KR101061784B1 - Fuel supply control device and control method for gasoline and LP combined vehicle - Google Patents

Abstract

The present invention relates to a fuel supply control apparatus and a control method for a gasoline and LPG combined vehicle that controls the air-fuel ratio of the engine in accordance with the amount of oxygen detected from the oxygen sensor during the air-fuel ratio control using the proportional integral control, An oxygen sensor for detecting the amount of oxygen contained in the exhaust gas, an inspection means for inspecting whether the air-fuel ratio supplied to the engine is rich or lean based on an output signal from the oxygen sensor, and the air-fuel ratio based on an inspection result of the inspection means Control means for forcibly or sparingly controlling the air-fuel ratio by forcibly allocating a delay time in a state in which a proportional integral control gain value is set to a balanced value, a throttle position sensor for detecting an opening amount of a throttle valve, and the engine revolutions per minute And a rotational speed measurement unit for detecting a number, wherein the control unit comprises the throttle The entire area is divided based on the output signal of the position sensor and the RPM measurement unit, and the delay time is preset for each divided area, and when the air-fuel ratio is controlled richly, the first delay time of the rich state section is determined. A configuration for increasing and decreasing the second delay time of the lean state section is provided.

By using the fuel supply control device as described above, when the air-fuel ratio is controlled to be rich or lean, the air-fuel ratio is controlled to be rich or lean by increasing or decreasing the delay time while uniformly setting the gain value of the proportional integral control. Shock and jerk of the vehicle can be prevented from occurring.

Gasoline, LP, Fuel Supply Control, Oxygen Sensor, Proportional Integral Control

Description

FUEL SUPPLY CONTROL DEVICE AND CONTROL METHOD FOR PETROL AND LPG VEHICLE {APPRATUS AND METHOD FOR CONTROLLING

The present invention relates to a fuel supply control device and a control method for a gasoline and LPG combined vehicle, and more particularly, to control the air-fuel ratio of the engine in accordance with the amount of oxygen detected from the oxygen sensor when controlling the air-fuel ratio using a proportional integral bear The present invention relates to a vehicle fuel supply control device and a control method.

Conventional gasoline and liquefied petroleum gas (Liquefied Gas) combined vehicle is carried out by the gasoline fuel at start-up, predetermined conditions after starting the gasoline, for example, a certain time after starting the engine, When the coolant temperature is above a certain temperature, the fuel is automatically switched from gasoline to Elp.

The technology of the fuel supply control device and the control method of the combined gasoline and LPG vehicle is well shown in the Korean Patent Application No. 2008-0071454 filed by the present applicant.

1A and 1B are graphs illustrating a duty calculation method according to a control method of a fuel supply control apparatus of a conventional gasoline and LPG combined vehicle.

That is, in the conventional fuel supply control method, pulse width modulation (PWM) is performed by performing proportional integral control of an oxygen sensor output value in a section where the opening amount of the throttle valve is low and a middle section. Calculate the duty of the control signal.

First, a case in which gain values are balanced will be described with reference to FIG. 1A.

As shown in FIG. 1A, when the gain value of the air-fuel ratio is balanced, if the current oxygen sensor state is rich and the previous oxygen sensor state is lean, the PWM output duty value is the current PWM output duty value −. It becomes a 1st proportional control gain value P1.

On the other hand, if the current oxygen sensor state is rich and the previous oxygen sensor state is rich, the PWM output duty value becomes the current PWM output duty value-first integral control gain value I1.

On the other hand, if the current oxygen sensor state is lean and the previous oxygen sensor state is rich, the PWM output duty value becomes the current PWM output duty value + second proportional control gain value P2, and the current oxygen sensor state is lean, If the oxygen sensor is also sparse, the PWM output duty value becomes the current PWM output duty value + second integral control gain value I2.

Here, the first and second proportional control gain values P1 and P2 are referred to as x (%), and the first and second integral control gain values I1 and I2 are defined as y (% / s).

On the other hand, in the case where the throttle opening amount is high, the duty table according to the engine RPM is called and used, and the PWM output (x) is used.

In addition, in the acceleration section, the PWM output is x (%), and the deceleration section is when the current engine RPM is greater than the fuel cut reference RPM, and while the above condition is maintained, the PWM output is the x (%) as in the acceleration section. ) Value.

However, in order to make the air-fuel ratio rich or sparse in the proportional integral control, each gain value of the proportional integral control must be unbalanced.

