Komatsu's
Dig with diesel, swing with electricity by x INNOVATIONS 2010 by x KOMATSU HYBRID PC200LC-8 B ack when diesel was cheap and carbon was something that accumulated inside your fi replace, nobody cared about how much fuel it took to move a ton of dirt. But in this new century with uncertain fuel prices, fi erce debates over global warming and the EPA regulating engine emissions (and perhaps even carbon dioxide) the major heavy equipment companies have pushed their engineering staffs to fi nd sustainable paths into the future. For Komatsu, the beginnings of that sustainable future came into focus in the late 1990s when company engineers started develop-ing an electric swing motor. In 2001, the engineers took the prototype to a marketing team and the combined teams began the process that would, after further engineering innovations, result in the introduction of the Hy-brid PC200LC-8 excavator that uses both hydraulic and electric power. Komatsu had introduced a hybrid forklift in 2007 that offered a 20-percent reduction in energy use compared to standard electric powered models. There are more than 400 of these units operat-ing in Japan today. But a 20-ton excavator with its massive torque requirements and 30,000 pounds of digging force was another story. Getting the feel right The main engineering challenge was to combine the hydraulic and electric sources of power in a way that would give operators the same performance and feel of an all-hy-draulic machine. In a conventional excavator, the dig and swing actions are powered by the same hydraulic system. In Komatsu's hybrid sys-tem the boom, arm and bucket still draw power from the hydraulics, but the swing motor that rotates the upper structure uses electrical power. To get the two sources of power to mesh seamlessly Komatsu A four-cylinder diesel engine drives the hydraulics and an electrical generator pumps energy into an ultra-capacitor that powers the swing motor. by Tom Jackson January 2010 Â EquipmentWorld.com 22 2010 Innovations.indd 22 12/21/09 1:26 PM