BMW i3 and i8 concepts feature new LifeDrive platform
These are the BMW i3 and the i8 Concepts, the two members of the new BMW i family that BMW previewed last week at Messe Frankfurt. The BMW i3 was originally known as the BMW Megacity Vehicle, and it will be BMW’s first series-produced all-electric vehicle, and you’ll see the i8 sports car in the upcoming Mission Impossible movie.
BMW started off the BMW M sub brand for high performance versions of its cars. The company had to evolve with times, and with the rise of the popularity of the SUV came the BMW X brand along with xDrive.
Now as the world continues to change with the times and the idea of mobility continues to evolve – BMW has responded with the creation of a sub-brand which meets the changing needs of customers head-on: BMW i. BMW i is all visionary vehicles and mobility services, inspiring design, and a new understanding of premium that is strongly defined by sustainability.
“The purpose-oriented and sustainable mobility solutions from BMW i mark the dawn of a new era in personal mobility for the automotive industry,” said Ian Robertson, member of the Board of Management of BMW AG responsible for Sales and Marketing.
The BMW i brand started off as a think tank called project i back in 2007. BMW had set project i up to explore sustainable mobility solutions, intended to generate a transfer of expertise into both the company as a whole, as well as future vehicle projects.
Quite interestingly, the sustainability goals extended way beyond just the vehicles themselves. The development engineers focused on the entire value chain – not just the end result products. Every parts-related process, technology, supplier – they’ve all been required to contribute to the sustainability rating of the products. The goal is to reduce resources consumption and emissions per vehicle produced by 30 per cent over 2006 levels by 2012.
Anyway, let’s look at the two concept cars. First up – the BMW i3 concept, previously known as the BMW Megacity Vehicle. It is the BMW Group’s first all-electric car intended for series production, focused on the mobility challenges of ultra urban areas. BMW is not the first to the end of the line in the race to start selling a production EV – there are already other cars on sale such as the Nissan LEAF, but this is a premium EV.
It kinda looks like a typical hatchback, and you can even imagine perhaps that space in front of the passenger cell where the combustion engine might be in a conventional car might house the i3′s electric motor.
But the i3 (and the i8) are not “conversion” cars. Their chassis architecture was built from ground up to house an electric drive train. While in a combustion engine car it might make sense for the engine to be up front with the gearbox, the petrol tank at the rear and etc, this might not be the best way to house the components necessary for an electric drive.
Electric drive components place totally different demands on a vehicle when it comes to installation space and cannot be integrated into that vehicle without adding weight and compromising interior and boot space.
Because of a chassis designed for a combustion engine, many of these “conversion EVs” have lots of restrictions and compromises because of the legacy architecture they are based on, and sometimes the cars end up having an odd weight distribution, or a very heavy weight. The MINI E is an example of a conversion electric car – a regular MINI chassis converted to use batteries. BMW says the i3 is much lighter than the MINI E because it was designed from ground up as an electric car. The 1-Series was also ‘converted’ into the BMW ActiveE Concept.
Enter BMW’s LifeDrive architecture, which is built from ground up for electric car construction. It’s divided into two parts – the Life module which contains the ‘life’ or the passengers, and the Drive module which contains the drive equipment like the engine, electric motor and batteries. These modules are said to be separate, independent functional units.
The Drive module houses the vehicle’s suspension, battery, drive system, and structural and crash functions into a construction made mainly from aluminum. The secure arrangement of the battery in the Drive module gives the vehicle a very low centre of gravity and optimum weight distribution.
The passengers sit in the Life module, consisting of a high-strength and extremely lightweight passenger cell made from carbon fibre-reinforced plastic (CFRP). The use of CFRP ensures the Life module is remarkably light, helping counter the weight of the other components, thus helping achieve better range and power.
You might worry about the idea of something that has the word “plastic” on it surrounding you and protecting you on the highway. Like the cockpit of a F1 car, the CFRP passenger cell provides an extremely strong survival area. While regular metal chassis constructions require the addition of large energy absorption zones, special deformation elements in the CFRP structure allow large amounts of energy to be absorbed in an amazingly small area.
With the drive components located in the Drive module, there is no centre tunnel running through the passenger compartment. This allows, if necessary, the left and right seats in a row to be connected with each other by a continuous seat surface, which allows for a relatively more comfortable entry and exit via the front passenger side of the car and means you can park one side of your car up close to walls, for example.
All of this sounds very high tech but it actually kinda reminds me of the old way of constructing cars – body on frame instead of unibody, a technique still used today in most pick-up trucks.
Although both the i3 and the i8 are based on the LifeDrive architecture, the geometric implementation of the concept differs in the two models, having been adapted to suit their different usages. The BMW i3 Concept features a horizontal-split variant of the LifeDrive platform optimised to accommodate the car’s electric drive system.
