Long service life under tough conditions
With temperatures fluctuating from zero to 105 degrees Fahrenheit, the typical life expectancy of an engine operating within one of the groundshaking haul trucks at Logan is approximately 20,000 hours. The Series 4000 Tier 2 engine from MTU, however, is something else. Installed in a Komatsu 830 haul truck, it has been running 50,000 hours – equivalent to 20 hours per day and 6,000 hours per year – carrying loads weighing up to 240 tons and twice-enduring “conditions that are extreme,” as Benny Dixon, responsible for haul truck maintenance at the Patriot Coal Mine, reports.
Engine perfectly tuned to application
How did this remarkable engine last so long after the truck was repowered with the MTU engine? According to Dixon, the root of this success lies in MTU’s expert engineering and the tailored service plans and expert repower recommended by its distributor and maintenance partner, Western Branch Diesel. Traditionally, a 16-cylinder engine powers the Komatsu 830. However, because a large part of this particular haul truck’s role at Apogee is downhill hauling – often without a load – it was greatly overpowered, according to Curtis Bartlett, Off-Highway Sales Engineer at Western Branch Diesel.
To maximize efficiency, Bartlett and the team at Western Branch Diesel recommended reducing the existing 16-cylinder engine to a 12-cylinder MTU Series 4000 engine to decrease horsepower from 2,200 to 1,875. Ultimately, this strategic move reduced fuel burn by five to seven percent and helped double the life span of the engine. “The name of the game is to customize as much as possible,” said Bartlett. “That’s how we’ve been able to extend life cycle intervals on thesecomponents.” Repowering Komatsu 830s with MTU engines is not a rare occurrence. It’s a task that could take approximately four days, and at a mine site where there is no workshop or electricity, the process is both an art and a science. More than 750 of all Komatsu haul trucks in use today have been repowered with MTU engines, according Randy Murphy, Senior Sales Manager, Global Mining Sales at MTU. For Patriot Coal, these calculated repowers have been instrumental in maximizing fuel efficiency and exceeding life expectancies, demonstrated by the four other MTU powered Komatsu haul trucks in operation at Patriot Coal sites with more than 40,000 hours each before any engine overhaul
“One thing I’ve noticed through the years is that if the distributor and mine maintenance team work closely together and stick close to schedule, then they exceed what we publish as a recommended time to overhaul,” said Randy Murphy, Senior Sales Manager, Global Mining Sales at MTU.