Tognum presents hybrid drive system for trains

• Combined underfloor unit with diesel engine and electric motor for diesel railcars
• Board of Management member for technology Gerd-Michael Wolters: “innovative development for environmentally friendly train propulsion”
• Braking energy used for starting and in stop-and-go operation
• Reductions of up to 25% in fuel consumption and CO2 emissions
• Integrated exhaust-gas aftertreatment

Friedrichshafen/Berlin, September 24, 2008. At this year’s Innotrans rail exhibition in Berlin (September 23-28, 2008), the Tognum Group will unveil under the mtu brand its prototype of a new hybrid drive system for trains featuring exhaust-gas after treatment. It is based on the so-called PowerPack 6H 1800, an underfloor unit for diesel-powered local trains with a maximum power output of 390 kilowatts. This system stores the energy released while braking and uses it when the train starts and in stop-and-go operation. “With this hybrid drive for trains, mtu is once again demonstrating its leading innovative role with environmentally friendly drive system,” stated Tognum’s Board of Management member for technology, Gerd-Michael Wolters.

The functional principle is based on converting the kinetic energy released while braking into electrical energy and storing it with the use of a generator and brake energy recuperation. While starting and accelerating, the energy storage system releases the energy previously stored via a DC/AC convertor to the generator, which now drives the railcar like an electric motor. Depending on how much power is required by the train driver, the railcar is propelled either solely by electrical power or by a combination of diesel engine and electric motor. In railway stations or in urban areas, this technology allows trains to operate with low noise and low emissions. Hybrid drive is particularly economical on local transport routes with frequent braking and acceleration (stop and go), because this results in many charging and discharging cycles. As a result, fuel consumption and carbon-dioxide emissions can be reduced by up to 25%, depending on the route.

The engine/generator unit, with an electrical output of up to 400 kW, was jointly developed by mtu and a system partner. In addition, for the first time, the hybrid power pack includes SCR exhaust-gas after treatment with a urea tank; this is a prototype that fulfills the emission regulations applicable to Stage IIIB non-road diesel vehicles as of 2012. In this combination, the hybrid power pack is also suitable for the environmentally friendly motorization of existing diesel railcars.