Low Emission Vehicle Propulsion 23-24: Coursework
September 2023 Page 1
UNIVERSITY OF SUSSEX
School of Engineering and Informatics Department of Engineering and Design
Engine Technology (H3051)
Coursework – Design Specification for Electric Vehicle (EV) with Range Extender Engine
Submission Deadline: See SussexDirect
Submission is via “Canvas Page/Assignment/Coursework” and “MATLAB Grader/LEV”.
Submission requirements: You will work on the coursework individually and it must be entirely your
work. You need to submit the following:
Coursework
report (pdf file)
The coursework report, which should be approximately 2000-2500 words along
with graphs and pictures. This must be submitted on Canvas.
Matlab code The matlab code you have used in the project must be submitted on Canvas and
for C2-P1 where indicated, must also submitted using the online Matlab Grader
tool (This is indicated with MG next to the available marks).
Simulink model The Simulink model must be submitted on Canvas
This coursework is worth 40% of the Module marks.
The coursework consists of three sections:
Research: You need to choose ONE topic out of the three and research to provide a short report of
up to 700 words to address the research questions.
Design and Development: You will develop MATLAB code and SIMULINK models to achieve
the objectives defined in the project. The results will be presented and analysed with up to 1500
words in your report and the developed materials will also be submitted as supporting documents.
Reflective report: Your report will also contain a short section of around 300 words reflecting your
learning curve throughout the coursework and how you would improve it if you would do it again.
Ref. Item Comments Mark
Breakdown
(out of 100)
C1 Research Clear and straightforward answers are provided to address the
research questions. Brief technical introductions to the operational
concepts, consider including sensors and their technologies along
with figures to illustrate the concepts.
25
C2 Design and
Development
(Project 1 and
Project 2)
The design criteria are met. The developed codes and models are
fully operational, and the results are valid. The results are
represented and compared using figures and tables. A brief but
clear analysis of the results is provided.
The MATLAB code for C2-P1 will be submitted and evaluated
using MATLAB Grader.
The SIMULINK model for C2-P2 will be uploaded to Canvas as
a zip file.
65
(C2-P1:35
C2-P2:30)
C3 Reflective Report You will clearly describe your learnt lessons from the coursework.
Also, you will explain your most challenging and useful activities.
10
Mark Allocation Guideline
0-39 40-49 50-59 60-69 70+ 80+
Work mainly
incomplete and
/or weaknesses
in most areas
Most elements
completed;
weaknesses
outweigh
strengths
Most elements
are strong, with
minor
weaknesses
Strengths in all
elements
Most work
exceeds the
standard
expected
All work
substantially
exceeds the
standard
expected
Low Emission Vehicle Propulsion 23-24: Coursework
September 2023 Page 2
C1: Research (700 words)
Vehicle propulsion systems have been developed to reduce emissions and improve efficiencies. In this
task you will research one of the following areas of technology.
Select ONE of the following topics, then answer the questions specified for the chosen topic:
Turbocharging Systems: Conduct research and compare different turbocharging technologies
including, wastegate turbochargers (WGT), variable geometry turbochargers (VGT) and
eBoosters. Explain how the turbocharger can be used to reduce emissions and discuss the
costs versus benefits of the VGTs and eBoosters over WGTs.
Electric vehicles: Research the different battery cell configurations including; cylindrical,
pouch and prismatic. Discuss the cost versus benefits of each cell type and how the different
cells affect battery and vehicle design choices.
Hydrogen propulsion systems: research different hydrogen-based technologies for
powertrains and compare the hydrogen combustion engines with fuel cells in terms of design
philosophy, advantages and disadvantages.
END OF C1
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September 2023 Page 3
C2: Design and Development (1500 words)
You will solve two separate design projects and report the results of the BOTH. For C2-P1 you will
evaluate your MATLAB code using the MATLAB Grader. The questions you should submit via
MATLAB grader have MG next to the available marks.
