JP6396777B2 - Electronic control unit for automobile - Google Patents

Description

  The present invention relates to an automotive electronic control device, and more specifically, in an automotive electronic control device including an AD converter that inputs an analog output signal of a sensor and converts it into a digital signal, the presence or absence of an output abnormality of the AD converter is checked. It relates to the technology to detect.

  Patent Document 1 discloses an input terminal to which an analog input voltage is input, a DA converter, a comparator that compares the analog input voltage and an output voltage of the DA converter, and a conversion result output from the comparator. A successive approximation register to store; a generation unit that generates addition digital data and subtraction digital data obtained by adding and subtracting a predetermined value to the conversion result held by the successive approximation register; and the DA conversion unit includes the addition digital data and There is disclosed an AD converter including a determination unit that determines whether or not a failure has occurred using a result of comparing each output level obtained by converting subtracted digital data and the analog input voltage.

JP 2014-090362 A

  By the way, when it is set as the structure which detects the presence or absence of the output abnormality of AD converter using a dedicated diagnostic circuit, it leads to the cost increase of an electronic control apparatus, and the output value of AD converter is in a normal range. If the configuration is such that the presence or absence of an output abnormality of the AD converter is detected based on the above, there is a problem that the abnormality that the output value of the AD converter stops within the normal range cannot be detected.

  The present invention has been made in view of the above problems, and an automobile capable of detecting an output abnormality of an AD converter including an abnormality in which an output value of the AD converter stops within a normal range without using a dedicated diagnostic circuit. An object of the present invention is to provide an electronic control device.

Therefore, an automotive electronic control device according to the present invention is an automotive electronic control device including an AD converter that inputs an analog output signal of a sensor and converts it into a digital signal, and is based on the output of the AD converter. The detected first control parameter is compared with the second control parameter that is obtained from the output of a sensor different from the sensor that detects the first control parameter and changes in correlation with the first control parameter. And a diagnostic means for detecting the presence or absence of an output abnormality of the AD converter.
Here, in the diagnostic means, the first control parameter and the second control parameter are state quantities different from each other, and the second control parameter is a control parameter detected based on an output of the AD converter. Can do.
Further, the diagnosis means can detect the presence or absence of an output abnormality of the AD converter by comparing the change speed of the first control parameter and the change speed of the second control parameter.

  According to the above invention, it is possible to detect the presence or absence of an output abnormality of the AD converter including an abnormality that stops (fixes) the output of the AD converter within a normal range without providing a dedicated diagnostic circuit.

It is a block diagram which shows an example of the electronic controller for motor vehicles. It is a flowchart which shows an example of the diagnostic process of AD converter. It is a diagram which illustrates the correlation between the throttle opening and the intake air flow rate in an example of the diagnostic processing of the AD converter. It is a flowchart which shows an example of the diagnostic process of AD converter. FIG. 4 is a diagram illustrating the correlation between the engine speed and the vehicle speed and the throttle opening, and the correlation between the engine speed and the vehicle speed and the intake air flow rate in an example of the AD converter diagnosis process.

Embodiments of the present invention will be described below.
FIG. 1 is a block diagram showing an example of an automotive electronic control device according to the present invention.
1 is a device that controls a traveling engine (internal combustion engine) 200 mounted on a vehicle as an example, and includes a CPU 101, a ROM 102, a RAM 103, an AD converter (analog-digital conversion circuit) 104. And a microcomputer including a pulse input circuit 105, a digital output circuit 106, a pulse output circuit 107, and the like.

The engine 200 includes a throttle sensor 201 that outputs a voltage signal corresponding to the throttle opening (accelerator opening) TVO, a hot-wire airflow sensor 202 that outputs a voltage signal corresponding to the intake air flow rate QA of the engine 200, a crank Various sensors such as a crank angle sensor 203 that outputs a pulse signal POS synchronized with the rotation of the shaft are provided, and a vehicle speed sensor 204 that outputs a pulse signal synchronized with the rotation of the drive shaft is provided on the vehicle drive shaft. It has been.
Further, the engine 200 is provided with various relays 211, a fuel injection valve 212, an ignition coil 213 with a built-in power transistor, and the like as devices controlled by the output from the electronic control unit 100.

