Development of a digital system for automatic monitoring of the productivity and energy efficiency of road construction machinery

Abstract

Monitoring the operating indicators of road construction machinery in Russian practice relies on hourly fuel consumption norms established for enlarged groups of machines with fixed engine utilisation factors for time and for power. This design took shape before onboard data networks appeared and does not distinguish between shifts worked with different structures of operating modes. The series of standards on worksite data exchange has been adopted in the Russian Federation only in the parts defining system architecture and the data dictionary, whereas the part governing the composition of telematics data has no national status, so that the export of indicators from a machine remains subject to the proprietary formats of onboard equipment suppliers. The aim of the study is to construct a digital system for automatic monitoring of the productivity and energy efficiency of road construction machinery, centred on specific fuel consumption per unit of output as the measured quantity. The author's computational modelling, factor decomposition by the chain substitution method, scenario calculation and comparison with normative hourly rates are applied; the state of a machine is recognised by the coincidence of at least two attributes out of three taken from the onboard network, the hydraulic circuit and the satellite receiver. Calculation for a model fleet of five machines showed that the deviation of actual hourly consumption from the normative value ranges from -12,23% for the motor grader to +18,38% for the asphalt paver, while for the fleet over a season it amounts to only -0,43%. Factor decomposition of the change in specific fuel consumption of the excavator yielded a contribution of the effective time ratio of -0,03421 kg/m³, against +0,02349 kg/m³ for hourly consumption and -0,00425 kg/m³ for technical productivity. The scenario calculation for the earthmoving set produced a reduction of specific energy intensity of output from 12,613 to 11,126 MJ/m³. The mutual cancellation of oppositely directed deviations within the fleet means that the normative hourly rate remains suitable for aggregate planning of fuel costs and loses its controlling power at the level of an individual machine, while the measured quantity of control becomes fuel per unit of output.