Alternator Torque Ripple Control for Belt Slip Reduction
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Solution Overview
Problem
The alternator in an accessory belt system experiences significant slip and abrasion due to its large inertial force and small pulley, leading to increased driving load and noise, which existing solutions attempt to mitigate with special pulleys like Over-running Alternator Pulley (OAP) and Over-running Alternator Decoupler (OAD), but these are not always effective.
Innovation Solution
A device comprising an alternator with a rotor and stator, a detector to track the rotor's position, and a controller that generates torque ripple opposite to the crankshaft's rotation, synchronizing the crankshaft's cycle with the torque ripple's cycle using signals from the crankshaft, camshaft, spark plug, or fuel injector to reduce belt load and slip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a standard alternator pulley is used, then the alternator structure is simple, but the accessory belt experiences large slip and abrasion due to crankshaft rotation fluctuation
Solution Approach 1:
The patent applies dynamics by making the alternator pulley speed variable rather than fixed. The controller dynamically adjusts the alternator rotation speed to compensate for crankshaft rotation fluctuations, ensuring the pulley speed varies in opposition to the crankshaft fluctuation. This dynamic speed control reduces belt slip and abrasion without requiring a mechanically complex special pulley structure.
Solution Approach 2:
The patent changes the operating parameter of the alternator from fixed speed to variable speed. By controlling the alternator rotation speed to fluctuate in opposite phase to the crankshaft rotation fluctuation, the system reduces the net speed variation at the pulley-belt interface. This parameter change allows using a standard simple pulley while achieving reduced belt wear through intelligent speed modulation.
2Object-affected harmful factors
If special pulleys like OAP or OAD are used, then belt slip and noise are reduced, but the device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical solution (special pulleys with complex internal structures like OAP or OAD) with an electronic control system. Instead of using mechanically complex pulleys designed to absorb or decouple fluctuations, the system uses a controller to electronically regulate the alternator motor speed, substituting mechanical complexity with electronic control to achieve the same noise and slip reduction效果.
Solution Approach 2:
The alternator serves a dual function: it generates electricity while also acting as a speed control mechanism for itself. The controller commands the alternator motor to adjust its own rotation speed in response to detected crankshaft fluctuations, allowing the system to self-regulate without requiring separate mechanical damping devices or complex pulley assemblies.
3Duration of action of stationary object
If the alternator rotation speed is controlled to reduce belt load, then belt durability improves, but the control system complexity increases
Solution Approach 1:
The patent implements feedback control by continuously detecting the crankshaft rotation speed and using this information to adjust the alternator motor speed. The controller receives feedback signals about engine operating conditions and dynamically adjusts the alternator speed accordingly, creating a closed-loop control system that optimizes belt durability while managing complexity through intelligent sensor-based regulation.
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
This solution effectively reduces the load on the accessory belt and improves slip and abrasion at the alternator pulley without the need for special pulleys, thereby enhancing durability and noise reduction.
Implementation Method 1
an alternator including a rotor and a stator... generating a torque ripple with an opposite phase to a rotation of a crankshaft
Data Source
AI summary
A device for ripple controlling an alternator includes an alternator including a rotor and a stator, a detector for detecting a rotation position of the rotor, and a controller for controlling the alternator to generate a toque ripple with an opposite phase to a rotation of a crankshaft of an engine.