump 200. and a pump switch 512 selectively connecting one of the control units 540 .

The virtual injector 520 is composed of an electronic circuit that outputs the same response signal as the gasoline injector 240 , that is, a dummy signal to the gasoline injection control signal applied from the gasoline ECU 400 .

The data memory 530 stores various information for controlling the dual fuel supply device, including information for generating an injection control signal in the controller 540 for each vehicle state.

The control unit 540 receives the same vehicle driving-related information as the gasoline ECU 400 through a CAN (Controller Area Network) line, and the control unit 540 receives one of the gasoline mode or the gas mode fuel based on the fuel change switch input. mode, and includes a gasoline operation module 541 and a gas operation module 542 as shown in FIG. 4 . The control unit 540 switches to the gas mode when the fuel changeover switch is input in the gasoline mode state, and switches to the gasoline mode when the fuel changeover switch is input in the gas mode state.

The gasoline operation module 541 transmits the gasoline injection control signal applied from the gasoline ECU 400 to the gasoline injector 240 as it is in the gasoline mode and transmits the response signal applied from the gasoline injector 240 to the gasoline ECU 400 ) to control the fuel supply setting means 510 to transmit as it is.

Also, the gasoline operation module 541 transmits a valve control signal for adjusting the output pressure of the high-pressure pump 220 applied from the gasoline ECU 400 to the solenoid valve 221 of the high-pressure pump 220 as it is.

That is, the gasoline operation module 541 establishes a communication path in a pure state in which the gasoline ECU 400 and the gasoline injector 240 are directly connected, and the gasoline ECU 400 and the high pressure pump 220 are directly connected to the gasoline ECU. The gasoline injector 240 and the high-pressure pump 220 are directly controlled by 400 to inject gasoline into the engine 100 to correspond to the current driving state.

In addition, the gasoline operation module 541 receives rail pressure information received from the rail pressure sensor 250 to generate a gasoline injection control signal based on the pressure of the high-pressure fuel rail 230 in the gasoline ECU 400 in the gasoline mode. It may be provided by the gasoline ECU 400 .

The gas operation module 542 is operated in the gas mode, and allows gas fuel to be injected into the engine 100 to correspond to the current driving state.

The gas operation module 542 includes a gas supply block 542A and a rail pressure control block 542B.

The gas supply block 542A calculates a gas injection section and a gas injection amount corresponding to vehicle driving information received through the CAN line in the gas mode state, and generates a gas injection control signal corresponding thereto. In this case, the gas supply block 542A may receive a sensor value from the gasoline ECU 400 through a CAN line, or may directly receive a sensor value from the corresponding sensors.

In addition, the gas supply block 542A sets the dummy injector 520 and the gasoline ECU 400 to be connected through the injector switch 511 during the gas injection section, so that the output signal of the dummy injector 520, that is, the dummy signal is the gasoline ECU. (400) to be applied. At this time, the dummy signal performs a function of allowing the gasoline ECU 400 to recognize that the gasoline injector 240 has operated normally with respect to the gasoline injection control signal generated for controlling the gasoline injector 240 . That is, even if the injection control signal of the gasoline ECU 400 is not transmitted to the gasoline injector 240 when gas fuel is supplied, the gasoline ECU 400 receives the dummy signal and performs gasoline injection in response to the generated gasoline injection control signal. recognized as being made

In addition, the gas supply block 542A generates a gas injection control signal corresponding to the gas injection section and the gas injection amount, and provides it to the gas injector 320 so that a preset amount of gas fuel in the gas injection section is supplied to the engine 100 to be sprayed on

The rail pressure control block 542B controls the output pressure of the high-pressure pump 220 by the control unit 540 by setting the high-pressure pump 220 and the control unit 540 to be connected through the pump switch 512 during the gas injection section. By doing so, the pressure of the high-pressure fuel rail 220 is controlled.

