
A hydrogen internal combustion engine vehicle (HICEV) is a type of
hydrogen vehicle
A hydrogen vehicle is a vehicle that uses hydrogen to move. Hydrogen vehicles include some road vehicles, rail vehicles, space rockets, forklifts, ships and aircraft. Motive power is generated by converting the chemical energy of hydrogen to me ...
using an
internal combustion engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal comb ...
that burns
hydrogen fuel. Hydrogen internal combustion engine vehicles are different from
hydrogen fuel cell vehicles (which utilize hydrogen
electrochemical
Electrochemistry is the branch of physical chemistry concerned with the relationship between electrical potential difference and identifiable chemical change. These reactions involve electrons moving via an electronically conducting phase (typi ...
ly rather than through
oxidative
Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...
combustion
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion ...
). Instead, the hydrogen internal combustion engine is simply a
modified version of the traditional
gasoline-powered internal combustion engine. The absence of carbon means that no is produced, which eliminates the main
greenhouse gas
Greenhouse gases (GHGs) are the gases in the atmosphere that raise the surface temperature of planets such as the Earth. Unlike other gases, greenhouse gases absorb the radiations that a planet emits, resulting in the greenhouse effect. T ...
emission of a conventional
petroleum
Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term ''petroleum'' refers both to naturally occurring un ...
engine.
As pure hydrogen does not contain carbon, there are no carbon-based pollutants, such as
carbon monoxide
Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...
(CO) or hydrocarbons (HC), nor is there any carbon dioxide () in the exhaust. As hydrogen combustion occurs in an atmosphere containing nitrogen and oxygen, however, it can produce
oxides of nitrogen known as . In this respect, the combustion process is much like other high temperature combustion fuels, such as kerosene, gasoline, diesel and natural gas. Therefore, hydrogen combustion engines are not considered
zero emission A zero emission engine, electric motor, motor, process, or other energy source emits no waste products that pollute the environment or disrupt the climate.
Zero emission engines
Vehicles and other mobile machinery used for transport (over land, sea ...
.
History
In 1806,
Francois Isaac de Rivaz designed the
De Rivaz engine
The de Rivaz engine was a pioneering reciprocating engine designed and developed from 1804 by the Franco-Swiss inventor Isaac de Rivaz. The engine has a claim to be the world's first internal combustion engine and contained some features of modern ...
, the first internal combustion engine (ICE), which ran on a
hydrogen/oxygen mixture.
Étienne Lenoir
Jean Joseph Étienne Lenoir, also known as Jean J. Lenoir (12 January 1822 – 4 August 1900), was a Belgian-French engineer who invented the internal combustion engine in 1858. Prior designs for such engines were patented as early as 1807 (De ...
produced the
Hippomobile in 1863. In 1970, Paul Dieges patented a modified gasoline ICE which can run on hydrogen.
Tokyo City University has been developing hydrogen ICEs since 1970. They have recently developed a hydrogen-fueled bus and a truck.
Mazda has developed
Wankel engine
The Wankel engine (, ) is a type of internal combustion engine using an eccentric (mechanism), eccentric Pistonless rotary engine, rotary design to convert pressure into rotating motion. The concept was proven by German engineer Felix Wankel, f ...
s that burn hydrogen. The advantage of using ICEs such as Wankel and piston engines is that the cost of retooling for production is much lower. Existing-technology ICEs can still be used in conditions where fuel cells are not a viable solution as yet, for example in cold-weather applications.
In 1990 an electric
solar vehicle
A solar electric vehicle is an electric vehicle powered completely or significantly by direct solar energy. Usually, photovoltaic (PV) cells contained in solar panels convert the sun's energy directly into electric energy.
A concentrated ...
was converted to hydrogen using a 107 ml four-stroke engine. It was used in a research project which examined and measured losses from the power conversions sun → electricity → electrolysis → storage → motor → transmission → wheels. Compared to its previous battery-electric mode, the range proved higher but the system efficiency was lower, and the available
alkaline hydrogen generator was too large to be carried on board. It was powered by a stationary solar installation, and the hydrogen produced was stored in pressurised bottles.
