JP3224296B2 - Atmospheric pressure sensor abnormality judgment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for judging an abnormality of an atmospheric pressure sensor, and more particularly to a vehicle equipped with an electronically controlled internal combustion engine for correcting the atmospheric pressure of an air-fuel ratio calculated according to the operating state of the engine. The present invention relates to a device for determining an abnormality of an atmospheric pressure sensor provided.

[0002]

2. Description of the Related Art Conventionally, an air-fuel mixture in an internal combustion engine mounted on a vehicle has been produced by a carburetor. In recent years, as the internal-combustion engine has been electronically controlled, the air-fuel mixture has been controlled by an electronic control circuit. It is being made by injection of fuel from a fuel injection nozzle of an injection device. As a result, the fuel injection amount can be finely controlled according to the operating state of the engine, and the engine is operated at an optimal air-fuel ratio according to the operating state.

In such an electronically controlled internal combustion engine, sensors for detecting operating state parameters of the engine are provided at various parts of the engine in order to obtain an optimum air-fuel ratio according to the operating state of the engine. . For example, a water temperature sensor that detects the temperature of the engine, a rotation speed sensor that detects the rotation speed of the engine, a sensor that detects the intake air amount of the engine, an oxygen concentration sensor that detects the residual oxygen concentration in the exhaust gas, and a pressure of the atmosphere. An atmospheric pressure sensor or the like for detecting is provided.

Among them, the atmospheric pressure sensor is used to correct a change in the intake air mass density or a change in the oxygen concentration in the air due to a change in air pressure when the vehicle travels at high altitude or the like. It is made by a piezoelectric element sensor or the like. In such an electronically controlled internal combustion engine, the electronic control circuit calculates the air-fuel ratio based on the operating state parameter of the engine detected by each sensor. There is a risk that it will not operate normally. Therefore, for example, in a conventional electronically controlled internal combustion engine in which the input voltage of the analog input system becomes 0 to 5 V, an abnormality is determined except when the range is 0.3 V ≦ input voltage ≦ 4.7 V. . The same detection method is used in the above-described atmospheric pressure sensor, which is one of the sensors of the analog input system.

[0005]

However, the atmospheric pressure, which is one of the operating state parameters, is unlikely to change suddenly unlike the negative pressure of the intake air of the engine, so that the conventional 0.3 V ≦ input voltage ≦ 4.7 V. However, even if the atmospheric pressure sensor breaks down in this range and its output changes suddenly, there is a possibility that the abnormality of the atmospheric pressure sensor cannot be detected.

[0006] Therefore, the present invention is the solve the problems of the abnormality detection of the atmospheric pressure sensor in the conventional electronically controlled internal combustion engine, the atmospheric pressure sensor more reliably by utilizing the property of the atmospheric pressure that does not change suddenly originally An object of the present invention is to provide an abnormality determination device for an atmospheric pressure sensor capable of detecting an abnormality.

[0007]

FIG. 1 shows the construction of an apparatus for judging abnormality of an atmospheric pressure sensor according to the present invention which achieves the above object. As shown in FIG. 1, an abnormality determination device for an atmospheric pressure sensor according to the present invention converts atmospheric pressure detection data detected by an atmospheric pressure sensor 1 provided for atmospheric pressure correction of an air-fuel ratio in an electronically controlled internal combustion engine. Atmospheric pressure data storage means 2 for storing
And an atmospheric pressure data comparing means 3 for comparing the detected data from the atmospheric pressure sensor 1 detected this time with stored past detected data, and based on a signal from the comparing means 3,
When the rate of change of the current atmospheric pressure detection data from the past detection data exceeds a reference value and is large, the atmospheric pressure sensor abnormality determining means 4 for determining that the atmospheric pressure sensor 1 is abnormal, and the atmospheric pressure sensor 1 determining that the atmospheric pressure sensor 1 is abnormal. When it is determined, the control unit 5 includes an abnormal-time control unit 5 that controls the fail-safe value to be used as the atmospheric pressure detection data from the atmospheric pressure sensor 1 .
The atmospheric pressure sensor 1 in the abnormality determining means 4 is determined to be abnormal.
The reference value of the rate of change of the detected data
The running state is different from the running state.
The judgment reference value in the line state is the judgment in the stop state
It is characterized by being larger than the reference value.

