Diesel suppliers are preparing their engine platforms for the next set of emissions standards
By Russell A. Carter, Managing Editor
The recent bauma trade fair in Germany provided a golden opportunity for diesel engine manufacturers to introduce new models and highlight product-line upgrades for an audience of show attendees estimated at just under 600,000. Among the names most familiar to mining-industry customers, MTU, Cummins, Volvo Penta, and Caterpillar all had new engines and/or services on display, and Liebherr highlighted its new diesel/gas engine platform, which has been in development for several years.
The BelAZ 75710—billed as the world’s largest haul truck—employs two MTU Series 4000 16-cylinder diesel engines, generating a total of 3,430 kW (4,600 hp). To save fuel, both engines operate at full power only when the 450-mt-capacity truck is loaded; when empty, it runs on one engine while the other engine idles.
MTU: No Aftertreatment
MTU had a 10-cylinder Series 1600 engine and a 12-cylinder Series 2000 engine on display at bauma, covering a power range of 500-plus kW to 1,000 kW (670–1,350 hp). MTU’s Series 1600 engines are available for the 567- to 736-kW power range. In addition to complying with U.S Environmental Protection Agency’s (EPA) Tier 4 emission regulations, they also meet future European Union (EU) Stage V regulations using only internal engine technology—no exhaust aftertreatment required. MTU’s Series 2000 engines cover a power range from 560 to 1,000 kW and are compliant with EPA Tier 4 emission regulations—again, using only internal engine technology. In addition, MTU offers 8-, 12-, 16- and 20-cylinder Series 4000 models with power outputs extending to 3,000 kW. They meet EPA Tier 4 emission regulations with no exhaust gas aftertreatment.
Chief Engineer Norbert Eisenblätter, who has been with MTU for 35 years and heads its mining engine development program, recounted for E&MJ his company’s emergence as a leading engine supplier to the mining industry. “Back in the late 1980s, we were mostly unknown in the industry,” said Eisenblätter. “But after Wiseda and others began to develop the first two-axle, 240-ton trucks, they asked us if we could provide a four-stroke, 2,500-hp engine—the big trucks at the time were often powered by a Detroit Diesel 149 Series two-stroke diesel.”
“We said ‘of course,’ and that marked the beginning of our involvement in the mining industry,” he explained. “Later, in the 1990s when the industry went to 320-ton trucks, we developed a 3,700-hp engine. And as part of our collaboration with Detroit Diesel, we developed the 4000 series engines, which had a common-rail fuel injection system. Mining customers saw the advantage of this unique feature—reduced fuel consumption with overall lower cost of ownership—and that opened a wide door for us into the mining market.”
“In 2006, I spent six weeks on a worldwide tour visiting with dealers, OEMs and customers to compile a requirements list for new engines that would be required to meet Tier 4 emissions requirements. Looking ahead at the possible necessity for exhaust aftertreatment to meet that standard, they told us that they wanted minimal impact to engine installation-space requirements and minimal need for aftertreatment system care and maintenance in the mine,” he continued.
“As a result, in 2011, we released the first Tier 4i-compliant engine, and it was the only engine in its class that did not require exhaust aftertreatment,” said Eisenblätter.” This technology has been applied throughout our 1600 and 2000 series engines, and it again provides us with a unique selling proposition for the mining market.”
Eisenblätter likened the design of the company’s latest engines displayed at bauma to the preparation of a fine meal: “Everybody knows the basic ingredients that go into a great dish—the secret to success is how these ingredients are combined. In our case, we have several principal ingredients in engine design, such as two-stage regulated turbocharging with intercooling, exhaust gas recirculation, an advanced engine controller and optimized piston design for efficient combustion, and maximum fuel pressure. All of these technologies are well known in the industry, but our engineers—our ‘cooks’—know how to use them in the right combination, and to only use what’s needed and not more. That’s the secret of our success in this area.”
MTU also unveiled at bauma its Emission Flex Package, which enables customers to operate engines in countries where very different emission requirements may apply and available fuel has a high sulphur content. Using software designed specifically for the purpose, the engine’s exhaust gas aftertreatment system and SCR system can be deactivated; no hardware modifications are required. This solution also means that new vehicle designs will not require additional changes to the installation space needed to accommodate the engine.
Initially the Emission Flex Package will be offered as a retrofit solution for Series 900, 460 and 500 engines designed to meet EU Stage IIIB and Tier 4 Interim specs. The package is designed for EU Stage IV and Tier 4 compliance on new engines.
