Cummins QSK High-Horsepower Engines for the Oil and Gas Industry to Meet Tier 4 Final with Integrated SCR Aftertreatment

Cummins Inc. (NYSE: CMI) announced today that the QSK Series of 19-liter to 60-liter engines for oil and gas applications will move forward to meet the EPA Tier 4 Final 2015 off-highway emissions with a combination of clean in-cylinder combustion and integrated Selective Catalytic Reduction (SCR) aftertreatment.

The QSK high-horsepower engines with the new SCR clean exhaust system achieve very low emissions while retaining the exceptional power output and in-service dependability of the current QSK engines – proven in the highest load factor duty cycles. Cummins clean in-cylinder combustion for Tier 4 Final realizes significantly lower overall cost of operation, with fuel efficiency improved by 5 percent to 10 percent, depending on the equipment duty cycle.

For most oil and gas applications, the Tier 4 Final QSK engine and integrated SCR aftertreatment system offer the installation simplicity of a drop-in replacement for the current QSK engine and exhaust muffler, with a similar size and equivalent noise reduction.

The SCR clean exhaust system has been revealed at the opening of the Cummins Oil and Gas Center of Excellence located in Houston. The center has been established to design and assemble complete power packages for specific customer requirements. The facility will take a lead role in introducing Tier 4 Final power packages for frac rigs, drilling modules, mud pumps and well servicing pumps.

"Cummins QSK engines are used in the most demanding oil and gas applications, so it is important that we have achieved Tier 4 Final emissions with no compromise to performance or reliability,” said Erik Drewry, Director – Cummins High-Horsepower Oil and Gas Business.

"Our next-generation QSK engines with integrated SCR aftertreatment are designed as a drop-in replacement for simpler machine installation and assembly. Designed and manufactured by Cummins Emission Solutions, the SCR clean exhaust system further demonstrates the added value of our single source, integration capability.

"Power output, durability and ease of service will remain the same at Tier 4 Final as those of our current industry-leading QSK engines. Cummins solution also offers the simplest and most effective approach to lower the cost of operation for oil and gas equipment operators, while meeting very low emissions levels.

"We have delivered on our promise to the oil and gas industry to make the technology transition to Tier 4 Final as seamlessly as possible,” added Drewry.

Cummins experience of SCR aftertreatment is unrivalled in the industry, dating back to 2006 with European on-highway emissions. Today Cummins has almost 100,000 EPA 2010 on-highway engines operating with SCR in North America. Cummins SCR systems have proven remarkably robust in-service, with equivalent durability to that of the engine.

This unrivalled level of SCR expertise has been fully leveraged by Cummins to develop the new SCR clean exhaust system for QSK high-horsepower applications in the oil and gas industry, extending from 800 hp to 3000 hp (597-2237 kW).

The packaging of the SCR catalyst is specially strengthened for the harshest operating conditions in the off-highway industry, featuring enhanced protection against vibration and shock loadings.

Lower Emissions With Simpler Technology

Cummins SCR clean exhaust system reduces oxides of nitrogen (NOx) emissions to 3.5 g/kW-hr for Tier 4 Final off-highway, representing a more than 40 percent reduction compared with the Tier 2 level.

By focusing NOx reduction within the exhaust rather than during in-cylinder combustion, Cummins avoids the need to make any major change to the external engine platform. Using SCR also leaves a much higher performance threshold in-cylinder in order to focus on Particulate Matter (PM) reduction and improve fuel-efficiency.

PM emissions are reduced by 80 percent to meet the 0.04 g/kW-hr level for Tier 4 Final. This is achieved by a clean-combustion formula utilizing higher-pressure fuel injection and enhancements to the power cylinder design. This inherent capability to achieve higher injection pressure is a key feature carried forward from the fuel system on today’s QSK engine range. Highly efficient PM reduction in-cylinder eliminates the need for either a diesel oxidation catalyst or diesel particulate filter aftertreatment in the exhaust stream.

Reducing The Cost Of Operation

The fuel savings achieved by Cummins Tier 4 Final clean in-cylinder combustion will more than offset the cost of Diesel Exhaust Fluid (DEF) dosing required for the functioning of the SCR aftertreatment.

Depending on duty cycle and application, Cummins clean combustion for Tier 4 Final enables fuel efficiency to be improved by 5 percent to 10 percent compared with Tier 2 engines, with DEF consumption to fuel held as low as 2 percent to 3 percent.

