Caterpillar unveils hybrid excavator, Peoria, Ill., Oct. 15-16, 2012
Editor’s note: On Oct. 15-16, 2012, Caterpillar hosted a gathering of trade press editors from around the world to learn about the
next generation of Cat® products and technologies. The event, titled “The Next Generation is Here,” introduced the trade press to the
Cat 336E H hybrid excavator and featured the 966K XE medium wheel loader with advanced powertrain, a prototype 160M3 motor grader, and the engine and aftertreatment solution that will power the motor grader and many other Cat machines while producing near zero criteria emissions — oxides of nitrogen and particulate matter — starting in 2014.
Caterpillar, Peoria, Ill., unveiled the first model in its new line of hybrid excavators, the Cat® 336E H, at its Mossville Industrial Design Center, Mossville, Ill., on Oct. 16 at a special trade press event, “The Next Generation is Here.” The 336E H will be sold and serviced exclusively through the global Cat dealer network following the machine’s official launch at Bauma 2013 in Munich, Germany. Ordering for the Cat 336E H opens in Feb. 2013, with factory shipments planned for March 2013.
The design of the 336E H uses many existing Cat hydraulic components with a new control system. The machine uses a large accumulator to store energy as pressurized hydraulic fluid as the boom swings in one direction, which is released as the boom swings in the opposite direction. Because this back-and-forth motion is common in high-production applications, this technology combined with other efficiencies in the machine can save about 25 percent fuel usage over the current non-hybrid counterpart, which will still be available for customers not wanting to pay the premium on the hybrid version — a premium that Caterpillar says can be recouped in fuel cost savings by customers in as little as one year.
The Cat 336E H does not use batteries to store electric energy, but instead uses a new hydraulic hybrid technology developed by Caterpillar. “A hybrid is independent of any particular technology — it doesn’t have to be electric,” said Ken Gray, global product manager for large hydraulic excavators for Caterpillar’s Excavation Division. “There are many ways to store and reuse energy, including our patented hydraulic hybrid system featured on the Cat 336E H.”
Caterpillar says the most challenging part of designing the machine, which has 300 new patents, is in the control system. The Cat electronic standardized programmable (ESP) pump is designed to smoothly transition between the engine and accumulator so that the new technology is transparent to the operator. The Cat adaptive control system (ACS) valve is designed to manage restrictions and flows to control machine motion with no loss of power and to ensure operators experience no difference in control, hydraulic power or lift capability.
“The 336E H is a game-changer — the most revolutionary excavator to come to market in decades,” said Gary Stampanato, vice president of Caterpillar’s Excavation Division. “Customers aren’t going to choose the 336E H simply because it is sustainable. They will select it because it actually lowers their owning and operating costs, and maintains the performance of our industry leader, the 336E.”
The 966K XE medium wheel loader with advanced powertrain also delivers up to 25 percent improved fuel efficiency by using an integrated Cat continuously variable transmission system, the company says. A hydraulic pump and motor (variator unit) is designed to allow
for a smooth and continuous gear ratio change between engine speed and machine speed. Power is transmitted through the variator unit as well as a parallel mechanical gear path. The 966K XE is powered by a Cat C9.3 ACERTTM diesel engine, delivering up to 290 hp.
The 966K XE has two pedals and is designed with reduced operating interface/mode complexity. The company says an operator can utilize the machine while the integral power system control prevents engine over-speeding and makes it nearly impossible to stall the engine while digging.
Caterpillar also discussed its approach to achieving final Tier 4 certification for its engines in the 170- to 750-hp range. By using a “view with the end in mind” strategy, the company says its final Tier 4 engines use as much as 15 percent less fluids than its Tier 4i engines, even though these engines use select catalytic reduction (SCR) systems, which require the use of diesel exhaust fluid (DEF). Because DEF is used at about 10 percent of diesel use, the company says this means these engines are as much as 25 percent more fuel efficient.