Quote:
Originally Posted by Heavyd
Wouldn’t a design flaw mean that every LCI eventually will fail?
I did a testdrive with a 50e with some 10.000km and the dealer said they had no issues. I also saw no CEL  |
Hmm, if you are into industrial engineering a bit - assumption is every part may eventually fail, either within or far beyond its useful service life; what we evaluate is for a particular sample, when does it fail; and aggregate individual cases into a large sample pool, figure out what is the distribution of time of failure.
I do not have these aggregate data, so everything is just an example. In this case, we may see the probability this part fail prior to reaching 1000 miles is quite high - but it does not say every part will fail by then. Maybe some will fail at delivery, some fail around a few hundreds miles, some at a a few thousands miles, and some may never fail within its practical service life.
One simple example is light bulb - you can buy a knockoff one for $0.5 or a nice brand name one for $5. Both of them may fail within 10 year of usage; however you'd expect to see rate of failure at 10 year usage for $0.5 at much higher rate than $5 ones.
Regarding to if the problem is design vs. manufacturing, we really don't know. Say for example this part requires a 8kg/cm torque servo to operate correctly; if BMW made wrong calculation and decided to put a servo motor rated 6kg/cm here it is a design issue; if BMW calls for 10kg/cm servo but some bad batches were only in reality capable for <7kg/cm, then it is a manufacturing "bad batch"