KR20020018749A - Method for filtering air flow sensor noise of vehicle - Google Patents

Abstract

PURPOSE: A noise filtering method of a suction air amount sensor for a vehicle is provided to minimize influence of signal noise on the actual fuel amount in contact failure of the suction air amount sensor by filtering signals from the suction air amount sensor according to changes of throttle opening degree. CONSTITUTION: Starting an engine is detected at the initial stage(200), and the filtering coefficient is set as one against the measured suction air amount in starting the engine(210). Fuel shutoff and trailing condition is detected in not starting the engine(220), and the filtering coefficient is established with map value according to rpm of the engine under fuel shutoff and trailing condition(230). The filtering coefficient is set with the map value according the rpm of the engine and the basic air amount in not satisfying the fuel shutoff and trailing condition(240). The suction air amount is filtered with determined filtering coefficients, and the fuel amount is calculated with the filtered suction air amount(250). The stall of the engine is prevented with filtering signal noise at contact failure of a connector or wiring.

Description

Intake air volume sensor noise filtering method of vehicle {METHOD FOR FILTERING AIR FLOW SENSOR NOISE OF VEHICLE}

The present invention relates to a method of filtering noise of an intake air amount sensor of a vehicle, and more particularly, a signal noise generated when a contact failure of the intake air amount sensor is affected by filtering the signal of the intake air amount sensor according to a change in throttle opening degree. It relates to a method of filtering noise of an intake air amount sensor of a vehicle so as to be minimized.

Conventional intake air volume sensor noise filtering method is applied to remove the noise by simply filtering the signal of the intake air volume sensor itself, and uses a variety of software filtering method for each electronic control device, but all the above filtering methods It falls within the scope of simplified primary digital filtering.

In addition, it may be said that the filtering is intended to increase or decrease the filtering using different filtering constants according to the engine operating conditions.

However, if the intake air amount sensor is intermittent or long-term due to a poor contact occurring in a connector, a pin, or a wiring of the connector, a sensor signal drop occurs, and in this case, the sensor signal can compensate for this by the first digital filtering. It becomes impossible.

Therefore, the engine speed drop occurs because the fuel amount or air amount control is calculated by the noise caused by the contact failure, and the engine stall occurs when the engine speed drop is severe.

Nevertheless, the conventional filtering method has a limitation in that it is not possible to determine a failure or to perform proper filtering for the occurrence of noise due to the contact failure.

In other words, if the filtering of the measurement signal of the intake air quantity sensor is large, the noise can be basically reduced, but in this case, the intake air quantity signal does not reflect the actual air volume during acceleration and deceleration, causing excessive thinning or over-concentration to increase the exhaust gas. Of course, there is a problem that worsens the driving.

Accordingly, an object of the present invention is to filter the intake air amount by reducing the filtering coefficient when the amount of variation in the throttle opening degree is small with respect to the measurement signal of the intake air amount sensor, and filtering the intake air amount by increasing the filtering coefficient when the variation in the throttle opening degree is large. After the fuel amount is calculated by the filtered intake air amount, the signal noise generated when a poor contact of the intake air amount sensor is to minimize the influence of the fuel amount.

1 is a block diagram of the intake air amount sensor noise filtering control applied to the present invention.

2 is a flowchart of the intake air amount sensor noise filtering method of the present invention.

In order to realize the above object, the present invention includes the steps of filtering the throttle opening degree change amount according to the engine speed, the basic air amount from the throttle position sensor with respect to the air amount measured from the intake air amount sensor; Calculating a filtering coefficient large and small according to the throttle opening degree variation filtered in the step; Filtering by applying the filtering coefficient calculated in the step to the actual amount of intake air; Comprising the step of calculating the fuel amount while increasing and decreasing the fuel amount to the filtered intake air amount in the step.

Therefore, according to the present invention, by allowing the intake air amount sensor to filter the noise of the signal caused by the poor contact of the connector or the wiring, it is possible to prevent the engine stall due to the decrease in the engine speed caused by the noise. It will be possible.

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

1 is a block diagram of an intake air amount sensor noise filtering control applied to the present invention, and includes a sensor resistor film Rs, a temperature sensor bridge trimming resistor Rh, a heater resistor R1 R2, and an amplifier circuit AMP. One hot film element is formed by integrating a layer resistor on a ceramic substrate to output an output voltage, that is, an intake air amount proportional to the size of the intake air amount, from the engine control unit ECU, and the engine control unit ECU inputs the output voltage. The combustion amount is determined based on the intake air amount and the throttle opening amount to control the actuator.