  The AD converter 104 of the electronic control apparatus 100 inputs voltage signals (analog output signals) output from various sensors (voltage output sensors) such as the throttle sensor 201 and the air flow sensor 202, and converts them into digital signals. The digital signal output from the AD converter 104 is stored in a buffer (such as the RAM 103) via a register (not shown) and used as a control parameter by the CPU 101.

Further, the pulse input circuit 105 of the electronic control device 100 inputs pulse signals output from various sensors (pulse output sensors) such as the crank angle sensor 203 and the vehicle speed sensor 204, and measures the period of the pulse signal or within a predetermined time. Count the number of generated pulses.
Period data, count data, and the like output from the pulse input circuit 105 are stored in a buffer via a register (not shown) and used as a control parameter by the CPU 101.

Then, the CPU 101 calculates a plurality of control parameters according to a program stored in the ROM 102, thereby determining control pulse signals such as power transistors built in the fuel injection valve 213 and the ignition coil 214, and the control pulses A signal is output from the pulse output circuit 107 to each device.
In addition, the CPU 101 calculates a plurality of control parameters CP according to a program stored in the ROM 102 to determine on / off of various relays 211 and the like. Output to the device.

Further, the CPU 101 performs a diagnostic process for detecting the presence or absence of an output abnormality of the AD converter 104 (failure of the AD converter 104) according to a program stored in the ROM 102.
The flowchart in FIG. 2 shows an example of a diagnostic process performed by the CPU 101.
The processing shown in the flowchart of FIG. 2 is interrupted by the CPU 101 every predetermined time.

In step S <b> 501, the CPU 101 uses a preselected one of a plurality of control parameters (state amount detection values) obtained from the digital output value of the AD converter 104 for output abnormality of the AD converter 104. 1 is read as control parameter CP1.
In the next step S502, the CPU 101 detects one of the digital output values of the AD converter 104, which is detected by a sensor different from the sensor that detects the first control parameter, and correlates with the first control parameter. The second control parameter CP2 selected in advance as the control parameter to be changed is read.

  For example, the first control parameter CP1 is throttle opening data (opening detection value) TVO obtained by converting the voltage signal output from the throttle sensor 201 into a digital signal by the AD converter 104, and the second control parameter CP1. CP2 is intake air flow rate data (flow rate detection value) QA obtained by converting the voltage signal output from the air flow sensor 202 into a digital signal by the AD converter 104.

FIG. 3 exemplifies changes in the throttle opening TVO and the intake air flow rate QA in a transient state of the engine 200. The change amount (change speed) per unit time of the throttle opening TVO and the intake air flow rate QA. The amount of change per unit time (rate of change).
As shown in FIG. 3, the throttle opening TVO and the intake air flow rate QA are state quantities that change in correlation with each other. When one increases, the other increases, and when one decreases, the other decreases. Both speeds of change change in correlation with each other.

  Next, the CPU 101 proceeds to step S503, where the ratio R1 (R1 = CP1) between the amount of change (change rate) per unit time of the first control parameter CP1 and the amount of change (change rate) per unit time of the second control parameter CP2. Change amount / change amount of CP2).

The CPU 101 corrects at least one of the changing speed of the first control parameter CP1 and the changing speed of the second control parameter CP2 according to a predetermined function, and calculates the ratio R1 based on the corrected control parameters CP1 and CP2. Can do.
Further, the CPU 101 calculates the ratio (R1 = CP1 / CP2) of the first control parameter CP1 and the second control parameter CP2 instead of calculating the ratio R1 of the change amount (change speed) per unit time of the control parameters CP1 and CP2. ) Can be calculated.

Next, in step S504, the CPU 101 detects whether or not the ratio R1 is a value within an area sandwiched between the lower limit threshold MIN1 and the upper limit threshold MAX1 (MIN1 <MAX1).
The lower limit threshold value MIN1 and the upper limit threshold value MAX1 are such that the ratio R1 deviates from a region sandwiched between the lower limit threshold value MIN1 and the upper limit threshold value MAX1 when the throttle sensor 201 and the airflow sensor 202 are normal and the AD converter 104 is normal. It is adapted beforehand by experiment and simulation as a value that is not to be performed.

