Page 1 WATER ELECTROLYSIS: HYDROGEN AS A FUEL By: Jeremy Vissers, Advisor – Dr. David Kraemer ABSTRACT The rising cost of energy in today’s society is creating demand for renewable energies and for more efficient energy demanding operations. In particular, the inconsistent prices and dwindling supplies of oil are generating a push on the automotive industry to create vehicles that either run on alternative energies, or are more fuel efficient. While the hydrogen fuel cell is being considered as one major form of alternative renewable energy, the fuel cell can actually be used to produce hydrogen fuel when we reverse the chemical process. Therefore, it is in our best interest to study this chemical reaction to explore ways of effectively obtaining hydrogen, and utilizing this fuel as a viable energy source in addition to using it in a fuel cell. Several different types of electrodes as well as electrolytes have been tested during the construction of an electrolytic cell in an attempt to maximize efficiency and minimize decomposition of cell components. Once the optimum combination is discovered, experiments are performed testing this hydroxyl fuel in applications which could decrease the fuel consumption of an internal combustion engine in a vehicle or piece of machinery. Utilizing a process like this would allow us to create and use the hydrogen upon demand, eliminating several safety concerns, and the problem of effectively storing the fuel. INTRODUCTION The rapid consumption of an energy source of finite supply will eventually result in an energy crisis. The expression “energy crisis” is often correlated with discussions based around discovering new or renewable sources of energy. Another aspect many fail to consider is the efficiency at which we consume energy. Many day to day operations responsible for vast amounts of yearly energy consumption are very wasteful. For example, a coal-fired power plant is approximately 32-38% efficient according to the United States Department of Energy and Environmental Protection Agency, operating year-round to supply the nation its electrical energy demands [1]. If such a process were improved to 40-45%, smaller amounts of coal would be required to meet the same demands. The intention of the hydrogen booster apparatus is to try and increase the efficiency of today’s ubiquitous internal combustion engine. The course of this project consists of building and testing the electrolytic cell, retrofitting the cell to the test vehicle, and making alterations to the vehicle control system while performing road tests.
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WWAATTEERR EELLEECCTTRROOLLYYSSIISS:: HHYYDDRROOGGEENN AASS AA FFUUEELL By: Jeremy Vissers, Advisor – Dr. David Kraemer
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The rising cost of energy in today’s society is creating demand for renewable energies and for more efficient energy demanding operations. In particular, the inconsistent prices and dwindling supplies of oil are generating a push on the automotive industry to create vehicles that either run on alternative energies, or are more fuel efficient. While the hydrogen fuel cell is being considered as one major form of alternative renewable energy, the fuel cell can actually be used to produce hydrogen fuel when we reverse the chemical process. Therefore, it is in our best interest to study this chemical reaction to explore ways of effectively obtaining hydrogen, and utilizing this fuel as a viable energy source in addition to using it in a fuel cell. Several different types of electrodes as well as electrolytes have been tested during the construction of an electrolytic cell in an attempt to maximize efficiency and minimize decomposition of cell components. Once the optimum combination is discovered, experiments are performed testing this hydroxyl fuel in applications which could decrease the fuel consumption of an internal combustion engine in a vehicle or piece of machinery. Utilizing a process like this would allow us to create and use the hydrogen upon demand, eliminating several safety concerns, and the problem of effectively storing the fuel. IINNTTRROODDUUCCTTIIOONN
The rapid consumption of an energy source of finite supply will eventually result in an
energy crisis. The expression “energy crisis” is often correlated with discussions based around
discovering new or renewable sources of energy. Another aspect many fail to consider is the
efficiency at which we consume energy. Many day to day operations responsible for vast
amounts of yearly energy consumption are very wasteful. For example, a coal-fired power plant
is approximately 32-38% efficient according to the United States Department of Energy and
Environmental Protection Agency, operating year-round to supply the nation its electrical energy
demands [1]. If such a process were improved to 40-45%, smaller amounts of coal would be
required to meet the same demands. The intention of the hydrogen booster apparatus is to try and
increase the efficiency of today’s ubiquitous internal combustion engine. The course of this
project consists of building and testing the electrolytic cell, retrofitting the cell to the test vehicle,
and making alterations to the vehicle control system while performing road tests.
