You will find the figures mentioned in this article in the German issue of MTZ 05I2007 beginning on page 356.
Die neue Generation der MTU-Baureihe 4000
The New Generation of the MTU Engine Series 4000
Stricter emission limits and rising performance demands were the driving forces behind the further development of the Series 4000 diesel engines made by MTU Friedrichshafen. These high-speed off-highway engines are designed for applications in the construction machinery, power generation, rail and marine sectors. A new addition to the range is the 20V 4000 marine engine which develops 4300 kW. Despite higher power outputs and compliance with tighter emission restrictions, the engines’ fuel consumption is the same or lower than before.
1 Engine Design Concept Authors: Martin Kurreck, Werner Remmels, Michael Eckstein, Otto Bücheler and Volker Wachter
The Series 4000 in cylinder configurations of V8, V12, V16 and V20 has been in volume production at MTU for more than ten years and the new generation of the engine was able to make use of many proven components. One feature that has been changed for all applications is the bore – it has been increased by 5 mm. In addition,
the stroke has been increased from 190 to 210 mm for the rail, power generation and construction machinery applications. Both the standard and longer-stroke engines use the same, thoroughly proven crankcase, Figure 1, made of a special type of cast iron. The one-piece crankcase is made of a special type of cast iron. The main oil channel and the coolant channels are integral features. The crankshaft MTZ 05I2007 Volume 68
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is machined on all sides and has bolt-on counterweights. The wear-resistant plain bearings are a new design. The drive is delivered by a choice of either standard or long-stroke crankshaft with bolt-on counterweights. The pistons consist of an aluminium skirt with a screwfitted steel crown, while the cylinder liners are spin castings with a two-stage plateauhoned finish. The cylinder head design with centrally positioned fuel injector and two inlet and two exhaust valves has also been carried over. In order to be able to economically serve the broad spectrum of applications and their varying requirements, MTU uses a standardized basic engine. Application-specific characteristics are then created by adapting the combustion process, turbocharging, cooling system and electronic management. Uncooled exhaust pipes are used for the rail and power generation applications, while marine and construction machinery versions use water-cooled triplewalled exhaust systems. The cooling system for rail, power generation and construction machinery applications consists of a hightemperature and a low-temperature circuit. The single-circuit cooling system for marine applications is exceptionally easy to maintain and is characterized by outstanding performance at low loads.
engine management electronics and even more powerful turbocharging it has been possible to optimize the combustion processes. The three-phase fuel injection has also been a significant contributor in that regard. As a result, compliance with the roughly 30 % lower exhaust emission limits has been achieved solely by internal engine design modifications and without sacrificing low fuel consumption. Exhaust aftertreatment measures have not been necessary. The high-pressure system can be composed of either single or double-walled fuel lines. With the double-wall design – standard for marine and rail applications – leaks at high-pressure seals can not escape to the outside and are contained within the fuel leakage space and detected by a central sensor. This design therefore offers maximum safety. The existing common-rail system was hydraulically optimized and redesigned with the aid of computer simulations so as to minimize emissions and fuel consumption. The result is a modular fuel injection system with unit accumulators integrated in the injectors. Figure 2 shows the overall system layout, while the injector design can be seen in Figure 3. It allows Injection volumes of up to 1000 mm3 at a system pressure of 1800 bar, integral volume limiter valve and multi-phase injection capability. A low-pressure pump driven by the highpressure pump draws the fuel from the tank and delivers the compressed fuel to the high-pressure pump. This multi-cylinder, oil-lubricated, roller-tappet inline pump is a new design developed by L’Orange to handle the higher system pressure and greater delivery volumes required.
1.1 Fuel Injection A key feature of the Series 4000 is the advanced common-rail fuel injection with a high-pressure inline pump and “Lead” fuel injectors with unit fuel accumulators. A virtually uniform pressure of 1800 bar is maintained throughout the system. Through the combination of the new ADEC
A high-pressure fuel line takes the fuel from the pressure chamber integrated in the high-pressure pump connector block into the distributor block which accommodates the high-pressure sensor, temperature sensor and pressure-relief valve. From the distributor block, separate fuel lines lead to fuel rails on each side of the engine. The fuel rails do not act as a pressure accumulators but merely perform the function of fuel pipes. The hydraulic resistance ahead of each injector is created by a flow restrictor bore in the adaptor. The volume limiter valve already used on the Series 4000.01 and 4000.02 common rail systems between the fuel rail and the injector pipe has been integrated in the injector’s accumulator chamber for the Series 4000.03. The volume limiter valve closes if, for instance, if the injector valve needle sticks in the course of an operating cycle and so prevents continuous injection of fuel. The injectors for the Series 4000.03 are a new design produced by L’Orange to meet the requirements in terms of integral pressure accumulator, 1800 bar system pressure and multi-phase injection. In order, firstly, to create the space for the unit accumulator and, secondly, to achieve the multiphase injection capability demanded, the control valve had to be placed as close to the injector nozzle as possible. This allowed the moved masses to be substantially reduced in comparison with the previous Series 4000 injectors. The new design allows the achievement of very short time lags between application of the control current and actual commencement of the injection sequence. The fundamental modular design of the injector comprising integral unit accumulator, solenoid, control valve, flow restrictor and nozzle module is illustrated in Figure 3. The injector is operated by a 2-way/2-port valve that is controlled by the engine management electronics.
