KR20020049320A - An idle control method for a inertial moving vehicle - Google Patents

Abstract

PURPOSE: An idle control method during running of a vehicle is provided to prevent the engine stall and undershoot of the engine RPM by maintaining the real engine RPM similar to the filtered engine RPM. CONSTITUTION: An idle control method during running of a vehicle includes the steps of : judging that the idle is on deceleration(15); if the idle is on deceleration, judging that a clutch is on-state by calculating the change rate of the engine RPM(18); if the clutch is on-state, filtering the engine RPM in low pass(19); calculating the difference of the real engine RPM and the filtered engine RPM(20); judging that the difference exceeds a fixed value(21); and if the difference exceeds a fixed value, compensating the air amount in proportion to the difference(22).

Description

ANIDLE CONTROL METHOD FOR A INERTIAL MOVING VEHICLE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method in a case where a vehicle is running in a throttle off state (idle state), and more particularly to an air volume control in a coasting state.

The electronic control unit of the vehicle receives the vehicle speed, the engine RPM, the signal of the throttle position sensor (TPS), and monitors the state of the vehicle. If the opening of the vehicle is recognized as the idle state, the idle control, that is, the amount of air and Perform ignition timing control.

Next, with reference to the drawings, the control of the air amount, among the conventional idle control, will be described.

1 is a flow chart of an idle control method according to the prior art.

First, the electronic control unit receives a vehicle speed, RPM, TPS signal, etc. from various sensors to determine whether the monitoring condition corresponds (step 1). This is a monitoring condition when the throttle is off, the vehicle is not stationary and is clutch-on.

If the monitoring condition is met, the electronic control unit performs air volume control (step 2), and if not, idle control is not performed. The air volume control first releases the dashpot air volume (Q_dash) (step 3), sets the base air volume (Q_base) (step 4), and then reads out the learning air volume (Q_adap) (step 5) to determine the total air volume. The operation proceeds in the order of operation (step 6). Here, the dashed air amount Q_dash is an amount of air through an idle speed actuator (ISA) set according to the TPS opening degree, and when the TPS recognizes the idle amount, the dashed air amount is gradually released. The basic air volume is supplied through ISA as the air volume set according to the cooling water temperature. The learning air amount is an amount of air that is learned only when the coolant is sufficiently warmed and the vehicle is stopped, and compensates the difference between the actual RPM and the target RPM in the idle state. The total air amount is the sum of the dashed air amount (Q_dash), the base air amount (Q_base), and the learning air amount (Q_adap).

Next, it is determined whether the RPM is smaller than the threshold (step 7). If the RPM is less than the threshold value, the ISA air volume is increased (step 8), and if it is greater than the threshold value, the idle control is terminated. The RPM threshold value is around 500 times / minute.

In a conventional manual transmission vehicle controlled in this manner, the engine RPM is controlled to return to the idle target RPM in the stopped state when the clutch is pressed during the throttle off state, i.e., the idle state. However, if the clutch pedal is depressed during the deceleration due to the throttle-off, the engine RPM may suddenly decrease while falling to a lower RPM than the idle target RPM, or the engine may stall when the engine is stalled. Therefore, during the deceleration due to the throttle-off, dashed bean air volume control is performed through ISA to prevent a sudden decrease of the air volume. The dashed bean controlled air volume is controlled to decrease to O with a constant slope over time. However, when the clutch is pressed in the state where the dashed air volume control is finished, there is no sudden change of air volume, so starting may be turned off or RPM may be severely lowered, resulting in engine relief. That is, if the dashed air volume is released, the total air volume is represented as the sum of the basic air volume and the air volume learned in the previous stop state. When the air volume learning is excessively progressed in the negative direction, the engine stall occurs due to the lack of the total air volume. .

The technical problem to be achieved by the present invention is to provide an idle control method that can prevent the engine is stalled due to a sudden decrease in the amount of air during the other line of the vehicle.

1 is a flow chart of an idle control method according to the prior art,

2 is a flowchart of an idle control method according to an embodiment of the present invention,

Figure 3a is a graph of the engine RPM and IAS air amount and dashed air amount when idle control according to the prior art,

Figure 3b is a graph of the engine RPM and IAS air amount and dashed air amount when idle control in accordance with an embodiment of the present invention.

In order to solve this problem, the present invention low-pass filter the engine speed to correct the amount of air in proportion to the difference between the filtered engine speed and the actual engine speed.