At this time, the rail pressure control block 542B sets the pressure of the high-pressure fuel rail 230 in the gas mode to correspond to the vehicle running state, and the solenoid valve of the high-pressure pump 220 ( 221) to vary the gasoline fuel pressure state output from the high-pressure pump 220 to the high-pressure fuel rail 230 .

At this time, the rail pressure control block 542B includes a rail pressure table comprising a target rail pressure value corresponding to the engine speed and the engine load, and a target rail pressure value corresponding to the engine speed and the engine load and the rail pressure sensor 250 ) by comparing the actual high-pressure fuel rail pressure value received through, and generating a valve control signal to decrease or increase the pressure of the high-pressure fuel rail 230 by the pressure corresponding to the difference. In this case, the gasoline ECU 400 may calculate the target rail pressure value and provide the target rail pressure value to the rail pressure control block 542B through the CAN line.

Table 1 shows the rail pressure table.

700.00 1400.00 1933.50 2467.00 3000.00 4000.00 5000.00 6,000.00 12.984 6.0000 6.0000 6.0000 6.0000 6.0000 7.20000 7.2000 7.2000 15.000 6.6000 6.6000 6.9260 6.9260 6.9260 9.20000 9.2000 9.2000 20.016 8.1000 8.1000 10.7660 11.9260 11.9260 14.2000 14.2000 14.2000 24.984 9.6000 9.6000 12.2660 14.9340 16.9260 19.2000 19.2000 19.2000 30.000 11.1000 11.1000 13.7660 16.4340 19.1000 24.1000 24.2000 24.2000 35.016 16.1000 16.1000 18.7660 21.4340 24.1000 25.0000 25.0000 25.0000 39.984 21.1000 21.1000 23.7660 25.0000 25.0000 25.0000 25.0000 25.0000 45.000 25.0000 25.0000 25.0000 25.0000 25.0000 25.0000 25.0000 25.0000

In Table 1, the horizontal axis is the engine speed (700.00, 1400.00, ..), the vertical axis is the engine load (12.984, 15.000, ...), and in Table 1, the high-pressure fuel input (230) corresponding to the engine speed and engine load. ) is exemplified. Table 1 shows examples up to 6,000 rpm and 45% of engine load.

Here, the calculation of the target rail pressure value as shown in Table 1 may be calculated according to a preset algorithm based on vehicle driving information without necessarily having a rail pressure table.

Next, an operation of the high-pressure fuel rail pressure control device of the above-described gasoline-gas dual fuel supply system will be described with reference to FIG. 5 . Hereinafter, the operation of the gas fuel control unit 500 will be described as a reference.

Basically, in the present invention, the gasoline ECU 400 and the gas fuel control unit 500 are connected by a CAN line, and the gas fuel control unit 500 provides information (eg, target rail pressure value) of the gasoline ECU 400 and in-vehicle information. Information applied to devices and sensors is received through a CAN line.

In the above state, it operates in two modes, a gasoline mode and a gas mode, according to the changeover selection switch signal selected by the driver (ST100).

In gasoline mode,

The gas fuel control unit 500 transmits the gasoline injection control signal received from the gasoline ECU 400 as it is to the gasoline injector 240 , and the response signal received from the gasoline injector 240 is transmitted to the gasoline ECU 400 . A transmission/reception path between the ECU 400 and the gasoline injector 240 is set (ST210).

In addition, the gas fuel control unit 500 sets a route so that the high-pressure pump 220 is connected to the gasoline ECU 400 (ST220).

That is, the gas fuel control unit 500 connects the gasoline injector 240 with the gasoline ECU 400 through the injector switch 511 and also connects the gasoline ECU 400 with the high-pressure pump 220 , so that the gasoline ECU 400 to operate in a pure state for supplying gasoline fuel in a gasoline vehicle.

At this time, the gas fuel control unit 500 bypasses the rail pressure information received from the rail pressure sensor 250 to the gasoline ECU 400 and the gasoline ECU 400 takes this into account to generate a gasoline injection control signal. have.

