Photo by Jeff Rubenstone for ENR

The 336EH has the same profile as the non-hybrid model but boasts superior fuel consumption.

As a slowdown in mining sales softens its bottom line, equipment giant Caterpillar Inc. is hoping construction customers will be drawn to the promised fuel savings in its new 336EH hybrid excavator.

Earlier this month, ENR visited the company's demonstration center in Edwards, Ill., to see the machine up close. Announced last year, the new machine is based on the design of the existing non-hybrid 336E but uses a special hydraulic hybrid system to recycle energy.

The system takes advantage of an excavator's typical duty cycle: digging, swinging, dumping and swinging back to dig. The excavator captures swing energy as the machine's rotation slows down by storing pressurized fluid in accumulator tanks. It then pushes the fluid back out to aid the next cycle.

According to Caterpillar, the new 40-ton model boasts a 25% fuel consumption improvement over the non-hybrid 336E, with only a 9% price increase. But when measured in tons moved per liter of fuel, the machine promises up to a 50% fuel-efficiency increase.

Running on the same 300-hp, Tier 4 Interim Cat 9-liter diesel engine as the standard 336E excavator, the hybrid model adds a pair of hydraulic accumulator tanks, located in the back of the machine and precharged with nitrogen gas. The stored hydraulic power allows the excavator’s diesel engine to run at a near-constant speed of 1,500 rpm, which conserves fuel and emissions.

Caterpillar says order sheets for the new hybrid are full, but the company is keeping mum about the size of the initial run. The 336EH will be formally launched at Bauma later this month in Munich, where Caterpillar will hand the keys of the machine to its first buyer, Norway-based SA-Anlegg AS.

"The hybrid is currently being manufactured in our facility in Japan, and we plan to build them in our Victoria, Texas, facility for the American market," says Ken Gray, Caterpillar global product manager for large hydraulic excavators. "If there's a good reception at Bauma, it will then be built in our Belgian plant.”

The non-hybrid 336E will continue to be available, Gray adds. “We want the customer to have that option, but we see the hydraulic hybrid as a complete system, not just an add-on [to the 336E],” he says. Caterpillar is also developing a 336FH excavator, which will meet Tier 4 Final emissions standards.

Caterpillar may be looking for a bright spot in the construction sector as the equipment giant has taken a hit in its mining division this year. The company took a $580-million write-down at the beginning of the year after its acquisition of a China-based mining equipment manufacturer went sour. The write-down, coupled with an overall softening mining sector, has resulted in lower demand for the company's new mining equipment.

These recent issues may be to blame for recent layoffs at several of Caterpillar’s U.S. facilities, including over 460 positions at its Decatur, Ill., plant and up to 300 positions in its South Milwaukee, Wis., facility, both set to take effect in June.

Analysts have lowered their expectations for Caterpillar’s first-quarter earnings, as the company is expected to report its first back-to-back drop in quarterly profit since 2009.