Vehicle Running Control Device for Fuel Efficiency Optimization
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Solution Overview
Problem
Conventional running control devices for vehicles fail to improve fuel efficiency by restricting engine rotations, especially when running resistance increases, as the restriction is only applied during changes in vehicle speed or gear ratios, leading to suboptimal fuel efficiency in areas with unchanged driving force transmission states.
Innovation Solution
A running control device that includes a vehicle speed sensor, target vehicle speed setting, target driving force calculation, driving force control, allowed lowering value setting, and target driving force upper limit calculation, which dynamically adjusts the target driving force based on actual vehicle speed deviations and road gradients to optimize fuel efficiency without discomfort to the driver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If restriction of the number of engine rotations is applied only when vehicle speed changes or transmission state changes, then the control system remains simple and responsive, but fuel efficiency cannot be improved in areas where the driving force transmission state does not change
Solution Approach 1:
The patent applies dynamics by continuously adjusting the target driving force based on real-time vehicle speed deviations from the target speed. Instead of using fixed restriction thresholds, the system dynamically calculates the upper limit of target driving force according to the magnitude of speed deviation, allowing flexible adaptation to varying road conditions and vehicle states without requiring complex discrete control logic
Solution Approach 2:
The patent changes the parameter of target driving force upper limit based on vehicle speed deviation. By establishing a relationship where the maximum allowable target driving force varies with the degree of speed deviation, the system achieves continuous optimization of fuel efficiency while maintaining simple control structure through parameter interdependence rather than complex control rules
2Use of energy by moving object
If the target driving force is restricted to improve fuel efficiency, then fuel consumption decreases, but the vehicle's ability to respond to increased running resistance deteriorates
Solution Approach 1:
The patent implements feedback control by continuously monitoring actual vehicle speed and comparing it with target vehicle speed. The target driving force upper limit is adjusted based on the feedback from speed deviation, ensuring that when vehicle speed drops below target (indicating increased running resistance), the restriction is relaxed to allow sufficient driving force for recovery, thus maintaining reliability while optimizing fuel efficiency during normal operation
Solution Approach 2:
The patent applies partial restriction of target driving force by establishing an upper limit rather than complete restriction. The system allows the target driving force to reach the calculated upper limit when needed (such as when speed deviation exceeds thresholds), providing excessive action capability to overcome running resistance, while maintaining fuel efficiency through restriction during normal operating conditions
Data Source
AI summary
A vehicle running control device including: a vehicle speed sensor which detects an actual vehicle speed; a target vehicle speed setting unit; a target drive force calculation unit; a drive force control unit; a vehicle speed lowering allowance value setting unit; and a target drive force upper limit calculation unit. If the actual vehicle speed lowering amount with respect to the target vehicle speed is within the lowering allowance value, the target drive force calculation unit limits the target drive force to be not greater than the target drive force upper limit and the drive force control unit executes drive force control in accordance with the limited target drive force.