This paper describes research carried out by means of simulation software AVL FIRE. The paper presents detailed steps leading to the implementation of the simulation model of the self-ignition combustion chamber. As a result of the modeling process an animation was created which shows the behavior of the piston and the fuel injection temperature changes depending on the angle of rotation of the crankshaft. The simulation of the phenomena occurring during injection and combustion in the combustion chamber was conducted for the fluid of physical properties and chemical composition corresponding to the properties of diesel fuel and for the fluid with properties corresponding to the rapeseed oil. Simulation results of the carbon black and nitric oxide emission were presented for these two fuels. The aim of this study was to obtain information of the combustion chamber of the diesel engine adapted for feeding with rapeseed oil.