KR100422668B1 - Method of controlling air on the map sensor trouble in a vehicle - Google Patents

Abstract

Disclosed is a method of controlling an amount of air when a map sensor of a vehicle fails. A method of controlling an air volume at a failure of a map sensor of a disclosed vehicle includes: (a) reading an HFM signal; (b) calculating an air quantity Qa; (c) calculating a maximum air quantity Qmax; (d) reading a signal from a map which is an intake pressure measuring sensor; (e) calculating the intake pressure P_int; (f) calculating atmospheric pressure P_atm; (g) reading a TPS signal; (h) determining whether the intake pressure P_int is greater than the atmospheric pressure P_atm; (i) determining whether the TPS is smaller than a threshold when the intake pressure P_int is greater than the atmospheric pressure P_atm in step (h); (j) if the condition in step (i) is met, determining whether the HFM is less than the threshold; (k) calculating a final air quantity Qf1 when the condition in step (j) is satisfied; (l) storing the error of the map sensor; (m) lighting the MIL; characterized in that it comprises a. According to the present invention, there is an advantage that can prevent the engine starting off phenomenon.

Description

How to control the air volume when the vehicle's map sensor breaks down {METHOD OF CONTROLLING AIR ON THE MAP SENSOR TROUBLE IN A VEHICLE}

The present invention relates to a method for controlling air volume when a map of a vehicle (MAP) Manifold Absolute Pressure (SMA) sensor fails. More specifically, the engine starting is prevented from being turned off, the engine operability is improved, and an accurate troubleshooting is made. The present invention relates to a method for controlling air volume when a map sensor of a vehicle fails.

EGR (Exhaust Gas Re-circulation) system is a device that recycles exhaust gas to the intake system for the purpose of lowering the combustion chamber temperature of the engine to reduce NOx emissions. If this EGR system fails, emissions will increase and must be monitored. This monitoring method takes advantage of the fact that the intake pressure changes at the moment the EGR enters. That is, in a normal EGR system, the intake pressure change occurs when the EGR valve is turned on / off.

However, there is no change in intake pressure in the failed EGR system. Therefore, a map sensor is mounted on the intake system to detect the change in intake pressure.

The MAP sensor is used to calculate atmospheric pressure and intake pressure as shown in FIG. 1, and is also used for HFM (Hot Film) signal compensation. The area where the HFM signal is distorted is when the intake pressure is close to atmospheric pressure, that is, a wide open throttle (WOT). At this time, the HFM signal appears rather small when the throttle opening degree is WOT. The above-mentioned HFM signal is not linearly proportional to the throttle opening amount but becomes smaller in the WOT. Map sensors are used to compensate for this.

In the prior art, HFM distortion compensation is designed using the above-described map sensor when the intake pressure is higher than atmospheric pressure. However, when the map sensor fails, for example, when the sensor is shorted to ground, the map sensor signal has a maximum value and a value greater than atmospheric pressure. At this time, HFM distortion compensation is performed to read a much larger air volume value than it actually is.

Figure 2 shows the results of testing the actual Sirius (Sirius) 2.4L engine why the HFM distortion compensation is necessary. Here, the X axis is the intake negative pressure (atmospheric pressure intake pressure), and the Y axis is the air amount value.

3 is a schematic flowchart sequentially illustrating a method of controlling an air volume when a map sensor of a vehicle breaks down according to the related art.

As shown, first, the HFM signal is read (step 10). That is, the voltage is read from the HFM which is an air mass measurement sensor. Subsequently, the air amount Qa is calculated. (Step 20) The above-described HFM sensor generates a voltage linearly according to the air amount. Therefore, reading the HFM voltage converts it to air volume.

The maximum air amount Qmax is calculated (step 30). Qmax is calculated to prevent output loss due to distortion of the HFM signal. At this time, Qmax = Qa × compensation factor (Factor) Here, the compensation factor is corrected according to the intake air temperature, cooling water temperature, atmospheric pressure.

It also reads the MAP signal (step 40). It reads the voltage from the map which is the intake pressure measuring sensor.

Next, the intake pressure P_int is calculated (step 50). The map sensor generates a voltage linearly with the pressure. Therefore, reading the map voltage converts it to intake pressure.

The atmospheric pressure P_atm is calculated (step 60). At this time, the atmospheric pressure is calculated using the map sensor signal. In addition, the difference between the intake air pressure and the atmospheric pressure is determined.