For example, as shown in FIG. 1B, in order to richly control the air-fuel ratio, the third and fourth proportional control gain values P3 and P4 and the third and fourth integral control gain values I3 and I4 are unbalanced, respectively. To allocate. In this way, when each gain value is unbalanced, the increase / decrease of fuel is largely biased to one side, and shock and jerk occur in the vehicle.

Accordingly, the conventional fuel supply control method for a combined gasoline and LPG vehicle unbalancedly allocates the gain value of the proportional integral control during proportional integral control so that the air-fuel ratio is rich or lean, due to shock and jerk generated in the vehicle. There was a problem that a sufficient operating performance of the vehicle cannot be obtained.

The present invention is to solve the above problems, an object of the present invention is to provide a fuel supply control device and a control method for a gasoline and LPG combined vehicle to prevent the generation of shock and jerk of the vehicle during the air-fuel ratio control.

According to a feature of the present invention for achieving the above object, the present invention is a combined gasoline and LPG vehicle, the oxygen sensor for detecting the amount of oxygen contained in the exhaust gas, the engine based on the output signal from the oxygen sensor The air-fuel ratio is determined by forcibly allocating a delay time in a state in which a proportional integral control gain value of the air-fuel ratio is set in a balanced manner based on the inspection means for inspecting whether the air-fuel ratio supplied to the rich or lean state and the test means are inspected. It includes a control means for controlling the rich or sparse.

The present invention further includes a throttle position sensor for detecting an opening amount of a throttle valve and a rpm measurement unit for detecting the RPM of the engine, and the controller is based on an output signal of the throttle position sensor and the RPM measurement unit. And classifying the entire area, and setting the delay time in advance for each divided area.

The controller may be configured to reduce the first delay time of the lean state section and increase the second delay time of the rich state section when the air-fuel ratio is richly controlled.

According to another feature of the present invention, the present invention provides a fuel supply control method for a gasoline and LPG combined vehicle, detecting the amount of oxygen contained in the exhaust gas using an oxygen sensor, the engine based on the output signal of the oxygen sensor Inspecting whether the air-fuel ratio supplied to the rich or lean state is determined, forcibly allocating a delay time based on a test result of the inspection step, a current state and a previous state of the air-fuel ratio, and when the allocated delay time elapses. And performing proportional integral control of the air-fuel ratio.

In the allocating step, if the current air-fuel ratio is rich and the previous air-fuel ratio is lean, performing a first proportional control after forcibly delaying the first delay time and the current air-fuel ratio is rich and the previous air-fuel ratio is rich. If it is, characterized in that it comprises the step of immediately performing the first integral control.

In the allocating step, if the current air-fuel ratio is lean and the previous air-fuel ratio is rich, performing a second proportional control after forcibly delaying the second delay time and the current air-fuel ratio is lean and the previous air-fuel ratio is lean. And if so, immediately performing a second integral control.

The first and second proportional control and the first and second integral control are performed by gain values which are set in a balanced manner.

In the allocating step, when the air-fuel ratio is controlled in a rich state, the first delay time allocated to the lean state section of the air-fuel ratio is decreased or the second delay time allocated to the rich-state section of the air-fuel ratio is increased, and the air-fuel ratio is increased. When controlling to a lean state, characterized in that to increase the first delay time or to reduce the second delay time.

In the allocating step, when the air-fuel ratio is controlled in the rich state, the first delay time allocated to the lean state section of the air-fuel ratio is decreased, and the second delay time allocated to the rich state section of the air-fuel ratio is increased, and the air-fuel ratio is increased. When controlling in a lean state, the first delay time is increased and the second delay time is reduced.

The delay time is characterized in that the whole area is divided based on the opening amount of the throttle valve and the engine revolutions per minute, and is set in advance for each of the divided areas.

As described above, the present invention controls to maintain a rich or lean state by forcibly allocating a delay time for a predetermined time during proportional integral control. Accordingly, in the present invention, when the air-fuel ratio is controlled rich or lean, the air-fuel ratio is enriched by increasing or decreasing the delay time of the rich state section and / or the lean state section without allocating the gain value of the proportional integral control to one side. Or lean control. As a result, the present invention has the effect of preventing the shock and jerk generated in the vehicle during proportional integral control to improve the operation performance of the vehicle.

Hereinafter, a fuel supply control apparatus and a control method for a combined gasoline and LPG vehicle according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram illustrating a configuration of a fuel supply control apparatus for a combined gasoline and LPG vehicle according to a preferred embodiment of the present invention.