Here, the Life module is simply mounted on top of the Drive module. The 170hp/250Nm compact (smaller than a typical internal combustion engine, and 40% smaller than the MINI E’s motor) motor is mounted at the rear axle, while the rest of the space in the Life module contains a large battery to provide the electric-only i3 Concept a longer range. The battery is penned in by aluminium profiles, which protect it from external impacts. Crash-active structures in front and behind it provide the necessary energy absorption in the event of a front- or rear-end collision.
An integrated liquid cooling system keeps the battery at its optimal operating temperature at all times, which helps to significantly boost the performance and life expectancy of the cells. The climate/heating system cools the fluid circulating in the battery housing via a heat exchanger. Because the cooling system of an electric car is different, there’s really no need for a radiator grille at the front, so to improve aerodynamics, the i3 is designed with no air vents at the front – the kidney grille is decorative.
The battery can be fully recharged in six hours at a standard power socket. If a high-speed charger is used, an 80 per cent charge can be achieved in just one hour. The i3′s electric motor via a single speed transmission gearbox takes it from 0 to 60km/h in under 4 seconds. It hits 100km/h in about 8 seconds. It hits an electronically governed top speed of 150km/h.
If necessary, BMW has designed for the i3′s LifeDrive platform to be able to accommodate a small petrol engine as a range extender. This range extender (REx) engine will be integrated together with the electric motor in the rear axle.
The BMW i3 Concept also has a high recycled material content. 25 per cent of the interior plastics by weight have been replaced by recycled and renewable materials, as have 25 per cent by weight of the exterior thermoplastic components, while the CFRP used in the Life Module consists of 10 per cent recycled material.
The use of recycled CFRP in this form is currently unique. The CFRP produced by BMW’s joint venture partner at the Moses Lake plant in USA is made with electricity generated entirely from hydroelectric power. A total of more than 80 per cent of the aluminium used in the BMW i3 Concept is produced either using renewable energy or from secondary material.
And now we take a look at the i8. The i8 is quite a different vehicle from the i3 – while the i3 is a city roundabout vehicle, the i8 is a sports car. Unlike the i3′s EV power, the i8 is powered by two different power sources, which demonstrates the versatility of the LifeDrive architecture.
The LifeDrive architecture is constructed differently here – arranged in a vertically manner instead of the simple top-down horizontally split structure of the i3. The drive systems powering the BMW i8 Concept are integrated into the front and rear axle modules, with the CFRP Life module providing the bridge between the two.
The electric motor has been adopted from the BMW i3 Concept and modified for use in the BMW i8 Concept’s hybrid power train, where it is “tuned” to run with a smaller battery pack and in conjunction with an internal combustion engine. It drives the front axle, while a 220 hp turbocharged 1.5 liter three-cylinder petrol engine developing up to 300 Nm of torque drives the rear axle. Naturally, this gives the i8 all-wheel drive traction capability.
This is something new, as the previous BMW Vision EfficientDynamics concept used a diesel engine. Together, the two power sources take the vehicle to a governed top speed of 250 km/h. It hits 100km/h in under 5 seconds but consumes just 3 liters per 100km on the Euro test cycle.
SInce the i8 is a plug-in hybrid, it does not need as much battery cells as the electric-only i3. These battery cells are stored inside the Life module inside an “energy tunnel”, which is very much like a transmission tunnel. This also helps gives the vehicle a low centre of gravity, which helps with handling. The batteries alone give the i8 an all-electric driving range of approximately 35km, and they can be charged in 2 hours with a standard power socket.
BMW i is the embodiment of “next premium” for BMW, which extends the idea of premium to encompass future requirements of personal transportation. These cars still have quite a few years before they hit production, and in the meanwhile there are already a few other carmakers putting their EV products into the market – for example, we have cars like the Mitsubishi i-MiEV and the Nissan Leaf in the non-premium market, and US automaker Tesla in the premium market.
As part of project i, the BMW Group is currently conducting field trials in everyday conditions with conversion vehicles running purely on electric power. The ongoing trials in the USA and Europe with a fleet of more than 600 MINI E cars are already delivering important feedback on the demands the series-produced electric vehicles of the future will need to meet.
Added to which, a test fleet of over 1,000 BMW ActiveE vehicles – set for launch in the USA, Europe and China at the end of 2011 – will contribute valuable insights into the performance of these models in everyday use. Feedback from the customers trialling the MINI E and BMW ActiveE is channelled directly into the series development of the BMW i vehicles.
We’ve tried a few electric cars before, including one that’s technically from the BMW stables (read our previous story on the Rolls Royce EV). We’re really looking forward to trying out a BMW or MINI EV sometime soon, if not prototype versions of the the i3 or i8, perhaps one of the conversion vehicles like the BMW ActiveE or the MINI E?
Look after the jump for a full gallery and more videos of the i3 and i8.
Found At: http://paultan.org/2011/09/12/bmw-i3-and-i8-concepts-feature-new-lifedrive-platform/