KR20100044530A - System for control a starting fuel of engine and method thereof - Google Patents

Abstract

PURPOSE: A device and a method for controlling the amount of fuel for starting an engine are provided to improve starting performance and accurately calculate the amount of the fuel supplied to the engine by directly measuring the volatility of the fuel through an oxygen sensor. CONSTITUTION: If an engine starting preparation condition is detected, a fuel volatility determining condition is determined by the engine cooling state. After a purge control solenoid valve is opened, an air fuel ratio variation is measured through an oxygen sensor(S109). The measured value of the air-fuel ratio variation is applied to the controlling amount of fuel factor map consisting of the coefficient of correlation of the fuel evaporation pressure and then the correction value is extracted. The extracted correction value is applied according to the air-fuel ratio variation amount to the starting fuel amount(S113).

Description

TECHNICAL FOR CONTROL A STARTING FUEL OF ENGINE AND METHOD THEREOF

The present invention relates to a starting fuel amount control apparatus and method for accurately calculating and controlling the amount of fuel supplied at start-up by detecting the evaporation pressure of fuel generated in the fuel tank immediately before starting the engine from a change in air-fuel ratio.

The characteristics of fuels in different countries and regions around the world are different from each other, and there are also large differences in volatile characteristic values that affect combustibility.

In particular, since fuel evaporation (volatility) has a large influence on starting, fuel evaporation (volatility) is large and small, and thus has much influence on initial starting performance and combustion of fuel. Control is also directly related to engine performance and quality.

The amount of fuel injected at engine start-up is very closely related to emission and initial start-up, which governs engine performance and quality.

Patent application 2005-0094826 describes a technique for determining a low quality fuel in a vehicle, and patent application 2003-0092649 describes a technique for determining and correcting a low vaporization fuel in a vehicle.

The former technique sets a reference value for each coolant temperature factor value and engine speed according to the coolant temperature detected after the vehicle starts, and determines whether an increase in the engine speed reaches a reference value, and sets a compensation learning value when the reference value is smaller than the reference value.

When the compensation learning value is set, the fuel injection amount learning value is calculated, and the starting fuel amount is calculated using the calculated fuel injection amount learning value.

The latter technique detects whether the ignition switch is on, input values such as atmospheric pressure and coolant temperature, and engine cranking state, and compares the engine cranking time with a reference time set according to the coolant temperature so that the engine cranking time is greater than the set time. If it is large, it is detected whether the engine speed decrease occurs before the target speed is reached during the engine speed increase.

When the engine speed decrease occurs, the engine speed reduction amount is compared with the engine speed reduction amount for determining the low vaporization fuel, and according to the comparison result, the correction of the low vaporization fuel amount, the fuel warm-up increase correction, and the acceleration increase correction are performed immediately after starting.

The above-described conventional technique is a method of setting a reference value of the engine speed at start-up and monitoring a rise of the engine speed to set a low quality fuel compensation value, thereby indirectly diagnosing a change in the engine speed, thereby accurately estimating fuel amount compensation. There is a difficulty that cannot be done.

In addition, there is a problem in that fuel compensation cannot be realized for the high-efficiency fuel because it is a technology that can only support the low-vaporization fuel.

In addition, since the characteristics of the fuel must be determined indirectly according to the change of the engine speed, the starter logic configuration is complicated, and a lot of time and effort are required to set the control data, so that the development period is long and the application to the system is complicated. have.

The present invention has been invented to solve the above problems, the purpose of which is to open and adjust the PCSV (Purge Control Solenoid Valve) which is installed in the purge line connecting the fuel tank and the engine immediately before starting the engine to adjust the evaporation pressure of the fuel To monitor.

In addition, the present invention calculates the correlation coefficient for fuel volatility from the air-fuel ratio change detected by the oxygen sensor for the evaporation pressure of the fuel in the fuel tank immediately before starting the engine, and controls the amount of fuel supplied at startup in accordance with the correlation coefficient will be.

