Liebherr Exhaust Gas Aftertreatment Systems for Diesel Engines · Liebherr Exhaust Gas Aftertreatment Systems for Diesel Engines Efficient Systems for Reduced Emissions

Liebherr Exhaust Gas Aftertreatment Systems for Diesel EnginesEfficient Systems for Reduced Emissions

2 Exhaust gas aftertreatment systems from Liebherr

State of the art diesel engines are measured not only by their performance and consumption but also by the amount of harmful substances they emit. For its diesel engines, Liebherr has therefore developed a whole range of innovative and efficient exhaust gas aftertreatment systems, including high-precision controlled injection technology. The systems reliably reduce exhaust gas emissions and harmful particulates and comply with the exhaust gas regulations of a wide range of countries and regions. The systems with particulate filter or SCR catalytic converter are designed for use in mobile machinery and can be integrated well in the equipment.

Effective exhaust gas aftertreatment systems from Liebherr

Exhaust gas aftertreatment systems from Liebherr 3

General legislative conditions

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Tested systems with high quality

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System solution DOC, POC and DPF97/68 EC Stage IIIB and USA EPA CARB Tier 4 interim

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System solution EGR, DOC and DPF97/68 EC Stage IIIB and USA EPA CARB Tier 4 interim

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System solution SCR97/68 EC Stage IIIB and USA EPA CARB Tier 4 interim

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System solution SCR97/68 EC Stage IV and USA EPA CARB Tier 4 final

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All from one source for 97/68 EC Stage IV and USA EPA CARB Tier 4 final

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Liebherr engines with exhaust gas aftertreatment

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Example of use in earth moving equipment97/68 EC Stage IIIB and USA EPA CARB Tier 4 interim

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Example of use in crane97/68 EC Stage IIIB and USA EPA CARB Tier 4 interim

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Engine output in kW 2010 2011 2012 2013 2014 2015

56 to 130

130 to 560 Stage IIIA / Tier 3

Stage IIIA / Tier 3 Stage IV / Tier 4 final

Stage IV / Tier 4 final

Stage IIIB / Tier 4 interim

Stage IIIB / Tier 4 interim

Emissions legislation in USA and Europe (offroad vehicles)

Tier 4f

Tier 3

130 – 560 kW US standard EPA CARB

130 – 560 kW 97/68 EC standard

NOx [g/kWh]

PM [g/kWh]

0.20

0.15

0.10

14 23 32 41

0.05

NOx [g/kWh]

Tier 4iStage IIIB

Stage IV

Stage IIIA


General legislative conditions (offroad vehicles)

Today‘s emissions legislation for offroad applications in Europe and the USA necessitate the use of exhaust gas aftertreatment systems. Liebherr assumed the responsibility of developing engines with low emissions and, at the same time, high performance. Aside from the 97/68 EC standard and US EPA CARB standard, Liebherr also complies with other local regulations because the exhaust gas aftertreatment systems are modular in design.

97/68 EC Stage IIIBUSA EPA CARB Tier 4i

The regulations of the emissions standard 97/68 EC Stage IIIB and USA EPA CARB Tier 4 interim came into force as long ago as 2011 for engines of power category 130 to 560 kW. These regulations demand a reduction of particulate emissions by approx. 90 % as well as a reduction in nitrogen oxides by 50 %. In order to comply with these requirements, either particulate filters or SCR systems can be used. Together with renowned partners, Liebherr has developed both systems for its engines and adapted them to the applications accordingly.

97/68 EC Stage IVUSA EPA CARB Tier 4f

From January 2014, the regulations will become even stricter through the introduction of the EU Stage IV and USA Tier 4 final standards. These require that nitrogen oxides be reduced by a further 80 %. This additional major reduction in the emissions thresholds represents a major challenge to engine manufacturers. Liebherr used this as an opportunity to completely revise its diesel engines and notably enhance its system expertise as a diesel engine manufacturer by developing its own injection system, including engine management. For exhaust gas aftertreatment, Liebherr relies entirely on SCR technology. Thanks to ideal system integration, the particulate emissions are already below the thresh-olds within the engine. This means that there is no need for particulate filters such as DOC and DPF.

