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HISTORY OF TECHNOLOGY, TECHNOLOGY, OBJECTS AROUND US
Cars on alternative fuel. History of invention and production
Directory / The history of technology, technology, objects around us According to experts, all known oil reserves on Earth will last for no more than fifty years. Gasoline is becoming more expensive, and today they are not trying to replace it with anything. And liquefied natural gas, and all kinds of synthesized gases and liquids, in particular alcohol, which is driven from a variety of raw materials from cane to orange peels. Almost all of these fuels are less harmful to the environment than gasoline, but car exhaust is still not made harmless. Under certain conditions, an electric car could fundamentally solve the problem of air pollution by motor vehicles. To do this, not only the operation of its energy source, but also the production of this source and even waste disposal should become environmentally friendly. So far, the battery usually used in electric vehicles does not meet these requirements. “And yet,” as K. Klimov writes in the journal “Science and Life”, “in recent years, the electric car has been used much more widely. Thanks to the developments of the largest automotive companies in the world, the disadvantages of the battery - weight, dimensions, the need for frequent recharging - have somewhat decreased. Recently, For example, the German company BMW has demonstrated a new electric car based on a sodium sulfide battery, which, according to the company, takes just 96 seconds to accelerate from a standstill to a speed of 20 kilometers per hour, a maximum speed of 130 kilometers per hour, and the range between recharging reaches 270 kilometers. But such an electric car will not find mass use in transport, since the operating temperature of the sodium sulfur battery is about 350 degrees Celsius. Both this temperature itself and the need to maintain it during battery operation with the help of special heaters make it explosive and fire hazardous " . There are more and more "electric" cars on public roads every year, and reports of new developments in this area do not leave the pages of magazines and newspapers. Until recently, the development of electric vehicles was constrained by the low parameters of current sources. For many years, the traditional lead-acid battery served in this capacity. In addition to other serious shortcomings, it limited the car's mileage before recharging to about 150 kilometers. As a result of the modernization, the battery was lightened and the acid in liquid form was replaced with a less dangerous gel. And yet, there is no need to wait for a breakthrough in this direction, the energy "packing" density and the power of acid batteries have almost reached the theoretical limit. But replacing lead with nickel, it was possible to create a whole range of new batteries - nickel-cadmium, nickel-hydrogen and nickel-zinc. They compare favorably with lead-acid batteries. They are characterized by durability, insensitivity to frost, the ability to quickly recharge. True, they are more expensive, and some types of batteries still have to be topped up periodically. Nickel-metal hydride systems are recognized as the most promising today. It is they who have the maximum specific indicators, and the self-discharge is acceptable: fifty percent of the capacity per month. Six years have passed since these batteries were first used in the automotive industry. During this time, experimental electric vehicles have traveled millions of kilometers on the roads, proving their suitability for operation at temperatures from minus twenty-five to plus fifty degrees. Here is what the magazine "Behind the wheel" writes: "The obvious advantages of nickel-metal hydride systems, first of all, include the almost doubled mileage until the next recharge - up to 250 kilometers compared to a lead acid battery. And in 1996, a record was also recorded : the Solectria-Sunrise car, driven only by an electric motor powered by nickel-metal hydride batteries, traveled over 600 kilometers in one go! During tests, it was found that nickel-metal hydride systems can withstand more than 10 charge-discharge cycles, which is comparable to a mileage of 80 kilometers. All this will be told to the buyer with pleasure, for example, in the Toyota showrooms in the USA and they will immediately offer to ride on the brand new RAV-4EV off-road vehicle. Hidden under its floor are 24 nickel-metal hydride batteries that power an electric motor with a capacity of 67 hp. This is enough for a fairly frisky acceleration (0-100 km / h - 18 seconds), and the maximum speed had to be limited to 125 km / h. I liked it - "RAV-4EV" can be bought right there for $42000. Something does not suit? Do not be upset - after all, the choice of electric vehicles by Toyota is not limited. There's the Honda EV Plus, the Ford Ranger EV, and the Nissan Altima EV - the list goes on. Europeans liked the Peugeot-106 Electric and Citroen-AX Electric, and the Bombardier NV micromobile is called upon to impress fashionable youth, for which they ask almost less than for some VAZs.
