I know all the differences between diesel and gasoline engines and can tell the difference in sound a block away. However, I cannot explain why they sound different. What exactly are we hearing when we hear that distinctive clatter? Is it the sound of higher compression? That doesn't seem likely since higher compression gasoline engines don't change their sound very much. Could it be the sound of compression ignition? Probably. When a gas car 'diesels', it does sound like a diesel.
Why is this sound so distinctive and different than spark ignition?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13