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In late 2003 Moscow hosted an important gathering of international technical experts-First International Automobile Engineering Forum. It was held on the grounds of the Central Research Institute of Automobile and Automotor Engineering (NAMI) which marked its 85th birthday. The list of participants included experts from all corners of Russia, the former Soviet republics and other countries.
by Alexander EIDELMAN, Cand. Sc. (Tech.), head of test laboratory GNTs RF NAMI
The program of the forum was designed to acquaint researchers and engineers with the latest achievements in theory, technical designs and studies in the field of automotive engineering for various applications and of the materials and technologies involved. The forum was also meant to promote exchanges of knowledge and experience and the establishment of business links between specialists from different countries. The agenda included more than 20 presentations and some 20 brief communications. Russian speakers at the forum focused on the following problems and issues: prospects of development and improvement of the automobile industry of this country in general (development of passenger and cargo cars and trucks and bus construction); methods of improvement of our "traditional" and "non-traditional' car engines and search for alternative fuels. Speakers also discussed ecological problems and safety of new fuel systems and improvements in automobile parts and components.
The main report was presented by the NAMI General Director, Dr. Alexei Ipatov. He commented on many changes in our national program "Conceptions for the Development of Automobile Industry of the Russian Federation". He recalled, for example, that as of December 2002 import was discontinued into this country of automobiles and buses with diesel engines with ecological parameters which do not match the European standards. Such cars and trucks are no longer produced in Russia itself. The speaker also outlined a range of measures linked with the utilization of domestic and foreign cars and buses and focused on current requirements for raising the standards of products of our automobile industry.
A number of presentations focused on an analysis of the development of high technologies in the Russian automobile industry. Deputy General Director of NAMI, Dr. Vadim Kutenev, described work on the development of a car engine with
NAMI traverse (crosshead) engine.
regulated compression ratio. This area of research has a promising future as indicated by many calculations and experiments. For gas and diesel engines this new technology holds out a promise of appreciable fuel economy. At the Geneva Show of 2000 one of the entries was car engine SAAB SVC with regulated rate of compression from 8 to 14 points which boasted fuel economy of up to 30 percent in real road conditions. As for NAMI experts, they demonstrated back in the 1980s a model device for regulating fuel mixture compression in which the control gear was located outside of the combustion chamber. This device was planned for both gasoline and diesel engines.
In the latter case it should be possible to boost considerably the input pressure and thus increase engine power. And if it remains unchanged, it should be possible to reduce the working volume (number of cylinders), thus saving the fuel, and also to reduce the mass of the whole engine, which also means its cost.
In a gasoline engine reducing the compression ratio makes it possible to boost input pressure without detonation increasing the per/liter rating. In this way a number of positive factors can be achieved, including reduced fuel consumption at high loads. Economy at low-load regimes is achieved by stepping up compression.
The first domestic model of a 4-cylinder traverse diesel T-01 with regulated compression ratio within the range of 10 - 17 was produced in 1989. In bench tests the engine worked flawlessly for 1,000 h. demonstrating its efficiency and dependability. At the same time experts discovered one more of its advantages-positive effect of regulating the compression ratio on reducing the volume of toxic discharges in exhausts (practically by 2 times).
In 2001 - 2002 German firm Daimler Chrysler ordered four engines VE111.1 on the basis of the commercial Mill engine with spark ignition which was equipped with a traverse engine of NAMI design. These engines demonstrated good performance at high loads: one of them, tested at Stuttgart, worked flawlessly for 1,000 h. By reducing compression ratio it was possible to boost the maximum torque by 30 percent. In the course of its further operation on a 13-stage cycle it demonstrated a significant reduction of fuel consumption as compared with the "base" motor of the same rated capacity but with a crankgear mechanism.
We suggested a new concept of engine in which not only the compression rate, but also the displacement volume of cylinders is guaranted. The traverse NAMI engine makes it possible to increase gradually by nearly 40 percent its displacement volume (the piston stroke) with decreasing the compression ratio by 2 times. Regulating the displacement volume is even more important for an engine than regulating the compression ratio. The thing is that large displacement volume is needed for a car travelling at maximum speed, but this regime does not exceed 10 percent of the whole time of travel. That is
Comparative assessment of the impact of alternative fuels on the ecological parameters of a car engine with forced ignition: 1 - gasoline; 2 - gasoline with products of its conversion; 3 - gasoline plus H 2 ; 4 - liquefied petroleum gas; 5 - compressed natural gas; 6 - methanol plus H 2 ; 8 - synthesis of H 2 gas with CO; 9 - H 2 hydrogen.
why in big cities we need car engines with smaller displacement volume.
NAM I future plans of research provide for the development of engines with regulated compression ratio and displacement volume. When greater power is required, this will be equivalent to a 6-cylinder motor; at lower power levels-to a 4-cylinder and even 3- cylinder ones. In this situation one can expect fuel consumption reductions of 30 - 40 percent.
A comprehensive review of research projects carried by NAMI specialists in conjunction with some academic centers was presented by NAMI expert Dr. Vladimir Kamenev. He dwelled among other things on prospects of using hydrogen fuel for cars. The obvious advantages of this fuel is its abundance in nature and the possibility of its production from renewable raws. H 2 has very high energy content (almost 3 times greater than the traditional petroleum fuels) and unique kinetic parameters. Its products of combustion contain practically no harmful components (carbon oxide and dioxide, carbohydrates, or aldehides). As has been confirmed by tests, even car fuels of mixed hydrogen and gasoline help reduce levels of carbon oxide in exhausts by 10 times, carbohydrates - by 2 - 3 times and nitric oxides by 2 times. Fuel economy of cars using benzohydrogen fuel is 17 percent higher than of gasoline engines.
But a number of physico-chemical parameters of the new fuel gives experts a serious cause for concern. This consists in a reduction of the effective engine power when hydrogen is supplied as gas because of its very low density. And there is also the problem of backfires at loads approaching the maximum and the risk of explosions due to gas leaks caused by metal defects.
With all of these things in mind, NAMI specialists have focused on the development of car engines functioning on mixtures of hydrogen with carbon oxide or dioxide. These are produced directly on board of a car by means of catalytic splitting of methanol with the utilization of the heat carried off by coolant and exhaust gases. The traditional resources of petroleum fuels in nature are dwindling while the production of hydrogen from methanol is ensured on our planet thanks to the large resources of low-grade coal which have been ignored by the industry.
And it should be noted in conclusion that the problem of hydrogen energetics aroused considerable interest on the part of the forum participants. Many of them were in favour of continuing discussions on this subject at the next international meeting of experts in this field.
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