Equipment World Digital Magazine
Issue link: https://read.dmtmag.com/i/320559
EquipmentWorld.com | June 2014 25 maintenance | by Tom Jackson | TJackson@randallreilly.com The war on wasted energy Diesel-electric and hybrid machines are bringing big benefi ts in the fi eld F or the past decade the drive to reduce diesel exhaust emissions has dominated the head- lines. But with the last EPA mandated deadline of 2014 for Tier 4 Final engines here, the war is over and a new front has opened in the drive for cleaner, greener equipment. The new technology trend for heavy equipment is the merger of diesel engines with electric drive trains. Unlike exhaust emissions technology, which currently stops with Tier 4 Final, the diesel-electric revolution is just getting started. MORE WORK, SMALLER ENGINES What all these diesel-electric and hybrid drive systems have in common is they allow you to run with a slightly smaller engine at a lower rpm. This translates into fuel savings, fewer PMs and longer engine life. But that's just the beginning. Electric drive systems have an infi nitely variable power band. Lug- ging the engine and redlining the tach become things of the past. Some proponents of diesel-electric earthmoving equipment are also promising that, with all the surplus electric power being generated, they may be able to do away with alternators and electrify the com- ponents that normally hang off the serpentine belt such as lube, AC and water pumps, thereby greatly reducing parasitic loads. Cummins offi cials even hinted that it might be possible one day to drive hydraulic implements with hybrid electric- ity instead of fl ywheel powered hydraulic fl uid. Manufacturers at this year's Con- Expo-Con/Agg showcased a num- ber of diesel electric and diesel-hy- brid prototypes, but also on display were a handful of machines that have already proven their worth in the dirt. These include Cat's D7E electric drive dozer, Komatsu's HB215LC-1 hybrid excavator and John Deere's 644K electric hybrid wheel loader. The Cat D7E is an electric drive dozer, not a hybrid, since it doesn't recapture energy from other systems. Rather it uses a Cat C9.3 diesel engine to convert mechanical energy into AC electrical current, which powers the fi nal drives and generates DC current for the acces- sory systems. Thanks to the electric drive motor there is no transmis- sion or gears in the driveline and the power output and speed are infi nitely variable. Alan Quinby, superintendent, Durango Services, Woodword, Oklahoma, took delivery of his fi rst Cat D7E dozer three years ago and has added three more to the fl eet. Fuel economy was the company's primary motivation, Quinby says. "We felt like the fuel savings and the increased production on that particular tractor would probably pay a big share of the labor, maybe even all of the labor Cat D7E