Fuel savings and performance gains with Cat's new excavators

Caterpillar has unveiled a new range of excavators that offer significant fuel efficiency and productivity gains compared to previous models. The new models unveiled at ConExpo-Con/Agg 2011 include the 16 tonne 316E, 20 tonne 320E 36 tonne 336E - previewed at last year's Bauma exhibition - and the 70 tonne 374D. The 90 tonne 390D is also available.

"This is one of the most comprehensive excavator launches for Europe and North America in Caterpillar's history," said Caterpillar hydraulic excavator product and application specialist Kent Pellegrini.

The new machines offer up to 6% better fuel economy than the models they replace.

According to Mr Pellegrini, these improvements are not just a function of the more efficient Tier 4 Interim/Stage IIIB engine but also refinements to the hydraulic system. A +5% increase in hydraulic pressure has been achieved with a new valve block, which has improved passages for the oil, driving both productivity - in the form of higher lifting capacities - and fuel savings.

In addition an electric regeneration valve on the boom cylinder has yielded further gains by capturing energy when the boom is lowered. A further fuel-saving feature is a button in the cab that allows the operator to drop the engine speed to idle in periods of low activity.

Compliance with the latest Stage IIIB/Interim Tier 4 emissions requirements has been achieved in part with a new after treatment module in the exhaust system, which traps and disposes of particulate matter (PM), which previously escaped as black soot. One component of this is a diesel particulate filter (DPF) which contains the PM and burns it off in a process called regeneration.

Normally the operator would not be aware of the regeneration process, as it happens as part of the normal working cycle. However, there is an option to manually regenerate the filter. This push-button system in the cab has been included for applications where on-going regeneration might pose a safety risk - if the excavator were working around flammable materials for example.

In such cases an in-cab display keeps the operator appraised of how full the DPF is getting, expressed as a percentage. When the DPF gets full, the operator can take the excavator to a safe location and manually regenerate the filter.