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by Bill Godwin 0 Clockwork boost for buses
FROM time to time the automotive engineer's dream of a vehicle driven by energy stored mechanically within it surfaces into experimental form. The storage of braking energy and its subsequent utilization for acceleration of a vehicle, ie recuperative energy transfer, has also kept research workers busy although results to date have been of little practical value. (Regenerative braking of electric vehicles at least restores some of the energy to the supply or can be used for heating.) Now comes a report from Russia of an SIL158 bus used for trials of a novel type of recuperator in which a specially manufactured high-duty steel tape is used in a role analagous to that of a clock spring.
So far the solution to the problem of transferring kinetic energy to a storage flywheel has hinged on the design of a suitable drive coupling, preferably with infinitely variable ratios to maintain flywheel revs as vehicle speed decreases. The Russian development is based on a transmission from the drive shaft which, when braking is initiated, will wind a steel tape from one storage drum on to a second. As the vehicle is slowed down the diameter of the "take-up" reel increases while the diameter of the feed reel reduces.
Thus as the kinetic input decreases the speed of the feed reel remains near constant. This feed reel is in turn connected to an energy storage flywheel weighing approximately 80kg. Free-wheel devices and reversing mechanism allow the energy flow from the flywheel to be reversed through the tape drive when the vehicle is restarted. With the initial small diameter of what then becomes the "take-up" reel a high starting torque is available. The steel tape, of a thickness of 0.25mm, provides 350 revolutions of either drum and forms the sole connection between the drive line and the energy accumulator. Experiments with the SIL-158 bus indicate that energy recuperation alone would allow the vehicle — braked at 40 kph — to re-attain a ;peed of 34 kph, ie a very high degree of efficiency. Total weight of the instalation, excluding control and monitoring ;ear, but including almost 20kg for the neel tape, comes to 200kg. The developers of the device, at the University of Georgia, ilso claim important environmental benefits owing to the reduction of vehicle emission as well as significant reductions in service brake temperatures and wear.
0 Trolley/gyro hybrid planned
ALTHOUGH the original Oerlikon Gyrobus of the early 1950s provided a wealth of operating experience in revenue service in a single European operation its aims of combining the best of electric traction with the freedom from fixed overhead wires might have had more appeal if it had come 20 years later. That the idea is still around emerged from a recent announcement in Germany that the flywheel method of stored energy is proposed for a novel midibus system devised by bodybuilder Walter Vetter, of Stuttgart.
What makes the Vetter system -for which 6m-long 20/25-passenger vehicles are planned different from the pioneer Gyrobus is the additional provision of mains feeders over the full length of an acceleration lane at each stopping place. This would enable stored energy to be preserved for propulsion at optimum rolling speed. Sections of external mains feeders, of a design which would not require precise alignment or engagement of the vehicle collectors, could also be erected where severe gradients or congested traffic crossings call for a continuity of supply.
0 Stockholm night ban on heavies
NEW RULES controlling the access of commercial vehicles to the centre of Stockholm come into effect on April 1. From 10 pm until 6 am entry to the control zone will be restricted to vehicles not exceeding a gvw of 3.5 tonnes. For traffic and environmental reasons the movement of vehicle combinations longer than 12m but not over 15m will be permitted only between 9 am and 4 pm, and again between 6.30 pm and 10 pm.
The use of maximum-length 24m combinations in the outer sectors of the capital will, in future, also be confined to hours outside the main traffic peaks. Last month new regulations specifying illuminated sidemarkers for Swedish cv and psv longer than 6m came into force. These markers must not be more than 2m from the front and rear of the vehicle while the space between the markers must not exceed 6m so that additional markers must be fitted on vehicles more than 10m long.
In anticipation of additional safety legislation for 1974, headlamp washers and wipers are now being fitted to new road vehicles in Sweden. A modified version of the Volvo F 86 chassis incorporating an "emission and noise treated" TD 70 engine was shown at a recent exhibition of municipal vehicles in Kalmar. The blown 6.7-litre engine of 207 bhp is housed in a specially designed cowling reducing the normal noise level to 79 dBA. The front axle has been moved back to provide better access to the forward control cab and to give a better turning circle. A number of safety features were also fitted to the vehicle, including a TV rear viewer with a camera mounted on the drawbar trailer and electrically heated side mirrors.
While there is at the moment renewed talk of political manoeuvres to inhibit further expansion of goods transport by road — a trend, according to one parliamentarian, indefensible in a socialist society — the passenger scene is one of confidence and progress. With liberal C. and U. Regulations operators are able to use vehicles with lengths far in excess of any others in Europe. A recent example is the introduction of 14.5m (47ft 7in.) long Neoplan Cityliner coaches with seats for 60 long-distance passengers. The Germanbuilt three-axle vehicles are powered by Mercedes-Benz V 10 engines of 320 bhp and have Eaton drive axles. Fully laden the weight approaches 22 tonnes.
D New truck centre for Rotterdam
THE City of Rotterdam has given a loan. at 7 per vnt, of over £100,000 to Maatschappij tot Exploitatie van Vrachtauto centre VAC — to enable a new truck centre to be established in the dock area. The city has also guaranteed to bear up to 50 pc annually of any operating loss. Other shareholders include the local Chamber of Commerce, the well-known Heineken Brewery and Shell Nederland. Initially, the new facility will provide parking for 90 vehicles, a service centre, a motel with 24 beds and restaurant, and office accommodation for hauliers and shippers. The site is large enough to permit a considerable expansion at a later date.