Torque Distribution Device for Four-Wheel Drive Vehicles
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Solution Overview
Problem
Current methods for distributing engine torque between the front and rear axles of four-wheel drive vehicles do not effectively account for off-road conditions, leading to suboptimal traction and fuel efficiency, especially when vehicle speed is low or medium.
Innovation Solution
A device and method that calculate a torque distribution setpoint based on vehicle speed and speed difference between axles, adjusting the torque distribution strategy according to specific thresholds to optimize traction and reduce fuel consumption in off-road modes, including the use of actuator-controlled torque distribution and calculation means to determine torque setpoints as a function of vehicle conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a cubic function of vehicle speed is used to calculate speed offset for torque distribution, then torque distribution can be optimized for road conditions, but the method does not account for off-road conditions especially at low or medium speeds
Solution Approach 1:
The patent implements dynamic torque distribution strategies that adapt to different vehicle operating conditions. The control system dynamically switches between a first torque distribution strategy (for low speeds with obstacle crossing priority) and a second torque distribution strategy (for higher speeds with fuel efficiency priority), ensuring reliable performance across both off-road and road conditions
Solution Approach 2:
The patent changes the parameters of torque distribution based on vehicle speed and operating conditions. By monitoring vehicle speed and comparing it against threshold values, the system adjusts torque distribution parameters to optimize performance for off-road obstacle crossing at low speeds while improving fuel efficiency at higher speeds
2Reliability
If torque distribution favors obstacle clearance capability, then crossing capacity is improved, but fuel consumption increases
Solution Approach 1:
The system dynamically adjusts torque distribution based on real-time vehicle speed measurements. At low speeds, the first strategy prioritizes obstacle clearance by distributing torque to maximize traction. At higher speeds, the second strategy prioritizes fuel efficiency by optimizing torque distribution for economical operation, thus resolving the energy-capability trade-off dynamically
Solution Approach 2:
The patent applies partial torque distribution strategies tailored to specific operating conditions. Instead of continuously maximizing torque for obstacle clearance, the system applies the aggressive torque distribution strategy (first strategy) only when necessary at low speeds, and switches to a more moderate, fuel-efficient strategy (second strategy) at higher speeds, avoiding excessive energy consumption
3Use of energy by moving object
If torque distribution is optimized for fuel consumption, then fuel efficiency improves, but traction and crossing capacity are reduced
Solution Approach 1:
The control system dynamically switches between two torque distribution strategies based on vehicle speed. The first strategy (for low speeds) prioritizes traction and obstacle clearance capability. The second strategy (for higher speeds) prioritizes fuel efficiency. This dynamic switching ensures that traction is maximized when needed while fuel efficiency is optimized during normal driving
Solution Approach 2:
The system changes torque distribution parameters based on vehicle operating conditions. By monitoring vehicle speed and comparing it against predefined thresholds, the system adjusts the torque distribution strategy to maintain adequate traction during off-road operations while improving fuel efficiency during higher-speed road driving conditions
Data Source
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AI summary
The invention relates to a device (1) for distributing engine torque between the front end (2) and the rear end (3) of a motor vehicle having at least four drive wheels (3, 4, 6, 7), including: a controlled actuator (13) configured to distribute the engine torque; a calculating means (30) for calculating the speed of the vehicle and the speed loss between a front end (2) and the rear end (5); and a generating means (31) for generating a torque distribution set value for the actuator (13), said generating means (31) comprising an initial determination means (40) for determining a first value of the torque distribution set value, said first value being equal to: a maximum constant if the speed of the vehicle is below a lower threshold; a function of the speed of the vehicle and of the speed loss if the speed of the vehicle is between the lower and upper thresholds; or zero if the speed of the vehicle is above the upper threshold.