Another concern is the effect of overheating on the combustion process and
the changes in emissions levels this can
bring. Toyota, for one, has introduced an
improved cooling system with the ability
to reduce power usage automatically to
help prevent overheating and maintain
the proper emissions levels, according to
Mark Faiman, a product manager for
Toyota Material Handling, U.S.A., Inc.
(TMHU).
Typically, operators must stop the truck
and wait while accumulated particulates
burn off. That’s a productivity-buster, says
Dumdie. So some manufacturers have
found ways to carry out that process while
the truck is running, without overheating.
The Perkins-built engines in Mitsubishi’s
and Cat’s Tier 4 final trucks, for example,
heat up the DPF and automatically burn
off soot while the vehicle is in operation.
Diesel lift trucks are designed for heavy-duty applications, so manufacturers that
opt for smaller engines (which use less
fuel and therefore, produce lower emissions) can’t compromise power or lifting
capacity. Toyota addressed that by incorporating a new electronic common-rail
fuel injection system and an intercooled
turbocharger into its fuel-sipping four-cylinder engine. Thanks to these and
other design changes, the new model provides greater torque and as much horsepower as the previous inline six-cylinder
engine, says Cesar Jimenez, TMHU’s
national product planning manager.
Fuel and lubricating oil are another
consideration with Tier 4-compliant
engines. Because sulfur can severely damage catalytic converters, low-emissions
engines require ultra-low-sulfur diesel
(ULSD) fuel, Provancher says. Although
ULSD is in wide use, it may not be readily available everywhere lift truck fleets
operate, he observes.
As for engine oil, because the emissions
control systems generate more heat and
the ash residue left when lube oil burns
off during combustion can foul particulate filters, CJ- 4 lubricant is recommended for engines using DPF and EGR systems, says Webb. “CJ- 4 is more resistant to
heat and produces less ash,” he explains,
which in most cases prolongs the interval
between cleanings.
BUYERS BE AWARE
Initial purchase prices for Tier 4 final
lift trucks will be higher than those
for their Tier 3 predecessors. That’s
not surprising considering the addi-
tional costs engine and lift truck
makers have incurred over the past
decade, Provancher says. It’s too
early to say what Tier 4 final pricing
could or should be over the long
term, he continues, “but realistically,
there’s a good substitute with LPG
(liquefied petroleum gas), and the
market is only going to bear so much
when it comes to purchase price.” In
the short term, there will be oppor-
