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CLEVER: A Three-Wheeled, Natural Gas, Two-Seat Urban Vehicle


A European research consortium is wrapping up a three-year project to develop a three-wheeled, natural-gas powered micro-car: CLEVER (Compact Low Emission VEhicle for URban Transport).

CLEVER, a €3.3 million (US$3.9 million) effort, is an enclosed two-seater that combines the safety of a microcar, and the maneuverability of a motorcycle, while being less polluting than other vehicles as it runs on compressed natural gas.

Its strengthened frame will protect the driver in a crash and the vehicle will have a top speed of approximately 50 mph.

The 230cc BMW engine—modified by Institut Français du Pétrole (IFP) to use natural gas—produces 12.5 kW (17 hp) of power and maximum torque of 15.5 Nm at 6,300 rpm.

IFP increased the swept volume of the engine cylinders, allowing the engine to run more slowly and bringing several benefits. The lower engine speed both reduces emissions and lowers engine friction, which enhances fuel efficiency. It also produces less noise. The increased displacement contributes to the higher torque, providing the level of acceleration needed in urban traffic.

Fuel consumption is estimated to be 2.4 liters/100 km gasoline equivalent (98 mpg US), with 59.5 g/km of CO2 emissions.

The fuel tank system.

The compressed natural gas is stored in two removable cylinders that are custom designed for ease of handling and refilling. The two connected gas bottles provide a range of approximately 150 km (93 miles).

A problem with three-wheel vehicles with a symmetrical wheel layout is the tipping moment when cornering, which cannot be controlled at high speeds if the vehicle has a short wheelbase.

To solve this problem the vehicle’s center of gravity can be moved towards the center of the corner, for example by angling the complete vehicle—just as a motorcycle does when it corners.

This is the approach used by “tilting three-wheelers”—and there have been two basic technical methods to achieve it:

  1. Change the camber of the two parallel wheels (front or rear) with or without tilting the vehicle.

  2. Angle the vehicle around a pivot relative to the axis of the two parallel wheels.

Vehicles that use the first concept have been around since the forties (Ernst Neumann-Neander 1948) and the method has regularly been used for concept cars (Mercedes Benz F300 “Life Jet” 1997).

Vehicles that use the second concept include, for example, the “GM Lean Machine” dating from 1983, the “Carver” from Vandenbrink and various scooter-type vehicles from Honda, including the Honda Gyro/Honda Stream dating from 1984. There has been a BMW concept on this basis in the BMW Museum in Munich since 1991.

The cabin-tilting CLEVER. The rear section, with the engine, remains upright, while the cabin tilts.

The CLEVER vehicle is a cabin tilter, with the system designed by the University of Bath. The cabin with the front wheel is connected to the power unit and the two rear wheels by a pivot bolt. The rotary movement of the cabin is produced by two hydraulic cylinders (actuators) that are installed between the cabin and the power unit. The actuators create the rotary angle of the cabin of +/-45° relative to the vertical power unit.

The hydraulic system consists of a pump that is driven direct by the engine and a pressure accumulator that maintains the oil pump if the pump suffers a defect. The two single-action hydraulic cylinders are controlled by an electromagnetically actuated valve.

The signals for the hydraulic control valve come from a freely programmable computer that processes the input signals from a sensor system, such as speed, tilt angle of the cabin and lateral acceleration.

CLEVER was funded by the European Commission with the Growth Programme of the Fifth Framework Programme. Partners included:

  • Technical University of Berlin, Institute for Land and Sea Transport (TUB), Berlin, Germany
  • BMW
  • Cooper-Avon Tyres Ltd, Melksham, Great Britain
  • ARC Leichtmetall Kompetenzzentrum Ranshofen GmbH (LKR), Ranshofen, Austria
  • IFP
  • TAKATA-PETRI AG, Berlin, Germany
  • University of Bath, Department of Mechanical Engineering, Institute for Power Transmission and Motion Control, Bath, Great Britain
  • Universität für Bodenkultur Vienna, Institute of Transport, Vienna, Austria
  • WEH GmbH, Illertissen, Germany

(A hat-tip to Wolf Faust!)




looks like a motorbike with an attached fuel tank.

Does CNG really good as car fuel? I kinda like the idea of homemade biogas system(including H2S filter and CO2 wash) and you make your own fuel.


That tricycle reminds me the ecomobile. It looks too furturistic. Regardless of its power source, I'm skeptical about its widespread possibility. It seems the public perception about safety is directly proportional to the weight and bulkiness.


Besides they want far too much money for it. The Science channel showed it last night and they said $50K Canadian. If they want to sell these things they will have to get the price down.


Well, according to "Spiegel" this vehicle is developed for technical and material study only, there are no plans for serial production yet. If a market demand shows up they "might" bring it to maturity phase. The price will be then around €9.500 about $11.128 US.
(Price source: The Guardian UK)

But there is definitely no market for such a vehicle. Too slow for a fun racer, too limited cruising radius, no storage room at all plus a stupid gas filling system which could be from the sixties.
For a 21st Century lightweight threewheeler I would prefer an e-engine. However, the hole "project" is nothing else as tax money burning.
No market, unemployable for mass use - just senseless and disappointing. (European SOCIALIST Union pumps 3.3 Mio. taxpayer money into that cra..wheeler)

Daniel Johnston

A bit less of the gung-ho supremacist Yankee nonsense, please.

