Lotus Renault GP’s technical director James Allison revealed why Nick Heidfeld’s R31 caught fire during the Hungarian Grand Prix last weekend.
Video footage shows sparks flying from the left side of the car during Heidfeld’s pit stop. The left sidepod caught fire when Nick exited the pit lane. The German driver stopped his car at the end of the pit exit and jumped out of the cockpit. This was followed by a small explosion but the fire raged for some time before it was put out by the track workers.
Allison said that Renault has been forced to write off chassis 04. This is what happened.
“We run a slightly different engine mapping strategy in qualifying, which produced hotter than normal exhausts. We believe that this elevated temperature and caused a preliminary crack in the exhaust pipe,” Allison explained.
"We presume that the crack then propagated during the laps to the pit stop. We believe that Nick then came in with a partially failed exhaust. This pit stop took longer than normal, the engine was left at high rpm for 6.3 seconds, waiting for the tire change to be completed,” he continued.
"Under these conditions, a lot of excess fuel always ends up in the exhausts and their temperature rises at around 100°C/sec. This temperature rise was enough to finish off the partially failed pipe and to start a moderate fire under the bodywork."
Allison also provided an answer for the explosion. “This was caused by the air bottle which supplies the air valves in the engine. It has overheated in the fire and failed,” the technical director said.
Video footage shows sparks flying from the left side of the car during Heidfeld’s pit stop. The left sidepod caught fire when Nick exited the pit lane. The German driver stopped his car at the end of the pit exit and jumped out of the cockpit. This was followed by a small explosion but the fire raged for some time before it was put out by the track workers.
Allison said that Renault has been forced to write off chassis 04. This is what happened.
“We run a slightly different engine mapping strategy in qualifying, which produced hotter than normal exhausts. We believe that this elevated temperature and caused a preliminary crack in the exhaust pipe,” Allison explained.
"We presume that the crack then propagated during the laps to the pit stop. We believe that Nick then came in with a partially failed exhaust. This pit stop took longer than normal, the engine was left at high rpm for 6.3 seconds, waiting for the tire change to be completed,” he continued.
"Under these conditions, a lot of excess fuel always ends up in the exhausts and their temperature rises at around 100°C/sec. This temperature rise was enough to finish off the partially failed pipe and to start a moderate fire under the bodywork."
Allison also provided an answer for the explosion. “This was caused by the air bottle which supplies the air valves in the engine. It has overheated in the fire and failed,” the technical director said.