A. Project C2-P1
Introduction
Manufacturers are considering hybridization to meet their corporate averaged CO2 emissions and fuel
consumption targets. In the ‘Series’ configuration of hybrid powertrains, a small combustion engine,
called range extender, provides onboard recharging of batteries to extend the mileage. This
configuration is used in hybrid cars like Nissan Note and the BMW I3. Cost-Effective range extenders
are crucial for the success of hybrid cars which are more expensive than conventional cars.
Aim of the Project
You are a product planner and technical specialist for Powertrain Solutions Corporation which designs
and manufactures customised electric motors and engines for particular applications and sells these
bespoke powertrains for different types of vehicles.
Your Supervisor has provided you with a vehicle performance requirement (see in the attached file
LEV_Coursework_Student_Parameters.pdf). Your Supervisor has also supplied the high-level system
architecture and efficiencies (Appendix A) and engine BMEP and specific fuel consumption and
emissions maps (Appendix B).
Your task is to identify the engine, generator and motor sizes that meet the performance and emission
requirements and write a brief high-level powertrain specification recommending the most suitable type
of engine for the specified application.
Project Objectives (Individualised)
You are given (by Reg Number) a unique set of vehicle specification provided in
LEV_Coursework_Student_Parameters.pdf. The specification of each vehicle is their functional
requirements in terms of gradient capability, acceleration capability, top speed and emission targets for
the rated power condition.
The following parameters are the same for all students:
Tyre Radius = 35 (cm)
Rolling resistance force = 0.015 × (Newtons)
Ambient pressure = 1 (bar)
You will design the hybrid powertrain from the following four perspectives; vehicle functional
requireemnts, powertrain sizing, engine control and commercial aspects.
Combustion engine selection
1 Provide 2 reasons why a gasoline engine would be more suitable than a Diesel engine for this
application.
(2 Marks)
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September 2023 Page 4
Powertrain sizing:
2 Calculate the required electric motor power if it is the only power source to meet the requested
road grade in LEV_Coursework_Student_Parameters.pdf at 70 kph. Also, calculate the speed and
torque of the electric motor in this condition. Hint: Calculate the required power to maintain a
constant speed at the given gradient. Then calculate the motor speed and hence torque.
Remember efficiencies.
(3 Marks MG)
3 Calculate the size of an engine that can provide half of the power required by the motor to
maintain the vehicle speed of 70 kph over a road with the given road grade in
LEV_Coursework_Student_Parameters.pdf, whilst the engine runs at optimum BSFC. See
Appendix B for BSFC characteristics.
(4 Marks MG)
4 Size the required fuel tank for the car to be able to travel 300 km of the repeated WLTP drive
cycle (Class 3) with a 20 kWh battery if the BSFC of the range extender is running at a constant
BSFC of 220 g/kWh.
Hint 1: You will need to load in the WLTP test cycle from
http://www.unece.org/fileadmin/DAM/trans/doc/2012/wp29grpe/WLTP-DHC-12-07e.xls
and then use to calculate the vehicle speed and acceleration over the drive cycle.
Hint 2: Work out average energy consumption per km over the WLTP and use this to calculate
the range that can be provided by the battery (EV range), assuming no regenerative braking.
From the EV range, calculate the range to be provided by the range extender. Remember
efficiencies.
(5 Marks MG)
5 An alternative configuration for the range extender is to replace the combustion engine with a
fuel cell. The fuel cell has a hydrogen fuel tank operating at 70MPa and ambient temperature.
Assuming the fuel cell provides the same amount of electrical energy as the combustion engine
range extender and the overall efficiency of the fuel cell is 60%. For the same test conditions as
Q4, estimate the size of the hydrogen fuel tank in litres.
(4 Marks MG)
Engine control
6 Design a control logic, as a pseudo-code, to switch the engine on and offspecifying the conditions
when start and stop happens. Hint: You should think about noise and vibration, battery charge,
thermal management and driver annoyance. Pseudo-code can be in the form of a flow chart for
example.
