KR20030087705A - Method of protecting engine stall for vehicles - Google Patents

Abstract

PURPOSE: A method is provided to achieve improved stability of travel by preventing an engine stall caused due to the faults and failure of contact of the crank position sensor. CONSTITUTION: A method comprises a step(110) of judging whether a vehicle engine is in operation; a step(120) of performing a crank position sensor learning if the vehicle engine is in operation; a step(130) of judging whether the signal output from the crank position sensor changes between the cam position sensor rising edges; a step(140) of judging whether the crank position sensor learning has completed, if no change exists in the previous step; a step(150) of calculating a virtual crank position sensor edge by multiplying the crank position sensor time fraction and the time taken for one revolution of the cam position sensor if the crank position sensor learning has completed, and identifying each cylinder by permitting the calculated virtual crank position sensor tooth with the cam position sensor; and a step(160) of controlling the fuel quantity and delay controlling the ignition timing.

Description

How to prevent engine stall in a vehicle {METHOD OF PROTECTING ENGINE STALL FOR VEHICLES}

The present invention relates to a method for preventing engine stall of a vehicle, and more particularly, to a method for preventing engine stall of a vehicle for preventing engine stall caused when a crank position sensor contact failure occurs.

As shown in FIG. 1, conventionally, a crank position sensor and a cam position sensor are synchronized to recognize (divided) each cylinder, and to determine an ignition timing based on this. Calculation was performed to perform ignition and injection.

As a result, when the crank position sensor is broken (disconnection, noise, etc.), the engine is not recognized because the cylinder is not recognized, and thus, the engine is stopped, that is, engine stall is generated.

As described above, when the crank position sensor fails, the engine stall is one of field problems of the vehicle, and when the crank position sensor contact is poor, the error monitor time is 2 seconds, and no error is stored. The vehicle often stalls. However, if the monitor time is shortened, there is a risk that errors are stored too frequently due to noise, etc., so the monitor time must be adhered to.

The present invention has been made to solve the above problems, and provides an engine stall prevention method of a vehicle which prevents engine stall when a crank position sensor contact is poor and detects a crank position sensor error normally. have.

1 is a block diagram schematically showing a system configuration for explaining an engine stall generation of a general vehicle.

Figure 2 is a schematic flowchart showing sequentially a method for preventing engine stall of a vehicle according to the present invention.

3 is a block diagram schematically illustrating a system configuration to which a method for preventing engine stall of a vehicle according to the present invention is applied.

FIG. 4 is a schematic flowchart illustrating a learning subroutine of the crank position sensor in FIG. 2. FIG.

5 is a diagram illustrating a normal signal diagram of a crank position sensor and a cam position sensor of a real vehicle.

6 is a signal diagram showing the relationship between the crank position sensor and the cam position sensor.

Engine stall prevention method of the vehicle of the present invention for achieving the above object, (a) determining whether the engine of the vehicle is in operation; (b) if it is determined in step (a) that the engine is running, performing crank position sensor learning; (c) determining that there is no change in crank position sensor signal between the cam position sensor rising edges; (d) determining whether crank position sensor learning is completed when the condition in step (c) is satisfied; (e) If it is determined in step (d) that the crank position sensor learning is completed, the crank position sensor time fraction is multiplied by the time taken for one rotation of the cam position sensor to calculate the virtual crank position sensor edge, and the calculated virtual Synchronizing a crank position sensor tooth with a cam position sensor to identify each cylinder; (g) the fuel amount is controlled in a normal manner, and the ignition timing is normally controlled by the perception by α °.

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

2 is a schematic flowchart sequentially illustrating a method for preventing engine stall of a vehicle according to the present invention, and FIG. 3 is a schematic block diagram showing a configuration of a system to which an engine stall prevention method of a vehicle according to the present invention is applied. The figure is shown.

Referring to each of the drawings, the engine stall prevention method of the vehicle according to the present invention first determines whether the engine of the vehicle is in operation (step 110).

That is, cranking or determining whether the engine is running, and all monitors are meaningful from the time when the engine is operated.

Next, if it is determined in step 110 that the engine is in operation, crank position sensor learning is performed (step 120).

Then, it is determined whether there is no change in the crank position sensor signal between the cam position sensor rising edges (step 130).

