Green is all the rage when it comes to vehicles these days. Nearly every automaker showing cars at the International Motor Show in Frankfurt had an "eco-friendly" version to introduce when the trade fair opened to the press on Tuesday, Sept. 11.

New models on display boasted improved fuel efficiency and engines that run on batteries or hydrogen.

US automaker giant General Motors also unveiled new designs that rely on sustainable mobility. In keeping with the show's theme "See What Will Move Your Future," sustainable mobility includes a drastic cut in fuel consumption and carbon dioxide emissions.

But, GM's European president, Carl-Peter Foster, said that automakers would probably rely on a variety of solutions to make automobilies more environment-compatible.

Alternative fuels may play bigger role

"I think that basically what you will see is a competition of various technologies and ultimately the one that best suits the needs" of specific segments will win, Foster told reporters.

"I think that alternative fuels have to play a larger role," he said.

Toyota, however, has paved the wave in going green, with its Prius hybrid the leader in the industry. The Prius mixes an electric motor with a gas engine.

Even German automaker Porsche -- known for its luxury sports car -- had a hybrid version of its Cayenne SUV on display in Frankfurt.

And, other German manufacturers did not want to be left out in the cold: Volkswagen and DaimlerChrysler both had "clean cars" at the fair.

Germany's BMW, famous for its elegant vehicles, brought out the X6, a new sports utility vehicle with a hybrid engine that is due to go on the market in 2009.

"We're not just alking about cutting CO2 emissions, we're doing it," BMW Chief Executive Norbert Reithofer told AP news agency.

BMW says China copycats cars

BMW, however, has had to shift gears when it comes to marketing its models.

Even before the motor show began, the company had locked horns with Chinese automaker Shuanghuan. BMW said the Chinese-made four-wheel-drive CEO was a replica of its X5 model, which it stopped producing last year.

But, Karl Schössl, head of China Automobile Deutschland, the company that imports Shuanghuan's cars, said he was not concerned about pressure from BMW.

He told AFP at the car show in Frankfurt: "I am absolutely not worried" about the possiblity of cars being seized by officials.

BMW said last Friday that it had launched legal proceedings against the importer due to possible copyright infringements.

Shuanghaun's vehicles still on show

But, two different versions of the Shuanghaun car went on display anyway in Frankfurt, and BMW said it did not plan to have the models confiscated.

"We are not planning anything tomorrow [Wednesday] at 9 a.m.," a BMW spokesman told AFP news agency, though he did not rule out further action.

Schlössl claimed that German automakers wanted to keep Chinese companies away from the European market.

DaimlerChrysler had also taken issue with Shuanghaun, saying its Noble car was a copy of Daimler's Smart city car. The Noble did not go on display in Frankfurt.

More than 1,000 companies from around 40 countries are showing their goods at Frankfurt's International Motor Show, which will open to the public on Saturday, Sept. 15.