High-tech on the Water: The New mtu 2000 Common Rail Marine Engines

Posted on September 08, 2004

The new mtu 2000 Common Rail marine engines set new standards for marine engines in their power output category.
  • Intelligent engine concept
  • Common rail injection system with accumulator injectors
  • New, powerful turbocharger system
  • New "ADEC" (Advanced Diesel Engine Control)engine electronics

The new mtu 2000 Common Rail marine engines set new standards for marine engines in their power output category. By using state-of-the-art technologies, they are smaller, lighter, cleaner, more powerful and more economical than their predecessors, the 2000 series. The basic concept as well as the key technologies of turbocharging, injection and electronics have been redeveloped and advanced. The 2000 Common Rail series takes its name from the use of the common rail system.

Intelligent Engine Concept

The 2000 Common Rail engines have a very low power-to-weight-ratio (1.99 kg/kW – 1.48 kg/HP). Features including an increased power per cylinder and the extensive use of light alloy made this possible. The weight optimization of components and the modular design of the engine are also important factors. In several places in the 2000 Common Rail engines, more than one function is integrated into the same component. This reduces weight and saves space. One example of this is the engine Vee, which together with the outer wall of the charge air cooler situated above it forms the ducting for the charge air flow, which goes from the turbochargers to the charge air cooler. Such a design was possible because a common rail injection system is used, and the space in the engine Vee (90 degrees) is therefore not occupied by injection pumps.

As a result of the cleared engine Vee, the crankcase was also redesigned. For example, the water feed and return channels arranged in the V angle were designed as box-shaped components that reinforce the cylinder walls and support the banks against each other. This stabilizes the cylinder banks and reduces cylinder liner deformation, and therefore piston ring and cylinder liner wear.

Common Rail Injection System with Accumulator Injectors

mtu has been using the powerful common rail injection system in its engines with great success since 1996. This technology has now become the standard in the automotive sector, and was recently also brought into use by competitors in the off-highway sector. As a result of our positive experience with this system, mtu has again used a common rail system in the 2000 Common Rail. However, it is an advanced version, in which an accumulator is mounted on top of the injectors.

The actual storage function is therefore no longer performed, as previously, by the common rail, but by individual storage facilities in the cylinder heads. This prevents pressure fluctuations in the fuel line, thus stopping surging at the injectors and the supply of too little or too much fuel. The pressure (max. 1800 bar) remains virtually constant in the entire system. In addition, the fuel lines have a smaller and, in the standard version, single-wall design. The fuel line is situated inside the charge air pipe, and is thus surrounded by a second layer.

The fuel injection system of the 2000 Common Rail series is fitted with various safety devices. A pressure relief valve in the distributor reduces the maximum system pressure when required, thus protecting the other high-pressure components against overload. With the lower system pressure, the engine can be operated safely under partial load until serviced at the next opportunity.

The injectors are actuated by 2/2-way valves, which are activated by the engine electronics. The control voltage here is up to 42 volts. The control valve was positioned very close to the nozzle needle so that there are only slight delays between the opening of the valves and the nozzle needle. This design therefore has the potential for multiple injection without any design changes having to be made to the control unit.

New, Powerful Turbocharger System

The 2000 Common Rail engines are fitted with a powerful turbocharger system, in which two (in the 8V and 10V versions) and three turbochargers (in the 12V and 16V versions) are used. Only one charger runs at low engine speeds; the second and third charger are only engaged electronically at higher engine speeds. This sequential turbocharging ensures a powerful charge air flow and therefore an immediate and strong engine acceleration response across the entire performance map. The efficiency of the turbocharging system is enhanced by the integration of the charge air cooler into the engine Vee, as this shortens the path of the charge air flow.

The ZR 125 turbochargers were developed in-house by mtu, and are also manufactured internally by the company. At a maximum engine speed of 85,000 rpm, they build up a maximum charge air pressure of four bars, a pressure that is otherwise only achieved by complex two-stage charging systems in engines of this size. The compressor wheel is made of aluminum, which has a positive impact on the acceleration performance of the turbochargers because of the low weight. The compressor wheels of the turbochargers are housed in a water-cooled carrier housing, which keeps the surface temperatures below the level of 220 degrees Celsius stipulated by the SOLAS regulation (Safety of Life at Sea).

New "ADEC" (Advanced Diesel Engine Control) Engine Electronics

Another major innovation in the 2000 Common Rail series is the new generation of mtu's own "ADEC" (Advanced Diesel Engine Control) electronic engine management system. During the development of the units, the diesel engine was regarded from the outset as an integral component of the propulsion system. Consequently, the engine can be easily integrated into the power train. To achieve this, in addition to the engine controller, a system interface was developed, which provides shipbuilders with a wide range of capabilities and advantages. The controller was given a far more robust structure than previous units, with the result that it is even more suited to the tough conditions in the engine.

During the development of the engine management system, an easily programmable system interface and a flexibly usable functionality were integrated into the system interface. The engine controller now contains far fewer customer- and system interface-specific settings than the predecessor model. The variants for the different applications are supplied via the system interface. The use of a commercially available compact flash card in the system interface means that the system interface is easy to program.

An Ethernet interface enables remote diagnosis of the engine management system via the Internet, and makes optimized fleet management possible, as different engine and system data can also be read out via remote access. However, an innovative data storage and troubleshooting concept also makes handling easier in service scenarios. An update is generated automatically via the system interface. If the engine controller has to be replaced at any time, the data of the engine management system, for example engine settings, engine operating hours and other "service life" data of the engine, is copied to a new engine controller, without the need for an additional service tool.

Number of cylinders 8, 10, 12 and 16
Engine output for yachts and fast ships (depending on the cylinder variant) 895, 1120, 1344, 1792 kW /1200, 1500, 1800, 2400 HP
Power per cylinder 112 kW (150 HP)
V angle 90 degrees
Bore/stroke 135 mm/ 156 mm
Displacement per cylinder 2.23 liters
Idling speed 600 rpm
Maximum engine speed 2450 rpm
Turbocharging Single-stage sequential turbocharging with two or three turbochargers, charge air cooling, water-cooled compressor wheels
Injection Common rail with individual storage volumes integrated into the injectors
Cooling system Mixed circuit
Valve control Four valve design with a centrally arranged camshaft
Cylinder cut-out system Optional, electronically controlled