The fail-safe value includes the last normal data of the detection data from the atmospheric pressure sensor 1 stored in the storage means 2 and the normal detection data from the atmospheric pressure sensor 1 stored in the storage means 2. , Or a preset fixed value stored in the storage means 2 can be used. Further, the atmospheric pressure sensor by the abnormality determination Priority determination means 4 1
When it is determined that is abnormal, the abnormality-time control means 5 may increase the fuel injection amount.

[0009]

According to the abnormality determination device for an atmospheric pressure sensor of the present invention, the atmospheric pressure sensor is determined to be abnormal when the rate of change of the detected atmospheric pressure value from the previous atmospheric pressure sensor exceeds the reference value. Although failsafe value which is prepared separately from the abnormality of the atmospheric pressure sensor is used as an alternative value of the detected value of the atmospheric pressure sensor, the size of this reference value is the vehicle stops
The state that you are doing and the state that you are running are different,
The judgment reference value in the running state is
Because it is larger than the standard value,
It is possible to improve the detection accuracy of the abnormality of the pressure sensor.

[0010]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 2 shows the configuration of an embodiment of an abnormality determination device for an atmospheric pressure sensor according to the present invention. In FIG.
1 is an atmospheric pressure sensor, 6 is a vehicle speed sensor, 10 is an engine control unit (ECU), 20 is an output signal line from the ECU 10, 30 is a fuel supply device, and 40 is an internal combustion engine (engine). The atmospheric pressure sensor 1 is mounted on a part of the vehicle or a part of the ECU 10.

The ECU 10 is constructed using a microcomputer, and has an input buffer 11, a central processing unit (CPU) 12, a read only memory (ROM) 13, and a read / write memory (RA) interconnected by a bus line 16.
M) 14 and an output circuit 15. And
Signals from various sensors provided in the engine and signals from the atmospheric pressure sensor 1 and the vehicle speed sensor 6 are input to the input buffer 11, and an output signal line 20 is connected to the output circuit 15.

Next, an embodiment of a procedure in which the CPU 12 of the ECU 10 in the abnormality determination apparatus for the atmospheric pressure sensor configured as described above determines that the atmospheric pressure sensor 1 is abnormal will be described with reference to the flowcharts of FIGS. explain. FIG. 3 is FIG.
1 shows the procedure of the first embodiment in which the ECU 10 determines that the atmospheric pressure sensor is abnormal.
Executed every ms.

In step 300, the atmospheric pressure sensor abnormality flag FATOM is set to "1" indicating an abnormal state of the atmospheric pressure sensor 1.
It is to determine whether or not. The atmospheric pressure sensor abnormality flag FATOM is "0" at an initial stage, and becomes "1" when it is determined in a later-described step that the atmospheric pressure sensor 1 is abnormal. Therefore, here, the case where the atmospheric pressure sensor 1 is normal will be described first.

In step 301, the atmospheric pressure sensor 1
Is detected. Then, in the subsequent step 302, the detected atmospheric pressure value P is stored in the RAM 14, and in the following step 303, the difference between the present detected atmospheric pressure value P from the atmospheric pressure sensor 1 and the previous detected value Po stored in the RAM 14 is calculated. , That is, the change rate ΔP (= | Po−P
|) Is calculated.

In step 304, it is determined whether or not the calculated change rate ΔP is larger than a reference value α. If ΔP <α, it is determined that the atmospheric pressure sensor 1 is normal, and the routine proceeds to step 307, where the present atmospheric pressure detection value P
Is stored in the RAM 14 as the previous detection value Po, and this routine is terminated. If ΔP ≧ α, the atmospheric pressure sensor 1 is determined to be abnormal, and the routine proceeds to step 305. The reference value α may be determined, for example, as a change rate of the atmospheric pressure that cannot be on the ground.

