Why hydrogen is considered the fuel of the future. Obtaining hydrogen as the fuel of the future

The modern automotive industry is developing with an emphasis on the production of more environmentally friendly vehicles. This is due to the worldwide struggle for purity. atmospheric air by reducing carbon emissions. The constant rise in gasoline prices is also forcing manufacturers to look for other sources of energy. Many leading auto-building concerns are gradually moving to mass production of cars running on alternative fuels, which in the very near future will lead to the appearance on the roads of the world enough not only electric cars, but also cars with engines powered by hydrogen fuel.

How hydrogen cars work

A hydrogen-powered car is designed to reduce atmospheric emissions of carbon dioxide, as well as other harmful impurities. The use of hydrogen to propel a wheeled vehicle is possible in two different ways:

• the use of a hydrogen internal combustion engine (VDVS);
• installation of a power electric unit operating from hydrogen cells (HE).

While we used to fill our car with gasoline or diesel fuel, the new miracle is powered by the most abundant element in the universe - hydrogen.

VVS is an analogue of the engines widely used today, the fuel for which is propane. It is this model of the engine that is easiest to reconfigure to work on hydrogen. The principle of its operation is the same as that of a gasoline engine, only liquefied hydrogen enters the combustion chamber instead of gasoline. A car with renewable energy is, in fact, an electric car. Hydrogen here is only a raw material for generating electricity needed to power an electric motor.

The hydrogen element consists of the following parts:

• corps;
• a membrane that allows only protons to pass through - it divides the capacity into two parts: anode and cathode;
• an anode coated with a catalyst (palladium or platinum);
• cathode with the same catalyst.

The principle of operation of VE is based on a physicochemical reaction, consisting of the following:

Thus, when the car is moving, no carbon dioxide is emitted, but only water vapor, electricity and nitric oxide.

Key Features of Hydrogen Cars

The main players in the automotive market already have prototypes of their products using hydrogen as fuel. You can definitely highlight the individual technical characteristics of such machines:

• maximum developed speed up to 140 km/h;
• the average mileage from one refueling is 300 km (some manufacturers, for example, Toyota or Honda, declare twice the figure - 650 or 700 km, respectively, on hydrogen alone);
• acceleration time to 100 km / h from zero - 9 seconds;
• power plant power up to 153 horsepower.

This car can accelerate to 179 km / h, and up to 100 km / h the car accelerates in 9.6 seconds and, most importantly, it is able to travel 482 km without additional refueling

Quite good parameters even for gasoline engines. There has not yet been a shift towards the VDVS using liquefied H2 or renewable energy vehicles, and it is not clear which of these types of engines will achieve the best technical characteristics and economic indicators. But today, more models of machines with an electric drive, powered by renewable energy, have been produced, which give greater efficiency. Although the consumption of hydrogen to obtain 1 kW of energy is less in the VDVS.

In addition, re-equipment of internal combustion engines for hydrogen in order to increase efficiency requires a change in the ignition system of the installation. The problem of rapid burnout of pistons and valves due to the higher temperature of hydrogen combustion has not been solved yet. Here everything will be decided by the further development of both technologies, as well as the price dynamics during the transition to mass production.

Pros and cons of cars running on hydrogen

Among the main advantages of hydrogen vehicles are:

• high environmental friendliness, which consists in the absence of most harmful substances in the exhaust typical for the operation of a gasoline engine - carbon dioxide and carbon monoxide, sulfur oxide and dioxide, aldehydes, aromatic hydrocarbons;
• higher efficiency compared to gasoline cars;

In general, the car has ambitions to conquer the whole world.

• less noise from the engine;
• lack of complex, unreliable fuel supply and cooling systems;
• the possibility of using two types of fuel.

In addition, air-powered vehicles have less weight and more useful volume, despite the need to install fuel tanks.

The disadvantages of hydrogen cars include:

• the bulkiness of the power plant when using fuel cells, which reduces the maneuverability of the car;
• the high cost of the hydrogen elements themselves due to the palladium or platinum they contain;
• imperfection of the design and uncertainty in the material for the manufacture of tanks for hydrogen fuel;
• lack of hydrogen storage technology;
• lack of hydrogen filling stations, the infrastructure of which is very poorly developed throughout the world.

However, with the transition to the mass production of cars equipped with hydrogen power plants, most of these shortcomings will certainly be eliminated.

Which hydrogen-powered vehicles are already in production

The production of machines for hydrogen fuel engaged in such leading global automotive companies as BMW, Mazda, Mercedes, Honda, MAN and Toyota, Daimler AG and General Motors. Among the experimental models, and some manufacturers already have small-scale ones, there are cars that operate only on hydrogen, or with the possibility of using two types of fuel, the so-called hybrids.

Such models of hydrogen vehicles are already being produced, such as:

• Ford Focus FCV;
• Mazda RX-8 hydrogen;
• Mercedes-Benz A-Class;
• Honda FCX;
• Toyota Mirai;
• MAN Lion buses city ​​bus and Ford E-450;
• hybrid car for two types of fuel BMW Hydrogen 7.

Today we can definitely say that, despite the existing difficulties (the new always makes its way with difficulty), the future belongs to more environmentally friendly cars. Autocars running on hydrogen fuel will compete with electric vehicles.

The popularity of electric vehicles has recently pushed cars into the background. fuel cells. Nevertheless, hydrogen is preparing to take the fight to electricity, and today we will look at the prospects of this element in the energy future of the planet. Hydrogen is the simplest and most abundant chemical element in the universe, accounting for 74% of all matter known to us. It is hydrogen that is used by stars, including the Sun, to release huge amounts of energy as a result of thermonuclear reactions.

Despite its simplicity and abundance, free form hydrogen is not found on Earth. Due to its light weight, it either rises to the upper atmosphere or combines with other chemical elements, such as oxygen, to form water.

Interest in hydrogen as an alternative energy source in recent decades has been caused by two factors. Firstly, pollution of the environment by fossil fuels, which is the main source of energy at this stage in the development of civilization. And second, the fact that fossil fuels are limited and estimated by experts to be depleted in about sixty years.

Hydrogen, as well as some other alternatives, is a solution to the above problems. The use of hydrogen leads to zero pollution, since the only by-products from the release of energy are heat and water, which can be reused for other purposes. Hydrogen is also very difficult to deplete, given that it makes up 74% of the matter in the universe, and on Earth it is part of the water, which covers two-thirds of the planet's surface.

Getting hydrogen

Unlike fossil energy sources (oil, coal, natural gases), hydrogen is not a ready-to-use source of energy, but is considered its carrier. That is, it is impossible to take hydrogen in its pure form as coal and use it for energy production, you must first spend some energy in order to obtain pure hydrogen suitable for use in fuel cells.

Therefore, hydrogen cannot be compared with fossil energy sources and a more correct analogy with batteries that must first be charged. True, batteries stop working after being discharged, and hydrogen cells can produce energy as long as they are supplied with fuel (hydrogen).

The most common and inexpensive method of producing hydrogen is steam reforming, which uses hydrocarbons (substances consisting solely of carbon and hydrogen). During the reaction of water and methane (CH4) at high temperatures, a large amount of hydrogen is released. The disadvantage of the method is that the by-product of the reaction is carbon dioxide, which enters the atmosphere in the same way as when burning fossil fuels, which, accordingly, does not reduce emissions. greenhouse gases despite the use of an alternative energy source..

It is also possible to use some natural gases directly in hydrogen fuel cells as an alternative. This makes it possible not to waste energy on obtaining hydrogen from gas. The cost of such fuel cells will be lower, however, when running on natural gas, greenhouse gases and other toxic elements will also enter the atmosphere, which does not make such gases a full-fledged replacement for hydrogen.

Hydrogen can also be obtained in the process of electrolysis. When an electric current is passed through water, it is separated into its constituent chemical elements, resulting in hydrogen and oxygen.

In addition to the usual methods, alternative ways of producing hydrogen are now being carefully studied. For example, in the presence of sunlight, the waste product of some algae and bacteria can also be hydrogen. Some of these bacteria can produce hydrogen directly from ordinary household waste. Despite relatively low efficiency This method, the ability to recycle waste makes it quite promising, especially given the fact that the efficiency of the process is constantly increasing as a result of the creation of new types of bacteria.

