fuel heating through electromagnetic techniques in an ...€¦ · fuel heating through...

Fuel Heating through Electromagnetic Techniques in

an Engine Fuel Rail: Multiphysics FEM Analysis

EnginSoft

Andrea Serra

Giovanni Falcitelli

Emiliano D’Alessandro

Roberto Gonella

Magneti Marelli

Alfonso Di Meo

Nazario Bellato

Guilherme Alegre

Thomas Moura

Agenda

• Company profiles (EnginSoft S.p.A. and Magneti Marelli S.p.A.)

• The Magneti Marelli MECS (Microwave Ethanol Cold Start) project

• Microwave heating in a fuel rail through a FEM approach

a) Water heating

b) Ethanol heating

• Recent advances and a proposed solution

• Conclusions

• More than 34.000 employees

• 83 production units

• 12 R&D Centres

• 26 Application Centres,

• 18 countries in Europe, North and South America and Asia.

Magneti Marelli is an international Group committed to the design and production of hi-tech systems and components for

the automotive sector.

Automotive Lighting

PowertrainElectronic Systems

Suspension Systems

Exhaust Systems

Plastic Components and Modules

Motorsport

Magneti Marelli S.p.A.


Powertrain

Magneti Marelli Powertrain is Magneti Marelli business line dedicated to engines and transmissions components

production for cars, motorbikes and light vehicles.

850 MIO/€ of revenues, 4 applicative centres and 11 manufacturing sites, located in 4 continents.

Diesel System Trasmission

Motorbikes

BEV HEV

Multifuel System Gasoline System PFI

Gasoline System GDI


TELEMATIC BOX - The “telematic box” is an electronic control unit that can, at the same time, detect vehicle position and

operation data and send and receive information from outside the vehicle thanks to the GSM module.

INSTRUMENT CLUSTERS - The traditional business of this division, the instrument cluster provides drivers with information such

as speed, revs, fuel level and water temperature.

SYNAPTIC DAMPING CONTROL - An innovative oscillation damping system.

INFOTAINMENT AND TELEMATICS - For many years now, one of Magneti Marelli’s specific area of expertise is the development

and production of infotelematic systems, which are on board devices able to integrate entertainment (radio, music, etc.),

navigation, telematics, phone, connectivity, and much more.

THE OPEN-SOURCE PLATFORM GENIVI COMPLIANT - Magneti Marelli presented the first open-source platform for in-vehicle

infotainment devices.


AMT (Automated Manual Transmission) - A electro-hydraulic mechanism for automating manual transmission which derives from

Formula 1 which combines comfort of use with a reduction in consumption.

MULTIFUEL TECHNOLOGIES: FLEXFUEL SFS® E TETRAFUEL® - The TetraFuel® system enables a car’s engine to run on four different

types of fuel. This allows consumers to choose whether to refuel with petrol, alcohol/petrol, pure alcohol or compressed natural

gas.

KERS (Kinetic Energy Recovery System) - The KERS (Kinetic Energy Recovery System) it’s a system that turns mechanical energy

under braking into electrical energy that can be stored into devoted batteries.

THE FULL-LED TECHNOLOGY FOR AUTOMOTIVE LIGHTING - Magneti Marelli Automotive Lighting has developed in 2007 the

world’s first mass-produced full-LED headlamp, featured by more than 20 innovative concepts.

GASOLINE DIRECT INJECTION TECHNOLOGY (GDI) - An advanced injection system for gasoline engines that allow engine

downsizing, improved performances, and significant reductions in fuel consumption and emissions.

The Magneti Marelli MECS team

Brasilian team

Italian team

Alegre Guilherme Moura Thomas

Di Meo Alfonso Bellato Nazario

Engin Soft S.p.A.

8

MECS project - Motivation

• Ethanol is widely used in the South America as a motor

fuel, mainly as a biofuel additive for gasoline, especially in

Brazil.

• Ethanol engines present a problem to achieve enough

vapor pressure for the fuel to evaporate and spark the

ignition during cold start.

Traditionally, thermo-resistive heaters are used for

such applications, that are fully inside and partially

fill the injector block volume room. However

thermo-resistive heating is slow.

An attractive alternative solution to reduce heating time can

be represented by electromagnetic high frequency heating.

MECS PROJECT - Technical implementation

A typical fuel rail geometry consists of a main

cylinder closed at its ends.

A fuel entrance allows the fuel to be pumped in

the rail and a certain number of fuel outputs

that release fuel to the injectors.

MAGNETRON

Microwave heating could be performed by

connecting an electromagnetic wave source, like a

magnetron, to one or more rail ends.

Magneti Marelli S.p.A. MECS (Microwave Ethanol

Cold Start) project is based on research on this

topic .

