KR100535383B1 - Idle purge controlling method of vehicle - Google Patents

Abstract

In controlling the idle purge in the vehicle to maximize the purge amount of the evaporated gas (HC) collected in the canister, and to follow the idle target rotation speed,

Determining whether the engine is in the purge mode and satisfying the stop idle condition while the engine is kept on, and if the above conditions are met, the ISA opening amount is '0', and the actual rotation speed is set by the excessive supply of air through the purge valve. Determining whether the rotational speed exceeds the rotational speed; and if the actual rotational speed exceeds the target rotational speed, gradually recognizing and recovering the idle ignition timing step by step to follow the target rotational speed, and wherein the actual rotational speed is the target rotational speed. If exceeded, the process of performing a normal purge control is included.

Description

Idle PURGE CONTROLLING METHOD OF VEHICLE}

The present invention relates to an idle purge control in a motor vehicle, and more particularly, to an idle purge control method for maximizing a purge amount of an evaporated gas (HC) collected in a canister and following an idle target rotational speed.

In general, North America's tightened evaporative gas regulations (currently Europe also introduces similar legislation) tend to maximize the canister purge as much as possible when idle and driving.

As can be seen in FIG. 6, in the case of automobiles, in order to prevent air pollution, an evaporation gas (HC) harmful to a human body generated in the fuel tank (1) is collected in the canister (2), and then the collected evaporation gas (HC). ) Is supplied to the engine surge tank 4 through the purge valve 3 to enter the combustion chamber.

Since the boil-off gas HC is mostly generated by the volatilization of the fuel remaining in the fuel tank, the vaporized gas HC is well collected in the canister, and the collected boil-off gas HC is properly supplied to the engine so that It is important to properly prevent saturation.

In accordance with the regulation of boil-off gas (HC), which is very strict in North America and Europe, the control is carried out to maximize the purge amount of the canister purge valve, that is, the opening degree of the purge valve.

In order to control the purge of the boil-off gas HC collected in the canister as described above, the amount of boil-off gas HC collected in the canister is determined by determining a fuel amount feedback level determined according to the oxygen content concentration of the exhaust gas detected from the oxygen sensor. (Density) is determined, and the opening degree of the purge valve is determined and controlled accordingly.

The opening degree of the purge valve typically depends on the coolant temperature, engine speed, engine load, fuel level learning and fuel level feedback gain, but the amount of purge at idle is limited to the fuel level feedback level. This is the main factor.

Opening control of purge valve according to fuel level feedback level is as follows.

As can be seen in FIG. 7, as the fuel feedback feedback gain is smaller than " 1.0 " and the concentration (amount) of the boil-off gas HC collected in the canister increases, the deterioration of stability due to the purge gas on the engine is prevented. In order to reduce the opening degree of the purge valve.

On the contrary, as the concentration (amount) of the boil-off gas (HC) trapped in the canister becomes thinner and the fuel feedback feedback gain is larger than "1.0", the opening degree of the purge valve is increased to increase the purging amount and to be controlled to be rapidly purged. do.

As described above, in the conventional idle purge control method, when the concentration of the boil-off gas (HC) collected in the canister is not rich or idle, there are cases in which the purge valve is opened almost 100% to maximize the purging amount. At this time, the amount of air to the surge tank through the purge valve is too large, even if the idle speed actuator closes to almost zero, the idle target rotational speed cannot be followed, so that the idle rotational speed is maintained and the idle stability becomes worse. .

When it is detected that the idle target rotation speed cannot be tracked due to excess idle air, the existing method reduces or decreases the amount of air through the purge valve by opening or closing the purge valve. This causes a problem of increasing the emission of the boil-off gas.

The present invention has been invented to solve the above problems, the object of which is to maximize the purge amount in the engine idle conditions and to follow the idle target rotation speed.

In other words, if the actual rotation speed exceeds the target speed even though the ISA opening is '0' due to the large amount of purging, the engine torque is reduced through the gradual perception of the ignition period and the idle air volume is increased to finally increase the target speed. To follow.

