A record number of papers will be presented at this week's engineering conference on ways to improve fuel economy and engine performance. The average fuel economy over the past few years has stayed stagnant at 20.8 miles per gallon among all 2004 models, which is below the 1988 high of 22.1 mpg. Much of the new research includes advances in gas-electric hybrid engines, hydrogen-powered fuel cells and the use of lighter materials and gains in gasoline engines. The conference is attended by about 40,000 automotive engineers and executives to discuss advancements in automotive technologies. Yesterday GM showed a Cadillac STS loaded with a literal trunk-load of new electronics.