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Complying with emission regulations is a necessity, and to address those standards, manufacturers are steadily improving the efficiency of their engines used in cranes and other types of heavy equipment.
In the U.S., the EPA tier 4 final standard is now required and in Europe, engines must meet EU stage IV emissions regulations. Tier 4 final standards and the similar stage IV regulations require a significant emissions reduction, including 55% lower NOx and a drop of 80% in particulate matter (PM) compared to tier 2 levels.
“Our engines comply with the latest exhaust emissions standards for both the U.S. and Europe,” said Dr. Ulrich Hamme, technical director at Liebherr-Werk Ehingen GmbH. “That allows us to supply them worldwide, in both countries with high and lower regulations.”
Most Liebherr cranes are powered by the manufacturer’s engines from Liebherr Machines Bulle SA and are equipped with ZF gearboxes. One exception are Liebherr rough terrain LRT series models, which feature Cummins engines and gearboxes from Dana.
All Liebherr crane engines are also HVO-ready. Hydrogenated vegetable oils are fats — mainly obtained from vegetable oil and cooking waste oil — that are converted into hydrocarbons with the addition of hydrogen.
“The fuel can be used in any mixture, even as a pure fuel,” Hamme explained. “This significantly reduces greenhouse gas emissions. Compared to diesel fuel, over the lifecycle of a five-axle mobile crane, CO2 emissions are reduced by 74% when pure HVO is used.”
Cummins makes a range of off-highway diesel engines that meet both EPA tier 4 final and EU stage IV emissions standards. The regulations affect the manufacturer’s high horsepower engine family, which includes the QSK19, QSK23, QST30, QSK38, QSK50, QSK60, QSK78 and QSK95 models. These engine platforms optimize in-cylinder diesel combustion and utilize selective catalytic reduction (SCR) to meet tier 4 final emissions.
Next generation Cummins QSK engines feature integrated SCR aftertreatment designed and manufactured by Cummins Emission Solutions. By focusing NOx reduction within the exhaust rather than during in-cylinder combustion, the SCR system avoids major changes to the external engine platform, the manufacturer explained, and leaves a much higher performance threshold in-cylinder to focus on PM reduction.
Cummins Off-Highway Engines Include:
Closer to Zero Emissions Alternatives
Working to meet growing demand for greener equipment, Liebherr has unveiled the LTC 1050-3.1 compact crane that features an electric motor in addition to a conventional internal combustion engine.
“The alternative version of the LTC 1050-3.1 delivers the best possible combination of green credentials,” said Hamme. “The machine has a conventional internal combustion engine powered by diesel or HVO for driving on roads and for crane operations. It also has an electric power unit so crane operations can generate zero emissions on the job site.”
The diesel and electric powered LTC 1050-3.1 — a 50-USt crane with a 118-foot telescopic boom and a maximum hoist height of 157 feet — is equipped with a 326-HP, six-cylinder emissions-compliant Cummins diesel engine. The crane’s 72 kW electric motor uses an existing hydraulic pump, which is mounted on the powershift transmission, to transfer power to the superstructure.
Only the electric motor and a distributor gear and required control equipment must be added to a conventional LTC 1050-3.1 model to transform it into an electric version. The distributor gear is located between the crane pump and the powershift transmission.
Site current at 125 amps is required for full performance of the diesel and electric LTC 1050-3.1 model, but the crane can also be operated with a 63-amp power supply. It can also run using an external conventional battery pack if the job site does not have the necessary electrical infrastructure.
“Regardless of whether the crane is powered by its zero emissions electric motor or its internal combustion engine, all of its familiar properties are retained,” Hamme related. “The electric motor enables the crane to be operated without restriction, in other words with almost the same performance as using the six-cylinder engine.
“Choosing the electric motor crane mode reduces both air and noise emissions to a minimum,” Hamme added. “That means that the machine is suitable for use in sensitive areas. This simple solution enables the operator to switch between diesel-hydraulic and electro-hydraulic power, depending on the conditions of the job.”
Among the ways that Cummins is addressing the need to meet decarbonization goals with suitable low-carbon alternatives for off-highway equipment is to advance the development of hydrogen internal combustion engines (ICE).
Hydrogen ICE power plants burn fuel to generate heat and mechanical energy in the same way as conventional combustion engines, Cummins explained. Hydrogen ICEs also decarbonize off-highway work sites with their 99%-plus reduction in carbon emissions as compared to diesel engine powered equipment.
A major benefit of hydrogen combustion engines is that they are built on a familiar architecture. A hydrogen ICE can be installed in the same equipment as a diesel engine while also using the same transmission, cooling systems and hydraulic systems. Maintenance practices and costs are also comparable to diesel engines.
Cummins is planning to offer two hydrogen internal combustion engines, available in 6.7- and 15-liter variants. The engines are part of the manufacturer’s new fuel agnostic platform, where below the head gasket each fuel type’s engine remains the same.
One major consideration for hydrogen engines is the on-board fuel storage system, which Cummins has added to its technology portfolio with the Cummins and NPROXX joint venture.
Fueling infrastructure is also a critical element for off-highway applications and hydrogen is well suited for distribution because it can be transported in the same way as diesel fuel. Hydrogen has the added flexibility of local onsite production using an electrolyzer with renewable energy. Furthermore, existing natural gas infrastructure can be converted to transport hydrogen at a low cost.
Industries that require high load factors and high equipment utilization face the biggest challenge in finding viable low-carbon and zero-carbon solutions. Hydrogen is well suited for those off-highway applications where users can benefit from quick refueling times and diesel-like performance, durability, and reliability, Cummins noted. Leveraging platforms with low-carbon and zero-carbon fuel will help industries dramatically reduce greenhouse gas emissions.