Between 2005 and 2007,
BMW
Bayerische Motoren Werke AG, trading as BMW Group (commonly abbreviated to BMW (), sometimes anglicised as Bavarian Motor Works), is a German multinational manufacturer of vehicles and motorcycles headquartered in Munich, Bavaria, Germany. Th ...
tested a luxury car named the
BMW Hydrogen 7, powered by a hydrogen ICE, which achieved 301 km/h (187 mph) in tests. At least two of these concepts have been manufactured.
HICE forklift trucks have been demonstrated based on converted diesel internal combustion engines with
direct injection.
Alset GmbH developed a hybrid hydrogen system that allows vehicle to use petrol and hydrogen fuels separately or at the same time with an ICE. This technology was used with
Aston Martin
Aston Martin Lagonda Global Holdings PLC () is a British manufacturer of Luxury car, luxury sports cars and grand tourers. Its predecessor was founded in 1913 by Lionel Martin and Robert Bamford. Headed from 1947 by David Brown (entrepreneur ...
Rapide S during the
24 Hours Nürburgring
4 (four) is a number, numeral and digit. It is the natural number following 3 and preceding 5. It is a square number, the smallest semiprime and composite number, and is considered unlucky in many East Asian cultures.
Evolution of the H ...
race. The Rapide S was the first vehicle to finish the race with hydrogen technology.
Hydrogen internal combustion engine development has been receiving more interest recently, particularly for heavy duty commercial vehicles. Part of the motivation for this is as a bridging technology to meet future climate emission goals, and as technology more compatible with existing automotive knowledge and manufacturing.
In September 2022,
Kawasaki unveiled a hydrogen combustion engine developed using the same injector as the hydrogen Corolla, based on the
Ninja H2.
In May 2023,
Yamaha,
Honda
commonly known as just Honda, is a Japanese multinational corporation, multinational Conglomerate (company), conglomerate automotive manufacturer headquartered in Minato, Tokyo, Japan.
Founded in October 1946 by Soichiro Honda, Honda has bee ...
, Kawasaki and
Suzuki
is a Japanese multinational mobility manufacturer headquartered in Hamamatsu, Shizuoka Prefecture, Shizuoka. It manufactures automobiles, motorcycles, all-terrain vehicles (ATVs), outboard motor, outboard marine engines, wheelchairs and a va ...
received approval from Japan's
Ministry of Economy, Trade and Industry
The , METI for short, is a ministry of the Government of Japan. It was created by the 2001 Central Government Reform when the Ministry of International Trade and Industry (MITI) merged with agencies from other ministries related to economic acti ...
(METI) to form a technological research association called HySE (Hydrogen Small mobility & Engine technology) to develop hydrogen-powered engines for small mobility.
Records and motor sport
In the year 2000, a
Shelby Cobra
The AC Cobra, sold in the United States as the Shelby Cobra and AC Shelby Cobra, is a sports car manufactured by British company AC Cars, with a List of Ford engines#8 Cylinder, Ford V8 engine. It was produced intermittently in both the Uni ...
was converted to run on hydrogen in a project led by James W. Heffel (principal engineer at the time for the
University of California, Riverside
The University of California, Riverside (UCR or UC Riverside) is a public university, public Land-grant university, land-grant research university in Riverside, California, United States. It is one of the ten campuses of the University of Cali ...
CE-CERT). The hydrogen conversion was done with the aim of making a vehicle capable of beating the current
land speed record
The land speed record (LSR) or absolute land speed record is the highest speed achieved by a person using a vehicle on land. By a 1964 agreement between the Fédération Internationale de l'Automobile (FIA) and Fédération Internationale de M ...
for hydrogen powered vehicles. It achieved a respectable 108.16 mph, missing the world record for hydrogen powered vehicles by 0.1 mph.