More recently, another promising method for producing hydrogen using ammonia (NH3) has appeared on the horizon. When this chemical is separated into its components, one part of nitrogen and three parts of hydrogen is obtained. The best catalysts for such reactions are expensive rare metals. The new method uses two available and inexpensive substances, soda and amides, instead of one rare catalyst. At the same time, the efficiency of the process is comparable to the most efficient expensive catalysts.

In addition to the low cost, this method is notable for the fact that ammonia is easier to store and transport compared to hydrogen. And at the right time, hydrogen can be obtained from ammonia simply by starting a chemical reaction. As yet unconfirmed predictions, the use of ammonia would make it possible to create a reactor with a volume of no more than a 2-liter bottle, sufficient to produce hydrogen from ammonia in quantities sufficient for use by a conventional-sized car.

Ammonia on this moment transported in large quantities and widely used as a fertilizer. It is this chemical that makes it possible to grow almost half of the food on Earth, and perhaps in the future will become one of the most important sources of energy for mankind.

Applications

Hydrogen fuel cells can be used in almost any form of transportation, in stationary power sources for homes, and in small portable, sometimes handheld devices, to generate electricity used by other mobile devices.

Back in the 70s of the last century, NASA began to use hydrogen to launch rockets and space shuttles into Earth's orbit. Hydrogen is also used later to generate electricity on shuttles, as well as water and heat as by-products of the reaction.

At the moment, the greatest efforts are aimed at promoting hydrogen as a fuel in the automotive industry.

Comparison of hydrogen and electric cars

Hydrogen at the philistine level is still considered to be a dangerous chemical element. This reputation was cemented after the crash of the Hindenburg airship in 1937. However, the US Energy Information Administration (EIA) claims that in terms of the use of hydrogen regarding unwanted explosions, this element is at least as safe as gasoline.

At the moment, it is obvious that if there is no next technological revolution, then the cars of the near future will be predominantly either electric, or hydrogen, or hybrid forms of these two technologies and gasoline cars.

Each of the options for the development of the auto industry has its own advantages and disadvantages. Filling stations for hydrogen fuel are much easier to make on the basis of current gasoline stations, which cannot be said about the infrastructure for the electric “charge” of vehicles.

In a certain sense, the division into hydrogen and electric cars is artificial because in both cases the machine uses electricity to move. Only in electric cars, it is stored in a more familiar form for us directly in batteries, and in fuel cells, a substance that, as a result of a reaction, will convert chemical energy into electrical energy, can be added at any time.

Refueling with hydrogen is comparable in time to refueling with gasoline, and takes several minutes, but the full charge of electric batteries is currently in best case produced in 20-40 minutes. On the other hand, electric cars have the advantage that they can be plugged into a power outlet directly at home, and if you do this at night, you can save on electric tariffs.

Environmental friendliness

Since neither electricity nor hydrogen are natural sources of energy, unlike fossil fuels, it is necessary to spend energy to obtain them. The source of this energy becomes a decisive factor in the environmental friendliness of both hydrogen and electric cars.

To produce hydrogen, either heat or electric current is required, which in hot and sunny regions of the planet can be obtained by collecting solar energy. In colder countries, such as Scandinavia, the emphasis is already on a more suitable source of green energy for this climate, on wind farms, which can just as well take part in the production of hydrogen using electrolysis. It is noteworthy that hydrogen in this case can also be used to store unused energy, for example, when generating at night.

Given the obligatory stage of obtaining hydrogen and electricity, the zero emission level of such cars depends on how the primary energy was obtained. That is why parity is observed between both types of vehicles and none can be considered more environmental remedy movement.

A draw can also be stated by comparing the noise level of these modes of transport. Unlike traditional ones, the new engines are much quieter.

On this occasion, we can recall the famous red flag law governing the appearance of the first cars in the 19th century. According to the most stringent forms of this law, a vehicle without horses could not move within the city at a speed exceeding 3.2 km / h. At the same time, anticipating the movement of the car a few minutes before its appearance, a person with a red flag had to walk along the road, warning about the appearance of transport.

The red flag law was passed due to the fact that the new vehicles moved relatively silently compared to carriages and could cause accidents and injuries, at least according to the judges of the time. The problem, although it was exaggerated, but after a century and a half, we can witness new similar laws due to the noiselessness of new types of engines. Electric cars and fuel cell cars are unlikely to be louder than the first vehicles, but the speed of their movement in urban areas is now clearly above 3 km, which makes them potentially dangerous for pedestrians. In the same Formula 1, they are now thinking about amplifying the sound of engines with the help of artificial voice acting. But if in auto racing this is done to increase entertainment, then in new cars the appearance of an artificial source of noise can become a safety requirement.

Negative temperatures

Fuel cell vehicles, just like conventional ones petrol cars, experience certain problems in the cold. The batteries themselves may contain a small amount of water, which freezes at low temperatures and renders the batteries inoperable. After warming up, the batteries will work normally, but at first without external heating, they either do not start, or work for some time at reduced power.

Travel range

Travel distance of modern hydrogen cars is approximately 500 km, which is noticeably more than in typical electric cars, which can often only travel 150-200 km. The situation changed after the advent of the Tesla Model S, but even this electric car is able to travel without recharging for a distance of no more than 430 km.

Such figures are quite unexpected if we take into account the efficiency of the corresponding types of engines. For conventional gasoline internal combustion engines, the efficiency is approximately 15%. The efficiency of fuel cell cars is 50%. The efficiency of electric vehicles is 80%. General Electrics is currently working on fuel cells with 65% efficiency and claims that their efficiency can be increased to 95%, which will allow storing up to 10 MW of electrical energy (after conversion) in a single cell.

Weight of batteries and fuel

However weak point electric cars are the batteries themselves. For example, in the Tesla Model S, it weighs 550 kg, and the total weight of the car is 2100 kg, which is a couple of hundred kilograms more than the weight of a similar hydrogen vehicle. The weight of this battery also does not decrease as the distance is covered, while the fuel used in gasoline and hydrogen car x gradually makes the car lighter.

Hydrogen elements also win in terms of energy storage per unit mass. In terms of energy density per unit volume, hydrogen is not so good. Under normal conditions, this gas contains only a third of the energy of methane in the same volume. Naturally, hydrogen is stored during transportation and inside fuel cells in liquid or compressed form. But even in this case, the amount of energy (Megajoules) in one liter loses to gasoline.

The strengths of hydrogen appear when you convert energy per unit weight. In this case, it is already three times higher than gasoline (143 MJ/kg versus 47 MJ/kg). Hydrogen also outperforms electric batteries in this indicator. At the same weight, hydrogen has twice as much energy as an electric battery.

Storage and transportation

Certain difficulties also arise in the storage of hydrogen. The most efficient form for transporting and storing this chemical element is the liquid state. However, it is possible to achieve the transition of gas into a liquid form only at a temperature of -253 degrees Celsius, which requires special containers, equipment and considerable financial costs.

2015

Toyota, Hyundai, Honda and other automakers have been investing heavily in hydrogen fuel cell research for years, and in 2015 they are set to introduce the first cars with a cost and performance that will make them an alternative to other modes of transport. The fuel cell car in 2015 must be a mid-size 4-door sedan with the ability to cover at least 500 km without refueling, which will last no more than five minutes. The cost of such a car should be in the range of $50 thousand to $100 thousand. Thus, the cost of hydrogen cars has decreased by an order of magnitude within one decade.

As should be obvious from the list of automakers, Japan will be one of the centers for the development of hydrogen cars. It is interesting that one of the main markets for these cars will be the territory separated from Japan by much greater distances than the nearby Asian market.

California has long had a reputation for being one of the most progressive places on planet Earth. This is where legislation often gives the green light. the latest technologies and inventions. The promotion of alternative fuel vehicles was no exception.

According to adopted law O vehicles with zero emission (ZEV - zero-emission vehicle) by 2025, 15% of all cars sold should not produce harmful emissions in atmosphere. Together with 10 other states that passed similar laws, there should be about 3.3 million ZEVs on US roads by 2025.

Despite the fact that preparations for the launch of new car is coming in full swing, in the early stages, manufacturers will have to face serious infrastructural problems. Toyota has committed $200 million to build hydrogen gas stations in California, but the money will be enough to build only 20 gas stations next year. Even without taking into account the high cost of construction, the number of gas stations will increase at a fairly modest pace. In 2016, their number will be 40 pieces, and in 2024 - 100 pieces.