Specifically, the first step of determining whether or not the deceleration idling, the second step of determining whether the clutch on state by calculating the engine speed change amount when it is determined that the deceleration idling in the first step, the clutch on state in the second step The third step of low pass filtering the engine speed, the fourth step of calculating a difference between the actual engine speed and the engine speed filtered in the third step, and the difference calculated in the fourth step is determined by a predetermined value. The idle control method of the other vehicle is provided, comprising the fifth step of determining whether the excess is exceeded and the sixth step of correcting the amount of air in proportion to the difference when the difference calculated in the fifth step exceeds the predetermined value.

In this case, the first step may be a step of determining whether or not deceleration idle by measuring the vehicle speed variation per 100msec and the TPS voltage, and the third step is the filtered engine speed Nf (i), the actual engine speed When N is Na (i) and the filtering constant is Kf, Nf (i) satisfying Nf (i) = Kf × Nf (i) + Na (i) × (1-Kf) may be obtained.

Next, the idle control method of the vehicle in accordance with the embodiment of the present invention will be described with reference to the accompanying drawings.

2 is a flowchart of an idle control method according to an exemplary embodiment of the present invention.

First, it is determined whether the deceleration children. The method for determining whether decelerating children is as follows. From the TPS voltage, it is determined whether or not the vehicle is in the idle state (step 11). If it is not in the idle state, the logic is terminated. If the idle state is detected, the speed Vs of the vehicle is read (step 12). At this time, if the TPS voltage is about 0.3V, it is determined as idle. Next, it is determined whether or not the speed Vs of the vehicle is zero (i.e., stopped) (step 13), and the logic is terminated if it is stopped, and if the vehicle is not stopped, i. (Step 14). At this time, if the vehicle speed change amount? Vs per 100 msec is equal to or greater than the predetermined value threshold 1, it is determined as the deceleration state (step 15). That is, when the TPS voltage is about 0.3V and the vehicle speed change amount? Vs per 100msec is equal to or more than a predetermined value, it is determined as deceleration idle.

The next engine speed (RPM, Na) is read (step 16). The engine speed change amount ΔNa per 10 msec is calculated using the read engine speed Na (step 17). ΔNa is expressed by the following formula.

ΔNa = Na (i)-Na (i-10 msec)

If? Na is greater than or equal to the threshold 2, it is determined to be in the clutch on state (step 18). If the? Na is less than or equal to the predetermined value, the following logic is performed.

Next, when it is determined that the clutch is in the ON state, the engine speed Na is low-pass filtered (step 19). At this time, the filtering is performed linearly by the following equation. In Equation 2, Nf is the filtered engine speed and Kf is the filtering constant.

Nf (i) = Kf × Nf (i) + Na × (1-Kf)

Then, the difference between the actual engine speed Na and the filtered engine speed Nf is calculated. That is, DELTA N_diff expressed by the following expression (3) is obtained.

ΔN_diff = Nf-Na

Next, it is determined whether the obtained DELTA N_diff exceeds a predetermined value (threshold 3) (step 21), and when it exceeds, air volume correction is performed (step 22). The air amount correction is to supply additional air of the amount Q_air represented by the following equation (4).

Q_air = k × ΔN_diff

In this way, by correcting the air volume in proportion to the difference between the actual engine speed and the filtered engine speed, it is possible to maintain the actual engine speed at a value similar to the filtered engine speed so that the undershoot of the engine stall or engine speed ( undershoot) can be prevented.

Figure 3a is a graph of the engine RPM and the IAS air amount and dashed air amount when the idle control according to the prior art, Figure 3b is the engine RPM and IAS air amount and dash when the idle control in accordance with an embodiment of the present invention It is a graph of red bean air volume.

In FIG. 3B, unlike FIG. 3A, it can be seen that undershoot of the engine RPM does not occur.

According to the present invention, it is possible to prevent the occurrence of an engine stall or an undershoot of the engine speed in the deceleration idle state.

Claims (3)

A first step of determining whether deceleration idles, A second step of determining whether the clutch is on by calculating an engine speed change amount when it is determined as deceleration idle in the first step, A third step of low-pass filtering the engine speed when it is determined in the second step as the clutch on state, A fourth step of calculating a difference between the actual engine speed and the engine speed filtered in the third step, A fifth step of determining whether the difference calculated in the fourth step exceeds a predetermined value, A sixth step of correcting the amount of air in proportion to the difference if the difference calculated in the fifth step exceeds the predetermined value; Children control method of the other vehicle comprising a. In claim 1, In the first step, the idle control method of the other vehicle determines whether or not the deceleration idle by measuring the vehicle speed variation per 100msec and the TPS voltage. In claim 1, In the third step, when the filtered engine speed is Nf (i), the actual engine speed is Na (i), and the filtering constant is Kf, Nf (i) = Kf × Nf (i) + Na (i). An idle control method for another vehicle, which is a step of obtaining Nf (i) satisfying 占 (1-Kf).