A New Venture SIM-Drive SIM-LEI

The design appears to be as bold as a concept car, but the SIM-Drive SIM-LEI is a road legal, one-off prototype packed with new technology that could possible be mass-produced around 2013.  SIM-Drive, a venture enterprise, was founded in August 2009 with investment from Keio University and several non-automotive private companies.  It’s president, Hiroshi Shimizu, who is a professor at Keio University, has been researching electric vehicles for more than 30 years.

The business objective of SIM-Drive is to popularize electric vehicle technologies as quickly and broadly as possible.  That’s why he established a new business model called the “open source system”.  This system solicits corporations that are interested in electric vehicle business and received a fund of 20 million JPY from each corporation in return for the right to freely use the technology and findings that result from the development process.  Thirty four organizations, including two local governments of Japan, participated in the development of the SIM-Drive’s first advanced prototype SIM-LEI.

More than 300km Driving Range

With its 24.9 kWh lithium-ion batteries made by Toshiba, the SIM-LEI achieves a travelling distance of 333km on a single battery charge in the Japanese JC08 testing mode (simulating mainly city driving) as well as 305km at a constant 100km/h cruising.  In comparison to the Nissan Leaf electric car that has a range of 200km in the same JC08 mode with its 24kWh battery, the SIM-LEI’s energy efficiency is about one and a half times as better as the Leaf.

SIM-LEI’s technological characteristics comprise two major features.  One is so called “in-wheel motor”; a motor is directly connected to each of the four wheels, eliminating mechanical loss. The other is a floor frame that stores batteries and inverters so that most of the space above the floor could be used for passengers’ comfort and utility.

Inspired by Fish

The exterior of the SIM-LEI differs dramatically from what you see on the streets today.  First, overall width is narrow at 1,600 mm to reduce the frontal projected area, while overall length is relatively long at 4,788mm to reduce the drag coefficient value.  The protector mould on the front and rear doors covers the side impact beams, which protrude from the door’s main surface, to further reduce the frontal projected area. 

Viewed from behind, the rear appearance is even more distinct.  The rear overhang is very long and the sides of the cabin taper acutely towards the very small, trapezoid shaped back window.  Ichiro Hatayama, general manager of SIM-Drive’s Design Division and also a professor at Keio University, says “Conventionally, automotive styling often uses the feline form as a motif.  These forms rely on force to cut through the wind, and their Cd value can probably go no lower than 0.24.  What we should be looking at is fish.  We sought a form that ‘wears the flow around its body’ like river fish living in rapid streams or fast-swimming migratory fish”.

Thanks to this conceptual shift, the designers achieved the 0.19 Cd value. The unique form that defies the status quo embraced by today’s mass-produced cars is also the result of emulating fish.

Iconic Interior

The concept for the interior was “iconic design”.  According to Hatayama, “The proposition was to visualize the technological characteristics of SIM-LEI in a way that was immediately apparent”.   The result is dramatic.  While switches and buttons are integrated in the control pod located just behind the steering wheel, the displays, housed in the black “wall”, are laid out far away from the driver and the front passenger to emphasise the roomy interior space.

The large 19-inch LCD monitor in the centre of the “wall” displays navigation as well as rear-view images replacing the rear-view mirror.  A pair of heads-up display units projects some of the navigation information.  The navigation and audio are controlled with a smartphone placed on the control pod.  Since the side mirrors are small to reduce air resistance, the small monitors on both sides supplement them and displays images from CCD cameras integrated into the side mirrors.

Two Cars Will Follow

SIM-Drive already started its second project last January and is developing two cars. One is an advanced prototype that is a different size and has a different package from the SIM-LEI and the other is an electric vehicle based on an existing production car.  Since PSA Peugeot Citroen is participating in the project, the latter will be an electric driven PSA small car equipped with SIM-Drive’s “in-wheel motor” technology.  Wait and see!

Design Process

Exterior Proposal ActiveDrive

Exterior Proposal AeroNatural

Exterior Proposal ProSport

At the first stage designers of SIM-Drive made three proposals for exterior design. The “Aero Natural”proposal carries over the style theme of the “Eliica”, 370km/h super electric car developed by the company in 2004. The “Pro Sport”is intended to be a sport sedan for matured taste, and it has a notchback proportion. The “Active Drive”has an agile style designed for active people. Each proposal was developed with 3D modeling software and shown in two different style treatments.

Chosen Front Three Quarter View

Chosen Rear Three Quarter View

At the second stage the “Aero Natural”and “Active Drive” proposals were further developed and examined for engineering feasibilities. Then the “Active Drive”was chosen, but the shape shown here in 3D digital model is much different from the final design. After this stage a 1/5 scale model was made and designers were struggled in a wind tunnel. To achieve the goal of 0.19 Cd figure they opted to shift formal concept and revised the shape around the rear in particular.

Interior Proposal CoolZen

Interior Proposal Impact Space

Among many studies for interior at the first stage these two proposals were selected at the second stage. Both are based on the theme to replace a traditional dashboard with a “wall” that is laid out far away from the driver and the front passenger and housed several LCD monitors. While the “Cool Zen” proposal is designed having Japanese simplicity in mind, the chosen “Impact Space” is more dynamic and iconic.

Masatsugu Arimoto, Freelance Design Journalist

Born in Tokyo, 1954. Studied industrial design at Chiba University. After spending five and a half years at Nissan Diesel, now called UD Trucks, as a commercial vehicle designer, Arimoto became assistant chief editor of CAR STYLING magazine. Since the end of  1988 he has been acting as a  freelance design journalist and contributing to many automotive and design publications.