Such a measured construction time can be easily explained by the fact that it is almost impossible to carry out even a small technological revolution in one year. 2015 is marked on the calendar as the start of the development of the hydrogen auto industry, however, fuel cell cars will most likely be able to compete with their competitors only with the advent of the second generation of cheaper and more reliable models, which are expected by 2020, and will appear on the roads with already more less developed network of refueling stations.

Despite the abundance of Japanese names among the manufacturers of hydrogen cars, they are interested in this type of transport on other continents. Among well-known manufacturers Hydrogen plans are in: General Electrics, Diamler, General Motors, Mercedes-Benz, Nissan, Volkswagen.

Results

As is often the case, the world is not black and white, and hydrogen will not be the only source of energy in the future. This element, together with other alternative energy sources, will be part of the solution to the problem of environmental pollution and the disappearance of natural resources. The prospect of this type of fuel and hydrogen cars will begin to clear up in 2015 with the appearance of the first mass-produced cars on the roads. How much they can compete with electric vehicles, we will most likely find out in 2020 as further development technologies and the emergence of the second generation of fuel cars.

We live in the 21st century, the time has come to create the fuel of the future, which will replace traditional fuel and eliminate our dependence on it. Fossil fuels are our main source of energy today.

Over the past 150 years, the amount of carbon dioxide in the atmosphere has increased by 25%. Burning hydrocarbons results in pollution such as smog, acid rain and air pollution.

What will be the fuel of the future?

Hydrogen is an alternative fuel of the future

Hydrogen is a colorless, odorless gas that makes up 75% of the mass of the entire universe. Hydrogen on Earth exists only in combination with other elements such as oxygen, carbon and nitrogen.

To use pure hydrogen, it must be separated from these other elements in order to be used as a fuel.

Transition to hydrogen of all cars and all petrol stations not an easy task, but in the long run, switching to hydrogen as an alternative fuel for cars will be very beneficial.

Turning water into fuel

Water fuel technologies use water, salt and a very inexpensive metal alloy. The gas that results from this process is pure hydrogen, which burns as a fuel without the need for external oxygen - and does not emit any pollution.

Sea water can be used directly as the main fuel, thus eliminating the need to add salt.

There is another way to turn water into fuel. It's called electrolysis. This is Brown's method of converting water into gas, which is also an excellent fuel for today's gasoline engines.

Why is Brown's gas a better fuel than pure hydrogen?

Let's take a look at all three types of hydrogen fuel solution - fuel cells, pure hydrogen, and Brown's gas - and see how they perform in relation to oxygen and its consumption:

Fuel cells: This method uses oxygen from the atmosphere while completely burning hydrogen in fuel cells. What comes out of exhaust pipe? Oxygen and water vapor! But oxygen originally came from the atmosphere, not from the fuel.

And so the use of fuel cells does not solve the problem: the environment is experiencing huge problems at the moment with the oxygen content in the air; we lose oxygen.

Hydrogen: This fuel is perfect, if not for one "but". The storage and distribution of hydrogen requires special equipment, and the fuel tanks of vehicles must withstand the high pressure of liquefied hydrogen gas.

Brown gas: It is the most advanced fuel for the operation of all our vehicles. Pure hydrogen comes directly from the water, that is, a hydrogen-oxygen pair, but, in addition, it burns in an internal combustion engine, releasing oxygen into the atmosphere: oxygen and water vapor enter the atmosphere from the exhaust pipe.

So, by burning Brown's gas as a fuel, it is possible to increase the oxygen in the air and thereby increase the oxygen content in our atmosphere. This contributes to the solution of a very dangerous environmental problem.

Brown's gas is the ideal fuel of the future

About using water as an alternative fuel for cars, about plans to convert gasoline engines to run on ordinary tap water, this postulate is a world revolution in the minds of people.

Now it's only a matter of time before everyone realizes that water is the best fuel for our vehicles. The person or persons who gave us this knowledge, we must remember them as heroes.

They were killed, their patents bought up by private individuals to keep their inventions out of the public eye; information about cars on the water lived on the Internet for no more than 1-2 hours ...
But now something has changed, apparently, those in power have decided “Let the games begin”!

Cars run on water and we know it for sure. The operation of gasoline engines on water is like a springboard for much the best technologies than those that already exist and that will quickly replace the idea of ​​driving cars on water.

But while oil companies stifle the idea of ​​a car on water, mastering higher technologies will not work, and the use of oil will continue. This is the general opinion of scientists, so they say all over the world.

Can the use of water as fuel change the life of the Earth?

Did you know that the Earth's water supply is not static? The amount of water on Earth is increasing every day.

It has been discovered that in the past few years, a large amount of water has been arriving daily from space in the form of water asteroids!

These huge asteroids are megatons of water that, once in the upper atmosphere, immediately evaporate, and eventually settle to Earth.

You can view NASA photos of these asteroids in Dr. Emoto's first book, The Water Message «. Why these water asteroids approach Earth and not other planets like Mars remains a mystery.

And is it really that this is happening only now or has it been happening throughout the history of the Earth. Another thing is that no one knows the answer.

Melting glaciers. In addition, the sea level is rising due to the melting of glaciers. As a consequence of climate warming, there is beginning to be too much water on Earth.

I've talked to scientists who think it would really help if a small amount of water could be used in some way during this time - for example, to run machines.

Running cars on water will help replenish the oxygen in our atmosphere: the main reason for switching to water as a fuel is our current environmental problems.

They are so big that if we do not do something to reduce the use of fossil fuels, our Earth will be destroyed. And it will no longer matter if the planet has water or not.

Sometimes a person consumes something that is potentially dangerous in order to become healthy. Running cars on water is akin to this concept. This could be potentially dangerous if we continued to use water as a fuel for an excessive period of time.

But all things considered, this solution is the best that governments can afford for the time being.

Even governments are gearing up to launch fuel cell vehicles powered by hydrogen. And to implement this technology, we will not have to change our engines - an alternative source of our fuel may not be the only one.

It is known that in the 30s of the last century in the Soviet Union at the Moscow Higher Technical School named after N.E. Bauman Soroko-Novitsky V.I., (head of the department "Light engines" until 1937) together with A.K. effect of hydrogen additives to gasoline on the ZIS-5 engine. There are also works on the use as hydrogen fuel which were carried out in our country by F. B. Perelman. However, the practical use of hydrogen as a motor fuel began in 1941. During the Great Patriotic War in besieged Leningrad, lieutenant technician B. I. Shelishch suggested use hydrogen, "worked out" in balloons, How motor fuel for GAZ-AA car engines.

Figure 1. Air defense post of the Leningrad Front of the Second World War, equipped with a hydrogen plant

On fig. 1 in the background is a hydrogen balloon lowered to the ground, from which hydrogen is pumped into a gas holder located in the foreground. From the gas tank with "spent" hydrogen, gaseous fuel is fed through a flexible hose to the internal combustion engine of the GAZ-AA car. Barrage balloons rose to a height of up to five kilometers and were a reliable anti-aircraft defense of the city, preventing enemy aircraft from carrying out targeted bombing. To lower balloons that have partially lost their lift, it was required great effort. This operation was carried out using a mechanical winch installed on a GAZ-AA vehicle. The ICE rotated the winch to lower the balloons. In the conditions of an acute shortage of gasoline, several hundred air defense posts were converted to run on hydrogen, which used GAZ-AA vehicles running on hydrogen.

After the war in the seventies of the last century, Bris Isaakovich was repeatedly invited to various scientific conferences, where in his speeches he spoke in detail about those distant heroic days. One of these events - the 1st All-Union School of Young Scientists and Specialists on Problems of Hydrogen Energy and Technology, organized on the initiative of the Central Committee of the All-Union Leninist Young Communist League, the Commission of the USSR Academy of Sciences on Hydrogen Energy, the Institute of Atomic Energy named after I.V. Kurchatov and the Donetsk Polytechnic Institute, was held in September 1979 six months before his death. Boris Issakovich made his report "Hydrogen instead of gasoline" at the section "Technology of the use of Hydrogen" on September 9th.

In the 1970s, several research organizations in the USSR intensively carried out work on the use of hydrogen as a fuel. The most famous organizations are the Central Research Automobile and Automotive Institute (NAMI), the Institute of Mechanical Engineering Problems of the Academy of Sciences of the Ukrainian SSR (IPMASH AS of the Ukrainian SSR), the Sector of Mechanics of Inhomogeneous Media of the Academy of Sciences of the USSR (SMNS of the Academy of Sciences of the USSR), the Plant-VTUZ at ZIL, etc. In particular , in NAMI, under the leadership of E. V. Shatrov, since 1976, research and development work has been carried out to create a hydrogen minibus RAF 22034. An engine power system has been developed that allows it to work on hydrogen. It has passed a full range of bench and laboratory road tests.