If it is determined in step 304 that the atmospheric pressure sensor 1 is abnormal, an abnormality determination of the atmospheric pressure sensor is performed in step 305, and a warning sound is emitted from an alarm device in the vehicle compartment or an alarm lamp is turned on. A measure is taken to notify the driver of the abnormality of the atmospheric pressure sensor 1 by turning on the light or the like. Then, the atmospheric pressure sensor abnormality flag FATOM is set to "1" in step 305, and the next step 3
At 06, the use of the detected value of the atmospheric pressure from the atmospheric pressure sensor 1 for correcting the fuel injection amount of the engine is stopped, and the previous normal atmospheric pressure detected value Po is adopted as the fail-safe value of the corrected atmospheric pressure value. The lever routine ends.

In this way, the atmospheric pressure abnormality flag F
When ATOM is set to "1", some action is taken on the atmospheric pressure sensor 1 and the atmospheric pressure abnormality flag FAT
Until OM is reset to “0”, the process proceeds from step 300 to step 306, where the last normal atmospheric pressure detection value P
o is used as a fail-safe value, and the ECU 10 uses this value Po to correct the fuel injection amount of the engine.

As described above, according to the control procedure shown in FIG. 3, in the conventional detection method, only the extreme input voltage abnormality of the atmospheric pressure sensor 1 can detect the abnormality of the atmospheric pressure sensor 1, Although the cause of the malfunction of the engine due to the fluctuation of the voltage cannot be identified, the abnormality of the atmospheric pressure sensor 1 can be detected at an early stage. As a result, even if an abnormality occurs in the atmospheric pressure sensor 1, the engine is operated without malfunction even if it is not optimal.

The flowchart shown in FIG. 4 shows a second embodiment of the procedure in which the ECU 10 in the apparatus for judging abnormality of the atmospheric pressure sensor of the present invention judges that the atmospheric pressure sensor is abnormal. In the procedure of FIG. 3, the atmospheric pressure detection Po of the last normal atmospheric pressure sensor 1 stored in the RAM 14 is used as a fail-safe atmospheric pressure detection value. In the embodiment of FIG. The difference from the embodiment in FIG. 3 is that the value is an average value of a plurality of (N times) normal atmospheric pressure detection values before the atmospheric pressure sensor 1 becomes abnormal. Therefore, the same steps as those in the embodiment described with reference to FIG. 3 are denoted by the same step numbers, and description thereof will be omitted. Only different parts will be described.

In this embodiment, steps 300 to 305 and step 307 are the same as those in FIG. 3 except that step 401 is inserted between steps 302 and 303. In this embodiment, in step 302, the detection value P of the atmospheric pressure sensor 1 is stored in the RAM 14
In step 401, the average value A of the past N normal atmospheric pressure detection values excluding the current storage value P is stored in step 401.
Is calculated as a fail-safe value at the time of abnormality.
Stored in AM14. The latest atmospheric pressure detection value in step 401 may be stored by deleting the oldest data among the N + 1 atmospheric pressure detection values stored in the past.

When the atmospheric pressure sensor 1 is abnormal, at step 305, an atmospheric pressure sensor abnormality flag FATOM
Is set to "1", in step 402, the use of the detected value of the atmospheric pressure from the atmospheric pressure sensor 1 for correcting the fuel injection amount of the engine is stopped, and as a fail-safe value of the atmospheric pressure correction value, the process proceeds to step 401. The average value A of N normal atmospheric pressure detection values calculated in the past is adopted, and this routine ends.

In this manner, the atmospheric pressure abnormality flag F
When ATOM is set to "1", some action is taken on the atmospheric pressure sensor 1 and the atmospheric pressure abnormality flag FAT
Until OM is reset to “0”, the process proceeds from step 300 to step 402, where the average value A is used as a failsafe value, and the ECU 10 uses this value A to correct the fuel injection amount of the engine.

