Current prospects
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How much real progress with electrics and LPG in Britain and Europe?
by Stephen Gray
THE PRESENT quest for vehicles which can run on something other than petrol or diesel oil really sprang from the pressure to clean up the urban environment, but the escalating cost of oil and oil products has boosted this into a worldwide search for alternative fuels. If public transport could be switched to other forms of power unit there would be substantial savings in use of the previous fossil fuels, as well as cost and environmental advantages.
The two main alternatives being investigated are batteryelectric and liquefied petroleum gas (LPG) power units.
At the moment, more work is being done on electric vehicle development than LPG designs, despite the fact that there are thought to be plentiful supplies of the gas to come from North Sea oil.
Electric public service vehicles are not new ; at the turn of the century they were in use in several major European cities, including London and Paris. With their smooth, jerk-free power takeup and relatively silent, fumeless operation they would seem to offer ideal City transport, especially as they do not suffer from the inflexibility of trolleybus and tram. Unfortunately, their main disadvantage Iles in the battery itself. Modern technology has been unable to produce a light, compact battery which can provide sufficient power for long enough to give a reasonable range between recharges.
In spite of this drawback, work has been going on in Britain, the Continent and several other countries to produce a satisfactory bus using current technologies.
Two prototypes
In 1970 Britain's Department of Industry ' commissioned Crompton Electricars to build two prototype buses based on the Leyland FG-series chassis. The first bus started service with Leeds City Transport in, March 1972, and the second with Merseyside PTE in Jone of the same year. Intended primarily for applications such as Leeds, with its pedestrianised city centre, they were eventually used by 12 operators over 14 different routes for more than two years. With an urban service range of 56km (35 miles) and a maximum speed (fully laden) of 36km/h (22.5mph) the buses attained their design requirements although reliability was questionable.
Nevertheless, the DoI says it gained useful information from them. The Chloride batteries, which are housed in quick exchange containers at the sides and rear of the Willowbrook body, require eight hours at 75amp for a full recharge. After a year in mothballs, one of the buses is to be used as site transport at Harwell atomic research, while the other is expected to return to active service with a bus company.
Crompton says that although not closing the file on further psv development, it has no immediate plans to build more, preferring to concentrafe on light commercial vehicles.
Lucas and Chloride contenders
The Lucas midibus and the Chloride Silent Rider, two more British products, were both initiated by Mr Geoffrey Harding when he was development manager of the Greater Manchester Public Transport Executive (SELNEC as it then was). The midibus started service with the GMPTE in January of this year on the Manchester Centre-line route, a busy circular shuttle service round the city centre, where it works during the day—the batteries are recharged at night.
For the midibus project Lucas used a Seddon Pennine Midi body and chassis with a CAV 360V dc electric motor mounted underfloor on a separate sub-frame.
The 60 Lucas lead-acid batteries are situated at the rear and sides of the vehicle and the control system, specially developed by Lucas, is also rear mounted. The bus has an adequate range for its present route and did in fact once travel from Birmingham to Manchester, a distance of more than 144km (90 miles) without its batteries becoming completely discharged.
Very much a one-off prototype, no figures for economy are available, as service life has been too short. Lucas has produced only one bus, apart from a luxury eight-seat personnel carrier (which it does not regard as possible psv material) and there is only one bus in Lucas's development programme.
Unlike the midibus, Silent Rider was intended to operate in the morning and afternoon peaks, being recharged during the day. Since it started in service with the GMPTE in April of this year it has been on the Reddish to Manchester city run, a distance of some 9km (6 miles), working three hours in the morning and 2/ in the afternoon with a sixhour recharge period between them. Silent Rider uses a modified Seddon RU33 chassis with a lightweight body capable of carrying 42 seated passengers and up to 15 standing. The electric motor, supplied by Electro-dynamic Construction, gives the bus a top speed of 65kmh (40mph) with an operational range of 60km (37 miles).
Chloride built the bus primarily to test the various units that go to make up the drive train, and during its service life to date those failures that have occurred have been of a minor nature involving simple components such as plugs, sockets and so on. Once again, like the Lucas bus, service life has been too short to get a fair comparison with a similarsized diesel vehicle. It was expected in some quarters that a fleet of Mark II Silent Riders would be built, but although Chloride is holding talks with various government departments about further plans for battery buses, so far nothing has been forthcoming.
National with trailer
Latest of the British-built buses is NBC's converted trailer-towing National, which has just been given DoE dispensation to operate—necessary because of its 44ft-plus length with trailer. In choosing to tow the batteries in a trailer NBC is emulating the German GES buses. The conversion of the National single-decker was carried out by NBC's subsidiary, Ribble Motor Services, of Preston, with British Leyland's co-operation and using Bosch eIectrics.
