Hybrid Powertrain Torque Direction Control via Speed Threshold
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Solution Overview
Problem
Existing hybrid powertrain systems face challenges in efficiently managing torque direction changes, particularly when the vehicle speed exceeds a certain threshold, which can lead to unsafe or uncomfortable transitions between forward and reverse motions.
Innovation Solution
A control system for hybrid powertrain systems that monitors operator torque requests, rotational direction, and speed, allowing changes in torque direction only when the output member speed is below a predetermined threshold, and inhibiting such changes when the speed exceeds this threshold to ensure safe and comfortable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the system allows torque direction changes at high speeds, then the vehicle can respond quickly to operator requests, but unsafe or uncomfortable transitions between forward and reverse motions occur
Solution Approach 1:
The control system changes the parameter of torque direction changeability based on the speed parameter. When vehicle speed exceeds the predetermined threshold, the system prohibits torque direction changes regardless of operator requests. When speed is below the threshold, the system allows torque direction changes. This dynamic parameter adjustment resolves the contradiction by adapting system behavior to operating conditions.
2Adaptability or versatility
If the system allows torque direction changes when speed exceeds the threshold, then operational flexibility is improved, but shift shock and discomfort increase
Solution Approach 1:
The control system takes preliminary action by detecting the speed parameter before a torque direction change is requested. When the speed exceeds the predetermined threshold, the system preemptively prohibits torque direction changes to prevent shift shock and discomfort before they can occur. This anticipatory control prevents the harmful effect rather than reacting to it after occurrence.
3Reliability
If the system inhibits torque direction changes below the threshold, then safety is improved, but operational responsiveness deteriorates
Solution Approach 1:
The control system dynamically adjusts its behavior based on real-time speed conditions. The prohibition on torque direction changes is not fixed but varies with the speed parameter. Below the predetermined threshold, the system transitions from a restrictive state to a permissive state, allowing torque direction changes. This dynamic adaptation ensures safety when needed while maintaining operational responsiveness when safe.
Data Source
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AI summary
A hybrid powertrain system includes torque generative devices (14,56,72) to transfer power to an output member (64). An operator torque request, a rotational direction and speed of the output member (64), and a signal output from a transmission range selector are monitored. When a change in a direction of intended motion is determined, the powertrain system can change rotational direction of the output member (64) when the speed of the output member is less than a threshold. The powertrain can inhibit a change in the rotational direction of the output member.