In step 70, if the intake pressure is greater than atmospheric pressure (P_int> P_atm), the final air amount Qf is calculated and the flow (logic) ends (step 80, 90). At this time, Qf = Qmax (maximum intake air amount limit value). And Qf = Qa.

However, since the air amount Qa value is changed to the maximum air amount Qmax, the fuel amount increases accordingly. The amount of air actually entering the engine remains unchanged, but a failure of the map sensor results in a change in the calculated amount of air. Therefore, the combustion state becomes very rich. This causes the engine to turn off.

As shown in Fig. 4, the map signal is fixed at 4.5V at the same time as the sensor ground open, at which time according to the sensor (AFS) signal distortion countermeasure logic to the air pull during WOT when calculating the intake air volume in the ECU. Since Qa = Qmax, the ECU determination filling efficiency Ec increases rapidly, whereby the fuel amount becomes too rich and the engine is turned off.

In addition, the vehicle may not be driven due to the start-off phenomenon as described above, and thus it is impossible to diagnose a failure of the map sensor. Therefore, EGR monitoring cannot be performed because the EGR monitoring condition cannot be entered.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides an air volume control method in case of failure of a map sensor of a vehicle to prevent an engine starting off phenomenon by preventing abnormal calculation of air volume when a map sensor fails. There is this.

1 is a schematic system configuration diagram to which the air volume control method is applied when a map sensor failure of a vehicle according to the prior art is applied.

Figure 2 is a graph showing the results of testing the actual Sirius 2.4L engine why the HFM distortion compensation is necessary.

3 is a schematic flowchart sequentially illustrating a method of controlling an amount of air during a failure of a map sensor of a vehicle according to the related art.

4 is a graph appearing when the actual engine start-off phenomenon occurs.

5 is a schematic flowchart sequentially illustrating a method for controlling air volume when a map sensor failure of a vehicle according to the present invention is performed.

6 is a schematic system configuration to which the air amount control method is applied when a map sensor failure of a vehicle according to the present invention is applied.

In order to achieve the above object, there is provided a method of controlling an amount of air during a failure of a map sensor of a vehicle of the present invention, the method comprising: (a) reading an HFM signal; (b) calculating an air quantity Qa; (c) calculating a maximum air quantity Qmax; (d) reading a signal from a map which is an intake pressure measuring sensor; (e) calculating the intake pressure P_int; (f) calculating atmospheric pressure P_atm; (g) reading a TPS signal; (h) determining whether the intake pressure P_int is greater than the atmospheric pressure P_atm; (i) determining whether the TPS is smaller than a threshold when the intake pressure P_int is greater than the atmospheric pressure P_atm in step (h); (j) if the condition in step (i) is met, determining whether the HFM is less than the threshold; (k) calculating a final air quantity Qf1 when the condition in step (j) is satisfied; (l) storing the error of the map sensor; (m) lighting the MIL; characterized in that it comprises a.

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

FIG. 5 is a schematic flowchart sequentially illustrating a method of controlling an air volume when a map sensor failure of a vehicle according to the present invention is performed, and FIG. 6 is a configuration of a system to which the method of controlling air volume when a map sensor failure of a vehicle according to the present invention is applied. Figure is schematically shown.

Referring to each of the drawings, the method for controlling the air volume at the time of failure of the map sensor of the vehicle according to the present invention first reads the HFM signal.

Then, the air amount Qa is calculated (step 120). The HFM sensor generates a voltage linearly according to the air amount. Therefore, reading the HFM voltage converts it to the air volume Qa.

The maximum air amount Qmax is then calculated. (Step 130) The maximum air amount Qmax is calculated to prevent an output loss caused by the HFM signal distortion. In step 130, the maximum air amount Qmax is calculated by Equation 1 below.

Qmax = Qa x Compensation factor 1 x Compensation factor 2

Here, the compensation factor 1 is a value corrected according to the intake air temperature, cooling water temperature, atmospheric pressure,

Compensation factor 2 is a value corrected according to the TPS.

In addition, the signal is read from the map that is the intake pressure measurement sensor (step 140). That is, the voltage is read from the map that is the intake pressure measurement sensor.

