PARIS — Volvo Car Corp. will introduce a diesel hybrid in 2012 if not sooner, while start-stop technology will arrive in 2009, company executives said here at the auto show.

The hybrids will be sold in Europe and the United States.

The start-stop technology, which turns off the engine at stops, will be introduced on Volvo's smaller cars, such as the C30, S40 and V50. Later, start-stop will be spread to the rest of the lineup.

Diesel hybrids will appear first in the larger sedans, crossovers and SUVs.

Volvo's hybrids will be able to operate on battery power alone at low speeds. In the Volvo system, the front wheels are driven by a variant of Volvo's five-cylinder turbodiesel, while the rear wheels get a separate electric motor.

A plug-in variant will come "very quickly" after the initial hybrid arrives, said Magnus Jonsson, Volvo's senior vice president of r&d. Plug-ins use household current to recharge the battery, reducing the need for gasoline or diesel fuel.

Diesel engines and electric motors have an inherent shortcoming: Both have ample low-end torque but lack high horsepower at high rpm. Nevertheless, the combination makes the most sense for reducing carbon dioxide emissions, said Lex Kerssemakers, Volvo senior vice president of brand, business and product strategy.

Volvo also is studying whether to stop using V-8 engines in favor of turbocharged six-cylinder engines on its high-end models, Kerssemakers said.

"I don't think there is a bright future for the V-8, especially for Volvo," he said. "It's the best engine we have. But if the environment is changing, you can be stubborn, or you can look for alternatives."