“DE4LoRa”: TU Darmstadt is researching an 800-volt hybrid vehicle

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Research teams from the TU Darmstadt, together with industrial partners, are developing a drive for a hybrid vehicle consisting of two electric motors and a natural gas engine with minimized emissions. The project under the project called “DE4LORA” is funded at around 6.4 million by the Federal Ministry of Economics and Energy (BMWi), the entire project volume is around ten million euros. Thus, the BMWI wants to promote the development of more efficient and environmentally friendly mobility.

Future vehicles should be laspy and affordable – this can be implemented with a variety of drives. The TU Darmstadt has been researching new solutions and drives, including the project called “De4lora“. It stands for “Double E-Drive for Long Range” and contains a prototypical drive concept with an electric drive that can reach high ranges through additional hybridization. The novel drive concept is to be tested after successful test stand tests under real-time conditions in two experimental vehicles. Unfortunately, there are no pictures of the vehicle yet, but the research teams promise “a coherent overall concept with maximum efficiency”: “For many users whose daily journeys rarely exceed 100 kilometers, high-voltage hybrids are a sustainable solution,” says professor dr.-engineer. Stephan Rinderknecht, specialist for mechatronic systems in mechanical engineering at the TU Darmstadt and one of the initiators of “DE4LoRa”. He goes on to say: “They offer locally emission-free electric driving on everyday routes and at the same time full long-distance suitability. We develop and test the technical basis in the form of a new reference architecture with DE4LoRa.”

Development of a new approach for hybrids

For many users whose daily journeys rarely exceed 100 kilometers, high-voltage hybrids should represent a sustainable solution. High-voltage hybrids, such as the popular plug-in hybrids, have so far mainly been found in the upper price segment, because simply adding an electric drive to the conventional one makes the vehicles relatively expensive. Purely battery-electric drives have established themselves as an alternative. Longer distances are also possible when using very large battery capacities. For many usage profiles and boundary conditions, potential for further minimizing the overall ecological footprint remains open for both concepts. This is where “DE4LoRa” comes in: The drive concept combines the goals of high efficiency with low costs and a long range thanks to the simple structure of the hybrid double electric drive. The drives are connected via a special transmission concept that can be classified as a so-called Dedicated Range-Extender Transmission (DRT).

On the basis of a voltage of 800 volts, a fully-fledged, highly efficient electric drive is implemented. This begins with a charging process for which a bidirectional charging system is being developed that is intended to reduce charging losses to a minimum. A bulky transformer in the vehicle can be dispensed with without compromising on electrical safety. Electric driving is also designed to minimize losses thanks to the multi-speed drive train and two identical electric motors. According to the company, they take advantage of the fact that a small electric motor that is used to a higher capacity can be more efficient than a large machine (downsizing effect).

Depending on the load requirement and speed, “DE4LoRa” gives you the freedom to use either just one e-machine (for lower power) or both with a total of four different gear ratios. The majority of everyday journeys are fully electric with a moderate battery capacity. Since the internal combustion engine has four parallel corridors and can be used serially, the concept is despite – compared to battery-electric vehicles – low battery capacity through its hybridization long-distance suitable.

Design of a pure natural gas engine

For this purpose, the researchers are designing a pure natural gas engine (operated with Compressed Natural Gas, CNG), which, due to its type, is characterized by lower greenhouse gas emissions than, for example, a classic gasoline engine and is more efficient than a dual-fuel CNG engine that can process both natural gas and gasoline got to. Through intelligent use of the two e-machines, the “DE4LoRa” gas engine does not have to follow all dynamic changes and can therefore run more often in highly efficient and low-emission operating ranges – in a so-called “phlegmatized” operation. This saves further fuel, enables a less complex structure and smaller dimensions, which reduces costs. If synthetic gases produced on a regenerative basis are used in the future, the drive can also be used CO2-neutrally over long distances.

With around 2.7 million euros in funding, the TU Darmstadt is the largest partner in the research project and, with two institutes each, Department of Mechanical Engineering (Institute for Mechatronic Systems and Institute for Internal Combustion Engines and Vehicle Drives) and the Department of Electrical Engineering and Information Technology (Institute for Electrical Energy Conversion and Institute for Power Electronics and Drive Control). The management of the current project is in the hands of the network coordinator Vitesco Technologies. The company is also one of the eight specialist industrial partners. Other industrial partners are APS-technology GmbH, AVL Software and Functions GmbH, BMZ Germany GmbH, COMPREDICT GmbH, Hyundai Motor Europe Technical Center GmbH, Isar Getriebetechnik GmbH & Co. KG and Windschiegl Maschinenbau GmbH.

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7 thoughts on ““DE4LoRa”: TU Darmstadt is researching an 800-volt hybrid vehicle”

  1. What the hell did I read there?! This text is from 1990?
    “For many users whose daily journeys rarely exceed 100 kilometers, high-voltage hybrids are a sustainable solution”
    There are already efficient and inexpensive BEV solutions for this, if they haven’t gotten it yet? Or is it just about tapping taxpayers’ money?

  2. A rather small battery and a range extender (REX) is probably a sensible approach for vehicles that usually have to be able to drive short distances, but also long distances in between. Definitely better than having to carry a much too large battery with you all the time just in case
    Whether it makes sense to continue researching a natural gas REX today is another question. You can also use hydrogen straight away, which you can either convert directly into electricity in a fuel cell or burn in a combustion engine or gas turbine.

  3. this has nothing to do with research.
    This inflationary use of the word research is frightening.

    Researching something means I try various things in various combinations to see what comes out of it. What is being done here is to achieve a given goal by trying out the given materials…

    what a crap and waste of tax money

  4. For a “gear fetishist” on the “100 km level” of the caliber of a Mr. Rinderknecht, the combination of 3 engines with several gears and various. gangs yes be a dream … and if it is then funded from taxes .. 🙁

    In contrast to the simple/robust/durable concept – as the BEV is – a 2-drive hybrid with div. Clutch and gearbox tralalla a far too high cost, inspection and maintenance effort!

  5. Good night. The few users whose daily trips exceed 100 km could buy a used e-up for 16.000 € buy as long as it does not have the ID.3 Pure there, after promotion 20.costs €000. Or later ID.1 and ID.2. With all the cars mentioned, you can easily drive down over 100 km in winter at -10° and against a headwind without wasting fossil fuels.

  6. The natural gas lobby found a politician with a subsidy pot to distract people from BEVs.

    Natural gas generates CO2 when it is burned, or if it is generated as a synthetic gas with green electricity, then it needs around three times the amount of PV and/or wind power plants.

    We must be happy if we can generate enough green electricity here and around the world for all BEVs and for the many houses and factories. Synthetic fuels will have to remain the exception.

  7. The fact that research is still being done on drive concepts that use fossil fuels is a waste of taxpayers’ money. I don’t know what the German government didn’t understand about the need to phase out fossil fuel combustion as quickly as possible?


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