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TTHHEEOORRYY At first glance, many feel this project is an attempt to violate the First Law of
Thermodynamics, which states: “Energy cannot be created nor destroyed, but only converted
from one form to another” [2]. Since the apparatus draws energy in the form of electrical energy
from the battery, whose charge is maintained by the alternator, which is driven from the engine,
it is a closed energy system. The electrical energy is converted to chemical energy in the form of
hydrogen and oxygen where it is combusted in the combustion chamber. Electrical transmission
through electronic control devices and wire pose resistances, resulting in electrical losses before
the energy reaches the electrolytic cell. Additionally, the efficiency of an electrolytic cell varies
greatly with design, as one of the project tasks was to develop the most efficient electrolytic cell;
however it is not near one hundred percent. How is this add-on feature useful?
Gasoline consists of more than 500 different hydrocarbon compounds and is not a pure
substance [3]. The different compounds have different properties, including vaporization
temperature and pressure, as well as ignition temperature and flame speed. In a running engine,
not all the gasoline burns in the combustion chamber. Some of the gasoline exits the cylinder
through the exhaust manifold, where it is burnt in the catalytic converter to reduce hydrocarbon
emissions out the tailpipe. During ignition at the beginning of the power stroke, a rapid pressure
rise in the combustion chamber forces gasoline into crevice volumes in other parts of the
cylinder. Near the end of the power stroke when the pressure in the cylinder drops, the gasoline
extracts from the crevices and is pushed out through the exhaust valve during the exhaust stroke.
This occurs because the pressure wave reaches the cylinder wall before the flame front. The
flame speed of gasoline is approximately 42 cm/sec, whereas the flame speed of hydrogen is
approximately 346 cm/sec [4]. The presence of hydrogen within the combustion chamber aids in
the flame propagation across the piston, resulting in more complete combustion of the gasoline.
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More complete combustion should decrease engine emissions, while increasing power output
(combustion efficiency). It is suspected the energy released as a result of the increased
combustion efficiency will exceed the energy required to operate the auxiliary system, yielding a
net output mechanical energy gain per volume of fuel consumed.
EEXXPPEERRIIMMEENNTTAATTIIOONN The heart and soul of the apparatus is based on the simple electrochemical process of
electrolysis, defined as the passing of electrical current through water [5]. To perform
electrolysis, one needs at least two electrodes, and an electrolyte. The electrode is any electrical
conductor that is placed in direct contact with the solution to transfer electrons to the electrolyte,
while the electrolyte can be any ionic solution. The combination of the electrodes, electrolyte,
and container/reservoir is referred to as the electrolytic cell. Throughout this project, two
different types of electrolytic cells were used, a wet-cell and dry-cell.
As stated earlier, electrolysis is a simple chemical process to perform; however when it is
intended to be performed efficiently, for extensive periods of time, at a high rate, without
deterioration, the term “simple” becomes more difficult to believe. Extensive testing was
performed with materials from graphite to steels, and electrolytes from salts to acids, to
determine an electrode/electrolyte combination that could fulfill the specifications. It was
determined the best electrode/electrolyte combination at this point is stainless steel electrodes
with potassium hydroxide (KOH) electrolyte. Theoretically, platinum electrodes would be ideal
due to its inert properties; however at approximately $1700 per ounce, using such a rare metal
simply is not economical [6].
Six prototype electrolytic cells were constructed throughout this experiment. Prototypes
one through five were all equipped with the same internal electrode arrangement. This
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arrangement is shown in Figures 1, 2, and 3 and consists of thirteen 22 gauge 304 stainless steel
Figure 1: Electrode Layout – Prototypes 1-5
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Figure 2: Electrode Layout - Prototypes 1-5
plates. The plate arrangement is as follows: + n n n n n – n n n n n +, where the “–” symbolizes a
negatively charged plate, the “+” symbolizes a positively charged plate, and the “n” symbolizes a
neutral plate.
The plates are positioned in such an arrangement for several reasons. The process of
electrolysis only requires approximately 1.5 volts of electrical potential to proceed. Since the
source voltage under which the apparatus will be operating is approximately 13.5 to 14 volts DC,
the cell is designed for this input. The five neutral plates between the two plates of voltage
potential give the electrolytic cell capacitor properties. A charge is induced on each side of each
neutral plate, and there exists a voltage drop across the gap from plate to plate. There are five
neutral plates, yielding six gaps. Although the voltage drop is not uniform across all of the gaps,
the average voltage drop across each gap is about 2.2 volts. This smaller voltage potential
between plate gaps yields an overall greater efficiency of the cell, which translates to less heat
generation. When a potential difference larger than the minimum required voltage is presented,
the excess potential energy is released in the form of heat. Besides wasting input energy to the
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cell, excessive heat generation can lead to vaporization of the electrolyte, which further
depreciates the cell efficiency. Although 2.2 volts exceeds the minimum required voltage, it
serves as a great potential because of two reasons: (1) The rate of electrolysis is directly
proportional to the current drawn by the electrolytic cell. To meet desired production rates, the
potential difference of 2.2 volts allows this with a weaker electrolyte concentration, (2) I have
found the efficiency of electrolysis peaks at an operating temperature of about 150 degrees F.