1.2 Engine Management
Figure 1: One-piece crankcase of the MTU series 4000 12
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Another significant innovation on the new Series 4000 is the new generation of MTU’s own ADEC (Advanced Diesel Engine Control) electronic engine management system, Figure 4. The ADEC module incorporates, among other things, electronic circuitry capable of a three-phase injection sequence (pre, main and post-injection phases) that delivers optimum control of the fuel injection process in terms of low-emission and power-efficient combustion. The engine management system is torque-regulated. As a result, a high degree of control precision is achieved. The application type and specific adaptation
param for an individual engine when delivered are defined by the data maps stored on the ADEC. In addition, engine operating data such as hours of duty recorded by the ADEC can be remotely accessed or copied to a new module in the course of engine servicing.
1.3 Turbocharging The marine, rail and construction machinery engines are equipped with MTU highperformance turbochargers. They are characterized by high charge pressures and turbocharger efficiency. The construction machinery engines, for instance, can be operated at altitudes of up to 3700 m, while the surface temperatures of the C&I and marine engine turbochargers are kept low by water-cooling. The ZR 195 turbocharger with its 205 mm impeller, Figure 5, spins at up to 54,000 rpm delivering a maximum 4.7 bar of charge pressure and 2.2 m3 of airflow. The Series 4000 engines use multi-stage turbocharging with up to four turbochargers.
2 C&I Engine The Series 4000 C&I (construction and industrial) engines are used in the world’s largest dump trucks, excavators and wheeled loaders. The V12, Figure 6, V16 and V20 models span a range of power outputs from 1193 to 2800 kW at 1800 rpm. This represents an increase of roughly twelve % compared to the predecessors. The main requirements placed on the C&I engines are high levels of availability and reliability, low surface temperatures and high operating altitudes. With a fuel consumption of 207 g/kWh the engine satisfies the more stringent EPA Tier II emission limits (as per 40 CFR 89), specifically: – NOX + HC c 6.4 g/kWh – CO c 3.5 g/kWh – particulates c 0.2 g/kWh. The turbocharging system on the C&I engines has been further refined. Two highly efficient turbochargers on each engine compress the charge air up to pressures of as much as 3.5 bar. The engines can operate at altitudes up to 3700 m without loss of power. The water-cooled exhaust system is unrivalled in C&I applications. It keeps the engine surface temperature below 200 °C and prevents the possibility of fire in case of oil leakages from the vehicles’ hydraulic system contacting the engine. Consequently, the fire risk on mining trucks is significantly lowered and operators benefit from increased availability.
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The C&I engines are available as versions with enhanced power as well as emissionsoptimized or fuel consumption-optimized, Table.
3 Genset Engine The Series 4000 genset engines, Figure 7, are used for emergency power, mobile and stationary continuous duty, and peak-load power applications. In general they are characterized by excellent load-response, high power density and outstanding economy. The 50-hertz version covers a range of power outputs from 1420 to 2850 kW at 1500 rpm. There is also a 60-hertz version for the US market offering between 1520 and 3490 kW at 1800 rpm. The new generator engines for 60-Hz applications satisfy the substantially more stringent EPA II requirements (see C&I engine). In addition to compliance with the US legislation, the 50-Hz engines will continue to meet the German TA-Luft regulations. Due to the engines’ new combustion optimization, the nitrogen oxide levels have been brought to below 1700 mg per cubic meter and the particulate levels reduced to less than 50 mg per cubic meter. What is more, those figures are maintained across a power range from 50 to 100 % of rated output. The new ESCM (Engine Site Condition Management System) incorporated in the ADEC engine management automatically protects the engine if standard operating param are exceeded. To prevent thermal overload of the engine, its operating characteristics are adjusted according to factors such as ambient temperature and operating altitude. The engines are available in all cylinder configurations (V12, V16 and V20) with increased power output for even greater power density as well as emissions-optimized or fuel consumption-optimized versions, Table 1.