The present invention for realizing the above object comprises the steps of determining whether the engine is in the purge mode and the start idle state is maintained on; Determining whether the ISA opening amount is '0' if the above condition is satisfied, and whether the actual rotation speed exceeds the target rotation speed by an excessive supply of air through the purge valve; When the actual rotation speed exceeds the target rotation speed, retarding and recovering the idle ignition timing step by step to follow the target rotation speed; If the actual rotation speed exceeds the target rotation speed includes the step of performing a normal purge control.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As can be seen in FIG. 1, the idle purge control device according to the present invention includes an oxygen sensor 10, a coolant temperature sensor 20, a crank position sensor 30, an intake air amount sensor 40, and an ISA opening degree detection unit 50. And an ECU 60 and a purge valve 70, the oxygen sensor 10 detects the concentration of oxygen contained in the exhaust gas and provides the ECU 60 with feedback level information for fuel amount correction.

The cooling water temperature sensor 20 detects temperature information of the cooling water and provides the cooling water temperature information to the ECU 60 as information for determining the idle.

The crank position sensor 30 detects the rotation speed of the crankshaft and provides it to the ECU 60 as information for idle determination.

The intake air amount sensor 40 detects the amount of air sucked into the combustion chamber through the intake manifold and provides information on the amount of the air to the ECU 60.

The ISA opening degree detecting unit 50 detects information on the opening amount of the idle speed actuator in the idle state and provides the information to the ECU 60.

The ECU 60 calculates each condition detected from each of the above sensors through a set algorithm as a total control means in a vehicle, and then controls the overall operation of the engine control, and the evaporation captured by the canister in the idle state of the idle state. Purge control of gas HC and perception control of ignition timing are performed.

The purge valve 70 adjusts the opening degree according to the control signal applied from the ECU 60 to purge the boil-off gas HC collected in the canister into the combustion chamber.

Operation of performing the idle purge control through the configuration of the present invention including the function as described above is as follows.

The ECU 60 determines whether the engine is currently maintained on by analyzing the signal detected from the crank position sensor 30 (S101).

When it is determined that the engine maintains the start-up in the above state, the signal of the oxygen concentration contained in the exhaust gas detected from the oxygen sensor 10, the temperature of the coolant detected from the coolant temperature sensor 20, and the crank position sensor ( 30 is purged of the boil-off gas HC collected in the canister by analyzing the engine speed detected by 30), the information on the intake air amount detected by the intake air amount sensor 40, and the opening rate of the ISA detected by the ISA opening degree detection unit 50. In mode, it is determined whether the stop idle condition is satisfied (S102).

If the purge mode of the boil-off gas HC collected in the canister is determined to satisfy the stop idle condition, the opening degree of ISA is maintained at '0', and the actual rotation speed exceeds the target rotation speed, that is, the purge valve. It is determined whether the excess air amount is being sucked through (S103).

When it is determined that the excess air amount is sucked through the purge valve and the actual rotation speed exceeds the target rotation speed, the purge amount (from the map table of the memory means) Perception of the ignition timing according to the < RTI ID = 0.0 > 1) < / RTI >

The amount of purge mentioned above ) Is '0' under battery reset or start-up conditions.

The amount of purge above The reason for reading the perception of the ignition timing is because the ignition timing is an important factor in determining the engine torque.

Therefore, the idle ignition timing shows a decrease / increase of torque when advancing / perceiving based on the reference ignition timing, and as shown in FIG. 4, the idle torque can be controlled according to the target rotational speed. Significantly perceived by the child as the reference ignition timing.

As above, purge amount ( Purge amount after a predetermined time, e.g. ), Correct the ignition timing perception as follows (S105).

The above ignition timing correction value Fourth constant value.

If the correction value has the minimum value while the ignition timing perception correction is in progress as described above, the final ignition timing perception amount is stored in the memory table (S106).

Subsequently, the ignition timing is controlled by calculating the ignition timing in consideration of each detected condition as described below (S107), and the ISA opening amount detected in the state where the ignition timing is controlled as described above is greater than the set second constant value. It is determined whether the state of maintaining the state or the state of the ISA opening degree after the previous condition is satisfied is larger than the set first constant value (S108).

