ETM Crankshaft Starting Control for Lightweight Engine Start
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Solution Overview
Problem
Existing internal combustion engine starting systems, particularly in small vehicles like snowmobiles, face challenges due to the weight and inefficiency of electric starting systems, as well as the need for larger motor-generator units to provide sufficient torque and the lack of effective voltage control during starting and generating operations.
Innovation Solution
A system and method utilizing an electric turning machine (ETM) connected to the crankshaft, with a controller determining the absolute angular position of the crankshaft to deliver specific torque levels for starting, allowing for a smaller and lighter power source, and implementing vector control for efficient power delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an electric starting system with battery and starter is used, then the engine can be started conveniently, but the vehicle weight increases and fuel efficiency decreases
Solution Approach 1:
The patent combines the starter motor and generator into a single motor-generator unit that can function in both modes. This merging eliminates the need for separate starter and generator components, reducing overall system weight while maintaining both starting and power generation capabilities.
Solution Approach 2:
The motor-generator unit is designed to perform multiple functions: it acts as a starter motor when high torque is needed to crank the engine, and as a generator when the engine is running to recharge the battery and power electrical loads. This multi-functionality eliminates redundant components and reduces vehicle weight.
2Weight of moving object
If a motor-generator unit is used to replace separate starter and generator, then system complexity and weight are reduced, but sufficient torque for starting becomes difficult to achieve
Solution Approach 1:
The control system dynamically adjusts the operating parameters of the motor-generator unit based on real-time conditions. During engine starting, the controller optimizes the torque output by adjusting current magnitude and phase angle, enabling the unit to deliver maximum required torque despite its reduced size compared to traditional separate systems.
Solution Approach 2:
The patent employs vector control to dynamically change electrical parameters (current magnitude, phase angle, frequency) of the motor-generator unit. This allows precise control of torque output, enabling a smaller, lighter unit to deliver sufficient starting torque by optimizing parameter combinations during the cranking phase.
3Manufacturing precision
If vector control is implemented for the motor-generator, then torque control precision is improved, but control system complexity increases
Solution Approach 1:
The patent replaces complex mechanical torque control mechanisms with electronic vector control. By using electronic sensors and controllers to adjust electrical parameters, the system achieves precise torque control without the mechanical complexity of traditional torque adjustment mechanisms, ultimately reducing overall system complexity.
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 lightweight electrical starting of internal combustion engines with precise torque control, reducing the duration of the starting sequence and improving the control of motor-generator operations, thereby enhancing fuel efficiency and handling.
Implementation Method 1
an electric turning machine (ETM) operatively connected to the crankshaft... Electric power is delivered to the ETM to rotate the crankshaft
Implementation Method 2
an electrical generator operatively connected to the crankshaft of the engine. As the crankshaft turns the rotor of the electrical generator, the generator generates electricity
Data Source
AI summary
A method for controlling delivery of electric power between a power source and an electric turning machine (ETM) comprises applying a start signal to a start-up power electronic switch to cause turning on of the start-up power electronic switch and to allow delivery of electric power from the power source to the ETM via the start-up power electronic switch. A recharge signal is applied to a run-time power electronic switch to cause turning on of the run-time power electronic switch for delivery of electric power from the ETM to the power source via the run-time power electronic switch. A circuit comprises a discharging circuit including the start-up power electronic switch for delivering the electric power when the start-up power electronic switch is turned on. A charging circuit includes the run-time power electronic switch for delivering the electric power when the run-time power electronic switch is turned on.