Hybrid Vehicle Traction Machine Coupling Control
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Solution Overview
Problem
Existing methods for controlling the coupling and decoupling of traction machines in hybrid vehicles often result in permanent coupling, leading to energy losses and increased consumption due to torque machine losses, especially at high speeds.
Innovation Solution
A method that determines when the torque setpoint for a wheel set is below or above predetermined thresholds, calculating specific parameters to authorize coupling or decoupling, thereby optimizing energy recovery and minimizing loss torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the traction machine is permanently coupled to the wheel set, then the vehicle maintains traction capability and responds quickly to acceleration requests, but energy losses increase due to torque machine losses especially at high speeds
Solution Approach 1:
The patent applies dynamics by transitioning the coupling state from static (permanent) to dynamic (variable). The traction machine is coupled or decoupled based on real-time operating conditions, specifically when the vehicle speed exceeds a threshold value and remains stable for a predetermined duration. This dynamic adjustment allows the system to maintain traction capability when needed while eliminating energy losses during high-speed stable cruising, directly resolving the contradiction between maintaining speed capability and reducing energy losses.
Solution Approach 2:
The patent changes the operational parameters by introducing speed threshold values and time duration criteria as decision parameters for coupling/decoupling. Instead of maintaining a fixed coupling state, the system monitors vehicle speed parameters and transitions the coupling state when speed exceeds a threshold and remains stable for a predetermined time. This parameter-based control resolves the contradiction by adapting the coupling state to actual operating conditions, reducing energy losses during high-speed stable operation while maintaining capability during acceleration phases.
2Loss of energy
If the traction machine is decoupled from the wheel set, then energy losses are minimized, but the vehicle loses traction capability and response time during acceleration phases
Solution Approach 1:
The patent applies preliminary action by anticipating the need for traction before it is required. The system maintains the traction machine in a coupled state during acceleration phases and only decouples when the vehicle reaches a threshold speed and stabilizes for a predetermined duration. This preliminary maintenance of coupling ensures that when acceleration is needed, the traction machine is already positioned to provide immediate response, while still allowing decoupling during stable high-speed operation to minimize energy losses.
Solution Approach 2:
The patent implements feedback by continuously monitoring vehicle speed and using this information to control the coupling state. The control system receives feedback about current speed, compares it against threshold values, and adjusts the coupling state accordingly. This feedback mechanism ensures that the traction machine remains coupled during acceleration phases when traction capability is needed, while decoupling during high-speed stable operation to minimize energy losses, thus resolving the contradiction between energy efficiency and operational capability.
3Loss of time
If coupling/decoupling decisions are made quickly, then the system responds rapidly to changing conditions, but the risk of premature decoupling increases leading to loss of traction capability
Solution Approach 1:
The patent applies preliminary action by requiring that the vehicle speed not only exceed the threshold value but also remain stable for a predetermined duration before triggering decoupling. This preliminary stability check ensures that decoupling decisions are made only when the vehicle is truly in a stable high-speed state, preventing premature decoupling during transient acceleration phases. The predetermined duration acts as a buffer that maintains reliability while still enabling relatively quick response to genuine decoupling conditions.
Solution Approach 2:
The patent implements beforehand cushioning by introducing a time buffer (predetermined duration) between the moment speed exceeds the threshold and the actual decoupling action. This cushioning period allows the system to confirm that the speed increase is sustained and not transient, thereby cushioning against premature decoupling decisions. This approach maintains reliable traction capability while still enabling relatively rapid response to legitimate decoupling conditions, resolving the contradiction between response speed and reliability.
Data Source
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Figure 3A
AI summary
The invention relates to a method for controlling the coupling/uncoupling of a drive machine of a motor vehicle to/from at least one set of wheels of the vehicle, comprising steps that make possible the determination (120) of a time (t_C1) when a torque set point (Croue_cons) to be applied to at least one set of wheels of the vehicle is less (110) than a predetermined coupling threshold (C1) or greater than a predetermined uncoupling threshold, followed by the calculation (140) of a first parameter (PT1) and/or a second parameter (PS2) which depend on said time (t_C1), and finally the authorization (160) of the coupling/uncoupling when said first parameter (PT1) is greater (150) than a first predetermined value (t1) and/or when said second parameter (PS1) is greater (150) than a second predetermined value (S1).