Wojciech Tutak

CFD MODELING OF THERMAL CYCLE OF SUPERCHARGED COMPRESSION IGNITION ENGINE

Results of modelling of thermal cycle of turbocharged compression ignition IC engine are presented. The object of investigation was a 6CT107 turbocharged auto-ignition internal combustion engine powered by diesel oil, installed on an ANDORIA-MOT 100 kVA/ 80 kW power generating set in a portable version. The performed simulations of the combustion process have provided information on the spatial and time distributions of selected quantities within the combustion chamber of the test engine. The numerical analysis results have been juxtaposed with the results of indicating the engine on the test stand. Modelling of the thermal cycle of an auto-ignition piston engine in the AVL FIRE was carried out within the study. Advanced numerical submodels were used to analysis of combustion process, such as: Extended Coherent Flame Model (ECFM-3Z), turbulence model k-zeta-f, injection submodels with evaporation, collisions, coalescence and other. Intake and exhaust processes were included during modelling. This resulted in a lot of information about the intake, fuel mixing, ignition process and the exhaust process. Results of modelling were compared with results from real engine.

The effect of methanol-diesel combustion on performance and emissions of a direct injection diesel engine

The results of CFD modelling a dual fuel diesel engine powered with both methanol and diesel fuel is presented in the paper. Modelling was performed with 20 and a 50% energetic share of methanol in the entire dose. The analysis was conducted on both the thermodynamic parameters and exhaust toxicity of dual fuel engine. It was found that the various share of methanol influences the ignition delay of the combustion process and after start of main phase of combustion, the process occurs faster than in case of the diesel engine. It was found that the time of 10-90% burn of the fuel is much shorter than it is in the diesel engine. The dual fuel engine was characterized by higher indicated mean pressure in the whole range of diesel fuel injection timings. While analysing toxic exhaust emission from the dual fuel engine powered with methanol, it was found that the rate of NO formation was significantly higher than from the diesel engine. The combustion process in the dual fuel engine occurs more rapidly than in the conventional diesel engine, which contributes to form areas with high temperature, and in combination with presence of oxygen from the air and oxygen bonded in the methanol, promotes the NO formation. In the case of the dual fuel engine, it was found that soot emission was reduced. The engine running with diesel injection start at 8.5 deg before TDC, the soot emissions were more than twice lower in the dual fuel engine, while the emission of NO was much higher.

Modeling of Thermal Cycle CI Engine with Multi-Stage Fuel Injection

This work presents a complete thermal cycle modeling of a four-stroke diesel engine with a three-dimensional simulation program CFD AVL Fire. The object of the simulation was the S320 Andoria engine. The purpose of the study was to determine the effect of fuel dose distribution on selected parameters of the combustion process. As a result of the modeling, time spatial pressure distributions, rate of pressure increase, heat release rate and NO and soot emission were obtained for 3 injection strategies: no division, one pilot dose and one main dose and two pilot doses and one main dose. It has been found that the use of pilot doses on the one hand reduces engine hardness and lowers NO emissions and on the other hand, increases soot emissions.