Keywords: V- & W-engines, master and slave connecting rods, equal piston strokes, graph-analytic method of crank gear design.

These authors present graph-analytic method of crank gear design for V- & W-engines featuring master and slave connecting rods in such a manner that strokes of both pistons (attached to master and slave connecting rods respectively) would be equalized. This goal is achieved through proper selection of geometry of crank gear parts and layout. The authors provide formula for design and calculation of equal-stroke crank gear of virtual W-engine.

Keywords: rotary engine, Wankel engine, phased hydrogen injection, fuel economy, lowering hydrocarbon emission.

Rotary engine, invented by Felix Heinrich Wankel, is an alternative to conventional reciprocating engine, and exceeds tha latter in terms of power density. However, thay are not widespread so far because of higher fuel consumption and hydrocarbon emissions. Said drawbacks may be remedied through the injection of free hydrogen. The results of experiments on Wankel engine type VAZ-311 show that hydrogen injection results in higher completeness of mixture combustion.

Keywords: marine engine-generator, load application modes, acceleration, turbo-compound engine, turbine wheel, compressed air injection, transient performance.

The article discusses transient performance of combined two-stage supercharge system. The technology in question includes electric-driven turbocharger rotor and compressed air injection in such a manner that compressed air jet impacts the turbine wheel. Such an approach contributes into completeness of mixture combustion, decrease in noxious emissions, higher acceleration and better quality of electric power during transients.

Keywords: diesel engine, atomization of heated fuel, injector performance, fuel jet parameters.

The idea was tested on a test stand featuring injector fed with diesel fuel heated to 300 °C. The authors calculated geometric dimensioning of hot fuel jet, fuel cone angle, fuel jet velocity and length, and average droplet dimensions. The test results witness to improvement in mixing quality, completeness of combustion and other engine performance characteristics.

Keywords: reciprocating engine, combustion chamber components, carbon deposit, hydrogen-air mixture generator, carbon deposit removal.

The article discusses principal factors that influence carbonization/caking processes in engine combustion chamber. The authors studied possible engine malfunctions caused by extensive carbonization/caking. The offered technology is based on cleaning of combustion chamber components with hydrogen-air mixture injected into engine cylinders. Carbon deposit is removed with specially designed injector unit type Leader-4М. Efficiency of the method in question was validated by tests.

Keywords: 2-stroke petrol engine, piston crown burnout, thermal overload protection.

Burnout of piston crown is an issue typical to high-powered two-stroke petrol engines. One of possible methods to silve the problem is application of heat insulating coating with micro-weld oxidation method. The tests confirmed that such coating effectively prevent piston crown burnout, as it improves heat resistance of the piston without compromising fuel economy and environmental performance of the engine.

Keywords: HyMethShip project, gas engines, reduction in noxious emissions, methanol, decarbonization, synthetic natural gas, «green» hydrogen, hydrogen-activated fuel gas.

The HyMethShip project is a cooperative R and D project funded by the European Union's Horizon 2020 research and innovation programme. The project aims to drastically reduce emissions while improving the efficiency of waterborne transport. The HyMethShip system will achieve a reduction in CO2 of more than 97 % and practically eliminate SOx and PM emissions. NOx emissions will fall by over 80 % below the IMO Tier III limit. The HyMethShip system innovatively combines a membrane reactor, a CO2 capture system, a storage system for CO2 and methanol as well as a hydrogen-fueled combustion engine into one system. Methanol is reformed to hydrogen, which is then burned in a conventional reciprocating engine that has been upgraded to burn multiple fuel types and specially optimized for hydrogen use. The system will be developed, validated, nd demonstrated on-shore on an engine in the range of 1 to 2 MW. The HyMethShip consortium consists of 13 organizations from six EU member states. The partners within the consortium together represent the two dominant parts of the shipping sector value chain, i.e. ship building and operation, they are covering engineering and manufacturing with respect to all technologies that are involved in the HyMethShip propulsion system and they are providing maritime consultancy, especially classification and compliance.

In the mid-sized power generation segment, Jenbacher gas engines are a proven technology provider to utilize high hydrogen gaseous fuels. Coke over gases as well as byproduct gases from chemical processes containing a hydrogen content up to 70 volumes % have been used in various types of engines and accumulated well more than one million operating hours. Hydrogen from renewable sources like wood gasification can contain up to 50 volume % of hydrogen. Hydrogen from electrolysis is typically provided as a 100 volume % and purified H2 fuel and considered as carbon free (green H2) when electricity is produced from renewable sources. One of the main purposes to produce green hydrogen is to add it to the natural gas system, because the natural gas system is seen as a seasonal and large energy storage and necessary for balancing the intermittent electricity production from renewables wind and solar. When hydrogen is mixed with natural gas, the hydrogen content can vary in a wide range. Gas engines have the capability to burn gases with a wide range of hydrogen content, but there are also some challenges with a potentially high fluctuation of the hydrogen content or fast rate of change. The future advantages, the challenges as well as the experience with high hydrogen gases on Jenbacher gas engines will be discussed in this paper. The CIMAC papers are translated into Russian by G.Melnik, PhD.