The heat generated by the 2.2 volt potential difference warms the electrolyte to a temperature
where the cell operates more efficiently, especially at colder
ambient conditions.
Prototypes one through five is referred to as a “wet-cell”
design because the electrode configuration is directly submerged in
the electrolyte solution. Prototype six is referred to as a “dry-cell”
because the electrodes are not submerged in a bath of electrolyte.
Rather, the parallel plates are spaced and sealed by a series of
gaskets, and the electrolyte is pumped through the cell. Similar
aspects of electrode placement, spacing, type, and configuration
from earlier prototypes are used in the design of this cell. The
significant difference between the dry cell and previous prototypes
is the exposure of the plate corners. In prototypes one through
five, the corners of the electrodes were submerged in the
electrolyte solution. Geometric properties of the plates combined
with electrical conductivity of the electrolyte causes a build-up of
charge at the corners of the plates, which has a detrimental effect
Figure 3: Electrode Layout – Prototypes 1-5
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on the cell efficiency, because of excess heat generation. The dry cell design eliminates these
inefficiencies by eliminating the corners of the electrodes.
The dry cell design and system layout can be seen in Figures 4, 5, and 6. The electrodes
are octagon shaped 18-gauge 316 stainless steel and the end pieces are 3/8” thick high density
polyethylene (HDPE).
The placement of the reservoir is vital to the operation of the dry-cell design. The static
head introduced by placing the reservoir above the electrode configuration, in addition to the low
density gas production within the cell, creates a pumping loop of liquid through the cell. This
also has an affect on the performance of the cell because it keeps the electrodes exposed to the
electrolyte. The moving solution removes the bubbles from the plates as soon as they form,
minimizing the amount of surface area consumed by bubbles sticking to the electrodes. If space
is limited, the reservoir can be placed below the plate configuration with the addition of a small
centrifugal pump to the system.
Figure 4: Dry cell electrolyser and system
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Figure 5: Dry cell electrolyser
Figure 6: Dry cell reservoir
The selected test vehicle is a 1992 Ford Taurus, shown in Figure 7. This vehicle is
chosen for various reasons: (1) the vehicle’s long range maintenance history is known, (2) the
engine is a healthy running engine despite its age, (3) room is available under the hood, and (4)
the economic value of the vehicle is significantly depreciated should something unexpected
occur during experimentation that causes significant damage. The vehicle is equipped with an
EFI 3.0 Liter OHV Vulcan V6 engine and a four-speed automatic transmission with overdrive.
The engine is rated at 145 horsepower at 4800 RPM, and 165 ft-lbs of torque at 3600 RPM [7].
The engine was introduced in 1986, and is still used by Ford today in some models of the Ford
Fusion and Mercury Milan. The engine has become very well-known for its durability and
reliability. The vehicle is also equipped with the OBD I diagnostic system, which allows
retrieval of engine codes with an analog voltmeter.
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Figure 7: Test vehicle - 1992 Ford Taurus The apparatus is installed under the hood in the engine compartment and is operated by a
switch within the cabin so the driver can easily disable and operate the vehicle without the
apparatus engaged. Before and after pictures of the engine compartment are shown in Figures 8
and 9. Experimentation was performed to determine the best cell to engine interface. After a
series of tests, the best arrangement was to integrate the electrolytic cell into the manifold
vacuum loop through the positive crankcase ventilation (PCV) valve. In this arrangement,
manifold vacuum pulls air through the cell, which aids in dispersion of the hydroxyl gas. An
additional PCV valve is added to the supply line of the cell to help avoid a flashback explosion in
the event the engine backfires.
