JP2020191358A5 - - Google Patents

Claims (12)

An electronic control device equipped with a diagnostic unit that detects a decrease in fan rotation speed from the output of the fan via a low-pass filter . The electronic control device according to claim 1, wherein the low-pass filter has a cutoff frequency which is a frequency characteristic according to a determination rotation speed, and smoothes a signal having a frequency equal to or higher than the determination frequency. The diagnostic unit is provided in a control microcomputer having a function of capturing a filter output signal as a voltage value.
The electronic control device according to claim 2, wherein the diagnostic unit diagnoses a rotation speed abnormality when the voltage value exceeds a predetermined value inside the microcomputer. The electronic control device according to claim 3, wherein the low-pass filter is digitally processed by the control microcomputer. The electronic control device according to claim 3, wherein the low-pass filter is configured by connecting a plurality of filters having different frequency characteristics in parallel and connected to the control microcomputer. A comparator circuit connected to the output of the low-pass filter is provided.
The electronic control device according to claim 1, wherein the comparator circuit compares a voltage corresponding to a specified value and inputs a comparator output to a control microcomputer. Equipped with an outside world recognition microcomputer that performs arithmetic processing based on the signal of the outside world information sensor of the vehicle.
The electronic control device according to any one of claims 1 to 6, wherein the fan is attached so as to cool the external recognition microcomputer. The electronic control device according to claim 7, wherein the outside world recognition microcomputer transmits a signal indicating that the fan has an abnormal rotation speed to a backup microcomputer when the voltage value of the output exceeds a predetermined value. By controlling the rotation speed of the fan from the control microcomputer, the rotation speed according to the rotation speed control can be set as the determination frequency.
The electronic control device according to claim 4, wherein the rotation speed of the fan can be controlled / monitored by the calorific value. A control microcomputer that functions as the diagnostic unit, and
The fan having a sensor that outputs a pulse signal according to the rotation of the fan, and the fan.
The low-pass filter into which a pulse signal is input from the sensor is provided.
The control microcomputer is
The electronic control device according to claim 1, wherein when the digital value of the signal output from the low-pass filter falls below the threshold value, it is determined that the rotation speed of the fan has decreased. A control microcomputer that functions as the diagnostic unit, and
The fan having a sensor that outputs a pulse signal according to the rotation of the fan, and the fan.
The low-pass filter to which a pulse signal is input from the sensor, and
A comparator circuit that compares the voltage value of the signal output from the low-pass filter with the threshold voltage is provided.
The control microcomputer is
The electronic control device according to claim 1, wherein a decrease in the rotation speed of the fan is detected from a signal output from the comparator circuit. A control microcomputer that functions as the diagnostic unit, and
The fan having a sensor that outputs a pulse signal according to the rotation of the fan, and the fan.
A pulse signal is input from the sensor, and a first low-pass filter having a first cutoff frequency and a first low-pass filter,
A second low-pass filter, to which a pulse signal is input from the sensor and has a second cutoff frequency higher than the first cutoff frequency, is provided.
The control microcomputer is
When the value indicated by the signal output from the first low-pass filter falls below the first threshold value, the function of the control microcomputer is taken over by another control microcomputer.
The value indicated by the signal output from the first low-pass filter exceeds the first threshold value, and the value indicated by the signal output from the second low-pass filter sets the second threshold value. The electronic control device according to claim 1, wherein if the value is lower than the limit, the calculation amount of the control microcomputer is reduced.