Enhancing energy efficiency in rail vehicles.

Sustainability is an increasingly important factor for maintaining competitive edge. Innovative technologies by Knorr-Bremse are helping to make rail transportation even quieter and more efficient. For many years now, the Group has invested significantly more in sustainability strategies than required by law or its customers.

Energy efficiency is already a key driver of competitiveness today, and its importance will continue to grow in years to come. “Knorr-Bremse is a technology pioneer whose many innovations make an important contribution to climate protection and the conservation of our natural resources,” says Klaus Deller, Chairman of the Executive Board and Executive Board member responsible for Rail Vehicle Systems. He adds that Knorr-Bremse is raising awareness of the importance of more efficient and sustainable processes among its partners and suppliers. In addition to energy saving Rail Vehicle Systems is already focusing its product development operations on noise reduction.

Good news for trackside residents: whisper brakes reduce noise

People who live near freight train routes are calling for a reduction in noise pollution. The main source of noise is the rumble of the trains’ rolling noise, which is largely caused by gray cast iron brake blocks grating against the surface of the wheels. The resulting surface irregularities cause vibrations in the wheel-track system, and this in turn generates noise. Brake blocks made from organic materials can reduce this noise by up to 10 dB(A), which is perceived by the human ear as a halving of the noise level. Knorr-Bremse is making an important contribution in this area with its “whisper brake” LL brake blocks for the aftermarket and K-blocks for new vehicles. Knorr-Bremse now produces its own friction materials for the majority of applications. In Germany alone, DB Cargo is aiming to convert its fleet of approximately 55,000 freight cars to LL composite brake blocks by 2020. For some years now, it has been compulsory for new vehicles in the EU to be fitted with organic brake blocks.

Silencers cut suburban train noise

Reducing noise emissions is also important in the Air Supply business. The challenge is to find a solution to the conflict between this goal and the requirements of air supply systems’ compressors and air dryers. The simplest way of significantly reducing all noise emissions would be to fully encapsulate the systems. However, cooling air vents are absolutely indispensable. Knorr-Bremse employs the latest simulation techniques and a special acoustic chamber to find the optimal solution. The improvements that this can deliver are demonstrated by the VV120-T noise-optimized oil-free compressor developed for S-Bahn trains in Frankfurt and Stuttgart. Special silencers reduce the blow-off noise sound pressure level by up to 20 dB(A).

Lower weight for lower energy consumption

Because they constantly have to accelerate and brake, weight is particularly important for metro trains. Knorr-Bremse’s aluminum-ceramic composite cast brake discs provide a special energy-saving solution for this application. The Hong Kong metro, for example, has opted for the aluminum discs on their new trains. They make each car up to 400 kg lighter compared to conventional gray cast iron discs. In fact, the aluminum brake discs’ lower weight has a dual benefit. They are fitted directly on top of the axles, meaning that less energy is required for angular acceleration.

Less wear, lower environmental impact

Although aluminum discs are more expensive to purchase than their conventional counterparts, their service life is at least three times longer. A further advantage is that aluminum discs reduce brake pad wear, resulting in a lower environmental impact from abrasion particles. “The Hong Kong brake discs are tailored to the new metro vehicles and their operational profile,” says Dr. Nicolas Lange, member of the Management Board for Rail Vehicle Systems. The manufacturing process for the aluminum discs is far more complex than for gray cast iron discs and requires extensive know-how. Lange believes that they have huge potential for the future: “The number of orders and inquiries has been growing strongly for several years.”

Train doors deliver energy savings and improved acoustic insulation

IFE’s Generation 4 entrance systems constitute a major advance over previous generations. Their lighter, smaller and yet at the same time stronger components deliver a weight saving of approximately 20 percent. Although regional multiple units account for most of the demand for Generation 4 doors, they can also be installed on light rail vehicles and metros. Moreover, the enhanced door leaf insulation reduces heat transfer by 50 percent, helping to cut the amount of energy used for air conditioning. IFE has also achieved a threefold improvement in the door systems’ acoustic insulation. Last but not least, the FLEX door control unit now uses less electricity.

Aluminum composite cast brake discs enable weight savings of up to 400 kg per metro car. However, this material is much more complex to process than gray cast iron.
Knorr-Bremse is a technology pioneer whose many innovations make an important contribution to climate protection and the conservation of our natural resources.

“Smart train” provides optimized driving recommendations

The iCOM Assist app for the iCOM digital platform provides highly specific recommendations via a small monitor on the driver’s desk. To make this possible, information about the train, route and timetable, as well as current position and speed, is fed into the system. “The system uses this information to make optimized driving recommendations – for instance, the exact point from which the train can roll on to the next scheduled stop and still arrive on time. This saves energy and reduces wear and tear,” says member of the Knorr-Bremse Management Board Mark Cleobury, pointing out that iCOM Assist isn’t a substitute for the drivers’ experience, it simply optimizes their performance. The system does not require a license and can be easily retrofitted.

Intelligent HVAC systems

Knorr-Bremse’s state-of-the-art HVAC systems also help to save energy. If necessary, they can reverse the cooling cycle and draw warmth from the outside air to heat the vehicle. This can reduce energy consumption by up to 32 MWh per rail car per year. This efficient technology is particularly effective in cooler parts of the world. In addition, it uses recuperated brake energy and flexibly adjusts its output, for example when passenger numbers are low. Intelligent design and lighter components make the new Knorr-Bremse HVAC systems approximately 400 kg lighter, contributing to further reductions in CO₂ emissions.

Sustainable supply chain

Knorr-Bremse provides the customers and partners of both divisions with proactive support to strengthen sustainability across the entire supply chain. A new Supplier Code of Conduct aims to ensure that the same environmental and social standards are observed all over the world. As a member of Railsponsible, an initiative of manufacturers and operators including DB, SNCF, Alstom and Bombardier, Knorr-Bremse leads the way in sustainability for the rail sector.

iCOM provides open applications, allowing customers to run the individual apps on their own devices. Shown here, the iCOM Assist energy-efficient driving app.

Guaranteed safety, even in Siberia: IFE uses its own climatic chamber to test its doors down to temperatures of -50°C.

Effective insulation: Generation 4 door leaves reduce heat transfer by around 50 percent, helping to save energy.

If necessary, Knorr-Bremse’s state-of-the-art HVAC systems can reverse the cooling cycle and draw warmth from the outside air to heat the vehicle. They also adjust their operation to current requirements. If passenger numbers are low, they reduce their output accordingly.

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