KR102064750B1 - Apparatus and method for diagnosing failure of air pressure sensor in vehicle - Google Patents

Abstract

The present invention relates to an apparatus for diagnosing the failure of an air pressure sensor in a vehicle, including: the air pressure sensor for detecting the air pressure of an intake manifold in the vehicle; an engine rpm detecting unit detecting information on vehicle engine rpm; a throttle valve opening amount detecting unit detecting the throttle valve opening amount of the vehicle; and a control unit determining whether the air pressure sensor or the throttle valve has failed by using a predetermined pressure drop amount threshold of the air pressure sensor according to a throttle valve opening amount and engine rpm.

Description

Fault diagnosis apparatus and method of vehicle air pressure sensor {APPARATUS AND METHOD FOR DIAGNOSING FAILURE OF AIR PRESSURE SENSOR IN VEHICLE}

The present invention relates to an apparatus and method for diagnosing a failure of a vehicle air pressure sensor, and more particularly, to diagnose a failure of an air pressure sensor mounted on an intake manifold for controlling the output of an engine in a vehicle. An apparatus and method for diagnosing a failure of a vehicle air pressure sensor may be used to diagnose a failure of the air pressure sensor by using a pressure drop amount threshold of the air pressure sensor predetermined according to an engine speed.

In general, a vehicle uses an air pressure sensor mounted on an intake manifold to control the engine output and calculates the air volume based on the fuel pressure. Therefore, if the air amount calculation is incorrect due to the air pressure sensor failure, abnormal control of the fuel amount is performed. As a result, there is a problem that leads to an abnormal output of the engine and an increase in pollutant emissions due to the failure of the air pressure sensor.

For example, a mass air flow (MAF) sensor or a manifold air pressure (MAP) sensor (hereinafter, referred to as an air pressure sensor) is used to measure the amount of intake air flowing into the engine for calculating fuel injection amount in a vehicle.

The MAF sensor directly measures the amount of air passing through the throttle valve and provides the information to the engine control means, while the MAP sensor measures the pressure and air temperature of the intake manifold (or intake manifold) and then measures the amount of air. By converting the information into intake air amount information to the engine control means (not shown).

Therefore, when the MAP sensor (air pressure sensor) is used in the vehicle, the failure of this air pressure sensor becomes impossible to measure the current intake air amount by the engine control means, and at the same time, it deteriorates the driving performance of the vehicle, such as startability and acceleration. As the air-fuel ratio cannot be controlled, there is a problem in that excessive exhaust gas is emitted. Therefore, fault diagnosis of MAP sensor in the vehicle plays a very important role.

For reference, in order to diagnose the failure of the air pressure sensor, the fault may be diagnosed using the upper / lower limit value of the output voltage of the air pressure sensor, or the output value (ie, the pressure value) and the throttle valve position of the air pressure sensor may be used. A method of diagnosing a failure of the air pressure sensor by comparing air pressure values calculated using a sensor (not shown) is used.

However, in case of using the upper / lower limit value of the output voltage of the air pressure sensor, if the output voltage is stuck within the upper / lower limit value of the output voltage of the air pressure sensor or exhibits abnormal behavior, There is a problem that can not diagnose the failure.

In addition, when the throttle valve position sensor is used for diagnosing a failure of the air pressure sensor as described above, even when an error occurs in the throttle valve position sensor, there is a problem that the air pressure sensor may be incorrectly determined as a failure. . Therefore, there is a need for a method for more stably diagnosing a failure of the air pressure sensor.

Background art of the present invention is disclosed in Republic of Korea Patent Registration No. 10-0490890 (2005.05.12. Registration, error detection device of manifold pressure and intake temperature integrated sensor).

According to an aspect of the present invention, the present invention was created to solve the above problems, in order to diagnose the failure of the air pressure sensor mounted on the intake manifold to control the output of the engine in the vehicle, the throttle valve is opened Provided is an apparatus and method for diagnosing a failure of a vehicle air pressure sensor, by which a failure of the air pressure sensor can be diagnosed by using a predetermined pressure drop threshold of the air pressure sensor according to a quantity and an engine speed. Its purpose is to.