Next, the intake pressure P_int is calculated. (Step 150) Since the map sensor generates a voltage linearly according to the pressure, reading the map voltage converts it to the intake pressure P_int.

The atmospheric pressure P_atm is also calculated (step 160).

Then, the TPS signal is read (step 170). When the TPS opening degree is higher than or equal to a predetermined value, the intake pressure P_int is replaced with the atmospheric pressure P_atm value.

Next, it is determined whether the intake pressure P_int is greater than the atmospheric pressure P_atm (step 180).

If the intake pressure P_int is greater than the atmospheric pressure P_atm in step 180, it is determined whether the TPS is smaller than a threshold.

If the condition in step 190 is satisfied, it is determined whether the HFM is smaller than a threshold (step 200).

The TPS opening degree and the HFM signal are determined in the above, and when the map signal is greater than atmospheric pressure at a TPS opening degree or less, it is determined as a failure, and when the map signal is greater than atmospheric pressure when the HFM signal is below a certain value, it is determined as a failure. .

If the condition in step 200 is satisfied, the final air quantity Qf1 is calculated.

In addition, an error of the map sensor is stored (step 220).

Also, the MIL (Malfunction Indicator Light) is turned on (step 230).

On the other hand, if the condition in step 190 is not satisfied, the final air amount Qf is calculated (step 240).

The final air volume Qf2 is calculated (step 250).

When the intake pressure P_int is larger than the atmospheric pressure P_atm, Qf = Qmax (maximum air amount). Qf = Qa when the map sensor judges a failure.

On the other hand, if the condition in step 180 or 200 is not satisfied, step 250 is performed.

The method of controlling the air volume at the time of the failure of the map sensor of the vehicle according to the present invention having the above-described configuration strengthens the map sensor failure determination condition so that the engine can be normally operated by stopping HFM signal compensation immediately after the failure. Also, map sensor diagnosis can be performed more accurately to give reliability to other monitoring items (eg, EGR).

In the present invention, the HFM distortion compensation is designed only when the intake pressure P_int is greater than the atmospheric pressure P_atm when the map sensor is normal. Therefore, when the map sensor fails, for example, when the sensor is shorted to ground, the HFM distortion compensation is not performed even if the map sensor signal has a maximum value and a value larger than the atmospheric pressure P_atm.

As described above, the air volume control method in case of failure of the map sensor of the vehicle according to the present invention has the following effects.

By preventing abnormal air volume calculations in the event of a map sensor failure, air volume and fuel volume matching can be made properly. Therefore, the engine starting off phenomenon can be prevented.

The refinement of the map sensor diagnostics enables the operation and OBD-2 monitoring diagnostics, the prevention of start off, the map sensor diagnostics, and other OBD-2 monitoring functions.

Although the present invention has been described with reference to one embodiment shown 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 (4)

(a) reading the HFM signal; (b) calculating an air quantity Qa; (c) calculating a maximum air quantity Qmax; (d) reading a signal from a map which is an intake pressure measuring sensor; (e) calculating the intake pressure P_int; (f) calculating atmospheric pressure P_atm; (g) reading a TPS signal; (h) determining whether the intake pressure P_int is greater than the atmospheric pressure P_atm; (i) determining whether the TPS is smaller than a threshold when the intake pressure P_int is greater than the atmospheric pressure P_atm in step (h); (j) if the condition in step (i) is satisfied, determining whether the HFM is less than the threshold; (k) calculating a final air quantity Qf1 when the condition in step (j) is satisfied; (l) storing the error of the map sensor; (m) lighting the MIL; air volume control method when the map sensor failure of the vehicle, comprising a. The method of claim 1, In the step (c), the maximum air amount (Qmax) is calculated by the following equation, the vehicle air volume control method of the failure of the map sensor of the vehicle. [Equation 1] Qmax = Qa x Compensation factor 1 x Compensation factor 2 Here, the compensation factor 1 is a value corrected according to the intake air temperature, cooling water temperature, atmospheric pressure, Compensation factor 2 is a value corrected according to the TPS. The method of claim 1, (n) calculating a final air quantity Qf if the condition in step (i) is not satisfied; (o) calculating a final air quantity (Qf2); air volume control method when the map sensor failure of the vehicle, characterized in that it further comprises. The method of claim 3, If the condition in step (h) or (j) is not satisfied, step (o) is to perform the air volume control method of the failure of the map sensor of the vehicle.