Las Vegas (September 22, 2008) - Cummins Inc. (NYSE: CMI) product lineup at the MINExpo show features the QSK19, QSK38, QSK50 and QSK60 engines to highlight class-leading, fuel-efficient power for mining haul trucks and excavators. Meeting EPA Tier 2 emissions across a broad 760 to 2700-hp (567-2013 kW) power band, the19- to 60-liter QSK Series incorporates Cummins Modular Common Rail fuel system to enable cleaner combustion with fuel efficiency optimized for high engine loads.
Mining haul trucks, excavators and wheel loaders all have significantly different duty cycles related to application. Cummins expertise is applied to achieve the lowest overall fuel consumption by precisely matching engine power, torque and low emissions requirements to meet the most demanding load factors of the equipment.
“The multiple fuel injection flexibility provided by Cummins Modular Common Rail System driven by advanced electronic controls is a significant performance enabler to achieve the best fuel efficiency match between engine and equipment,” commented Jim Trueblood, Cummins Vice-President, High-Horsepower Engineering.
“Our application engineers are committed to developing a tailored engine calibration for each specific piece of equipment and application. This means the engine delivers the necessary power, torque and transient response with fuel efficiency optimized for high engine loads when the equipment is working hardest and consuming most of the daily bulk of fuel. We also factor in environmental influences such as operating altitude and and ambient conditions to further fine tune the fuel efficiency of the calibration.
“As a result, Cummins Tier 2 engines run cleaner with low emissions while achieving the lowest overall fuel consumption over the course of a tough duty cycle. This is in contrast to some competitors who have focused their efforts on optimizing fuel consumption at idle or low-load operation,” added Trueblood.
While achieving fuel efficiency is an important factor in achieving lowest cost-per-ton for mining equipment, other factors such as engine reliability, durability and uptime availability make equally important contributions.
This is an area where Cummins scores highly, with QSK engines increasingly specified for excavators operating with the highest engine load factors of any mining equipment. This capability to achieve lowest-cost-per-ton in high duty cycle applications is reflected in Cummins powering around 85 percent of all mining excavators.
MCRS Performance With Safety
Cummins Modular Common Rail System (MCRS) is employed on all Tier 2-compliant engines and has a scalable, modular architecture sized to the individual engine platform. The fuel system brings performance benefits such as 50 percent improved idle stability and cold-start characteristics, together with faster load acceptance. Engine sociability is enhanced by the system eliminating unbalanced fueling across cylinders, offering much reduced vibration and up to 80 percent lower noise at rated power.
Cummins takes a proactive approach to ensure engine safety with a leak-prevention design approach. MCRS offers the advantage of a sealed fuel system with high-strength double-wall fuel pipes. In the unlikely event of a leak from the inner wall, the fuel would then be contained with the second safety wall.
A further MCRS safety advantage is that an accumulator is integral to each injector, enabling serial connection to the fuel pump. This avoids the need for a longer, more exposed fuel rail with inherently less durability.
Leak-resistant techniques also extend to oil lines with stainless steel braided hoses together with advanced materials used for gaskets. Coolant lines and filter connections are similarly designed for maximum integrity.
Cummins clean combustion technology not only delivers improved fuel efficiency but enhances life-to-overhaul by maintaining piston speed and cylinder pressure at lower levels than competitive engines. Specially strengthened Ferrous Cast Ductile (FCD) iron pistons are common to all Cummins QSK Tier 2 engines to further reinforce engine durability. The FCD piston allows even expansion and contraction during thermal cycles while cooling nozzles provide a high rate of oil flow rate to the piston.
While life-to-overhaul can be expressed in hours, Cummins prefers to focus on average design life-to-overhaul in terms of gallons of fuel consumed as a more accurate measure which better reflects high engine load operating factors. Depending upon duty cycle, the average design life-to-overhaul for the QSK60 exceeds 1,000,000 U.S. gallons (3,785,000 liters) of fuel consumed and for the QSK50 this is 875,000 gallons (3,312,000 liters). For the QSK38 the average is 625,000 gallons (2,366,000 liters) of fuel consumed and for the QSK19 this is 300,000 gallons (1,136,000 liters).
These impressive figures are believed to be unmatched in the mining industry by other comparable engines. Significantly, Cummins QSK engines are designed for ease of rebuilding at overhaul to enable multiple working lives and lower the total overall cost of ownership.
Cummins Inc., a global power leader, is a corporation of complementary business units that design, manufacture, distribute and service engines and related technologies, including fuel systems, controls, air handling, filtration, emission solutions and electrical power generation systems. Headquartered in Columbus, Indiana (USA), Cummins serves customers in approximately 190 countries and territories through a network of more than 500 company-owned and independent distributor locations and approximately 5,200 dealer locations. Cummins reported net income of $739 million on sales of $13.05 billion in 2007.