Opposed Piston Engine Rotation Direction Control
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Solution Overview
Problem
Conventional opposed piston engine position sensors cannot determine the rotation direction of crankshafts, which is crucial for stop-start applications and engine diagnostics, leading to a need for a system and method to sense and control rotation direction.
Innovation Solution
A sensor assembly with Hall-Effect sensors is mounted near the crankshaft wheel to detect the presence and absence of teeth, generating an output signal with characteristics that indicate the direction of rotation, allowing a controller to compare and correct any deviation from the correct rotation direction by controlling fuel injection, air flow, transmission, and engine operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional engine position sensors are used, then the position and speed of crankshafts can be estimated, but the direction of rotation cannot be determined
Solution Approach 1:
The patent replaces conventional mechanical position sensors with a magnetic field-based sensing system using Hall-Effect sensors. This substitution enables detection of rotation direction by sensing magnetic field changes caused by teeth on the crankshaft wheel, thereby recovering the rotation direction information that was previously lost.
Solution Approach 2:
The patent changes the measurement parameter from simple position detection to magnetic field strength detection. By monitoring changes in magnetic field strength as teeth pass by the Hall-Effect sensors, the system can determine both position and rotation direction, thus improving measurement precision while preventing information loss.
2Adaptability or versatility
If rotation direction detection is added to improve engine control, then stop-start applications and diagnostics are enhanced, but device complexity increases
Solution Approach 1:
The patent divides the sensing function into multiple discrete Hall-Effect sensors positioned at different locations. Each sensor independently detects magnetic field changes, and the controller processes signals from multiple sensors to determine rotation direction. This segmentation enables enhanced adaptability for stop-start applications while managing device complexity through modular sensor placement.
Solution Approach 2:
The Hall-Effect sensor assembly serves multiple functions: it detects crankshaft position, determines rotation direction, and provides data for both stop-start control and engine diagnostics. This multi-functionality enhances adaptability across different applications without proportionally increasing device complexity, as the same sensor hardware supports multiple control strategies.
3Reliability
If corrective action is taken for wrong rotation direction, then engine operation is protected, but fuel injection and air flow control are disrupted
Solution Approach 1:
The controller applies preliminary anti-action by detecting wrong rotation direction before significant engine damage can occur. When reverse rotation is detected, the controller proactively inhibits fuel injection and adjusts air flow to prevent harmful operation, thereby protecting engine reliability while minimizing disruption to fuel injection and air flow control by addressing the issue at its earliest stage.
Solution Approach 2:
The system implements feedback control by continuously monitoring rotation direction and adjusting fuel injection and air flow based on the detected direction. When correct rotation direction is confirmed, normal fuel injection and air flow control are maintained, ensuring productivity. When wrong direction is detected, corrective feedback actions are taken to protect reliability, thus balancing both concerns through continuous feedback-based adjustment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate determination and correction of crankshaft rotation direction, ensuring proper engine operation, including fuel management, braking, and restart conditions, thereby enhancing engine diagnostics and efficiency.
Implementation Method 1
A sensor assembly with Hall-Effect sensors is mounted near the crankshaft wheel to detect the presence and absence of teeth
Data Source
AI summary
A method for controlling operation of an opposed piston engine is provided, comprising: determining a direction of rotation of the engine; comparing the determined direction of rotation to a correct direction of rotation of the engine; and responding to the determined direction of rotation being different from the correct direction of rotation by taking corrective action.