Torque Distribution Control for Four-Wheel-Drive Sudden Starts
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Solution Overview
Problem
Current driving force distribution control systems in four-wheel-drive vehicles fail to accurately detect sudden starts, especially on low friction road surfaces, leading to wheel slip due to excessive engine torque transmission to auxiliary drive wheels.
Innovation Solution
A driving force distribution control device that reduces torque transmission to auxiliary drive wheels based on vehicle speed, engine rotational speed, and clutch engagement speed, with adjustments for outside temperature and gradient, using a control device and driving force transmitting device to manage torque distribution effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If torque capacity of driving force transmitting members is reduced to achieve lightweight, then weight is reduced, but reliability deteriorates due to inability to handle high torque
Solution Approach 1:
The control device detects sudden start conditions in advance and preemptively reduces torque transmission to auxiliary drive wheels before excessive torque can damage the lightweight transmitting members. This preliminary action prevents reliability failures while maintaining the lightweight design.
Solution Approach 2:
The control device acts as an intermediary between the engine and the driving force transmitting members, regulating torque transmission to protect the lightweight components from excessive torque while allowing full torque transmission under normal conditions.
2Object-affected harmful factors
If torque transmitted to auxiliary drive wheels is reduced during sudden start, then wheel slip is suppressed, but detection precision deteriorates when engine torque is excessive on low friction roads
Solution Approach 1:
The control system dynamically adjusts torque transmission based on real-time detection of clutch engagement speed and engine rotational speed. This dynamic response allows the system to suppress wheel slip during detected sudden starts while adapting to varying road conditions and engine states.
Solution Approach 2:
The control device continuously monitors clutch engagement speed and engine rotational speed, using this feedback to determine sudden start conditions and adjust torque transmission accordingly. This feedback mechanism improves detection accuracy by considering multiple parameters simultaneously.
Data Source
AI summary
A driving force distribution control device mounted on a vehicle including an engine, a transmission device, a clutch engaging an output shaft of the engine with an input shaft of the transmission device, and a driving force transmission system capable of transmitting output of the transmission device to main and auxiliary drive wheels, includes: a control device obtaining a torque value to be transmitted to the auxiliary drive wheels, the control device reducing the torque value for a predetermined time when the vehicle is in a stopped state or in a state where a vehicle speed of the vehicle is lower than a predetermined value, and an increasing speed of engaging force of the clutch is equal to or greater than a predetermined value; and a driving force transmitting device transmitting torque depending on the obtained torque value to the auxiliary drive wheels.