When the ratio R1 is a value (MIN1 ≦ R1 ≦ MAX1) within an area (normal range) sandwiched between the lower limit threshold value MIN1 and the upper limit threshold value MAX1, that is, the intake air flow rate is linked to the increase / decrease change of the throttle opening data TVO. If the data QA has changed, the CPU 101 proceeds to step S505, clears the counter C1 (resets to zero), and determines in the next step S506 that the output of the AD converter 104 is normal.
In the normal state of the AD converter 104, the CPU 101 normally performs control of the engine 200 (such as fuel injection control and ignition timing control) using the control parameter based on the output of the AD converter 104.

The CPU 101 performs failure diagnosis of each sensor separately from the diagnosis of the AD converter 104 described above, and diagnoses whether there is an abnormality in the output of the AD converter 104 when the sensor is normal. It is possible to distinguish the failure of the AD converter 104.
For example, multiple throttle sensors 201 can be provided, and the CPU 101 can detect whether one of the plurality of throttle sensors 201 is out of order by detecting whether the detection outputs of the plurality of throttle sensors 201 match. it can. Then, the CPU 101 diagnoses whether the AD converter 104 is operating normally by diagnosing the AD converter 104 in a normal state of the throttle sensor 201 in which the detection outputs of the plurality of throttle sensors 201 match. be able to.

On the other hand, if the ratio R1 is not a value within the range between the lower limit threshold value MIN1 and the upper limit threshold value MAX1, in other words, if the throttle opening data TVO and the intake air flow rate data QA do not change in conjunction with each other, the CPU 101 Advances to step S507 to increment the counter C1. That is, the CPU 101 increments the counter C1 when the ratio R1 is lower than the lower limit threshold MIN1, and also increments the counter C1 when the ratio R1 is higher than the upper limit threshold MAX1.
For example, when the intake air amount data QA as the second control parameter CP2 maintains a constant value when the throttle opening data TVO as the first control parameter CP1 is increasing, the ratio R1 is in the normal range (upper limit MAX1). The CPU 101 increments the counter C1.

For example, when the intake air amount data QA holds a constant value when the throttle opening data TVO is decreasing, the ratio R1 is lower than the normal range (lower limit threshold MIN1), and the CPU 101 increments the counter C1. .
Conversely, when the throttle opening data TVO maintains a constant value when the intake air amount data QA changes, the ratio R1 deviates from the normal range (the region sandwiched between the lower limit threshold MIN1 and the upper limit threshold MAX1). The CPU 101 increments the counter C1.

Since the throttle opening TVO (first control parameter CP1) and the intake air amount QA (second control parameter CP2) change in synchronization with each other as illustrated in FIG. 3, the CPU 101 determines that these control parameters are Whether or not the tuning is changed is detected based on a comparison between the ratio R1 and the thresholds MIN1 and MAX1.
If the intake air amount data QA and the throttle opening data TVO do not change in synchronization, there is a possibility that an output abnormality of the AD converter 104 (failure of the AD converter 104) has occurred. The CPU 101 updates the abnormality determination history by incrementing the counter C1.

After incrementing the counter C1 in step S507, the CPU 101 proceeds to step S508 and detects whether or not the value of the counter C1 is equal to or greater than the threshold value SL1.
If the value of the counter C1 is less than the threshold value SL1, a state in which the ratio R1 deviates from the normal range (determination of output abnormality of the AD converter 104) is temporarily caused by noise or the like. Since there is a possibility that the AD converter 104 is operating normally, the CPU 101 terminates the current diagnosis process without making a final abnormality determination.

On the other hand, when the value of the counter C1 is equal to or greater than the threshold value SL1, it is estimated that the ratio R1 is continuously deviating from the normal range and that the AD converter 104 is abnormal (failure). The CPU 101 proceeds to step S509, and determines the occurrence of an output abnormality of the AD converter 104.
The threshold value SL1 is adapted in advance through experiments and simulations so that the counter C1 does not exceed when the ratio R1 temporarily shows an abnormal value due to noise or the like.
In other words, when the value of the counter C1 is equal to or greater than the threshold value SL1, the state where the ratio R1 is an abnormal value is not affected by noise or the like, but is caused by an output abnormality (failure) of the AD converter 104. The threshold SL1 is adapted so that it can be determined that it is.