An apparatus for controlling starting fuel amount of an engine according to a feature of the present invention for realizing the above object includes an engine as a power source; Fuel tank; A catalyst for purifying exhaust gas emitted from the engine; A water temperature sensor detecting a temperature of the cooling water; A purge control solenoid valve installed in the purge line of the engine and the fuel tank to purge the evaporated fuel from the fuel tank,

An oxygen sensor installed at the front end of the catalyst and detecting an air-fuel ratio change according to the opening of the purge control solenoid valve when a monitoring condition for controlling the starting fuel amount is satisfied;

The fuel volatility determination condition according to the engine cooling condition is determined in the starting preparation condition, the air-fuel ratio change is measured by the oxygen sensor with the purge control solenoid valve open, and the fuel amount at start-up is determined by determining the correction amount in the air-fuel ratio change factor map. It includes a control unit for controlling.

Starting fuel amount control method of the engine according to a feature of the present invention,

Determining a fuel volatility determination condition according to the engine cooling state when the engine start preparation condition is detected;

Measuring an air-fuel ratio change through an oxygen sensor after opening the purge control solenoid valve;

Extracting a correction value by applying the measured value of the air-fuel ratio change amount to a fuel amount correction factor map including a correlation coefficient of fuel evaporation pressure;

And applying the correction value extracted according to the air-fuel ratio change amount to the starting fuel amount.

According to the above-described configuration, the present invention can measure the fuel volatility directly through the oxygen sensor immediately before starting the engine, so that the amount of fuel supplied to the engine can be accurately calculated. By inducing it is effective to stabilize the emission of the exhaust gas.

In addition, the present invention, by monitoring the amount of air-fuel ratio changes by performing the fuel amount control at start-up by distinguishing the low volatile fuel, high volatile fuel and the normal level of volatile fuel according to the evaporation pressure of the fuel, the fuel amount control is easily performed There is.

In addition, since the present invention provides substantial monitoring of the fuel characteristics, it is not necessary to configure a separate logic for identifying the fuel characteristics, thereby simplifying the start-up logic configuration and reducing the possibility of a software problem, thereby improving the marketability of the engine. And the mass production material is expected to be improved.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

Since the present invention can be implemented in various different forms, the present invention is not limited to the exemplary embodiments described herein, and parts not related to the description are omitted in the drawings in order to clearly describe the present invention.

1 is a view showing a schematic configuration of a starting fuel amount control apparatus of an engine according to an embodiment of the present invention.

The present invention includes an engine 101, a fuel tank 102, a catalyst 103, a water temperature sensor 104, an oxygen sensor 105, a PCSV 106, and a controller 107, which are power sources.

The catalyst 103 is connected to the engine 101 through a manifold manifold, and purifies harmful substances such as NOx, HC, and CO included in the exhaust gas discharged from the engine 101 through oxidation and reduction.

The water temperature sensor 104 detects the temperature of the coolant circulating in the engine 104 and provides the information to the controller 107.

The oxygen sensor 105 is installed in front of the catalyst 103 with a linear oxygen sensor, which is a wide band oxygen sensor, and when the PCSV 106 is opened when the monitoring condition for starting fuel amount control is satisfied. The air-fuel ratio change amount is detected and provided to the control unit 107.

The PCSV 106 is installed in the purge lines of the engine 101 and the fuel tank 102, and the opening and closing of the valve is adjusted according to the control of the controller 107 to supply the fuel evaporated from the fuel tank 102 to the engine 104. By purging with, the pressure inside the fuel tank 102 is kept stable.

