Engine Control Method for Reverse Rotation Protection
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Solution Overview
Problem
Internal combustion engines face significant damage risks during temporary reversal of rotation, particularly when combustion occurs in a cylinder, which existing methods struggle to detect reliably without causing unnecessary inhibition of combustion.
Innovation Solution
An engine control method that predicts engine speed at specific angular positions, using two thresholds to determine whether to inhibit or allow combustion, with a second prediction made closer to top dead center to enhance reliability and minimize false detections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a predetermined threshold is set at a high value to improve reliability of reversal detection, then the reliability of detecting rotation reversal is improved, but the number of false detections increases leading to unnecessary inhibition of combustion
Solution Approach 1:
The detection process is segmented into two distinct stages: a first prediction of engine speed made at an first angular position, and a second prediction made at a second angular position that is subsequent to the first. This segmentation allows the system to perform an initial assessment and then a confirmatory assessment, reducing false detections while maintaining reliable reversal detection.
Solution Approach 2:
The first prediction of engine speed is made in advance at a first angular position before the second angular position. This preliminary action allows the system to prepare for potential reversal detection and then confirm it with a second prediction, rather than making a single high-threshold decision that causes false positives.
2Productivity
If a predetermined threshold is set at a low value to reduce false detections, then unnecessary inhibition of combustion is reduced, but the reliability of detecting rotation reversal deteriorates
Solution Approach 1:
The system uses feedback from the first prediction to trigger a second prediction. When the first prediction indicates a potential reversal (speed below threshold), the system responds by making a second prediction at a subsequent angular position to confirm whether reversal actually occurs. This feedback mechanism ensures that combustion is inhibited only when reversal is confirmed, not merely suspected.
Solution Approach 2:
The dual prediction system serves itself by using the outcome of the first prediction to determine whether a second prediction is necessary. This self-regulating mechanism ensures that the more computationally intensive second prediction is performed only when needed, balancing reliability with computational efficiency.
3Device complexity
If a single prediction of engine speed is made to simplify the control method, then the device complexity is reduced, but the reliability of reversal detection and reduction of false detections is compromised
Solution Approach 1:
The control method dynamically adjusts the detection process based on the first prediction results. When the first prediction shows engine speed above the threshold, no second prediction is made, simplifying the process. When the first prediction shows speed below the threshold, a second prediction is triggered, enhancing reliability. This dynamic approach adapts the complexity of the detection process to the actual risk level.
Data Source
AI summary
Engine control method for protecting the engine during reverse rotation, and involving the following steps: when a first prediction of the engine speed at a next top dead center is below a predetermined lower threshold, inhibiting the next combustion for this cylinder of the engine, and when the first prediction of the engine speed is between the predetermined lower threshold and a predetermined upper threshold, and the engine reaches a second measurement predetermined angular position which is subsequent to the first measurement position, activating the prediction means again in order to obtain a second prediction of the engine speed at the next top dead center.