Transmission Node Speed Calculation for Low-Speed Clutch Control
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Solution Overview
Problem
Hydraulic clutches in vehicle transmissions are inefficient, converting much energy into thermal energy and requiring constant pressure, which is not suitable for battery-powered vehicles, and digital clutches require precise control to function properly.
Innovation Solution
A method that calculates the rotational speed of nodes in a transmission by sensing and comparing rotational speeds to a threshold, using calculated speeds when sensed speeds are below the threshold, ensuring proper transition and reducing energy waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If hydraulic clutches are used for gear shifting, then the transmission can change gear ratios, but much energy is converted into thermal energy and dissipated, and constant pressure is required which further expends energy
Solution Approach 1:
The patent replaces hydraulic clutches with digital clutches that use electromagnetic actuators instead of hydraulic pressure. This substitution eliminates the need for constant hydraulic pressure and significantly reduces energy conversion to thermal energy, directly addressing the energy efficiency problem while maintaining the gear ratio changing function.
Solution Approach 2:
The patent changes the operating parameters of the clutch system by using digital control with precise position feedback. Instead of maintaining constant hydraulic pressure, the system uses controlled electromagnetic actuation with position thresholds, reducing energy consumption while achieving the same mechanical function of engaging and disengaging clutch plates.
2Loss of energy
If digital clutches are used to reduce energy loss, then energy efficiency improves, but precise control is required to prevent transmission damage
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the position of the digital clutch actuator and compares it to predetermined thresholds. This feedback mechanism ensures precise control of the clutch engagement and disengagement, preventing transmission damage while maintaining energy efficiency. The controller adjusts the actuator position based on real-time position data.
Solution Approach 2:
The patent establishes predetermined position thresholds that define the engagement and disengagement states of the digital clutch before operation begins. These preliminary设定的 thresholds guide the control system to maintain the clutch within safe operating parameters, preventing damage before it can occur while enabling energy-efficient operation.
3Ease of operation
If sensed rotational speed is used for digital clutch control, then the control system can operate, but when rotational speed is below threshold the control becomes inaccurate
Solution Approach 1:
The patent introduces an intermediary calculation method that uses the relationship between multiple clutch plates and gear ratios to determine the rotational speed of the third clutch plate. When direct sensing is unreliable (below threshold), the system calculates the speed based on measured speeds of other components and the known mechanical relationship, maintaining control accuracy without requiring direct sensing at all conditions.
Data Source
AI summary
A method calculates a rotational speed of a node of a linkage in a transmission allows the continued operation of the transmission even when rotational speeds are difficult to sense due to the lack of rotational speed. The method begins by sensing rotational speed at each node to define a sensed rotational speed for each node. The sensed rotational speed at each node is compared to a threshold rotational speed. The sensed rotational speed continues to be used if an absolute value of the sensed rotational speed of the node is greater than the threshold rotational speed. A calculated rotational speed is calculated when the sensed rotational speed is less than the threshold rotational speed. The sensed rotational speed value is replaced with the calculated rotational speed for the node when the sensed rotational speed is less than the threshold rotational speed.