Diesels are really efficient; giving approx. 10-25% better
mileage than a similar gas engine of the same size.
However, due to the heterogeneous nature of the fuel introduction in the cylinder, the exhaust gets rather smoky
as the air fuel ratio nears stoichiometric.
(In other words, as the fuel burns as it comes out of the injector, the last bit of fuel dosent have as much oxgen as the first bit did, so the fuel is reduced to carbon…soot.)
True, you could increase the amount of oxygen by using blowers or turbos, but could you make the fuel delivery more heterogeneous by using two ore more injectors per cylinder?
After all, some gas engines use two spark plugs per cylinder, like top-fuel dragsters, some Porches, and the Ford OHC four cylinder they had in Ranger pick-ups and Turbo Mustangs.
Well the diesel engines I’ve seen are pretty large, around 3MW or around 3500 horsepower with 16 cylinders, each piston must be around 16 inches across and it takes two to lift one conrod with the piston and gudgeon pins fitted, and its still a heavy lift.
Given such a large volume yo would think that this would be a primary opportunity to have multiple injectors but they don’t, they do have turbos and intercoolers.
It might be that if two streams were to interact from differant inectors there would be a chance of the sprays amalgamating fuel droplets resulting in a poorer burn.
The injectors do have multiple holes though so maybe this is the closest equivalent.
These are what one would call a trifle noisy to be around, the noise is so great it makes the air in the chest cavity vibrate along with the breastbone.