The rear of the bus has been modified and strengthened to take the drive motor and towbar fixings, and a different axle ratio employed to cope with the electric motor's torque and rev characteristics.
NBC has differed from the Germans by using a two-axled trailer, purpose-built by Dysons of Liverpool, and it charges the batteries without removal from the trailer. Despite earlier objections by the DoE to its length, the prototype bus is now running on the Runcorn busway in Lancashire. So far a maximum road speed of 62.6km/h (38.9mph) with a range of between 96.5km (60miles) and 128.7km (80 miles) has been achieved without the need to recharge.
The main driving motor provides a form of engine braking, but the original air brakes are retained, the compressor being driven by a separate 360V motor which also drives the power-steering pump.
When the West German GES consortium (an offshoot of the Rhine Westphalia Electricity Authority), was set up, its brief was to build a bus which could be used for long periods, covering quite large distances. The fact that some of its buses work for up to 19 hours covering 340km (211.5 miles) is proof of their success. Monchengladbach saw the first buses in service in October 1974 and these were claimed to be the world's first commercially operated fleet of electric buses.
MAN was responsible for Daimler-Benz used a standard 1 lm (36.1ft) city bus for the conversion, but reduced the carying capacity from 110 to 100 passengers to keep it below 16.25 tonnes (16 tons). Finance has been found to build a fleet of between 20 and 30 of these buses which, it is hoped, will start service in Southern Germany by the end of 1976.
Thirty of the all-electric 12seater transporters are being used by the Rhine-Westphalia Electricity Authority as personnel transport and orders for 50
French hybrid
The French too have several prototypes in service, including Saviem's diesel-electric hybrid which is unusual in having two asynchronous motors each driving one rear wheel and a three-phase alternator driven by an MAN diesel through a 1 :7.2 ratio multiplier. RATP (Regie Autonorne des Transports Parisien) took delivery of the bus in 1971, which was built to carry 70 passengers. RATP was closely involved with the project and it also collaborated with Alsthom in the construction of its Electrobus, which again features a hybrid set-up, this Clermont-Ferrand in 1972 and 1973 respectively and the latter vehicle had a top speed of 60krnh (37mph) and a range of 120km (74.6m1).
The LPG front
There are hopes that sufficient quantities of LPG from the North Sea will be forthcoming to make its use as a fuel for psv a viable proposition in Britain. Unfortunately, at the moment LPG does not enjoy the tax rebate advantage that diesel oil for psv does, and so comparative figures with di esel-engined vehicles so far indicate a higher cost per mile. Neverthe less, LPG-powered buses do offer many of the advantages of battery-electric vehicles when compared to diesel. They are smoother running and quieter and their exhaust emissions contain fewer noxious gases.
Double-decker In service
In 1973 Cleveland Transit in Northumberland brought into service a Daimler Fleetline double-decker, converted to run on LPG. Cleveland chose to change the original Gardner diesel for a Rolls-Royce unit which had been modified to run on gas. From April 1974 to March 1975 the bus covered some 21,000 miles with an overall fuel consumption of 3.4mpg. Although in April this year the engine had to be changed (owing to a small compressor oil-pipe leak causing engine seizure) the only other faults had been relatively minor ones. Cleveland had hoped to introduce a second vehicle into service with Allison transmission, but finance could not be assured, so the project was dropped. The Daimler, however, is to continue in service for a further period.
Rather than trying to find and install a suitable petrol unit, London Transport is con verting a standard diesel bus to run on LPG. The main changes to the engine will be the fitting of deep-dished pistons (to lower the compression ratio), spark ignition and a new fuel system. Yorkshire Autogas is co-operating on the project, supplying fuel equipment and expertise. LT hopes the bus will be running by early next year when it will be able to evaluate its performance and economy.
On the Continent, the Dutch Research Institute for Road Transport is probably the leader in LPG technology as applied to road vehicles. The Dutch have worked on conversions of psv with several other countries, and were responsible for the DAF city bus which is running in Amsterdam. Like the proposed London Transport bus, •the DAF retains its original diesel engine, which has had the compression ratio lowered to 10: 1 and an electronic spark ignition system fitted. The fuel is contained in three large cylinders running along the length of the vehicle in the centre, high enough to be protected from damage. The Institute is unable to comment on the vehicle's reliability as yet, but it says a report on its progress should be available in a few months' time.
Saviem and MAN are also understood to be working on LPG conversions, but to date no details are available. Some other countries, such as Spain and Austria, are experimenting with LPG/diesel mixture.
The research for alternative fuels by vehicle manufacturers and major operators is extensive throughout Europe. How soon the industry will take advantage of these researches is not yet clear, but the benefits cannot be long delayed.