stanislavz
Well-Known Member
Long story short. Diesels achieve~ 230-240 g/kw*hr bsfc in broad load range, where gasoline could achieve 300-330 g/kw*hr bsfc, in a narrower one. Where Prius engine could get it same or better as diesel.
Or like this one :
First and second generation Prius (Atkinson cycle) - 37% thermal efficiency.
Third generation Prius - 38% thermal efficiency.
Passenger car diesel engine (Diesel cycle) typical thermal efficiency ~ 34%.
Passenger car gasoline engine (Otto cycle) typical thermal efficiency ~ 28%.
And yes, you can put turbo on a Prius motor and get it from Atkinson to Miller cycle.
Cycle itself is just clever cam which does not close intake up to 70% of stroke is left. So we have less compression stroke, more expansion. And yes it is robbing power from engine too. So big and clumsy engine.
Same is one Diesel... And both of the do need a turbo to be viable in aviation uses.
Why not ? extra part to break ? need for efi which also over complicates all ?
On the other side we do have diesel with mechanical pump. Which adds some extra mass, but overall is a winner for slightly longer distances. Same as was suzuki conversion compared to two stroke rotax - yes, engines is heavier, but whole mass of load is lower for any longer mission.
Or like this one :
First and second generation Prius (Atkinson cycle) - 37% thermal efficiency.
Third generation Prius - 38% thermal efficiency.
Passenger car diesel engine (Diesel cycle) typical thermal efficiency ~ 34%.
Passenger car gasoline engine (Otto cycle) typical thermal efficiency ~ 28%.
And yes, you can put turbo on a Prius motor and get it from Atkinson to Miller cycle.
Cycle itself is just clever cam which does not close intake up to 70% of stroke is left. So we have less compression stroke, more expansion. And yes it is robbing power from engine too. So big and clumsy engine.
Same is one Diesel... And both of the do need a turbo to be viable in aviation uses.
Why not ? extra part to break ? need for efi which also over complicates all ?
On the other side we do have diesel with mechanical pump. Which adds some extra mass, but overall is a winner for slightly longer distances. Same as was suzuki conversion compared to two stroke rotax - yes, engines is heavier, but whole mass of load is lower for any longer mission.