An apparatus for diagnosing a failure of a vehicle air pressure sensor according to an aspect of the present invention includes an air pressure sensor detecting an air pressure of an intake manifold of a vehicle; An engine rotation speed detection unit detecting rotation speed information of the vehicle engine; A throttle valve opening amount detecting unit detecting a throttle valve opening amount of the vehicle; And a controller configured to determine whether the air pressure sensor or the throttle valve has failed by using a pressure drop amount threshold of a predetermined air pressure sensor according to the throttle valve opening amount and the engine speed.

In the present invention, a lambda sensor for detecting the oxygen concentration in the exhaust gas of the vehicle; further comprising, the control unit, if it is determined that the failure state of the air pressure sensor or the throttle valve, the lambda sensor feedback value and the target lambda value It is characterized in that for detecting the lambda error, if the lambda error is smaller than the specified error threshold value is determined as the abnormality of the throttle valve.

In the present invention, the control unit determines that the lambda error is not an air pressure sensor when it is not smaller than a specified error threshold value.

In the present invention, in order to determine the failure state of the air pressure sensor or the throttle valve, the controller stores in advance the target lambda value of the lambda sensor according to the throttle valve opening amount and the engine speed.

In the present invention, on the basis of the determination result of the control unit, the diagnostic information output unit for guiding the means that the abnormality or failure has occurred or the normal state; characterized in that it further comprises.

In the present invention, in order to determine whether the air pressure sensor or the throttle valve failure, the pressure drop amount threshold value for storing the pressure drop amount threshold value predetermined according to the throttle valve opening amount and the engine speed And a storage unit.

In the present invention, the pressure drop amount threshold value includes an experimental value in a state where there is no failure in the air pressure sensor, the injector, the ignition coil, and the misfire means of the vehicle.

According to another aspect of the present invention, a method of diagnosing a failure of a vehicle air pressure sensor may include: checking, by a controller, an opening of an intake valve; Detecting, by the control unit, a pressure drop of the intake manifold by the air pressure sensor unit when the intake valve is opened; Drawing, by the control unit, a pressure drop amount threshold value of an air pressure sensor corresponding to the detected pressure drop amount, the throttle valve opening amount, and the engine speed in a designated table; And when the detected pressure drop amount is less than or equal to the drawn pressure drop amount threshold, the control unit determines that the air pressure sensor is in a normal state.

In the present invention, as a result of the comparison, if the detected pressure drop amount is greater than the drawn pressure drop amount threshold value, the control unit determines that there is an error in any one of the air pressure sensor or the throttle valve; It is characterized by including.

In the present invention, the control unit detects the feedback value of the lambda sensor according to the throttle valve opening amount and the engine speed, and the lambda error of the target lambda value set in advance corresponding to the throttle valve opening amount in order to determine the means by which the abnormality occurred. If the lambda error is smaller than a preset threshold, the controller determines that there is an error in the throttle valve.

In the present invention, if the lambda error is greater than or equal to a predetermined threshold value, the controller determines that there is an error in the air pressure sensor.

In the present invention, the target lambda value predetermined according to the throttle valve opening amount and the engine speed is stored in a table form in advance.

In the present invention, the control unit, if the intake valve is opened in order to determine whether the air pressure sensor or the throttle valve is broken, using the characteristic that the pressure in the intake manifold drops by the air sucked into the cylinder It features.

In the present invention, the control unit, when the intake valve is open, detects the opening amount and engine speed of the throttle valve, and the pressure drop amount threshold previously stored corresponding to the detected opening amount and engine speed of the throttle valve It is characterized by withdrawing a value.

In the present invention, the pressure drop amount threshold value of the air pressure sensor predetermined according to the throttle valve opening amount and the engine speed is stored in advance in the form of a table.

According to an aspect of the present invention, the present invention is to diagnose the failure of the air pressure sensor mounted on the intake manifold for the output control of the engine in the vehicle, the air pressure predetermined according to the throttle valve opening amount and the engine speed The pressure drop threshold of the sensor may be used to diagnose a failure of the air pressure sensor.

1 is an exemplary view showing a schematic configuration of a failure diagnosis apparatus for a vehicle air pressure sensor according to an embodiment of the present invention.
2 is a flowchart illustrating a failure diagnosis method of a vehicle air pressure sensor according to an exemplary embodiment of the present invention.
3 is an exemplary view showing a table storing a pressure drop amount threshold value of the air pressure sensor predetermined according to the throttle valve opening amount and the engine speed in FIG. 2.
4 is an exemplary view showing a table storing a target lambda value of a lambda sensor according to the throttle valve opening amount and the engine speed in FIG. 2.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of a failure diagnosis apparatus and method of a vehicle air pressure sensor according to the present invention.

