Vehicle Control Device for Uphill Reacceleration
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Solution Overview
Problem
During sailing stop control, vehicles on uphill roads face insufficient hydraulic pressure for reacceleration due to the automatic transmission's high speed ratio and stopped driving source, leading to inadequate propulsion and delayed acceleration.
Innovation Solution
A control device and method that includes a first control unit for executing driving-source-stop-while-traveling control and a second control unit to cancel this control when the road inclination exceeds a predetermined value, starting the driving source to ensure sufficient hydraulic pressure for the automatic transmission's reacceleration by adjusting the speed ratio and engaging the clutch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If sailing stop control is executed with high speed ratio for fuel efficiency, then fuel consumption is reduced, but hydraulic pressure becomes insufficient for reacceleration on uphill roads
Solution Approach 1:
The control device predicts future road inclination ahead of the vehicle's current position and proactively adjusts the speed ratio before the vehicle actually encounters the uphill section. This preliminary action ensures hydraulic pressure is built up in advance, preventing the contradiction between fuel efficiency and hydraulic pressure availability when reacceleration is needed.
Solution Approach 2:
The system dynamically adjusts the speed ratio based on predicted road conditions rather than maintaining a fixed high ratio during sailing stop control. When uphill roads are predicted, the control device transitions to a lower speed ratio to generate adequate hydraulic pressure, then returns to high ratio mode after passing the uphill section, optimizing both fuel efficiency and hydraulic pressure availability.
2Use of energy by moving object
If driving source is stopped during sailing stop control, then fuel efficiency is improved, but vehicle propulsion becomes insufficient when reacceleration is needed on steep roads
Solution Approach 1:
The control device predicts upcoming uphill sections and proactively reduces the speed ratio before the vehicle reaches them, ensuring hydraulic pressure is sufficient for immediate propulsion when the driving source restarts, thus maintaining both fuel efficiency and adequate vehicle propulsion.
Solution Approach 2:
The system uses feedback from road inclination sensors and predicted road data to continuously adjust the speed ratio. When uphill roads are detected or predicted, the control device modifies the speed ratio to ensure adequate hydraulic pressure and propulsion capability, then returns to fuel-efficient mode when conditions allow.
Data Source
AI summary
A controller is a control device for a vehicle including an engine, an automatic transmission, and an oil pump and executes a sailing stop control that stops the engine and brings the automatic transmission into a neutral state when a sailing stop condition is satisfied. The controller cancels the sailing stop control to start the engine when a road inclination becomes larger than a predetermined value during the sailing stop control.