As described above, the CPU 101 compares the control parameters CP1 and CP2 that change in correlation with each other among the control parameters obtained by converting the analog output of the sensor into a digital signal by the AD converter 104. The presence or absence of output abnormality of the converter 104 is diagnosed.
Thereby, the CPU 101 can detect an output abnormality (operation failure) of the AD converter 104 including an abnormality in which the AD-converted digital signal is fixed in the normal region without using a dedicated diagnostic circuit.

  When the CPU 101 detects the occurrence of an output abnormality of the AD converter 104, the CPU 101 can correctly recognize the state in which the analog output (voltage signal) of the sensor cannot be read correctly, in other words, the operating state of the engine 200. Since this is not possible, fail-safe processing such as restricting changes in the throttle opening and the fuel injection amount to a predetermined low range is performed.

  By the way, in the diagnosis processing shown in the flowchart of FIG. 2, the CPU 101 compares the control parameters based on the output of the AD converter 104 to diagnose the presence or absence of an output abnormality of the AD converter 104. By comparing the first control parameter CP1 based on the output of 104 and the second control parameter CP2 obtained from the output of the pulse input circuit 105, the presence or absence of an output abnormality of the AD converter 104 can be diagnosed.

The flowchart of FIG. 4 compares the first control parameter CP1 based on the output of the AD converter 104 with the second control parameter CP2 obtained from the output of the pulse input circuit 105 to determine whether there is an output abnormality of the AD converter 104. An example of a diagnosis process of the CPU 101 for diagnosing
The processing shown in the flowchart of FIG. 4 is interrupted by the CPU 101 every predetermined time.

In step S <b> 601, the CPU 101 uses a preset one of a plurality of control parameters (state amount detection values) obtained from the digital output value of the AD converter 104 for the output abnormality of the AD converter 104. Read as control parameter CP1.
In next step S602, the CPU 101 calculates an expected value Aex (second control parameter) of the first control parameter CP1 based on a plurality of control parameters obtained from the output of the pulse input circuit 105.

  For example, the first control parameter CP1 is throttle opening data (opening detection value) TVO obtained by converting the voltage signal output from the throttle sensor 201 into a digital signal by the AD converter 104, and the expected value Aex is calculated. A plurality of control parameters used in the above are the detection data of the engine speed NE (rpm) obtained by the pulse input circuit 105 from the pulse signal output from the crank angle sensor 203 and the pulse input circuit 105 from the pulse signal output from the vehicle speed sensor 204. It is the detection data of the vehicle speed VSP (km / h) calculated | required by (5).

As illustrated in FIG. 5, when the engine speed NE is high and the vehicle speed VSP is high, the throttle opening degree TVO is high. Conversely, when the engine speed NE is low and the vehicle speed VSP is low, the throttle opening degree TVO is high. This is a low state, and the throttle opening TVO at that time can be roughly estimated from the engine speed NE and the vehicle speed VSP.
Therefore, the CPU 101 estimates the throttle opening TVO at that time based on the engine speed NE and the vehicle speed VSP both obtained from the pulse output of the sensor, and calculates the estimated value from the output of the AD converter 104. Set to the expected value Aex of the degree data TVO.

Further, instead of the throttle opening data TVO, the intake air flow rate data QA obtained by converting the voltage signal output from the airflow sensor 202 into a digital signal by the AD converter 104 can be used as the first control parameter CP1. .
As illustrated in FIG. 5, when the engine speed NE is high and the vehicle speed VSP is high, the intake air flow rate QA is high. Conversely, when the engine speed NE is low and the vehicle speed VSP is low, the intake air flow rate QA is low. In this state, the intake air flow rate QA at that time can be roughly estimated from the engine speed NE and the vehicle speed VSP.

Therefore, the CPU 101 estimates the intake air flow rate QA at that time based on the engine speed NE and the vehicle speed VSP, both of which are obtained from the pulse output of the sensor, and the estimated value is obtained from the output of the AD converter 104. The expected value Aex of the data QA is set.
For example, when the vehicle is in a stopped state (the vehicle speed VSP is substantially zero) and the engine rotational speed NE is in the idle rotational speed range (the vehicle is in an idle stopped state), the diagnostic execution condition is satisfied. In some cases, the expected value Aex can be set by estimating that the throttle opening TVO or the intake air flow rate QA is within a predetermined range.

