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ShinerBock's avatar
ShinerBock
Explorer
Oct 20, 2020

Why diesels are most efficient around 1,800 rpm

Finally got more of an answer to why all diesels are most efficient around 1,800 rpm. In comparison to what I thought, it has more to do with how diesel burns than other things like compression ratio...
Tow Vehicles
valhalla360's avatar
valhalla360
Navigator
Oct 20, 2020
Actually, the bore and stroke work with the speed of fuel burn so that for our typical truck diesels, 1800 rpm is the sweet spot.

If you used a shorter stroke with a wider bore, so that you maintain the same compression ratio, the ideal RPM would in theory change.

Lots of small boat diesels are optimized for higher RPM. Yanmar LY hit peak torque around 2500 RPM.

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