The document discusses methods of propulsion for cars, focusing on hydrogen fuel cells. It provides details on how hydrogen fuel cells work, including: 1) Hydrogen fuel cells convert hydrogen and oxygen into electricity and water through a proton exchange membrane. 2) In a hydrogen fuel cell, hydrogen ions pass through the membrane while electrons travel through an external circuit, powering a motor. 3) At the cathode, hydrogen ions and oxygen react to form water, completing the electrical circuit. The document then discusses testing of a hydrogen fuel cell car prototype, including graphs of distance traveled versus charge supplied under different mass loads.

2. Method of propulsion of car :
Fuel Cell: A fuel cell is a device that uses chemicals to create electricity.
You can think of a fuel cell as a battery, which is a device that
converts chemical energy to electric energy but there are two major
differences
1. A fuel cell converts reacting chemicals while a battery doesn’t.
2. Also the fuel cell doesn’t use up the electrodes(or metal
conductors inside them but the battery does ).
This means the fuel cell can be used for a longer period of time than
the battery, as long as the chemicals it uses are available.

3. Hydrogen Fuel Cell : It basically converts hydrogen and oxygen into electricity
and water, and vice versa. It is called a reversible PEM fuel cell. The
abbreviation PEM refers to the membrane that separates the hydrogen
and the oxygen sides. PEM stands for proton exchange membrane. A thin
foil made of special polymers serves as a membrane in the fuel cell and is
located in the membrane electrode assembly in the center of the fuel cell.
Reversible means that all processes can run in both directions. In other
words, the cell can operate as both a fuel cell to produce electricity and
water, or as an electrolysis device to split water into hydrogen and oxygen.
In addition to the PEM, the MEA contains two electrodes on either side of
the PEM. The MEA is sandwiched together with protective film, metal
plates rubber gaskets in a clear plastic housing and head tightly together
with four bolts.

4. An
Exploded View of the fuel cell

5. The two electrodes the cathode and the anode. The hydrogen side is the anode
and the oxygen side is the cathode. On the anode, electrically neutral
hydrogen molecules which come from the hydrogen tank split into
hydrogen ions and electrons with the help of a catalyst. The positively
charged hydrogen ions travel through the polymer membrane towards the
negatively charged cathode, while electrons travel through the circuit with
an electrical load ( motor ) from anode to cathode. These hydrogen ions or
protons are small enough to pass through the membranes small holes but
larger oxygen ions cannot. The metal plates in the fuel cell conduct
electrons from the anode through the circuit to the cathode. On the
cathode the hydrogen ions react with the oxygen molecules that come from
the oxygen tank and the electrons from the circuit to form water.

6. While it is necessary to put energy in splitting of water molecules during
electrolysis, now energy is released upon recombination of the ions. In this
way, an electrical voltage is produced across the fuel cell. If you connect an
electric load ( motor in our case) to anode and cathode the electric current
flows and motor runs. Since the conversion of hydrogen and oxygen takes
place catalytically. The electrodes themselves do not change in the chemical
reaction. The combustion is said to be “cold” as there are no flames
involved. Nevertheless some heat is generated and one can feel the
warming up of cell. Chemically the following reaction occurs :
Cathode : O2 + 4H+ + 4e-  2H2O
Anode: 2H2  4H+ + 4e-
Overall Reaction : 2H2+O2H2O

9. Water is filled in the storage tank located towards the back of the car with the fuel cell in the center and the
motor at the front. First the fuel cell is connected to a battery or a solar panel to produce hydrogen and oxygen
by electrolysis of water and stored in the containers located in the storage tank which are connected with the
pipe. Now this we disconnect the battery and connect the motor to the fuel cell to produce power which runs the
car .

10. The stopping mechanism for the car is to estimate the amount of
fuel needed. Severe testing of the car was carried out at various
possible conditions and the data was plotted in excel and
regressed to obtain equations from the graph. So by varying
the amount of charge supplied for splitting of water to the
amount of distance the car would travel was obtained. And this
was repeated with different amount of mass on the car. In the
following slides you can see the various curves obtained in MS
excel for different cases.

11. 45
40
35
30
25
Series1
Linear (Series1)
20
15 y = 7.4467x + 2.3208
R² = 0.7359
10
5
0
0 1 2 3 4 5 6

12. 45
y = 13.445x - 26.831
40 R² = 0.967
35
30
25
Series1
Linear (Series1)
20
15
10
5
0
0 1 2 3 4 5 6

13. 35
30 y = 8.5998x - 10.516
R² = 0.9362
25
20
Series1
Linear (Series1)
15
10
5
0
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

14. 35
y = 4.188x + 2.3424
30
R² = 0.9588
25
20
Series1
Linear (Series1)
15
10
5
0
0 1 2 3 4 5 6 7

15. 35
y = 5.0658x - 9.9868
30 R² = 0.9875
25
20
Series1
Linear (Series1)
15
10
5
0
0 1 2 3 4 5 6 7 8 9

16. Everyone has heard about global warming, the greenhouse effect, environmental pollution, smog. Many
people are concerned about the climatic changes and the toxic emissions into the air we breath. We
know that these effects are a result of our own human activities. Many people are engaged in
discussions of mitigating these negative impacts in the future. Several ideas for vehicular traffic and
energy production have been proposed. Today many scientist and engineers are turning these ideas
into reality. Fuel cells are thought of as an alternative source of energy. Hydrogen fuel cells are very
clean with no toxic emissions and very efficient. The only by product is water . But fuel cells don’t
generate energy out of nothing. They use hydrogen and hydrogen is an excellent carrier of energy.
Hydrogen is non toxic, renewable and easily obtainable. When it combusts with oxygen water is
formed. This water can again be split into hydrogen and oxygen and this process can be repeated
limitlessly without any emissions. With fuel cells you can very efficiently convert hydrogen into
current. Fossil fuels are converted into usable energy through combustion. The energy released is
inherently difficult to capture and inefficient . It also produces carbon dioxide which cannot be
converted into usable fuel. A fossil fuel engine in power plant is only about 30 – 40 % efficient.
Engines in car are even less efficient 15-20 % on the other hand fuel cells operate at 40-65%
efficiency. Experts even predict that with the efficiencies upto 75% are possible in the near future.

17. Efficiency = operating voltage/electrolysis voltage
=.95v /1.6v=.59
=59%

19. 1. Conceptually replacing oil based infrastructure with
hydrogen would cost a large amount of money.
2. Although hydrogen is abundant in the atmosphere, it still
has to be extracted (in our case electrolysis ) , currently the
process is cost prohibitive .
3. Storage of hydrogen onboard , gas can escape and may be
undetectable and it readily explodes.

20. Some Hydrogen fuel cell cars developed by Mercedes, Honda, BMW and
GM

21. Thank You