When the CPU 101 sets the expected value Aex in step S602, in step S603, the change amount (change speed) per unit time of the first control parameter CP1 and the expected value Aex of the first control parameter CP1 per unit time. A ratio R2 (R2 = change amount of CP1 / change amount of Aex) with the change amount (change speed) is calculated.
Here, the CPU 101 can set the ratio of the first control parameter CP1 and the expected value Aex of the first control parameter CP1 to R2 (R2 = CP1 / Aex).

In the next step S604, the CPU 101 detects whether or not the ratio R2 is a value within an area sandwiched between the lower limit threshold value MIN2 and the upper limit threshold value MAX2 (MIN2 <MAX2).
The lower limit threshold value MIN2 and the upper limit threshold value MAX2 are the lower limit threshold value MIN2 when the sensors (throttle sensor 201 and airflow sensor 202) whose analog outputs are input to the AD converter 104 are normal and the AD converter 104 is normal. And the range between the upper threshold MAX2 and the ratio R2 does not deviate in advance, and is adapted in advance through experiments and simulations.

When the ratio R2 is a value within the region (normal range) sandwiched between the lower limit threshold value MIN2 and the upper limit threshold value MAX2, that is, when MIN2 ≦ R2 ≦ MAX2 is satisfied, the CPU 101 proceeds to step S605 and clears the counter C2 ( In step S606, it is determined that the output of the AD converter 104 is normal.
In the normal state of the AD converter 104, the CPU 101 normally performs control of the engine 200 (such as fuel injection control and ignition timing control) using the control parameter based on the output of the AD converter 104.

On the other hand, when the ratio R2 is not a value within the region between the lower limit threshold value MIN2 and the upper limit threshold value MAX2, that is, when the fluctuation of the throttle opening data TVO (intake air flow rate data QA) does not match the fluctuation of the expected value Aex. In step S607, the CPU 101 increments the counter C2.
In other words, the CPU 101 increments the counter C2 when the ratio R2 is less than the lower limit threshold MIN2, and also increments the counter C2 when the ratio R2 is greater than the upper limit threshold MAX2.

For example, when the throttle opening data TVO (intake air flow rate data QA) as the first control parameter holds a constant value when the expected value Aex of the throttle opening TVO is increasing, the ratio R2 is within the normal range ( The CPU 101 increments the counter C2.
Also, for example, when the throttle opening data (intake air flow rate data QA) as the first control parameter holds a constant value when the expected value Aex of the throttle opening TVO is decreasing, the ratio R2 is in the normal range. It becomes higher than (upper limit threshold MAX2), and the CPU 101 increments the counter C2.

  As described above, the CPU 101 detects whether or not the throttle opening data TVO or the intake air amount data QA changes in synchronization with the expected value Aex based on the comparison between the ratio R2 and the threshold values MIN2 and MAX2, and the throttle When the opening degree data TVO or the intake air amount data QA does not change in synchronization with the expected value Aex, there is a possibility that an output abnormality of the AD converter 104 has occurred. Therefore, the abnormality determination history is obtained by incrementing the counter C2. Update.

After incrementing the counter C2 in step S607, the CPU 101 proceeds to step S608 and detects whether or not the counter value C2 is equal to or greater than the threshold value SL2.
If the value of the counter C2 is less than the threshold value SL2, there is a possibility that the state where the ratio R2 deviates from the normal range is temporarily affected by noise or the like and is not an abnormality (failure) of the AD converter 104. Therefore, the CPU 101 ends the diagnosis process without making a final abnormality determination.