That is, in order to prevent engine stall, the crank position sensor error should be detected as soon as possible, as shown in FIG. 5 to be described later. There must be a signal change of the crank position sensor between the cam position sensor rising edges. Use this to detect crank position sensor errors as soon as possible.

If the condition in step 130 is satisfied, that is, if there is no signal change, the temporary error code is turned on and it is determined whether the crank position sensor learning is completed (step 140).

If it is determined in step 140 that the crank position sensor learning is completed, the crank position sensor time fraction is multiplied by the time taken for one rotation of the cam position sensor to calculate the virtual crank position sensor edge, and the calculated virtual The crank position sensor tooth is synchronized with the cam position sensor to identify each cylinder of the engine (step 150).

Subsequently, the fuel amount is controlled in a normal manner, the ignition timing is normally controlled by α °, and the present control ends (step 160).

On the other hand, performing the crank position sensor learning in step 120, as shown in Figure 4, first, after the engine start a second has elapsed, the engine speed (rpm), the engine load is in a certain range [(b <engine Number of revolutions <c), (d <engine load <e)], the coolant temperature is above a predetermined temperature (coolant temperature> f), the amount of change in the Throttle Position Sensor (TPS) is below a certain amount (the amount of change in the TPS <g), and the crank It is determined whether the position sensor and the cam position sensor satisfy both normal conditions, and whether the crank position sensor learning completion bit is off (step 121).

Then, the time from the measured rising edge of the cam position sensor to each falling and rising edge of the crank position sensor is measured, and at the same time, the time taken for one rotation of the cam position sensor is measured. )

In addition, the measured time to each falling and rising edge of the crank position sensor is divided by one crank position sensor rotation time (step 125).

Subsequently, the calculated crank position sensor time fraction is integrated for h times and divided by h to obtain the average crank position sensor time fraction by Equation 1 below.

[Equation 1]

Average crank position sensor time fraction (i) = ∑ crank position sensor time fraction (i) / h

Where i = 1 .... 12

The value thus obtained is stored in non-volatile memory, and the crank position sensor learning completion bit is turned on (step 127).

In step 127, the crank position sensor learning complete bit is reset every time.

As described above, after the condition of step 121 is established, the rising and falling time of each crank position sensor is measured from the rising edge of the longest tooth of the cam position sensor, and divided by the time taken for one rotation of the cam position sensor. Calculate the relative position of the crank position sensor edge.

This process is performed h times, the average value is stored in the nonvolatile memory, and the learning completion bit is turned on.

When the learning is completed and the crank position sensor temporary error code is on, the cam position is multiplied by the rotation time of the cam position sensor by the time fraction of each edge of the crank position sensor stored in the nonvolatile memory device. It calculates the time from the longest rising edge of the sensor to each edge of the crank position sensor and calculates the virtual crank position sensor.

By synchronizing such a virtual crank position sensor with a cam position sensor, cylinders are divided, the fuel amount is kept as normal, and the ignition timing is controlled by being perceived more than normal by α ° for safety.

However, if the learning is not completed, it is as if there is no reference point to control the engine, so the fuel cut is forcibly stalled.

Other crank position sensor error determinations and other controls are performed according to existing logic.

On the other hand, if the condition in step 130 is not satisfied, control is performed at the normal fuel control amount and the ignition timing, and the control is terminated (step 210).

In other words, if there is a change in the signal of the crank position sensor, the normal fuel amount and ignition timing control are performed because it is normal.

In step 140, if it is determined that the crank position sensor learning is not completed, a fuel cut is performed, and the control is terminated (step 220).

When explaining the basis of the configuration applied to the engine stall prevention method of the vehicle according to the present invention made as described above are as follows.

5 shows a normal signal diagram of a crank position sensor and a cam position sensor of a real vehicle.

As shown, the cam position sensor consists of one wide tooth and three teeth of the same size which are slightly narrower, and the crank position sensor has three equal teeth positioned at equal intervals.

The cylinder is synchronized (or recognized) by the combination of the cam position sensor high level or the low level to the rising edge and the falling edge timing of each tooth of the crank position sensor. In addition, the rising edge of each crank position sensor tooth corresponds to 5 ° BDC (TDC) and the falling edge corresponds to 75 ° BDC (TDC).

As shown in FIG. 5, cylinders synchronized according to the level of the cam position sensor with respect to the falling edge and the rising edge of the crank position sensor tooth are shown in Table 1 below.

