Ford Motor Co. Chairman William ClayFord Jr. late last week defended the automaker's environmental record, including its decision to make the gas-guzzling Excursion, the largest sport utility ever built. Ford, an avid environmentalist presiding over his first annual shareholder meeting as chairman, said the world's No. 2 automaker does more than its competitors to produce cars and trucks that do not harm the environment. The company's factories are the cleanest in the industry, Ford said, and it has added equipment on many of its light trucks to qualify them as low emission vehicles.