Carmakers selling in the United States are not convinced the hybrid is the only immediate solution to reducing vehicle fuel consumption.

BMW chairman Helmut Panke, delivering the keynote speech to the New York motor show, reportedly said the typical petrol-battery hybrid technology popularised by Toyota's Prius is only one solution.

"On the way to the hydrogen economy, we will have different solutions, but right now 'hybrid' seems to be the right buzzword," Panke said, according to Reuters, which noted that he later compared fuel cell vehicles with amusement-park bumper cars.

Elsewhere around the show, industry executives reportedly said they also are developing alternatives to the petrol-fuelled internal-combustion engine.

A Toyota spokesman at the show told Reuters annual Prius sales are expected to rise from 35,000 to 47,000 units this year, while dealers are reporting a four-to-five-month waiting list. The carmaker will launch hybrid Highlander SUVs next February, following production of a hybrid version of its sister vehicle, the Lexus RX400h.

"By 2005, we want 300,000 hybrids in service," Toyota spokesman John McCandless told the news agency, while not failing to note that Ford has licensed its hybrid engine technology from his company.

American Honda Motor US sales chief Bill Colliver told Reuters the company has not announced plans for other models outside a hybrid Honda Accord to be introduced this autumn - he denied speculation the company's Acura division plans to produce a hybrid version of the RL luxury sedan [known as the Honda Legend elsewhere].

General Motors spokesman Mike Albano reportedly said the company intends to expand sales of two hybrid models - the Chevrolet Silverado and GMC Sierra full-size pick-up trucks - to the public in 2005, and is also developing Chevy Trailblazer and GMC Envoy utility vehicles with "displacement on demand" (DOD) eight-cylinder engines, which shut down cylinders when a driver needs less power.

GM sees 1 million DOD engines on the road by mid-2006, the spokesman said, according to Reuters.

Chrysler recently introduced a new 5.7-litre Hemi V8 engine with DOD as a highlight of its new Chrysler 300C/Dodge Magnum model lines and, at New York, debuted the engine in a fully redesigned Jeep Grand Cherokee line, claiming a first for the technology in the SUV segment. The engine is also offered in Chrysler group light trucks.