Vehicle Engine Abnormality Detection Using Dynamic Torque Thresholds
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Solution Overview
Problem
Conventional abnormality determination devices in vehicles often excessively suppress or disproportionately determine engine output abnormalities, leading to inaccurate assessments based on the set engine operation state conditions.
Innovation Solution
An abnormality determination device that estimates the actual torque output by the engine using the torque of a first motor and determines an output abnormality when the estimated torque falls below a target torque's allowable range, while also considering a threshold value for rotational speed increment to prevent misdetermination, with the threshold value increasing as the target torque rises.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed threshold value is used for determining engine output abnormality, then the determination process is simple, but misdetermination occurs excessively during high torque output and low torque output conditions
Solution Approach 1:
The patent applies the dynamics principle by making the threshold value variable rather than fixed. The threshold is dynamically adjusted based on the target torque value, with higher thresholds for high torque conditions and lower thresholds for low torque conditions. This resolves the contradiction by adapting the determination criterion to operating conditions, improving accuracy without excessive complexity through a systematic adjustment rule.
Solution Approach 2:
The patent applies parameter changes by modifying the threshold value parameter according to the target torque parameter. When target torque is high, the threshold is set higher to prevent excessive suppression of abnormality determination. When target torque is low, the threshold is set lower to prevent disproportionate determination. This parameter adjustment strategy resolves the contradiction between simple fixed-threshold processing and accurate condition-specific determination.
2Reliability
If the threshold value for rotational speed increment is set high, then misdetermination during high torque output is suppressed, but abnormality determination is excessively suppressed during normal operation
Solution Approach 1:
The patent applies parameter changes by adjusting the threshold value parameter based on the target torque parameter. During high torque output, a higher threshold prevents misdetermination while maintaining reliability. During normal low torque operation, a lower threshold ensures abnormality determination remains responsive. This dynamic parameter adjustment resolves the contradiction between reliability during high torque and productivity during normal operation.
Solution Approach 2:
The patent applies local quality by applying different threshold values for different operating conditions (high torque vs. low torque). Instead of a uniform threshold, the system uses condition-specific thresholds that are locally optimized for each operating regime, resolving the contradiction between suppressing misdetermination in high torque conditions and maintaining determination responsiveness in normal conditions.
3Productivity
If the threshold value is set low, then abnormality determination is responsive during low torque output, but misdetermination occurs frequently during high torque output
Solution Approach 1:
The patent applies parameter changes by making the threshold value dependent on the target torque value. When target torque is low, the threshold is set low to maintain responsive abnormality determination. When target torque is high, the threshold is set high to suppress misdetermination. This parameter adjustment strategy resolves the contradiction between responsiveness during low torque and reliability during high torque.
Data Source
AI summary
Provided is an abnormality determination device of a vehicle including an engine and a first motor that is configured to output a torque to an output shaft of the engine, the abnormality determination device determining an output abnormality of dropping output of the engine in the vehicle. The abnormality determination device has an abnormality determination unit that determines that an output abnormality of the engine has occurred when an actual torque that is estimated, based on a torque of the first motor, as a torque actually output from the engine falls below a lower limit of an allowable range for a target torque to be output from the engine, and when an amount of increase in a rotational speed of the engine is smaller than a threshold value for misdetermination suppression, which is a threshold value that is larger as the target torque is higher.