Πυρφόρος shell eco marathon

Pyrforos 2015

Our vehicle gets adjusted every year to the safety requirements of the contest, while it simultaneously gets evolved and improved. Pyrforos 2, is a great achievement of our team in preparation for the contest of Shell Eco Marathon 2014 as it managed to incarnate successfully our expectations.

Our team pioneered among other teams because this year we designed and built every single part of the car from scratch

Starting from the engine, our team created an innovative permanent magnet motor, which proved to be advantageous. The design and construction of the new motor took place in the laboratory of electrical machines and power electronics.

Keeping in mind the power requirements of the new motor, the power electronics team, designed and implemented the DC / DC converter that optimally collects the power from the solar panels which are located permanently on the vehicle’s shell. Furthemore this team designed the dc / ac inverter which is responsible for providing the necessary power to the motor.

In addition to the changes and improvements described above, our team integrated an algorithm for automatic starting in order to save energy and a cruise control system so as to maintain constant speed during the race. One of the most notable additions of our new vehicle is the telemetry system that transmits in real time important metrics such as engine’s temperature, current speed and distance traveled as well as the instantaneous consumption of the vehicle.

Furthermore while the timeframe was limited, a group of engineers of our team managed to design and build the chassis, the shell of the car and the steering mechanism with minimal weight requirements, while always keeping in mind the safety of the driver, the flexibility and the ergonomics of the vehicle.

Motor features

16 pole sychronous motor with permanent magnets concetrated, fractional, non-overlapping, single-layer winding and unequal teeth distribution, integrated in the rear wheel of the vehicle

Nominal Values:
  • Torque: 7.5Νm
  • Rotation Speed: 300rpm
  • Power: 270W
  • Efficiency: >88%
Differences from the previous motor:
  • Optimized for the motor's operating point
  • Less weight
  • Smaller size
  • Lower power consumption
  • Aluminum shell
  • In wheel motor
Video from the design and assembly
 
Power electronics and solar panel

Power electronics and solar panel features

To provide power to the motor-wheel, we used three-phase power inverter made of integrated and discrete components mounted on a printed board.

Nominal values and main characteristics::
  • Input Voltage: 100V
  • Phase current: 30A RMS
  • Power consumption of the inverter during the race (15W)
  • Switches: 6 Power MOSFET with antiparallel diodes
  • Motor Drive: Sinusoidal Pulse Width Modulation (SPWM), switching frequency operation up to 8kHz.
  • Processor: Microchip dsPIC30F4011

Batteries features

For the construction of the battery pack, we used batteries from A123 of lithium-ion type. Every battery has a nominal voltage of 3,3 V and a capacity of 2,3Ah. Compared to last year’s hydrogen cell, the batteries have more advantages which are summarized below:

  • Less size, weight.
  • Fixed output voltage for a large range of load.
  • High efficiency (= output power/ charging power). Approximately 95% compared to the efficiency of the cell, 40 to 60%.

Solar Panel Features

For the solar panel we used monocrystalline frame which is flexible and quite lightweight, with efficiency that is exceeding 17%. The main features are:

  • Pmax=20W
  • Vp=20V
  • Voc=21.5V
  • Isc=1.15A
Mechanical features

We create an aluminum chassis with a front steering mechanism, designed in a CAD program, made from low weight aluminum (with the invaluable help of Roy Customs Art Metal Works). Also new wheel centers were tailored to the high performance bearings.

Nominal values:
  • Length of the Chassis: 1.9m
  • Weight of the chassis: 9kg
  • Vehicle’s Torsion Beam: 4m

The new shell was designed in a CAD program and cutted with CNC model with accuracy of 0,2mm. Construction embodiment using glass fiber and epoxy resin, using vacuum infusion technique.

Nominal values:
  • Length of the shell: 2.3m
  • Width of the shell: 0.87m
  • Shell’s Weight: 8kg
Video from the construction
 

Our vehicle gets adjusted every year to the safety requirements of the contest, while it simultaneously gets evolved and improved. Pyrforos 2, is a great achievement of our team in preparation for the contest of Shell Eco Marathon 2014 as it managed to incarnate successfully our expectations.

Below you can see the vehicles of previous years 

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