For many applications, this results in a major reduction in overall operating costs, taking into account the cost of both diesel fuel and DEF. With the cost of bulk DEF lower than that of diesel fuel and anticipated to fall further as the off-highway market supply expands over the next few years, this brings an added cost advantage to using SCR aftertreatment.

As a further advantage for operators, there are no additional service requirements for the QSK Tier 4 Final engine compared with the Tier 2 engine. With only minimal external changes to the engine, this means that ease of serviceability remains the same.

SCR Clean Exhaust System

The new SCR clean exhaust system is a highly robust, fully integrated aftertreatment package specifically developed by Cummins Emission Solutions for high-horsepower applications. The SCR aftertreatment operates as a fully passive, flow-through system and is capable of high NOx conversion with low backpressure, enabling enhanced fuel economy.

Cummins SCR clean exhaust system utilizes an innovative DEF decomposition process to significantly reduce space claim and benefit overall equipment integration while ensuring that low NOx emissions levels are achieved. The SCR system also features an integral DEF dosing injector with a high-efficiency spray pattern.

SCR logic control is driven by the QSK electronic engine management system, upgraded with extra processing power for Tier 4 Final so that the engine and SCR aftertreatment operate as a single, integrated system.

The SCR modular configuration is scalable for the complete QSK engine line-up to ease integration and assembly by the equipment manufacturer. For applications below 1500 hp (1119 kW), a single-catalyst SCR system is used in varying lengths sized to engine output. A twin-catalyst SCR system is used for applications above 1500 hp, each aligned with a cylinder bank and matched to engine power output. For most applications, the SCR system replaces the current muffler within an equivalent size envelope and provides similar sound suppression.

Using Diesel Exhaust Fluid

Diesel Exhaust Fluid is the reactant necessary for the SCR system to function. DEF is a product certified by the American Petroleum Institute (API), consisting of an aqueous solution of 32.5 percent high-purity urea and 67.5 percent deionized water, and requires no special handling.

A series of advanced sensors monitor the Cummins SCR clean exhaust system operation to match DEF dosing levels to engine load and duty cycle for more efficient consumption.

"With low levels of DEF consumption, on-board DEF tanks can be easily sized to meet the fuel tank capacity of the most powerful frac rigs – ones with 3000 hp (2237 kW) output,” said Jason Mao, Cummins Oil and Gas Application Leader.

"The DEF tank can also be increased in size for applications requiring extended refilling intervals. This tank-sizing flexibility is something we can easily align with the specific operational requirements of the equipment,” added Mao.

Today, Cummins Filtration supplies Air Shield™ DEF to the Cummins distribution network to support on-highway truck operators using EPA 2010-compliant engines. Cummins and other DEF suppliers will have a nationwide service readily available for off-highway equipment users when required for the Tier 4 Final introduction. A wide range of DEF packaging size options are available, extending up to 330-gallon reusable totes and bulk delivery. Cummins can help equipment operators calculate DEF usage and plan the most cost-effective choice to lower their cost of operation.

Cummins SCR Experience

The SCR clean exhaust system integrated with the Tier 4 Final QSK engines is designed and manufactured by Cummins Emission Solutions, one of the world’s largest suppliers of exhaust aftertreatment, with 350,000 SCR systems produced. This in-house capability is unique in the industry and ensures the highest level of system integration between engine and aftertreatment.

"Our ability to leverage preceding SCR experience and then optimize it for high-horsepower applications with the new SCR clean exhaust system enables Cummins to deliver the right emissions solution for Tier 4 Final,” said Julie Furber, General Manager – Off-Highway Business, Cummins Emission Solutions.

"We have been able to develop an innovative SCR packaging configuration with modular flexibility to replace the exhaust muffler within virtually the same space envelope – a first in the aftertreatment industry for high-horsepower applications,” added Furber.

About Cummins Inc.

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 employs approximately 40,000 people worldwide and serves customers in approximately 190 countries and territories through a network of more than 600 company-owned and independent distributor locations and approximately 6,000 dealer locations. Cummins earned $1.0 billion on sales of $13.2 billion in 2010.

Press releases can be found on the Web at cummins.com or cumminsengines.com. Follow Cummins on Twitter at http://twitter.com/cumminsengines and YouTube at http://youtube.com/cumminsengines.

Note to editor:
The following photographs can be downloaded at http://cumminsengines.com/press:
- Cummins Tier 4 Final QSK50 engine with 2500 hp (1864 kW) output for frac rigs
- Single-catalyst version of the Cummins SCR clean exhaust system for the Tier 4 Final QSK engines, replacing the muffler