MUTE -- Efficient city car, showcase for electromobility research

Sep 12, 2011
At the International Motor Show in Frankfurt, the Technische Universitaet Muenchen is rolling out the first publicly visible result of its research program TUM.Energy: a purely electric, energy-efficient city car that embodies and integrates research from 20 different university departments. Credit: Project MUTE / Copyright TU Muenchen

With its electric vehicle MUTE, the Technische Universitaet Muenchen (TUM, Germany) presents the first publicly visible result of its research program TUM.Energy. MUTE will showcase the TUM's answer to future challenges in personal mobility at the International Motor Show (IAA) in Frankfurt. MUTE is a purely electric, energy-efficient vehicle that meets all requirements of a full-fledged car. With MUTE, the 20 involved departments present a strategy for manufacturing a mass-production vehicle at an overall cost on par with that of comparable combustion engine vehicles.

With MUTE, researchers from the TU Muenchen have created an agile, sporty two-seater for regional . It has space sufficient for two persons plus luggage. The L7E certified electric motor, which is electronically limited to 15 kW, accelerates the light to 120 km/h. The lithium-ion battery is designed to guarantee a range of at least 100 kilometers. When needed, a zinc-air battery serves as a range extender – a "reserve" battery, as it were. Its sporty suspension and the active torque vectoring differential drive ensure good cornering stability and excellent driving performance.

The MUTE design conveys a snazzy, self-confident appearance. The built-in features fulfill all essential requirements of a modern road vehicle. A safety package, including an electronic stability program (ESP) system, a robust passenger compartment and crash elements made of carbon fiber reinforced plastic, imparts a high level of safety to the vehicle. Regarding ergonomics and comfort, here too, the MUTE concept leapfrogs other developments to date in the L7E class.

Decisive for the great efficiency of the MUTE is its low weight. A stable vehicle frame made of aluminum and a chassis made of carbon fiber reinforced plastic reduces the curb weight, including batteries, to a mere 500 kilograms. "Low weight is essential for an electric vehicle," says the TUM vehicle engineer Prof. Markus Lienkamp. "Greater weight requires more battery performance for the same range, which results in higher costs. Greater weight also results in reduced dynamics for a given power output. But we want a car that is affordable and fun to drive."

A further contribution to efficiency comes from the torque vectoring differential: A small electrical motor in the differential that functions both as a motor and as a generator serves to ideally distribute the forces between the two back tires. Especially when braking in curves, twice as much energy can be recovered as without the torque vectoring technology. At the same time, the advantageous distribution of drive and braking forces makes the car much more agile and also safer.

MUTE has been newly developed from scratch. Every part has been optimized for three main factors: efficiency, low overall cost and safety. Extensive preliminary studies were carried out to ascertain what mobility of the future will look like, what customer requirements will be decisive in purchasing decisions and how these might be fulfilled in a cost-effective and weight-saving manner. This led, among other things, to all tertiary user interface elements (e.g., for navigation and infotainment) being collected into a central touchpad. In addition, the touchpad computer can be used as a mobile interface for server-based, value-added services. This will allow the owner to check the current charging status using a smartphone. While underway, the most energy-efficient route (not only the shortest or fastest) can be determined based on the current traffic situation.

Over 200 staff members of 20 departments of TU Muenchen's Science Center for Electromobility joined forces to develop the MUTE concept. The research network belongs to the cross-faculty research initiative TUM.Energy, which bundles the extensive, long-term research activities of more than 100 departments in eight faculties on the topic of energy to a competence center with international prominence. The Science Center for Electromobility provides testing infrastructure, central test beds and the possibility for building shared prototypes. At the same time it is a docking station for national and international cooperation with research departments in industry and academia. The MUTE prototype was built with funding from the university budget and the Bavarian Research Foundation (BFS); project partners were C-CON, Gerg RPT and IAV. R&R KFZ did the vehicle construction. The TUM holds the intellectual property rights for overall concept. Over 30 partners from industry support the project as a whole.

Explore further: A platform to help consumers achieve sustainable energy consumption

More information: www.mute-automobile.de/

Provided by Technische Universitaet Muenchen

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Eikka
not rated yet Sep 13, 2011
If it's supposed to be a city car, then I wish it would be front wheel driven, because it's easier to handle that way. RWD cars tend to just plow ahead when you're trying to make a tight turn, and the lightness of the car doesn't help it get along when it's slippery.

With 15 kW (20½HP) it's not a sports monster anyways, so why bother having a rear wheel drive?
antialias_physorg
not rated yet Sep 13, 2011
RWD cars tend to just plow ahead when you're trying to make a tight turn, and the lightness of the car doesn't help it get along when it's slippery.

I do drive an extremely light RWD car (Smart Roadster, 800kg). and I have to say this is the easiest car to drive in a snowstorm I have ever been in. I can go (safely and at speed) where many others have to stop or have already slipped off the road. Since the motor is right above he rear wheel axle the weight distribution is perfect for difficult road conditions.

In the case of the MUTE either the electric motor or the battery pack would be in that place - so I expect it handles similarly (or better).
Eikka
not rated yet Sep 14, 2011
I do drive an extremely light RWD car (Smart Roadster, 800kg). and I have to say this is the easiest car to drive in a snowstorm I have ever been in.


No doubt about that, but my complaint was about handling in tight places like in the city, when it rains on cobblestone, or it's snowy and there's ice on the road, because RWD cars do tend to push when the front wheels are turned sideways. The car has to move forward before it will start turning, which can be problematic when parking etc.

FWD cars pull where you want it to go, so it's less problematic. Especially on hill starts, if you lack traction you can go zig-zag up the hill with ease where the RWD car would just spin wheels or slide backwards.
antialias_physorg
not rated yet Sep 15, 2011
FWD cars pull where you want it to go, so it's less problematic.

Actually I find them more problematic because FWD cars have to put the forces for steering AND acceleration on the forward wheels.

The maximum force you can impart on the road is determined by:
- road condition
- acceleration forces (in line with your axis of travel)
- steering forces (transversal to your axis of travel)

The latter two are at right angles to another. If you want to represent them graphically you can show that the maximum allowable force vector has to remain inside a circle with the x-Axis denoting transversal steering forces, the y-Axis acceleration forces and the radius of the circle determined by road conditions

This means that if you steer more then you can put less acceleration force on the same patch of road before slipping

This also goes for RWD - but not as much as for FWD cars where all forces are concentrated on half the area.

Theres a reason why all race cars have RWD.