Crankshaft Positioning via Electrical Machine Torque Control
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Solution Overview
Problem
Existing methods for precisely positioning the crankshaft of a prime mover in vehicles, such as locomotives, are imprecise and require extensive manual operations, and diagnostic procedures for engine performance degradation are also labor-intensive.
Innovation Solution
A system and method utilizing an electrical machine with a processor and sensor to control the prime mover's rotation, generate position and acceleration signals, and compare cylinder compression signals to detect malfunctions, allowing for precise positioning and diagnosis of the crankshaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual barring operations are used to position the crankshaft, then the operation can be performed, but the positioning precision is insufficient and extensive manual labor is required
Solution Approach 1:
The patent replaces the manual mechanical barring operation with an automated electrical system. The electrical machine generates controlled torque to rotate the crankshaft, substituting human physical effort and manual mechanical manipulation with an electromechanical system that provides both automation and precise positioning control through sensor feedback and processor-based control algorithms.
Solution Approach 2:
The patent implements a feedback control system where sensors detect the actual crankshaft position and rotational speed, and this information is fed back to the processor. The processor continuously adjusts the electrical machine's output torque based on the feedback signal, enabling precise positioning by comparing actual position with target position and making real-time corrections.
2Measurement precision
If traditional diagnostic procedures are used for engine performance degradation, then diagnosis can be performed, but extensive manual operations and time are required
Solution Approach 1:
The system enables self-diagnosis of engine conditions by automatically monitoring crankshaft rotation characteristics and cylinder compression through the electrical machine's operation. The processor analyzes the generated position and acceleration signals to identify compression variations in different cylinders, allowing the engine to be diagnosed without requiring external manual testing equipment or procedures.
Solution Approach 2:
The patent replaces traditional manual compression testing equipment and procedures with the electrical machine's own sensing and control system. Instead of using separate diagnostic tools to measure cylinder compression, the system uses the electrical machine's position and acceleration sensors to infer compression levels during normal operation, eliminating the need for manual disassembly and testing.
3Extent of automation
If the electrical machine is used for cranking operation, then automation is achieved, but the positioning precision is insufficient to replace manual barring operations
Solution Approach 1:
The patent employs dynamic control of the electrical machine during cranking operation. Rather than simple on/off control, the system continuously adjusts the torque output based on real-time feedback from position sensors. The processor modulates the electrical machine's operation to account for varying mechanical resistance, inertia, and friction, enabling both automation and precise positioning by adapting the control parameters dynamically throughout the cranking process.
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 precise positioning of the crankshaft and efficient diagnosis of engine performance issues, reducing manual labor and improving maintenance efficiency.
Implementation Method 1
cranking the prime mover at a controlled rate by supplying current to the machine
Implementation Method 2
a sensor generating a position signal representing an angular position of the rotor
Data Source
AI summary
Apparatus for controlling and diagnosing a prime mover of a vehicle traction system includes an alternator having a rotor and coupled to a crankshaft of the prime mover, a source of electrical energy, a position sensor supplying a position signal representative of an angular position of the rotor, and a control computer. The computer supplies energy to the alternator to crank the prime mover at a controlled rate. In a diagnosis mode, the computer generates a condition signal indicative of a malfunction of the prime mover, from a compression signal derived from an acceleration signal which is derived from the position signal. In a barring-over mode, the computer also supplies energy to the alternator and monitors the position signal to place the crankshaft in a desired angular position in an operation separate from diagnosis mode.