Generated in the engine from combustion are:

Nitrogen oxides (NOx) Nitrogen oxides are the product of a reaction between oxygen and nitrogen during combustion.

Particulate matter (PM) Particulates are mainly particles of carbon that are generated during combustion.

Hydrocarbons (HC) Unburned fuel remains in the exhaust gas as a hydrocarbon compound.

Carbon monoxide (CO) The combination of carbon and oxygen is caused during combustion in the event of air deficiency.

Carbon dioxide (CO2), water vapour (H2O) Aside from water, every combustion process generates carbon dioxide.

NOx [g/kWh]

PM [g/kWh]

Tier 3 4 0.2

Stage IIIA 4 0.2

Tier 4i 2 0.02

Stage IIIB 2 0.025

Tier 4f 0.4 0.02

Stage IV 0.4 0.025

Thresholds for NOx and particulates:


CFD simulations The geometry of the exhaust gas aftertreatment systems has already been optimised by means of CFD analysis in order to achieve a higher level of efficiency and performance.


Tested systems with high quality

Modern measuring devices 3D measuring machines with measuring accuracy down to the µ-range offer the best prerequisites for attaining the level of quality expected by the customer. Parts from inhouse production are checked on a continual basis. Parts produced externally are submitted to a receipt inspection procedure.

Test benches Together with the engines, the ex-haust gas aftertreatment systems are checked on the test benches under realistic conditions. Long-term tests allow conclusions to be drawn regarding the service life and highlight areas of potential optimisation that can be taken account of in the course of further development.

The exhaust gas aftertreatment systems developed by Liebherr are examined and tested to a great extent in order to safeguard their operability and longevity. All components are distinguished by a simple, robust design and are thereby ideal for the rigours of tough mobile machinery deployment.

Engineering know-how

To develop the exhaust gas aftertreatment systems, modern design and simulation programs are used. These flag up potential optimisation measures even during the design phase and facilitate checking and improvement of the operability and performance.

Trials For a high level of quality and reliability of the exhaust gas aftertreatment systems, these run through com-prehensive test programs on test benches with modern equipment even in the course of development. The results serve also to verify the bases of calculation.

Quality assurance To safeguard quality, Liebherr uses a contemporary computer-assisted quality management system (CAQ system) that is implemented as early as the production creation process and covers the entire product life cycle. Statistical assessments, FMEA (Failure Mode and Effects Analysis) and CIP (Continuous Improve-ment Processes) are examples of a consistent process philosophy.

Highest quality and safety standards

The Liebherr site in Bulle is certified according to DIN EN ISO 9001:2008 and works around VDA standards (reliability control loop). Liebherr SCR systems are ATEX-certified so as to allow operation in potentially explosive atmospheres.


Diesel oxidation catalyst (DOC) The maintenance-free diesel oxidation catalyst cleans the exhaust gas of carbon monoxide (CO) and deposits from unburned fuel by oxidizing these components into carbon dioxide (CO2) and water (H2O). Nitrogen and nitrogen monoxide (NO) are also oxidized into nitrogen dioxide (NO2).

Exhaust gas

Exhaust gas

Exhaust gas

Cleanedexhaust gas


System solution DOC, POC and DPF97/68 EC Stage IIIB and USA EPA CARB Tier 4 interim

Diesel particulate filter (DPF) At the end of enclosed channels, the exhaust gas is forced to permeate the porous walls of the filter, which trap the particulates.

Particulate oxidation catalyst (POC) The particulate oxidation catalyst comprises thin steel film layers and a sintered metal fleece in which the filtered particles are stored. Once the temperature is high enough and the concentration of nitrogen dioxide (NO2) is sufficient, the stored par-ticulates are oxidized or burnt off. The filter constantly cleans itself and requires little maintenance.