Figure 2. From left to right Shatrov E. V., Kuznetsov V. M., Ramensky A. Yu.

On fig. 2 photographs from left to right: Shatrov E.V - scientific supervisor of the project; Kuznetsov V. M. - head of the group of hydrogen engines; Ramensky A.Yu. - NAMI postgraduate student, who made a significant contribution to the organization and conduct of R&D to create a hydrogen car. Photos of stands for testing a hydrogen-powered engine and a RAF 22034 minibus running on hydrogen and gasoline-hydrogen fuel compositions (BVTK) are shown in fig. 3 and 4.

Figure 3 Engine compartment Bolks No. 20 for testing internal combustion engines on hydrogen of the Department of Motor Laboratories of NAMI

Figure 4. Hydrogen minibus RAF (NAMI)

The first prototype minibus was built at NAMI in the period 1976-1979 (Fig. 4). Since 1979, NAMI carried out its laboratory road tests and trial operation.

At the same time, work on the creation of vehicles powered by hydrogen was carried out at the IPMASH Academy of Sciences of the Ukrainian SSR and the SMNS of the Academy of Sciences of the USSR and the Vtuze Plant at ZIL. Thanks to active position academician Struminsky V.V. (Fig. 5), head of the SMNS of the USSR Academy of Sciences, several samples of minibuses were used at the XXII Olympic Summer Games in Moscow in 1980.

Figure 5. From left to right Legasov V. A., Semenenko K. N. Struminsky V. V.

As the head institute of the Ministry automotive industry USSR NAMI cooperated with the organizations mentioned above. An example of such cooperation was joint research with IPMash of the Academy of Sciences of the Ukrainian SSR, whose director at that time was A.N. Podgorny, Corresponding Member of the Academy of Sciences of the Ukrainian SSR. A. I., Solovya V. V. and many others (Fig. 6).

Figure 6. Employees of the IPMASH Academy of Sciences of the Ukrainian SSR, from left to right Podgorny A. N., Varshavsky I. L., Mishchenko A. I.

The developments of this institute are widely known for the creation of cars and forklifts operating at the BVTK with metal hydride hydrogen storage systems on board.

Another example of cooperation between NAMI and the leading research institutes of the country was the work on the creation of metal hydride hydrogen storage systems in a car. Within the framework of the consortium on the creation of metal hydride storage systems, three leading organizations collaborated: IAE named after I. V. Kurchatov, NAMI and Moscow State University named after M. V. Lomonosov. The initiative to create such a consortium belonged to Academician V. A. Legasov. The I. V. Kurchatov Institute of Atomic Energy was the lead developer of a metal hydride hydrogen storage system on board a car. The project manager was Yu. F. Chernilin, and A. N. Udovenko and A. Ya. Stolyarevsky were active participants in the work.

Metal hydride compounds were developed and manufactured in the required quantity by Moscow State University. M. V. Lomonosov. This work was carried out under the guidance of K. N. Semenenko, Head of the Department of Chemistry and High Pressure Physics. On November 21, 1979, applications No. 263140 and 263141 were registered in the State Register of Inventions of the USSR with the priority of the invention on June 22, 1978. Author's certificates for hydrogen storage alloys A. S. No. 722018 and No. 722021 dated November 21, 1979 were among the first inventions in this area in the USSR and in the world.

The inventions proposed new compositions that make it possible to significantly increase the amount of stored hydrogen. This was achieved by modifying the composition and the amount of components in alloys based on titanium or vanadium. Such compositions made it possible to achieve a concentration of 2.5 to 4.0 mass percent of hydrogen. The release of hydrogen from the intermetallic compound was carried out in the temperature range of 250-400°C. This result is still practically the maximum achievement for alloys of this type. Scientists from leading scientific organizations of the USSR involved in the development of materials and devices based on hydrides of intermetallic alloys took part in the development of the alloys - Moscow State University. M. V. Lomonosov (Semenenko K. N., Verbetsky V. N., Mitrokhin S. V., Zontov V. S.); NAMI (Shatrov E.V., Ramensky A.Yu.); IMash of the Academy of Sciences of the USSR (Varshavsky I. L.); Plant-VTUZ at ZIL (Gusarov V.V., Kabalkin V.N.). In the mid-eighties, tests of a metal hydride hydrogen storage system on board a RAF 22034 minibus operating at the BVTK were carried out at the Department of Engines Running on Gas and Other Alternative Fuels of NAMI (Head of the Department Ramensky A. Yu.) . The following employees of the department took an active part in the work: V. M. Kuznetsov, N. I. Golubchenko, A. I. Ivanov, Yu. A. Kozlov. 7.

Figure 7. Hydrogen automotive hydrogen metal hydride battery (1983)

In the early eighties, a new direction in the use of hydrogen as a fuel for cars began to emerge, which is currently regarded as the main trend. This direction is associated with the creation of fuel cell vehicles. The creation of such a car was carried out in NPP "Kvant". Under the direction of N. S. Lidorenko. The car was first presented on international exhibition"Electro-82" in 1982 in Moscow (Fig. 8).

Figure 8. RAF hydrogen minibus powered by fuel cells (NPP KVANT)

In 1982, the RAF minibus, on board of which electrochemical generators were mounted and an electric drive was installed, was demonstrated to the Deputy Minister of the Automotive Industry, E. A. Bashindzhagyan. N.S. Lidorenko himself demonstrated the car. For the prototype, the fuel cell vehicle had good driving characteristics, which was noted by all the participants of the viewing with some satisfaction. It was planned to carry out this work together with the enterprises of the USSR Ministry of Automotive Industry. However, in 1984, N. S. Lidorenko left the post of head of the enterprise; this may be due to the fact that this work was not continued. The creation of the first Russian hydrogen fuel cell car, built by the company's staff for more than 25 years, could claim to be a historical event in our country.

Features of internal combustion engines when operating on hydrogen

In relation to gasoline, hydrogen has a 3 times higher calorific value, 13-14 times lower ignition energy, and, which is essential for internal combustion engines, wider ignition limits fuel-air mixture. These properties of hydrogen make it extremely effective for use in internal combustion engines, even as an additive. At the same time, the disadvantages of hydrogen as a fuel include: a drop in ICE power compared to gasoline analogue; "hard" process of combustion of hydrogen-air mixtures in the region of stoichiometric composition, which leads to detonation at high loads. This feature of hydrogen fuel requires changes in the design of the internal combustion engine. For existing engines, it is necessary to use hydrogen in combination with hydrocarbon fuels, such as gasoline. or natural gas.

For example, the organization of the fuel supply of hydrogen-gasoline fuel compositions (BVTK) for existing vehicles must be carried out in such a way that idle move and partial loads, the engine ran on fuel compositions with a high hydrogen content. As loads increase, the hydrogen concentration should decrease and the hydrogen supply should be stopped at full throttle. This will keep the power characteristics of the engine at the same level. On fig. 9 shows graphs of changes in the economic and toxic characteristics of an engine with a working volume of 2.45 liters. and a compression ratio of 8.2 units. on the composition of the benzohydrogen-air mixture and the concentration of hydrogen in the BVTK.

Figure 9. Economic and toxic characteristics of ICE on hydrogen and BVTK

Adjusting characteristics of the engine according to the composition of the mixture at a constant power Ne=6.2 kW and rotational speed crankshaft n=2400 rpm make it possible to imagine how the engine performance changes when operating on hydrogen, BVTK and gasoline.

