Direct Injection PSI Variation Across Engines?

[JExpedition07]

Curious on the Direct Injection pressures. The 3.5 EcoBoost is 150 Bar/2150 psi, the 5.0 V8 is 200 Bar/3,000 psi, the 2.3 EcoBoost is 5,000 psi. The new Ram Hurricane is 350 Bar/5075 psi.

Whats with the wildly differing values? It doesn’t seem to coincide with N/A vs F/I since the 5.0’s injectors are jetting fuel into the cylinder at higher pressure than the 3.5 EB. But then the Hurricane is 2,000 psi more than the 5.0. Interesting.

Anyone knee deep into fueling systems know why DI values vary so much across ICE engines? I thought they’d be similar, not the case at all. Feel free to move a more appropriate section if need be. Don’t know where to place such a discussion.

Sponsored

 

[powerboatr]

Out on limb
Maybe it's related to actual cylinder displacement.
Or something with placement of injectors, in relation to valves and piston head shape and size.
Which of those use same pistons?


It is odd imo that pressures are so far apart.

 

[FI300]

Just guessing but I would think it has more to do with the injector design and the amount of fuel they want to flow through the injector. Cylinder pressures are not that high that I would think this has anything to do with cylinder pressure.

 

[Pedaldude]

Aside from looking at engineering papers and seeing if there’s any data correlation for increased DI pressures, for bore size, cylinder pressure, flame front, or other variables like perhaps fattening the sweet spot on the brake specific fuel consumption map.
My wild ass guess is that it’s institutional inertia and that since the DI 3.5 ecoboost came out in 2011 and it wasn’t until nearly a decade later in 2018 that the Coyote received DI that higher pressures were more easily attainable at a price point Ford was comfortable with and since all of the engineering R&D had been paid for on the Ecoboost; Ford won’t reinvent the wheel for a feature that the average consumer could give less than a shit about.

Since it’s a niche subject, I would do very specific assumptive searches like “direct injection pressures effects on flame front.” rather than a general search for what the differing pressures are accomplishing. Since again, guessing the engineers themselves are still figuring it all out.

https://www.sciencedirect.com/science/article/abs/pii/S1359431122007876

Sponsored