Post on 16-Apr-2020
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
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• 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.
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
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Magneti Marelli S.p.A.
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.
Magneti Marelli S.p.A.
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.
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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 – Water@2.45GHz
Electric field distribution inside the rail
Volume Loss Density inside the rail
Temperature inside the rail
EM and thermal results – Water@0.8GHz
Electric field distribution inside the rail
Temperature inside the rail
Volume Loss Density inside the rail
EM and thermal results – Water@4GHz
Electric field distribution inside the rail
Volume Loss Density inside the rail
Temperature inside the rail
EM and thermal results – Ethanol
Electric field distribution inside the rail
Complex propagation constant
EM and thermal results – Ethanol@2.45GHz
Electric field distribution inside the rail
Volume Loss Density inside the rail
Temperature inside the rail
EM and thermal results – Ethanol@4GHz
Electric field distribution inside the rail
Volume Loss Density inside the rail
Temperature inside the rail
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
Complex propagation constant
EM analysis – coaxial structure analysis@2.45GHz
Electric field distribution inside the rail
Volume Loss Density inside the rail
EM analysis – coaxial structure analysis@0.4GHz
Electric field distribution inside the rail
Volume Loss Density inside the rail
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.