The power and speed indicators of the engine for testing were chosen in such a way that they most fully reflect the operating conditions of the car in urban conditions. Engine power Ne=6.2 kW and crankshaft speed n=2400 rpm constant speed 50-60 km/h horizontally, flat road. As can be seen from the graphs, as the hydrogen concentration in the BVTK increases, the effective Engine efficiency increases. The maximum efficiency value at a power of 6.2 kW and a crankshaft speed of 2400 rpm reaches 18.5 percent on hydrogen. This is 1.32 times higher than when the engine is running at the same load on gasoline. The maximum value of the effective efficiency of the engine on gasoline is 14 percent at this load. In this case, the composition of the mixture corresponding to the maximum efficiency of the engine (effective lean limit) is shifted towards lean mixtures. So, when working on gasoline, the effective limit of depletion of the fuel-air mixture corresponded to an excess air coefficient (a) equal to 1.1 units. When operating on hydrogen, the excess air coefficient corresponding to the effective limit of depletion of the fuel-air mixture a=2.5. An equally important performance indicator car engine internal combustion at partial loads is the toxicity of exhaust gases (EG). The study of the control characteristics of the engine in terms of the composition of the mixture on the BVTK with various concentrations of hydrogen showed that as the mixture became leaner, the concentration of carbon monoxide (CO) in the exhaust gases decreased almost to zero, regardless of the type of fuel. An increase in the concentration of hydrogen in the BVTK leads to a decrease in the emission of CnHm hydrocarbons with exhaust gases. When operating on hydrogen, the concentration of this component dropped to zero in certain modes. When operating on this type of fuel, the emission of hydrocarbons was largely determined by the intensity of combustion in the chamber combustion engine. The formation of nitrogen oxides NxOy, as is known, is not related to the type of fuel. Their concentration in the exhaust gas is determined temperature regime combustion of the fuel-air mixture. The ability of the engine to operate on hydrogen and BVTK in the range of lean mixtures makes it possible to reduce the maximum cycle temperature in the combustion chamber of the internal combustion engine. This significantly reduces the concentration of nitrogen oxides. When the fuel-air mixture is depleted above a=2, the concentration of NxOy decreases to zero. In 2005, the NAVE developed the GAZEL minibus, which operates at the BVTK. In December 2005, he was presented at one of the events held at the Presidium of the Russian Academy of Sciences. The presentation of the minibus was dedicated to the 60th anniversary of the NAVE President P. B. Shelishch. A photo of a hydrogen-fueled minibus is shown in Fig.10.

Figure 10. Hydrogen minibus "Gazelle" (2005)

From August 20 to 25, 2006, from August 20 to August 25, 2006, the NAVE held a hydrogen car rally to assess the reliability of hydrogen-fueled equipment and promote the prospects for a hydrogen economy, primarily in the field of road transport. The run was carried out along the route Moscow - Nizhny Novgorod - Kazan - Nizhnekamsk - Cheboksary - Moscow with a length of 2300 km. The rally was timed to coincide with the First World Congress "Alternative Energy and Ecology". Two hydrogen cars took part in the run. The second truck of the GAZ 3302 multi-fuel vehicle ran on hydrogen, compressed natural gas, BVTK and gasoline. The car was equipped with 4 lightweight fiberglass cylinders with a working pressure of 20 MPa. The mass of the onboard hydrogen storage system is 350 kg. The driving range of the car on the BVTK was 300 km.

Supported by federal agency for Science and Innovation NAVE with the active participation of the Moscow Power Engineering Institute MPEI (TU), Avtokombinat No. 41, the Engineering and Technical Center "Hydrogen Technologies" and Slavgaz LLC, a prototype of the GAZ 330232 "GAZEL-FERMER" vehicle with a payload capacity of 1.5 tons was created, working on BVTK with an electronic system for supplying hydrogen and gasoline. The vehicle is equipped with a three-way exhaust gas converter. On fig. 11 shows photographs of the car and a set of electronic equipment for supplying hydrogen to the internal combustion engine.

Figure 11. Prototype car GAZ 330232 "GAZEL-FARMER"

Prospects for the introduction of hydrogen in road transport

The most promising direction in the field of using hydrogen for automotive technology are combined power plants based on electrochemical generators with fuel cells (FC) . At the same time, a necessary condition is the production of hydrogen from renewable, environmentally friendly energy sources, for the production of which, in turn, environmentally friendly materials and technologies should be used.

Unfortunately, in the short term, the use of such high-tech vehicles on a large scale is problematic. This is due to the imperfection of a number of technologies used in their production, the insufficient development of the design of electrochemical generators, and the limited and high cost of the materials used. For example, the specific cost of one kW of ECG power on fuel cells reaches 150-300 thousand rubles (at the exchange rate of the Russian ruble is 30 rubles/USD). Another important element of restraining the promotion of hydrogen technology with fuel cells in the automotive market is the insufficient development of the design of such vehicles as a whole. In particular, there are no reliable data when testing a car for fuel efficiency in real operation. As a rule, the evaluation of the efficiency of the power plant of the installation is carried out on the basis of the current-voltage characteristic. Such an assessment of efficiency does not correspond to the assessment of the effective efficiency of the internal combustion engine, which is accepted in the practice of engine building, the calculation of which also takes into account all mechanical losses associated with the drive of engine units. There are no reliable data on the fuel efficiency of vehicles in real operating conditions, the value of which is affected by the need to maintain additional on-board devices and systems installed on vehicles, both traditionally and related to the design features of fuel cell vehicles. There are no reliable data on the evaluation of efficiency in conditions of negative temperatures, at which it is necessary to maintain a temperature regime that ensures the operability of both the power plant itself and the supplied fuel, and heating the driver's cabin or passenger compartment. For modern cars, the operating mode can reach -40 ° C, this should be especially taken into account in Russian conditions operation.

As is known, in fuel cells, water is not only a product of the reaction of the interaction of hydrogen and oxygen, but also actively participates in the working process of energy generation, wetting the solid polymer materials that are part of the design of fuel cells. In modern technical literature, there are no data on the reliability and durability of fuel cells at low temperatures. Very conflicting data are also published in the literature on the durability of ECH operation on fuel cells.

In this regard, it is quite natural that a number of the world's leading automakers promote hydrogen-powered vehicles equipped with internal combustion engines. First of all, these are such well-known companies as BMW and Mazda. BMW Hydrogen-7 and Mazda 5 Hydrogen RE Hybrid (2008) engines have been successfully converted to hydrogen.

From the point of view of design reliability, the relative low cost per kW of installed capacity of power plants based on internal combustion engines running on hydrogen is significantly superior to ECG on fuel cells, however, internal combustion engines have, as is commonly believed, lower efficiency. In addition, the exhaust gases of an internal combustion engine may contain some toxic substances. The use of combined (hybrid) power plants should be considered as the main direction for improving automotive equipment equipped with an internal combustion engine in the short term. The best result in terms of fuel efficiency and exhaust gas toxicity should apparently be expected from the use of hybrid installations with a sequential scheme for converting the chemical energy of the fuel in the internal combustion engine into the mechanical energy of the vehicle. With a serial scheme ICE car operates almost continuously with maximum fuel efficiency, driving an electric generator that supplies electric current to the electric motor of the vehicle's wheel drive and the energy storage device (battery). The main optimization task for such a scheme is to find a compromise between the fuel efficiency of the internal combustion engine and the toxicity of its exhaust gases. The peculiarity of the solution of the problem lies in the fact that the maximum efficiency of the engine is achieved when operating at lean air-fuel mixture, and the maximum reduction in exhaust gas toxicity is achieved with a stoichiometric composition, in which the amount of fuel supplied to the combustion chamber is supplied strictly in accordance with the amount of air required for its complete combustion. The formation of nitrogen oxides is limited by the lack of free oxygen in the combustion chamber, and the incompleteness of fuel combustion by the exhaust gas converter. In modern internal combustion engines, a sensor for measuring the concentration of free oxygen in the exhaust gas of an internal combustion engine sends a signal to electronic system fuel supply, which is designed in such a way as to maintain the maximum stoichiometric composition of the air-fuel mixture in the engine combustion chamber in all ICE modes. For hybrid power plants with a sequential scheme, it is possible to achieve the best efficiency of air-fuel mixture control due to the absence of alternating loads on the internal combustion engine. At the same time, from the point of view of fuel efficiency, the ICE stoichiometric composition of the air-fuel mixture is not optimal. The maximum efficiency of the engine always corresponds to a mixture lean by 10-15 percent compared to the stoichiometric one. In this case, the efficiency of the internal combustion engine when operating on a lean mixture can be 10-15 higher than when operating on a mixture of a stoichiometric composition. The solution to the problem of increased emission of harmful substances, which is typical for spark-ignition internal combustion engines in these modes, is possible as a result of switching the operation of the internal combustion engine to hydrogen, methane-hydrogen fuel compositions (BVTK) or methane-hydrogen fuel compositions (MVTK). The use of hydrogen as a fuel or as an additive to the main fuel can significantly expand the limits of effective depletion of the air-fuel mixture. This circumstance allows you to significantly increase the efficiency of the internal combustion engine and reduce the toxicity of exhaust gases.

