Cruise Control Reference Speed Adjustment for Coasting Optimization
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Solution Overview
Problem
Existing vehicle systems for reducing fuel consumption during coasting are inconsistent and inefficient, often suspending coasting unnecessarily, leading to increased fuel consumption and reduced profitability for haulage companies.
Innovation Solution
A method that adjusts the reference speed in cruise control systems by comparing the requested drive force with a threshold value, allowing coasting to continue when the reference speed is lowered, thereby optimizing fuel savings and consistency in transmission mode selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coasting is suspended when reference speed is temporarily reduced, then vehicle speed control stability is improved, but fuel consumption increases due to unnecessary interruption of fuel-saving coasting mode
Solution Approach 1:
The system performs preliminary evaluation of the reference speed reduction duration and magnitude before suspending coasting. By assessing whether the reduction is temporary or sustained in advance, the system avoids premature interruption of coasting mode, thereby maintaining fuel efficiency while ensuring speed control stability when necessary.
Solution Approach 2:
The coasting suspension decision is made dynamic rather than static. The system continuously monitors reference speed adjustments and adapts the coasting suspension decision based on the actual duration and magnitude of speed reductions, allowing coasting to continue during temporary reductions while suspending it only when sustained reductions indicate a need for active speed control.
2Use of energy by moving object
If coasting is continued during reference speed reduction, then fuel consumption is reduced, but vehicle speed may deviate from desired cruise control target
Solution Approach 1:
The system implements feedback monitoring of actual vehicle speed during coasting operations. When reference speed is reduced, the system continuously compares actual speed against the adjusted reference and determines whether coasting should continue based on whether speed deviations remain within acceptable thresholds, thereby maintaining both fuel efficiency and speed accuracy.
3Speed
If existing cruise control systems suspend coasting on any reference speed reduction, then speed control responsiveness is improved, but fuel savings consistency is reduced due to frequent unnecessary interruptions
Solution Approach 1:
The system performs preliminary assessment of reference speed reductions to distinguish between temporary adjustments and sustained speed changes. By evaluating the duration and magnitude of speed reductions before suspending coasting, the system maintains coasting consistency during normal cruise control operations while remaining responsive to genuine speed control needs.
Data Source
AI summary
A method and a system for controlling a cruise control and a transmission in a vehicle over the course of a road section, wherein prior to the road section, the vehicle has applied coasting and utilizes the cruise control. A reference speed vref utilized in the cruise control during the coasting is lowered to a lowest permitted speed vmin defined for the road section if the lowering is deemed applicable. A comparison of a drive force Fdd requested from an engine system in the vehicle with a threshold value Flim for the drive force is also carried out. The coasting is then suspended if the requested drive force Fdd exceeds the threshold value Flim for the drive force.