rapid concept design process for ev and hev, … concept design process for ev and hev, including...

Rapid Concept Design Process for EV And HEV, Including Fuel Economy Robustness

Barry JamesChief Technical OfficerSeptember 2015

© Copyright 2015Slide 2CONFIDENTIAL

Contents

• Strategy for Fuel Economy Improvements

• Case Studieso Reduction in losses through gear redesign in an HEV

o Concept Design tool for EV and HEV, with focus on robust fuel economy

• Summary – Capabilities available today


Strategy for Fuel Economy Improvements

• Reducing losses in the full driveline systemo Reducing frictional losses in mechanical power transmission

o Reducing losses in the power sources e.g. motors and ICE’s

• Fuel economy improvements must be ROBUSTo Must consider ….. Driving conditions, Temperature, Tolerances etc.

o Speed of simulation must permit this to take place

Romax European Summit 2011, 4th and 5th October / Frankfurt, Germany 4

SYSTEM APPROACH TO CONSIDER EFFICIENCY, NVH AND DURABILITY IN THE OPTIMISATION OF AN ELECTRIC ALL WHEEL DRIVE GEARBOX

Dr. Artur Grunwald Gear System Engineer GKN Driveline International GmbH

Barry James Chief Engineer TransportationRomax Technology Ltd.


Hybrid concept and application data• FWD application equipped with an electric rear axle

• FWD mode (disconnected)• Pure electric drive mode• All-wheel-drive (AWD) mode

• Nominal power 20kW• Input torque 200Nm• Output torque 1500Nm• Input speed 7500rpm• Total ratio 1 : 7.5 • Optimized for efficiency & NVH


Strategy for macro-geometry optimization for efficiency, NVH and durability

Bending Contact NVH Efficiency Bearings

Pressure angle αHelix angle βModule

Face width

= improvement= increase = deterioration


E-Drive efficiency test results of gearbox with improved gear sets

• Drive and coast (shown below) conditions measurements • Dynamic calibration and controlled test temperature• Confirmation of expected efficiency improvements

Example of efficiency improvement for recuperation condition (coast)

Reference Improved ∆

Concept Design tool for EV and HEV, with focus on robust fuel economy


ProtoDrive: Integrated Tool for the Rapid Concept Design of Hybrid Electric Vehicle Systems

Aim: An integrated software tool for the rapid concept design of hybrid and electric vehicles.

Consortium: An interdisciplinary team with expertise in all aspects of drivetrain design

Project activity:

• Efficiency models for the engine, transmission, and electric subsystems

• Integration of these subsystems into a drivetrain model

• Case studies based on end users’ requirements to demonstrate the value of the tool


Challenge 1: Studying all possible design variants

• Romax simulation scans across the spectrum of drivetrain designs from pure electric to pure conventional

• Speed is more important than modelling detail so long as accuracy is sufficient to determine trends

• Rapid whole-system simulation is needed to address the multiplicity of options at concept stage

conventional

Shar

e of

pow

erEV

mild hybrid

parallel

seriesrange-extender

power-splitmicro hybrid


Challenge 2: Designing for robust fuel economy

• Real-world fuel consumption can be 20-50% higher than manufacturer figures, and this discrepancy is increasing rapidly

• Legislative drive cycles are not representative of how people actually drive

• It is vital to consider real-world driving conditions early in the design process

From laboratory to road: A 2014 update of official and real-world fuel consumption and CO2emissions for passenger cars in Europe


Requirements for Simulation

• Speed o To look at different structures

o To look at different motor/ICE types

o To look at different driving conditions

• Appropriate accuracyo Trends/comparisons in efficiency more important than absolute values

in concept design


Measured result

Computed result

IPMSM and DC-AC inverter efficiency:

*Switching device:SEMIKRON IGBTSKM400GB12T4

Efficiency Map: Romax Simulation versus Test

• The machine parameters arederived within seconds


• The machine parameters arederived within seconds

• The traction machines (IPMSMs)are well-known for parameternonlinearities

Efficiency Map: Romax Simulation versus 3D FE


Drive cycle simulation in the time domain

+ +

Spee

d

Time

WLTP Artemis urban US06

Spee

d

Spee

d

Spee

d

Time Time Time


Romax approach to drive cycle simulation

+ +

Speed

Acc

eler

atio

n

WLTP Artemis urban US06

Adding further drive cycles does not increase the simulation time

The drive cycle is represented as a distribution of operating points.

Speed

Acc

eler

atio

n

Speed

Acc

eler

atio

n

Speed

Acc

eler

atio

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Verification of Simulation Method

• Simulations were run for a battery electric passenger car using the Autonomie time-domain simulation software and Romax simulation methods.

• The energy consumption trends were the same for individual drive cycles, and when varying parameters in the model such as mass and transmission ratio.

• Romax simulations ran at least 10 times faster than the time-domain model.

Romax(FTP)Romax(NEDC)


MAGSPLIT: Magnetic Power Split Technology for Parallel Hybrid Electric VehiclesProject: Co-funded by the UK Technology Strategy

Board under their Low Carbon Vehicles programme

Project partners: Magnomatics (lead), Ford Motor Company, Arnold Magnetic Technologies, Romax Technology

Duration: 2 years (2012-2014)

Aims:

• Optimise Magnomatics’ Magsplit transmission for use in the Ford C-Max Hybrid

• Design, manufacture and test a prototype Magsplit device


Concept Evaluation and Drive Cycle Sensitivity

• 2000 ratio variants, each with their own shift strategy, were created and analysed in 1 week

• Sensitivity to various drive cycles was completed for all designs, allowing the best (least sensitive) design to be selected


Summary: Proven Capability ready NOW

• Reducing losses in the full driveline systemo Reducing frictional losses in mechanical power transmission

o Reducing losses in the power sources e.g. motors and ICE’s

• Fuel economy improvements that are ROBUSTo Must consider ….. Driving conditions, Temperature, Tolerances etc.

o Rapid simulation, sufficiently accurate

rapid concept design process for ev and hev, … concept design process for ev and hev, including...

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