TABLE 1

Crank position sensor Cam position sensor level at rising edge H L L H Crank position sensor Cam position sensor level at rising edge H H L L Judgment cylinder 2 3,6 4,1 5

In Table 1 above, the cylinder includes both four and six cylinders.

6, the crank position sensor rotates two times in one rotation of the cam position sensor. That is, six crank position sensor teeth pass in one rotation of the cam position sensor. Accordingly, the total number of crank position sensor edges is 12, including both rising and falling, based on the longest rising edge of the cam position sensor. If the 12 relative positions are known, there is no problem in distinguishing cylinders by setting the virtual crank position sensor even when the crank position sensor is polled.

In addition, by measuring the time between the rising edge of the longest tooth of the cam position sensor and the rising and falling edge of each tooth of the crank position sensor and dividing by the time taken for one rotation of the cam position sensor, the rising edge of the longest tooth of the cam position sensor The relative position (fraction) of the crank position sensor tooth from is calculated, which is constant regardless of engine RPM.

Therefore, when the signals of the crank position sensor and the cam position sensor are normal by using the same principle as described above, if a certain learning condition is established, the relative position of the crank position sensor tooth with respect to the cam position sensor is learned. The learning is averaged after learning a certain number of times to improve accuracy. Once this learning is complete, no further learning is done until the engine is turned off.

If you remember this learning value and the crank position sensor signal is abnormal, immediately turn on the temporary error code, enter the lymph-home condition, and learn the virtual crank position in the vehicle's ECU. The cylinder determination is continued based on the sensor tooth position, and the fuel amount and ignition timing are controlled as before.

At this time, the ignition timing is controlled by recognizing a certain value in the basic ignition timing map to protect the engine, and the error determination and the operation of the malfunction indication lamp MIL are performed as before.

When the crank position sensor outputs a normal signal, it immediately turns off the temporary error code and releases the lymph groove mode.

As described above, the engine stall prevention method of the vehicle according to the present invention has the following effects.

It is possible to prevent engine stalls caused by poor contact with the crank position sensor, which is currently unsatisfactory in the field, and improve driving stability. Also, an error of the crank position sensor can be detected normally, thereby making it easier to maintain the vehicle.

Although the present invention has been described with reference to one embodiment illustrated in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

Claims (5)

(a) determining whether the engine of the vehicle is in operation; (b) if it is determined in step (a) that the engine is running, performing crank position sensor learning; (c) determining that there is no change in crank position sensor signal between the cam position sensor rising edges; (d) determining whether crank position sensor learning is completed when the condition in step (c) is satisfied; (e) If it is determined in step (d) that the crank position sensor learning is completed, the crank position sensor time fraction is multiplied by the time taken for one rotation of the cam position sensor to calculate the virtual crank position sensor edge, and the calculated virtual Synchronizing a crank position sensor tooth with a cam position sensor to identify each cylinder; (g) controlling the amount of fuel in a normal manner, and controlling the ignition timing by a general angle of α °; and preventing the engine stall of the vehicle. The method of claim 1, In the step (b), performing the crank position sensor learning, (A) a second has elapsed since the engine started, (b <engine speed <c), (d <engine load <e), (cooling water temperature> f), (TPS change amount <g), and (crank position sensor) Determining whether the crank position sensor learning completion bit is off; (B) measuring the time from the measured rising edge of the cam position sensor to each falling and rising edge of the crank position sensor, and simultaneously measuring the time taken for one revolution of the cam position sensor; (C) dividing the measured time to each falling and rising edge of the crank position sensor by one crank position sensor rotation time; (D) calculate the average crank position sensor time fraction by integrating the calculated crank position sensor time fraction by h times, storing the obtained value in nonvolatile memory, and turning on the crank position sensor learning completion bit. Engine stall prevention method for a vehicle, characterized in that it comprises a. The method of claim 2, In the step (d), the crank position sensor learning completion bit is reset every time the engine stall prevention method of the vehicle. The method of claim 1, If the condition in step (c) is not satisfied, control is carried out at a normal fuel control amount and an ignition timing, and the control is terminated. The method of claim 1, In the step (d), if it is determined that the crank position sensor learning is completed in the step (d), the fuel cut prevention method of the vehicle, characterized in that to perform a fuel cut and end the present control.