Mike Weindl

This vehicle is not built for being a "FUN RACER", the idea is to drive it in the city or for commuting where it's speed is probably more than enough. I can very well
imagine that in europe (why "socialist"?) this car could
be a success. The two seater SMART which you can see everywhere in Europe's cities since a bid more than a decade, shows that "socialist" europeans are maybe a bid
more open for new ideas.


I wouldn't pay $5,000 for it in it's present form. Maybe with a diesel hybrid in it.

little shop

There is a market. The 'Carver' is a very similar vehicle selling for 30000 euros or so in europe. The Carver has more hp but its 3x the projected price. It would be a niche vehicle but $12000 would sell. There are many bikes in that price range.

Daniel Johnston

I actually quite fancy a wee car like this, I'd just rather it was electric. The reva's not bad, but 40mph isn't enough to go on a dual carraigeway. Still this would get me to my family and back, which is all I'm really after. Just not sure the Co2 saving is enough to justify it.


Keep it under US$10,000, and I'd buy it tomorrow. A perfect commuter vehicle.


Two seats, weather protection, luggage space(small!), urban and suburban speed capable and half the road plan area of a small european car in a body shell that you would want to be seen in.
If a possible production version carries all that over
it would sell.


I agree with Lucas. I believe there is a market for vehicles like the sporty "Carver" in Europe as well as those looking for "greener" alternatives for the daily commute around town. Bottom line...I'd buy one for around $10,000 - $12,000 USD.

Ray Kemp

There is an overwhelming need for a vehicle of this nature here in the United States. The market, with the proper introduction and consumer education, is enormous. The Trivette ll is one example of what is currently available, although it is only sold as a kit. I think the ideal design would have a little more speed so it could operate on major highways and with the proper aerodynamic design does not require tilting. Also, the safety feature are definitley nice but they seem a bit extreme when you consider SUV roll over, convertibles, pick up trucks and other less safe vehicles. These vehicles are going to be more manuverable. I would love an opportunity to promote the development of this type of vehicle.


This car isn't any advance from what we're driving it should be more comfortable, have more space for personal stuff and maybe another chair. Remenber that a green car for beeing successful needs to be useful.

kevin ward

there's defintely a market for vehicles like this especially in cities like London that use congestion charging. This vehicle would be zero rated. A safe covered vehicle that could deal with the vagaries of the London weather and is safe would sell. The price needs to be around £5K though-not much more.


the tilting system is admirable but back wheels
may tend to be unstable while doing curves.

Patrick Labay

When I studied in Innsbruck Austria some 13 odd years ago, I had the pleasure of seeing this design study in Munich in person. It is a fabulous idea! A motorcyclist in the USA, I can attest that this transportation has great potential, as rain and sleet and occasional cold or nasty weather and absence of public transportation makes a motorcycle/scooter impractical. It's even more technologically important because of the market niche it creates. Fun, groovy transports like these, coupled with low price and when available-green lanes, and we will have destroyed a significant problem with over crowded roads and fossil fuel cost and obsolesence. Make it Happen AMERICA! DO it! Do it!


A covered 3-wheel motorcycle would sell in US cities, plenty of city commuters (including me) would love to ditch our 3/4 empty cars for something like this. Put Honda and Suzuki together to work on this and they could bang something out that would cost $12K, look good, and be fun to drive. Even using regular gas, the MPG would rival a prius. a plug-in version would be great as well.


at a glance:1/3 the weight,1/3 fuel consumption,1/3 emissions- only 1m width,carries 2 people {80%of cars ,average weight 1400kg,have only 1 person in them in peak hour traffic in melbourne -Australia with speed limits of 50kmh in suburbia and inner city and 11o kmh absolut top in country Victoria--with petrol prices rapidly approaching $1.5o per litre--the CLEVER project deserves to become a success story!!--I have one for under$1oooo !!The fun factor of driving a tilting cabin 3 wheeler would alone be a great incentiv -

Mr K

If the price is right these would sell a lot. I am actually looking for something similar right now. In the summer I ride my bike to and from work, but in the winter I need a three wheel car. Here (in Sweden) motorcycles park for free and this also applys to three wheeled bikes. Plus the tax and insurance is a lot less than for a car. And you get better milage. I've been looking at the Grinnall Scorpion but I need a top so I can drive it in rain and snow. The Carver is too expensive.
Anyone have any other suggestions?


John G

The CLEVER would be welcome in my driveway right now.

The Carver is just as impresive but cost WAY to much.

That alone will be the Carver's down fall, $45,000+, it just limits the market to a slect few.

Drop it down to $10 to $13,000 out the door and you will not be able to keep them in stock.


hey if this car is out in 2-3 years when i get my licnce and its under 10,000 i would buy it looks like a great little first car plus i like the fact that it will have a low impact on the enviroment


hey if this car is out in 2-3 years when i get my licnce and its under 10,000 i would buy it looks like a great little first car plus i like the fact that it will have a low impact on the enviroment


This is a great way of transport & I'm sure "The Clever" would sell perfectly anywhere in the world especially due to rising fuel prices.I difinitely buy one, no use having two family cars paying expensive car insurance etc.. I need one of these for work transport since I don't have public transport as an option. Make this happen for a reasonable price, anyone out there listening?

joe novo

lets see the first one, get the price down where the common man can purchase, and you will have scoreda true winner. i would go for one in a minute!!

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