In gas mode,

The gas fuel control unit 500 sets a path so that the transmission gasoline ECU 400 and the virtual injector 520 are connected through the injector switch 511 (ST310). That is, in the gas mode, the dummy signal is provided to the gasoline ECU 600 in response to the gasoline injection control signal.

In addition, the gas fuel control unit 500 generates a gas injection control signal based on vehicle driving information including the amount of air and the engine rotation speed, and provides the gas injection control signal to the gas injector 320 to control the gas injector 320 . Through the gas is supplied to the engine 100 (ST320).

In addition, the gas fuel control unit 500 blocks the path between the gasoline ECU 400 and the high pressure pump 220 through the pump switch 512 and sets the path so that the high pressure pump 220 is controlled through the control unit 540 . (ST330). That is, in the gas mode, the solenoid valve 221 of the high-pressure pump 220 is in a state controlled by the gas fuel control unit 500 .

Then, the gas fuel control unit 500 generates a valve control signal based on the target rail pressure value, and transmits the valve control signal to the solenoid valve 221 so that the output pressure of the high-pressure pump 220 corresponds to the driving state of the vehicle. Adjust (ST340). In this case, the target rail pressure value may be provided from the gasoline ECU 400 through the CAN line or may be directly determined by the gas fuel controller 500 based on vehicle driving information including the engine speed and the engine load.

Accordingly, the pressure state of the high-pressure fuel rail 230 connected to the output terminal of the high-pressure pump 220 in the gas mode state is set to correspond to the driving state.

For example, in step ST340, the gas fuel control unit 500 sets the current pressure of the high-pressure fuel rail 230 applied from the rail pressure sensor 250 to 80 bar, and the target pressure of the high-pressure fuel rail 230 corresponding to the current running state. When this is 60Bar, the gas fuel control unit 500 generates a valve control signal for opening the solenoid valve 221 of the high-pressure pump 200 to reduce the high-pressure fuel rail pressure by 20Bar, and it transmitted to the solenoid valve 221 .

6 is a diagram illustrating a pressure state of the high-pressure fuel rail 230 when the vehicle operates in gas mode, and is based on data acquired through actual driving.

6 (A) is a diagram illustrating a high-pressure fuel rail pressure state during actual driving in the case of not controlling the high-pressure fuel rail pressure during gas mode operation, where “t” is the actual high pressure obtained through the rail pressure sensor 250 . is the fuel rail pressure, and "s" is the high-pressure fuel rail target pressure according to the driving state.

According to FIG. 6 (A), the target rail pressure value (s) required according to the vehicle driving state is changed to a value between 60 and 250 Bar as time elapses, whereas the actual high-pressure fuel rail pressure value (t) is 250 It can be seen that the bar state is kept constant. In particular, when the gas mode is switched from the gas mode to the gasoline mode, the gasoline ECU ( 400) recognizes the pressure of the current high-pressure rail pressure 230 as the target rail pressure value and generates a gasoline injection control signal based on this. 100), there is a problem that gasoline is oversupplied.

Meanwhile, FIG. 6(B) is a diagram illustrating a high-pressure fuel rail pressure state during actual driving in the case of controlling the high-pressure fuel rail pressure during gas mode operation in the first embodiment of the present invention, and is a target required according to the vehicle driving state. It can be seen that the rail pressure value (s) and the actual high-pressure fuel rail pressure value (t) are set to be the same after a certain time point (eg, 25 seconds after gas mode conversion) has elapsed. 6(B), after 25 seconds of driving, the target rail pressure value (s) and the actual high-pressure fuel rail pressure value (t) are the same, and the high-pressure fuel rail pressure value (t) and the target rail pressure value (s) are It is shown as a superimposed graph.

Therefore, according to the present invention, even if the gasoline mode is switched at any point in time, the gasoline ECU 400 generates a gasoline injection control signal based on the actual target rail pressure value (s) that is the same as the actual high-pressure fuel rail pressure value (t). Therefore, it can be seen that the problem of oversupplying gasoline to the engine 100 by the pressure environment of the high-pressure fuel rail 230 can be solved.