The exhaust gases of internal combustion engines contain over 200 different hydrocarbons. Theoretically, in the case of combustion of homogeneous mixtures (from equilibrium conditions), hydrocarbons should not be contained in the exhaust gases of the internal combustion engine, however, due to the inhomogeneity of the air-fuel mixture in the combustion chamber of the internal combustion engine, different initial conditions for the fuel oxidation reaction occur. The temperature in the combustion chamber varies in its volume, which also significantly affects the completeness of combustion of the air-fuel mixture. In a number of studies, it was found that near the relatively cold walls of the combustion chamber, the flame is extinguished. This leads to a deterioration in the conditions for the combustion of the air-fuel mixture in the near-wall layer. Daneshyar H and Watf M photographed the process of combustion of a gasoline-air mixture in the immediate vicinity of the engine cylinder wall. Photographing was carried out through a quartz window in the cylinder head of the engine. This made it possible to determine the thickness of the quenching zone in the range of 0.05-0.38 mm. In the immediate vicinity of the walls of the combustion chamber CH increases by 2-3 times. The authors conclude that the quench zone is one of the sources of hydrocarbon release.

Another important source of hydrocarbon formation is engine oil, which enters the engine cylinder as a result of inefficient removal from the walls. oil scraper rings or through the gaps between the valve stems and their guide bushings. Studies show that oil consumption through the gaps between the valve stems and their guide bushings in automotive gasoline ICEs reaches 75% of the total oil consumption for waste.

At operation of the internal combustion engine on hydrogen, the fuel does not contain carbonaceous substances. In this regard, the vast majority of publications contain information that the exhaust gases of internal combustion engines cannot contain hydrocarbons. However, this turned out not to be the case. Undoubtedly, with an increase in the hydrogen concentration in the BVTK and MVTK, the concentration of hydrocarbons decreases significantly, but does not disappear completely. To a large extent this may be due to the imperfection of the design. fuel equipment, dosing the supply of hydrocarbon fuel. Even a small leak of hydrocarbons during the operation of the internal combustion engine on ultra-lean mixtures can lead to the release of hydrocarbons. Such an emission of hydrocarbons can be associated with wear of the cylinder-piston group and, as a result, increased oil waste, etc. In this regard, when organizing the combustion process, it is necessary to maintain the combustion temperature at a level at which the combustion of hydrocarbon compounds is sufficiently complete.

In the process of fuel combustion, nitrogen oxides are formed behind the flame front in the zone of elevated temperature caused by the fuel combustion reaction. The formation of nitrogen oxides, if these are not nitrogen-containing compounds, are formed as a result of the interaction of oxygen and nitrogen in the air. The generally accepted theory of the formation of nitrogen oxides is the thermal theory. In accordance with this theory, the yield of nitrogen oxides is determined by the maximum temperature of the cycle, the concentration of nitrogen and oxygen in the combustion products and does not depend on the chemical nature of the fuel of the fuel type (in the absence of nitrogen in the fuel). In the exhaust gases of internal combustion engines with spark ignition, the content of nitrogen oxide is 99% of the amount of all nitrogen oxides (NOx). After leaving the atmosphere, NO is oxidized to NO2.

When an internal combustion engine runs on hydrogen, the formation of nitrogen oxide has some features compared to the operation of an engine on gasoline. This is due to the physicochemical properties of hydrogen. The main factors in this case are the temperature of combustion of hydrogen-air and its ignition limits. As is known, the ignition limits of a hydrogen-air mixture are in the range of 75% - 4.1%, which corresponds to an excess air coefficient of 0.14 - 9.85, while for isooctane it is in the range of 6.0% -1.18%, which corresponds to coefficient, excess air 0.29 - 1.18. An important feature combustion of hydrogen is the increased rate of combustion of stoichiometric mixtures. On fig. 12 shows a graph of dependencies characterizing the course of working processes of an internal combustion engine when operating on hydrogen and gasoline.

Figure 12. Changing the parameters of the working process of the internal combustion engine when running on hydrogen and gasoline, internal combustion engine power 6.2 kW, crankshaft speed 2400 rpm.

As follows from their graphs, the transfer of internal combustion engines from gasoline to hydrogen leads in the region of stoichiometric mixtures to a sharp increase in the maximum cycle temperature. The graph shows that the rate of heat release during the operation of the internal combustion engine on hydrogen in top dead ICE point is 3-4 times higher than when running on gasoline. At the same time, traces of pressure fluctuations are clearly visible on the indicator diagram, the appearance of which at the end of the compression stroke is characteristic of “hard” combustion of the air-fuel mixture. Figure 13 shows indicator diagrams describing the change in pressure in the internal combustion engine cylinder (ZMZ-24D, Vh = 2.4 liters, compression ratio -8.2). depending on the angle of rotation of the crankshaft (power 6.2 kW, h.v. to 2400 rpm) when operating on gasoline and hydrogen.

Figure 13. Indicator ICE diagrams(ZMZ-24-D, Vh = 24 l., compression ratio 8.2) with a power of 6.2 kW and h.p. to 2400 rpm. when running on gasoline and hydrogen

When the internal combustion engine is running on gasoline, the uneven flow is clearly visible indicator charts from cycle to cycle. When working on hydrogen, especially with a stoichiometric composition, there is no unevenness. At the same time, the ignition advance angle was so small that it can practically be considered equal to zero. Noteworthy is a very sharp increase in pressure after TDC, indicating an increased rigidity of the process. The lower graph shows the indicator diagrams when running on hydrogen at an excess air ratio of 1.27. The ignition timing was 10 degrees c.c. On some indicator diagrams, traces of the "hard" operation of the internal combustion engine are clearly visible. This nature of the flow of the working process of the internal combustion engine when using hydrogen as a fuel contributes to an increased formation of nitrogen oxides. The maximum value of the concentration of nitrogen oxides in the exhaust gas corresponds to the operation of the internal combustion engine with an excess air coefficient of 1.27. This is quite natural, since the air-fuel mixture contains a large amount of free oxygen and, as a result of high combustion rates, a high combustion temperature of the air-fuel charge takes place. However, when switching to leaner mixtures, the heat release rates decrease. The maximum cycle temperature is also reduced, and hence the concentration of nitrogen oxides in the exhaust gas.

Figure 14. Adjustment characteristics for the composition of the mixture during the operation of the internal combustion engine on gasoline-hydrogen fuel compositions, the power of the internal combustion engine is 6.2 kW, the crankshaft speed is 2400 rpm. 1. Gasoline, 2. Gasoline +H2 (20%), 3. Gasoline +H2 (50%), 4. Hydrogen

On fig. 14 shows the dependences of changes in the emission of toxic substances from the ICE exhaust gas when operating on gasoline, hydrogen-fuel compositions and hydrogen. As follows from the graph, the highest value of NOx emissions corresponds to the operation of internal combustion engines on hydrogen. At the same time, as the air-fuel mixture becomes leaner, the NOx concentration decreases, reaching almost zero value at an excess air ratio of more than 2 units. Thus, the conversion of an automobile engine to hydrogen makes it possible to radically solve the problem of fuel efficiency, exhaust gas toxicity and reduction of carbon dioxide emissions.

The use of hydrogen as an additive to the main fuel can contribute to solving the problem of improving the fuel efficiency of internal combustion engines, reducing the emission of toxic substances and reducing the emission of carbon dioxide, the requirements for the content of which in the exhaust gas of internal combustion engines are constantly tightening. The addition of hydrogen by weight in the range of 10-20 percent may become optimal for cars with hybrid engines in the very near future.

The use of hydrogen as a motor fuel can be effective only when creating specialized designs. Currently, leading manufacturers of automotive engines are working on the creation of such motors. In principle, the main directions in which it is necessary to move when creating a new design of hydrogen internal combustion engines are known. These include:

1. The use of internal mixture formation will improve the specific weight and size parameters of a hydrogen engine by 20-30 percent.

2. The use of ultra-lean hydrogen-air mixtures for hybrid power plants will make it possible to significantly reduce the combustion temperature in the combustion chamber of the internal combustion engine and create prerequisites for increasing the degree of compression of the internal combustion engine, the use of new materials, including for the inner surface of the combustion chamber, which will reduce heat loss to the cooling system engine.

