Vehicle Coasting Control via Speed Difference Threshold
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Solution Overview
Problem
Current methods for controlling rolling or coasting functions in vehicles fail to accurately recognize suitable driving situations, leading to inefficient energy savings and potential tractive power deficits, particularly in heavy commercial vehicles, due to insufficient consideration of topographical conditions and vehicle status.
Innovation Solution
A method for controlling rolling or coasting functions in vehicles with automatic or automated transmissions, using a vehicle speed control device to selectively restore traction based on a speed difference between the current vehicle speed and a lower limit speed, allowing flexible adhesion restoration in response to changing topography and vehicle parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the drive train is interrupted early to activate coasting mode, then fuel savings are improved, but tractive power availability deteriorates
Solution Approach 1:
The patent implements dynamic control of the drive train interruption by continuously monitoring vehicle acceleration, speed, and route topography. The coasting mode is activated and deactivated based on real-time conditions rather than fixed rules, allowing the system to adapt to changing driving situations and optimize the balance between fuel savings and power availability.
Solution Approach 2:
The system uses feedback from vehicle sensors (acceleration, speed, torque requests) and route information (gradient, curvature) to continuously evaluate whether coasting mode should be maintained or terminated. This feedback mechanism ensures that the drive train is re-engaged promptly when power is needed while maximizing coasting duration for fuel efficiency.
2Power
If the drive train is interrupted late to activate coasting mode, then tractive power availability is improved, but fuel savings deteriorate
Solution Approach 1:
The system performs preliminary evaluation of route topography and current vehicle state before activating coasting mode. By predicting future power needs based on upcoming gradients and curvature, the system can safely extend coasting duration to maximize fuel savings while ensuring power is available when required.
3Loss of energy
If coasting mode is extended on downhill sections, then fuel savings are improved, but vehicle control and safety deteriorate
Solution Approach 1:
The system continuously monitors vehicle acceleration, speed, and torque requests during coasting mode on downhill sections. When feedback indicates that power assistance is needed for safety or control reasons, the system promptly terminates coasting mode and re-engages the drive train, ensuring vehicle control is maintained while maximizing fuel savings when safe.
4Device complexity
If simple control rules are used for coasting activation, then device complexity is reduced, but recognition accuracy of suitable driving situations deteriorates
Solution Approach 1:
The patent leverages existing multi-functional vehicle systems (cruise control, brake control, route navigation) to perform coasting control. By reusing existing sensors, processors, and data structures across multiple vehicle functions, the system achieves accurate situation recognition without proportionally increasing hardware complexity.
Data Source
Figure 1
AI summary
The invention relates to a method for controlling a rolling or coasting function of a vehicle, such as a commercial vehicle (1), comprising a drive train having a drive motor, an automatic or automated gearbox, which can be actuated via a gear control, the gearbox having actuatable shifting means for interrupting the frictional connection in the drive train, and a travel speed control unit, wherein the frictional connection in the drive train is interrupted in a suitable travel situation. In order to allow for the rolling or coasting function to be utilized as efficiently as possible, while maintaining the possibility to terminate it safely and conveniently, the frictional connection in the drive train is reestablished depending on a selectable speed difference (?v_F_T) between the current vehicle speed (v_F) and a lower limit speed (v_T) determined by means of the travel speed control unit.