As shown in FIG. 2, the fuel supply control apparatus for a combined gasoline and LPG vehicle according to an exemplary embodiment of the present invention includes a switch module 11, a sensing unit 12, an LPI fuel system 16, and a gasoline fuel gauge ( 17) and a control unit 21.

The switch module 11 receives any one of the LLP fuel gauge 16 and the gasoline fuel gauge 18 from the user and transmits a corresponding signal to the controller 21.

The detection means 12 is an oxygen sensor 13 for detecting the amount of oxygen contained in the exhaust gas, the throttle position sensor 14 for detecting the opening amount of the throttle valve (not shown) and the engine revolutions per minute (Revolution Per And a RPM measuring unit 15 for measuring Minute, hereinafter, referred to as 'RPM'. The sensing means 12 transmits the output signals of the oxygen sensor 13, the throttle position sensor 14, and the RPM measuring unit 15 to the controller 21.

The LLP fuel system 16 and the gasoline fuel system 18 selectively supply LLP fuel or gasoline fuel to the engine under the control of the controller 21 based on the signal selected by the switch module 11.

The LLP fuel system 16 includes a solenoid valve 17 for blocking the supply of LLP fuel. The gasoline fuel system 18 includes a gasoline pump 19 for supplying the gasoline fuel, and an injector 20 for injecting gasoline fuel supplied from the gasoline pump 19 into the cylinder of the engine. .

The controller 21 selectively controls the fuel supplied to the engine. That is, the controller 21 outputs a PWM control signal to the LLP fuel system 16 to control the air-fuel ratio supplied into the cylinder of the engine in the state selected to supply the LLP fuel through the switch module 11. For example, the controller 21 checks whether the air-fuel ratio is rich or lean using the amount of oxygen in the exhaust gas detected by the oxygen sensor 13. As a result of the inspection, if the current air-fuel ratio is rich and the previously detected air-fuel ratio is lean, the controller 21 forcibly delays the preset first delay time and then performs the proportional control by the first proportional control gain. The duty of the PWM control signal is calculated. On the other hand, if the previous air-fuel ratio was rich, the duty of the PWM control signal is calculated to perform integral control immediately by the first integral control gain value. In addition, if the current air-fuel ratio is lean state and the previous air-fuel ratio is rich, the controller 21 forcibly delays the preset second delay time, and then performs proportional control by the second proportional control gain value, and the previous air-fuel ratio is If it is lean, the duty of the PWM control signal is calculated to perform integral control by the second integral control gain value.

Next, the first and second delay times forcibly delaying the proportional integral control operation of the controller will be described with reference to FIG. 3.

3 is a graph of setting values for each area divided according to signals output from the throttle position sensor and the RPM measurement unit.

As shown in FIG. 3, the control unit 21 outputs the voltage V of the opening amount of the throttle valve from the throttle position sensor 14 and the RPM of the engine measured from the RPM measuring unit 15. Areas are divided based on the predetermined values, and the set values used as the first and second delay times are set for each air-fuel ratio.

For example, the set value may be set to increase as the output voltage of the throttle position sensor 14 is higher and RPM is higher.

That is, since the controller 21 delays the duty of the PWM control signal while maintaining the current calculated value, the first delay time is set to the time when the lean air-fuel ratio is supplied to the combustion chamber in the lean state section. The second delay time is set to a time at which the rich air-fuel ratio is supplied to the combustion chamber in the rich state section.

Therefore, the air-fuel ratio becomes thin when the first delay time increases and / or the second delay time decreases. On the other hand, when the first delay time decreases and / or the second delay time increases, the air-fuel ratio becomes rich.

Hereinafter, a method of controlling fuel supply of a gasoline and LPG combined vehicle according to a preferred embodiment of the present invention will be described in detail with reference to FIGS. 4, 5A, and 5B.

4 is a flowchart illustrating a fuel supply control method for a gasoline and LPG combined vehicle according to a preferred embodiment of the present invention, and FIGS. 5A and 5B are graphs illustrating a duty calculation method according to the fuel supply control method of FIG. 4. Is shown.

In the present embodiment, a duty calculation method for air-fuel ratio control in the Elpji mode using the Elpji fuel will be described. However, it should be noted that the present invention can perform the air-fuel ratio control using the same method not only in the LPG mode but also in the gasoline mode.

First, a case where the air-fuel ratio is controlled in a balanced manner will be described with reference to FIGS. 4 and 5A.

