Abstract
The work presented here arises from an intuition corresponding to a completely different approach to reduce pollutants: altering the fuel used in the engine rather than further complicating the engine. Indeed, in recent years, diesel engines have undergone a surely remarkable evolution, dictated by the need to fulfill the antipollution regulations that came into force in the meantime. Focusing the attention on agricultural tractors, however, the result was the introduction of a number of devices that are certainly effective but cost expensive; they also require maintenance and occupy quite room under the bonnet, which is already heavily crowded. This preliminary experimental investigation has made use of a commercial diesel engine, as representative of the diesel engines used in agriculture, and of a complete equipment for testing the engines (dyno, gas analyser). This engine was first fuelled with commercial diesel oil and then with biodiesel coming from agricultural residues. It has been observed that the performance drop (expressed in terms of power and torque) is substantially not relevant for the utilizer, while it is certainly significant and very encouraging the recorded drop in NOx emissions in the exhaust gases.