In May 2021,
Toyota Corolla
The is a series of compact cars (formerly Subcompact car, subcompact) manufactured and marketed globally by the Japanese automaker Toyota Motor Corporation. Introduced in 1966, the Corolla was the best-selling car worldwide by 1974 and has bee ...
Sport, which is equipped with a hydrogen engine, entered the
Super Taikyu Series
Super Taikyu (スーパー耐久, ''Super Endurance''), formerly known as the Super N1 Taikyu Series prior to 2005 and N1 Endurance Series prior to 1995, and currently named the Eneos Super Taikyu Series Empowered by Bridgestone for sponsorship ...
race round 3 "NAPAC Fuji Super TEC 24 Hours", and completed the 24 hours race.
Toyota intends to apply its safety technologies and know-how that it has accumulated through the development of
fuel cell vehicle
A fuel cell vehicle (FCV) or fuel cell electric vehicle (FCEV) is an electric vehicle that uses a fuel cell, sometimes in combination with a small battery or supercapacitor, to power its onboard electric motor. Fuel cells in vehicles generate el ...
s and the commercialization of the
Mirai.
In November 2021, five automotive manufacturers in Japan (
Kawasaki Heavy Industries
is a Japanese Public company, public multinational corporation manufacturer of motorcycles, engines, Heavy equipment (construction), heavy equipment, aerospace and Military, defense equipment, rolling stock and ships, headquartered in Minato, To ...
,
Subaru
is the automaker, automobile manufacturing division of Japanese transportation conglomerate (company), conglomerate Subaru Corporation (formerly known as Fuji Heavy Industries), the Automotive industry#By manufacturer, twenty-first largest aut ...
, Toyota,
Mazda
is a Japanese Multinational corporation, multinational automotive manufacturer headquartered in Fuchū, Hiroshima (town), Fuchū, Hiroshima Prefecture, Hiroshima, Japan. The company was founded on January 30, 1920, as Toyo Cork Kogyo Co., Ltd. ...
and
Yamaha Motor) jointly announced that they will take on the challenge of expanding fuel options through the use of internal combustion engines to achieve
carbon neutrality
Global net-zero emissions is reached when greenhouse gas emissions and removals due to human activities are in balance. It is often called simply net zero. ''Emissions'' can refer to all greenhouse gases or only carbon dioxide (). Reaching net ze ...
, at the (three-hour) Super Taikyu race Round 6 held at
Okayama International Circuit
Okayama International Circuit (岡山国際サーキット), formerly known as TI Circuit Aida (TIサーキット英田) before 2005, is a private motorsport race track in Mimasaka, Okayama Prefecture, Japan
Japan is an island country ...
.
Their common view is that the enemy is not internal combustion engines, and that diverse solutions toward challenging carbon neutrality are needed.
At the event, Yamaha Motor unveiled a 5.0-liter V8 hydrogen engine which is based on
Lexus 2UR engine.
In June 2022, Toyota revealed the progress of its efforts in the Super Taikyu Series at the ENEOS Super Taikyu Series 2022. They say
cruising range was improved by approximately 20%, power output was improved by approximately 20% and torque was improved by approximately 30%. Also, hydrogen suppliers are added and its transporting became more efficient to support the race.
In July 2022,
Isuzu
, commonly known as Isuzu (, ), is a Japanese multinational automobile manufacturer headquartered in Yokohama, Kanagawa Prefecture. Its principal activity is the production, marketing and sale of Isuzu commercial vehicles and diesel engines ...
,
Denso
is a global automotive components manufacturer headquartered in the city of Kariya, Aichi Prefecture, Japan.
After becoming independent from Toyota Motor, the company was founded as in 1949. About 25% of the company is owned by Toyota. Despi ...