Referring to FIG. 4, the control unit 21 opens the solenoid valve 17 to supply the LLP fuel to the combustion chamber of the engine in the LLP mode, and starts the air-fuel ratio control in the LLP mode (S10). At this time, the oxygen sensor 13 detects the amount of oxygen in the exhaust gas, the detection means 12 transmits an output signal having a voltage value corresponding to the detected amount of oxygen to the control unit 21, the control unit 21 is detected The air-fuel ratio is checked according to the amount of oxygen (S11). Thereafter, the controller 21 checks whether the current air-fuel ratio is a rich state higher than a preset reference value (S12).

As a result of the inspection in step S12, when the current air-fuel ratio is in a rich state, the controller 21 checks whether the previous air-fuel ratio is in a lean state lower than the reference value (S13).

If the previous air-fuel ratio was lean in the step S13, as shown in FIG. 5A, the controller 21 forcibly delays the next control operation during the first preset delay time D1 (S14). As shown in FIG. 3, the first delay time D1 is divided according to the output voltage V of the throttle position sensor 14 and the RPM of the engine, and is preset in each region.

Subsequently, when the first delay time D1 elapses in step S14, the controller 21 performs proportional control by a predetermined first proportional control gain value P11, for example, 2% (S15). .

On the other hand, if the previous air-fuel ratio was rich in the step S13, the control unit 21 immediately performs the integral control by the first integral control gain value I11, for example, 4% / s (S16).

On the other hand, when the inspection result of the step (S12), when the current air-fuel ratio is in a lean state (S17), the control unit 21 checks whether the previous air-fuel ratio was a rich state higher than the reference value (S18).

Thus, if the previous air-fuel ratio was rich in step S18, the control unit 21 forcibly delays the next control operation during the second preset delay time D2 (S19). The second delay time D2 is a time set in advance by the method as shown in FIG. 3, similarly to the first delay time D1.

When the air-fuel ratio is controlled in a balanced manner, the first and second delay times D1 and D2 may be set to the same value, for example, 75 ms.

Subsequently, when the second delay time D2 elapses in the step S19, the controller 21 performs proportional control by a preset second proportional control gain value P12, for example, 2% (S19).

On the other hand, if the previous air-fuel ratio was lean in step S18, the control unit 21 immediately performs the integral control by the second integral control gain value I12, for example, 4% / s (S21).

Such steps S12 to S21 are continuously repeated until the ignition key, which is not shown, is turned off.

Next, a case where the air-fuel ratio is disproportionately controlled to control the rich state will be described with reference to FIG. 5B.

When the accelerator is operated to accelerate the vehicle, the control unit 21 controls to enrich the air-fuel ratio.

That is, the control unit 21 changes and allocates only the delay times D1 and D2 in a state where the gain value is uniformly set. Referring to FIG. 5B, the control unit 21 uniforms the first and second proportional control gain values P11 and P12 and the first and second integrating control gain values I11 and I12 in the same manner as in FIG. 5A. Values, such as 2% and 4% / s, and increase and decrease the first and second delay times D1 and D2 and assign them to the third and fourth delay times D3 and D4, such as 50 ms and 100 ms. do. In FIG. 3, the opening amount of the throttle valve increases to form a rich air-fuel ratio state, thereby increasing the output voltage V of the throttle position sensor 14 and the RPM of the engine. Accordingly, the third delay time D3 allocated to the lean state section of the air-fuel ratio is lower than the first delay time D1, and the fourth delay time D4 assigned to the rich state section of the air-fuel ratio is the second delay time. It is increased than (D2). As a result, the present invention reduces the third delay time D3 of the lean state section while uniformly setting the air-fuel ratio gain value of proportional integral control to either side, and reduces the fourth of the rich state section. By increasing and assigning the delay time D4, the air-fuel ratio can be controlled richly.

On the other hand, in the case of forming a lean air-fuel ratio state, although not shown, the controller 21 sets the third delay time D3 of the lean state section to the first delay time in a state where the air-fuel ratio gain value of the proportional integral control is uniformly set. It is also possible to control the fuel efficiency lean by increasing it from D1) and reducing the fourth delay time D4 of the rich state section to the second delay time D2 and assigning it to 100 Hz and 50 Hz, respectively.

 Through the above-described process, the present invention controls the air-fuel ratio to a rich or lean state by selectively increasing and decreasing the delay time while uniformly setting the air-fuel ratio gain value of the proportional integral control. Accordingly, the present invention prevents the occurrence of shock and jerk of the engine generated during air-fuel ratio control.

The scope of the present invention is not limited to the embodiments described above, but is defined by the claims, and various changes and modifications can be made by those skilled in the art within the scope of the claims. It is self evident.

