Ken Periman Problem solving, Thermal incident on a vehicle at the test track

Problem Statement Thermal incident on a vehicle at the test track

Initial investigation Moved vehicle to secure location Reviewed vehicle for source of heat Looked for burnt materials on the fire wall and around the engine compartment Found source of heat damage Found that incident started at the turbo oil line to turbo connection Began to remove turbo heat shield, turbo banjo connection and compressible washers Looked at washers under microscope to understand potential leak path. Issue was determined to be ignited by oil presence and high heat

Initial investigation It was identified that the copper crush washer was damaged, causing a leak path of oil

Initial investigation Bolt for oil line that has a hole pass-through for oil to transfer from the oil inlet line into the turbo body. Copper crush washers that when tightened down with the assembly will form a seal between the bolt, the oil inlet hose and the oil inlet hole at the turbo. Oil inlet line that is nicknamed "Banjo" as it appears like a banjo shape. This line is where the oil is transferred into the turbo.

Initial investigation Defect issue notice on suspect vehicle Oil Vapor Spray Due to the damage to the lower crush washer, there was a void that traveled the width of the washer. This provided an avenue for the oil to flow out into the vehicle compartment thus causing a mist of oil and thus catching on fire. Oil flows (Red Arrow) through the tube into the banjo fitting and then down the bolt through a hole in the bolt down into the turbo inlet. Normal flow of oil into the turbo

Investigation Results: Copper crush washer was damaged providing a path for the oil to escape and to spray as a mist on the turbo housing on the exhaust side. Oil will normally smoke under heat but when sprayed as a mist will ignite into flames under high heat. The cause was determined to be a stamping issue. The part, after being stamped, was caught in the ejector and was damaged by another washer ejecting from the process. A process audit of the sub-supplier found that they were performing a 100% leak check on every assembly but their settings were not verified to catch any leak issues.

Investigation Results Cont. A review of the PFMEA found that the supplier did not review this issue and update their PFMEA for this issue. Worked with supplier and built a “Red Rabbit” with a crush washer with a leak path in it and adjusted the leak tester to detect this issue. Requested supplier verify this every day for proper failure of leak tester. Requested supplier to audit their supplier for any improvements of their process to prevent any more of these issues. Copper washer supplier at our suggestion added vision system to inspect for damaged washers.