Cleanedexhaust gas

Cleanedexhaust gas

In order to fulfil the various national emissions regulations, such as 97/68 EC Stage IIIB and USA EPA CARB Tier 4i, Liebherr employs various systems: diesel oxidation catalysts (DOC), particulate oxidation catalysts (POC) and diesel particulate filters (DPF). In this way, the machines can be adapted specifically to comply with regional or deployment-related rules and regulations. The most economic solution is sought in each case respectively.

Diesel oxidation catalyst (DOC)

The specially coated surfaces of diesel oxidation cat-alysts break down the carbon monoxide and hydrocarbons into harmless substances such as water and carbon dioxide. Any nitrogen in the exhaust gas is oxidized into nitrogen dioxide which is needed in the downstream POC systems. The DOC system has been tried and tested over many years of use and is maintenance-free.

System solution DOC and POC

If the DOC system is no longer sufficient on higher performing engines, a particulate oxidation catalyst is introduced. The POC system is a partial flow filter and cannot become blocked owing to its open structure. An upstream oxidation catalyst is required to supply the required nitrogen dioxide.

System solution DOC and DPF

If a DOC/POC system’s performance also fails to meet the applicable regulations in terms of particulate emis-sions, a particulate filter (DPF) is used. Very strict thresh-olds apply above all in tunnel construction or in enclosed halls as well as in Switzerland. In these cases, diesel particulate filters (DPF) are used that offer very high deposition rates as wall flow filters. The particulate filter with ceramic filter element that Liebherr employs withholds practically 99 % of the soot particles. If the temperature is high enough and there is a sufficient quantity of nitrogen dioxide, the filter regen-erates itself by “burning off” the soot particles (passive regeneration). The option of actively regenerating the particulate filter is not available for DOC/DPF systems.


HC doser (fuel dosing unit) If the temperatures are not high enough for passive regeneration of the particulate filter, the thermal management system actuates the dosing unit and a precisely metered quantity of fuel is injected into the exhaust gas in front of the DOC.

Exhaust gas

Electrical wiring

CAN bus

Fuel

Temperature sensor

Differential pressure sender

Control unit

CAN bus

Liebherr engine control unit

HC doser

Injector unit

Differential pressure sender

Mixer

© PURItech GmbH & Co. KG


System solution EGR, DOC and DPF97/68 EC Stage IIIB and USA EPA CARB Tier 4 interim

Removable DPF The Liebherr diesel particulate filter is distinguished by easy handling and long cleaning intervals. In this way, the middle module can be removed easily thanks to patented O-rings. Perma-nently installed, non-rotating module brackets ensure that installation of the filter module is always correct.

Cleaned exhaust gas

Cleaning procedure The particulate filter to be cleaned is decontaminated using a special method by authorised Liebherr service partners.

To comply with EU Stage IIIB and EPA Tier 4i in Liebherr diesel engines that are installed in earth moving equipment, a combination of diesel oxidation catalyst (DOC), diesel particulate filter (DPF) and exhaust gas recycling (EGR) is used (EGR is not shown in the diagram on the left). Together with a thermal management system, a HC dosing unit safeguards active regeneration of the particulate filter.

Exhaust gas recycling (EGR)

Exhaust gas recycling facilitates the reduction of nitrogen oxides and adherence to their thresholds. By recycling part of the exhaust gas and feeding it into the engine in-take air, the amount of oxygen is reduced. This reduces the combustion temperature as well as the nitrogen oxide that is produced.

Passive regeneration Depending on the engine load, the exhaust gas temper-ature is sufficient to continually oxidise the soot particles in the particulate filter, i.e. burn them off. For this passive regeneration of the filter, nitrogen dioxide is required which is formed in the DOC element.

Active regeneration Because of the fluctuating load profiles in mobile machinery, the particulate deposits are often not removed completely through passive regeneration alone. Together with an injection of fuel by a HC dosing unit, the Liebherr thermal management system ensures that temperature is increased, thereby promoting the chemical regeneration process. The system is designed for a long service life in varying operating demands.

