Komatsu PC200-8 Hybrid hydraulic excavator combines a capacitor and a diesel engine. While construction machines normally use hydraulic motors to turn their upper structures, Komatsu’s new Hybrid model uses an electric motor for that movement. The electric motor collects energy generated when the upper structure of the excavator slows down while turning. The energy collected is converted into electric energy to be stored in the capacitor. The stored electricity is utilized via a dynamo-electric motor to assist the engine when it is accelerating. As a outcome, the engine can be used in

a low-rotation zone with high-efficiency combustion. In addition, the rotation can be maintained at 700rpm when the engine runs idle (during deceleration), thereby reducing the fuel consumption.

The Komatsu PC200-8 Hybrid displays a bar graph, which indicates the amount of fuel consumed by the past five minutes, in the center of the monitor. By switching the screens, the operator can check the fuel consumption notes for the past one hour, 12 hours, one week or one month. The operator can plus monitor the charging/discharging process by the capacitor, or how the dynamo-electric motor assists the engine.