All this, according to experts, will make it possible to bring the effective efficiency of an internal combustion engine running on hydrogen to 42-45 percent, which is quite comparable with the efficiency of electrochemical generators, for which there is currently no data on economic efficiency in the conditions of actual operation of vehicles, taking into account the drive of auxiliary units, heating salon, etc.

History of the hydrogen engine. If oil is called fuel today(the fuel of the century), then hydrogen can be called the fuel of the future.

Under normal conditions, hydrogen is a colorless, odorless and tasteless gas, the lightest substance (14.4 times lighter than air); it has very low boiling and melting points, respectively, -252.6 and -259.1 CC.

Liquid hydrogen is a colorless liquid, odorless, at -253 ° C it has a mass of 0.0708 g / cm 3.

Hydrogen owes its name to the French scientist Antoine Laurent Lavoisier, who in 1787, decomposing and re-synthesizing water, proposed to name the second component (oxygen was known) - hydrophene, which means “giving birth to water”, or “hydrogen”. Prior to this, the gas released during the interaction of acids with metals was called "combustible air".

The first patent for an engine running on a mixture of hydrogen and oxygen appeared in 1841 in England, and 11 years later, the court watchmaker Christian Teiman built an engine in Munich that worked on a mixture of hydrogen and air for several years.

One of the reasons that these engines did not gain popularity was the lack of free hydrogen in nature.

The hydrogen engine was again turned to in our century - in the 70s in England, scientists Ricardo and Brustal conducted serious research. Experimentally - by changing only the supply of hydrogen - they found that a hydrogen engine can operate over the entire load range, from idle to full load. Moreover, on poor mixtures, higher values ​​of the indicator efficiency were obtained than on gasoline.

In Germany in 1928, the Zeppelin airship company used hydrogen as a fuel enricher to make a long-range test flight across the Mediterranean.

Before the Second World War, in the same Germany, railcars powered by hydrogen were used. Hydrogen for them was obtained in high-pressure electrolyzers operated from the mains at gas stations located near the railway.

The work of Rudolf Erren played an important role in the improvement of the hydrogen engine. He was the first to use internal mixture formation, which made it possible to convert liquid fuel engines to hydrogen while maintaining the main fuel system and thereby ensure the operation of the engine on hydrocarbon fuel, hydrogen and liquid fuel with a hydrogen additive. It is interesting to note that it was possible to switch from one type of fuel to another without stopping the engine.

One of the engines converted by Erren is the Leyland diesel bus, the trial operation of which showed high efficiency when hydrogen was added to diesel fuel.

Erren also developed a hydrogen-oxygen engine, the combustion product of which was water vapor. Some of the steam returned to the cylinder along with oxygen, and the rest condensed. The ability to operate such an engine without external exhaust was used on pre-war German submarines. In the surface position, the diesel engines ensured the progress of the boat and provided energy for the decomposition of water into hydrogen and oxygen; in the submerged position, they worked on a steam-oxygen mixture and hydrogen. At the same time, the submarine did not need air for diesel engines and did not leave traces on the surface of the water in the form of bubbles of nitrogen, oxygen and other combustion products.

In our country, research into the possibilities of using hydrogen in internal combustion engines began in the 1930s.

During the blockade of Leningrad, for lifting and lowering air barrage balloons, winches with GAZ-AA engines were used, which were switched to hydrogen power. Since 1942, hydrogen has been successfully used in the Moscow air defense service, they inflated balloons.

In the 1950s, it was proposed to use hydrogen on river ships, obtained by the decomposition of water by the current of hydroelectric power plants.

Current use of hydrogen

In the 1970s, under the guidance of Academician V.V. Struminsky, tests were carried out on the GAZ-652 automobile engine running on gasoline and hydrogen, and the GAZ-24 engine running on liquid hydrogen. Tests have shown that when running on hydrogen, efficiency increases and engine heating decreases.

At the Kharkov Institute of Mechanical Engineering Problems of the Academy of Sciences of the Ukrainian SSR and the Kharkov Automobile and Road Institute, under the guidance of Professor I. L. Varshavsky, studies were carried out on the detonation resistance of hydrogen-air and gasoline-hydrogen-air mixtures, as well as developments were made on converting to hydrogen and adding hydrogen to gasoline of Moskvich-412 car engines, "VAZ-2101", "GAZ-24" with the use of energy storage substances and heavy metal hydrides for the production and storage of hydrogen. These developments have reached the stage of trial operation on buses and taxis.

Appeared in astronautics new class aircraft with hypersonic speeds in the earth's atmosphere. To achieve such speeds, a fuel with a high calorific value and a low molecular weight of combustion products is required; in addition, it must have a large cooling capacity.

Hydrogen meets these requirements perfectly. It is able to absorb heat 30 times more than kerosene. When heated from -253 to +900 °C (temperature at the engine inlet), 1 kg of hydrogen can absorb more than 4000 kcal.

Washing the lining from the inside aircraft before entering, into the combustion chamber, liquid hydrogen absorbs all the heat released during the acceleration of the apparatus to a speed 10-12 times greater than the speed of sound in air.

Liquid hydrogen paired with liquid oxygen was used in last steps superheavy American launch vehicles "Saturn-5", which to a certain extent contributed to the success of the space programs "Apollo" and "Skylab".

Motor properties of fuel

Basic physicochemical and motor properties hydrogen in comparison with propane and gasoline are given in table. 1.

Hydrogen has the highest energy and mass indicators, exceeding traditional hydrocarbon fuels by 2.5-3 times, and alcohols - by 5-6 times. However, due to its low density in terms of volumetric heat output, it is inferior to most liquid and gaseous fuels. The heat of combustion of 1 m 3 of a hydrogen-air mixture is 15% less than that of gasoline. Due to the worse cylinder filling due to low density, the liter power of gasoline engines decreases by 20-25% when converted to hydrogen.

The ignition temperature of hydrogen mixtures is higher than that of hydrocarbon mixtures, but the former require less energy to ignite. Hydrogen-air mixtures are different high speed combustion in the engine, and combustion proceeds at almost constant volume, which leads to a sharp increase in pressure (3 times higher than the gasoline equivalent). However, on lean and even very lean mixtures, the burning rate of hydrogen ensures the normal operation of the engine.

Hydrogen-air mixtures have an exceptionally wide combustibility range, which allows for any load changes to apply high-quality regulation. The low flammability limit ensures the operation of the hydrogen engine at all speed modes in a wide range of mixture composition, as a result of which its efficiency at partial loads increases by 25-50%.

The following methods are known for supplying hydrogen to internal combustion engines: injection into the intake manifold; by modifying the carburetor, similar to liquefied and natural gas supply systems; individual dosing of hydrogen approx. inlet valve; direct injection under high pressure into the combustion chamber.

To ensure stable operation of the engine, the first and second methods can only be used with partial exhaust gas recirculation, with the help of an additive to the fuel charge of water and gasoline additives.

The best results are obtained by direct injection of hydrogen into the combustion chamber, which completely eliminates backfires in intake tract, the maximum power not only does not decrease, but can be increased by 10-15%.

Fuel supply

Volumetric and mass characteristics of various hydrogen storage systems are given in Table. 2. All of them are inferior to gasoline in size and weight.

Due to the small energy reserve and a significant increase in size and weight fuel tank hydrogen gas is not used. Do not apply to vehicles and heavy high-pressure cylinders.

Liquid hydrogen in cryogenic tanks with double walls, the space between which is thermally insulated.

Of great practical interest is the accumulation of hydrogen using metal hydrides. Some metals and alloys, such as vanadium, niobium, iron-titanium (FeTi), manganese-nickel (Mg + 5% Ni) and others, can combine with hydrogen under certain conditions. In this case, hydrides containing a large amount of hydrogen are formed. If heat is applied to the hydride, it will decompose, releasing hydrogen. Recovered metals and alloys can be reused for hydrogen bonding.

Hydride systems typically use the heat from engine exhaust gases to release hydrogen. The hydride battery is charged with hydrogen under low pressure with simultaneous cooling with running water from the water supply. In terms of thermodynamic properties and low cost, FeTi alloy is the most suitable component.

A hydride battery is a pack of stainless steel tubes (hydride cartridges) filled with a powdered FeTi alloy and enclosed in a common shell. Exhaust gases of the engine or water are passed into the space between the tubes. The tubes are connected on one side by a collector, which serves to store a small supply of hydrogen necessary to start the engine and operate it in transient conditions. In terms of mass and volume, hydride batteries are comparable to liquid hydrogen storage systems. In terms of energy intensity, they are inferior to gasoline, but surpass lead-acid batteries.