2 is a flowchart of the method for filtering the intake air amount sensor noise of the present invention, comprising: determining whether the engine is being started in an initial state; Setting the filtering coefficient to 1 for the measured amount of intake air if the engine is being started in step 200; Determining that the fuel cutoff and the trailing condition are applied when the engine is not started at step 200; Setting the filtering coefficient to a map value according to the engine speed when the fuel cutoff and the trailing condition are performed in the step 220; Setting the filtering coefficient to a map value according to the engine speed and the basic air quantity measurement value (240) if the fuel blocking and trailing conditions are not the step (230); In step 210, 230, and 260, the intake air amount is filtered using the filtering coefficients set respectively, and the amount of fuel is calculated using the filtered intake air amount 250.

The setting of the filtering coefficient in a state other than the fuel cutoff and the trailing condition (240) includes calculating (241) a change amount of the throttle opening degree at an interval of an hourly constant (X1) according to the engine speed and the current air volume; Determining (242) whether the change amount of the throttle opening degree is greater than or equal to the throttle opening limit in step (241); Calculating (243) the fuel amount with a very high filtering coefficient if the amount of change in the throttle opening degree is not greater than or equal to the throttle opening degree threshold in step (242); Detecting (244) an acceleration / deceleration condition if the amount of change in the throttle opening degree is greater than or equal to the throttle opening degree threshold in the step (242); Determining (245) whether the amount of change in the next throttle opening degree is greater than or equal to the throttle opening limit after detecting the acceleration / deceleration condition in the step (244); Setting the filtering coefficient to a very low constant according to the throttle opening degree variation amount if the variation of the next throttle opening degree value is greater than or equal to the throttle opening degree threshold value in step 245; In the step 245, if the amount of change in the next throttle opening degree is not greater than or equal to the throttle opening degree limit, the filtering coefficient is set to a low constant according to the amount of change in the throttle opening degree.

According to the present invention as described above, it is determined whether the engine is being started in the vehicle (step 200). If the engine is being started at this time, the engine control unit ECU determines the filtering coefficient with respect to the air amount measured from the intake air amount sensor AFS. (Ck) is set to 1 (step 210).

The engine control unit ECU then filters the intake air amount MAF with the set filtering coefficient Ck = 1, where intake air amount filtering MAF = intake air amount MAF (n-1) + filtering coefficient Ck. [Base air mass measurement (MAF_MES)-filter by intake air quantity MAF (n-1) and calculate the fuel quantity by this filtered intake air quantity MAF (step 250).

If the engine is not started at step 200, the engine control unit ECU determines whether the engine is a fuel cutoff and a trailing condition (step 220).

At this time, if the fuel cut-off and trailing conditions, the filtering coefficient Ck = Ck (Ne) is set to a map value according to the engine speed Ne for the air amount measured by the intake air amount sensor AFS (step 230).

Subsequently, the engine control unit ECU filters the intake air amount MAF by the filtering coefficient Ck by the map value according to the set engine speed Ne, wherein the filtered intake air amount MAF = the intake air amount MAF (n -1) Filtering by + Filtering Coefficient (Ck) · [Basic Air Volume Measurement (MAF_MES)-Intake Air Volume (MAF (n-1))] and the fuel quantity is calculated from this filtered Intake Air Volume (MAF) (step 250). .

On the other hand, the engine control unit ECU sets the filtering coefficient to a map value according to the engine speed and the basic air quantity measurement value, in step 230, if it is not a fuel cutoff and trailing condition (step 240).

That is, in the non-fuel cutoff and trailing condition, the filtering coefficient setting calculates the variation amount ΔTPS of the throttle opening at an interval of constant time X1 (step 241), and the time constant X1 is an engine displacement and a surge. It is a delay from the opening of the throttle valve to the intake manifold sensor signal based on the tank capacity, calculated by the cylinder charging mode, and constant according to the engine speed Ne and the current air volume MAF (step 241). ).

Subsequently, the engine controller ECU determines whether the calculated change amount ΔTPS of the throttle opening degree is equal to or greater than the throttle opening degree limit value TPSthd1 (step 242), and the change amount ΔTPS of the throttle opening amount is the throttle opening degree. If not higher than the threshold value TPSthd1, the engine controller ECU sets a very high filtering coefficient Ck, which is a filtering coefficient Ck for the engine speed Ne and the basic air mass measurement value MAF_MES. (Step 243), after setting the set high filtering coefficient (Ck) to filter the intake air amount by the set filtering coefficient, where the intake air amount filtering (MAF) = intake air amount (MAF (n-1) + filtering coefficient) (Ck) · [Basic air mass measurement value MAF_MES—intake air volume MAF (n-1)], and the fuel amount is calculated from this filtered intake air volume (step 250).