MECS project - Numerical design flow

A design process flow was implemented in the ANSYS Workbench platform as a cascade of

electromagnetic (HFSS) and transient-thermal analysis.

HFSS FEM analysis

ANSYS Multiphysics FEM analysis

HFSS EM model – Geometrical model definition

Imported 3D model from a *.stp cad file

1. In order to allow wave propagation inside the

rail, its internal surfaces must be conductive

and they were chosen to be copper or

aluminum made.

2. At microwave frequencies both aluminum

and copper can be considered as very good

conductors (only surface currents).

3. Once the wave is generated inside the rail,

external parts are not relevant to the EM

analysis and they can be neglected.

4. The rail model can be model as PEC.

5. The inner model, originally the vacuum room

inside the rail, can be generated through

Boolean 3D operations.

3D geometry of the inner volume of the rail

HFSS EM model – Geometrical model definition

EXTERNAL PEC

In HFSS the problem region is the region in which the solution is generated. The problem region

encompasses an area that is just large enough to include the entire design, but no larger. The part not

occupied by objects is considered to be the background object. The background fills in any voids not

occupied by objects and it is defined as a perfect conductor.

For the rail problem the only inner geometry is enough

to perform the numerical analysis. Anyway, a non-zero

thickness coating was modeled around the inner fluid

for mechanical reasons.

The external coating was chosen to be

0.5mm thick and modeled as PEC to

reduce computational time.

EXTERNAL PEC

HFSS EM model – Electrical considerations

• The described rail can be considered as a cylindrical waveguide terminated on a short circuit.

• Injectors’ room represent short circuited stubs as well as the fuel-in gate.

Generally, is complex and, according to HFSS notation:

is the attenuation constant

is the propagation constant

If is real and waves can propagate

If cut-off

If is imaginary and waves can NOT propagate

Waveguides are “frequency selective” transmission

lines where an electromagnetic field can propagate

with a complex propagation constant equal to

(according to HFSS notation):

where:

is a function of the geometrical model

is the material permittivity

is the material permeability

HFSS EM model – Electrical considerations

Beyond the cut-off frequency, given by

an infinite number of field distributions

occur, namely TE (transverse electric)

and TM (transverse magnetic) modes.

Given an operation frequency, modes

overlap and concur in power

transmission.

First 9 propagating modes for a circular waveguide

(transverse electrical field)

HFSS EM model – Excitations

Wave port excitation

Expanded elements project manager window

Ports excitation amplitudes can be set as a post process parameter

Short circuit termination

Port, number of modes and post-processing port settings

HFSS EM model – Mesh

Around 250k tetrahedrons for the inner

material (water example).

INNER ELEMENT

HFSS EM model – Material definitionsWater is a pre-defined material of the ANSYS

HFSS library.

Water εr μr σ (S/m) tgδ

81 1 0.01 0.01

Ethanol dielectric properties were added to the HFSS

library by defining a new material, defined as it follows.

Ethanol electrical conductivity is ~0.

Frequency, GHz

ANSYS Mechanical modelSymmetric contacts between contact regions.

Set to 0° C.

Power load is assigned stepped

h = 11W/(m^2*°C)

Q = W/m^3 (imported from HFSS

and mapped on each element)

EM and thermal results - Water

Complex propagation constant

EM and thermal results - Water

Volume loss density inside the rail as a function of frequency, when different mode configurations are excited.

25 MODES ON 10 MODES ON

For a given operating frequency, to set up a correct EM-thermal model, it is important to

«switch off» all the non-propagating modes.

EM and thermal results – [email protected]

Electric field distribution inside the rail

Volume Loss Density inside the rail

Temperature inside the rail

EM and thermal results – Water@4GHz




EM and thermal results – Ethanol



EM and thermal results – Ethanol@4GHz




Ethanol heating issues – a case study

Ethanol has a complex permittivity. Thus, the propagation constant has always both real and imaginary parts, the latter

allowing some propagation.

On the other side, the propagation constant real part assumes high values and it introduces high attenuation in the “rail

waveguide”.

A modified model was defined with a new inner element,

making it equivalent to a coaxial cable structure.

Coaxial cable structures allow the propagation of the

fundamental TEM (Transvers ElectroMagnetic) mode,

without cut-off frequency.

Does a propagation condition with lower

attenuation exist?

Ethanol heating issues – coaxial structure analysis


EM analysis – coaxial structure [email protected]



Conclusions and future works

• Microwave propagation inside a cylindrical fuel rail.

• Water and ethanol heating study approach.

• Losses due to ethanol permittivity introduce high

attenuations.

• A “coaxial” is being studied and it will be topic for future

investigations.

• Mixtures of ethanol and benzene fuel (E85) will be modeled.

fuel heating through electromagnetic techniques in an ...€¦ · fuel heating through...

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