The ever increasing pressure for more efficient engines, with lower production cost and time has led to the development of advanced simulation tools. Likewise, the experimental development of combustion systems has benefited from computational tools while reducing the necessary experimental time. This paper describes the analysis of combustion performance of a Diesel engine normally used on generator sets. A detailed heat release analysis is performed through one-dimensional simulation software and experimental results, enabling a comprehensive description of combustion parameters of the engine through a simplified study. Brake and indicated values were obtained and analyzed to point out efficiency maps and show the effectiveness of the simulation tool in engine and combustion systems development.