Comparing Fuel Consumption During Timber Forwarding With and Without Traction-Assist Winch

Nearly 20 years ago, the first traction-assist winches were introduced to the market. This enabled an expansion of fully mechanized harvesting operations to steeper slopes. Concurrently, both productivity and occupational safety in steep terrain could be improved. The operating principle of traction-assist winches is to transfer driving and braking forces from the machine to the winch cable and thereby significantly reducing slippage during driving in inclined terrain. In numerous cases this has shown to minimize rut formation. On the contrary, little research has been conducted on the impact of using a traction-assist winch on the fuel and time consumption. Therefore, this study aims to investigate how the deployment of a T-WINCH 10.2 as traction assistance affects overall fuel and time consumption during extraction using a Komatsu 875. For the field test, two neighboring skid trails were selected, which had only minor terrain variations and were accessible also without a traction-assist winch. The average slope of the trails was 39%. The skid trails were driven on multiple times by an experienced machine operator, both with and without the winch assistance, loaded and unloaded. The experiments were conducted according to a predefined test procedure to randomize uncontrollable influences. The data was collected using CAN-BUS loggers to capture machine data from the forwarder and winch. The accuracy of this data was validated beforehand through refueling tests. It was found, that the fuel consumption derived from the CAN-BUS data deviated by less than 1% from the values determined through weighing. Thus, it can be concluded that the fuel consumption obtained from the CAN-BUS data is reliably determined. The data analysis revealed an average fuel consumption of 21.9 l/h (Komatsu 875: 15.89 l/h; T-Winch: 6.01 l/h) for the forwarder using the winch assistance. For the forwarder without assistance, the average fuel consumption was 18.45 l/h. Thus, the average additional consumption per hour when using the winch was 3.45 l/h (+18.7%). In addition to its impact on fuel consumption, the winch also affects the work cycle time. An average time saving of 8.5% per load was observed, with the most significant time reductions occurring travel loaded uphill, representing a saving of 29.4%. In the overall result, and focusing on cubic meters extracted, an average consumption of 0.28 l/m3 was observed, resulting in an increased overall consumption of 10.8%. In conclusion it was shown, that even though the use of the T-Winch results in a reduction in fuel and time consumption of the Komatsu 875, this savings cannot compensate for the additional consumption caused by the winch itself. Ecological influences of traction-assist winch usage, which can also manifest positively, were not considered in this study.