Methodology to analyse farm tractor idling time

Actual in-service damage to tractor engines could be different from that predicted according to other estimates due to the difficulties in evaluating all the information necessary to completely define the mission profile. Among the different parameters which could be measured or estimated, the idling duration is one of the most influential factors in the calculation of in-service damage. In this paper, a methodology to estimate the idling time from signals recorded through a data logger interfaced to the vehicle-bus is proposed. Through statistical methods, the idling duration distribution was identified for a fleet of 61 New Holland T9 farm tractors used in Europe and in North America. Starting from these distributions the percentiles have been estimated. The recorded values of idling duration range from 5% up to 50% and the average value is about 20% of the tractor life. Furthermore, 97.5% of the analysed tractors run under idling condition for greater than 10% of the whole life of the machine. All tractors have made at least a stop shorter than 1920 s, while not all have made a stop longer than 1920 s. From the analysis, tractors located in areas with extreme temperatures have run under idling conditions for a longer time to keep the cab comfortable or to maintain the engine on temperature. This data confirms the importance to considering the geographical distribution of the machines and the necessity of performing a wide acquisition campaign to define the tractor mission profile.