(3 Marks)
7 Assuming an engine with a size of 0.6 litres running at 10kW, define a ‘cost function’ including
the engine emissions and fuel consumptions and calculate the optimum speed the engine should
run at. Describe how you might use this information to design the engine speed controller. Hint:
Plot Emissions (NOx, HC and CO) and Fuel Consumption of the engine providing 10 kW at
different speeds. Normalise the emissions and fuel consumption the maximum values (to give a
value between 0 and 1). Then create a cost function that is the sum of the normalized emissions
and fuel consumption and find out at which speed the minimum cost function is achieved.
Comment on whether one species is dominating the cost function and what you might do to
prioritise one species over another.
(6 Marks)
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September 2023 Page 5
Commercial aspects
8 Compare the cost of fuel with the cost of electricity and comment on whether the battery, fuel
tank or both should be smaller or larger to reduce the running costs. Take the electricity and fuel
prices from the file LEV_Coursework_Student_Parameters.pdf and assume the engine is running
at 230g/kWh. Hint: Calculate the cost of energy by either the fuel or electricity through the
electric motor (at its output shaft).
(5 Marks MG)
9 Describe how government policy has influenced the automotive market with a focus on how it
has affected EVs, PHEVs and Range Extenders. Hint: Consider the different incentives and look
at how this may have influenced sales figures.
(3 Marks)
Advice & Supporting Materials
Remember that the Range Extender engine (Appendix A) is completely disconnected from the wheels
and therefore can operate at any speed and torque that match the power requirements.
Appendix B has engine fuel consumption and emission maps.
END OF PROJECT C2-P1
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September 2023 Page 6
B. Project C2-P2
Introduction
In this project, you will use an example of the hybrid electric vehicle model available from Mathworks.
The example, named as ‘Hybrid Electric Vehicle Input Power-Split Reference Application’, simulates
vehicle for translational movement, gearbox, electric and conventional drivetrains, engine and hybrid
powertrain controllers, driver and environment. You can download the example into your machine by
typing autoblkHevIpsStart in the command terminal of MATLAB (see Guidelines.docx
available under Canvas Page/Units for more details). A complete simulation setup is provided with the
desired driving cycle and a driver along with controllers to follow a desired cycle. Figure 1 illustrates
the top-level architecture of the simulation environment.
Figure 1 The top-level design of the hybrid electric vehicle simulation example provided by
MATLAB/SIMULINK Model
The simulation example can be over a driving cycle and all required variables can be extracted.
Moreover, parameters of the vehicle, powertrain and environment can be changed, and the controllers
can be overridden by new ones. Therefore, this simulation environment provides a testbed for testing
new controllers over different driving cycles.
Aim of the Project
You are a software test engineer for Powertrain Solutions Corporation which designs and manufactures
customised ECU programs for hybrid electric vehicles.
Your Supervisor has provided you with the developed engine and hybrid powertrain controllers in
SIMULINK and asked you to investigate an initial test environment to evaluate the performance of the
controllers in terms of their effects on fuel consumption and emission levels. Also, the test environment
should be flexible enough to easily been reconfigured for different topologies and parameters.
You have already reviewed different available software and chosen SIMULINK because it has the
powertrain and vehicle dynamics toolboxes and you can easily use available examples to construct and
use a test environment for different components of your hybrid electric vehicle.
Your task is to explore the tool by illustrating the structure of the ‘Hybrid Electric Vehicle Input Power Split Reference Application’ example and plot requested comparative figures. You will change the
example by adding some more calculations and plotting features. You will also change the vehicle and
controller parameters to analyse the performance of the hybrid powertrain controller.
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Project Objectives
Each student is given by a unique vehicle specification provided in
LEV_Coursework_Student_Parameters.pdf, see second page in the file.
You will change the given model to:
1 Update the example model with your given parameters in
LEV_Coursework_Student_Parameters.pdf.
Hint: You need to explore the model and find the locations of each parameter before changing them.
(2 Marks)
2 Illustrate and discuss the operating region of the electric motor during the simulation period.
Hint: You need to export the efficiency map of the motor from the SIMULINK model to MATLAB. The
map is in terms of motor speed and torque. Then you need to add required blocks within the SIMULINK
model to calculate the motor efficiency and to export the motor speed, torque and efficiency to MATLAB
during the simulation period. Finally, you will plot the efficiency map of the motor overlaid by the
scattered operating points on it. The resulting overlay plot will be the basis of your analysis.
