Caterpillar has introduced a Hybrid Excavator to their product line called the 336EH. Although it has an almost identical look to it’s non-hybrid older sibling, the new excavator sports a green bar on the display console which provides information regarding the fills and empties of the bucket.
Caterpillar has created a machine which burns significantly less diesel fuel, rumbles at a different pitch with a lower roar. It also is able to capture and re-use the energy which is ordinarily lost during the swinging action of the digging cycle.
The new machine actually captures the swinging energy and uses it during the slowed portion of the rotation to pump hydraulic fluid into it’s accumulator tank which is recharged with nitrogen gas. The hydraulic fluid is then released back out to aid the return swing, and providing more consistency in the rate that the engine runs. Lowering the pace from 1,800 rpm to 1,500 rpm – which is a more efficient rate for it’s 300-hp, Interim Tier 4, 9-liter Cat diesel engine.
This reduces the engine load, results in savings because it provides a 50% jump in fuel efficiency, and creates fewer emissions. It’s also said to be the very first use of a hydraulic hybrid system which pressurizes hydraulic fluid in accumulator tanks in the excavation industry. – Trash trucks have also utilized hydraulic hybrid systems to accommodate their stop/start use.
Currently the hybrid excavator is manufactured in Japan, and will eventually also be manufactured in Texas and Belgium (depending upon the market in Europe). All of the components – excluding the accumulator tanks – are manufactured by Caterpillar which should keep maintenance needs parallel with similar Caterpillar machinery.
This excavator is sold for $410,000 which is a 9% increase from the cost of the regular 336E model. – But it’s said to be able to pay back that amount in fuel savings after one year.
Caterpillar has plans to introduce two new hybrid machines to the market including a 336FH and a 336DH to accommodate emission standards in other countries.