Keywords: Moscow State Bauman Technical University, Reciprocating Engine Department, specialty “internal combustion engines”, development of combustion process theory, Bauman Technical University scholar school.

The role of Moscow State Bauman Technical University (Reciprocating Engine Department) in the development of fundamental theory of reciprocating engine up to present time is shown. These authors review investigations carried out by the Department at consequent stages of progress in reciprocating engine building. The works in question have primarily been focused on problems of gas exchange, supercharging, fuel supply, thermal strength etc., and their influence on combustion process.

Keywords: diesel engine, cylinder deactivation, indicator diagram, losses in pump piston strokes, valve timing system, fuel economy.

A mathematical model of 16-cylinder middle-speed marine diesel engine was employed to investigate engine behavior under low load in case of deactivation of 8 cylinders, with varying valve timing. It was shown that fuel economy may only be achieved when all the valves in deactivated cylinders are closed. Indicator diagrams for working and deactivated cylinders have been plotted. Energy losses involved in pump piston strokes are evaluated for various configurations of valve timing in deactivated cylinders.

Keywords: V-engine, quasi V-type engine layout, vee-angle, desaxage, balancing, uniform spark alteration.

The article discusses balancing 4-stroke V- and quasi V-type reciprocating engines, differing in vee-angles, angular offset of adjacent crankpins, and desaxage. Ways are offered of how to balance inertia forces from rotating and reciprocating masses as applied to engines of various cylinder arrangement.

Keywords: high-speed small diesel engines, methanol, ethanol, fuel-spirit emulsion, ignition delay, combustion, heat release, analysis of indicator diagram.

Use of fuel-spirit mix (based on methyl and ethyl spirits) for firing high-speed small diesel engines is recommended. Methods of preparation and usage of fuel-spirit non-coalescing emulsions are examined. The results are presented of the research into operation of high-speed small diesel engine type CH11/12,5 on methanol-fuel and ethanol-fuel emulsions. Indicated values, combustion performance characteristics and heat release parameters yielded are compared with those of diesel engines.

Keywords: Low-power boilers, high-temperature fluidized bed, off-gas recirculation, layer temperature, hybrid power plants, transients.

The article presents the review of mathematical models for analysis of transients in low-output boilers featuring high-temperature fluidized bed. Also presented is a comparison between calculated and experimental curves of fluidized bed layer temperature vs. disturbances caused by changes in fuel and air flows. A mathematical model is developed suitable for simulation of combustion in low-output boilers operating on coal, peat and woodchips, with off-gas recirculation, as well as conjoint operation of a diesel-generator with a solid-fuelled active waste-heat boiler.

Keywords: Marine gas engines, lean fuel/air mixture, misfiring, knocking, unburned methane slip, gas permeation membrane, separate flow with different O2 content, hidrogen additions, emission decrease.

This review is dedicated to two new technologies targeted at the improvement in combustion performance as applied to marine diesel engine operating lean fuel/air mixture, so as to reduce unburned methane slip and extend engine operating range.
A group of researchers from Kyushu University, Japan, offered a new method of unburned methane slip reduction based on a gas permeation membrane (GPM) that is inserted between a compressor and a charge cooler. The membrane splits charge air into two flows. Oxygen-enriched air (OEA) permeates to the secondary side of the membrane, while charge air turns into nitrogen-enriched air (NEA) building upstream of the membrane. NEA and re-compressed OEA flow into a combustion chamber thorough fully separated intake ports. The OEA-based premixture biased toward the cylinder wall will decrease the quenching distance and resulting methane slip. The NEA premixture around the cylinder centre will control the knock tendency keeping the same level of NOx emission.
The international research team from Tecnische University Munchen and Kyushu University made an investigation into combustion process in marine diesel engine operating lean fuel/air mixture added with hydrogen (H2) so as to reduce unburned methane slip. Engine operation test for emission performance has been carried out on single-cylinder research gas engine for two fuel mix compositions containing H2 =10% and 30 % (referred to as HNG10 and HNG30 respectively), pure methane being used as a baseline case. It was found that use of HNG10 fuel mix results in decrease in CO and THC emissions without compromising NOx emissions. Use of HNG30 fuel mix allows to substantially extend the misfire limit, however, it entails the risk of appearance of self-ignition nuclei prior to the spark discharge, and therefore restricts the engine operation.
The CIMAC papers are translated into Russian by G.Melnik, PhD.