As described above, even if the atmospheric pressure sensor 1 becomes abnormal even in the control procedure shown in FIG. 4, the engine is operated without malfunction even if it is not optimal. The flowchart shown in FIG. 5 shows a third embodiment of the procedure in which the ECU 10 in the abnormality determination device for an atmospheric pressure sensor according to the present invention determines that the atmospheric pressure sensor is abnormal. In the procedure of FIG. 3, the atmospheric pressure detection Po of the last normal atmospheric pressure sensor 1 stored in the RAM 14 is used as a fail-safe atmospheric pressure detection value, but in the embodiment of FIG.
4 differs from the embodiment of FIG. 3 in that the fail-safe value stored in No. 4 is a predetermined fixed value set in advance. Therefore, the same steps as those in the embodiment described with reference to FIG. 3 are denoted by the same step numbers, and description thereof will be omitted. Only different parts will be described.

In this embodiment, steps 300 to 305 and step 307 are the same as those in FIG. Then, when the atmospheric pressure sensor 1 is abnormal, step 3
After the atmospheric pressure sensor abnormality flag FATOM is set to "1" in step 05, the use of the detected value of the atmospheric pressure from the atmospheric pressure sensor 1 for correcting the fuel injection amount of the engine is stopped in step 501, and the atmospheric pressure correction value A fixed value set in advance is adopted as the fail-safe value of, and this routine ends.

In this way, the atmospheric pressure abnormality flag F
When ATOM is set to "1", some action is taken on the atmospheric pressure sensor 1 and the atmospheric pressure abnormality flag FAT
Until OM is reset to “0”, the process proceeds from step 300 to step 501, where the fixed value is used as a failsafe value, and the ECU 10 uses this fixed value to correct the fuel injection amount of the engine.

In this manner, even if the atmospheric pressure sensor 1 is abnormal even in the control procedure shown in FIG. 5, the engine is operated without malfunction even in a non-optimal state. The flowchart shown in FIG. 6 shows a fourth embodiment of the procedure in which the ECU 10 in the abnormality determination device for an atmospheric pressure sensor according to the present invention determines that the atmospheric pressure sensor is abnormal. In the procedure shown in FIG. 3, the atmospheric pressure detection Po of the last normal atmospheric pressure sensor 1 stored in the RAM 14 is used as the fail-safe atmospheric pressure detection value regardless of whether the vehicle is running or stopped. 3 differs from the embodiment in FIG. 3 in that the reference value for determining that the atmospheric pressure sensor 1 is abnormal when the vehicle is running or stopped is changed. Also in this embodiment, the same steps as those in the embodiment described with reference to FIG. 3 are denoted by the same step numbers, and the description thereof will be omitted. Only different parts will be described.

In this embodiment, steps 300 to 303, steps 304 to 306, and step 307 are the same as those in FIG. This embodiment is different from the embodiment of FIG. 3 in that step 601 is inserted between step 303 and step 304 to determine whether the vehicle is running or stopped based on the vehicle speed detected by the vehicle speed sensor 6. It was done. That is, after calculating the change rate ΔP of the detected atmospheric pressure value in step 303, it is determined in step 601 whether or not the vehicle speed is greater than 0. If the vehicle speed is greater than 0, step 304 and subsequent steps are performed similarly to the embodiment of FIG. When the vehicle speed = 0, the process proceeds to step 602, and the reference value for determining that the atmospheric pressure sensor 1 is abnormal is set to the reference value β smaller than the reference value α in step 304.