, Toyota,
Hino Motors
Hino Motors, Ltd., commonly known as Hino, is a Japanese manufacturer of commercial vehicles and diesel engines (including those for trucks, buses and other vehicles) headquartered in Hino, Tokyo. The company was established in 1942 as a corpora ...
, and Commercial Japan Partnership Technologies Corporation (CJPT) announced that they have started planning and foundational research on hydrogen engines for heavy-duty commercial vehicles with the aim of further utilizing internal combustion engines as one option to achieve carbon neutrality.
In August 2022, Toyota conducted demonstration run of GR Yaris H2, a special hydrogen-engine version of
Toyota GR Yaris, during the ninth round of the
World Rally Championship
The World Rally Championship (abbreviated as WRC) is an international rallying series owned and governed by the Fédération Internationale de l'Automobile, FIA. Inaugurated in 1973, it is the oldest FIA world championship after Formula One. E ...
(WRC) in
Ypres
Ypres ( ; ; ; ; ) is a Belgian city and municipality in the province of West Flanders. Though
the Dutch name is the official one, the city's French name is most commonly used in English. The municipality comprises the city of Ypres/Ieper ...
.
In May 2023, Toyota Corolla Sport, which is equipped with a
liquid hydrogen
Liquid hydrogen () is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecule, molecular H2 form.
To exist as a liquid, H2 must be cooled below its critical point (thermodynamics), critical point of 33 Kelvins, ...
engine, entered the
Super Taikyu Series
Super Taikyu (スーパー耐久, ''Super Endurance''), formerly known as the Super N1 Taikyu Series prior to 2005 and N1 Endurance Series prior to 1995, and currently named the Eneos Super Taikyu Series Empowered by Bridgestone for sponsorship ...
race round 2 "NNAPAC Fuji SUPER TEC 24 Hours Race", and completed the 24 hours race. It was the first time that a car running on liquid hydrogen has entered a race anywhere in the world.
In June 2023, Toyota unveiled a hydrogen race car "GR H2 Racing Concept" built for
24 Hours of Le Mans
The 24 Hours of Le Mans () is an endurance-focused Sports car racing, sports car race held annually near the city of Le Mans, France. It is widely considered to be one of the world's most prestigious races, and is one of the races—along with ...
.
Efficiency
The
thermal efficiency
In thermodynamics, the thermal efficiency (\eta_) is a dimensionless performance measure of a device that uses thermal energy, such as an internal combustion engine, steam turbine, steam engine, boiler, furnace, refrigerator, ACs etc.
For ...
of an ideal
Otto cycle
An Otto cycle is an idealized thermodynamic cycle that describes the functioning of a typical spark ignition piston engine. It is the thermodynamic cycle most commonly found in automobile engines.
The Otto cycle is a description of what happ ...
depends on the compression ratio and improves from 47% to 56% when this is raised from 8 to 15. Engines in practical vehicles achieve 50-75% of this, with about 60% is suggested as an unlimited-cost limit. However, a conference presentation by
Oak Ridge claims that the theoretical efficiency limit is 100%, based on it being an ''open cycle'' engine and therefore not limited by
Carnot efficiency
A Carnot cycle is an ideal thermodynamic cycle proposed by French physicist Nicolas Léonard Sadi Carnot, Sadi Carnot in 1824 and expanded upon by others in the 1830s and 1840s. By Carnot's theorem (thermodynamics), Carnot's theorem, it provides ...
. In comparison, the efficiency of a
fuel cell
A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen fuel, hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most bat ...
is limited by the
Gibbs free energy
In thermodynamics, the Gibbs free energy (or Gibbs energy as the recommended name; symbol is a thermodynamic potential that can be used to calculate the maximum amount of Work (thermodynamics), work, other than Work (thermodynamics)#Pressure–v ...
, which is typically higher than that of Carnot. The determination of a fuel cell's performance depends on the thermodynamic evaluation. Using hydrogen's
lower heating value, the maximum fuel cell efficiency would be 94.5%.
