CAR SCHEMATICS

1
THE BRUIN CAR UCLA
TESTING RESULTS Power System Equation t
(0.752 0.013) D Chemicals We react 40mL 2M
HCl and 40cm Mg ribbon to calibrate our car
reaction. We use a linear relationship between
distance and time in order to obtain our equation
and calculate what time the car needs to
stop. Slight temperature variations have little
effect on our equation. Our car performance is
affected by fuel cell consistency and
efficiency. Stopping System Equation
V (0.0908 0.0120) t (2.0129
0.8459) Chemicals We react
solution 1 and solution 2 and vary the volume of
0.05M Na2S2O3 in the iodine clock stopping
reaction. There is a positive linear
relationship between volume of Na2S2O3 and the
time it takes for the reaction to turn dark and
stop the car. Temperature slightly affects the
reaction.
Team members Jennie Pang, Jessica Ji, Jammie
Peng, Selma Lee, Bert Liu, David Chung, Connie
Cao, Bryce Kozuki, Yue Du, Erik Lee, Ryan
Chiengkul, Daniel Lee, Danny Hsieh, Katherine
Chen, Jerry Tsao, Andrew Chan, Cynthia Ma, Luke
Liao, Sandy Luk, Tracy Tang, Tracey Tsuma, Josh
Green, Helen Durand
CAR SCHEMATICS
DESCRIPTION
Power System
Fuel Cell Generates electric current to power the
car. Description Hydrogen gas flows into the
anode of the TekStak 5-cell, 4-W stack, while
oxygen gas from the surrounding air passes
through the cathode. In the anode, the hydrogen
fuel splits into positive hydrogen ions and
electrons. The semi-permeable polymer electrolyte
membrane allows only positive hydrogen ions to
flow through, and these ions combine with oxygen
gas in the air to create water vapor. Meanwhile,
the electrons flow into an external circuit to
create electricity to power the car.
Reaction Vessel 1 Contains the chemical reaction
between 2M HCl and Mg. Description 4 oz.
(120mL) wide-mouth glass jar with black urea cap
and PTFE seal from McMaster-Carr (Product ID
4239T32). Dimensions are 58 mm mouth OD, 2 3/8
base diameter, and height is 2 11/16. Lid has a
¼ OD tube-to-tube PVDF coupling (McMaster-Carr,
5533K522) that connects tube to the filter vessel.
Water Load Container Carries 0-500 mL water.
Fan Blows air to feed oxygen to fuel
cell. Description Computer fan allows for
constant forced air convection to fuel cell. It
is powered by a 9-V battery and controlled with a
switch.
Magnets Hold up Mg ribbon inside lid of reaction
vessel. Description The magnet above the lid and
the magnetic stir bar under the lid are used to
control when the Mg drops into the HCl to
initiate the reaction. PTFE-coated 1 /2 x 3/8
magnetic stir bar from Aldrich (Product
IDZ127094-1EA).
Filter Vessel Ensures that none of the
hydrochloric acid used in the power reaction
leaks into fuel cell. Description 6 oz. (180mL)
wide-mouth glass jar with black urea cap and PTFE
seal from McMaster-Carr (Product ID 4239T33).
Dimensions are 63 mm mouth OD, 2 5/8 base
diameter, and height is 2 11/16. Lid has two ¼
OD tube-to-tube PVDF couplings (McMaster-Carr,
5533K522). One coupling connects tubes to allow
gas flow from the reaction vessel to the filter
vessel. The other connects a hose to the fuel
cell. As the gas bubbles through the water,
hydrochloric acid can dissolve in the water and
this process purifies the hydrogen gas feed to
the fuel cell.
We power our car by reacting magnesium and
hydrochloric acid to produce hydrogen gas our
fuel cell uses the hydrogen to produce
electricity to power our motor.  We produce an
excess amount of hydrogen gas and rely on our
stopping mechanism to stop the car. Our stopping
mechanism is an iodine clock reaction with a
circuit consisting of a relay, LED, and
photoresistor.  The chemicals used in iodine
clock reaction are hydrogen peroxide, sulfuric
acid, sodium thiosulfate, potassium iodide, and
starch.
Switch Controls current in the circuit consisting
of the fuel cell, motor, and relay. Description
12-V lighted toggle switch (RadioShack , 275-706)
Motor Gears under car Converts electrical
energy into mechanical energy to move the
car. Description Motor (1.5-3V) and gear box
from Tamiya (Product ID 72003) are completely
enclosed with no exposed moving parts.
A hydrogen fuel cell generates an electric
current to power the car. A reaction of 2M
hydrochloric acid and magnesium produces the
hydrogen for the fuel cell Mg (s) 2 HCl (aq) ?
H2 (g) MgCl2 (aq) The hydrogen produced then
bubbles through distilled water in a 180 mL
filter chamber containing 120 mL water in order
to remove acidic vapor from and add moisture to
the hydrogen gas. Finally, the filtered hydrogen
gas enters the fuel cell to generate power for
the motor H2 (g) ½ O2 (g)? H2O (g) energy

