The influence of the design features of the cooling system on the engine life of construction machinery

Abstract

The efficiency of the cooling system of internal combustion engines is a critical factor determining their operational life and reliability of operation under conditions of intense loads of construction machinery. Modern trends in boosting engines in terms of power while tightening environmental requirements actualize the problem of optimizing the design solutions of cooling systems to ensure maximum service life of power plants. The paper presents a comprehensive analysis of the influence of architectural features of cooling systems on the durability of engines of construction machinery based on experimental studies of 347 units of various types of equipment. The study covers the period of operation of up to 15,000 operating hours with detailed monitoring of the parameters of the thermal condition and wear characteristics. It was found that optimization of the cooling system design makes it possible to increase the maintenance life by 23-31% while reducing specific fuel consumption by 4,2-6,8%. The critical dependences between the geometric parameters of the cooling channels, the intensity of the heat sink and the rate of accumulation of fatigue damage in the material of the cylinder piston group are revealed. The results of numerical modeling confirm that the unevenness of the temperature fields due to the design flaws of the cooling system leads to local thermomechanical stresses exceeding the limit of long-term strength of the material by 15-25%. The developed methodological approaches to the design of cooling systems ensure a reduction in the maximum temperatures of the cylinder piston group parts by $35-42^{\circ}C$, which correlates with an increase in the service life before the first overhaul by 2800-3500 operating hours. The practical significance of the results is confirmed by the successful testing of the proposed solutions at construction machinery enterprises with an economic effect of 1,8-2,3 million rubles per unit of equipment per life cycle.