On the other hand, when the value of the counter C2 becomes equal to or greater than the threshold value SL2, it is estimated that the ratio R2 is continuously deviating from the normal range and that the AD converter 104 is abnormal (failure). The CPU 101 proceeds to step S609, and determines whether an output abnormality of the AD converter 104 has occurred.
The threshold value SL2 is previously adapted by experiments and simulations so that the counter C2 does not exceed when the ratio R2 temporarily shows an abnormal value due to the influence of noise or the like.
In other words, when the value of the counter C2 is equal to or greater than the threshold value SL2, the state in which the ratio R2 is an abnormal value is not affected by noise or the like, but is caused by an output abnormality of the AD converter 104. The threshold SL2 is adapted so that it can be determined that

  As described above, the CPU 101 uses the first control parameter (state value detection values such as the throttle opening TVO and the intake air flow rate QA) obtained by converting the analog output of the sensor into a digital signal by the AD converter 104, and the pulse. AD conversion is performed by comparing the expected value (predicted value) Aex of the first control parameter estimated from the control parameter (state quantity detection value such as engine speed NE and vehicle speed VSP) obtained from the sensor that generates the output. Therefore, the presence / absence of output abnormality of the AD converter 104 can be detected without using a dedicated diagnostic circuit.

In addition, the control parameters (state quantity detection values such as the engine speed NE and the vehicle speed VSP) used to determine the expected value Aex are not values obtained by analog / digital conversion by the AD converter 104, but sensors that output pulse signals. This value is detected by the pulse input circuit 105 that inputs the above signal and does not fluctuate due to the normality / abnormality of the AD converter 104.
Therefore, the first control parameter CP1 that is affected by the normality / abnormality of the AD converter 104 and the expected value Aex that is not affected by the normality / abnormality of the AD converter 104 are compared.

  Therefore, the output abnormality of the AD converter 104 appears as a deviation of the first control parameter CP1 from the expected value Aex which is a normal value. In other words, the abnormality of the first control parameter CP1, in other words, the AD converter 104 Output abnormality can be detected with higher accuracy.

Although the contents of the present invention have been specifically described above with reference to the preferred embodiments, it is obvious that those skilled in the art can take various modifications based on the basic technical idea and teachings of the present invention. is there.
For example, in the above embodiment, the CPU 101 determines from the first control parameter CP1 (or the change rate of the first control parameter CP1) obtained by analog / digital conversion of the sensor output by the AD converter 104 and the output of another sensor. Based on the ratio of the obtained control parameter to the second control parameter CP2 that changes in correlation with the first control parameter (or the change speed of the second control parameter CP2), the presence or absence of output abnormality of the AD converter 104 is determined. Although the diagnosis is made, the difference between the first control parameter and the second control parameter and the threshold value can be compared to diagnose the presence or absence of an output abnormality of the AD converter 104.

Further, the first control parameter CP1 is not limited to the throttle opening TVO and the intake air amount QA. For example, output signals (voltage signals) of various temperature sensors are converted into digital signals by the AD converter 104. In the configuration, the temperature data can be the first control parameter CP1.
Then, for example, the CPU 101 sets the engine coolant temperature as the first control parameter CP1, sets the lubricating oil temperature that changes in correlation with the coolant temperature as the second control parameter PC2, and compares them to compare the AD converter 104. The presence or absence of output abnormality can be diagnosed.

  Further, the CPU 101 sets the first control parameter CP1 as the coolant temperature or the lubricating oil temperature, estimates the expected value Aex of these temperatures from the vehicle speed and the engine speed, and sets the expected value Aex (second control parameter CP2) and the first control. By comparing with the parameter CP1, it is possible to diagnose the presence or absence of output abnormality of the AD converter 104.

  For example, when the electronic control unit 100 detects the intake negative pressure data by converting the output of a sensor that outputs a voltage signal according to the intake negative pressure (boost) of the engine by the AD converter 104, the intake negative pressure data is detected. The pressure data is the first control parameter CP1 or the second control parameter CP2, the throttle opening data TVO or the intake air amount data QA is the second control parameter CP2 or the first control parameter CP1, and the first control parameter CP1 and the second control parameter CP1 By comparing with the control parameter CP2, it is possible to diagnose the presence or absence of output abnormality of the AD converter 104.

  Further, the CPU 101 sets the intake negative pressure data as the first control parameter CP1, sets the intake negative pressure estimated from the vehicle speed VSP and the engine speed NE as the expected value Aex (second control parameter CP2), and sets the first control parameter CP1. The expected value Aex can be compared to diagnose the presence or absence of an output abnormality of the AD converter 104.

