At Innotrans in Berlin, Rolls-Royce Power Systems’ MTU brand introduced the new MTU EnergyPack battery system for rail as a product that is now available for ordering. The Hybrid PowerPack is a market-ready advanced development based on a test version that has demonstrated its reliability in an intensive test program consisting, among other things, of test runs covering no less than 15,000 km.
The Hybrid PowerPack combines a diesel engine with an electric machine, which can be used either as an electric motor or generator, and the MTU EnergyPack battery system, which stores the energy recovered during braking. The battery system has been significantly improved by MTU engineers since the completion of the trials with the hybrid test vehicle.
With hybrid drives, braking energy is converted into electrical energy and stored in the battery. This energy can then be reused later as a boost on gradients or to accelerate. As a result, up to 25% of the diesel fuel can be saved. Hybrid technology is especially efficient for use on local lines where braking and acceleration in stop-go mode is frequent, and much of the braking energy can be recovered. In this case, the hybrid drive is amortized after just a few years.
If during periods of low load factors the diesel engine is operated at a more favorable energetic operating point or switched off entirely, emissions can be reduced substantially: per kilometer, up to 230 grams less CO2 and up to 0.92 grams less NOx compared with conventional systems.
With a combined diesel and electric drive, the train accelerates even better. When it comes to keeping tightly calculated schedules or catching up on delays, the electric motor provides additional torque. This means that the railcar can travel uphill faster or reach the target speed quicker. For example, the time for a 72km route can be shortened by more than five minutes.
The electric motor can be used as the main drive when rail vehicles need to be operated as quietly as possible: For example, during travel through residential areas and tunnels or while stopped at a railway station. The noise level when stationary can be reduced by up to 21 decibels.
The MTU EnergyPack, which was developed in cooperation with a development partner, consists of 180 individual Li-ion cells, has a capacity of 30.6 kWh and weighs 350 kilograms. To meet the wide range of customer requirements, multiple EnergyPacks can be connected. MTU guarantees a service life of 28,000 hours for the rail-certified battery system, which is equivalent to a useful life of some eight years. MTU EnergyPacks can be installed in different areas of the vehicle, in the roof, for example, or the underfloor area of a railcar.
As a result of this flexibility in terms of installation options and the compact design of the Hybrid PowerPack, it is suited both for newly developed vehicles and for repowering existing vehicles. When used in conjunction with a pantograph (current collector), the Hybrid PowerPack can also be used as a trimodal propulsion system, since the electric drive system already incorporates an electric motor. This provides operators with further application possibilities and can also ensure that the value of the vehicle is maintained in the event that routes are electrified.
We are proud that, after many years of pioneering work, we are now able to offer the railway market a mature product that meets all required railway standards and provides the customer with numerous benefits: using this drive system, operators will be able to achieve fuel savings of up to 25 per cent, while enjoying a significant reduction in exhaust and noise emissions. Furthermore, the integrated electric machine provides increased acceleration and the possibility of making up for delays.—Bernd Krüper, Vice President Industrial Business at MTU
The Hybrid PowerPack is version of the MTU PowerPack that has been operating successfully now for 20 years: these are compact drive systems, which, in addition to the engine and power transmission system, include all the ancillary systems required to operate the vehicle, such as the cooling system and exhaust gas aftertreatment system. MTU developed this concept 20 years ago and was the first company to do so worldwide. Since then, it has delivered over 6,000 PowerPacks to rail customers around the globe.