Engine Restart Control Using Motor Current to Detect Piston Position
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Solution Overview
Problem
Existing Start and Stop engine systems for single-cylinder engines face challenges in efficiently restarting the engine due to the distance between adjacent compression steps, requiring complex sensor setups and additional components, which can lead to inaccurate re-start timing and increased startup time.
Innovation Solution
A re-start process using a simple speed sensor on the crankshaft, where the electric motor control unit determines the starting and ending positions of inverse rotations based on piston stall conditions and maximum rotation angles, eliminating the need for additional sensors and optimizing torque and size, allowing for guaranteed engine re-start with reduced computational burden.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional sensors are installed to detect piston position and compression step, then re-start timing accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The system uses the electric motor's own operational characteristics (current consumption, rotation speed) to indirectly detect piston position and compression step, eliminating the need for separate sensors. The motor essentially monitors its own state to determine when re-start is appropriate.
Solution Approach 2:
The patent replaces mechanical/sensor-based position detection with an electrical/control-based approach, using the EMU to monitor motor current and rotation characteristics to infer piston position, thereby substituting physical sensors with electrical measurement and computation.
2Reliability
If complex sensor setups are used to detect compression step, then re-start reliability is improved, but computational burden and system complexity increase
Solution Approach 1:
The electric motor control unit monitors its own operational parameters (current, rotation speed) to determine piston position and compression step, eliminating the need for external sensors and reducing computational complexity while maintaining reliable re-start functionality.
Solution Approach 2:
The patent extracts the essential detection function from complex sensor systems and implements it through simplified monitoring of the motor's own operational characteristics, removing unnecessary components while preserving the core functionality of reliable re-start detection.
3Ease of operation
If inverse rotation is performed for pre-established angle or time, then re-start procedure is simplified, but re-start timing accuracy deteriorates
Solution Approach 1:
The patent implements dynamic adjustment of the inverse rotation angle based on real-time monitoring of motor current and rotation characteristics, allowing the system to adapt to varying engine conditions while maintaining both procedural simplicity and timing accuracy through continuous feedback control.
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 efficient and reliable engine re-starts with optimized electric motor performance, reducing the need for complex sensor connections and computation power, while minimizing time waste and ensuring smooth engine reactivation without complete shutdown procedures.
Implementation Method 1
using an electric motor acting on the crankshaft of the internal combustion engine
Implementation Method 2
the kinetic energy which is accumulated during the forward rotation allows overcoming the nearer compression step
Data Source
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AI summary
A process for managing the re-start of an internal combustion engine in a Start and Stop system using an electric motor managed by an electric motor control unit (EMU), a first step of direct evaluation of the rotation regime of the crankshaft being provided by an internal combustion engine control unit (ECU) through a sensor put on the crankshaft: if the rotation regime is above a threshold corresponding to the sensor accuracy loss, in case of re-opening of the throttle valve said control unit of the combustion engine (ECU) continues to provide fuel and ignition; otherwise a crankshaft positioning step is provided by the electric motor control unit (EMU) comprising: a forward crankshaft rotation by a predetermined forward rotation angle; a detection of a possible piston stall state followed, in negative case, by an additional forward crankshaft rotation until reaching a maximum predetermined forward rotation angle; an inverse crankshaft rotation by a predetermined angle; and a detection of a possible piston stall state followed, in negative case, by an additional inverse crankshaft rotation until reaching a maximum predetermined inverse rotation angle.