To the choice of the truck-tractor type for heavy duty semi-trailer

Abstract

Investigation of the influence of design parameters on traction-speed properties, productivity and efficiency of rolling stock is a prerequisite for the improvement of transport services. Correct, grounded by research and experience, combining the parameters of trucks, semi-trailers and trailers based on the tasks that the carrier faces, the conditions of rolling stock operation are powerful means to increase its productivity and efficiency. The choice of the truck-tractor and trailer for freight transportation should be made based on the safety of their constructions, as well as taking into account the performance characteristics, conditions under which the transportation is planned, goals set by the organizers of transportation matching. The basis of comparison of truck-tractors on the parameters of traction characteristics is the average speed on the road, since it determines the transport performance of the heavy-duty vehicle. Calculation of the traction characteristics of road trains is performed by solving the differential equation of motion. The total fuel consumption on the route is determined on the basis of a mathematical model of the engine, which allows setting the value of the hourly fuel consumption of the engine, depending on its mode of operation - according to the known frequency of rotation and torque on the engine shaft (or the coefficient of engine power utilization). This dependence can be constructed on the basis of the twelve known (reference) values of hourly fuel consumption of the engine measured at engine tests according to UN Regulation No. 49 under the conditions of the ESC test cycle. When determining the fuel consumption on the operating route, the idle mode is not used. 

It is established that according to the indicators of traction characteristics and fuel efficiency, vehicles consisting of semi-trailer with DAF, MAN, IVECO, SCANIA and Volvo truck-tractors are almost identical for the chosen engine power settings and transmission ratios. Improvement of traction characteristics and fuel efficiency should be done be optimizing the parameters of the "engine-transmission" system of tractors.