Hydraulic Excavator Delivers Strong Performance

Back in September 2012, Rock Products visited Caterpillar’s Tinaja Hills facility in Arizona, and watched the Cat 390D L in action. The 90-metric-ton (198,000-lb.) L Hydraulic Excavator, which replaces the 385C L, incorporates a refined design that provides greater hydraulic power, stronger structural components, added safety and convenience features, plus improved serviceability, according to the company. The net result is a more productive, more durable, more efficient machine that is comfortable to operate and can take on the toughest jobs in a range of heavy-construction and mining applications.

Engine and Hydraulics
Powering the new 390D L is the 18.1-L (1,104 cu. in.) Cat C18 ACERT diesel engine. The C18 features advanced electronic control, precise fuel delivery and refined air management for optimum performance, fuel efficiency and emissions control. The torque characteristics of the engine allow full power at maximum rpm, resulting in efficient hydraulic-pump operation and positive hydraulic response. Refinements in the crankcase, cylinder heads and proprietary MEUI (Mechanical Electronic Unit Injector) fuel system provide enhanced performance and durability for the C18.

Design enhancements in the implement hydraulic system allow the 390D L to deliver significantly greater digging and lifting forces than its 385C predecessor. Main relief pressure in the implement circuits has been increased to 5,080 psi (35 000 kPa), up nearly 10 percent from that of the 385C.

This increase in operating pressure, combined with larger-diameter hydraulic cylinders, results in a 9 percent boost in digging-arm and bucket breakout forces for the general-purpose and reach front-end configurations, and a 7 percent increase for the mass excavation configuration. Increased breakout force promotes faster trenching and loading cycles, plus stronger performance at the quarry face. In addition, lifting capacity over the end is increased by 9 percent, and over-the-side capacity is up nearly 20 percent – the result of stronger hydraulics and a heavier counterweight.

Also new in the implement hydraulic circuits are electrically controlled regeneration valves, which assure rapid, positive response from the boom and digging-arm cylinders, while also significantly improving overall hydraulic efficiency. The resulting benefits include quicker cycle times and estimated fuel savings of more than 2 percent.

Cat Large Excavator Highlights

  • Cat ACERT technology works at the point of combustion to optimize engine performance and provide low exhaust emissions.
  • The optimized hydraulic system has been designed to provide reliability and outstanding controllability.
  • The operator station provides maximum space, wider visibility, and easy access to switches. All of this ensures the most comfortable working environment for the operator.
  • Many boom and stick options are available, offering a large range of configurations suitable for a wide variety of applications.
  • Cat designed excavator undercarriage is stable, durable, and low maintenance.
  • Caterpillar offers a wide variety of factory-installed auxiliary hydraulic and work tool options. This best-in-class versatility enhances performance and job site management.
  • Fast, easy service has been designed in with extended service intervals, advanced filtration, convenient filter access and user-friendly electronic diagnostics for increased productivity and reduced maintenance costs.