Vehicle Slope Control Engine Speed Adaptation
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Solution Overview
Problem
Existing vehicle control systems face challenges in balancing drivability and fuel consumption efficiency on slope roads, particularly when a driver's acceleration/deceleration operation is not performed, as the engine rotation speed is kept high to ensure drivability but may lead to increased fuel consumption and poor driver feedback.
Innovation Solution
A vehicle control device that includes a slope-road running control portion to manage engine rotation speed, allowing it to be higher on slope roads compared to flat roads, with a second running mode that limits the increase in engine rotation speed without driver input, optimizing fuel efficiency and drivability based on driver demand and running mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine rotation speed is kept high during slope-road running to ensure drivability, then the drivability is improved, but the fuel consumption increases
Solution Approach 1:
The patent applies dynamics by making the engine rotation speed control adaptive to different running modes. The control device dynamically adjusts the engine rotation speed based on whether the vehicle is in a first running mode (with driver acceleration/deceleration operation) or a second running mode (without driver acceleration/deceleration operation). This dynamic adjustment allows the system to optimize drivability when needed while reducing fuel consumption when driver demand is low.
Solution Approach 2:
The patent changes the parameter of engine rotation speed based on running mode. In the first running mode, the engine rotation speed is maintained at a higher level to ensure drivability on slope roads. In the second running mode, the engine rotation speed is limited to a lower increase amount, thereby reducing fuel consumption. This parameter change strategy directly addresses the contradiction between drivability and fuel consumption.
2Speed
If the engine rotation speed is kept high on uphill roads to improve reacceleration performance, then the reacceleration performance is improved, but the fuel consumption deteriorates
Solution Approach 1:
The control device dynamically adjusts engine rotation speed control based on the detected running mode. When in the first running mode, the system allows higher engine rotation speed to improve reacceleration performance on uphill roads. When in the second running mode, the system limits the engine rotation speed increase, accepting reduced reacceleration performance in exchange for lower fuel consumption, since driver acceleration demand is already low.
Solution Approach 2:
The patent changes the engine rotation speed parameter according to the running mode. In the first running mode, the engine rotation speed is maintained high to ensure reacceleration performance. In the second running mode, the increase amount of engine rotation speed is limited, thereby reducing fuel consumption while the driver is less likely to feel strange about the reduced performance.
3Force
If the engine rotation speed is increased by downshift to acquire engine braking force on downhill road, then the engine braking force is improved, but the fuel consumption increases
Solution Approach 1:
The control device dynamically adjusts the engine rotation speed control based on the running mode. In the first running mode, the system allows engine rotation speed to be maintained high through downshift control to provide sufficient engine braking force on downhill roads. In the second running mode, the system limits the engine rotation speed increase amount, reducing fuel consumption while providing adequate engine braking force for the reduced driver demand scenario.
Data Source
AI summary
A vehicle control device for a vehicle including an engine used as a power source and an automatic transmission, the vehicle control device performing a first running mode in which a shift control of the automatic transmission and a drive force control are provided according to a driver's acceleration/deceleration operation and a second running mode in which the shift control and the drive force control are provided without the acceleration/deceleration operation while a target running state is set, comprising: a slope-road running control portion configured to control the automatic transmission such that an engine rotation speed is kept high during slope-road running on at least one of an uphill road and a downhill road as compared to flat-road running, the slope-road running control portion limiting an increase amount of the engine rotation speed in the second running mode as compared to the first running mode.