Cummins Inc. has announced the introduction of the QSF3.8 engine with a power range extending from 85 to 132 hp (63-98 kW) ready to meet EPA Tier 4 Final and EU Stage IV near-zero emissions standards. The all-new four-cylinder, 3.8- liter platform with full-authority electronic controls and High Pressure Common Rail (HPCR) fuel system will be revealed for the first time at Bauma.
The QSF3.8 is designed as a fully integrated air-intake to exhaust aftertreatment system supplied as a drop-in installation for all types of compact construction and materials handling equipment. The QSF3.8 utilizes Cooled Exhaust Gas Recirculation (EGR) and the latest Selective Catalytic Reduction (SCR) technology from Cummins Emission Solutions, without the need for a Diesel Particulate Filter (DPF). Near-zero emissions regulations for engines in the QSF3.8 power range take effect in October 2014 for Stage IV and in January 2015 for Tier 4 Final.
With the advantage of a clean-sheet design, the QSF3.8 is able to combine the performance attributes of a compact, highly economic engine with the durability associated with Cummins larger QSB4.5 engine. Although larger in displacement and meeting more severe emissions standards, the QSF3.8 achieves fuel efficiency similar to that of the 3.3-liter engine. The 132-hp (98 kW) maximum power of the QSF3.8 exceeds that of the QSB3.3 to reach the highest output in the sub 4-liter engine class. QSF3.8 peak torque is equally impressive, at 360 lb-ft (488 Nm).
A key design focus for the QSF3.8 was to minimize operating costs, with service-free features such as a crankcase ventilation breather requiring no filter element, reducing emissions and ensuring an exceptionally clean engine.
QSB4.5 Engine Updates
Cummins also has announced the next-generation QSB4.5 engine will meet Tier 4 Final near-zero emissions standards with top-rated power increased to 173 hp (129 kW) and a higher peak torque of 520 lb-ft (705 Nm). The four-cylinder, 4.5-liter engine is performance enhanced with a Cummins VGT(TM) Variable Geometry Turbocharger, enabling the higher ratings of the QSB4.5 to reach performance levels previously associated with a larger six-cylinder engine.
For the QSB4.5 lower ratings down to 121 hp (90 kW), the VGT technology improves transient response on a fuel efficient basis. For equipment operation, this means a stronger, faster response to increasing load demands compared to Tier 4 Interim.
The QSB4.5 was a key focus of attention in the Cummins booth at World of Concrete. It was shown ready for the EPA Tier 4 Final emission regulations taking effect Jan. 1, 2015 and EU Stage IV taking effect Oct. 1, 2014 for engines below 174 hp (130 kW).
The ability to move forward to meet near-zero Tier 4 Final emissions standards has been pre-designed into the existing QSB4.5 engine platform, retaining the same cooled Exhaust Gas Recirculation (EGR) system proven with the current Tier 4 Interim engine. The Cummins Compact Catalyst (CCC) aftertreatment is also retained, with the addition of Selective Catalytic Reduction (SCR) in the exhaust stream. The combined CCC-SCR aftertreatment is designed and manufactured by Cummins Emission Solutions, with the highest level of engine and system integration expertise in the industry.
The patented Variable Geometry Turbocharger utilized on the QSB4.5 is a smaller version of the VGT proven on Cummins 6-cylinder engines. The VGT features a unique, one-piece sliding-nozzle to precisely adjust the airflow delivered to the engine. This combines the advantages of a small and large turbocharger in a single unit, so that rapid boost is provided at low engine rpm, and then high boost is maintained at higher rpm.
The QSB4.5 achieves 173 hp (129 kW) with a single turbocharger, in contrast to other 4-cylinder engines below 5-liters requiring two turbochargers to achieve equivalent power, torque and altitude capability.
To remove Particulate Matter (PM) from the exhaust, the Cummins Compact Catalyst (CCC) aftertreatment moves forward to Tier 4 Final with the same "fit and forget" advantage realized for Tier 4 Interim applications, with a smaller space claim than a Diesel Particulate Filter (DPF).
The very low Nitrogen Oxide (NOx) emissions levels required for Tier 4 Final are achieved by incorporating Cummins Selective Catalytic Reduction (SCR) aftertreatment in the exhaust stream, configured for compact 4- cylinder applications. The SCR uses a catalyst specified to deliver a robust solution, able to operate more efficiently at lower temperatures and features advanced sensors to provide full closed-loop control. Diesel Exhaust Fluid (DEF) dosing levels are minimized due to an enhanced mixing technique.
The CCC-SCR aftertreatment is available in multiple configurations including switchback, horizontal and vertical formats to provide an easier and more flexible installation.
For Tier 4 Final, the QSB4.5 builds on the class-leading durability and uptime dependability established by the Tier 3 engine and continued by the current Tier 4 Interim engine. Deep structural strength equips the engine to handle high load factors with relaxed operation, while features such as a rear gear train provide superior stiffness and lower gear noise.
The High Pressure Common Rail (HPCR) fuel system and Electronic Control Module (ECM) of the 4-cylinder QSB4.5 are of the same design and offer robustness equal to that of the fuel system and ECM utilized on the 6- cylinder QSB6.7, capable of up to 300 hp (224 kW).
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