CLEVER

The CLEVER (for "compact low emission vehicle for urban transport") is a type of tilting three-wheeled motor vehicle that was developed in a collaboration between the University of Bath, BMW and a number of other partners from across Europe. CLEVER is designed as an alternative to conventional means of personal urban transport. The narrow body endows it with some of the manoeuvrability and congestion avoiding capability of a motorcycle, whilst offering comparable weather and impact protection to a car. Carbon emissions are reduced as a function of low weight and a small frontal area. The narrow track width requires that CLEVER tilts into corners to maintain stability; thus it is fitted with a Direct Tilt Control (DTC) system that uses hydraulic actuators linking the cabin to the non-tilting rear engine module.

CLEVER measures only 1 meter wide and has a maximum speed of approximately 50 mph. It runs on compressed natural gas, achieving a predicted 188 miles per gallon fuel efficiency. Construction of the first of five prototype vehicles was completed on Friday, April 21, 2006. Shortly after construction, track testing of a prototype vehicle revealed that, in certain transient situations, the DTC system could not guarantee stability of the vehicle. As of December 2012^[update], research into alternative tilt control strategies for the CLEVER vehicle is still on-going at the University of Bath.

CLEVER features a two-seat tandem layout, a single front wheel, tilting cabin, and a two-wheeled rear engine module. The total vehicle mass is approximately 332 kg (excluding driver and bodywork); with a 75 kg driver the static weight distribution is 39% front and 61% rear. The rear module does not tilt and accounts for approximately 40% of the laden vehicle mass meaning only 60% can be tilted to balance the vehicle whilst cornering. CLEVER’s wheelbase is 2.4m, as long as many conventional city cars, but there are no overhangs so total length is under 3m. The track width is just 0.84m giving a total vehicle width of 1.00m.

Whilst the Clever vehicle was intended to use a low emission engine burning compresses natural gas, the research prototype at the University of Bath uses a 13 kW 176cc single cylinder engine taken from BMW C1 scooter. The original CVT gearbox is retained (albeit modified to provide a power take off to drive the pump for the tilt hydraulics); belt drives are used to transmit power to the two rear wheels. Rear suspension is by way of independent trailing arms, adjustable Öhlins spring/damper units and an anti-roll bar. The front wheel is suspended by a leading four bar linkage with a single Öhlins spring/damper unit and uses a hub-centric steering system. A single track-rod transmits steer inputs to the front wheel from the output arm of a worm-gear steering box, the driver’s steer inputs are transmitted to the steering box via a modified wheel and column sourced from a BMW car.

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Wikipedia