The efficiency of a hydrogen combustion engine can be similar to that of a traditional combustion engine. If well optimized, slightly higher efficiencies can be achieved. The comparison with a hydrogen fuel cell is interesting. The fuel cell has a high efficiency peak at low load, while at high load the efficiency drops. The hydrogen combustion engine has a peak at high load and can achieve similar efficiency levels as a hydrogen fuel cell. From this, one can deduce that hydrogen combustion engines are a match in terms of efficiency for fuel cells for heavy duty applications.
Efficiency decreases for small internal combustion engines. A 67 ml 4-stroke engine converted to hydrogen and tested with a
dynamometer
A dynamometer or "dyno" is a device for simultaneously measuring the torque and rotational speed ( RPM) of an engine, motor or other rotating prime mover so that its instantaneous power may be calculated, and usually displayed by the dyna ...
at the best operating point (3000 rpm, 14 NLM (normal liters per minute), 2.5 times stoichiometric air/fuel ratio) achieved 520 W and 21% efficiency. In order to measure the vehicular efficiency an also converted similar 107 ml engine (Honda GX110 with best gasoline efficiency 26%) was installed in a lightweight vehicle and driven up known gradients while measuring speed and hydrogen flow. Calculations gave as results 3.5% to 5.9% average efficiencies and 7.5% peak efficiency. The consumption measured on a level road was 24 NLM/km at a speed of 25 km/h and 31 NLM/km at 43 km/h.
Pollutant emissions
The
combustion
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion ...
of hydrogen with oxygen produces
water vapor
Water vapor, water vapour, or aqueous vapor is the gaseous phase of Properties of water, water. It is one Phase (matter), state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from th ...
as its only product:
:2H
2 + O
2 → 2H
2O
However, air is a mixture of gases, and the most abundant gas in air is nitrogen. Therefore, the combustion of hydrogen in air produces oxides of nitrogen, known as
. In this respect, the combustion process is much like other high temperature combustion fuels, such as kerosene, gasoline, diesel or natural gas. This problem is exacerbated by the very high temperatures generated by the combustion of hydrogen.
As such, hydrogen combustion engines are not considered
zero emission A zero emission engine, electric motor, motor, process, or other energy source emits no waste products that pollute the environment or disrupt the climate.
Zero emission engines
Vehicles and other mobile machinery used for transport (over land, sea ...
.
At the end of 2021, almost 96% of the global
hydrogen production
Hydrogen gas is produced by several industrial methods. Nearly all of the world's current supply of hydrogen is created from fossil fuels. Article in press. Most hydrogen is ''gray hydrogen'' made through steam methane reforming. In this process, ...
was from natural gas (47%), coal (27%) and oil (22%) and only around 4% came from electrolysis. Emissions from burning hydrogen can be negligible, but emissions from producing hydrogen are currently higher than direct combustion of the source.
Hydrogen has a wide flammability range (3%–70% H
2 in air) in comparison with other fuels.
As a result, it can be combusted in an ICE over a wide range of fuel-air mixtures. An advantage of this is the engine can be run using a lean fuel-air mixture: i.e., one in which the amount of fuel is less than the theoretical,
stoichiometric
Stoichiometry () is the relationships between the masses of reactants and products before, during, and following chemical reactions.
Stoichiometry is based on the law of conservation of mass; the total mass of reactants must equal the total m ...
or chemically ideal amount needed for combustion with a given amount of air. Fuel economy is then greater and the combustion reaction is more complete. Also, the combustion temperature is usually lower, which reduces the amount of pollutants (e.g. nitrogen oxides) emitted.
The
European emission standards
The European emission standards are vehicle emission standards that regulate pollution from the use of new land surface vehicles sold in the European Union and European Economic Area member states and the United Kingdom, and ships in European ...
measure emissions of
carbon monoxide
Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...
,
hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and Hydrophobe, hydrophobic; their odor is usually fain ...
