DETROIT (Reuters) -- The head of the American unit of German autos parts supplier Robert Bosch GmbH said he expects U.S. light vehicle sales to improve to 11 million units in 2010, indicative of a steady but slow recovery from a bottom reached earlier this year.

Overall auto sales will end 2009 near 10 million units, which would be a decline from 13.2 million units in 2008 and 16.1 million in 2007.

The last truly good year for U.S. sales for Bosch was 2007, when they were at levels that will not be seen until 2012, Peter Marks told the Reuters Autos Summit in Detroit.

For Bosch, 2010 will show increased sales, "but it will take us until 2012, Bosch as a whole, to get the sales again what we had in 2007. That is quite a long road," Marks said.

"The recession has impacted Bosch significantly," Marks said. "For 2009, we expect worldwide sales to fall by 15 percent, to $51 billion. For the automotive (unit at Bosch), the decline is even worse -- by 20 percent worldwide and by 21 percent in North America."

For the rest of 2009, he said, "The fourth quarter will be better than the fourth quarter of the previous year but it will be still 20 percent below what we experienced in a good year, which is our reference, 2007."

Bosch will spend about $4.2 billion worldwide on research and development, which Marks said will keep it competitive in the emerging alternative vehicle market.

"For the auto industry, all roads ultimately lead to the full electrification of the vehicle," Marks said, adding that it will take two decades for alternative vehicles to overtake the internal combustion engine.

He said Bosch, which makes a wide array of products in addition to auto supplies, is positioned for the coming changes in powering autos because it is established in Europe where small cars make up a larger share than in North America.

Bosch over the next three years expects to increase U.S. sales at an annual rate of 7 percent to 8 percent, "which is a pretty good growth in a mature market," Marks said.

Bosch ranks No. 1 on the Automotive News list of the top 100 global suppliers, with estimated sales to automakers of $33.9 billion in 2008.