Hybrid Vehicle Deceleration Torque Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hybrid vehicles face challenges in controlling deceleration efficiently, as drag torque decreases with vehicle speed, leading to suboptimal energy recovery and fuel conservation during deceleration events.
Innovation Solution
A vehicle control system that generates drag torque based on engine fuel shut-off torque and desired electric power output, limiting it to a threshold to ensure efficient energy recovery and power management, utilizing a controller to balance engine and electric machine contributions during deceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If drag torque is increased to improve energy recovery during deceleration, then energy recovery efficiency is improved, but operator discomfort increases due to excessive deceleration force
Solution Approach 1:
The system dynamically adjusts the drag torque parameter based on vehicle speed and deceleration rate. The controller modulates the magnitude of drag torque applied to the powertrain, ensuring it remains within an optimal range that maximizes energy recovery while preventing excessive deceleration forces that would cause operator discomfort.
Solution Approach 2:
The controller continuously monitors vehicle speed, deceleration rate, and powertrain state, then adjusts drag torque in real-time based on this feedback. This closed-loop control ensures that energy recovery is optimized while maintaining comfortable deceleration characteristics for the operator.
2Use of energy by moving object
If drag torque is limited to threshold values during deceleration, then fuel efficiency is improved through fuel shut-off, but energy recovery is reduced
Solution Approach 1:
The system dynamically determines threshold values for drag torque based on real-time operating conditions including vehicle speed, engine state, and battery charge state. The controller adjusts these thresholds dynamically to maximize both fuel efficiency through shut-off and energy recovery, rather than using fixed conservative limits.
Solution Approach 2:
The system changes the operational parameters of the engine and electric machine based on deceleration conditions. The controller modulates engine torque output and electric machine charging rates to optimize the balance between fuel conservation and energy recovery, adapting parameters such as fuel injection timing and electric machine torque commands.
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 system effectively manages deceleration by optimizing drag torque, ensuring efficient energy recovery and power distribution, enhancing fuel efficiency and reducing operator discomfort by maintaining a consistent deceleration rate.
Implementation Method 1
a generator and a controller. The engine and the generator are respectively configured to, in response to an accelerator pedal lift-off event, produce a fuel shut-off torque and produce a drag torque
Implementation Method 2
produce a fuel shut-off torque
Data Source
AI summary
A vehicle control system includes a controller that is programmed to, in response to an accelerator lift-pedal event, generate a drag torque, with at least one of an engine and electric machine, having a magnitude that is based on a deceleration fuel shut-off torque of the engine and a desired power output of the electric machine, and limit the drag torque to a threshold value that is based on the deceleration fuel shut-off torque.