Cat's new hydraulic excavator offers fuel-saving features

  • 05-Sep-2011 10:11 EDT

The new Cat 349E hydraulic excavator features a 396 net hp (291 kW) Cat C13 ACERT engine that meets U.S. EPA Tier 4 Interim emissions standards.

Caterpillar says its new 349E hydraulic excavator, powered by a 396 net hp (291 kW) C13 ACERT diesel, delivers more engine and hydraulic power than its 345D predecessor, while consistently averaging 5% improved fuel efficiency in typical applications.

The 349E's C13 engine, which operates either on ultra-low-sulfur diesel fuel (ULSE) or a blend of ULSD and 20% biodiesel (meeting ASTM 6751 or EN 14214), uses the Cat Clean Emissions Module (CEM) to meet Tier 4 Interim standards. The CEM regeneration system is designed to be transparent to the operator and regenerate when the conditions are optimal. In automatic mode, the regeneration system allows the machine to work as normal with no interruptions to the work cycle. The system automatically senses when to regenerate during idle and while the machine is working to maintain high production. The system's manual mode allows the operator to override the automatic setting.

Among the 349E's fuel-saving features is the Engine Idle Shutdown Setting, which allows selecting how long the machine is permitted to idle before shutting down. Working with this system is an idle control feature that reduces engine speed to low idle with the touch of a button; a second touch or joystick movement puts the engine back into high speed, allowing the machine to go right back to work. Isochronous speed control—a system that maintains constant engine speed, regardless of load—further conserves fuel, as does the 349E's "economy" power mode when used during less-demanding applications.

An electric boom regeneration valve captures and recycles hydraulic energy when the boom lowers. In like manner, a new regeneration valve in the digging-arm circuit recycles oil between the cylinder ends during low-load, arm-in operation, reducing the volume of oil the hydraulic pump must produce and thus conserving fuel.

What Cat refers to as "the heart of the 349E's design" is its implement hydraulic system—the working force of the machine. A boost in hydraulic flow contributes to the new model's added power and gives it a decided advantage over its predecessor. In addition, a redesigned main control valve simplifies auxiliary line configuration for enhanced reliability.

A heavy lift mode increases the 349E's main hydraulic pressure to 5512 psi (380 bar)—a 9% increase—while also reducing engine speed and pump flow for finer control when lifting. Also, a new swing priority system now uses an electric valve, which, compared with a hydraulic valve, allows more finely tuned control.

Cab features include a new LCD monitor that is 40% larger, has higher resolution, and an improved keyboard interface. The new monitor also serves as a display for the optional rearview camera system, which can display two camera images simultaneously.

New seat choices include heated and air-cooled options; the climate control system features new outlets with positive filtration. Full adjustment of the operating consoles and the addition of an auxiliary audio port for MP3 players are also part of the operator's environment.

The optional Cat Grade Control system for depth and slope uses internal front linkage sensors to provide real-time bucket tip position, resulting in less grade checking, fewer cycles to attain grade, and reduced fuel consumption. The system can be expanded to full 3-D capability by adding Cat AccuGrade technology.

A new ROPS (roll-over protective structure) is mounted to specially designed supports in the 349's upper frame. The lower frame also has been reinforced to increase component durability. Undercarriages are available in either fixed- or variable-gauge configuration to fit the application, and an available counterweight removal device reduces preparation time for transport.

A selection of booms and digging arms are available for the 349E. Each boom and digging arm uses castings and forgings in high-stress areas. Buckets feature new geometry with the leading edge pushed forward, resulting in more efficient filling, higher production, and greater operator control. Buckets also feature improved wear resistance for corners and side cutters.

Access to routine maintenance items is improved with wider service doors (with redesigned hinges and latches) and a new two-piece hood. The water separator, with a water level sensor, includes the primary filter and is located in the side compartment at ground level. An electric priming pump is mounted on the primary filter base for easy access, and a new remote drain for the fuel tank is located in the side compartment.

Relocating the oil check gauge and the engine oil filter further speeds routine service, and a new oil drain minimizes accidental spills. In addition, optional Fast-Fill and Quick Evac systems are available for engine oil and hydraulic oil.

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