7 is a view for explaining the high-pressure fuel rail pressure control device of the gasoline-gas dual fuel supply system according to the second embodiment of the present invention, and the internal configuration of the gas fuel control unit 700 is shown.

The high-pressure fuel rail pressure control device of the gasoline-gas dual fuel supply system according to the second embodiment of the present invention adjusts the pressure of the high-pressure fuel rail 230 based on vehicle driving information in the gas mode, but It is configured to reduce the pressure of the high-pressure fuel rail 230 by a certain level when the rail pressure control condition is satisfied.

The high-pressure fuel rail pressure control device of the gasoline-gas dual fuel supply system is configured differently only the gas fuel control unit 500 from the high-pressure fuel rail pressure control device of the gasoline-gas dual fuel supply system of the first embodiment shown in FIG. .

Referring to FIG. 7 , in the present embodiment, the gas fuel control unit 700 is a pump switch that selectively connects one of the paths that directly connect the gasoline ECU 400 to the high-pressure pump 220 or pass through the pressure damper 720 . 710 .

That is, the pump switch 710 is located between the gasoline ECU 400 and the high-pressure pump 220 , and the gasoline ECU 400 is connected to the first output terminal under the control of the control unit 730 to output the gasoline ECU 400 . As it is, it is bypassed to the high-pressure pump 220 , or the gasoline ECU 400 is connected to the second output terminal so that the output of the gasoline ECU 400 is attenuated through the pressure damper 720 and transmitted to the high-pressure pump 220 . do.

The pressure damper 720 is connected to the first output terminal of the pump switch 710 and outputs the valve control signal applied from the pump switch by changing the output pressure of the high-pressure pump 220 to be lowered. Here, the gasoline ECU 400 outputs a current signal corresponding to the valve opening degree as a valve control signal to control the solenoid valve 221 of the high-pressure pump 220, and reduces the current level of the valve control signal to a certain level. In order to do this, a resistor having a value above a certain level, for example, 47Ω, may be implemented as the pressure damper 720 .

The control unit 730 generates a gas injection signal based on vehicle driving information in the gas mode and transmits it to the gas injector 320, thereby controlling the gas fuel corresponding to the vehicle driving state to be supplied to the engine 100, When the vehicle driving information is monitored and the preset high-pressure rail pressure control condition is satisfied, the valve control signal output from the gasoline ECU 400 is attenuated by controlling the pump switch 720 through the pressure damper 720 to thereby reduce the high-pressure pump 220 . ) to be transmitted.

At this time, the control unit 730 controls the high pressure rail pressure to be reduced when the engine load factor is equal to or greater than a certain level, for example, 80% or greater.

8 is a diagram illustrating a pressure state of the high-pressure fuel rail 230 during gas mode operation in the configuration of FIG. 7 , and is based on data acquired through actual driving.

Referring to FIG. 8 , the high-pressure fuel rail is operated at 60 to 250 Bar by reducing the pressure of the high-pressure fuel rail 230 by a certain level whenever the high-pressure rail pressure control condition is satisfied while operating in the gas mode. It can be seen that the actual pressure of the high-pressure fuel rail 230 does not exceed 210 Bar.

That is, compared with FIG. 6(A), in the second embodiment (refer to FIG. 8) of the present invention, the difference between the actual high-pressure fuel rail pressure and the target rail pressure value is less than a certain level, and the engine knocking phenomenon occurs compared to the prior art. It is possible to further reduce

On the other hand, in the above embodiment, only when the vehicle operation mode is changed from the gas mode to the gasoline mode, but the present applicant applied for on January 15, 2021 Patent Application No. 10-2021-0005878 (name: gasoline- When a preset condition is satisfied in the gas mode operation section disclosed in the fuel injection device of the LPG dual fuel supply system), it can be applied to a system for supplying fuel by mixing with gasoline fuel.

