EV Powertrain Coolant Loop Control Using Waste Heat Recovery

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Solution Overview

Problem

Electric vehicles generate substantial waste heat, which can reduce the lifespan and performance of powertrain components, and existing thermal management systems are not efficient in maximizing system performance and preserving battery capacity.

Innovation Solution

A method and system for managing powertrain thermal loads in electric vehicles by utilizing waste heat from electric motors and DC-DC converters, involving a combination of feedback and feedforward control to regulate coolant flow and fan speed, and incorporating a proportional-integral-derivative (PID) control to optimize coolant flow and temperature management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If waste heat from electric motors is used to heat coolant, then energy efficiency is improved, but thermal management system complexity increases

Engineering Contradiction:

Improvewaste heat recoveryVSAvoidthermal management system

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The coolant loop is designed to serve multiple functions: cooling powertrain components during high-temperature operation and providing heated coolant for cabin heating during low-temperature operation. The same coolant circulates through both the powertrain components and the cabin heater, eliminating the need for separate heating and cooling systems.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system captures waste heat generated by electric motors and DC-DC converters, which would otherwise be discarded, and redirects it to heat the coolant. This heated coolant then serves dual purposes: maintaining powertrain component temperatures and providing cabin heating, thereby converting harmful waste heat into a useful resource.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Measurement precision

If feedback and feedforward control are used to regulate fan speed, then thermal management precision is improved, but control system complexity increases

Engineering Contradiction:

Improvetemperature control precisionVSAvoidcontrol system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Temperature sensors continuously monitor coolant temperatures at multiple locations in the loop. The controller receives this feedback information and adjusts the coolant pump speed and radiator fan speed accordingly to maintain optimal temperatures. The feedback loop ensures that temperature deviations are detected and corrected in real-time.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The feedforward control uses a thermal model to predict future temperature conditions based on current operating parameters such as motor power, ambient temperature, and coolant flow rate. The controller proactively adjusts fan and pump speeds before temperature deviations occur, preventing thermal issues rather than merely reacting to them.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If PID control is applied to optimize coolant flow, then thermal management effectiveness is improved, but computational requirements increase

Engineering Contradiction:

Improvethermal management effectivenessVSAvoidcomputational energy

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The PID controller continuously receives feedback from temperature sensors monitoring coolant temperatures at various points in the loop. Based on the temperature errors detected, the controller dynamically adjusts the coolant pump speed to maintain optimal flow rates, ensuring reliable thermal management while using computationally efficient algorithms suitable for embedded controllers.

Inventive Principle:

Principle #23Feedback

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

This approach effectively manages thermal loads, enhancing the lifespan and performance of powertrain components, reduces power consumption from batteries, and preserves battery capacity for increased vehicle range.

Implementation Method 1

controlling a fan speed of a radiator fan for the powertrain coolant loop

Methodology Applied

Scientific EffectForced Convection: Forced Convection

Implementation Method 2

heating a coolant of a powertrain coolant loop utilizing waste heat from an electric motor and/or a DC-DC converter

Methodology Applied

Scientific EffectThermal Conduction: Conduction (thermal)

Data Source

PatentUS12095061B2Systems and methods for electric vehicle powertrain thermal management and control

Publication Date: 2024.09.17 HYROAD NETWORKS LLC

AI summary

The present disclosure provides a method of managing thermal loads in the powertrain of an electric vehicle and controlling various electronic components of a powertrain thermal management system. The method may include heating a coolant of a powertrain coolant loop utilizing waste heat from a liquid-cooled powertrain component (e.g., an electric motor, a DC-DC converter, etc.), measuring a coolant temperature, and utilizing combined feedforward and feedback control methods for different components (pump(s), radiator fan(s), valve(s)) of the powertrain thermal management system.