PSA Peugeot Citroen is spending 315 million euros ($US314 million) to double production of small diesel engines for its Peugeot 206, Citroen C3 and Ford's Fiesta and Fusion lines at a plant in Tremery, France, reports said. PSA has added 300 workers for the new assembly line, which will make 2,500 1.4-litre engines daily.