Product names which are derived after an inventor's name will often remain capitalized, though not always (e.g. the petroleum distillate used to power trucks and locomotives is called "diesel" rather than "Diesel" even though it's named after the inventor of the four-stroke compression-ignition engine for which that fuel was formulated).
I suppose a more realistic example is the development of powered pumps, locomotives etc. Newcomen's atmospheric engine did a vital job, but was bettered by Watt's improvements. Trevithick's locomotive of 1804 hauled a load, but modern diesel engines work far more efficiently and reliably. // I'm not sure this is really an English language question.
insider.si.edu: Gas and petroleum engines; a manual for students and engineers, by William Robinson
Gas and petroleum engines; a manual for students and engineers, by William Robinson
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