Electric vehicles, among other things, gave birth to a new, extremely promising direction - the so-called hybrid cars. A hybrid scheme is a combination of an engine running on the usual fuel (gasoline or gas, but more often on diesel fuel) and an electric motor. A typical representative of this particular group, the Toyota Prius, is one of the most commercially successful examples. Last year, more than ten thousand buyers preferred this model, and this, you see, already means something. In the US, in order to stimulate the auto industry to actively search for new solutions, a law has been passed requiring every company to have at least one model of an electric vehicle in its program by 2003. Otherwise - a ban on trade. Among the main contenders for the title of "the main competitor to internal combustion engines" today are cars with fuel cells. The fuel cell first saw the light of day in 1839, when the English physicist William Grove generated electricity from the electrochemical reaction of hydrogen with oxygen. The topic began to be developed intensively in the 1960s and 1970s, when fuel cell engines were first used in the space industry. How does the conversion of chemical fuel energy into electrical energy usually take place at thermal power plants? First, the thermal energy released during combustion is converted into the kinetic energy of the steam. Then the steam energy on the turbine rotor is converted into mechanical rotational energy. And, finally, in the windings of the generator, mechanical energy becomes electrical. Losses are inevitable at every stage. In a fuel cell, the chemical energy of the fuel is immediately transformed into electrical energy. A fuel cell, or an electrochemical generator, is a technical device where the fuel oxidation reaction takes place, during which electricity is generated. The fuel can be hydrogen, alcohol, ammonia and hydrocarbons (natural gas, oil), and the oxidizer (combustion is an oxidation reaction) is oxygen, nitric acid, etc. The design of the fuel cell is simple. This is a vessel with an electrolyte (an aqueous solution of acid or alkali), two porous electrodes (an anode and a cathode, as in a battery) and tubes for supplying fuel (to the anode) and oxidizer (to the cathode). At the anode, hydrogen molecules break up into atoms, which lose their electrons, become positive ions, and go into the electrolyte. The anode that has lost ions acquires a negative charge with respect to the other electrode, and free electrons move towards the latter along the external circuit. There they combine with oxygen atoms - negative ions are formed. The latter pass through the electrolyte and combine with positive hydrogen ions. This creates a closed circuit through which an electric current flows, and the fuel cell becomes an electric generator. In addition to electricity, it also produces a by-product - distilled water. A single fuel cell produces a voltage of about 1,5 V. To obtain a higher voltage, the cells are connected in series with each other to form batteries.
The time of continuous operation of the battery depends on the reserves of fuel, oxidizer and wear (oxidation) of electrode materials and is 1000 hours in existing installations. Therefore, they are now used only for power supply of autonomous consumers, such as deep-sea vehicles or near-Earth space stations. Today, hydrogen-oxygen fuel cells are most commonly used. However, air-aluminum fuel cells are much more efficient, in which a porous carbon-graphite plate with air oxygen entering it serves as the cathode, and an aluminum alloy plate as the anode. Oxidation proceeds with an efficiency of eighty percent, and a kilogram of aluminum "burnt" at room temperature is capable of delivering approximately as much energy to the external circuit as a kilogram of coal gives when burned in air at a very high temperature. “Such sources of electricity have many advantages: simplicity of design, complete safety of operation, and good specific energy characteristics,” writes K. Klimov in his article in the journal “Science and Life”. material, which is determined mainly by the energy intensity of the production process.This disadvantage should, however, decrease over time, and thanks to the latest developments of the A.A. Baikov Institute of Metallurgy of the Russian Academy of Sciences, it will quite possibly be completely eliminated, and, moreover, in the very near future . Institute specialists have developed a new and highly effective method of so-called multicomponent chemical reactions. In a specially selected medium, which has both ionic and electronic conductivity, multiple and evenly distributed microelectrode (as they are called) electrochemical reactions occur at a certain temperature. With their help, many of the known elements can be obtained in pure form, including metals, and in particular aluminum. This is already being done today, but so far in laboratory conditions, and ordinary soil clay or any ore raw material containing alumina is used as a raw material. Aluminum oxide (the main component of alumina) is converted with calcium chloride to aluminum chloride and sent to the reactor. Vapors of metallic sodium, which is obtained by heating soda with coal, also enter there. Thus, a sodium solution mixed with aluminum melt is formed in the reactor, and conditions are created for the simultaneous occurrence of multiple redox reactions. As a result of these reactions, liquid aluminum is obtained. Some of these reactions go with the release of heat, which, of course, reduces the energy intensity of the production process. The production itself turns out to be both simpler and cheaper than traditional electrolysis, and also much cleaner environmentally.” If the industry manages to master the new technology for producing aluminum, then both it and its alloys will become much cheaper. This will solve two problems at once. First, it will speed up the solution of the problem of automobile