Cleaning cycle Despite active and passive regeneration, deposits still remain in the filter element, e.g. ash from the lubrication oil. For this reason, the DPF element must be removed on a regular basis and mechanically cleaned, for example at the Liebherr Reman Competence Centre in Ettlingen. Removal and installation of the filter is engineered to be fast thanks to numerous design measures.

ATEX certification To enable Liebherr SCR systems to be deployed in potentially explosive atmospheres. The system solution EGR, DOC and DPF is ATEX certified.


Nitrogen oxide (NOx)

Ammonia (NH3)from diesel

exhaust fluid

Nitrogen (N2)Water (H2O)

Chemical reaction In the SCR catalyst, the ammonia in the diesel exhaust fluid reacts with the nitrogen oxides from the engine exhaust gas. This results in non-toxic nitrogen and water vapour.

Exhaust gas

Injector Hydrolysis catalyst

SCR and slip catalytic converter

DEF tank

Engine heat

Engine coolant

Heater circuit valve

DEF pump

DEF control unit


Communicates withNOx sensors anddiesel exhaust fluid control unit

Electrical wiring

CAN bus

Temperature sensor

NOx sensor

Fill level sensor

CAN bus


System solution SCR97/68 EC Stage IIIB and USA EPA CARB Tier 4 interim

Diesel exhaust fluid tank and line To prevent the diesel exhaust fluid from freezing at low temperatures, the Liebherr tank, pump and lines are heated.

Diesel exhaust fluid injector The diesel exhaust fluid injector used by Liebherr is distinguished by particularly fine atomisation of the fluid. In this way, the chemical reactions are brought relia-bly into operation and the diesel exhaust fluid consumption is minimised.

Cleanedexhaust gas

In Liebherr diesel engines that comply with emissions level EU Stage IIIB and EPA Tier 4i for mobile cranes and crawler cranes, an SCR system is used for the exhaust gas aftertreatment. Due to the high temperatures in the SCR system, a spark arrester is employed for purposes of ATEX certification and for operation in areas with a threat of explosion.

Selective catalytic reduction

With selective catalytic reduction, the nitrogen oxides present in the exhaust gas are chemically reduced. To do this, a diesel exhaust fluid solution (diluted urea solution) is mixed into the exhaust gas by means of an injector. In the hydrolysis catalyst, ammonia and CO2 are formed from this. The coating in the SCR catalyst, subsequently causes the ammonia and nitrogen oxides to react, resulting in non-toxic nitrogen and water va-pour.

Higher engine operating efficiency

Through optimisation of the combustion processes in the engine and the adaptation of the injection procedure, it was possible to improve engine efficiency and fuel consumption. When adjusted optimally, a Liebherr engine with SCR system will consume up to 8 % less fuel.

Maintenance-friendly system

As open systems, SCR catalysts do not need to be main- tained or cleaned as no particles can become deposited on them. Through harmonisation of the diesel and diesel exhaust fluid tanks, these can be replenished at the same time.

Diesel exhaust fluid (DEF)

Diesel exhaust fluid is a synthetically-manufactured urea solution. It is non-toxic and available in Europe, North America (under the designation DEF, i.e. Diesel Exhaust Fluid) and in many of the other countries of Liebherr service partners as well as at filling stations.


Diesel exhaust fluid injector The newly developed injection of air and diesel exhaust fluid enables high atomisation and thereby even greater efficiency in the reduction of nitrogen oxides compared with the SCR system for EU Stage IIIB and EPA Tier 4f.

Exhaust gas

Air pump

DEF pump

Air

Heater circuit valve

Injector

DEF tank

Mixture path

SCR and slip catalytic converter

Communicates with all components and sensors

Temperature sensor

Electrical wiring

NOx sensor

CAN bus

NH3 sensor

Fill level sensor

Quality sensor

Engine coolant


CAN bus


System solution SCR97/68 EC Stage IV and USA EPA CARB Tier 4 final

Diesel exhaust fluid pump With the SCR system for Stage IV and Tier 4 final, a new diesel exhaust fluid pump is used that is distinguished above all by its reliability and sturdiness. It is adapted optimally to the entire system.

