Nooo, he didn't. And to further burst your bubble, the term "crap" was around long before Crapper was born...it actually means the husk of grain or chaff, residue from boiling fats, dregs of beer making...etc. WWI soldiers brought it to America
Maybe, maybe not.
Siphonic flush toilet
Crapper's Valveless Waste Preventer
Crapper held nine patents, three of them for water closet improvements such as the floating ballcock, but none was for the flush toilet itself.[citation needed] Thomas Crapper's advertisements implied the siphonic flush was his invention; one having the text "Crapper's Valveless Water Waste Preventer (Patent #4,990) One movable part only", but patent 4990 (for a minor improvement to the water waste preventer) was not his, but that of Albert Giblin in 1898.[7][8] Crapper's nephew, George, did improve the siphon mechanism by which the water flow is started. A patent for this development was awarded in 1897.[9]
Origin of the word "crap"
It has often been claimed in popular culture that the slang term for human bodily waste, crap, originated with Thomas Crapper because of his association with lavatories. A common version of this story is that American servicemen stationed in England during World War I saw his name on cisterns and used it as army slang, i.e. "I'm going to the crapper".[10]
The word crap is actually of Middle English origin and predates its application to bodily waste. Its most likely etymological origin is a combination of two older words, the Dutch krappen: to pluck off, cut off, or separate; and the Old French crappe: siftings, waste or rejected matter (from the medieval Latin crappa, chaff).[10] In English, it was used to refer to chaff, and also to weeds or other rubbish. Its first application to bodily waste, according to the Oxford English Dictionary, appeared in 1846 under a reference to a crapping ken, or a privy, where ken means a house.[10]