08/16: Putting Power on the Road
The journey Bertha Benz and her two sons took from Mannheim to Pforzheim 128 years ago was not too comfortable. But it was innovative. Carl Benz’s invention to transmit the power of a combustion engine to three wheels laid the foundation for modern automobile drive technology. Today, drives are required to achieve much more than transporting persons from A to B: They must be comfortable, economical, ecologically compatible, and, in the future, even carbon-neutral.
The engineers at IPEK, KIT’s Institute of Product Engineering, develop test methods and systems for tomorrow’s drive trains and study the effects of changes in society’s acceptance of mobility on future transport concepts.
A drive train is composed of all the components that generate drive power in the vehicle and transmit the output to the road. In conventional internal combustion engine cars, these components typically are the engine and flywheel, clutch and transmission, differential gear, drive shafts or half axles, and the wheels. Most of these basic elements were also part of the three-wheeled Benz Patent Motor Car No. 3 which Bertha Benz used for her historic trip.
128 years of progress in mechanical and electrical engineering account for today’s highly complex drive trains. However, according to the experts at IPEK, these systems today still have great potential for optimization. Whereas Bertha Benz had only a single makeshift gearshift lever to control the brake, gas, and clutch, modern driver assistance systems are sophisticated and certainly ensure more safety and driving comfort. Since once-essential elements as the flywheel, clutch, and manual transmission can now be omitted, new drive trains, such as electric drives, present completely new challenges to engineers and technicians.
How will the drive for future sustainable mobility solutions ultimately shape the drive train of the future? Will it be a hybrid with a battery or an electric motor with a fuel cell? “We do not focus on any one solution which, in the end, may not be as sustainable as it may seem,” explains Sascha Ott, graduate engineer and director of IPEK and of KIT’s Mobility Systems Center. He goes on to point out that “a combustion engine, too, can be run sustainably if fueled with synthetic instead of fossil fuel.” Sascha Ott and his co-workers therefore study how existing engines, from gasoline engines to hybrid engines and electric drives or fuel cell drives, can be improved or combined in clever ways.
The researchers rely on the X-in-the-Loop Framework (XiL) developed at KIT. XiL enables testing and validation of individual components, such as the transmission or ECU code, or the entire vehicle. “X” stands for the test object to be investigated. The rest of the vehicle or realistic test tracks are then simulated on the computer. In this way, a conventional combustion engine combined with a novel transmission can be simulated virtually. Sascha Ott describes the innovative fuel-saving transmission: “Presently, we test a transmission which in particular situations, for example downhill, decouples automatically and turns the engine off. When the driver intervenes by accelerating, the system automatically couples without being noticed by the driver.”
Today’s test cycles, however, cannot measure and identify such fuel saving. “Since the current test cycles and licensing regulations do not represent reality, manufacturers providing such transmissions would have no advantage over those who don’t. Consequently, the transmissions are not being mounted,” says Sascha Ott. “Before the VW scandal, the discrepancy between reality and test cycle results did not bother too many people,” he adds. “Now we have the opportunity of changing things in such a way that drive trains that are more environment-friendly in real driving situations can be placed on the market.” Together with other institutes of KIT, universities, Fraunhofer institutes, and industry, the KIT researchers also test within the framework of the Regional Eco Mobility 2030 – REM 2030 innovation cluster. The driving performance of the fuel cell drive train with an improved electric motor developed by the project is analyzed based on a real road and driving profile from the area of Karlsruhe. “Of course, we are interested in the general parameters, such as performance, safety, environmental compatibility or sustainability,” says Sascha Ott. The REM 2030 project, however, is not only about the modern automobile, but addresses topics such as the use of information and communication technologies, mobility concepts, infrastructures, customer acceptance, and business models.
“We try to find out, for example, which technique will be accepted by the market eventually or, put differently, how acceptance of new systems can be created on the market.” This aspect of sociotechnology covers social standards such as the development of values and environmental awareness or the assessment of mobility demands. “We have the capability of finding answers to such questions not only for the German or European markets but also for the USA or Asia,” emphasizes Sascha Ott adding that “this skill makes KIT and its cooperating partners unique worldwide.”
After 1888, horses became obsolete and were replaced by automobiles. This was a drastic and far-reaching shift in values that fundamentally changed the world of mobility. Will autonomous zero-emission cars usher in the next individual-traffic revolution? Sascha Ott thinks that there is more to it than that and points out concepts that have become increasingly popular in big cities in recent years: Car or bike sharing, Segways, and well-planned walks which, combined with an efficient local public transport, provide the basis for intermodal mobility systems.
Equipped with a comprehensive means-of transport app, Bertha Benz today could comfortably combine walking, riding on a train and riding on a rented bicycle to get from Mannheim to Pforzheim in less than one hour. By car, without traffic jams, it would take her little more than one hour to reach her destination. Including diverse refueling stops, stops for refilling the coolant, and two quite unconventional repairs where she used her hatpin and garter, the 1888 trip in the Benz Patent Motor Car No. 3 took Bertha Benz 12 hours and 57 minutes.
Exzerpt auf Deutsch:
„Die Kraft auf die Straße bringen – Am Institut für Produktentwicklung werden Testmethoden und Systeme für Antriebsstränge entwickelt“
Übersetzung: Heidi Knierim
Ein Schwerpunkt der Antriebssystemforschung des IPEK - Institut für Produktentwicklung am KIT liegt in der Entwicklung innovativer Testmethoden und Systeme für Antriebsstränge von Personenkraftwagen. Die Wissenschaftler untersuchen zudem, wie sich die Akzeptanz der Gesellschaft in puncto Mobilität ändert und welche Konsequenzen dies auf zukünftige Transportkonzepte hat. Die in den 90-er Jahren von Ingenieuren des KIT entwickelte Validierungsumgebung „X-in-the-Loop“ ermöglicht es, einzelne Komponenten oder komplexe Antriebssysteme kostengünstig und effektiv zu testen, indem andere Teile des Fahrzeugs als Simulation hinzugeschaltet werden. Das spart Zeit und Kosten. Schnelle Datenverbindungen ermöglichen heute sogar ein „X-in-the-Distance-Loop“. Bei diesem Ansatz kommunizieren die zugeschalteten Simulationseinheiten des KIT in Echtzeit mit einem Bauteil in Stuttgart oder sogar am anderen Ende der Welt. Das senkt zum einen Transportkosten und erleichtert zum anderen die frühzeitige Validierung von Prototypen, die aus Gründen der Geheimhaltung das Werksgelände eines Automobilherstellers oder -zulieferers noch nicht verlassen dürfen.
Content within the current edition of the science magazine LookKIT on mobility at the Karlsruhe Institute of Technology, Edition 2/2016.
The text was written by Brigitte Stahl-Busse.
Foto: Martin Lober