Improving the reliability of plunger pairs of diesel engines

Abstract

Increasing the efficiency of diesel equipment operation is primarily associated not only with increasing the reliability of its main components, assemblies, joints and parts, but also with reducing costs and fuel consumption during production processes. At the same time, operating experience shows that a significant share of the operating time, the equipment is not fully loaded, often up to 40…50%. The transient and unsteady modes that arise in this case, as well as the design features of the fuel equipment of domestic diesel engines, lead to an excessive consumption of fuel and a significant increase in the unevenness of fuel supply through the engine cylinders to 26…38%. To ensure a minimum clearance in the plunger pair, it is proposed to apply a diamond-like thin film coating based on silicon oxycarbide onto the working surfaces of the parts, which has high microhardness, low friction coefficient, and prevents the setting of contact surfaces by finishing plasma hardening. After applying the technological operation of hardening the working surfaces of the parts by forming a thin film coating, the distribution of the parts over the time of crimping changed so that 82% of the experimental plunger pairs have a hydraulic density exceeding t = 45.7 s with an average value of = 46.7s with a mean square deviation σ = 1.05s. The results obtained during the tests showed that at the nominal speed of rotation of the cam shaft, the cyclic feed of the produced plunger pairs decreased by 2.8%, while in the experimental ones, the decrease in fuel supply was 1.3%, the uneven fuel supply in both cases did not exceed 2%. The predicted resource of the experimental plunger pairs will be 9000 hours, which is 2.25 times more than the resource of serial plunger pairs.