Honda Motor Co. unveiled a hybrid engine system and lightweight aluminum body structure Tuesday for a new car to be released this fall that the automaker claims will achieve the world's lowest fuel consumption among mass-produced gasoline-powered vehicles.

The fuel economy of the two-seater Insight is 35 km per liter, which allows the car to run more than 1,000 km without refueling, Honda officials said.

The hybrid system, named Integrated Motor Assist System, consists of a 1-liter lean-burn gasoline engine, an electric motor and batteries.

The electric motor assists the engine during acceleration and also serves as a generator during braking for optimal use of energy, the company officials said.

The exhaust gas is 50 percent cleaner than required by government regulations that take effect next year, Honda claimed.

The main rival of Insight is expected to be the Prius, the world's first hybrid car, released by Toyota Motor Corp. in December 1997.

The five-seater car, similarly equipped with a 1.5-liter gasoline engine, an electric motor and a battery system, boasts fuel economy of 28 km per liter.

A number of automakers, including Nissan Motor Co. and Fuji Heavy Industries Ltd., have recently rushed to develop a hybrid car seeking better fuel efficiency and cleaner exhaust gases.

The body structure of the Insight also adopts aluminum materials processed through extrusion, a method that forces hot aluminum through a die under extremely high pressure.

Honda's extruded aluminum body is 40 percent lighter than a typical steel body and thus greatly improves the fuel efficiency of the car, Honda said.

Honda became the world's first carmaker to market a mass-produced all-aluminum car when it released the two-seater sports car NSX in 1990.