Sources: Hyster Co., Greenville, N.C.; CP staff
Hyster engineers’ disassembly and in-depth examination of a Tier 4 Cummins QSL9 engine—powering one of the manufacturer’s Big Trucks series forklifts for nearly 10,000 hours—revealed major components, fuel system, turbocharger and block to be in near-perfect condition after three years in a heavy duty application. The results suggest a Cummins Inc. Tier 4 package could complete 20,000 hours of operation before an engine overhaul may be needed, which is equal to the life-to-rebuild of the larger 11-liter QSM11 Tier 3 engine in a similar duty cycle.
“This test proves Tier 4 engines combine all of the performance, durability and toughness associated with [our] lift trucks, with significantly enhanced fuel economy and sustainability benefits to achieve compliance and help increase profitability,” contends Hyster Big Trucks President Brett Schemerhorn.
Hyster and Cummins have led the industry charge in developing smarter, right-sized engines, he adds. With smaller displacement than predecessor Big Trucks-suited models, Tier 4 engines produce similar or greater horsepower and torque while consuming less fuel and generating fewer emissions through an integrated design. Among additional features driving QSL9-powered lift truck fuel economy:
- On-demand cooling to help reduce fuel consumption and noise;
- On-demand load-sensing hydraulics to help reduce fuel use and increase hydraulic system component life;
- Empty seat engine shutdown to reduce non-productive idling;
- Idle management to reduce engine rpms when truck is not in active operation;
- Automatic throttle-up to enable the engine to work in its “sweet spot”; and,
- Selectable “ECO” drive modes to balance power requirements and fuel consumption.
Prior to the teardown, Cummins tested the QSL9 on power delivery and fuel consumption, as well as emissions and torque to ensure a) the engine remained within acceptable tolerance levels, and b) that only normal service was needed. An added benefit over Tier 3 models is that Tier 4 successors do not require any specific mid-life service intervention.
“Cummins design philosophy is to utilize only proven technologies and components that we know will meet the in-service reliability and long-term durability demanded for the toughest equipment applications—and the advantage of taking this approach is reflected in the results of the QSL9 Tier 4 teardown inspection,” affirms Off-Highway Business Executive Director Hugh Foden.