Vehicle Control Device Upshift Logic for Slope-Related Fuel Efficiency
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Solution Overview
Problem
Fuel consumption in vehicles increases when slope changes on the road due to inappropriate gear stage selection, as existing automatic transmissions prioritize drive force over travel resistance.
Innovation Solution
A vehicle control device and method that determines upcoming road segments with different slopes, selecting a gear stage based on travel resistance and drive force, and controls upshifting to optimize gear changes, ensuring the drive force exceeds travel resistance by a predetermined value, thereby reducing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a high gear stage is selected to reduce fuel consumption, then fuel efficiency improves, but acceleration capability deteriorates when traveling on upslopes
Solution Approach 1:
The control device performs preliminary determination of the next travel segment and its road slope before the vehicle actually enters it. Based on this advance information, the system pre-calculates the appropriate gear stage to be selected when the slope changes, allowing the vehicle to maintain optimal fuel efficiency while ensuring adequate acceleration capability is available when needed.
Solution Approach 2:
The gear stage selection is made dynamic by continuously monitoring travel segment information and road slope changes. The system adjusts the gear stage based on real-time conditions rather than using a fixed selection criterion, enabling the vehicle to adapt between fuel-efficient high gear selection on flat terrain and acceleration-capable low gear selection on upslopes.
2Force
If gear stage selection is based on allowance drive force (maximum drive force minus travel resistance), then acceleration capability is maintained, but fuel consumption increases due to conservative gear selection
Solution Approach 1:
The system determines the next travel segment and its characteristics in advance, allowing it to pre-calculate the optimal gear stage before the vehicle actually encounters the slope change. This preliminary action enables more aggressive (higher) gear selection that would be too risky if made reactively, thereby reducing fuel consumption while maintaining safety.
Solution Approach 2:
The invention changes the parameter used for gear stage selection from conservative allowance drive force calculation to a more optimized approach that considers the specific road slope of the next travel segment. By changing this selection parameter based on actual road conditions rather than worst-case assumptions, the system achieves better fuel efficiency without sacrificing necessary acceleration capability.
3Use of energy by moving object
If upshifting is performed in the current travel segment based on next segment conditions, then fuel consumption is reduced, but drive force may become insufficient in the current segment
Solution Approach 1:
The control device performs the upshifting operation in advance within the current travel segment, before the vehicle actually enters the next travel segment with different road slope. This preliminary upshifting allows the engine to operate at lower RPM in the upcoming segment, reducing fuel consumption, while ensuring that sufficient drive force is still available during the transition period in the current segment.
Data Source
AI summary
This vehicle control devices provided with: a travel segment determination unit 15 which determines a next travel segment, forwards in the travel direction of the vehicle, which has a different road slope from the current travel segment where the vehicle is currently traveling; a next gear stage selection unit 16 which, on the basis of the road slope of the next travel segment, selects a next gear stage, which will be the gear stage of the vehicle in the next travel segment; and a shift control unit 17 which upshifts to the next gear stage in the current travel segment in the case that the travel resistance in the next travel segment is less than the travel resistance of the current travel segment, the value obtained by subtracting the travel resistance of the vehicle in the current travel segment from the drive force at the current speed of the vehicle in the next gear stage is less than a first prescribed value, and the value obtained by subtracting the travel resistance of the vehicle in the next travel segment from the drive force at the current vehicle speed in the next gear stage is less than a second prescribed value.