ABSTRACT

Cable yarding is an inherently expensive extraction technology, but the mainstay for mountain forest management. Fuel cost represents a considerable share of total harvesting costs. Energy-recuperating, electrical slack-pulling carriages (EC), which recuperate energy during lateral yarding and store it as electrical energy in super-capacitors for powering slack-pulling during the subsequent yarding cycle have emerged only recently. Fuel consumption of cable yarding is expected to be lower when ECs are employed compared to working with conventional, diesel engine-powered slack-pulling drive (DC) carriages. To determine if reality matched expectations, a time and motion study was conductedduring which fuel consumption was extracted from the engine control systems using custom-made dataloggers for an uphill whole tree yarding operation in Austria. Average productivity was 21.9 m³ per productive system hour excluding delays (m³ PSH₀⁻¹) at 0.89 m³ average tree volume and 58.4 m average yarding distance. Productivity was modeled as a function of average tree volume, yarding distance and lateral yarding distance. Average fuel consumption was 1.27 ± 0.97 l m⁻³ (DC) and 0.88 ± 0.56 l m⁻³ (EC). In the DC treatment, the carriage engine accounted for 9% of the total fuel consumption. Modeling revealed that fuel consumption depended on average tree volume, yarding distance, lateral yarding distance and carriage type as originally postulated. The latter effect interacted with that of average tree volume and EC’s advantage in fuel consumption was limited by a break-even average tree volume. In conclusion, the EC has the potential to improve profit margins in small-tree operations through lower fuel consumption.

摘要

电缆堆场本身就是一种昂贵的提取技术，但却是山地森林管理的支柱。燃料成本占总收割成本的很大一部分。能量回收式电动牵引车 (EC)，它在横向堆料期间回收能量并将其作为电能存储在超级电容器中，以便在随后的码垛周期中为松弛牵引提供动力。与使用传统的柴油发动机驱动的松弛牵引驱动 (DC) 车厢相比，使用 EC 时，电缆堆场的燃料消耗预计会更低。为了确定现实是否符合预期，进行了时间和运动研究，在此期间，使用定制的数据记录器从发动机控制系统中提取了奥地利上坡整棵树堆场作业的燃料消耗。³每生产系统小时，不包括在 0.89 m ³平均树木体积和 58.4 m 平均码放距离的延迟 (m ³ PSH ₀ ^-1 ) 。生产力被建模为平均树木体积、码放距离和横向码放距离的函数。平均油耗为 1.27 ± 0.97 lm ^-3 (DC) 和 0.88 ± 0.56 lm ^-3(欧共体)。在直流处理中，马车发动机占总油耗的9%。建模显示，燃料消耗取决于最初假设的平均树木体积、码放距离、横向码放距离和车厢类型。后一种影响与平均树木体积的影响相互作用，EC 在燃料消耗方面的优势受到盈亏平衡的平均树木体积的限制。总之，EC 有可能通过降低燃料消耗来提高小树操作的利润率。