Integrated Magnetic Powersplit Advanced Control and Testing

Concept Design with IMPACT:Integrated Magnetic Powersplit Advanced Control and Testing

Dr Kathryn Taylor, Romax Technology12th September 2018

Slide 2 CONFIDENTIAL© Copyright 2018

Romax Technology is a leading global provider of integrated

software and services for geared and electrified driveline systems

Rotating Machinery eXperts…

Global presence with 240 employees across 13 offices in UK, USA, Europe, and AsiaOver 300 customers worldwide across a

range of industries including automotive, wind, aerospace, marine, rail, HDV

Nearly 30 years of engineering expertise -Consulting, engineering and support services


IMPACT: Integrated Magnetic Powersplit Advanced Control and Testing

Project aim:• To design, simulate, build, and test a magnetic

powersplit drivetrain for a hybrid passenger car. Romax activities:• Concept selection and detailed design

considering electromechanical interactions, with appropriate level of detail at each stage to balance simulation speed with required accuracy

• Dynamic analysis of the whole system to capture system effects and interactions between electrical and mechanical components

• Correlation of full system simulation models with test results for efficiency and dynamic behaviour


Magsplit Dedicated Hybrid Transmission

• Single input shaft; single output shaft; electronic ratio control• Magnetic interaction of input, output, and stator changes ratio of input/output• Magsplit replaces the planetary gearset and one motor/generator in a standard powersplit


Drive Cycle Simulation - Method• Statistical approach allows many drive cycles to be assessed

with no time penalty: urban, extra-urban, highway driving• Rapid simulation ideal for concept design: sensitivity studies

and fast simultaneous optimisation of vehicle parameters• Control strategy optimises powertrain operation for best

overall system efficiency and lowest fuel consumption• Minimises difference in battery charge across the drive cycle

PredictedMeasured

Efficiency maps for engine, Magsplit, traction machine, gears, power electronics, and battery• Minimum input data• Validated against test data


Drive Cycle Simulation - Sensitivity StudiesEffect on fuel consumption due to:• Drive cycle• Magsplit ratio/pole numbers• Overall ratio• Gear ratios• Vehicle mass• Control strategy• Traction machine efficiency• Gear efficiency• Battery efficiency


Drive Cycle Simulation - Sensitivity StudiesExample: Vehicle mass sensitivity

• Mass varied between 1500kg and 2100kg (nominal value 1800kg)

• Each additional 100kg gives a fuel penalty of 3%

Example: Magplit pole numbers

• Ratio sweep for different pole number combinations

• 6-10-4 performs better than the other options


Concept Evaluation – Cross-Platform Application• Components sized to meet performance requirements for acceleration and gradeability• Two vehicles: Eado (C-segment passenger car) and CS75 (C-segment Sports Utility Vehicle)• The Eado has two variants: entry level and sport

Propulsion mode HEV EVAcceleration target (kph)

0-50 0-100 0-50 0-100

Eado Entry-level 3.7 7.5 4 7Sport 5.25 11 12 15.5

CS75 3.7 9 4.8 12

Propulsion mode HEV EVGrade target 35% 20%


Concept Evaluation – Proposed Layouts• Six candidate concepts with different basic layouts, gearing, and clutch arrangements:

o Coaxial (traction motor and mcvt on same axis) vs. parallel (motor on separate axis)o 1-speed vs. 2-speed transmissiono Two options for position of selectable gear in parallel axis concepto Further option to clutch motor on parallel axis


Concept Evaluation – ConsiderationsCoaxial vs. parallel (motor on separate axis)• Coaxial is a simpler design with fewer parts, but the

traction machine is large so harder to package• Parallel has an extra gear stage so the traction

machine can be faster and smaller

Two-speed and clutched concepts• Lower fuel consumption, but additional

parts, mass, cost, complexity, risk• Allows the traction machine to be faster,

therefore smaller and easier to package• Trade-off between size of gears and

traction machine – higher ratio means smaller traction machine but larger gears

4

5

6

7

8

NEDC WLTP Artemis

Corre

cted

fuel

cons

umpt

ion

(litre

s/100

km)

coaxial 1-speed

coaxial 2-speed

Fuel consumption• Drive cycle simulations set up and run for all concepts

Durability calculations based on speed/torque operation points from drive cycle• Mechanical: gear rating duty cycles• Electromagnetic: thermal model


Concept Evaluation – Decision Matrix Method

• Design targets were identified and weighted• Candidates were ranked against all targets from 1 (worst) to 5 (best)• Candidate rank was multiplied by target weighting, and the total score

added up for each concept

Design targetsComponent efficiencyPackagingDurabilityDriveabilityThermalNoise & VibrationMassCostFuel consumptionManufacturabilityCross-platform applicationSafety/reliabilityEmissionsPerformanceTotal cost of ownership


Powertrain length is not acceptable for all applications

Concept Evaluation Results

Minimum cost, risk, and complexity

Vehicle performance is not acceptable for all applications

High torque means large selector mechanism with additional cost/mass/complexity

Opportunities Register: Added risk and cost for prototype stage


Final Concept

Magsplit

Engine

Final drive

Traction motor

Battery4

4.55

5.56

6.57

Baseline 5MT IMPACTdrivetrain

Fuel

cons

umpt

ion

[l/10

0km

]

• Drive cycle simulations indicate that the IMPACT drivetrain will meet the project target of 5 litres/100km on NEDC

• A fuel consumption benefit of around 22% on NEDC is expected compared to the baseline conventional 5MT vehicle, and there is potential to improve this further


Final Concept


Next StepsHardware and testing• Component procurement and assembly• Testing for efficiency, fuel consumption,

dynamic behaviour, thermal performance

Simulation• Dynamic simulation of whole powertrain with

Romax’s in-house dynamic simulation platformo An object-oriented multi-fidelity multi-

physics framework for dynamic analysiso Combines electromagnetic and

mechanical physics with a control system in the same mathematical framework

o Enables multiphysics simulation and analysis of steady state operating points, transient effects and mode changes

Documents

Integrated Magnetic Powersplit Advanced Control and Testing