 Recognizing that the key to better performance of automobiles and airplanes was the improvement of fuels, he became interested in the catalytic processes used to convert coal and lignite to gasoline.In 1922, Houdry visited the United States, where he saw the Indianapolis 500, and toured a Ford Motor plant in Detroit, Michigan.On July 3, 1922, Eugene Houdry married Geneviève Marie Quilleret.