• ENVIRONMENTAL
• SAFETY FEATURES
• Power System
• Our power system eliminates the need to use
  fossil fuels.
• The fuel cell emits only water vapor.
• PVDF couplings and PTFE seals on reaction and
  filter vessels are highly resistant to
  hydrochloric acid.
• Secondary containment prevents possible acid
  spillage.
• Magnetic stir bar allows entire reaction to be
  completely contained so no hydrogen gas is
  released to the surroundings.
• A filter vessel helps prevent hydrochloric acid
  from contaminating the fuel cell.
• Stopping System
• Conical polypropylene tube is highly compatible
  with iodine clock reaction chemicals.
• Electrical wiring is fully covered and
  insulated.

Stopping System
Reaction Vessel 2 Contains iodine clock
reaction. Description 50 mL Polypropylene
Conical Centrifuge Tube, which has excellent
compatibility with iodine clock reaction
chemicals. (BD, 352070)
Volume dependent on desired stopping time.
LED (Light-Emmiting Diode) Provides light for
photoresistor light is blocked when iodine clock
solution turns dark. Description 5mm
high-brightness white LED with maximum voltage of
3.6 V. Powered by two 1.5-V AAA alkaline
batteries connected with battery holder.
(RadioShack, 276-017)
Photoresistor Provides resistance for relay when
iodine clock reaction turns dark and no light is
detected from LED. Description Cadmium Sulphide
(CdS) photo cells. Current provided by 9-V
alkaline battery connected with fully insulated
snap connector. (RadioShack, 267-1657)
Syringe not shown Used to combine the two
initial iodine clock solutions. Description 60
mL BD syringe with BD Luer-Lok tip. Pipette
tip is inserted in syringe and sealed with Teflon
tape. (BD, 309653)
SPONSORS ACKNOWLEDGEMENTS We would like to
thank Dr. James Drake, Dr. Yi Tang, and Dr.
Harold Monbouquette for their advice and support.
We would also like to extend our appreciation to
our sponsors
Relay Stops car by opening fuel cell circuit when
iodine clock solution turns dark. Description
Fast response, 5-V DC coil voltage relay. Fuel
cell circuit switch within relay is opened when
photoresistor provides resistance. (RadioShack,
275-232)
Switches Controls current in LED and
photoresistor circuits. Description "2 Press"
Off-On momentary switches. (RadioShack,
275-1566)
Our stopping mechanism is based on an iodine
clock reaction, which consists of three
reactions H2O2 (aq) 3 I- (aq) 2 H ? I3-
(aq) 2 H2O (l) (slow) I3- (aq) 2 S2O32- (aq)
? 3 I- (aq) S4O62- (aq) (fast) excess I3- forms
a complex with starch, which turns the solution
dark The limiting reactant is sodium thiosulfate
(Na2S2O3). The more sodium thiosulfate we use,
the longer the reaction takes to turn dark. The
reaction vessel for the iodine clock solution is
located between a photoresistor and a LED. A
relay connects this iodine clock circuit with our
fuel cell and motor circuit. When the iodine
clock solution turns dark, it prevents light from
reaching the photoresistor. This causes the
photoresistor to increase the resistance in the
iodine clock circuit, which triggers the relay to
open the motor circuit switch and thereby stop
the car.
Chem-E-Car Team at UCLA Western Regional
Conference 2009