This is because, when the vehicle is stopped, the possibility of sudden change in the atmospheric pressure is much lower than when the vehicle is running. Therefore, the width of the rate of change ΔP of the detected value of the atmospheric pressure sensor 1 used for abnormality determination is reduced. By doing so, the accuracy of abnormality detection when the vehicle is stopped can be improved. And step 60
In step 2, when ΔP <β, this routine ends, and ΔP <β
When P ≧ β, the process proceeds to step 305 and thereafter, and the same procedure as in FIG. 3 is performed.
After the atmospheric pressure sensor abnormality flag FATOM is set to "1" in step 501, the use of the detected value of the atmospheric pressure from the atmospheric pressure sensor 1 for correcting the fuel injection amount of the engine is stopped in step 501, and The previous atmospheric pressure detection value Po is adopted as the failsafe value, and this routine ends.

In this way, the atmospheric pressure abnormality flag F
When ATOM is set to "1", some action is taken on the atmospheric pressure sensor 1 and the atmospheric pressure abnormality flag FAT
Until OM is reset to “0”, the process proceeds from step 300 to step 306, where the previous atmospheric pressure detection value Po is used as a failsafe value, and the ECU 10 corrects the fuel injection amount of the engine using this fixed value. Execute.

In this embodiment, the atmospheric pressure abnormality flag F
After ATOM is set to "1", the previous atmospheric pressure detection value Po was used as the failsafe value in step 306, but the average of the past normal N atmospheric pressure detection values described in step 402 of FIG. The value A or the predetermined fixed value described in step 501 of FIG. 5 may be used as the failsafe value.

As described above, even in the control procedure shown in FIG. 6, even if an abnormality occurs in the atmospheric pressure sensor 1, the engine is operated without malfunction even in a non-optimal state. The flowchart shown in FIG. 7 shows a fifth embodiment of the procedure in which the ECU 10 in the abnormality determination device for the atmospheric pressure sensor of the present invention determines that the atmospheric pressure sensor is abnormal, and is a modification of the embodiment of FIG. is there. That is, in the embodiment of FIG. 6, the reference value for determining that the atmospheric pressure sensor 1 is abnormal when the vehicle is running or stopped is changed. However, in the embodiment of FIG. Only the decision to stop the rate is shown in FIG.
Is different from the embodiment. Therefore, further description of this embodiment will be omitted.

The flowchart shown in FIG. 8 shows a sixth embodiment of the procedure in which the ECU 10 in the apparatus for judging abnormality of the atmospheric pressure sensor of the present invention judges that the atmospheric pressure sensor is abnormal. In the procedure of FIG. 3, the atmospheric pressure detection Po of the last normal atmospheric pressure sensor 1 stored in the RAM 14 is used as a fail-safe atmospheric pressure detection value, but in the embodiment of FIG. 8, the atmospheric pressure sensor 1 becomes abnormal. The embodiment differs from the embodiment of FIG. 3 in that the fuel injection amount is increased instead of using the fail-safe value at the time.

When the detection value from the atmospheric pressure sensor 1 changes suddenly, the fuel may be too thin with a normal fuel injection amount and the engine may stop. Therefore, in this embodiment, when the atmospheric pressure sensor 1 is determined to be abnormal, the fuel injection amount is increased from the normal injection amount so that the engine does not stop. Here, the same steps as those in the embodiment described with reference to FIG. 3 are denoted by the same step numbers, and the description thereof will be omitted. Only different parts will be described.

In this embodiment, steps 300 to 305 and the stage 307 are the same as those in FIG. Then, when the atmospheric pressure sensor 1 is abnormal, the atmospheric pressure sensor abnormality flag FATOM is set to “1” in step 305, and then in step 801 the engine 4
A command is issued to the zero fuel supply device 30, and the fuel injection amount is increased from the normal amount, and this routine ends.

In this way, the atmospheric pressure abnormality flag F
When ATOM is set to "1", some action is taken on the atmospheric pressure sensor 1 and the atmospheric pressure abnormality flag FAT
Until OM is reset to “0”, the process proceeds from step 300 to step 801 to increase the fuel injection amount. In this way, even if the atmospheric pressure sensor 1 becomes abnormal even in the control procedure shown in FIG. 8, the engine is operated without stopping even in a non-optimal state.