fuel. Secondly, the car body can be made from a lightweight and non-corrosive material, which will lead to a significant reduction in its weight. And reducing the weight of the car will reduce energy consumption when driving. Air-aluminum fuel cells are already being produced in many countries, including Russia. But the Japanese showed particular interest in them. They produce them in the tens of millions a year. The Japanese do not hide their intentions to soon launch the production of electric vehicles on aluminum. Mercedes-Benz (now Daimler-Chrysler) is considered one of the pioneers in introducing this technology into the automotive industry. In 1994, on the basis of the van, she built a prototype car with fuel cells "Neckar-1". Two years later, a V-class passenger car was equipped with a similar power plant. A new step was the premiere of Nekar-3, which uses methanol as fuel. As the magazine "Behind the wheel" writes: "A distinctive feature of this model is the absence of batteries for storing energy. The process in the system occurs directly - when you press the accelerator pedal, about ninety percent of the maximum power is available in less than two seconds. As a result, a decent accelerating dynamics of the car , quite comparable with conventional diesel or gasoline models.As for fuel, the use of methanol does not require any special security measures, and the process of refueling a car is not much different from filling a tank with gasoline.By the way, the Neckar-3 fuel tank holds 38 liters fuel, on which the car is able to overcome 400 kilometers.This, it would seem, is already a good result beat "Neckar-4" - the next and certainly not the last prototype on the way to mass production. In addition to the Daimler-Chrysler concern, research and development of vehicles with fuel cells are carried out by many companies - Ford and Volvo, Nissan and Renault, Mazda ... And although there are still a lot of problems to be solved on the way According to Daimler-Chrysler forecasts, this company alone will be able to produce from 40 to 100 fuel cell vehicles in the next 4-5 years by the serial production of such vehicles. Guy Negre, the designer of "Formula 1", founded the company MDI, where he began to create a new engine - a hybrid one. In it, in particular, air can act as fuel! The Negro decided to abandon the classical scheme, when all actions take place in one cylinder. He uses two: one with a volume of 270, and the other with 755 cubic centimeters. The cylinders are connected by valves with a spherical chamber of 20 cubic centimeters. When the engine is running on gasoline, the small cylinder sucks and compresses the combustible mixture, which is then pushed into the combustion chamber. There it is ignited by a spark discharge and burns out at a constant volume (both valves of the chamber are closed). Then the valve leading to the expansion cylinder (large) opens. Such a scheme has a number of advantages. The combustion phase is separated from the expansion and is much longer than in a conventional engine, so the new engine can run on extremely lean, slow-burning mixtures, it does not need a silencer, and exhaust toxicity is comparable to ordinary city air. When working on compressed air, the processes in the engine practically do not change. It seemed that the goal was achieved, but Guy Negro set to work on a new engine and a new car. He called it TOP - "zero pollution taxi". This name reflects the concept: this car will not be fueled with gasoline, only with compressed air. “Even in the project, the car aroused great interest not only among specialists,” the Za Rulem magazine reports, “but also among those in power. So, in Mexico, the parliamentary commission on transport became interested in the developments of French engineers, and after the Mexicans visited Brignole signed a contract for the gradual replacement of all 1997 taxis in Mexico City, the most polluted capital in the world, with cars with a clean “exhale.” The TOP models will be assembled on the spot - the French will build a turnkey plant overseas. We foresee objections: they say, in order to pump air into cylinders, energy is needed, and power plants are also sources of pollution. The authors of the project calculated the final efficiency in the chain "refinery - car" for a gasoline, electric and "air" car: 9,4, 13,2 and 20 percent, respectively - "air" is in the lead by a noticeable margin. The new motor largely repeated the already run-in hybrid. However, now the pistons have become longer "hang" in dead spots (80 percent of the time) thanks to special slipping clutches on the crankshaft. It is not outside air that is sucked into the cylinder, but part of the exhaust. There are no ignition systems, fuel injection, gas tank. But under the bottom, four carbon (almost weightless!) 50-liter compressed air tanks are neatly located. Its reserve (200 liters at 200 atm.) Is enough for 500 kilometers at a speed of 40 kilometers per hour or 100 kilometers at 90 kilometers per hour. During braking, energy is recovered - the high-pressure compressor pumps outside air back into the cylinders. There are two ways to "refuel" a car. From a high-pressure air line - 2-3 minutes (at Western prices for only one and a half dollars) or from the mains: the same compressor will inflate the cylinders in 4 hours - faster than charging an electric car. Speaking of electric vehicles, one cannot but mention Tesla Motors. It is an American car company from Silicon Valley focused on the production of electric vehicles. Named after the world famous electrical engineer and physicist Nikola Tesla. The company's first car was the Tesla Roadster sports car. Its official presentation took place on July 19, 2006 in Santa Monica, California.
Tesla is engaged not only in the production of cars, but also in the construction of the Supercharger network - stations for charging electric vehicles. Author: Musskiy S.A.
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