In the above embodiment, in order to control the air-fuel ratio richly or sparse, the first and second delay times D1 and D2 are simultaneously changed and set as the third and fourth delay times D3 and D4. It is not necessarily limited.

That is, in the present invention, when the air-fuel ratio is richly controlled, only the fourth delay time D4 of the rich state section is increased from the second delay time D2, or only the third delay time D3 of the lean state section is removed. It can be changed to decrease more than one delay time D1.

In addition, when the air-fuel ratio is leanly controlled, the third delay time D3 may be increased to increase the first delay time D1 only or the fourth delay time D4 may be changed to increase the second delay time D2. have.

1A and 1B are graphs illustrating a duty calculation method by a control method of a fuel supply control apparatus for a conventional gasoline and LPG combined vehicle.

Figure 2 is a block diagram showing the configuration of a fuel supply control apparatus for a gasoline and LPG combined vehicle according to a preferred embodiment of the present invention.

Figure 3 is a graph of the setting value for each area divided according to the signal output from the throttle position sensor and the RPM measurement unit.

4 is a flow chart illustrating a fuel supply control method for a combined gasoline and LPG vehicle according to a preferred embodiment of the present invention.

5A and 5B are graphs illustrating a duty calculation method according to the fuel supply control method of FIG. 4.

`` Explanation of symbols for main parts of drawings ''

11: switch module 12: sensing means

13: oxygen sensor 14: throttle position sensor

15: RPM measurement unit 16: LLP fuel gauge

17: solenoid valve 18: gasoline fuel gauge

19: gasoline pump 20: injector

21: control unit

Claims (10)

In a gasoline and elpgi combined vehicle, Oxygen sensor to detect the amount of oxygen contained in the exhaust gas, Inspection means for inspecting whether the air-fuel ratio supplied to the engine is rich or lean based on the output signal from the oxygen sensor; And a control unit configured to control the air-fuel ratio richly or sparse by forcibly allocating a delay time in a state where the proportional integral control gain value of the air-fuel ratio is set in a balanced manner based on the test result of the inspection means. Feed control. The method of claim 1, Throttle position sensor for detecting the opening amount of the throttle valve Further comprising a rpm measurement unit for detecting the rpm of the engine, And the control unit divides the entire area based on the output signal of the throttle position sensor and the RPM measurement unit, and presets the delay time for each divided area. The method of claim 2, wherein the control unit When the air-fuel ratio is richly controlled, the fuel supply control device, characterized in that to reduce the first delay time of the lean state section, and to increase the second delay time of the rich state section. In the fuel supply control method of the gasoline and LPG combined vehicles, Detecting the amount of oxygen contained in the exhaust gas using an oxygen sensor, Checking whether the air-fuel ratio supplied to the engine is rich or lean based on the output signal of the oxygen sensor; An allocating step of forcibly allocating a delay time on the basis of the test result of the test step, the current state and the previous state of the air-fuel ratio; And performing a proportional integral control of the air-fuel ratio when the allocated delay time has elapsed. The method of claim 4, wherein the assigning step If the current air-fuel ratio is rich and the previous air-fuel ratio is lean, performing a first proportional control after forcibly delaying the first delay time; And if the current air-fuel ratio is rich and the previous air-fuel ratio is rich, immediately performing first integral control. The method of claim 5, wherein the assigning step If the current air-fuel ratio is lean and the previous air-fuel ratio was rich, performing a second proportional control after forcibly delaying the second delay time; And if the current air-fuel ratio is lean and the previous air-fuel ratio was lean, immediately performing a second integral control. The method of claim 6, And the first and second proportional control and the first and second integral control are performed by gain values which are set in a balanced manner. 8. The method of claim 7, wherein the assigning step When the air-fuel ratio is controlled in the rich state, the first delay time allocated to the lean state section of the air-fuel ratio is decreased or the second delay time allocated to the rich state section of the air-fuel ratio is increased, And controlling the air-fuel ratio in a lean state, increasing the first delay time or reducing the second delay time. 8. The method of claim 7, wherein the assigning step When the air-fuel ratio is controlled in a rich state, the first delay time allocated to the lean state section of the air-fuel ratio is decreased, and the second delay time allocated to the rich state section of the air-fuel ratio is increased, And controlling the air-fuel ratio in a lean state, increasing the first delay time and reducing the second delay time. 10. The method of claim 4, wherein the delay time is A fuel supply control method according to claim 1, wherein the entire area is divided based on the opening amount of the throttle valve and the engine revolutions per minute, and is preset for each divided area.

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