A private-public investigation team has found that the main cause of the recent BMW car fires is not the “exhaust gas recirculation (EGR) bypass” problem as previously claimed by BMW, but faulty “EGR valves.”
The Korea Transportation Safety Corporation (KTS) announced the findings of the investigation team on Nov. 7. The team's findings suggested there could be other fire-catching elements, raising the possibility of additional recalls.
The team, consisting of experts from the public and private sectors, carried out experiments to determine the cause of the manufacturing defect in relation to fires. It found that BMW vehicles catch fire when the following three conditions exist -- when there is a leak in the EGR cooler, when the EGR valve is partially open and the car drives at a high speed, and when the exhaust gas aftertreatment system (DPF/LNT) is in operation.
In this state, a fire was started as the high-temperature exhaust gas was supplied to the precipitates and particulate matter (PM) which were accumulated in the EGR water cooler through the EGR valve. The sparked ember was adhered to the intake system and resulted in a fire due to the inhaled air.
This finding is different from the explanation given by BMW Korea in August. At that time, the company cited the opened EGR bypass valve along with continuous high-speed driving, EGR cooler leaks and cumulative driving distance as the causes of the fires.
However, the investigation team confirmed that the EGR bypass valve opening has nothing to do with the fires but emphasized that faulty EGR valves, which BMW had not mentioned, were the main cause.
"These results mean that there could be other elements that cause fires in BMW vehicles besides those cited by BMW," the team said. The investigation team will announce the results of the final investigation report next month and plans to recommend follow-up measures to the Ministry of Land, Infrastructure and Transport if further action needs to be taken.