Heavy Excavation
HD Hyundai has announced its largest Stage V crawler excavators, with the arrival of the 80-tonne HX800A L and the 100-tonne HX1000A L. These heavy-duty machines have been designed to operate in a mines and quarries, as well in bulk earthmoving for construction and infrastructure project applications. They deliver maximum productivity with reduced total cost of ownership (TCO).
Both excavators are powered by the latest EU Stage V-compliant Perkins diesel engines, delivering class-leading power and economy. The HX800A L uses the six-cylinder Perkins 2506J, providing 400kW (539hp) at 1,800rpm and 2,468Nm of torque at 1,400rpm. The larger HX1000A L is powered by the Perkins 2806J, offering 460kW (629hp) at 2,000rpm and 2,952Nm at 1,300rpm.
The engines are equipped with a combined exhaust treatment system, incorporating a Diesel Particulate Filter (DPF), a Diesel Oxidation Catalyst (DOC) and Selective Catalytic Reduction (SCR) technology. They also utilise an asymmetric twin-scroll turbocharger, which has two different sized scrolls, to stream exhaust gases across the turbine wheel at varying velocities, for rapid response and maximum output.
An electronic hydraulic power control system minimises fuel consumption, while increasing digging efficiency. It utilises nine sensors across the machine to calculate the required flow and pump output, delivering maximum efficiency. The HX800A L has two variable displacement tandem axial piston pumps, each delivering 504 lpm of flow, while the larger HX1000A L has three pumps producing 523 lpm each. A closed-centre main control valve ensures that there is minimal hydraulic flow in the stand-by position, reducing fuel use. In both machines, the pumps have a cross-sensing system to reduce fuel use and to ensure that dig-end hydraulics operate independently.
The excavators have four operating modes and four power modes, working in combination with Variable Speed Control and Pump Torque Control, allowing the operator to select specific engine and hydraulic system outputs to suit the task at hand.They come with a boom priority mode and a swing priority mode, that increase breakout power or slewing speed to suit the operation.
Boom regeneration and dipper arm regeneration allow hydraulic oil to flow through the main control valve as the boom is lowered, reducing fuel consumption and increasing speed of operation. The bucket cylinder is supplied by two spools in the control valve, for faster operation and reduced resistance within the system. The engine radiators and the oil coolers have hydraulically-driven cooling fans, that can be reversed to blow out dust and debris when needed.