European bus builders facing change

Most small buses and coaches in Europe are either derived from popular panel vans or based on light truck chassis. ‘Proper’ buses and coaches tend to start from about ten tonnes gross, or approximately a 40 passenger capacity.

Buses and coaches tend to fall into three main categories, often with some carry-over of features between them. First, there are city and suburban buses, invariably with a large part of the floor only one step above the ground. The next main category is the interurban vehicle that has some bus features, such as easier access and wider doors, combined with some coach features; principally seating that is more comfortable. The third main category is the luxury coach, used for express, touring and private hire work. This article is concerned principally with city buses.

There are two main vehicle concepts. The first is the complete integral bus, built and supported wholly by one manufacturer. This concept is widely used in major markets such as France, Germany and Italy. The second is the combination of a chassis built by one manufacturer with a body made by an independent builder. These vehicles are dominant in the British Isles and the Iberian and Nordic countries. With the advent of low floor buses, more of the structural strength of the vehicle has to be carried by the bodywork, therefore there has to be close collaboration between chassis and body builders.

There is an old adage that half the manufacturers in the industry disappear every ten years, through amalgamation or closure and that trend is continuing. Several large factories in Central and Eastern Europe have closed down since the break-up of the former Soviet bloc, including Ikarus of Hungary, once the largest bus builder in the world.

Smaller specialists in Western Europe have also closed down. Only the larger companies can bear the great costs of research and development for the high levels of legislation that now control the construction and use of buses.

For many years, a car, van or truck that was built in one member state of the European Union and complying with construction legislation, could be sold in any other member state without the need for any further homologation. It was only in 2001 that the EU ‘Bus Directive’ came into force. It harmonises the regulations on what can broadly be described as the non-mechanical part of buses, i.e. the area occupied by the driver and passengers. There is currently a transitional period during which the Bus Directive will supersede domestic regulations in the member countries, except for special vehicles built in very low volumes.

Concurrently with the introduction of the Bus Directive, there is the concept of Whole Vehicle Type Approval. Whereas vehicles were traditionally inspected and certified by an independent Government agency, manufacturers will be given the power to self-certify, provided they can demonstrate conformity of production. Those that are building long runs of relatively standard vehicles will find it much easier to comply than those who do not work to the best international standards of quality and consistency.

While the regulations permit separate approval of chassis and bodywork, it is reasonable to predict that the number of permutations of different makes will have to fall. Chassis builders will have to be more selective about their body building partners. Customers who want a substantial deviation from standard products will face the cost of Type Approval. Long term, the leading manufacturers of integral buses are likely to be the main beneficiaries.

There is still too much of a tendency for customers, especially the larger ones, to insist on putting their own stamp or identity on city buses. They cannot alter the chosen drive train, apart from the availability of some options such as power ratings or the number of gears. They tend to put their stamp on the interior of the vehicle. There are several competing suppliers of seats, destination equipment, doors, air conditioning and other major components.

To take just one example, there are more than 500 different door makes and systems available in the Western European market with various types of operating systems, numbers of leafs, inward or outward opening and so on. For the manufacturers, this can be a nightmare. They need to test and prove each different application, requested by a customer, before going into production.

The European Union has introduced successive levels of reductions in emissions from diesel engines during the last 15 years. New models first registered on or after 1 October 2005 will need to comply with Euro 4 emission levels. For existing models, the date of compliance will be 1 October 2006. The date for the introduction of the next stage, Euro 5, for new and current models will be 1 October 2008 and 2009 respectively.

During this progression, the oil companies came, late and reluctantly, into the equation by refining and distributing ultra low sulphur diesel.

If we compare 1990 and 2008, particulate matter (i.e. the soot that used to come out of the old diesel engines) will have fallen by 95%, carbon monoxide by 88%, nitrous oxide by 87% and hydrocarbons by 82%. Those are impressive reductions, on any scale.

One of the benefits of ultra low sulphur diesel is that it can also be used in older vehicles, even those with engines built prior to any emission limits; it makes their emissions noticeably cleaner. That is important for the image of the bus industry. Although the numbers of buses in circulation are far below the numbers of cars and other commercial vehicles, buses are very visible, spending a large part of every day in busy urban centres.

