Electric Throttle Sensor Abnormality Detection Cost Reduction
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Solution Overview
Problem
The high cost of electric throttles is attributed to the need for two rotation angle sensors to detect abnormalities, which can be reduced by using a pressure sensor to replace one of the sensors.
Innovation Solution
An electric throttle design that incorporates a downstream pressure sensor to determine sensor abnormalities, allowing for the reduction of one rotation angle sensor and incorporating a motor, throttle body, and ECU for feedback control to match the actual throttle opening angle with a target angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two rotation angle sensors are used to detect abnormality, then the reliability of abnormality detection is improved, but the cost of the electric throttle increases
Solution Approach 1:
The downstream pressure sensor, originally intended for detecting intake pressure, is made to serve a dual function by also detecting throttle valve opening angle abnormalities. The abnormal-sensor determining portion analyzes the relationship between pressure sensor readings and throttle valve position to identify sensor failures, thereby eliminating the need for a dedicated second rotation angle sensor while maintaining abnormality detection reliability
Solution Approach 2:
The abnormal-sensor determining portion acts as an intermediary that indirectly detects rotation angle sensor abnormalities by analyzing the correlation between downstream pressure sensor data and throttle valve opening angle data. This intermediary approach allows one sensor to detect abnormalities of another sensor without requiring direct redundancy
2Measurement precision
If two rotation angle sensors are used to detect abnormality, then the measurement precision of throttle valve position monitoring is improved, but the device complexity increases
Solution Approach 1:
The downstream pressure sensor is designed to perform its primary function of pressure detection while simultaneously serving as an indirect monitor for throttle valve opening angle abnormalities. The abnormal-sensor determining portion processes the pressure sensor output in conjunction with throttle valve position data to maintain monitoring precision without adding a second rotation angle sensor
Solution Approach 2:
The patent replaces a mechanical redundancy approach (using two rotation angle sensors) with a sensor fusion approach that uses the existing downstream pressure sensor in combination with the abnormal-sensor determining portion. This substitution reduces device complexity by eliminating redundant mechanical sensors while maintaining monitoring precision through computational analysis
Data Source
AI summary
An ECU loads detected values of a rotation angle sensor and a pressure sensor which are mounted to an electric throttle, and executes an abnormal-sensor determination control to determine whether one of the rotation angle sensor and the pressure sensor is abnormal. Specifically, the ECU determines that one of the rotation angle sensor and the pressure sensor is abnormal, in a case where a state that a tendency of the actual opening angle detected by the rotation angle sensor does not match a tendency of the pressure detected by the downstream pressure sensor has continued for a period greater than or equal to a predetermined period. Therefore, since the pressure sensor can replace the rotation angle sensor used for detecting abnormality in a conventional technology, two rotation angle sensors can be reduced to one rotation angle sensor, and a cost is reduced.