Toyota Motor Corp.'s North American chief, preparing to sell Camry-sized hydrogen sedans next year, said he's "bullish" about advances in the company's fuel cell system and wants more U.S. supply of the Japan-built cars.

Toyota, the world's largest seller of hybrid-electric autos, is to sell the as-yet unnamed four-door model in California in 2015, as well as in Japan and Europe. Its performance, packaging and other attributes will generate demand for the car, North American Chief Executive Officer Jim Lentz said Thursday, without providing a sales goal.

"After we've seen the product, understand its range, its driving dynamics, its refueling, we're a lot more bullish than Japan — probably about fivefold more bullish," Lentz said in an interview at the Wall Street Journal's ECO:nomics conference in Santa Barbara, California. "It's just a question of how many can be produced now."