Kobelco Construction Machinery America recently introduced the SK170LC Acera Mark 8, the company’s newest full-size excavator model. It features an intelligent total control system that senses operator moves and delivers hydraulic fluid where it will be needed, and a power boost option that allows the operator to increase bucket breakout force by 10% and lifting and swing capability by roughly 10% with no time limit.
Powered by a Tier-3-certified 4.5-L Fiat Powertrain engine, the SK170LC Acera Mark 8 delivers 121 hp (90 kW) and 387 lb·ft (525 N·m) at 2200 rpm. The four-cylinder diesel engine features direct injection and an intercooled turbocharger.
Power Mode selection allows the operator to choose between four operating modes based on conditions and task. H-Mode, used for heavy-duty excavation, gives priority to the workload at high speeds, while S Mode, used for standard digging and loading work, provides fuel savings. B Mode, with one-way hydraulic flow, is used for breaker work, and A Mode, with two-way, two-pump flow, can be used for demolition work with crusher/nibbler breaker. Mode changes can be made from the cab using a readout display.
Bucket breakout force can be increased by 10% with Power Boost, a new hydraulic system feature, and a 10% increase in lifting and swing capability is available with the new Heavy Lift feature. Both new features are available on demand with no time limit.
When ambient temperatures dip below 50°F (10°C), a fully automated engine and hydraulic warm-up system kicks in to raise the hydraulic circuit temperature to an optimum 126°F (52°C). Other hydraulic system features include an independent travel circuit that provides dedicated flow for excavator travel, and swing priority, which dedicates power for trenching operations.
Boom- and arm-holding valves minimize drift for accurate positioning, and the standard high-flow valve can be switched between one- and two-pump flow from inside the operator cab. The hydraulic system also uses a high-capacity small-particle filtration system that helps to extend maintenance intervals.
The new excavator has maximum digging depth of 21.4 ft (6.5 m) and a maximum operating mass of 18.9 ton (17.1 t). Enhanced stability and balance are provided by a longer X-frame design, and rollers, sprockets, and travel motors are sealed for protection against debris. A heavy-duty boom and arm are standard features.
A new Intelligent Total Control System recognizes operator moves and provides assistance by delivering hydraulic power where it is needed. This feature also provides the hydraulic sensitivity necessary for fine grading and leveling. The system also includes an Auto-Accel feature that facilitates smooth acceleration by increasing engine speed in proportion to the operator’s movement of the control levers, and an Auto-Decel feature that reduces engine speed after 4 s of operator inactivity.
The excavator’s new cab features provide increased visibility and ergonomically repositioned controls. A seven-position suspension seat features vertically adjustable armrests, and moveable front, top, and side glass panels are designed to provide cross-flow ventilation. For more extreme operating conditions, a high-efficiency/high-output heating and air-conditioning system can be programmed for a climate-control temperature between 61 and 91°F (16 and 33°C). The cab is mounted to the frame with viscous silicone mounts to minimize vibration and shock.
Ground-level service access is provided for filters, batteries, and hydraulics, and the radiator and hydraulic systems can be serviced independently.