Cool Group presentation

1. Cool Group presentation 23rd of November 2010

2. Functions • Leader/Organizer – Ashan • Editor – Liam • Taking minutes - Mal

3. 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

4. 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

6. 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.

7. Motorbike model

8. Motorbike model

9. 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

10. 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;

11. 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.

12. 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)

13. 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

14. 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)

15. 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)

16. 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?)

17. 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.

18. 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).

19. Aerodynamics Pressure distribution of same example. Red, yellow, green from high to low pressure.

20. 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.