Electric Machine Speed Oscillation for Vehicle Powertrain Heating

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Solution Overview

Problem

Cold starts and operation in low temperatures lead to increased power losses and reduced operational range in electric and hybrid vehicle powertrains, causing wear and requiring additional heating systems, which add complexity and cost.

Innovation Solution

A method where the electrical machine oscillates between two rotational speeds to generate heat, utilizing its inertia during fast acceleration and deceleration, eliminating the need for external heaters and allowing heating of the powertrain and subsystems without additional hardware.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If external heating systems (electric heater, fuel burner, heat pump) are used to heat the powertrain, then the powertrain can be heated effectively, but the device complexity and cost increase due to additional hardware

Engineering Contradiction:

Improvepowertrain temperatureVSAvoidheating system complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The electrical machine serves itself by generating heat through controlled oscillation between two rotational speeds. The control arrangement directs the electrical machine to oscillate between a first rotational speed and a second rotational speed, causing the machine to generate heat that is transferred to the powertrain and subsystems, eliminating the need for external heating systems.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The electrical machine performs multiple functions: it provides propulsion power when connected to drive wheels, and it generates heat for the powertrain when disconnected from the drive wheels. This multi-functionality allows the same component to serve both propulsion and heating purposes, reducing the need for dedicated heating hardware.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Device complexity

If the electrical machine oscillates between two rotational speeds to generate heat, then no additional heating hardware is needed, but the electrical machine must be disconnected from drive wheels or power take-off load

Engineering Contradiction:

Improveheating system complexityVSAvoidoperational availability

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The system dynamically switches between different operational modes based on vehicle needs. When heating is required, the electrical machine is disconnected from the drive wheels and oscillates between rotational speeds. When propulsion is needed, it reconnects and provides power. This dynamic operation allows the system to adapt to different operational requirements without permanent disconnection.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The electrical machine performs periodic oscillation between two rotational speeds during heating cycles. The control arrangement repeatedly connects and disconnects the electrical machine from the drive wheels, creating a periodic pattern of propulsion and heating operations that optimizes both vehicle performance and thermal management.

Inventive Principle:

Principle #19Periodic action

3Temperature

If the electrical machine oscillates between two rotational speeds to generate heat, then heat is generated effectively, but energy is consumed during the oscillation process

Engineering Contradiction:

Improvepowertrain temperatureVSAvoidenergy consumption

Core Design Contradiction:

TemperatureVSUse of energy by moving object

Solution Approach 1:

The system converts the energy that would be wasted during electrical machine oscillation into useful heat for the powertrain. Instead of dissipating energy as useless heat during acceleration and deceleration cycles, the control arrangement captures and directs this thermal energy to warm the powertrain and subsystems, turning a potentially harmful energy loss into a beneficial heating source.

Inventive Principle:

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

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 method effectively heats the powertrain and subsystems, improving performance and efficiency, reducing wear, and extending the operational range without adding complexity or cost, and can be used in various vehicle types, including BEVs and HEVs, even while in motion.

Implementation Method 1

heat is generated by the electrical machine using the inertia thereof during fast acceleration and deceleration of the electrical machine

Methodology Applied

Scientific EffectInertia: Inertia

Implementation Method 2

heat is generated by the electrical machine using the inertia thereof during fast acceleration and deceleration

Methodology Applied

Scientific EffectFriction heating: Friction

Data Source

PatentUS20250100391A1Method for heating a powertrain and/or subsystem of a vehicle and control arrangement configured to perform the method

Publication Date: 2025.03.27 SCANIA CV AB

AI summary

A method, performed by a control arrangement, for heating a powertrain and/or a subsystem of a vehicle. Said vehicle comprises an electrical machine configured to provide propulsion power to one or more drive wheels of the vehicle and/or power a power take-off load. The method comprises, when the electrical machine is disconnected from said one or more drive wheels of the vehicle and/or said power take-off load, controlling the electrical machine so as to oscillate between a first rotational speed and a second rotational speed to thereby generate heat.