Air pump The air pump draws in filtered air and ensures that a precise quantity of air is mixed with the diesel exhaust fluid injection.

Cleaned exhaust gas

Introduction of the emissions standards EU Stage IV and EPA Tier 4f requires nitrogen oxides to be reduced by a further 80 %. To adhere to these thresholds reliably, Liebherr has further developed the SCR technology. Due to continual, precise control of the exhaust gas by means of an OBD control loop (onboard diagnosis) and considerably greater SCR catalyst effectiveness, a very high level of system efficiency is achieved.Better and more precise metering is made possible by modifying diesel exhaust fluid injection with different injectors and by adding more air to the mix.

Particulate reduc-tion without DPF and DOC

Thanks to intensive engine optimisation measures and the ideal harmonisation of inhouse-developed injection with the company’s own engine control unit, the particulate emissions within the engine are already below the thresholds. This means that further particulate reduction measures such as DOC and DPF can be dispensed, leading to a very reliable system.

Installation space advantage

Despite the increased demands from Stage IV and Tier 4f in terms of the emissions, the installation space needed for the Liebherr engine and exhaust gas aftertreatment system remains the same as that for Stage IIIB and Tier 4i. It is very small compared with other systems.

Reduced complexity The simple system structure with just a few compo-nents, e.g. no cooled exhaust gas recycling, meant that optimal solutions could be found for requirements such as modularity and user-friendliness.

Simplified fault diagnosis

With the SCR system for EU Stage IV and EPA Tier 4f, all control functions of the diesel engine and exhaust gas aftertreatment system are housed in one engine control unit. This enables optimal monitoring of the functions and direct fault diagnosis.


Common rail system The common rail system developed by Liebherr with reliable multiple injection at pressures up to 2000 bar, contributes decisively towards the reduction of par-ticulates within the engine.


Exhaust gas aftertreatment To reduce nitrogen oxides downstream from the engine, Liebherr relies entirely on SCR technology for Stage IV and Tier 4 final. The catalyst is extremely space-saving.

Liebherr engine control unit The Liebherr engine control unit controls and regulates all of the requisite injection parameters in consideration of the measured emission levels.

Liebherr approaches the rising emissions requirements with system expertise in the field of engine manufacturing. In addition to engine assembly, the injection system, engine management and exhaust gas aftertreatment systems are devel-oped in-house. The optimal harmonisation of the components in the Stage IV and Tier 4f-generation of diesel engines enables a reduction of particulate emissions within the engine to values that are better than the legally prescribed limits. Through ideal system integration, it was even possible to improve consumption and performance.

Common rail injection system

The injection system is decisive for the combustion process and thereby the generation of emissions. Liebherr has developed its own common rail injection system, which has been ideally tuned to the Liebherr diesel engines. Reliable multiple injection, pressures up to 2000 bar and an injection jet precisely adapted to the cylinder geometry ensure the most effective combustion possible during which only a small amount of emissions are generated.

Electronic engine control unit

The Liebherr-developed engine control unit combines all of the functions for regulation of the engine, injection, exhaust gas aftertreatment and functions of equipment close to the engine. Using a variety of measured parameters, the control unit calculates in realtime not just the ideal injection timing and the ideal quantity of fuel for each cylinder but also the timing and quantity of injection for the diesel exhaust fluid.

Exhaust gas aftertreatment

The SCR system, developed by Liebherr without exhaust gas recirculation and without a DOC and is there-fore extremely robust - even when used with Ultra low sulphur fuel. Since an additional particulate filter is generally not needed, it is extremely space-saving in terms of installation.

