Following Travel Coasting Control for Large-Vehicle Slipstream
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Solution Overview
Problem
Conventional vehicle driving support systems fail to prevent an own vehicle from approaching too closely to a preceding vehicle during following travel control, especially when the preceding vehicle is large, leading to decreased energy efficiency due to increased air resistance.
Innovation Solution
A vehicle driving support device that predicts a minimum inter-vehicle distance based on the size of the preceding vehicle and adjusts the timing of coasting to maintain an appropriate distance, taking into account air resistance, thereby preventing the own vehicle from getting too close.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the own vehicle starts coasting immediately after switching from powering state to maintain energy efficiency, then energy consumption is reduced, but the own vehicle approaches too close to the preceding vehicle due to reduced air resistance force
Solution Approach 1:
The control device predicts the minimum inter-vehicle distance before actually starting coasting. By performing this prediction calculation in advance while the vehicle is still in powering state, the system can determine whether coasting should be initiated, preventing the harmful effect of getting too close while still enabling energy-efficient coasting when safe
Solution Approach 2:
The system uses feedback from the predicted minimum inter-vehicle distance to control the timing of coasting initiation. The prediction result feeds back to the control decision, allowing the system to adjust coasting timing based on the calculated safety margin, thus resolving the contradiction between energy efficiency and safety distance
2Object-affected harmful factors
If the own vehicle maintains a larger inter-vehicle distance to prevent getting too close, then safety is improved, but energy efficiency decreases due to increased air resistance force
Solution Approach 1:
The system dynamically changes the effective safety distance parameter by predicting the minimum inter-vehicle distance and comparing it with a predetermined safe distance. This parameter adjustment allows the vehicle to optimize the balance between maintaining safety margin and reducing air resistance for energy efficiency
Solution Approach 2:
By predicting the minimum inter-vehicle distance in advance before coasting begins, the system can determine the optimal timing to start coasting. This preliminary prediction allows the vehicle to maintain larger distance when necessary while still capturing energy-saving opportunities when safe
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device effectively maintains a safe inter-vehicle distance by optimizing the timing of coasting, reducing air resistance, and enhancing energy efficiency during following travel control.
Implementation Method 1
the air resistance force to the own vehicle is smaller as the size of the preceding vehicle is larger
Data Source
AI summary
A vehicle driving support device allows a vehicle to travel such that an inter-vehicle distance between the vehicle and a preceding vehicle falls within a predetermined range by repeatedly powering and coasting the vehicle while following travel control is executed. The vehicle driving support device sets a lower limit value of the predetermined range as a target inter-vehicle distance while the following travel control is executed, predicts as a minimum inter-vehicle distance a minimum value of the inter-vehicle distance after the vehicle starts coasting at a current point in time when the vehicle is powered due to the following travel control, and starts coasting the vehicle when the minimum inter-vehicle distance is equal to or shorter than the target inter-vehicle distance. The minimum inter-vehicle distance is predicted to be a shorter distance when a size of the preceding vehicle is large than when that of the preceding vehicle is small.