Cummins Heavy-Duty QSG12 Engine
Cummins new QSG12 is a 6-cylinder, 12-liter engine designed to meet Tier 4 Final near-zero emissions regulations with a more compact envelope and more than 30% higher power-to-weight ratio than the class average for similar engines.
Higher-efficiency air handling and advanced combustion enable the QSG12 to return to the simplicity of a wastegated turbocharger and achieve near-zero emissions without the need for a cooled exhaust gas recirculation (EGR) system. As a result, internal loads on the engine are reduced to free up extra power potential, while heat rejection is lowered by more than 40% compared with engines using cooled EGR.
With ratings covering a broad 335 to 512 hp. range, the QSG12 offers a power solution for a wide variety of demanding ag applications.
A key design focus for the QSG12 has been to achieve significant weight savings in order to increase the power-to-weight ratio. A sculptured block retains high rigidity while removing unnecessary mass. The use of composite material for the oil pan and valve cover provides further weight savings. With this innovative approach, the QSG12 achieves a low engine weight of 1,900 pounds to enable a power-to-weight ratio of .27 hp. per pound.
“The new QSG12 provides an opportunity for agricultural equipment manufacturers to downsize to a more productive and economic 12-liter engine with all the heavy-duty durability and performance they need,” says Nishant Prabhu, Cummins.
Xtra-High Pressure Advantage
The QSG12 incorporates Cummins Xtra-High Pressure Injection (XPI) fuel system, derived from the larger and more powerful QSX15 Tier 4 Final engine. Although scaled down in size for the 12-liter platform, the XPI fuel system retains all the robust, heavy-duty characteristics of the system.
With multiple injection events driven by high-precision Cummins electronic controls, the XPI fuel system contributes to a peak torque of 1700 pound-foot, together with a torque rise as high as 60% available. These attributes enable the new engine to deliver fast response to increasing load factors from low engine rpm, allowing for favorable lugging ability.
The QSG12 is designed as a fully integrated air intake-to-exhaust aftertreatment package, ready for drop-in machine integration. Designed and manufactured for this 12-liter engine, the aftertreatment combines a diesel particulate filter (DPF) with selective catalytic reduction (SCR) to achieve an ultra-clean exhaust.
The DPF operates as a near-passive device, with automatic active regeneration occurring less than 1% of engine running time. The use of a DPF in the exhaust stream provides the QSG12 with an additional margin of particulate matter emissions control at higher engine loads, to realize better transient response. The heavy-duty DPF has no impact on equipment operation, with the machine continuing to work as normal during automatic active regeneration.