AT CAD Team/AT e-velomobile   

Back view from vehicle; combination of images (see below)

I first proposed an AT-velomobile based on the UBC Supermileage vehicle; as such I contacted the team there, see http://docs.google.com/View?id=dcwtr665_281dw8stzf5 ) The first idea was to only include pedal-based recharging for a electric engine. However, reflecting upon this, I changed the design with a new version (now called the "e-velomobile") to allow increased modularity. This would be useful as people in the developing world may not have enough financial capability to immediatly purchase an electric engine (or the material to build one themselves) to propel the vehicle. As such, the new version now allows them to start off by first installing the pedals, and possibly add the engine later.

[edit] Main construction charisteristics

As can be seen from the drawings, it is important to distinguish 2 main parts of the vehicle's main body. These are the shell, and the tubes. The tubes are the main attachment objects, and are the parts that carry the weight of all of the parts mounted unto the vehicle. The shell on the other hand, is simply a covering material that is placed on to protect the driver from the elements. The underground unto which the driver lays, would be another plate, rolling free on the tubes (lackable with pins), possibly springed (for shock absorption). This plate will also house the backsupport (increasable/decreasable in height). The shell itself thus not need to be strong enough to carry the driver, nor anything else (thus allowing the use of flimsy, lightweight materials). The shell will also be composed of 2 parts, with the front part being very curved (cone-like) so as to deflect most of the air, as well as to make sufficient room to allow the pedalling. This added space for the front shell is definitely required, since the pedalling would not be possible in the smaller compartment of the back shell (the entire shell is somewhat shaped to the body). The spacing between the tubes is irrelevant here, since the pedals would be placed between these; only the shell will be the limiting factor.

[edit] Propulsion system

Top view of velomobile (sketch)

Sketch showing propulsion system; note cross-view showing a semi-open (U-type) pipe shielding the chain from road dust, ... hereby increasing its lifetime

Sketch showing the cross-section

The propulsion system could be made up using regular bicycle parts and parts from e-bike kits. The first idea for the velomobile was to use a hub wheel drive (given that the back wheel should be a "single" wheel with 2 tyre surfaces. Manufacturers included ie Nine Continent, MIT's Senseable City Lab, ... ; see http://www.alibaba.com/product-gs/51285805/Manufacture_Electric_bicycle_Conversion_Kits_CE.html , http://green.autoblog.com/2009/12/17/reinventing-the-bike-wheel-with-the-copenhagen-wheel/

However, seeing that already a chain will need to be used (to connect the pedals into the system, using a system of implementation that allows some modularity; see "modes" below), and given that the 2 wheels shouldn't spin (to possibly allow the use of (emissionless) IC-engines, ...) a chain drive engine is now preferred. Manufacturers include Ecospeed, eLation eLectric systems, ... ^[1] More info at http://en.wikipedia.org/wiki/Motorized_bicycle#Power_sources

Note that although it is mentioned frequently that electric engines do not benefit from a gearbox, in practice this hasn't proven to be the the case with e-bikes. See http://elationebikes.com.au/motor_theory.htm

Note that perhaps some AT can be reused from the Suzuki Power Free motorized bicycle.

Note that the emissionless IC-engine wouldn't be generally be used, it could just be a possible alternative in the future, if the builder is already in the possession of an old lawnmower engine, and if we figure out how to improve the efficiency (using the UBC supermileage system). Note that in case the IC-engine is used, no additional starter engine (+ lead acid battery) would be present. Instead, starting will be done using the pedals.

[edit] Modes

Several modes can be selected with the controller, knowingly

• Mode #0: off; pedal-powered only
• Mode #1: on; pedaling + engine; pedaling is required, attaining a certain speed for the engine to kick on. Upon reaching a certain speed (ie 30 km/h), the engine kicks on and increases the speed to a set limit.
• Mode #2: on; engine + recharge pedaling; engine supplies a certain (settable) speed and the electrochemical battery is recharged by pedaling (user can himself choose how hard he wishes to pedal, the harder he pedals, the faster the recharging)
• Mode #3: on; engine + pedaling; engine supplies a certain (settable) speed which can then be increased by pedaling

Note: as can be seen above, regular electrically assisted biking isn't provided; the third option comes quite close to this, but the condition of attaining a certain speed first is added. This was done because regular electrically assisted biking can be dangerous to include if the user isn't used to using this vehicle mode. This because it requires the rider to put down quite some effort to pedal, and the engine power increases the speed, again requiring the rider to put down increased effort on observing the traffic situation. As 30 km/h isn't generally a speed a bicycle rider would attain at situations where it is difficult to manouvre (he will attain this speed only ie on clear paths/roads), the adding of this requirement for the engine to kick on will make the entire system a lot safer.

