This paper presents the comparable research results of the physical-chemical and direct injection (DI) diesel engine properties of diesel fuel and BTL (biomass-to-liquid) blend (85/15 V/V). The energy, ecological and in-cylinder parameters were analysed under medium engine speed and brake torque load regimes; the start of fuel injection was also adjusted. After analysis of the engine bench tests and simulation with AVL BOOST software, it was observed that the BTL additive shortened the fuel ignition delay phase, reduced the heat release in the pre-mixed intensive combustion phase, reduced the nitrogen oxide (NOx) concentration in the engine exhaust gases and reduced the thermal and mechanical load of the crankshaft mechanism. BTL additive reduced the rates of carbon dioxide (CO2), incompletely burned hydrocarbons (HC) emission and smokiness due to its chemical composition and combustion features. BTL also reduced Brake Specific Fuel Consumption (BSFC, g/kW h) and improved engine efficiency (ne); however, the volumetric fuel consumption changed due to the lower density of BTL. The start of fuel injection was adjusted for maximum engine efficiency; concomitantly, reductions in the CO2 concentration, HC concentration and smokiness were achieved. However, the NOx and thermo-mechanical engine load increased. (C) 2015 Elsevier Ltd. All rights reserved.