The Brazilian units of rivals Bosch and Magneti Marelli are sparring over the next generation of flex-fuel cars in Brazil.

Encouraged by recent strong growth in sales of flex-fuel vehicles, the two fuel system specialist suppliers are pouring money into research to make flex-fuel systems, well, more flexible.

In their first full year on sale in Brazil, cars able to run on petrol, alcohol or a blend of the two took about 24% of the market. Last month they accounted for a 30% slice of new car sales. But local automakers want more options and the suppliers are responding quickly.

Bosch and General Motors jointly developed the Astra Multipower sedan Multipower that runs on petrol, alcohol, a blend of the two - and natural gas. The vehicle was launched last month and is the first Brazilian-made vehicle that can run on three different types of fuel. Bosch has also joined with Volkswagen to develop a tri-fuel Polo sedan that will debut early in 2005.

Bosch has been developing this new flex-fuel system in Brazil since 2002, encouraged by the growing number of cars that run on natural gas as an alternative to petrol. The Brazilian government reckons there are 750,000 natural gas-powered vehicles on the country's roads.

Magneti Marelli has responded with a system called tetra-fuel' which it is testing on a 1.8-litre Volkswagen Parati compact station wagon and a 1.3-litre Fiat Siena compact sedan.

The Magneti Marelli system allows engines to run on alcohol, natural gas and two types of petrol: pure fuel (E0) and the Brazilian brew that blends in about 25% anhydrous alcohol).

Renault's earlier Hi-Flex system, developed by the French automaker and produced by Siemens, works with both types of petrol but not natural gas.

"We will introduce the first tetra-fuel system cars at the end of 2005. Automakers can export such cars to other countries with a large natural gas-powered fleet such as as Argentina", said Magneti Marelli Brasil research manager Carlos Damasceno.

The company's tetra-fuel system has a unique electronic control unit that adjusts 'mapping' to control the volume of fuel needed, the air/fuel ratio mix and the injection timing. The engine is equipped with a natural gas injector and a pressure regulator and the prototypes, as you'd expect, each have one tank for liquid fuels and a second for natural gas.

The prototypes also have a dashboard button for the driver to select liquid fuel or natural gas but production cars will make the choice automatically.

"The car will start and run on natural gas but, if the control unit determines that it needs more power, such as when overtaking or climbing hills, it will switch automatically to liquid fuel, returning to natural gas when appropriate. When gas runs out, the engine will switch to liquid fuel again. The driver will always be using the best fuel for the current conditions," Damasceno said.

While Magneti Marelli is focusing on the dual-fuel market, and also eyeing exports of its alternative fuels technology, Bosch is working on the next evolution of its tri-fuel technology and is trialling a so-called Motronic Tri Fuel system with turbocharger in a Volkswagen Polo hatchback.

"The turbocharger compensates for the lack of performance caused by the characteristics of natural gas", said Bosch Brasil product manager Fabio Ferreira.

The turbocharged tri-fuel 1.6-litre engine in the prototype develops 104hp on petrol, 109hp with natural gas and 119hp using alcohol. The same model with naturally aspired engine puts out just 86hp on natural gas compared with 101hp burning petrol and 103hp drinking alcohol. The power varies according to the blend of alcohol and petrol in the tank.

Both suppliers the flex-fuel segment will grow significantly in 2005.

"The automakers will introduce more flex-fuel models and their market share will grow from 30% today to 70% by the end of 2005", said Damasceno.

Volkswagen, General Motors, Fiat, Ford and Renault all produce flex-fuel cars in Brazil and all have plans to launch new models running on more than one liquid fuel.

Citroën and Peugeot will enter the flex-fuel segment next year.

Rogério Louro