The addition of the hydroxyl gas to the combustion chamber yielded a different response
than originally suspected. During initial testing, the vehicle seemed to operate normally, with
the exception of the occasional “check engine” light illumination. Additionally, the fuel
economy appeared to be rather unaffected, if anything made slightly worse. The “check engine”
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light illumination became more frequent as testing continued. After further investigation of this
issue, it was determined the vehicle diagnostic system was attempting to “correct” the operating
state of the vehicle. The feedback loop from the oxygen sensors were seen by the engine control
unit (ECU) as invalid. The oxygen sensors are small voltage generators which measure the
amount of oxygen in the exhaust manifold of the engine by comparing that to the oxygen present
in the environment surrounding the sensor [8]. A catalytic reaction takes place within the sensor
between the different oxygen concentrations, generating a small voltage. The ECU uses this
closed loop feedback voltage signal to control the pulse width on the fuel injectors to obtain
optimum fuel economy while minimizing tailpipe emissions. When the ECU receives an invalid
signal, it assumes the sensor is malfunctioning, and returns to “open loop” control, where it
illuminates the “check engine” light, uses inputs from the mass air flow (MAF) sensor, and refers
to the pre-determine fuel map programmed within its memory to control the fuel injectors.
The hydroxyl gas caused an increase in oxygen in the exhaust, yielding a “lean” signal
from the oxygen sensors. The ECU attempted to “correct” the reading by adding fuel; however
the reading still appeared to be invalid, sending the unit into open-loop. To fix this problem, the
ECU had to be corrected. To do this, a simple resistor circuit powered by two AA batteries was
constructed. The signals from the oxygen sensors were intercepted and routed across one of the
Figure 8: Engine compartment before modifications Figure 9: Wet-cell installed in engine compartment
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Figure 10: Oxygen sensor signal corrector
variable resistors in the circuit, adjusting the signal to an
acceptable value for the ECU to prevent open-loop
operation. This device, shown in Figure 10, is located
inside the glove compartment of the vehicle and is fully
adjustable. The addition of this device resulted in
noticeable results in fuel economy, and no noticeable
changes in performance were noted while operating the
vehicle.
The gas production rate of the electrolytic cell is
directly proportional to the current it consumes. By Ohm’s Law, the current drawn is dependent
upon the resistance of the cell, which is a function of not only the concentration of the
electrolyte, but also the temperature of the electrolyte. This variability in the output of the cell
required some sort of operator interface to provide control of cell activity. To control the current
drawn by the cell, pulse width modulation is used. A pulse width modulator (PWM), shown in
Figure 11, is a electrical device which is often used to
control motor drives, and generates a square-wave
signal of “on” and “off” signals at frequencies
ranging from 100-3000 hertz. The PWM control
varies the duty cycle of the power signal, which is a
ratio of the time “on” to the time “off.” This concept
is what allows the PWM to control the current drawn
by the cell.
The first five prototypes were not controlled Figure 11: 30 Amp pulse width modulator
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by a PWM. Geometrical properties of the electrode configuration did not allow control with a
PWM. When installed on the wet-cell, the apparatus would experience a large instantaneous
current spike, significant enough to blow the fuse on the circuit approximately thirty seconds
after initiation. Although a few attempts were made to try and correct this issue, the reason for
the current spikes remains unknown. For the first five prototypes, the activity of the cell was
monitored, but uncontrollable by the operator while driving. Careful calibration of these
prototypes was performed at installation. On the other hand, the dry-cell design yielded a much
better response to the PWM.
The dry-cell is installed in the same general vicinity of the engine compartment as its
predecessors, and is shown in Figure 12. Additionally, the PWM is used to control the dry-cell
activity from inside the cabin by the operator. Other connections and vehicle alterations from the
wet-cell installation remain consistent.
Considering the electrolysis of water is being performed, the temperatures associated
with the winter season have to be considered. The electrolyte freezing is not a problem; however
the physical property of water expanding when if freezes is a threat to the construction of the
cell, as this is the case in many instances when dealing with water in cold temperatures. With
Figure 12: Dry cell electrolyser installed in the engine compartment
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this in mind, it is necessary to prevent the electrolyte from freezing during winter’s coldest
temperatures. Allowing the electrolyte to turn slushy is deemed acceptable, however freezing
completely is something to be avoided to protect the structural integrity of the cell.
