Our environment is changing. E³ is Plasser & Theurer’s answer to it. The innovative technology of the HTW 100 E³ hybrid motor tower car was put to the test in the Climate Wind Tunnel.
It is a fictitious scenario and nature fortunately spares us from it: Enjoyable late summer temperatures of +20 °C during the day, dramatic temperature drop during the night. All of a sudden, the temperature falls to -5 °C, then even to polar -30 °C. Another 24 hours later, winter coat, woollen cap and gloves are no longer needed. Figuratively speaking, it’s straight from Siberia to the desert where temperatures reach +50 °C. This is the ultimate endurance test for every machine.
The revolutionary Plasser & Theurer machine, the HTW 100 E³, passed the test in the Climate Wind Tunnel of Rail Tec Arsenal (RTA) with distinction. “There were two reasons for the climate test: To test the new battery technology, and to examine the theoretical values of our suppliers,” explains Christian Weitersberger, responsible Head of Engineering, Plasser & Theurer.
The heart of the HTW 100 E³ is the innovative battery system. It allows the machine to work fully electrically on the work site and makes it emission-free and quiet. Particularly in urban environments or tunnels, this is a great benefit. The battery capacity lasts for two six-hour shifts. The operating temperature is crucial for the batteries’ service life.
Most of us will know how it feels when you want to use your mobile phone on a cold winter’s day, but find yourself staring only at a black screen. Even though, just minutes ago, the battery seemed to have enough energy. A problem of modern everyday life. Since 1953, Plasser & Theurer has been synonymous with reliability, efficiency and pioneering spirit. In collaboration with Kreisel Electric, an expert in electromobility, a sophisticated thermal management system was developed for the HTW 100 E³.
The secret behind thermal management
At a cell temperature of between -20 °C and +40 °C it is ensured that the batteries generate energy. The optimum operating temperature is between +25 °C and +35 °C. Siegfried Anschuber, Software Developer at Kreisel Electric, explains the system: “The nine batteries are fitted with more than 200 sensors that measure the temperature constantly.
The new thermal management allows maintaining a permissible operating temperature by warming or cooling the batteries. As a result, external conditions barely affect us anymore. And: When a machine is parked at -20 °C, the next day, the batteries are heated up via the heat pump.” During testing in the Climate Wind Tunnel, these temperature limits were simulated and numerous machine functions were tested, ranging from the windscreen heating to the cabin door. The computer recorded any even minor change in temperature or humidity and any performance and pressure curve live via specially installed measuring sensors. It was even snowing and the sun was shining at the push of a button Vienna’s 21st district.
“RTA, the operator of the Climate Wind Tunnel in Vienna, offers the possibility to examine the effect the weather has on machines and components under realistic conditions. Different temperatures and diverse forms of precipitation can be generated and wind speed simulates travelling speeds,” Andreas Rosenkranz, Project Manager at RTA explains. The facility had been designed for rail vehicles. “The chassis dynamometer makes it possible to actually operate the test object.”
“The machine has to hit the ground running”
A heating mat and humidifier were used to simulate the heat and moisture release of the human body in the cabin, illustrating the attention to detail. The HTW 100 E³, Weitersberger explains, was fundamentally designed for extreme conditions. However: “It is not unusual, that overhead line machines are not operated for two or three weeks. During this time they are often parked outside at sub-zero temperatures. When there is a problem in the overhead line system, the machine must hit the ground running.”
Therefore, testing has been important to collect the information required to draw conclusions: How long does preheating take using a diesel-powered heating device at a temperature of -30 °C? What level of energy output is required to allow the individual components to run at full performance? To find out, the HTW 100 E³ was equipped with more than 20 sensors prior to testing. It took three days to prepare the machine, and four days to simulate the predefined scenarios.
“Thanks to the different temperatures, we could find out, whether or not condensate forms in the electronics cabinets,” Weitersberger explains. “We aim to provide our customers with operational data that meets the needs of practical operation even more precisely. We will include the results into our documentation.” Even though nature might spare us from changes of 80 °C, the HTW 100 E³ works under extreme conditions. It has passed the ultimate endurance test.