In some countries, politicians have demanded even cleaner vehicles. Trolleybuses are still widely used in many parts of Central and Eastern Europe and have enjoyed a slight revival in countries like Italy.

Compressed natural gas is also a popular alternative, with even lower emissions than diesel, although the difference at the exhaust pipe is not as wide as it was a few years ago. The problem with gas is that it has to be carried in large tanks on the roof of a low floor city bus vehicle, adding around one tonne to the unladen weight and therefore restricting the numbers of passengers that can be carried, if maximum permitted axle weights are not to be exceeded.

Stockholm has regularly specified ethanol fuelled buses with Scania engines. Emissions are very low, but fuel tanks need to be 60-70% larger than those of diesel buses to achieve the same operating range. It takes a lot of energy to produce ethanol, but it can be done away from a crowded city centre. The fuel is also quite corrosive.

More recently, Mercedes-Benz had led the way with trials of fuel cell buses in ten selected European cities. This product has enjoyed substantial funding from European and national authorities. The only emissions are water, usually in the form of steam, but the manufacturing cost of fuel cells is prohibitively high. It is a challenge for manufacturers – they have to get volumes up massively before costs will fall to sensible levels, but how do they achieve that?

Another development is the hybrid bus, where a small petrol or diesel engine, encapsulated to reduce noise and running at a relatively constant speed, drives a generator that produces an electric current fed to a series of batteries. When the vehicle accelerates or climbs a hill, its electric motor draws current from the batteries. When it descends a hill or brakes, energy is regenerated, giving an efficient step-free and more silent drive system. The hybrid vehicle costs more than a conventional diesel bus, but the concept is likely to become more refined in the next decade or so.

In October, the major international Busworld exhibition will be held in Kortrijk, just as Euro 4 emission limits for new models start to come into force. There are two quite different methods of achieving the necessary reductions in exhaust gas emissions. One is Selective Catalytic Reduction (SCR), which requires the injection of an ammonium-based liquid additive into the exhaust gases to reduce emissions to the necessary level.

The additive is known as urea or carbamide and has to be carried on board the vehicle in a separate tank. The supporters of SCR claim that consumption of urea will be around 2% of that of diesel and diesel consumption itself should be improved by around 5%. It cannot be pre-mixed with diesel, like an additive, because the dosage has to be metered precisely by an electronic control unit that senses how hard the engine is working. A urea tank is typically about twice the size of walk-luggage for an aircraft.

Urea will be distributed by chemical companies and is not a major logistical problem for a bus fleet, because vehicles always return to the same depot each night. The chemical companies will supply the refuelling facility and, by using GPS, will replenish the tank whenever its contents fall below a certain level. When additional new buses with SCR technology are acquired, the chemical company will take away the smaller tank and replace it with a larger one. The cost of the tank and replenishing it is included in a cost per litre price.

The main challenge for bus designers is to find somewhere to put the urea tank. They all want to maximise the area of low floor buses to make it safer and easier for passenger circulation. Already, wheels, tyres and the driveline must be located somewhere on the low floor, so finding space for the urea tank is another challenge. It might just fit under a double seat.

The other technology is called Exhaust Gas Recirculation (EGR). Some of the exhaust gases are cooled from around 600ºC to 35-40ºC before being fed back into the engine. The cooled exhaust gas is mixed with fresh air and fills the cylinders. Because the exhaust gas contains water and carbon dioxide, the concentration of oxygen in the intake air is reduced. Water and carbon dioxide have higher specific heat capacity than oxygen; therefore the blend decreases the temperature as well as the speed of combustion. The formation of nitrous oxide is greater at high temperatures; therefore EGR reduces its formation without increasing fuel consumption.

Two of Europe’s most respected engine manufacturers, MAN and Scania, have opted for EGR, but MAN also adds a self-cleaning particulate filter to the exhaust system. EGR does not require urea and the tank to carry it. Both manufacturers claim that there will not be a penalty in fuel consumption and Scania is confident that the technology can be taken forward to Euro 5.

Ranged against them are other respected engine builders such as Cummins, DAF, Iveco, Mercedes-Benz and Volvo. They say that SCR can easily be adapted for Euro 5 and beyond and is therefore the only realistic way forward. It will certainly be fascinating to listen to the various claims and counter-claims for the respective systems when new models are launched at Kortrijk in the autumn.

