This module enables students to develop computer simulations of engineering systems.
The course will take a case study approach and will make extensive use of simulation
software, specifically, Matlab and and the associated package, Simulink.
There will be an introduction to Matlab and Simulink for students who are not familiar with this software, there is some introductory material available in the module notes for MECH 337, Simulation of Dynamic Systems and this is a good place to look for an introduction to Simulink. Chapter 6 in the first reference, below, describes Matlab Simulink with examples of its use. Students should also note that there is extensive on line help available for Matlab version R2009a. A student version can be purchased.
The first session will introduce the module, discuss the assignment and provide an introduction to Matlab and Simulink, which is the software that will be used for the modeling.
During the following weeks the lecturer will explain the development of more complex and sophisticated models.
Specific time slots will be booked with students to help you to progress with the module.
NB: It is essential that students attend all the sessions and go through the work covered themselves on a weekly basis to ensure that it is clearly understood.
2. Assignment - Vehicle performance - Engine
N.B. This is an individual assignment.
i) Select a vehicle, ideally a car you have access to and one where you can obtain some documentation,
you will need to have values of:
b) Max. power and rpm at which this occurs.
c) Overall gear ratios.
d) Vehicle mass.
e) Radius of wheels.
f) The vehicle drag coefficient - this is only available for a limited number of cars, there is quite a bit of information available on the www, a reasonable guess is acceptable if you really are unable to find a value.
g) The frontal area of the car - this is used with (f) to determine the air resistance.
h) Measurements (to determine the cross section area) of the inlet tract at the throttle.
i) Diameter of the inlet valve, maximum lift of the inlet valve and the duration (in degrees of crank shaft rotation) that it is open.
ii) What you have to do
For your chosen / assigned vehicle you should develop a simulation model to
simulate it's velocity (for the first 10 seconds of its motion when the throttle is actuated
as shown in the diagram below:
This throttle position is simulated in Matlab Simulink by a 'Signal Builder' 'Source' block.
The model can be built using the Simulink blocks. For some aspects of the model,
eg pressure drops across the throttle plate and across the inlet valves, in addition to
trying to simulate these with Simulink, you should carry out some calculations using one or
more Matlab programs.
iii) Marking Scheme - The Report Must Include:
To ensure that you have a working simulation to submit it is vital that you start with a simple model of part of the system and get this working. Then develop the model a bit further and ensure it works and proceed in stages. Do NOT start straight away trying to build a complex model.
b) The equations used, detailed, properly described calculations and a graph (taken from Simulink) of car speed V time for the first 10 seconds of its motion - 30% of the marks.
c) A diagram of the final working Simulink model including, all values used and the purpose of each element and link in the model plus fully commented listing of the final Matlab program(s) developed - 10%
d) A CD containing the model (and Matlab programs) so I can run them to assess how it functions - 5%
e) A discussion about whether the velocity results from the simulation are believable and how you might improve them. (For a comparison with published data you should include the time taken for acceleration on full throttle 0 - 60 mph) - 25%
3. Due Dates:
NB: Students must meet with the lecturer as requested. You must bring your partly completed reports for discussion with the lecturer.
The final report must be submitted to the Faculty office by 1.00pm on Wednesday 24th March 2010.
4. References
'Mechanical Engineering Design Notes - Theme: Automotive Engines', by David Grieve, 2008, ISBN: 978-0-9560037-0-6.
'Bosch Automotive Handbook', 5th Ed., 2000, ISBN: 0-7680-0669-4
'The Motor Vehicle', by K Newton, W Steeds, T K Garrett, 9th Ed., Iliffe, 1972, ISBN: 0 592 00070 2
'Internal Combustion Engines - Applied Thermosciences', by C R Ferguson and A T Kirkpatrick, John Wiley and Sons, 2001, 2nd Ed., ISBN: 0-471-35617-4.
'Introduction to Modeling and Control of Internal Combustion Engine Systems', by L Guzzella and C H Onder, Springer, 2004, ISBN: 3-540-22274-x.
'Design and Simulation of Four Stroke Engines', by G P Blair, SAE, 1999, ISBN: 0-7680-0440-3.