,
non-methane hydrocarbons,
nitrogen oxides
In atmospheric chemistry, is shorthand for nitric oxide () and nitrogen dioxide (), the nitrogen oxides that are most relevant for air pollution.
These gases contribute to the formation of smog and acid rain, as well as affecting tr ...
(),
atmospheric particulate matter
Particulate matter (PM) or particulates are microscopic particles of solid or liquid matter suspension (chemistry), suspended in the atmosphere of Earth, air. An ''aerosol'' is a mixture of particulates and air, as opposed to the particulate ...
, and
particle number
In thermodynamics, the particle number (symbol ) of a thermodynamic system is the number of constituent particles in that system. The particle number is a fundamental thermodynamic property which is conjugate to the chemical potential. Unlike m ...
s.
As with any internal combustion engine, small amounts of the engine oil needed for lubrication can enter the combustion chamber, and take part in the combustion process. The exhaust gases can therefore contain small amounts of the products of combustion of this oil. Typically very minute quantities of CO, , , HC and particulates can be found in the exhaust gases. These are several orders of magnitude lower than what would be seen in the exhaust gases of a gasoline or diesel engine.
Tuning a hydrogen engine in 1976 to produce the greatest amount of emissions possible resulted in emissions comparable with consumer operated gasoline engines from that period. More modern engines however often come equipped with
exhaust gas recirculation
In internal combustion engines, exhaust gas recirculation (EGR) is a nitrogen oxide () emissions reduction technique used in petrol engine, petrol/gasoline, diesel engines and some hydrogen internal combustion engine vehicle, hydrogen engines. ...
(EGR). Equation when ignoring EGR:
:H
2 + O
2 + N
2 → H
2O + NO
x
This technology potentially benefits hydrogen combustion also in terms of emissions.
Since hydrogen combustion is not
zero emission A zero emission engine, electric motor, motor, process, or other energy source emits no waste products that pollute the environment or disrupt the climate.
Zero emission engines
Vehicles and other mobile machinery used for transport (over land, sea ...
but has zero
emissions, it is attractive to consider hydrogen ICEs as part of a hybrid powertrain. In this configuration, the vehicle can offer short-term zero emission capabilities, such as operating in city
zero emission zones.
Adaptation of existing engines
The differences between a hydrogen ICE and a traditional gasoline engine include hardened
valve
A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or Slurry, slurries) by opening, closing, or partially obstructing various passageways. Valves are technically Pip ...
s and
valve seats, stronger
connecting rod
A connecting rod, also called a 'con rod', is the part of a reciprocating engine, piston engine which connects the piston to the crankshaft. Together with the crank (mechanism), crank, the connecting rod converts the reciprocating motion of the p ...
s, non-platinum tipped
spark plug
A spark plug (sometimes, in British English, a sparking plug, and, colloquially, a plug) is a device for delivering electric current from an ignition system to the combustion chamber of a spark-ignition engine to ignite the compressed fuel/air ...
s, a higher voltage
ignition coil
An ignition coil is used in the ignition system of a spark-ignition engine to transform the battery voltage to the much higher voltages required to operate the spark plug(s). The spark plugs then use this burst of high-voltage electricity to ig ...
,
fuel injector
Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of a fuel injector. This article focuses on fuel injection in reciprocating piston and Wankel rotary engines.
All co ...
s designed for a gas instead of a liquid, larger
crankshaft damper, stronger
head gasket material, modified (for
supercharger
In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement (engine), displacement. It is a form of forced induction that is mechanically ...
)
intake manifold
An inlet manifold or intake manifold (in American English) is the part of an internal combustion engine that supplies the fuel/air mixture to the cylinder (engine), cylinders. The word ''manifold (engineering), manifold'' comes from the Old Eng ...
, positive pressure supercharger, and high temperature
engine oil
Motor oil, engine oil, or engine lubricant is any one of various substances used for the lubrication of internal combustion engines. They typically consist of base oils enhanced with various additives, particularly antiwear additives, deter ...