In this process, the thickness of the lines or the size of the components shown in the drawings may be exaggerated for clarity and convenience of description. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or convention of a user or an operator. Therefore, definitions of these terms should be made based on the contents throughout the specification.

1 is an exemplary view showing a schematic configuration of a failure diagnosis apparatus for a vehicle air pressure sensor according to an embodiment of the present invention.

As shown in FIG. 1, the apparatus for diagnosing a failure of the vehicle air pressure sensor according to the present embodiment includes an air pressure sensor 101, an engine speed detector 102, a throttle valve opening amount detector 103, and a lambda sensor. The unit 104 includes a control unit 105, a pressure drop threshold storage unit 106, and a diagnostic information output unit 107.

The air pressure sensor 101 (or the air pressure sensor) measures the pressure and the air temperature of the intake manifold, converts it into an air amount, and outputs intake air amount information to the controller 105.

The engine speed detector 102 communicates with an engine controller (not shown) (or ECU) to detect engine speed information and output the engine speed information to the controller 105.

The throttle valve opening amount detection unit 103 detects the throttle valve opening amount using a sensor (or throttle position sensor) that detects an opening angle of the throttle valve and outputs the throttle valve opening amount to the controller 105.

The lambda sensor 104 (or lambda sensor) detects the oxygen concentration in the exhaust gas of the vehicle and measures the measured value (for example, a lambda value or a lambda feedback value) by using a sensor for measuring an air-fuel ratio to the controller 105. Output

The pressure drop threshold storage unit 106 stores a predetermined threshold (ie, pressure drop threshold) according to the throttle valve opening amount and the engine speed. The pressure drop threshold may include an experimental value at a steady state (ie, a steady state of an air pressure sensor).

In addition, although not specifically illustrated in the drawing, the target lambda value of the lambda sensor according to the throttle valve opening amount and the engine speed may be stored in advance in a memory (not shown).

The control unit 105 diagnoses a failure of the air pressure sensor by using a pressure drop threshold of the air pressure sensor predetermined according to a throttle valve opening amount and an engine speed, and includes a lambda sensor feedback value and a target. If an error of a lambda value is detected and the lambda error is smaller than a specified threshold (i.e., an error threshold), it is determined to be an abnormality of the throttle valve. If not, it is determined that the air pressure sensor is abnormal.

The diagnostic information output unit 107 guides a means (eg, a throttle valve or an air pressure sensor) in which an abnormality (or failure) occurs based on the determination result of the control unit 105 or notifies the user of the normal state.

Therefore, there is a need for a method for stably diagnosing a failure of the air pressure sensor without being affected by the throttle valve position sensor.

Hereinafter, the operation of the controller 105 will be described with reference to FIGS. 2 to 4.

2 is a flowchart illustrating a failure diagnosis method of a vehicle air pressure sensor according to an exemplary embodiment of the present invention, and FIG. 3 is the air pressure predetermined according to the throttle valve opening amount and the engine speed in FIG. 2. 4 is an exemplary diagram showing a table storing a pressure drop amount threshold of a sensor, and FIG. 4 is an exemplary diagram showing a table storing a target lambda value of a lambda sensor according to the throttle valve opening amount and the engine speed in FIG. 2. It is also.

Referring to FIG. 2, the controller 105 checks whether the intake valve is open (S101).

For reference, when the intake valve is opened, the pressure in the intake manifold is dropped because air is sucked into the cylinder. This characteristic is evident as the size of the intake manifold is small and the number of cylinders is small.

Accordingly, when the intake valve is opened (YES in S101), the control unit 105 detects the pressure drop amount by the air pressure sensor unit 101 (that is, the air pressure sensor) (S105).

In addition, when the intake valve is opened (YES in S101), the controller 105 detects the opening amount of the throttle valve (S102), and also detects the engine speed RPM (S103).

For example, the controller 105 communicates with an engine controller (not shown) (or ECU) through the engine speed detector 102 to detect engine speed information. In addition, the control unit 105 detects the throttle valve opening amount using a sensor for detecting the opening angle of the throttle valve through the throttle valve opening amount detection unit 103.

In addition, the control unit 105 refers to a table storing the pressure drop amount threshold value of the air pressure sensor predetermined according to the throttle valve opening amount and the engine speed (see FIG. 3), and the throttle valve opening amount and the engine rotation. The pressure drop amount threshold value of the air pressure sensor predetermined according to the number is withdrawn (S104).