[0036]

As described above, according to the apparatus for judging abnormality of the atmospheric pressure sensor of the present invention, the abnormality of the atmospheric pressure sensor can be detected more quickly by utilizing the property of the atmospheric pressure which is not suddenly changed. There is an effect that it can be detected.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a principle configuration of an abnormality determination device for an atmospheric pressure sensor according to the present invention.

FIG. 2 is a block circuit diagram showing a configuration of an embodiment of an abnormality determination apparatus for an atmospheric pressure sensor according to the present invention.

FIG. 3 is a flowchart showing a control procedure of a first embodiment of a control operation of the ECU of FIG. 2;

FIG. 4 is a flowchart illustrating a control procedure of a second embodiment of the control operation of the ECU in FIG. 2;

FIG. 5 is a flowchart showing a control procedure of a third embodiment of the control operation of the ECU of FIG. 2;

FIG. 6 is a flowchart showing a control procedure according to a fourth embodiment of the control operation of the ECU of FIG. 2;

FIG. 7 is a flowchart showing a control procedure according to a fifth embodiment of the control operation of the ECU of FIG. 2;

FIG. 8 is a flowchart showing a control procedure of a sixth embodiment of the control operation of the ECU of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Atmospheric pressure sensor 2 ... Atmospheric pressure data storage means 3 ... Atmospheric pressure data comparison means 4 ... Atmospheric pressure sensor abnormality determination means 5 ... Abnormality control means 6 ... Vehicle speed sensor 10 ... ECU 11 ... Input buffer 12 ... Central processing unit ( CPU) 13 Read-only memory (ROM) 14 Read-write memory (RAM) 15 Output circuit 20 Signal line 30 Fuel supply device 40 Internal combustion engine (engine)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-32953 (JP, A) JP-A-64-35053 (JP, A) JP-A-63-70019 (JP, U) (58) Field (Int. Cl. ⁷ , DB name) F02D 41/00-45/00 395

Claims (5)

(57) [Claims] In an electronically controlled internal combustion engine mounted on a vehicle, an apparatus for determining an abnormality of an atmospheric pressure sensor provided for correcting an atmospheric pressure of an air-fuel ratio calculated according to an operation state of the engine. Atmospheric pressure data storage means for storing the detected atmospheric pressure data detected by the atmospheric pressure sensor, and atmospheric pressure data comparison for comparing the detected data from the atmospheric pressure sensor detected this time with the stored past detected data. Means for determining that the atmospheric pressure sensor is abnormal when the change rate of the current atmospheric pressure detection data from the past detection data exceeds a reference value based on a signal from the comparison means. Means, when the atmospheric pressure sensor is determined to be abnormal, abnormal time control means for controlling to use a fail-safe value as atmospheric pressure detection data from the atmospheric pressure sensor Comprising, in the abnormality determining means, an atmospheric pressure sensor abnormality determination
The magnitude of the reference value of the rate of change of the detected data
The difference between the stationary state and the traveling state
The judgment reference value in the state is the judgment base in the stop state.
An abnormality determination device for an atmospheric pressure sensor, wherein the abnormality is larger than a reference value . 2. The abnormality of the atmospheric pressure sensor according to claim 1, wherein the fail safe value is the last normal data of the detection data from the atmospheric pressure sensor stored in the storage unit. Judgment device. 3. The abnormality determination of the atmospheric pressure sensor according to claim 1, wherein the fail-safe value is an average value of normal detection data from the atmospheric pressure sensor stored in the storage unit. apparatus. 4. The apparatus according to claim 1, wherein the fail-safe value is a preset fixed value stored in the storage unit. The method according to claim 5, wherein said abnormality determination means when the atmospheric pressure sensor is determined to be abnormal, in claim 1, characterized in that the increase of the fuel injection amount is performed by the abnormality control unit
An abnormality determination device for an atmospheric pressure sensor as described in the above .