100: engine, 200: gasoline supply,
210: gasoline tank, 220: high pressure pump,
221: fuel pressure control valve, 230: high-pressure fuel rail,
240: gasoline injector, 250: rail pressure sensor,
300: gas supply unit, 310: gas tank,
320: gas injector, 400: gasoline ECU,
500: gas fuel control unit.

Claims (6)

A high-pressure fuel rail control device for a gasoline-gas dual fuel supply system that allows gasoline and gas to be selectively used as fuel for a vehicle engine, comprising:
A gasoline injector for injecting gasoline to the vehicle engine according to a gasoline injection control signal;
A high-pressure pump that outputs gasoline in a low-pressure state supplied from the gasoline supply unit in a high-pressure state, and
A high-pressure fuel rail that is connected to the output terminal of the high-pressure pump and supplies high-pressure gasoline output from the high-pressure pump to the gasoline injector;
A rail pressure sensor that measures and outputs the pressure of the high-pressure fuel rail;
a gas injector for supplying gas to the vehicle engine by injecting gas according to a gas injection control signal;
A gasoline ECU that generates a gasoline injection control signal based on vehicle driving information and outputs it to a gasoline injector;
It is placed between the gasoline ECU and the high-pressure pump and connects the gasoline ECU and the high-pressure pump in gasoline mode, and blocks the gasoline ECU and the high-pressure pump in gas fuel mode, and generates a gas injection control signal based on vehicle driving information and a gas fuel controller for controlling the pressure state of the high-pressure fuel rail by controlling the output pressure of the high-pressure pump so as to correspond to vehicle driving information including the target rail pressure value, air amount, and engine speed while outputting to the gas injector Gasoline-gas dual fuel supply system, characterized in that the high-pressure fuel rail pressure control device of the GDI gasoline engine.
According to claim 1,
The rail pressure sensor outputs high-pressure fuel rail pressure information to the gas fuel control unit,
The gas fuel control unit provides the rail pressure information received from the rail pressure sensor in the gasoline mode to the gasoline ECU, the high-pressure fuel rail pressure control device of the GDI gasoline engine in the gasoline-gas dual fuel supply system.
According to claim 1,
The gas fuel control unit generates a valve control signal for adjusting the open state of the solenoid valve provided in the high-pressure pump based on the rail pressure information applied from the rail pressure sensor, and provides it to the solenoid valve to provide the output pressure of the high-pressure pump A high-pressure fuel rail pressure control device for a GDI gasoline engine in a gasoline-gas dual fuel supply system, characterized in that it is configured to decrease or increase the
4. The method of claim 3,
The gas fuel control unit adjusts the output pressure of the high-pressure pump to correspond to a pressure value corresponding to a difference between a target rail pressure value corresponding to the engine speed and the engine load ratio and a current pressure value of the high-pressure fuel rail received from the rail pressure sensor. A high-pressure fuel rail pressure control device for a GDI gasoline engine in a gasoline-gas dual fuel supply system, characterized in that it generates a valve control signal for
According to claim 1,
a pump switch positioned between the gasoline ECU and the high-pressure pump and selectively connecting a valve control signal output from the gasoline ECU to a first output terminal or a second output terminal;
It is connected to the first output terminal of the pump switch and configured to further include a pressure damper for outputting a valve control signal applied from the pump switch to lower the output pressure of the high-pressure pump,
The gas fuel control unit outputs a valve control signal output from the gasoline ECU to the first output terminal when the engine speed is less than a certain level in the gas fuel mode, and when the engine speed is higher than a certain level, the valve control signal output from the gasoline ECU is A high-pressure fuel rail pressure control device for a GDI gasoline engine in a gasoline-gas dual fuel supply system, characterized in that the control is applied to the high-pressure pump as it is through the second output stage.
6. The method of claim 5,
The gasoline ECU outputs a current value corresponding to the high-pressure pump output pressure as a valve control signal,
The pressure damper is a high-pressure fuel rail pressure control device for a GDI gasoline engine in a gasoline-gas dual fuel supply system, characterized in that it comprises a resistor that attenuates and outputs a current signal applied from the gasoline ECU to a certain level.

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