MTU mentioned that earlier this year its Capacitor Power System (CaPoS) had been installed for the first time, on three trucks operating in a mine in South Africa. An MTU spokesman said, “By installing CaPoS, we have been able to operate trucks equipped with Series 4000 engines using just four batteries instead of the usual eight, supplemented by two CaPoS modules. The customer is very pleased and can now reduce operating costs significantly with our product.”
CaPoS is a “maintenance-free” starter system that employs supercapacitors and replaces the vehicle’s starter batteries; it is claimed to improve battery service life fivefold. The system—which includes an integrated battery charger—is compact, less expensive, and has a higher degree of protection against dirt, grease and other contaminants, said MTU, and has been developed specifically for the demands of the mobile off-highway sector.
MTU’s Series 1000 to 1500 engines are jointly developed by MTU and Daimler, based on Daimler commercial vehicle engines, to meet EU Stage V regulations. These engines meet future EU Stage V emission limits using advanced internal engine technology, an SCR system and an additional diesel particulate filter.
Liebherr’s New Line
With its D96 and D98 engine series, Liebherr is launching two new diesel model lines in the range of 700 kW to 4,500 kW (940–6,000 hp). The first of the D96 series is a V20 unit rated at up to 1,500 kW (2,000 hp), compliant with EPA Tier 4 Final exhaust emission limits and available with SCR exhaust gas aftertreatment. Liebherr said it also is developing a nat-gas engine for stationary applications, based on D9620 design elements and with a power output of 1,070 kW. Production of the gas engines will start at the end of 2017.
Liebherr said its D98 series engines have the highest power density available in their market segment, providing up to 43.5 kW per liter. The D98 series will be available in three different cylinder layouts: a V12 that will be the first of the series to enter the market, followed by V16 and V20 configurations. As with the D96 series, an available SCR system will enable the D98 engines to comply with Tier 4 Final emission limits. Production of these new engines will start at the end of 2016 in Colmar, France, and Bulle, Switzerland.
Liebherr’s ECU3 engine control unit has been completely revised for the new generation of 11.2 common rail systems. Now an all-in-one system, it includes all control functions for the engine, the common rail system and exhaust gas aftertreatment.
Liebherr’s D98 series diesels will be available in three versions: a V12, shown here, followed by V16 and V20 configurations.
Volvo Penta: Maximum Versatility
Volvo Penta stated that its new 16-liter engine, designed for maximum flexibility in mobile applications, offers a wide range of benefits and features including improved fuel consumption, increased torque and a new turbocharger.
The TAD1643VE-B was developed in answer to customer requirements for a reliable, more compact off-road industrial powerplant, according to the company. OEMs and end users expressed a desire to find an alternative engine choice that is more suitable for the latest generation of mobile applications, where engine dimensions, weight and installation space are concerns.
The new 565-kW (750-hp) unit is based on Volvo Penta’s TAD1643VE, but with modified features that enable it to be installed in a wider range of machines. Those features include:
• New water-cooled turbocharger.
• New fuel injectors and more efficient combustion.
• Engine brake employing Volvo Group patented technology, offering 250-kW performance and tenfold higher engine brake capacity.
• Increased torque and torque curve.
• Electronically controlled wastegate, enhancing the engine’s overall capabilities for mobile, high altitude and stationary applications.
• An emissions reduction system that does not need Exhaust Gas Recirculation (EGR).
• Engine control unit (ECU) and electrical interface similar to the latest Stage IV/Tier 4 Final engine, enabling ease of installation.
• Upgraded engine management system.
• The highest output per liter of displacement in its class.
• Heavy-duty cooling packages, retarder thermostat housing, and a rear power take-off.
Naval Singh, Volvo Penta’s global segment specialist in mining and construction, said, “To keep the commonality of parts in customers’ installations, we followed the same engine footprint as the previous model as far as possible. For example, this new 16-liter TAD1643VE-B shares common electrical and physical interfaces with Stage IIIA, Stage IV and Tier 4 Final engines.
“We have seen substantial fuel savings during a long field trial period. Also, service intervals are longer, which means less downtime and more productive time available with machines,” he added.
Volvo Penta also announced it has approved the use of hydrotreated vegetable oil (HVO) fuels in all of its engines globally, enabling a potential reduction of fossil CO2 emissions by up to 90%. According to the company, its engines do not need any type of approval or specific certification for HVO usage.
