IMPROPER REVERSE ENGINEERING

by
Charles C. Roberts, Jr., Ph.D., P.E.

Reverse engineering is the processes of designing a product that operates like a competitorís product without the benefit of having drawings or other in- formation on the competitorís product. Reverse en- gineering is often employed in an attempt to avoid patent infringement. Automotive remanufactured parts suppliers have been known to utilize reverse engineering in order to reduce costs of rebuilt auto parts.


Figure 1


Figure 1 is a photo of a vehicle that was at the ori- gin of a fire in a garage that was badly damaged and a relatively large property loss. Burn patterns (1.) traced the fire origin to the alternator shown in Fig- ure 2. There was unusually severe melting of the al- ternator housing near the rectifier unit, suggesting that an electrical malfunction had occurred in the al- ternator, causing the fire. Since the vehicle was parked and had cooled down, other potential causes of the fire were eliminated. The original alternator had recently been replaced with a rebuilt alternator by a garage mechanic near the insuredís home.


Figure 2


Figure 3 is a simplified drawing of a typical auto- mobile alternator. The engine turns a belt driven pulley, which turns the rotor shaft supplying electri- cal energy to the battery and other electrical com- ponents. The brushes, which transfer electricity from the rotor shaft, wear over time and are re- placed during rebuilding of the alternator. The recti- fier, an electronic component, converts the alternat- ing current to direct current and is a part that is of- ten replaced during rebuilding.


Figure 3


Detailed inspection of the alternator yielded evi- dence that the fire started in the rectifier assembly. According to the rebuilder, the rectifier assembly was replaced with an aftermarket unit as part of the remanufacturing operation. The aftermarket rectifier did not conform to the original equipment manufac- turerís specification. In fact, it was discovered that the rebuilder was not authorized to refurbish alter- nators by the original equipment manufacturer. The rebuilder did not perform any reliability testing or sampling of the product for quality control pur- poses. The rebuilder merely reverse engineered the rectifier assembly by matching an off the shelf unit with the expected output of an original equipment manufactured rectifier. Typically, original equipment manufacturers au- thorize rebuilding of automotive components as long as certain specifications are met. Specifications include reliability testing, performance testing and sample testing of a certain percentage of rebuilt units. If a rebuilder remanufactures product with- out following original equipment manufacturerís specifications and without any alternative reliability testing, then there is a high probability that the reli- ability of the unit will be substandard. The particu- lar rebuilder of the alternator in Figure 2 had ex- perienced a very high premature failure rate with customers.


Figure 4


Additional inspection of the alternator revealed an improperly assembled brush as shown in Figure 4. The right (red) arrow points to an alternator brush that was in good condition. The left arrow (black) is the other brush that was sheared in half, a result of improper assembly of the alternator. Although this defect did not directly cause the fire, the alternator would have failed much earlier than expected. This attested to the degree of substandard workmanship performed by the alternator rebuilder. It is apparent in this particular case that the reverse engineering of the rectifier assembly was substandard and lead to the malfunction that caused the loss. The alternator rebuilder eventually settled with the insurer of the automobile and garage.

1. ďAutomotive Vehicle Fire Analysis,Ē Charles C. Roberts, Jr. Ph.D., P.E., Roberts Publishing, 2004.

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