Dog-Clutch State Detection Using Speed Sensors and Torque Pulses
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Solution Overview
Problem
Existing vehicle powertrains rely on a fork position sensor for dog-clutch engagement detection, which is costly, bulky, and prone to failure over time, leading to unreliable engagement or disengagement detection.
Innovation Solution
A method and powertrain design that uses first and second speed sensors to measure the rotation speeds of primary and secondary parts, respectively, and applies torque pulses to determine the dog-clutch configuration without a fork position sensor, ensuring reliable detection of engaged or disengaged states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fork position sensor is used to detect dog-clutch engagement, then engagement detection is possible, but the system becomes costly, bulky, and unreliable over time
Solution Approach 1:
The patent removes the fork position sensor from the system entirely. Instead of using a dedicated sensor to detect engagement, the system extracts engagement information from the existing speed sensors that monitor primary and secondary part rotation speeds. This eliminates the problematic sensor while maintaining detection capability through mathematical analysis of speed differential data.
Solution Approach 2:
The patent replaces the mechanical fork position sensor with an electronic/software-based detection method. The controller calculates speed differentials between primary and secondary parts and uses this data to determine engagement state, substituting a mechanical sensing system with an electronic computation approach that is more reliable and less complex.
2Reliability
If a fork position sensor is implemented, then engagement detection is achieved, but space requirements increase and cost increases
Solution Approach 1:
The patent makes the existing speed sensors multi-functional. These sensors originally serve to monitor rotation speeds for powertrain control, and the patent extends their function to also detect dog-clutch engagement status. By analyzing the speed differential between primary and secondary parts, the same sensors provide dual purposes, eliminating the need for additional dedicated sensors and reducing space requirements.
Solution Approach 2:
The patent extracts engagement detection capability from a separate physical sensor and derives it instead from the operational data already collected by the speed sensors. This removes the need for additional sensor mounting space while maintaining accurate detection of engagement states through computational analysis of existing sensor data.
3Loss of time
If torque pulses are applied to detect engagement quickly, then detection speed improves, but passenger comfort may be affected
Solution Approach 1:
The patent applies partial torque modulation rather than full torque pulses. By using small, controlled torque variations that are sufficient to generate detectable speed differential changes but too small to be felt by passengers, the system achieves quick detection without causing discomfort. This partial action approach balances detection effectiveness with passenger comfort.
Solution Approach 2:
The system uses feedback from speed sensors to monitor the effects of torque application on speed differentials. By continuously measuring the response of the primary and secondary parts to torque input, the controller can quickly determine engagement status based on how the system responds, achieving fast detection without needing large disruptive torque pulses that would affect passenger comfort.
Data Source
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AI summary
A method to control a powertrain 7 of a vehicle 1, the powertrain comprising: - a dog-clutch 17, comprising a primary part (19) and a secondary part (21), - a controller (9), wherein the dog-clutch is configured to, upon receiving an order given by the controller, evolve to a desired configuration, between an engaged configuration and a disengaged configuration, - a first speed sensor (20), configured to measure a physical quantity that reflects a rotation speed of the primary part, and - a second speed sensor (22), configured to measure a physical quantity that reflects a rotation speed of the secondary part. The method comprises a step of giving the order to evolve to the desired configuration, the order being given by the controller to the dog-clutch, and a step of checking, by the controller, whether the dog-clutch has actually evolved to the desired configuration.