On Wednesday i visited the eCarTec 2010 Expo at the exhibition center in Munich Riem (http://www.ecartec.de/ ) by an invitation of the MINI E-Team.
Stand of BMW
At the stand of BMW there was MINI E # 046 and the Active E (the known concept vehicle, not one of the new vehicles for the future field test). As a traditional vehicle, an electrified BMW 1602 was shown.The car was used as a support vehicle during the Olympic Games 1972.
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| 8 of the 12 batteries in the former engine room of the 1602. The other 4 are located below. |
From the future MCV the drive train could be seen.
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| Batteries and drivetrain of the future MCV. |
Furthermore at the show a variety of chargers, plugs, etc. .. were shown, which i looked at not in detail i have to admire. The electrical power suppliers e.on and RWE in any case already stirred vigorous promotion for their new market ...
... and at Lotus they tried to give the electric drive the sound of a powerful gasoline engine. Not only unnecessary, but rather silly.
Another variant of a MINI with electric drive
I was most interested, however, in the eMini of the company AVL. It is a concept car with a serial hybrid drive.
In the serial hybrid drive, the vehicle drives solely with the electric motor. The on-board internal combustion engine drives a generator which recharges the battery or directly powers the electric motor. It is not mechanically connected to the drive train. This so-called range extender (REx) can be positioned anywhere in the vehicle.
In contrast to this in a parallel hybrid the combustion engine drives the drive axles via a conventional transmission. An electric motor supports the combustion engine and is able to move the car at low speeds. The battery is charged either by a separate generator driven by the combustion engine or by the electric motor driven through the gearbox from the combustion engine to run as a generator. Furthermore, the generator / electric motor can create power via regeneration by deceleration. Is the vehicle a "plug in", the battery can be charged additionally by the wall socket.
But back to AVL eMini, which Rex is also called "Pure Range Extender" due to the lack of mechanical connection to the drive train.
Interestingly, the Audi A1 e-tron uses exactly the same concept with identical specification.
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| Package of the AVL eMini |
The vehicle has a battery capacity of 12kWh (MINI E: 35kWh). Pure electric range of about 50 km should be possible. The electric engine has 75kW for short periods. This is exactly half of what the MINI E has available.
If necessary, a Wankel internal combustion engine charges the battery by a generator with an output of 15 kW. Due to this another 200km should be possible. Through the skillful arrangement of the components in the AVL eMini the back seat survived. Even the trunk has almost original size, except for a slightly raised ground.
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| AVL eMini |
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| Battery in typical T-arrangement. It uses the space of the exhaust system and the fuel tank. |
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This concept sounds very well, but there are some drawbacks.
The specified range of 50km electric + 200km by range extender can not be driven at once. Since the Range Extender provides much less energy for the battery than the engine cosumpts on higher speeds, after 50 + x km a break is needed. x depends from what point of the range extender will start loading and in which time the 50km are driven.
According to my conversation partner at the stand it takes the range extender about 2 hours to get a completely discharged battery to a SoC of 100%.
If the battery was completely empty, the output of the generator is only enough for a modest speed of 45 km/h. This is just acceptable in the city for urban driving, but not for highway driving.
A real range of 250km, which can be increased by simply gas refueling for another 200 km, can not be realized by the car.
For this a much more powerful range extender would be necessary which also may have a direct drive in the drive train for high speeds. This is a feature of the Volt/Ampera or the "Boosted Range Extender" by GETRAG. This solution blurs the boundaries between the parallel and serial hybrid. Since this detail of the mechanical connection of the combustion engine to the drive train in the Opel Ampera or Chevrolet Volt was revealed recently, there was discussion whether the Volt /Ampera is a pure electric vehicle or just an ordinary hybrid à la Toyota Prius. The fact is, that the Volt / Ampera can not drive solely with the internal combustion engine. (Link 1, Link 2)
... um ... back to Emini.
For me as a user the AVL eMini has no discernible benefits compared to the MINI E .
* For the short daily commute of a total of 20km a range extender is not necessary.
* The low battery capacity requires more frequent and more consistent charging on the socket to avoid the use of the Range Extender with its expensive fuel.
* A ride beyond the electrical range also requires careful planning, because the range increase by the Rex depends on several factors. Even if the Rex is allowed to run unattended during a planned break, this shall be possible under the open sky, but not in a garage or parking structure.
* A trip of 70 km highway is no problem for the MINI E. I'm not sure, whether the eMini manages this distance even with the REx started immediately.
However, the eMini has no limitations on space. In principle this is a possible "series" solution, whereas the MINI E was never intended as a series solution. And so the respectable battery capacity could be realized by rigorous elimination of the rear seat and a part of the trunk.
The REx module gives the eMini with the restrictions of the limited space available more flexibility than an for example 5kWh higher battery capacity, which could have been installed instead of the REx.
Other reasons in favor of the concept are:
* Space, cost and weight advantage by reducing battery size
* More "endurance" in traffic and traffic jam, when many electrical accessories are turned on
* Support of vehicle climate conditioning (for this vehicle not yet implemented)
* ...
Anyway, I'm excited about the experience made with the A1 e-tron. Therefore a small test fleet of 20 vehicles will be on Munich's roads in 2011.
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