Hybrid Powertrain Torque Control Using Battery SOH Feedback

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Solution Overview

Problem

Existing hybrid powertrain systems face challenges in efficiently managing energy generation and maintaining the state of health of energy storage devices, particularly in balancing torque demands and preserving battery health while optimizing fuel efficiency.

Innovation Solution

The system includes a controller that determines a first torque output for a genset based on torque demand and state of charge, adjusts this output based on state of health, and operates both the genset and a second motor-generator to meet torque demands while maintaining or exceeding a predefined state of health trajectory for the energy storage device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the genset operates at high torque output to meet vehicle demand, then vehicle performance is maintained, but fuel efficiency deteriorates

Engineering Contradiction:
Improvetorque outputVSAvoidfuel efficiency
Core Design Contradiction:
PowerVSUse of energy by moving object

Solution Approach 1:

The control system dynamically adjusts the genset torque output based on real-time SOH measurements and vehicle conditions. When SOH is high, the system allows higher torque output from the genset; when SOH is low, it reduces genset torque and relies more on the battery, optimizing the balance between vehicle performance and fuel efficiency throughout the battery lifecycle.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters of the genset based on battery SOH. By monitoring SOH and adjusting the torque allocation between genset and battery accordingly, the system adapts its energy management strategy to maintain fuel efficiency while ensuring vehicle performance requirements are met at different stages of battery life.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If the genset generates more energy to maintain fuel efficiency, then fuel consumption is reduced, but battery degradation accelerates

Engineering Contradiction:
Improvefuel efficiencyVSAvoidbattery health
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The control system continuously monitors battery SOH and uses this feedback to adjust genset energy generation. When SOH drops below certain thresholds, the system reduces genset torque output and increases battery usage, preventing excessive degradation. This closed-loop feedback mechanism ensures fuel efficiency is optimized without compromising long-term battery reliability.

Inventive Principle:
Principle #23Feedback

3Duration of action of stationary object

If the system prioritizes battery health by reducing genset operation, then battery life is extended, but fuel efficiency deteriorates

Engineering Contradiction:
Improvebattery lifeVSAvoidfuel efficiency
Core Design Contradiction:
Duration of action of stationary objectVSUse of energy by moving object

Solution Approach 1:

The system dynamically balances battery protection and fuel efficiency based on real-time SOH conditions. Rather than statically limiting genset operation, the control algorithm continuously optimizes the split between battery and genset contribution, ensuring battery life is extended through appropriate protection while minimizing fuel efficiency penalties by utilizing the genset when beneficial.

Inventive Principle:
Principle #15Dynamics

4Reliability

If the control system frequently adjusts torque allocation based on SOH, then battery health is optimized, but system complexity increases

Engineering Contradiction:
Improvebattery healthVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control system autonomously manages torque allocation based on SOH measurements without requiring complex external intervention. By implementing self-service logic that automatically adjusts genset-battery torque splitting based on monitored SOH conditions, the system optimizes battery health through straightforward rule-based control rather than complex algorithms, minimizing system complexity while achieving reliability goals.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3619084B1Systems and methods for controlling energy generation in a hybrid powertrain
Publication Date: 2023.09.06 CUMMINS INC
  • EP3619084B1 patent drawingFigure 1
  • EP3619084B1 patent drawingFigure 2
  • EP3619084B1 patent drawingFigure 3

AI summary

An apparatus includes an energy storage circuit, an input circuit, and a hybrid management circuit. The energy storage circuit is structured to receive a state of charge (SOC) and a state of health (SOH) of an energy storage device. The input circuit is structured to receive an indication of a torque demand. The hybrid management circuit is structured to determine a first torque output for a genset including an engine and a first motor-generator based on the torque demand and the SOC of the energy storage device; determine an adjustment factor based on the SOH of the energy storage device; determine an adjusted torque output for the genset based on the adjustment factor and the first torque output; operate the genset to provide the adjusted torque output and to generate an amount of energy; and operate a second motor-generator at a second torque output to meet the torque demand.