(6 Marks)
3 Illustrate and discuss the operating region of the engine during the simulation period.
Hint: You will follow the same procedure described for the electric motor but to bsfc, bsNOx, bsHC
and bsCO of the combustion engine of the hybrid powertrain.
(8 Marks)
4 Based on the results from the above objectives 2 and 3, analyse the performance of the hybrid
control module in terms of achieving the optimum efficiency of electric and conventional drivetrains,
as well as the optimum emission levels.
Hint: You will review the results and identify areas to improve the efficiencies and emissions.
(6 Marks)
5 Based on your analysis results from the above objective 4, tune the hybrid controller parameters
to improve performance (if possible) and discuss your findings.
Hint: You will modify values of the SOCTarget, SOCChrgFactor, the formula to calculate the SOCOpt
and EngOnCalc and the threshold of the AccelPed signal and repeat the above objectives 2-4 and
compare the results with the original ones. You will identify any potential improvements.
Hint: You should explore the model by finding where the parameters eg. SOCChrgFactor are located
and used. You should find a ‘state machine’. Right click on this and go to the library block:
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September 2023 Page 8
Then right click on the library block and select look under mask:
You should now see the state machine, double click on the operating modes to see the actual state
machine. Use this to understand how the controller is using the SCOChrgFactor and explain the logic
in your answer.
(8 Marks)
Advice & Supporting Materials
LEV_Coursework_Student_Parameters.pdf is available on Canvas. Please note that there are two pages,
one for each design and development project.
END OF PROJECT C2-P2
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C3: Reflective Report (300 words)
In 300 words, reflect on your learning outcomes by doing this coursework. You can describe:
What were some of the most interesting discoveries I made while working on this project
About the problem About myself About others
What were some of my most challenging moments and what made them so
What were some of my most powerful learning moments and what made them so
What is the most important thing I learned personally
When did I realize that I had come up with my final best solution
How do I feel the project relates to real-world situations and problems
Were my milestones and goals mostly met, and how much did I deviate from them if any
What did I learn were my greatest strengths My biggest areas for improvement
What would I do differently if I were to approach the same problem again
What’s the one thing about myself above all others I would like to work to improve
END OF C3
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Appendix A
Background & Basic Requirements
A Series hybrid vehicle transmits all its power to the wheels via the electric motor which draws its
energy from a battery pack. When the latter reaches a specified minimum charge, a remote
engine/generator is started which recharges the battery, providing power to the electric motor. The
engine drives the generator only; it is not connected to the vehicle wheels and therefore the engine can
be controlled to operate at any speed from 1000-6000rpm in your assignment.
As an example of a modern electric car, Figures A1-A4 show the BMW I3 electric car that has a range
extender option to increase the operational range beyond the battery energy.
Fig.A1 Rear-mounted Emotor & power electronics in BMW I3 chassis, viewed from the rear
Fig.A2 BMW I3 ~125kW/250Nm Emotor with power electronics removed
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Fig.A3 BMW I3 Emotor with range extender engine (viewed from the cabin)
Fig.A4: BMW I3, chassis, body, powertrain and 18.8kWh floor battery pack
Range Extenders only require the engine occasionally and then only for a “get home safely, in comfort
without any stress” basis. A typical range in electric mode can be up to 150 km and in engine mode an
additional 100km, dependent on the fuel tank size, terrain and operating speed.
Power flows in Series Hybrid Powertrains
Figure A5 illustrates the candidate topology for the series hybrid powertrains including the
components and the power flow through the powertrain.
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Fig.A5 Power flows in Series Hybrid Powertrains.
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Appendix B
The fuel consumption and emission maps of a 4-valve/cylinder spark-ignition range extender at
stoichiometric AFR are provided as Fig.B1-B4.
Fig.B1 BSFC Map
Fig.B2 BSCO Map
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Fig.B3 BSNOx Map
Fig.B4 BSHC Map
