Komatsu America Corp., Rolling Meadows, Ill., recently rolled out its PC290LC-10 excavator. Powered by a 196-hp (147 kW) diesel engine, it has several design improvements to the hydraulic system that boost fuel efficiency, thereby making the entire machine more energy efficient.
Doug Morris, product manager, excavators, points out, “One of the key enhancements to the PC290LC-10 hydraulic system is a new larger displacement hydraulic pump design. Increasing the displacement of the pump makes it capable of providing a higher flow output at a lower engine speed when compared to the previous PC270LC-8. This allows the engine to operate at the most efficient speed and provides better pickup and response to the operator’s demands.”
Hydraulics ties in
The excavator uses a closed-center load-sensing hydraulics system with variable speed matching, which adjusts engine speed to match the hydraulic load. Morris continues, “Variable speed matching is a new engine and hydraulic pump control technology that we have implemented on our Tier 4 excavators. The basic idea is that on a typical excavator the engine runs at a high speed whether the pumps are delivering a large or small amount of oil. On the Tier 4 excavators, the machine monitors oil delivery, and in applications where the delivery is small, the machine adjusts the engine speed to a lower level to save energy and reduce fuel consumption.”
The PC270LC-10 4 has additional subtle improvements to the hydraulic system to increase efficiency. Morris explains, “We have made changes throughout the hydraulic system, such as to the main control valve, and we increased the diameter of some of the piping to reduce loss in the system. Another feature is the arm quick return valve. When the operator goes to dump material from the bucket using the arm out function, the quick-return valve reroutes a portion of the oil that would otherwise go back to the main valve. Sending the oil back to tank by bypassing the main control valve reduces loss and speeds up the dump speed, which ultimately improves fuel consumption and productivity.”
And, of course, the excavator incorporates Komatsu’s Equipment Energy Management System, which continuously monitors hydraulic and other critical systems to assist preventive maintenance and troubleshooting.