Renault does not know why Sebastian Vettel has been the victim of multiple engine problems this year.
Four cars in the field are powered by the French manufacturer's V8, but it is 22-year-old Red Bull driver Vettel who was afflicted by two failures at Valencia last weekend, on top of his two problems earlier in 2009.
"There are no objective reasons why the problems have only been with Vettel and Red Bull," Fabrice Lom, in charge of Renault's customer engine programme, is quoted as saying by Germany's Auto Motor und Sport.
"The engines run in Red Bull with the same temperatures as they do in the Renault. And Vettel's style of driving doesn't have anything to do with it," he added.