The above ignition timing calculation

If it is determined in S108 that the ISA opening amount through the control of the ignition timing perception is kept larger than the set second constant value or the ISA opening amount after the last transition condition is satisfied is greater than the set first constant value, the ISA opening degree is determined. It is determined whether the amount is larger than the eighth constant value set under the condition of maintaining the idle ignition timing (S109).

When it is determined that the ISA opening amount exceeds the eighth constant, the ignition timing according to the purge amount after a predetermined time set, for example, the sixth constant second is determined as follows (S110).

Ignition time crust is 7th constant value

After the ignition timing perception correction is performed in step S110, if the ignition timing perception amount has the minimum value, the corresponding correction value is stored in the memory means (S111), and the operation of the ignition timing is controlled according to each state condition of the engine detected as follows. (S112).

Calculation of ignition timing

to be.

When the ISA opening degree is not '0' in S103 or when it is determined that the actual rotation speed does not exceed the target rotation speed, normal purge control is performed (S113), and the ignition timing is determined according to each engine condition detected as follows. Operation control (S114).

Normal ignition timing operation control

In the above ignition timing calculation, θb: basic ignition timing value, θfc: fuel cutoff ignition timing value, θwt: water temperature correction value, θat: intake temperature correction value, θi: idle stabilization correction value, θk: knock perception correction value, θwth : High temperature perception correction value, θac: Perception correction value when air conditioner is off, θatknk: High intake temperature perception correction value, θshock: Acceleration shock perception correction value, θnd: ND shift perception correction value at low water temperature, θtcl: Traction control perception correction value, θbp: Atmospheric pressure correction value.

The above description will be supplemented with reference to FIG. 3 as follows.

If the ISA opening amount is '0' and the actual rotation speed is determined to be an excess air supply through the purge valve exceeding the target rotation speed, as shown in the drawing, the idle opening stepwise becomes larger than the set second constant value. The control reference ignition timing is perceived by the set value at each set time interval.

The perceived reference ignition timing is then stored in the memory means for application to the next idle condition and purge mode.

Clipping to the lower limit of the perception ignition timing prevents impairment of engine stability if too late.

In addition, when the ISA opening amount detected through the perception control of the ignition timing is larger than the set second constant value, the ignition timing is no longer performed, and the current idle until the ISA opening amount becomes smaller than the first constant value set again. Please note the timing of ignition.

If the ISA opening amount is detected to be larger than the set eighth constant value, the ignition timing is restored by the set seventh constant value at a predetermined time interval, for example, the sixth constant second interval.

As described above, when the idle control reference ignition timing is delayed, the torque decreases, so that the air amount is relatively increased. As a result, the control of the idle ignition timing and the target idle air volume is performed as shown in FIG. Nevertheless, when the actual rotation speed exceeds the target rotation speed, if the control ignition timing is perceived step by step, the engine torque decreases and the idle air amount increases, so that the target rotation speed can be followed.

 As described above, the present invention facilitates North American / European enhanced evaporative gas regulation through stable control of idle purge and improves idle stability to increase operability quality.

1 is a block diagram illustrating an idle purge control device according to the present invention;

2 is a flow diagram of one embodiment for performing idle purge control in accordance with the present invention.

3 is a transition diagram for perception of idle control ignition timing in idle purge control according to the present invention.

Figure 4 is a graph of the engine torque versus ignition timing in the idle purge control according to the present invention.

5 is a graph showing a relationship between idle ignition timing and target idle air consumption in idle purge control according to the present invention;

6 is a block diagram of a general idle fuzzy control structure applied to a vehicle.

7 is a graph showing a relationship between fuel amount feedback gain and opening degree of a purge valve in a conventional idle purge control.

Claims (2)

delete Determining whether the engine is in the purge mode and the idle state is satisfied while the engine is started on; Determining whether the ISA opening amount is '0' if the above condition is satisfied, and whether the actual rotation speed exceeds the target rotation speed by an excessive supply of air through the purge valve; When the actual rotation speed exceeds the target rotation speed, retarding and recovering the idle ignition timing step by step to follow the target rotation speed; The idle purge control method comprising the step of performing a normal purge control when the actual rotation speed exceeds the target rotation speed.