The controller 107 detects the external air temperature and the temperature of the coolant to determine the fuel volatility determination condition by detecting the outside temperature and the temperature of the coolant, and forcibly opens the PCSV 106 to grasp the volatilization characteristics of the fuel. By measuring the air-fuel ratio change for a predetermined time with respect to the evaporation pressure of the fuel generated in the fuel tank 102 for a predetermined time and then compensates at the start of the engine 101 by using the air-fuel ratio change as a correlation coefficient of the fuel evaporation amount By applying the value, the starting fuel amount is controlled to the optimum value.

The starting preparation condition is a condition in which a driver is occupied in a parked vehicle in a state where door lock / unlock and door open / close are detected.

The control unit 107 performs fuel increase correction for fuels with low volatility for stable combustion at start-up of the engine 101 according to the monitoring results, and on the contrary, fuel loss correction for high volatility fuels.

An operation of controlling the starting fuel amount in the present invention including the above function will be described in detail with reference to FIG. 2.

The controller 107 detects vehicle state information such as door lock / unlock, door open / close, outdoor temperature, and coolant temperature while the engine 101 is kept off (S101), and then the door unlock is detected. (S102) It is determined whether the door open / close is detected (S103).

That is, it is determined whether the starting preparation condition is satisfied by determining whether the driver has boarded the vehicle in the parking state.

In the determination of S102 and S103, if the start preparation condition is not satisfied, the standby state is continuously maintained. If the start preparation condition is satisfied, the result of calculating the temperature of the coolant at the outside temperature is less than the first reference temperature Temp1. In operation S104, if the temperature is less than the first reference temperature, it is determined whether the cooling water temperature is less than the second reference temperature Temp2 (S105).

If the cooling water temperature is less than the second reference temperature in the determination of S105, it is determined that the engine 101 is sufficiently cooled.

As described above, the cooling state of the engine 101 is determined by comparing the outside air temperature and the cooling water temperature with the set first and second reference temperatures, and the fuel volatility determination condition according to the cooling state is determined.

When the cool state of the engine 101 and the fuel volatility determination condition are determined, the control unit 107 heats the oxygen sensor 105 to enter the activation mode (S106), and opens the PCSV 106 in the fuel tank 102. The air-fuel ratio change is also increased in proportion to the magnitude of the generated fuel evaporation pressure (S107).

At this time, the control unit 107 monitors the signal of the oxygen sensor 105 (S108), and calculates the air-fuel ratio change over time (S109).

As shown in FIG. 3, the air-fuel ratio change amount Δλ over time has different values, such as Δλ 1, Δλ 2 and Δλ 3, depending on the fuel evaporation pressure (evaporation amount).

In the process of monitoring the air-fuel ratio change amount Δλ as described above, it is determined whether the start-up of the engine 101 is detected (S110), and if the start-up is not detected, the elapsed time after opening the PCSV 106 is set. It is determined whether the time DELTA t is exceeded (S111).

If the elapsed time exceeds the predetermined time Δt in the determination of S111, the controller 107 closes the PCSV 106, simultaneously turns off the heating of the oxygen sensor 105, and ends the air-fuel ratio change amount (S112). ).

However, if the start-up of the engine 101 is detected in the determination of S110, the PCSV 106 in the open state is closed to minimize the fuel effect of the purge line at start-up, and the elapsed time after the opening of the PCSV 106 ( The air-fuel ratio change amount Δλ for Δt 'is calculated (S114), and it is determined whether or not the correction value is applied (S115).

If the correction value is not applied in S115, the air-fuel ratio change Δλ previously executed is applied as the fuel amount correction value at the start of the engine 101, and if the correction value is applied, the air-fuel ratio calculated for the elapsed time Δt 'is applied. The correction value is determined from the fuel amount correction factor map configured as shown in Table 1 with respect to the change amount Δλ, and then applied to the fuel amount at start-up (S113).

The fuel amount correction factor map for the air-fuel ratio change Δλ is configured as shown in Table 1 as a correlation coefficient with the fuel evaporation pressure.