HVO is a paraffinic fuel, also known as synthetic diesel, which can be produced from a variety of vegetable and animal sources. Regardless of whether it is used “neat” or blended with conventional diesel fuel, it can be used in any Volvo Penta engine without modifications. Additionally, there are no changes needed to service intervals and normal warranty conditions are applicable.
Volvo Penta’s new 16-liter engine, the TAD1643VE-B shown here, has been tested in underground mining mobile-equipment applications.
Cummins has eliminated the need for EGR on its latest generation of ultra-low-emissions engines built to meet the Stage V rules and spanning the 100–430 hp range. “Removing EGR allowed us to realize the full potential of the engine for Stage V without increasing displacement size. Our 12-liter QSM12 engine already pointed the way forward for a successful EGR-free design at Stage IV, so we were able to cascade this simpler approach down through the power range. No EGR also means there is less to cool, which will help lower the cost of OEM integration,” said Jim Fier, Cummins vice president, engineering, speaking at the company’s bauma engine reveal.
Cummins said its medium-duty, four-cylinder F3.8 and B4.5, and six-cylinder B6.7 and L9 engines offer significant performance improvements over Stage IV/Tier 4 Final equivalent engines, with at least 10% more power and almost 20% more torque averaged across the range. Improvements to fuel efficiency will drop the overall fluids cost of the new Stage V engines by 3% on average depending on application, compared with those of Stage IV versions. Operating costs will be further reduced with a 1,000-hour oil change interval, twice as long as the current 500 hours. Cummins’ renamed, non-EGR X12 and X15 engines complete the company’s current Stage V lineup, taking output up to 675 hp (503 kW) for heavy-duty applications.
Start-Stop technology is embedded in the engine management system, offering the potential to realize fuel savings of 5%–15%, corresponding to the amount of equipment idle time. Cummins said the Stage V engines are enabled for wireless connectivity to deliver instant engine diagnostics.
Across the Stage V range, each engine requires only a single Cummins turbocharger. Wastegate turbocharging is used for the F3.8, B4.5 and L9 engines, and the B6.7 retains variable-geometry technology. The higher power Cummins Stage V engines use urea-SCR for NOx control, while the F3.8 utilizes an engine-mounted DPF without SCR.
For both 4- and 6-cylinder engines, the increase in performance is applied across the full engine speed rpm range. This, said Cummins, makes the Stage V engines more adaptive for different machine-load demands, available either with high power at high engine rpm or high torque at low engine speed rpm.
In order to simplify and improve the exhaust aftertreatment technology needed to meet Stage V, Cummins will combine DPF, SCR and urea-dosing technologies into what it calls its Single Module, providing an up to 50% reduction in envelope size and a 30% reduction in weight compared with Stage IV exhaust aftertreatment.
The company described the Single Module as essentially a “fit-and-forget system,” capable of removing emissions almost entirely by passive regeneration, with no impact on equipment operation and requiring no operator intervention. The service cleaning interval is expected to extend significantly beyond the 5,000 hours of today’s systems. The modular design of the Single Module allows for varying diameters and lengths, to efficiently match catalyst capacity to the power output of the engine.
Cummins noted that its Stage V engines have a high degree of tolerance to sulphur in fuel—up to 5,000 parts per million—removing a major barrier in reaching the goal of a universal engine platform.
This capability offers OEMs the prospect of using the same Cummins Stage V engine in their equipment worldwide, overcoming the complexity of multiple emissions regulations in effect. For each machine, that will bring a common engine installation, with the same electronic integration and mechanical hookups, with or without exhaust aftertreatment, depending on emissions levels.
Meeting Stage V Regulations
The Stage V regulations to be introduced by EU countries will bring extremely stringent emissions regulations for construction, mining and material-handling equipment, commencing January 1, 2019. The key requirement for Stage V is a Particulate Number (PN) count of 1012/kW-hr—the maximum amount emitted for each kW of engine output per hour. The amount of Particulate Matter (PM) emitted by weight will drop to 0.015 g/kW-hr.
Taken together, the PN count and PM weight requirement in effect eliminate 99.9% of all PM, which requires the use of a Diesel Particulate Filter (DPF). Additionally, oxides of nitrogen (NOx) emissions will be set at the extremely low level of 0.4 g/kW-hr, requiring the use of Selective Catalytic Reduction (SCR) aftertreatment. Engines above 751 hp (560 kW) are included in the Stage V regulations, but do not require the PN count.