BTB 37: EHS and the new E-series skidders
Published on: Tuesday 1st July 2014
Early in 2014, Tigercat released the E-series skidders. Available in North America and Europe, the 620E, 630E and 635E skidders are powered by the Tigercat FPT N67 Tier 4i engine. The 620E is rated at 164 kW (220 hp) and the two larger models at 190 kW (260 hp).
Tigercat FPT engines meet the stringent Tier 4 emission levels without the need for variable geometry turbochargers, an EGR system, a higher capacity cooling system, an intake throttle body or a diesel particulate filter. As a result the engines offer improved reliability and lower long-term maintenance costs. The biggest benefit for Tigercat machine owners is that the engines are fully supported by Tigercat and the Tigercat dealer network, including all parts, service, warranty and technical support.
Tigercat’s other skidder markets including Australia, New Zealand, Russia and South America will continue to receive Cummins Tier 3 equipped D-series skidders for the foreseeable future.
The 620D/E and 630D/E are suited to the vast majority of the world’s high production skidding applications — commonly used in clear fell and plantation thinning applications, steep ground and soft soil. The six-wheel drive 635D/E with its long wheelbase, low-ground pressure and massive grapple is designed for long hauls, extremely heavy loads and very soft or steep terrain. The 635D/E is also approved for use in demanding, high duty cycle ground scarification applications.
EHS option for 620 series
Tigercat’s EHS (efficient high speed) drive system is similar to the standard hydrostatic drive system in that the two variable displacement motors are input into the Tigercat transfer case. Front and rear output shafts are connected directly to the front and rear axles. However the similarity ends there. EHS is capable of providing the tractive effort of the deepest gear ratio offered in Tigercat’s standard transfer case as well as the top speed of the shallowest gear ratio offered in the standard transfer case. This is accomplished with more sophisticated computer logic and the ability to take one of the drive motors offline when high tractive effort is not required. In this case, all pump flow is directed to one hydraulic motor, increasing both travel speed and motor efficiency. When operating conditions demand high tractive effort, both hydrostatic motors are working. When tractive effort requirements are minimal — for instance, when traveling empty — all of the pump flow is directed to one motor for higher travel speeds. Tigercat is now offering the EHS option on the 620D/E series skidders. Initial field studies indicate excellent production and fuel economy in relatively flat terrain, where the machine is able to operate fully loaded on one drive motor for a significant portion of the duty cycle. Warren Brantley, owner of Oconee River logging LLC in Georgia, has been running an EHS equipped 620E since early March. Pulling nine tonne (10 tn) drags on flat terrain, the machine is able to run on one motor the majority of the time and fuel consumption is positively impacted at around 20 L/h (5.4 gph) with very little engine idle time. Of the 620E, he says, “Tigercat listened to what we wanted and built it. That’s the best thing ever to come out of Canada.”