Bidirectional Engine Position Sensor for Hybrid Electric Motor Control
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Solution Overview
Problem
Hybrid electric motor systems face challenges in accurately determining and controlling engine position during startup, low-speed operations, and shutdown, leading to inefficiencies and increased costs due to the reliance on dedicated sensors and potential inaccuracies in accounting for rotation directions.
Innovation Solution
A system comprising a bidirectional engine position sensor, a controller, and non-transitory memory that estimates and stores engine component positions during shutdown and restart, allowing for precise control of the electric motor using sensor-based and sensorless methods, reducing the need for dedicated encoders and resolvers, and optimizing engine position for efficient startup and shutdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a bidirectional engine position sensor is used to minimize restart delay, then engine restart speed is improved, but fuel consumption increases due to higher crankshaft fueling rates
Solution Approach 1:
The system performs preliminary action by storing the engine component position at shutdown in memory before restart occurs. This allows the controller to immediately determine the starting position and begin fueling without delay, achieving fast restart without requiring high fueling rates throughout the entire crankshaft rotation sequence.
Solution Approach 2:
The patent replaces the traditional mechanical sensor-based position detection system with an estimation algorithm that calculates engine component position based on stored shutdown position and crankshaft revolutions. This substitution eliminates the need for continuous sensor input during restart, reducing the reliance on mechanical sensing systems.
2Measurement precision
If dedicated encoders and resolvers are used for sensor-based control, then electric motor position accuracy is improved, but system cost and complexity increase
Solution Approach 1:
The system extracts only the essential position information needed for control by storing the engine component position at shutdown in memory. This extracted position data, combined with crankshaft revolution counting, provides sufficient accuracy for electric motor control without requiring complex dedicated encoder or resolver systems.
Solution Approach 2:
Instead of using physical sensors to continuously measure position, the system creates a digital copy of the position information by storing the shutdown position in memory and calculating subsequent positions based on crankshaft revolutions. This virtual position tracking achieves the necessary accuracy without physical sensing hardware.
3Device complexity
If traditional position determination methods are used during shutdown, then system simplicity is maintained, but position accuracy decreases due to failure to account for positive and negative rotation
Solution Approach 1:
The system implements dynamic position tracking by using a bidirectional engine position sensor that accurately captures position changes during both positive and negative rotation. The controller dynamically updates the stored position based on the actual rotation direction, maintaining accuracy throughout the shutdown process regardless of rotation variations.
Data Source
AI summary
System comprising an internal combustion engine including a crankshaft, a crankshaft sprocket coupled to the crankshaft, an electric motor in mechanical communication with the crankshaft sprocket, a bidirectional engine position sensor coupled to the crankshaft sprocket, a controller in electrical communication with the bidirectional engine position sensor and a non-transitory memory having instructions that, in response to execution by a processor, cause the processor to determine a position of an engine component upon shutdown of the engine, store the position of the engine component at shutdown in the non-transitory memory, and control the electric motor at restart in response to the position of the engine component at shutdown are disclosed. Methods are also disclosed.