Hybrid Powertrain Braking Torque Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hybrid powertrain systems face challenges in efficiently managing torque and energy transfer during braking events, particularly in optimizing engine states and torque distributions to minimize power costs and maximize energy recovery.
Innovation Solution
A control method for a hybrid powertrain system that monitors operator torque requests, detects braking events, evaluates candidate input torques from the engine, and determines preferred engine states and input torques to minimize power costs by selectively operating the engine in all-cylinder, cylinder deactivation, fueled, and fuel cutoff states, while utilizing electric machines for regenerative braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the engine operates in all-cylinder fueled state during braking, then torque availability is maximized, but fuel consumption increases
Solution Approach 1:
The engine dynamically transitions between multiple operational states (all-cylinder fueled, all-cylinder fuel cutoff, cylinder deactivation fueled, cylinder deactivation fuel cutoff) based on real-time braking conditions and torque requirements, optimizing the balance between torque availability and fuel consumption
Solution Approach 2:
The system changes engine operating parameters including cylinder activation state and fuel injection status to select the most efficient engine mode for current braking conditions, thereby reducing fuel consumption while maintaining adequate torque
2Loss of energy
If regenerative braking is maximized, then energy recovery is improved, but torque distribution complexity increases
Solution Approach 1:
The control system continuously monitors braking torque requirements, engine state, and transmission conditions, using feedback to dynamically adjust torque distribution between regenerative and friction braking to maximize energy recovery while managing system complexity
Solution Approach 2:
The torque machine serves multiple functions: it acts as a motor during acceleration, a generator during regenerative braking, and provides torque fill-in during blending, thereby simplifying control architecture through multi-functionality
3Ease of operation
If friction braking is used exclusively, then control simplicity is maintained, but energy recovery is minimized
Solution Approach 1:
The system converts the traditionally wasted kinetic energy during braking into usable electrical energy through regenerative braking, transforming energy loss into energy recovery while maintaining blended control strategy
4Use of energy by moving object
If engine torque is reduced during braking, then fuel efficiency improves, but torque fill-in requirements increase
Solution Approach 1:
The torque machine acts as an intermediary, providing torque fill-in to compensate for reduced engine torque during braking, thereby maintaining fuel efficiency while meeting vehicle torque requirements
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 effectively manages torque and energy transfer during braking, optimizing engine operation to reduce power costs and enhance energy recovery by identifying the most efficient engine states and torque distributions, thereby improving fuel efficiency and reducing emissions.
Implementation Method 1
Machines, operative as motors or generators, can generate torque inputs to the transmission independently of a torque input from the internal combustion engine. The machines may transform vehicle kinetic energy transmitted through the vehicle driveline to energy that is storable in an energy storage device.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A hybrid transmission is operative to transfer power between an input member (12) and a torque machine (56,72) and an output member (64). A method for controlling the powertrain system during a braking event includes evaluating candidate input torques. An output torque reactable through the transmission (10) to the driveline (90) and limited within the range of permissible output torques is determined for the candidate engine input torque. A preferred input torque is determined.