If the change amount ΔTPS of the throttle opening degree is greater than or equal to the throttle opening limit value TPSthd1 in the step 242, the engine control unit ECU detects the acceleration / deceleration condition (step 244), and then detects the acceleration / deceleration condition. Accordingly, it is determined whether the change amount ΔTPS (n-1) of the next throttle opening degree is greater than or equal to the throttle opening limit value TPSthd1 (step 245), and the determination result shows that the change amount ΔTPS (n-1) of the next throttle opening amount is the throttle opening amount. If the threshold value TPSthd1 or more, the engine control unit ECU sets the filtering coefficient Ck to a very low filtering coefficient as a change amount ΔTPS of the throttle opening for one hour (step 246), and then sets the very low filtering. The intake air amount is filtered by the coefficient Ck. The intake air amount filtering MAF = the intake air amount MAF (n-1) + the filtering coefficient Ck. [Basic air amount measurement value (MAF_MES)-the intake air amount (MAF ( n-1)] and this filtered It will calculate the amount of fuel in the mouth air amount (step 250).

On the other hand, if the change amount ΔTPS (n-1) of the next throttle opening degree is not greater than or equal to the throttle opening limit value TPSthd1 in the step 245, the engine control unit ECU sets the filtering coefficient Ck for 2 hours. By setting the low filtering coefficient to the variation amount ΔTPS (step 247), the intake air amount is filtered by the set low filtering coefficient Ck, where the intake air amount filtering (MAF) = the intake air amount (MAF (n-1) + filtering). The filter is calculated by the coefficient Ck · [base air amount measurement value MAF_MES—intake air amount MAF (n-1)] and the fuel amount is calculated using the filtered intake air amount (step 250).

As described above, the present invention calculates the filtering coefficient for the throttle opening degree variation filtered from the throttle position sensor by the engine speed and the basic air quantity measurement value from the air quantity signal measured by the intake air quantity sensor according to the calculated filtering coefficient. By filtering the amount of air while increasing or decreasing the amount of air, and calculating the amount of fuel while increasing and decreasing the actual amount of air with this filtered intake air, the intake air volume sensor filters for noise in signals generated by poor contact of connectors or wiring. This is to provide an effect that can prevent the engine stall due to the drop in the engine speed caused by the noise.

Claims (4)

Determining whether the engine is being started in the initialization state; Setting the filtering coefficient to 1 for the measured intake air amount when the engine is starting in the step; If it is not during the engine starting in the step, determining whether the fuel cut and trailing conditions; Setting the filtering coefficient to a map value according to the engine speed when the fuel cut and trailing conditions are performed in the step; Setting the filtering coefficient to a map value according to the engine speed and the basic air quantity measurement value, unless the fuel cutoff and trailing conditions are used in the step; And filtering the intake air amount by the filtering coefficient set in the step, and calculating the fuel amount by the filtered intake air amount. 2. The method of claim 1, wherein the setting of the filtering coefficients in a state other than the fuel cutoff and the trailing condition comprises: calculating a change amount of the throttle opening degree at an interval of an hourly constant (X1) according to the engine speed and the current air volume; Determining whether the amount of change in the throttle opening degree is greater than or equal to the throttle opening limit in the step; If the amount of change in the throttle opening degree is not greater than or equal to the throttle opening limit, it is set to a very high filtering coefficient to filter the intake air amount with this set filtering coefficient, and the fuel amount is calculated using the filtered intake air amount. Intake air volume sensor noise filtering method of vehicle. The method of claim 2, further comprising: detecting an acceleration / deceleration condition if the amount of change in the throttle opening degree is greater than or equal to the throttle opening degree limit in the step of determining whether the amount of change in the throttle opening degree is greater than or equal to the throttle opening degree; Determining whether the amount of change in the next throttle opening degree is greater than or equal to the throttle opening degree limit value after detecting the acceleration / deceleration condition in the step; In the above step, if the change amount of the next throttle opening amount is greater than or equal to the throttle opening limit value, the filtering coefficient is set to a very low constant according to the throttle opening change amount, the intake air amount is filtered by the set filtering coefficient, and the fuel amount is calculated using the filtered intake air amount. Noise filtering method of the intake air amount sensor of a vehicle, characterized in that consisting of. 4. The method of claim 3, wherein in the determining whether the change amount of the next throttle opening amount is greater than or equal to the throttle opening limit value, the filtering coefficient is set to a low constant according to the change amount of the throttle opening amount if the change amount of the next throttle opening amount is not more than the throttle opening limit value. And filtering the intake air amount with the set filtering coefficient and calculating the fuel amount with the filtered intake air amount.