Torque Distribution Control for Hybrid Vehicle Stability and Efficiency
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Solution Overview
Problem
Existing vehicle driving force control systems for electric or hybrid vehicles fail to simultaneously optimize energy efficiency and driving stability, often resulting in hunting issues and non-monotonic energy efficiency changes when distributing torque across multiple drive sources and wheels.
Innovation Solution
A vehicle driving force control apparatus that includes a ratio determination unit to select a target distribution ratio based on candidate ratios with low energy loss and high driving stability, adjusting the ratio range and priority according to vehicle state parameters such as speed, steering angle, and battery charging rate, and incorporating sensors for real-time feedback to optimize torque distribution between front and rear wheels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the required torque is distributed at a first distribution ratio that improves energy efficiency, then energy efficiency increases, but driving stability deteriorates
Solution Approach 1:
The patent applies dynamics by making the torque distribution ratio adjustable and switchable between multiple predetermined ratios (first ratio for energy efficiency, second ratio for driving stability) based on real-time vehicle conditions. The control unit dynamically selects the appropriate distribution ratio according to parameters such as vehicle speed, acceleration, and steering angle, allowing the system to transition from a static to a dynamic control strategy that optimizes both energy efficiency and driving stability under different operating conditions.
2Reliability
If the distribution ratio switches between first and second ratios to handle stability and efficiency, then both aspects are addressed, but hunting occurs increasing transition time
Solution Approach 1:
The patent implements feedback control by continuously monitoring vehicle state parameters (speed, acceleration, steering angle) and using this information to determine when to switch between distribution ratios. The control unit compares current vehicle conditions with predefined thresholds and switching conditions, enabling intelligent, context-aware transitions that prevent hunting by only switching when actual vehicle state changes warrant a ratio change, thereby reducing unnecessary transitions and associated time losses.
3Reliability
If balance distribution control is used with intermediate values, then both energy efficiency and driving stability are considered, but ideal balance is not achieved due to non-monotonic energy efficiency changes
Solution Approach 1:
The patent applies segmentation by dividing the continuous range of possible distribution ratios into discrete predetermined ratios (first ratio, second ratio, and intermediate ratios). Instead of using balance distribution control with intermediate values that fail to achieve ideal balance due to non-monotonic energy efficiency characteristics, the system segments the solution space into specific, pre-optimized ratio options. The control unit selects from these segmented options based on vehicle conditions, ensuring that each selected ratio represents a proven optimal or near-optimal balance point rather than an arbitrary intermediate value.
4Device complexity
If priority is simply switched between energy efficiency and driving stability based on time, then control is simple, but the degree of priority is not adjusted according to various running state parameters
Solution Approach 1:
The patent implements parameter changes by making the torque distribution ratio dependent on multiple vehicle operating parameters including vehicle speed, acceleration, and steering angle. Rather than simply switching priority between energy efficiency and driving stability based on time alone, the control unit evaluates current parameter values against predefined thresholds and switching conditions to determine the appropriate distribution ratio. This parameter-based approach enables the system to adapt to various running states dynamically while maintaining relatively simple control logic through predetermined switching rules.
Data Source
AI summary
A vehicle driving force control apparatus is mounted in a vehicle that runs by transmitting power from a plurality of drive sources to a plurality of wheels or a plurality of sets of wheels. The vehicle driving force control apparatus includes: a ratio determination unit; and a command unit. The ratio determination unit determines a target ratio at which a required driving force applied to the vehicle is to be distributed to the plurality of wheels or the plurality of sets of wheels. The command unit commands the plurality of drive sources to output power such that driving force distributed in accordance with the target ratio is generated in the plurality of wheels or the plurality of sets of wheels.