Next, the controller 105 compares the pressure drop amount threshold drawn out in step S104 with the pressure drop amount detected in step S105 (S106).

As a result of the comparison through step S106, when the detected pressure drop amount is equal to or less than the drawn pressure drop amount threshold value (YES in S107), the controller 105 determines that the air pressure sensor is in a normal state (S108). .

On the other hand, as a result of the comparison through the step S106, when the detected pressure drop amount is larger than the drawn pressure drop amount threshold value (NO in S107), the controller 105 is abnormal to any one of the air pressure sensor or the throttle valve. It is determined that there is a (failure) (S109).

For reference, the pressure drop in the intake manifold depends on the throttle valve opening and engine speed. Therefore, in the present embodiment, the air pressure sensor can be diagnosed by comparing the pressure drop amount with a predetermined pressure drop amount threshold value according to the throttle valve opening amount and the engine speed.

In order to determine a means (e.g., an air pressure sensor or a throttle valve) in which the abnormality has occurred, the controller 105 determines the lambda value of the lambda sensor according to the lambda value (ie, the throttle valve opening amount and the engine speed). The error between the feedback value and the target lambda value (that is, the target lambda value of the lambda sensor according to the throttle valve opening amount and the engine speed) corresponding to the feedback value is detected (S110).

That is, the control unit 105 stores a table that stores a predetermined target lambda value (that is, a target lambda value of the lambda sensor according to the throttle valve opening amount and the engine speed) according to the throttle valve opening amount and the engine speed (FIG. 4). The error between the feedback value of the lambda sensor and the target lambda value is detected.

And when the lambda error (ie, the error between the feedback value of the lambda sensor and the target lambda value) is within a preset threshold (reference value) range (i.e., the lambda error is smaller than the preset threshold) (example of S111). The controller 105 determines that there is an abnormality in the throttle valve (S112), and the lambda error (that is, the error between the feedback value of the lambda sensor and the target lambda value) is preset to a threshold value (reference value). If the range is exceeded (that is, if the lambda error is equal to or greater than a predetermined threshold value) (NO in S111), the controller 105 determines that the air pressure sensor has an abnormality (failure) (S112).

That is, in the present embodiment, when the intake valve is opened, if a pressure drop (ie, the detected pressure drop) occurs within a threshold range according to the throttle valve opening amount and the engine speed, the diagnosis is made to be a normal state. A failure can be diagnosed if the pressure drop (ie, the detected pressure drop) is outside the threshold range.

In this case, when the failure state is diagnosed as described above, the lambda sensor feedback value of the lambda sensor unit 104 is compared with the target lambda value stored in the form of a table, and if the error generated at this time is smaller than the preset reference value, Since the calculated air amount is normal, it can be diagnosed that there is an error in the throttle valve, and if the error is equal to or greater than the reference value, it can be diagnosed as an abnormality of the air pressure sensor.

Although not shown in the drawing, when diagnosed as an abnormality of the air pressure sensor as described above, the controller 105 may convert the air volume model (that is, the air volume model for fuel amount control) based on the throttle valve. In this embodiment, however, it is assumed that there are no failures of the injector, the ignition coil, and the misfire.

As described above, the present embodiment can more reliably diagnose the failure of the air pressure sensor by using a pressure drop amount threshold of the air pressure sensor predetermined according to the throttle valve opening amount and the engine speed. It works.

Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely exemplary, and various modifications and equivalent other embodiments are possible for those skilled in the art to which the art pertains. I will understand the point. Therefore, the technical protection scope of the present invention will be defined by the claims below. Also, implementations described herein may be implemented, for example, as a method or process, apparatus, software program, data stream or signal. Although discussed only in the context of a single form of implementation (eg, discussed only as a method), implementations of the features discussed may also be implemented in other forms (eg, devices or programs). The device may be implemented with suitable hardware, software, firmware, and the like. The method may be implemented in an apparatus such as, for example, a processor, generally referring to a processing device including a computer, microprocessor, integrated circuit or programmable logic device, and the like. The processor also includes communication devices such as computers, cell phones, portable / personal digital assistants ("PDAs") and other devices that facilitate the communication of information between end-users.

