One of the solutions to meeting the stringent emission regulations was to equip a crane with an exhaust gas aftertreatment device used in motor vehicles, such as buses and trucks. This was the very first attempt for the cranes. “Engine manufacturers impose various conditions and restrictions on the installation of an exhaust gas aftertreatment device. For this reason, we used our ingenuity to figure out how to configure all the devices ranging from intake to exhaust systems,” Tanji said. By closely communicating with an engine manufacturer, they aimed to achieve the optimal location of an exhaust gas aftertreatment device so that it can deliver full performance.
Moreover, as the crane’s engine load and way of use are completely different from those of motor vehicles, a control system that has been optimized for cranes was needed to control the exhaust gas aftertreatment device. “By holding multiple discussions with the engine manufacturer and conducting tests repeatedly, we were able to devise the best control pattern for cranes,” said Hideaki Ishihara, who designed electric control as a whole for the G series.

Needless to say, efforts to address environmental concerns were not confined to the installation of an exhaust gas aftertreatment device alone. The team came up with a new “G-mode” energy-saving system that made it possible to reduce fuel consumption by up to 25 percent, and mounted it on the crane. This system incorporates three features: the “G-winch,” which enables lifting and lowering at the highest line speed without revving up an engine; the “G-engine,” which can ensure higher fuel efficiency for the same amount of work; and the “Auto Idle Stop (AIS),” which allows the engine to stop automatically while idling. Thanks to the synergic effect of these three, the G series’ environmental performance has been boosted significantly.
Expectations on the environmental performance are running high also in Japan. “Given that oil prices have recently been unstable, I believe that added value resulting from energy savings is high,” commented Akira Takayama of the Japanese Sales Department.