The hydride storage method is in good agreement with the operating modes of the engine through automatic control of the exhaust gas flow through the hydride accumulator. The hydride system allows the most complete utilization of heat losses with exhaust gases and cooling water. An experimental hydride-cryogenic system was used on the Chevrolet Monte Carlo. In this system, the engine is started on liquid hydrogen, and the hydride accumulator is switched on after the engine warms up, and water from the cooling system is used to heat the hydride.

In pre-war Germany, in an experimental hydride system developed by Daimler-Benz, two hydride batteries were used, one of which - low-temperature - absorbs heat from the environment and works as an air conditioner, the other is heated by coolant from the engine cooling system. The time it takes to charge a hydride battery depends on the amount of time it takes to dissipate heat. When cooling tap water time full refueling hydride battery with a capacity of 65 liters, containing 200 kg of FeTi alloy and absorbing 50 m3 of hydrogen, is 45 minutes, and 75% filling occurs in the first 10 minutes.

Benefits of Hydrogen

The main advantages of hydrogen as a fuel at present are unlimited supplies raw materials and the absence or small amount of harmful substances in the exhaust gases.

The raw material base for hydrogen production is practically unlimited. Suffice it to say that it is the most abundant element in the universe. In the form of plasma, it makes up almost half the mass of the Sun and most stars. The gases of the interstellar medium and gaseous nebulae are also mainly composed of hydrogen.

In the earth's crust, the hydrogen content is 1% by mass, and in water - the most common substance on Earth - 11.19% by mass. However, free hydrogen is extremely rare and occurs in minimal amounts in volcanic and other natural gases.

Hydrogen is a unique fuel that is extracted from water and, after combustion, forms water again. If oxygen is used as an oxidizing agent, then the only product of combustion will be distilled water. When air is used, nitrogen oxides are added to water, the content of which depends on the excess air coefficient.

When using hydrogen, poisonous lead antiknock agents are not required.

Despite the absence of carbon in hydrogen fuel, the exhaust gases due to the burnout of hydrocarbon lubricants entering the combustion chamber may contain a small amount of carbon monoxide and hydrocarbons.

In 1972, General Motors (USA) held a car competition for the cleanest exhaust. The competition was attended by battery electric vehicles and 63 vehicles running on various fuels, including gas - ammonia, propane. The first place was awarded to a Volkswagen converted to hydrogen, whose exhaust gases turned out to be cleaner than the ambient atmospheric air consumed by the engine.

When internal combustion engines operate on hydrogen, due to the significantly lower emission of solid particles and the absence of organic acids formed during the combustion of hydrocarbon fuels, the service life of the engine is increased and repair costs are reduced.

About the disadvantages

Gaseous hydrogen has a high diffusivity - its diffusion coefficient in air is more than 3 times higher compared to oxygen, hydrogen dioxide and methane.

The ability of hydrogen to penetrate into the thickness of metals, called hydrogenation, increases with increasing pressure and temperature. The penetration of hydrogen into the crystal lattice of most metals by 4-6 mm during hardening is reduced by 1.5-2 mm. The hydrogenation of aluminum, which reaches 15–30 mm, can be reduced to 4–6 mm during cold hardening. The hydrogenation of most metals is almost completely eliminated by doping with chromium, molybdenum, and tungsten.

Carbon steels are not suitable for the manufacture of parts in contact with liquid hydrogen, as they become brittle at low temperatures. For these purposes, chromium-nickel steels Kh18N10T, OH18N12B, Kh14G14NZT, brass L-62, LS 69-1, LZh MTs 59-1-1 are used , tin-phosphorus BR OF10-1, berylium BRB2 and aluminum bronzes.

Cryogenic (for low-temperature substances) containers for storing liquid hydrogen are usually made of aluminum alloys AMts, AMg, AMg-5V, etc.

A mixture of gaseous hydrogen with oxygen over a wide range is characterized by a tendency to flammability and explosiveness. Therefore, enclosed spaces should be equipped with detectors that control its concentration in the air.

The high ignition temperature and the ability to quickly dissipate in air make hydrogen in open volumes approximately equivalent in safety to natural gas.

To determine explosion safety in a traffic accident, liquid hydrogen from a cryogenic tank was spilled onto the ground, but it instantly evaporated and did not ignite when trying to set it on fire.

In the United States, a Cadillac Eldorado converted to hydrogen fuel was subjected to the following tests. A fully charged hydride tank with hydrogen was fired from a rifle with armor-piercing bullets. In this case, there was no explosion, and the gas tank exploded during a similar test.

Thus, the serious disadvantages of hydrogen - high diffusivity and a wide range of flammability and explosibility of a hydrogen-oxygen gas mixture are no longer reasons that prevent its use in transport.

prospects

As a fuel, hydrogen is already used in rocket technology. Currently, the possibilities of its application in aviation and on road transport. It is already known what the optimal hydrogen engine should be. It must have: a compression ratio of 10-12, a crankshaft speed of at least 3000 rpm internal system mixture formation and work at excess air coefficient α≥1.5. But for implementation. of such an engine, it is necessary to improve mixture formation in the engine cylinder and issue reliable design recommendations.

Scientists predict the beginning of the widespread use of hydrogen engines in cars not earlier than 2000. Until that time, it is possible to use hydrogen additives to gasoline; this will improve efficiency and reduce the amount of harmful emissions into the environment.

Of interest is the conversion to hydrogen rotary piston engine, since it does not have a crankcase and is therefore not explosive.

Currently, hydrogen is produced from natural gas. It is unprofitable to use such hydrogen as a fuel, it is cheaper to burn gas in engines. The production of hydrogen by decomposition of water is also economically unprofitable due to the high energy consumption for the splitting of a water molecule. However, research is being carried out in this direction. There are already experimental vehicles equipped with their own electrolysis plant, which can be connected to a common electrical network; the produced hydrogen is stored in a hydride accumulator.

To date, the cost of electrolytic hydrogen is 2.5 times higher than that obtained from natural gas. Scientists attribute this to the technical imperfection of electrolyzers and believe that their efficiency can be increased to 70-80% in the near future, in particular, through the use of high-temperature technology. By existing technology the final efficiency of electrolytic production of hydrogen does not exceed 30%.

Direct thermal decomposition of water requires a high temperature of about 5000 °C. Therefore, direct decomposition of water is not yet feasible even in a thermonuclear reactor - it is difficult to find materials capable of operating at such a temperature. The Japanese scientist T. Nakimura proposed a two-stage cycle of water decomposition for solar furnaces, which does not require such high temperatures. Perhaps the time will come when, in a two-stage cycle, hydrogen will be produced by helium-hydrogen stations located in the ocean, and nuclear-hydrogen stations, which produce more hydrogen than electricity.

Like natural gas, hydrogen can be transported through pipelines. Due to the lower density and viscosity through the same pipeline at the same pressure, hydrogen can be pumped 2.7 times more than gas, but transportation costs will be higher. The energy consumption for transporting hydrogen through pipelines will be approximately 1% per 1000 kgf, which is unattainable for power lines.

Hydrogen can be stored in gas holders with a liquid seal and in reservoirs. France already has experience of underground storage of gas containing 50% hydrogen. Liquid hydrogen can be stored in cryogenic tanks, in metal hydrides and in solutions.

Hydrides can be insensitive to contaminants and can selectively absorb hydrogen from the gas mixture. This opens up the possibility of refueling at night from a household gas network fed by coal gasification products.

Literature

• 1. Vladimirov A. Fuel high speeds. - Chemistry and life. 1974, No. 12, p. 47-50.
• 2. Voronov G. Thermonuclear reactor - a source of hydrogen fuel. - Chemistry and Life, 1979, No. 8, p. 17.
• 3. Use of alternative fuels in road transport abroad. Overview information. Series 5. Economics, management and organization of production. TsBNTI Minavtotrans RSFSR, 1S82, no. 2.
• 4. Struminsky VV Hydrogen as fuel. - Behind the wheel, 1980, Co. 8, p. 10-11.
• 5. Khmyrov V. I., Lavrov B. E. Hydrogen engine. Alma-Ata, Nauka, 1981.

Notes

1. The editors continue to publish a series of articles on promising species fuel and fuel economy problems (see "KJa",).