101: air pressure sensor unit 102: engine speed detection unit
103: Throttle valve opening amount detection unit 104: Lambda sensor unit
105: control unit 106: pressure drop threshold storage unit
107: diagnostic information output unit

Claims (15)

An air pressure sensor for detecting air pressure of an intake manifold of the vehicle;
An engine rotation speed detection unit detecting rotation speed information of the vehicle engine;
A throttle valve opening amount detecting unit detecting a throttle valve opening amount of the vehicle; And
And a controller configured to determine whether the air pressure sensor or the throttle valve is broken by using a pressure drop amount threshold of a predetermined air pressure sensor according to a throttle valve opening amount and an engine speed.
The controller detects a pressure drop of the intake manifold through the air pressure sensor when the intake valve is opened, and determines that the air pressure sensor is in a normal state when the detected pressure drop is less than or equal to the pressure drop threshold. Failure diagnosis apparatus for a vehicle air pressure sensor, characterized in that.
The method of claim 1,
Lambda sensor for detecting the oxygen concentration in the exhaust gas of the vehicle; further comprising,
The control unit,
If it is determined that the failure state of the air pressure sensor or the throttle valve,
And detecting a lambda error between a lambda sensor feedback value and a target lambda value and determining that the lambda error is less than a specified error threshold value as an abnormality of the throttle valve.
The method of claim 2, wherein the control unit,
And determining that the lambda error is not less than a specified error threshold value as an abnormality of the air pressure sensor.
The method of claim 2, wherein the control unit,
In order to determine the failure state of the air pressure sensor or the throttle valve,
A device for diagnosing a failure of a vehicle air pressure sensor, wherein the target lambda value of the lambda sensor is stored in advance according to the throttle valve opening amount and the engine speed.
The method of claim 1,
Based on the determination result of the controller,
Diagnostic information output unit for guiding the means or the normal state that the abnormality or failure has occurred; fault diagnosis apparatus for a vehicle air pressure sensor further comprises.
The method of claim 1,
The control unit,
In order to determine whether the air pressure sensor or the throttle valve is broken,
And a pressure drop amount threshold storage unit for storing a predetermined pressure drop amount threshold value according to the throttle valve opening amount and the engine speed.
The pressure drop threshold value of claim 6,
An apparatus for diagnosing a failure of a vehicle air pressure sensor, comprising an experimental value in a state where there is no failure in a vehicle air pressure sensor, an injector, an ignition coil, and a misfire means.
The controller checking the opening of the intake valve;
Detecting, by the control unit, a pressure drop of the intake manifold by the air pressure sensor unit when the intake valve is opened;
Comparing, by the control unit, a pressure drop amount threshold value of the air pressure sensor corresponding to the detected pressure drop amount, the throttle valve opening amount, and the engine speed in a designated table; And
And the control unit determines that the air pressure sensor is in a normal state when the detected pressure drop amount is equal to or less than the drawn pressure drop amount threshold value. Diagnostic method.
The method of claim 8,
As a result of the comparison, when the detected pressure drop amount is greater than the drawn pressure drop amount threshold value, the control unit determines that there is an abnormality in any one of an air pressure sensor or a throttle valve. To troubleshoot the vehicle air pressure sensor.
The method of claim 9,
In order for the controller to determine the means by which the abnormality has occurred,
Detecting the feedback value of the lambda sensor according to the throttle valve opening amount and the engine speed, and the lambda error of the target lambda value set in advance corresponding thereto;
And if the lambda error is smaller than a preset threshold, the controller determines that there is an error in the throttle valve.
The method of claim 10,
If the lambda error is greater than or equal to a preset threshold,
And the controller determines that there is an error in the air pressure sensor.
The method of claim 10,
The target lambda value predetermined according to the throttle valve opening amount and the engine speed is pre-stored in a table form.
The method of claim 8, wherein the control unit,
In order to determine whether the air pressure sensor or the throttle valve is broken,
And when the intake valve is opened, the pressure in the intake manifold is dropped by the air drawn into the cylinder.
The method of claim 8, wherein the control unit,
When the intake valve is opened, the opening amount and engine speed of the throttle valve are detected, and the preloaded pressure drop amount threshold value is withdrawn according to the detected opening amount and engine speed of the throttle valve. How to diagnose faults in the air pressure sensor.
The method of claim 14,
The pressure drop amount threshold of the air pressure sensor predetermined according to the throttle valve opening amount and the engine speed is stored in advance in the form of a table.

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