DEARBORN, Mich. — Ford Motor Co. reported its third consecutive full-year profit Friday and its largest in 13 years, ensuring its hourly workers one of the biggest profit-sharing bonuses in the company’s history.

Ford said strong sales in North America overshadowed higher commodity costs and losses in other parts of the world. The North American results mean 41,600 U.S. hourly workers will receive $6,200 in profit-sharing bonuses for 2011, up from $5,000 the year before.

Ford made an unusual accounting adjustment in the fourth quarter worth $12.4 billion that increased its 2011 earnings to $20.2 billion, the second-highest total ever for the carmaker. But excluding that one-time gain, Ford’s fourth-quarter operating profit declined.

The accounting change eliminated most of a tax allowance created when the company was bleeding billions of dollars in 2006 and saw little likelihood of making a profit in the coming years.

By making the adjustment, Ford is now signaling that it expects to continue earning substantial profits.

“It’s a very positive signal,” said the company’s chief financial officer, Lewis W.K. Booth. “In our judgment, we’re going to be profitable enough in the foreseeable future to use up the deferred assets.”

The hourly workers received a $3,750 advance on the 2011 bonus after signing a new four-year labor agreement last fall and will receive the remaining $2,450 in March. The largest profit-sharing bonus at Ford came for the year 1999, when workers received an average of $8,000.

The accounting gain means that, on paper, Ford has recovered nearly all of the $30.1 billion it lost from 2006 through 2008. In the three years since, the company’s profit totaled $29.5 billion.

Ford created the tax allowance in 2006, when Alan R. Mulally, the chief executive, joined the company as its performance was in a downward spiral and it mortgaged most assets to raise money. The losses meant Ford could no longer keep many deferred tax assets on its books, but after posting 11 consecutive profitable quarters, it was able to release nearly all of that allowance.

Doing so lets Ford offset taxes on about $35 billion of future profits, said James Hines, a law and economics professor at the University of Michigan.

“You would only do that if you were expecting a lot of pretax profits,” Hines said. “It’s not a shock, given how well they’ve been doing.”

By region, the company earned a pretax operating profit in North America in 2011 of $6.2 billion but lost a total of $119 million in its Europe and Asia-Pacific-Africa regions. Its fourth-quarter loss in Europe nearly quadrupled to $190 million, from $51 million in 2010, and Booth conceded that Europe “may stay challenging for some time.”

In contrast, North America, the epicenter of Ford’s past troubles, has become “the engine for supporting our growth worldwide,” Mulally said.

The net profit was equal to $4.94 a share, up from $1.66 a share a year earlier, when Ford earned $6.6 billion.

Excluding the accounting change and other special items, Ford earned an operating profit of $8.8 billion for the year, or $1.51 a share, 6 percent more than its 2010 operating profit of $8.3 billion, or $1.91 a share.

Revenue increased 13 percent to $136.3 billion, but profit margins declined to 5.4 percent, from 6.1 percent in 2010.