Rotary Engine Control Device Backward Rotation Prevention
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Solution Overview
Problem
Rotary engines face damage and misjudgment issues due to backward rotation, which can cause the side seal to interfere with the intake port, leading to reduced fuel efficiency and emission performance, and existing detection methods are prone to misjudgment, especially when the shaft rotates by a small angle or for a short time.
Innovation Solution
A control device for a rotary engine that includes a motor mechanically connected to the shaft, a controller for energization control, and a sensor to detect the rotation direction, which stops energization when the shaft rotates a predetermined angle and continues to rotate backward for a predetermined time, avoiding misjudgment by combining rotation angle and time parameters to determine backward rotation and prevent interference with the intake port.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the backward rotation is detected by monitoring small angle and/or short time rotation, then the response speed is improved, but the measurement precision deteriorates due to misjudgment
Solution Approach 1:
The patent changes the detection parameters from monitoring small angles and short durations to monitoring larger angles (180 degrees or more) and longer durations. This parameter transformation resolves the contradiction by ensuring that genuine backward rotation events are captured with sufficient margin to avoid misjudgment while still providing timely detection for prevention purposes.
2Reliability
If the shaft rotation angle threshold is set low for early detection, then the prevention capability is improved, but the reliability deteriorates due to vibration misjudgment
Solution Approach 1:
The system performs preliminary detection of rotation direction and magnitude before the harmful interference occurs. By detecting backward rotation of 180 degrees or more and continuing monitoring for a predetermined time, the system identifies genuine backward rotation events in advance, allowing preventive action to be taken before the side seal damages the intake port.
Solution Approach 2:
The controller continuously receives feedback from the rotation sensor and adjusts its determination based on cumulative rotation angle and duration. The feedback mechanism distinguishes between temporary vibrations (insufficient angle/time) and genuine backward rotation (sufficient angle and time), thereby maintaining both reliability and prevention capability.
3Measurement precision
If the backward rotation detection threshold is set high to avoid misjudgment, then the measurement precision is improved, but the response time increases
Solution Approach 1:
The system maintains continuous monitoring of the shaft rotation from the start of engine operation. By continuously tracking the cumulative rotation angle and duration without interruption, the system can immediately identify when the threshold of 180 degrees plus predetermined time is reached, ensuring both high precision and minimal response time loss.
Data Source
AI summary
A control device prevents damage due to backward rotation of a rotary engine and prevents misjudgment of backward rotation of the rotary engine. The control device for a rotary engine includes a motor mechanically connected to the shaft of the rotary engine, a controller (a motor ECU) that performs energization control of the motor to start the rotary engine by driving the motor, and a sensor (such as a motor rotation sensor). When starting the rotary engine, the controller stops energization to the motor based on an electric signal from the sensor when the shaft of the rotary engine rotates backward a predetermined angle or more, and then the shaft of the rotary engine continues to rotate backward for a predetermined time.