Hybrid Vehicle Deceleration Control via Slope-Aware Speed Profiling
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Solution Overview
Problem
Hybrid vehicles face challenges in maintaining deceleration driving performance and target speed following, often resulting in degraded deceleration feeling and potential traffic flow obstruction due to rapid deceleration, especially when approaching deceleration points like traffic lights.
Innovation Solution
A control method that calculates a deceleration target speed profile based on deceleration event information, including road slope and traffic conditions, allowing the vehicle to adjust its deceleration strategy to maintain performance and charge the battery during deceleration, using a controller to operate the driving motor accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the vehicle performs rapid deceleration to maintain deceleration driving performance, then the deceleration response is improved, but the deceleration feeling is degraded and traffic flow may be obstructed
Solution Approach 1:
The controller determines a target deceleration profile in advance based on deceleration event information (such as traffic light information and road slope) before the vehicle actually decelerates. This preliminary determination allows the vehicle to plan its deceleration trajectory ahead of time, ensuring both responsive deceleration and smooth deceleration feeling by avoiding sudden, unplanned braking actions.
Solution Approach 2:
The controller dynamically adjusts the deceleration control by determining a target deceleration profile that varies based on current vehicle speed, road slope, and deceleration event information. The control strategy transitions from constant deceleration to speed-dependent deceleration, making the deceleration process adaptive and optimized for different driving conditions, thereby improving both response and comfort.
2Measurement precision
If the vehicle follows a predetermined deceleration profile, then the target speed following performance is improved, but the deceleration driving performance is degraded
Solution Approach 1:
The controller changes the deceleration control parameters from fixed predetermined values to dynamic values determined in real-time based on current vehicle speed and road conditions. The target deceleration profile is recalculated considering the slope of the road and actual vehicle state, allowing the system to maintain precise target speed following while adapting deceleration performance to current driving conditions.
3Device complexity
If the vehicle decelerates without considering road slope, then the control simplicity is maintained, but the deceleration performance is degraded
Solution Approach 1:
The controller integrates multiple functions into a unified deceleration control system that simultaneously considers deceleration event information, current vehicle speed, and road slope. This multi-functional approach allows the single controller to handle various deceleration scenarios (flat road, uphill, downhill) without requiring separate control systems, maintaining control simplicity while improving deceleration performance through comprehensive parameter consideration.
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 method enhances deceleration driving performance and target speed following, improving fuel efficiency and battery charging during coasting control, while optimizing deceleration control for autonomous vehicles.
Implementation Method 1
a starter-generator that starts the engine or generates electricity by output of the engine
Data Source
AI summary
A method for controlling deceleration of an environmentally friendly vehicle is provided. The method includes determining a target deceleration profile of the environmentally friendly vehicle based on deceleration event information in ahead of the vehicle and a current speed of the vehicle. A deceleration target speed profile of the vehicle is calculated based on the target deceleration profile. A driving motor of the vehicle is then operated based on the deceleration target speed profile to decelerate the vehicle.