Cool Group presentation

23rd of November 2010

Functions

Leader/Organizer – AshanEditor – LiamTaking minutes - Mal

Task divison

Electrical: Ali: regen. braking, ultra-capacitors, choice, charging technology Liam: batteries, choice, charging, includes removable/fixed

batteries Ashan: control system, motor back up topic: wiring – safety, back up

Mechanical: Mal: suspension, inertia/handling, steering, cooling Joe: transmission, motor, drive, weight and dimensions Braking

Aero: Sam: general aero profile, fairing, variations in rider position Sunil: wheels/tyres, cooling, general aero profile

Timeline end of term - complete matrix of interaction; choice of software (Maple or not);

what inputs we require, how we are going to quantify and who needs to provide those inputs (all with respect to Matlab)

before Christmas – initial design, good understanding, clued up enough to be able to flexibly adjust the research to the design and different possibilities; decisions meeting; hopefully a report structure draft finished, text written; overall inter-phase in the Simulink (each of us can create a box, with equations, to drag and see what’s going on

beginning of term – the report structure and the rough introduction; we will need to know the framework, think how things are going to fit etc

middle Hilary - allocate ‘placeholders’ in your report – ex ‘this page is reserved for that, a picture is going to be here’ etc

end of Hilary - first draft, giving us the chance to refine it

Easter break – refining the draft, working on presentations

Writing the report

Best if everyone can send their bits to Liam as they work them, hence a space set up on Wiki for regular upload of the drafts – for back up and to create a working document.

Introduction (written by person with the inputs from everyone):– overview of what we want to achieve, – outline the team structure, – indicates how we coordinate,– might contain milestones, whatever phase of the reports we have accomplished; write it while you deliver

The report itself should contain different possible solutions in each area and reasoning for choosing the particular one.

Motorbike model

Motorbike model

Mechanical

Drivetrain. This depends heavily on location and number of motors,

ex. if one motor, situated in similar location to ICE in standard bike, we may only need one gear ratio, which can be achieved by the choice of chain, gears and the help of Simulink

Note: whit chain, we must consider the ‘squat’ effect

Mechanical

Frame: strong enough and light enough to meet our overall bike specificiations: get an initial guess of weight and dimensions based on initial component choices;

Frame stiffness and deflection to loading in different orientations could be tested by building a simple 3D frame SolidWorks model, with simple cross section data

Desired material: Aluminium alloy;

Frame could be shot pinned for fatigue resistance;

Mechanical

Braking: Electrical team will be working on a scheme for regenerative braking to recover kinetic energy, but this will not provide enough decelerating force, especially not in an emergency.

Therefore, either disc or drum brakes must be supplied to cover all the remaining braking force required to stop the bike within an acceptable stopping distance.

Mechanical

Cooling: what would be the expected temperature that batteries (and motor) will reach during exceptional operation?

Three options available:- Air cooling (light, simple, cheap)- Water cooling (higher specific heat capacity,

density and thermal conductivity, more efficient, reduces temperature difference)

- Oil cooling (higher boiling point than water, electric insulator)

Mechanical

Suspension and steering (adjustable): what will be the overall weight of the motorbike? defined mainly by the spring rate and damping Front: forks: telescopic/duolever or single sided? Back: shock absorbers: twin or mono? Swingarm: parallelogram/swinging fork/cantilever or

single sided? Coaxial steering? Tank slapper – steering damper? Brake dive – increasing the spring rate/compression

damping of the forks? (stiffer and less pleasant to drive) Wheel flop – adjusted amount of trail

Electrical

Battery vs Ultra-capacitor Shape, size, weight, number of elements capacity, electronic ratings (V, I, P) heating during usage and cooling requirements Charging

battery inside bike battery removed for charging regenerative braking (ultra capacitor)

flywheel direct charging via battery? (ultra capacitor) dynamo (ultra capacitor)

Electrical

Energy-Motor interface DC-DC conversion

network of batteries switched to parallel or series based on requirements

Control system turn throttle - how does it affect the energy storage +

motor systems Initial suggestion:

two sub-systems sharing a table listing available battery and

capacitor energy sources (possibly ranked by stored energy)

Electrical

Motor YASA size output spec e.g. mechanical power input requirements e.g. min/max

current/voltages gear compatibility (can it run with a

transmission? do we need a transmission? limits?)

Aerodynamics

The program to be used is Solid Works as it has all of the CFD software functions that we

are going to need.

It also allows to import and modify the existing designs.

Aerodynamics

Flow lines - Demo of oncoming air flow around a component at 20m/s that Sam happened to have already with no build errors (just a pump housing).

AerodynamicsPressure distribution of same example.

Red, yellow, green from high to low pressure.

Aerodynamics

Model imported from the internet, designed by someone else. (Haven't managed to make it work with the fluid stuff as there are build errors). There are also other models and a range of motorbike parts available.