London: Renault have had to scrap Nick Heidfeld`s car that caught fire at last weekend`s Hungarian Grand Prix, the Formula One team said on Thursday.
Team technical director James Allison said several incidents combined to cause the blaze, including running a slightly different engine map in qualifying, which produced hotter than usual exhausts.
"We believe that this elevated temperature and caused a preliminary crack in the exhaust pipe," he told the team website.
The pitstop during the race then took longer than normal with the engine revving and temperatures rising, finishing off the exhaust pipe and starting a fire.
A subsequent explosion in the car`s sidepod, after Heidfeld had parked up on the grass verge and leapt out, was caused by an air bottle supplying air valves in the engine, Allison explained.
"The incident was highly undesirable, as it has caused us to write off a chassis. We will take steps prior to the next race to reduce the likelihood of a further fire and to ensure that the air bottle cannot overheat," he added.