Note that the engine power itself can't be altered; instead the mode needs to be changed to reduce the speed, or it needs to be stopped with a button.

Note also that, in order to decrease the amount of buttons for the controller, only 3 buttons would be present, up, down and OK. For the setting of a speed, the general average would be shown which is then lowered or hightened using the buttons.

Finally, note that if possible, basic sulpheric acid-batteries can be used, rather than Li-Ion, Li-Cad, ... These would be cheaper, repairable and producable on-site. Also, there is less of a problem with the waste using these.

[edit] Specs

The rough m³ of battery space is about 0,15 m³ to 0,36m³, or about 9000Wh/11250Wh to 21600Wh/27000Wh of energy available (calculation 1--> 30 cm x 20 cm x 250cm = 150 dm³ --> x 60 to 75Wh/l (wikipedia source: http://en.wikipedia.org/wiki/Lead%E2%80%93acid_battery) --> makes 9000Wh/11250Wh.) (calculation 2 --> 30 cm x 40 cm x 300cm = 360 dm³ --> x 60 to 75Wh/l (wikipedia source: http://en.wikipedia.org/wiki/Lead%E2%80%93acid_battery) --> makes 21600Wh/27000Wh.)

I'm hoping that with this energy supply and a suitable electric engine, my final design could travel at least 70km/h (to allow highway-use), or if this is unachievable, at least 40-50 km/h. The batteries would at least need to last 5 years (comparable to a conventional car battery), and hopefully a little longer (given improved battery management, ie de-sulphination, correct temperature control, see Appropriate_use_of_lead-acid_batteries) Range would need to be at least 100km (hopefully 150 km or more; note that the vehicle is a hybrid similar to the C5, so not all power needs to come from the batteries alone). The range is important since it is intented as a medium-range vehicle.

[edit] Controlling of vehicle

The steering would be done using a steer, a brake (combining both a regenerative brake and a linear-pull bicycle brake), a gear shifter and an engine start/stop button. Also, a pump can be controlled (manually) to heighten/lower the frame with shell.

The steering would be done by using a variation on a steer used on David Gordon Wilson's Avatar2000 (see http://en.wikipedia.org/wiki/Avatar_2000). In particular, the steer is composed of a straight pipe, pivoting in the middle (below the rider), with standing pipes as handles and connected to the front wheel using cables. The handles for the steer are retractible to allow easy embarking of the vehicle and thus come out a of hole from the shell when not in use. Holes are also foreseen in the bottom of the shell to allow placing the steer inside the shell, and turning it during use. In regards to the shafts of the steer (as well as the wheel axle) appearingly going "trough" the battery and other parts of the vehicle: this is not so since several batteries will be used in a line behing each other. The shafts and axle will be placed in empty spaces between them.

[edit] Frame suspension

Basic construction; focus on frame suspension

Frame suspension close-up & heightener for frame

The schematics to the right show on how the frame is suspended using shock absorbers on the wheels. In order to decrease shocks (which might be stronger as no airfilled tyres are used; ie tyres are filled with rubber), a additional suspension system (at least for a velomobile) is foreseen. This suspension (coil springs) are placed between the seat and the frame.

[edit] Miscellanceous

Regular bicycle wheels won't be able to be used; this as the wheels need to be 1 m high; the highest bicycle wheels produced are nowadays only 70cm.^[2] Despite this however, local bicycle wheel makers would be able to produce a bigger wheel, and outfit it with tyres without air (plain rubber filling).

[edit] References

^{[3] [4]}

[edit] Notes

A alternative version could also be made, using a pneumatic motor