  Further, the CPU 101 compares the control parameters CP1 and CP2 obtained from the output of the AD converter 104, and further obtains at least one of the control parameters CP1 and CP2 from a sensor that generates a pulse output. An expected value Aex can be obtained based on a plurality of control parameters, and the expected value Aex can be compared with the control parameter.

  In the above-described embodiment, the CPU 101 determines that the output error of the AD converter 104 is abnormal when the number of consecutive times that the ratios R1 and R2 (or difference) deviate from the normal range is equal to or greater than the thresholds SL1 and SL2. However, the counting process of continuous times can be omitted. That is, the CPU 101 can determine an output abnormality of the AD converter 104 when the ratios R1, R2 (or differences) deviate from the normal range.

Further, the CPU 101 can switch to fail-safe processing for limiting the engine output to a lower level in accordance with an increase in the number of consecutive times when the ratios R1 and R2 (or differences) deviate from the normal range.
Further, the CPU 101 increases the step width when incrementing the counters C1 and C2 as the difference between the ratios R1 and R2 (or difference) and the normal range (normal value) increases, and determines the final abnormality determination timing. You can expedite.

In addition, the control target of the electronic control device 100 for an automobile is not limited to the engine 200. For example, the diagnosis processing of the AD converter according to the present invention is also applied to the electronic control device 100 for an automobile that controls an automatic transmission. It is possible.
For example, in the case of an automotive electronic control apparatus 100 that controls an automatic transmission, analog signals such as a voltage signal of an oil temperature sensor that detects the temperature of AT fluid and a voltage signal of a pressure sensor that detects oil pressure are passed through an AD converter. Then, a pulse signal such as a pulse signal of a rotation sensor that detects the rotation speed (rpm) of the input shaft is read into the CPU 101 via a pulse input circuit (signal detection circuit).
Then, the CPU 101 uses detection data such as oil temperature and hydraulic pressure as the first control parameter, and compares the second control parameter that changes in correlation with the first control parameter with the first control parameter, thereby converting the AD converter. The presence or absence of output abnormality can be diagnosed.

Further, the CPU 101 can use a control parameter transmitted from another electronic control apparatus via a CAN (Controller Area Network) as the second control parameter.
In addition, when multiple sensors that generate analog outputs are provided, the CPU 101 uses, as a first control parameter, a control parameter obtained by converting one analog output of the multiple sensors into a digital signal by an AD converter, A control parameter obtained by converting an analog output of another sensor of the multiple sensors into a digital signal by an AD converter is set as a second control parameter, and the first control parameter and the second control parameter are compared, and AD It is possible to diagnose whether there is an abnormality in the output of the converter.

  DESCRIPTION OF SYMBOLS 100 ... Automotive electronic control apparatus, 101 ... CPU, 102 ... ROM, 103 ... RAM, 104 ... AD converter, 105 ... Pulse input circuit, 106 ... Digital output circuit, 107 ... Pulse output circuit, 201 ... Throttle sensor, 202 DESCRIPTION OF SYMBOLS ... Airflow sensor, 203 ... Crank angle sensor, 204 ... Vehicle speed sensor, 211 ... Relay, 212 ... Fuel injection valve, 213 ... Ignition coil

Claims (2)

An automotive electronic control device including an AD converter that inputs an analog output signal of a sensor and converts it into a digital signal,
The first control parameter detected based on the output of the AD converter and the control parameter obtained from the output of a sensor different from the sensor that detects the first control parameter, and changes in correlation with the first control parameter. A diagnostic means for comparing the second control parameter to detect the presence or absence of output abnormality of the AD converter,
In the diagnostic means, the first control parameter and the second control parameter are state quantities different from each other, and the second control parameter is a control parameter detected based on an output of the AD converter. Control device. An automotive electronic control device including an AD converter that inputs an analog output signal of a sensor and converts it into a digital signal,
The first control parameter detected based on the output of the AD converter and the control parameter obtained from the output of a sensor different from the sensor that detects the first control parameter, and changes in correlation with the first control parameter. A diagnostic means for comparing the second control parameter to detect the presence or absence of output abnormality of the AD converter,
The electronic control device for an automobile, wherein the diagnosis means detects the presence or absence of an output abnormality of the AD converter by comparing the change speed of the first control parameter and the change speed of the second control parameter.