The perfect additive is capable of depressing the freezing point of the electrolyte without
disrupting the electrolytic reaction. Typical alcohols such as methanol, ethanol, and isopropanol
are considered as possibilities in addition to ethylene glycol, which is typically used in engine
coolant systems. After a long discussion with Scott Brielmaier, a former chemistry/physics
teacher, the list was narrowed to isopropanol and ethanol due to some possibly hazardous
reasons associated with methanol. Before testing was performed with either of these alcohols,
the physical properties of potassium hydroxide were considered. It was discovered that the
correct concentration of potassium hydroxide would depress the freezing point of the electrolyte
significantly lower than desired [9]. Figure 13 is a graph showing the relative freezing point of
potassium hydroxide at different concentrations on a mass percentage basis [9]. By increasing
the concentration (significantly) from what was previously being used (approximately 0.5% by
weight) to twenty percent by weight, the freezing point would be lowered to -11.2ºF (-24ºC).
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Figure 13: Phase diagram for different concentrations of KOH
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The ability to lower the freezing point by increasing the concentration, without any additives is a
great solution to the freezing problem, except it brought about a different problem. The
electrolyte of this concentration is extremely conductive, thus making the cell incredibly difficult
to control, even with a PWM.
Experimentation was performed with isopropanol to determine its potential as an additive
for the application. A thirty-eight percent solution of isopropanol in KOH had a freezing point
below -13º F, suggesting that isopropanol would meet specifications. Because of denaturing
regulations, ethanol is typically more difficult to purchase in a pure form. Isopropanol was
chosen as the additive due to its availability and relatively low cost compared to ethanol.
The test vehicle had 201,500 miles at the installation of the first prototype in May 2010.
The vehicle has operated in all Wisconsin extreme weather conditions from very hot and humid,
to blustery cold and windy. The vehicle odometer currently reads about 214,500 miles and still
operational with the latest dry-cell prototype.
RREESSUULLTTSS//EECCOONNOOMMIICCSS The vehicle was purchased in 2001 with 102,000 miles for $3100.00 and currently has
214,500 miles and retains a private party re-sale value of $800 as suggested by Kelly Blue book
[10]. Associated with devices of a similar stature, many are suspicious of the payback period of
such a gadget. The principal investment, as well as the heart and soul of the cell, are the stainless
steel components. Many of the other major costs associated with the construction of the
apparatus are summarized in Table I below. Prices on particular items vary with time for various
reasons including the basic laws of supply and demand.
Up to this point in testing, the electrolytic cell has shown an average increase of fuel
economy of approximately 15%. Baseline testing established an average fuel economy of the
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test vehicle to be about 27 miles per gallon over a period of approximately five months. After
the apparatus is installed, and the appropriate alterations are made to the engine control unit
(ECU) to accommodate the addition, the average fuel economy of the test vehicle is established
at about 30.5 miles per gallon. Numerous non-constant variables affect the fuel economy
throughout all testing; however efforts are put forth in attempt to hold many of these
Table 3: Payback period over a range of fuel prices with a 25% increase (Assuming a 27 mpg baseline)
Table 2: Payback period over a range of fuel prices (Assuming a 27 mpg baseline)
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In addition to saving one money at the pump, it is assumed that such a device will reduce
tailpipe emissions from a vehicle. It is yet to be confirmed or tested; however, plans exist to
make use of a chassis dynamometer and emission gas analyzer to experimentally determine the
impacts the apparatus has on tailpipe emissions and power output.
CCOONNCCLLUUSSIIOONN Energy crisis severity can be reduced substantially by increasing the efficiency at which
energy is consumed. If every passenger vehicle on the road achieved 50 miles per gallon of fuel
the amount of energy consumed per day would be decreased dramatically. Discovering new and
renewable sources of energy is important, but we must also work to develop ways to make our
processes more efficient. In this experiment, I took a vehicle with over 200,000 miles and
technology nearly twenty years old, and forced it to change its ways to make it run more
efficiently. Imagine the potential impacts such an apparatus could have on a vehicle with more
sophisticated diagnostics and an engine and ECU designed to operate with this add-on feature.
AACCKKNNOOWWLLEEDDGGEEMMEENNTTSS Scott Brielmaier – Hortonville High School Physics/Chemistry Teacher
James Hamilton, Ph.D. – University of Wisconsin Platteville Chemistry and Engineering Physics Department
RREEFFEERREENNCCEESS
[1] “Carbon Dioxide Emissions from the Generation of Electric Power in the United States.” United States Department of Energy and Environmental Protection Agency. U.S. Energy Information Administration. http://www.eia.doe.gov/cneaf/electricity/page/co2_report/co2report.html
[2] Moran, Michael. Shapiro, Howard. Fundamentals of Engineering Thermodynamics.