FUZZY LOGIC CONTROL TO OPTIMIZE THE EFFICIENCY OF COMPRESSION IGNITION ENGINES USING DIESEL OIL AND NATURAL GAS 2006-01-2903
It is known that internal combustion engines have low efficiency and produce air pollution. Among the less polluting fuels this work uses the natural gas. It is evaluated a bi-fuel Diesel engine, powered by Diesel oil and natural gas aiming at improving the overall efficiency. In the tested engine the energy comes from natural gas combustion. The Diesel oil just generates the pilot ignition for the combustion process. Diesel oil is replaced by natural gas, increasing so the efficiency of combustion. Initially, the engine was tested with Diesel oil to obtain reference parameters for their nominal characteristics. After that, tests were carried out with distinct proportions of Diesel oil and natural gas at different angles of injection progress. It was obtained the best performance for 22% of Diesel oil in relation to the maximum debit of the injector pump and 13 L/min of natural gas with original angle of injection progress (21º). The average power was increased by 14% and the specific consumption, in economic terms, was reduced in 46% regarding the initial reference. An electronic manager was developed to inject the natural gas. This controller uses a fuzzy algorithm, implemented in a microcontroller to manage the volume of gas supplied to each injection cycle. The injection angle is also monitored by the system. The topology proposed in this paper can be used for bi-fuel Diesel engines increasing the efficiency, reducing the fuel consumption and the pollutant emissions.