Bus builders also face the challenge of making their vehicles more attractive. In some countries, they are seen as the transport of last resort, used by those who do not own a car. Those people often include the elderly, but we are now reaching a stage where many elderly people have owned cars for most of their lives and are not prepared to give them up. The industry has to find ways of attracting non-captive passengers to its services and that cannot be done without the active collaboration of city authorities.

Research has shown that car owners are willing to use trains and trams but many resist riding on buses. New tramway systems are prohibitively expensive to build and they typically serve only one or two corridors in a city, benefiting a small percentage of the population. For much the same amount of money, an entire bus fleet can be replaced, serving all the population.

There is growing recognition that we cannot all use our cars all the time. Particularly in the Nordic countries, there is strong concern about the environment and that will make people use public transport as an alternative. Park and ride schemes, linking city perimeters with the centre, are also gaining in popularity. People will also use buses when they perceive the door-to-door journey time to be faster.

Recently, Volvo, Wrightbus – a major bodybuilder in Northern Ireland – and FirstGroup, one of the large private sector bus companies in the United Kingdom, came up with an innovative new vehicle, known as Streetcar. It is based on an articulated Volvo bus chassis, but the completed vehicle looks like a rubber tyred tram. It undoubtedly has passenger appeal. The interior has been laid out with a variety of seating, including club areas that are popular with groups. The driver sits in a separate compartment, with passengers either having to use prepaid single or multi-journey tickets, or smart cards.

The other major innovation in recent years has been the introduction of buses with a large part of the floor only one step above the ground. In most continental European countries, the low floor extends from the front to the very rear of the vehicle, often serving a third door behind the rear axle. In the British Isles and the Nordic countries, customers prefer a low entry layout, with the floor only one step above the ground up to a point just ahead of the rear axle. Seats above and beyond the rear axle can easily be reached by more agile passengers.

Low floor buses are often described as wheelchair accessible. Using a ramp at a stop where the height of the kerb is compatible with the height of the floor of the bus allows wheelchair passengers to get on and off very easily. However, relatively few of them use bus services. Operators have found that low floors are also helpful for many other passengers, including the elderly, people with luggage or heavy shopping, those who are temporarily disabled and parents with small children. All of them can get on and off buses more quickly, contributing to faster overall journey times.

The European manufacturing industry is going through a period of consolidation as it prepares for Euro 4. Mercedes-Benz acquired Setra in 1995 and its European bus operations are now controlled by a wholly-owned subsidiary, EvoBus. It has successfully rationalised its product ranges, achieving considerable economies of scale.

The EvoBus rationalisation became the model for other mergers. MAN put its own ailing bus operation together with Neoplan’s business and has successfully turned the joint operation into a profitable business, one year earlier than forecast. Known as NEOMAN, the new subsidiary builds city buses for many European markets in factories in Poland, where labour rates are much lower. Bus building is a labour intensive industry; therefore, savings in costs are significant.

Irisbus is a wholly owned subsidiary of Iveco and is busy integrating the former Iveco and Renault bus and coach ranges. The new ‘convergence’ models will start appearing shortly. Again, by rationalisation and reduction in the variety of parts, Irisbus expects to achieve greater economy and to retain its strong position in France, Italy and Spain.

Scania, consistently the most profitable truck builder in Europe, took a knife to its bus building activities a few years ago. A sprawling factory in Katrineholm was closed down and chassis production was transferred to the main truck plant at Södertälje, near Stockholm. Nowadays, a considerably smaller workforce is building more chassis than ever before, as the Scania bus and coach subsidiary enjoys record sales and output. All body building activities have been transferred to Poland, Estonia and St Petersburg, the last only for the Russian market.

Volvo is also busy turning round its bus building activities. The company is strong in the Nordic countries and the British Isles and also has a large factory in Poland from where it hopes to supply more vehicles to continental Europe.

One must not forget VDL, a Dutch engineering concern that now controls all the bus building industry in its own country and also Jonckheere of Belgium. They are in the process of converting a number of smallish units into a fully joined-up group, based on DAF running units.

Many European city bus operators are still owned by the public sector and order levels can fluctuate, depending on the availability of funding. Fortunately, Europe’s bus manufacturers look to be in better health now than they were three or four years ago, but they face some daunting challenges, now and in the short to medium future. Further consolidation is inevitable.