All from one source for 97/68 EC Stage IV and USA EPA CARB Tier 4 final



Liebherr engines with exhaust gas aftertreatment

Emissions regulation Application Exhaust gas aftertreatment system

Engine Power [kW] Capacity [l]

97/68 EC Stage IIIB /USA EPA CARB Tier 4 interim

Earth movingmachinery

DOC D834 110 4.6

DOC + POC D834 120 4.6

DOC + DPF D834 110/120 4.6

DOC + DPF + EGR (depending on application)

D934 160-175 7.0

D936 240-270 10.5

Mobile cranesCrawler cranesMobile harbour cranes

SCR D934 160-180 7.0

D936 240-300 10.5

D856 350-390 12.4

D9508 400-505 16.2

97/68 EC Stage IV /USA EPA CARB Tier 4 final

All applications SCRonly D934 160-200 7

D944 200-230 8

D936 240-320 10.5

D946 300-380 12

D9508 405-505 16.2

USA EPA CARB Tier 4 final All applications SCRonly D9512 565-750 24.2



Example of use in earth moving equipment 97/68 EC Stage IIIB and USA EPA CARB Tier 4 interim

The exhaust gas aftertreatment system comprises exhaust gas recycling (EGR), diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) for EU Stage IIIB and EPA Tier 4i and is used by Liebherr in earth moving equipment, such as wheeled excavators. The tried and tested and robust technology is ideal for challenging environmental conditions and the toughest of operations. The DOC DPF units need only a small amount of installation space and can be serviced quickly by Liebherr-trained service personnel.



Example of use in crane97/68 EC Stage IIIB and USA EPA CARB Tier 4 interim

The Liebherr exhaust gas aftertreatment system with SCR catalyst for the emis-sions directives of EU Stage IIIB and EPA Tier 4i is used in mobile cranes and crawler cranes as well as mobile harbour cranes. Unlike with diesel particulate filters, regular maintenance is not necessary. Nevertheless, diesel exhaust fluid is required for the catalysis.

Liebherr-Component Technologies

Liebherr-Component Technologies AG, based in Bulle, Switzerland, is responsible for all activities of the components division of the Liebherr group. The companies and business areas belonging to this division are specialised in the development, design, manufacture and reconditioning of high-performance components in the field of mechanical, hy draulic and electrical drives and control technology. The sale of components to customers outside the Liebherr group of companies is managed centrally by Liebherr-Components AG in Nussbaumen, Switzerland.

Biberach / Riss (Germany): large diameter bearings, gearboxes, rope winches, switchgear, electronics, electrical machines

Lindau (Germany): electronics, power electronics

Bulle (Switzerland): diesel engines, gas engines, splitter boxes, axial piston units, injection systems

Ettlingen (Germany): remanufactured components

Kirchdorf (Germany): hydraulic cylinders

Monterrey (Mexico): large diameter bearings

Many Years of ExperienceLiebherr has decades of experience in the manufacture of high-quality components used in cranes and construc-tion machines, in the mining industry, maritime applica-tions, wind turbines, in vehicle technology or in aerospace and transportation technology.

The Right Solution for Every NeedA high degree of vertical integration and the use of flexi-ble, state-of-the-art production systems allow Liebherr to offer its customers tailor-made solutions. Liebherr is your partner for joint success – from the product idea to devel-opment, manufacture and first installation right through to series production. For the various components of the drivetrain, Liebherr also offers remanufacturing in various degrees in a dedicated factory.

System Solutions from a Single SourceComponents from Liebherr are perfectly matched to each other with regard to operation. Depending on the require-ment, individual components from the wide product range can be expanded through to the complete drivetrain. This results in impressive system solutions which can be inte-grated into a variety of applications.

Highest Quality Standards and Long Service Life All components meet the very highest demands for func-tional reliability and durability, even under extreme loads and harsh conditions. Elaborate quality management and extensive analysis and test procedures are practised throughout the entire development and production process, guaranteeing reliability and long component service life.

www.liebherr.com

Dalian (China): gearboxes

Liebherr Machines Bulle S.A.45, rue de l’Industrie, CH-1630 Bulle +41 (0)26 913 3111, Fax +41 (0)26 913 34 85www.liebherr.com, E-Mail: [email protected]

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Liebherr Exhaust Gas Aftertreatment Systems for Diesel Engines · Liebherr Exhaust Gas Aftertreatment Systems for Diesel Engines Efficient Systems for Reduced Emissions