. All modifications would amount to about one point five times (1.5) the current cost of a gasoline engine. These hydrogen engines burn fuel in the same manner that gasoline engines do.
The theoretical maximum power output from a hydrogen engine depends on the
air/fuel ratio and fuel injection method used. The
stoichiometric air/fuel ratio for hydrogen is 34:1. At this air/fuel ratio, hydrogen will displace 29% of the combustion chamber leaving only 71% for the air. As a result, the energy content of this mixture will be less than it would be if the fuel were gasoline. Since both the
carbureted and
port injection methods mix the fuel and air prior to it entering the combustion chamber, these systems limit the maximum theoretical power obtainable to approximately 85% of that of gasoline engines. For
direct injection systems, which mix the fuel with the air after the intake valve has closed (and thus the combustion chamber has 100% air), the maximum output of the engine can be approximately 15% higher than that for gasoline engines.
Therefore, depending on how the fuel is metered, the maximum output for a hydrogen engine can be either 15% higher or 15% less than that of gasoline if a stoichiometric air/fuel ratio is used. However, at a stoichiometric air/fuel ratio, the combustion temperature is very high and as a result it will form a large amount of
nitrogen oxide
Nitrogen oxide may refer to a binary compound of oxygen and nitrogen, or a mixture of such compounds:
Charge-neutral
*Nitric oxide (NO), nitrogen(II) oxide, or nitrogen monoxide
* Nitrogen dioxide (), nitrogen(IV) oxide
* Nitrogen trioxide (), o ...
s (), which is a
criteria pollutant. Since one of the reasons for using hydrogen is low exhaust emissions, hydrogen engines are not normally designed to run at a stoichiometric air/fuel ratio.
Typically hydrogen engines are designed to use about twice as much air as theoretically required for complete combustion. At this air/fuel ratio, the formation of is reduced to near zero. Unfortunately, this also reduces the power output to about half that of a similarly sized gasoline engine. To make up for the power loss, hydrogen engines are usually larger than gasoline engines, and/or are equipped with turbochargers or superchargers. A small amount of hydrogen can be burned outside the combustion chamber and reach into the air/fuel mixture in the chamber to ignite the main combustion.
In the Netherlands, research organisation
TNO has been working with industrial partners on developing hydrogen internal combustion engines.
See also
*
Bi-fuel vehicle: a possible solution to overcome the lack of H
2 stations
*
Classic car fuel conversions
*
Fuel gas-powered scooter
A fuel gas-powered scooter is a Scooter (motorcycle), scooter powered by fuel gas. Fuel gases include such fuels such as liquefied petroleum gas (LPG), compressed natural gas (CNG), biogas and hydrogen (Hydrogen internal combustion engine vehicle, ...
*
Formic acid
Formic acid (), systematically named methanoic acid, is the simplest carboxylic acid. It has the chemical formula HCOOH and structure . This acid is an important intermediate in chemical synthesis and occurs naturally, most notably in some an ...
*
Hydrogen fuel enhancement
*
Home hydrogen fueling station
*
Liquid nitrogen vehicle
*
List of hydrogen internal combustion engine vehicles
*
Phase-out of fossil fuel vehicles
A phase-out of fossil fuel vehicles are proposed bans or discouragement (for example via taxes) on the sale of new fossil-fuel powered vehicles or use of existing fossil-fuel powered vehicles, as well the encouragement of using modal share, oth ...
*
Timeline of hydrogen technologies
This is a timeline of the history of hydrogen technology.
Timeline
16th century
* c. 1520 – First recorded observation of hydrogen by Paracelsus through dissolution of metals (iron, zinc, and tin) in sulfuric acid.
17th century
* 1625 – F ...
References
External links
EERE-Hydrogen internal combustion engine vehicle
{{DEFAULTSORT:Hydrogen Internal Combustion Engine Vehicle
Internal combustion engine
1807 introductions