Hybrid Powertrain Torque Prioritization for Drivability
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Solution Overview
Problem
In hybrid powertrain systems, managing simultaneous input torques from internal combustion engines and electric machines to prevent abrupt changes in vehicle acceleration, known as 'jerk,' is challenging due to differing reaction times, leading to adverse effects on drivability.
Innovation Solution
A method that prioritizes input acceleration and output torque based on whether the powertrain is in transient or stable operation, using a lead period to coordinate torque requests between the engine and electric machines, ensuring simultaneous changes in input torque to maintain smooth vehicle acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If simultaneous input torques from internal combustion engine and electric machine are managed without coordination, then individual torque responses are achieved, but abrupt changes in vehicle acceleration (jerk) occur due to different reaction times
Solution Approach 1:
The control system introduces a lead period that anticipates the difference in reaction times between the internal combustion engine and electric machine. By preemptively adjusting torque requests to account for the engine's slower response, the system coordinates torque delivery from both sources to occur simultaneously, eliminating abrupt acceleration changes and improving drivability
2Ease of operation
If torque requests are adjusted to account for different reaction times, then coordinated torque delivery is achieved, but control system complexity increases
Solution Approach 1:
The control system introduces a lead period that anticipates the difference in reaction times between the internal combustion engine and electric machine. By preemptively adjusting torque requests to account for the engine's slower response, the system coordinates torque delivery from both sources to occur simultaneously, eliminating abrupt acceleration changes and improving drivability
Data Source
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AI summary
A powertrain includes an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member. A method for controlling the powertrain includes operating the transmission in an operating range state wherein input speed can operate independent of output speed and wherein a reactive torque is transmitted through the transmission. The method further includes monitoring commands affecting a requested output torque, monitoring a calculated output torque, and prioritizing between an input acceleration of the transmission and an output torque of the transmission based upon whether operating the transmission in the operating range state is in transient operation or stable operation.