4 Rail Engine The new rail engines, Figure 8, are used to power railway locomotives, shunters and high-speed power cars. The demands in this application sector primarily relate to compact dimensions, high power-to-weight ratio and low fuel consumption. With a choice of V8, V12, V16 and V20 cylinder configurations, the engine offers a range of power outputs extending from 1000 to 3000 kW at 1800 rpm. That represents an increase of roughly 10 %. The engine achieves fuel consumption of under 200 g/
Figure 3: Modular design of the lead common-rail fuel injector
kWh while meeting the EU Level IIIA emission limits. They specify a substantial reduction in nitrogen oxide from the present upper limit of 9.5 g/kWh to a future maximum of 6.0 g/kWh as of 2009 for engines in this power class. The MTU rail engines achieve compliance with that NOX limit solely by internal engine design features by using the Miller process – in other words without resorting to exhaust aftertreatment. The inlet valves are closed at an earlier point in the combustion process than would normally be the case, resulting in lower combustion temperatures and consequently in lower nitrogen oxide emissions. The particulate emissions have also been substantially reduced by the new combustion param used for the Series 4000 rail engines. The V12 and V16 models of the engine are also available as US versions which comply with the EPA Tier 2 Rail (40 CFR 92) emission limits that apply in that market. As no exhaust aftertreatment systems have been needed to achieve the required emission limits, the required installation space has not increased compared with the previous model – which means that replacement within the available space in an existing locomotive is a straightforward operation. In combination with the higher power of the new MTU engines, the compact design produces an even better powerto-weight ratio. As a consquence, certain engine cylinder configurations still permit a four-axle locomotive design. MTU has also technically optimized the turbocharging system. The new Series 4000 rail engines are equipped with two of MTU’s own internally developed and produced turbochargers. They deliver higher turbocharger pressures of up to 4.5 bar and ensure constant engine power output from sea level up to an altitude of 1500 m. They are also capable of handling higher exhaust back-pressures, which means that, in the future, compact soot particulate filters can be fitted if necessary. The cooling systems on the MTU rail engines have also been modified. The twostage intercooling system now used incorMTZ 05I2007 Volume 68
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Table: Technical data Application
V8*, V12, V16, V20
V12, V16, V20
170 / 210
Cylinder capacity (l)
Mean pressure (bar)
Rated speed (rpm)
Max. output per cyl. (kW)
Max. engine output (kW)
Length x Height x Width (V20) mm
3680 x 2050 x 1590
3410 x 2050 x 1615
3335 x 1972 x 1562
4190 x 2075 x 1490
Power-to-weight ratio (V20) kW/kg
Fuel consumption (g/kWh) (optimum)
Miller combustion process Split-circuit cooling system
Special features * Rail only
C&I EPA engine
Emissions standard NOX (g/kWh) HC (g/kWh)
Genset EPA engine EPA Tier II 6.4
Rail EU IIIA, > 560 kW
Rail EPA 40 CFR 92
Marine EPA engine EPA Tier II 7.2
* ISO F cycle ** US locomotive cycle
porates a pre-cooling stage in which the charge air is initially cooled by the engine coolant followed by the actual intercooler stage, which further reduces the temperature of the intake air. As a result, more heat is removed at a higher temperature so that the locomotive cooling system can be made smaller. Consequently, weight and space can be saved on the locomotive.
5 Marine Engine The Series 4000 marine engines, Figure 9, are used both in commercial and military vessels. Yachts, ferries and patrol boats are typical examples of the type of application. A new addition to the range is the 20-cylinder version with a power output of 4300 kW at 2170 rpm. Thus the range of power ratings offered by the marine engines (V12, V16 and V20) now extends from 1920 to 4300 kW. The per-cylinder output has risen by around 26 %. The engine meets the EPA Tier II emission limits which primarily demand a substantial lowering of the nitrogen oxide levels. The limit of 7.2 g/kWh for NOX and HC emissions is comfortably satisfied by the MTU marine engines using only internal engine design features, in other words without resorting to exhaust aftertreatment measures. And de14
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spite reducing the emissions, a small reduction in fuel consumption was also achieved. The small overall dimensions and the increased power output result in a very compact design of the new MTU engines. Consequently they produce an even better power-to-weight ratio resulting in the best acceleration figures in its power class. MTU has also optimized the turbocharging systems on the marine engines. The new Series 4000 engines for marine applications are equipped with two (12 and 16 cylinder models) or four of MTU’s in-house developed, high-efficiency turbochargers that can be individually switched in and out of operation according to engine speed. The single-stage sequential turbocharging ensures optimum power over a very broad performance map of the engine and low fuel consumption. The engines are equipped with all the auxiliary systems and heat exchangers necessary for autonomous operation. The only equipment required to be provided on the part of the vessel are the appropriate interfaces for fuel, raw water, intake air and exhaust. Furthermore, a new safety system for crankcase monitoring is used for the first time. In addition to explosion relief valves it comprises complete monitoring of main bearing temperatures and big-end bearing temperatures (splash-oil sensors).
The new MTU Series 4000 marine diesel engines meet the classification society requirements for marine applications and comply with standards such as the SOLAS specifications relating to component surface temperatures of below 220 °C. These engines are also suitable for use in military vessels. For that, they fulfill the higher shock and acoustic requirements as well as those for the electromagnetic compatibility. They are also capable of operating under exaggerated list conditions.
6 Conclusion The improved Series 4000 benefits from the experience and the proven components of the preceding generations that have been in volume production for over ten years. In particular this has enabled optimization of emissions and performance figures. The design concept using a standardized basic engine offers enormous advantages in terms of logistics and economy. Consistent application of advanced project management and development methods meant that the first engines were delivered only three years from the start of the project. The new Series 4000 thus sets new standards in terms of economy, performance and environmental credentials. O