Δλ1 Δλ2 △ λ3 … … -30 ℃ AD_TI1 AD_TI2 AD_TI3 … … -10 ℃ AD_TI4 AD_TI5 AD_TI6 … … 10 ℃ AD_TI7 AD_TI8 AD_TI9 … … 20 ℃ AD_TI10 AD_TI11 AD_TI12 … …

Since the air-fuel ratio change amount Δλ has a different value depending on the fuel evaporation pressure (evaporation amount), the air-fuel ratio change amount Δλ can be used as a fuel compensation value when the engine 101 is started using the correlation coefficient.

In other words, if it is determined that the fuel is low in volatile fuel for stable combustion at start-up, the fuel increase correction is executed.

For example, start-up fuel amount = (basic fuel amount) * [1 + (AD_TIn) * constant 1] to determine and control, warm-up fuel amount = (basic fuel amount) * [1 + (AD_TIn) * Constant 2] and control it by controlling the amount of acceleration fuel = (basic fuel amount) * [1 + (AD_TIn) * constant 3 / time constant].

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It is included in the scope of rights.

1 is a view showing a schematic configuration of a starting fuel amount control apparatus of an engine according to an embodiment of the present invention.

2 is a flowchart illustrating a starting fuel amount control procedure of an engine according to an exemplary embodiment of the present invention.

3 is a diagram illustrating evaporation performance determination in fuel amount control at engine start according to an exemplary embodiment of the present invention.

<Explanation of symbols for main parts of the drawings>

101: engine 102: fuel tank

103: catalyst 104: water temperature sensor

105: oxygen sensor 106: PCSV (Purge Control Solenoid Valve)

107: control unit

Claims (8)

Power source engine; Fuel tank; A catalyst for purifying exhaust gas emitted from the engine; A water temperature sensor detecting a temperature of the cooling water; A purge control solenoid valve installed in the purge line of the engine and the fuel tank to purge the evaporated fuel from the fuel tank, An oxygen sensor installed at the front end of the catalyst and detecting an air-fuel ratio change according to the opening of the purge control solenoid valve when a monitoring condition for controlling the starting fuel amount is satisfied; The fuel volatility determination condition according to the engine cooling condition is determined in the starting preparation condition, the air-fuel ratio change is measured by the oxygen sensor with the purge control solenoid valve open, and the fuel amount at start-up is determined by determining the correction amount in the air-fuel ratio change factor map. A control unit for controlling; Starting fuel amount control device of the engine comprising a. The method of claim 1, The oxygen sensor is applied to a linear oxygen sensor, the starting fuel amount control of the engine to provide a measurement of the wide band. The method of claim 1, The control unit controls the starting fuel amount of the engine as a result of measuring the air-fuel ratio change amount, the fuel having low volatility executes the fuel increase correction, and the high volatility fuel performs the fuel loss correction. The method of claim 1, The engine-fuel ratio control device of the engine is set to the air-fuel ratio change amount correction factor map set in the control unit as a correlation coefficient with the fuel evaporation pressure. Determining a fuel volatility determination condition according to the engine cooling state when the engine start preparation condition is detected; Measuring an air-fuel ratio change through an oxygen sensor after opening the purge control solenoid valve; Extracting a correction value by applying the measured value of the air-fuel ratio change amount to a fuel amount correction factor map including a correlation coefficient of fuel evaporation pressure; Applying a correction value extracted according to the air-fuel ratio change amount to the starting fuel amount; Starting fuel amount control method of the engine comprising a. The method of claim 5, The engine starting preparation condition is determined by detecting a door lock / unlock and a door open / close. The method of claim 5, And the fuel volatility determination condition is determined using an outside temperature and a temperature of cooling water. The method of claim 1, If the engine start-up is not detected within a predetermined time in the process of detecting the change in the air-fuel ratio, the method of controlling the starting fuel amount of the engine to close the purge control solenoid valve, turn off the heating of the oxygen sensor and then stop the detection of the air-fuel ratio change .

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