Type of Atkins cycle for helping GDI carbon on intake valves?

[DriveHard]

Just thinking in the shower again...

In a type of the Atkins cycle, the intake valve is kept open during the start of the compression stroke, and some of the intake air is pushed back into the intake. If one were to do this on purpose, and spray fuel in during that time, could it wash over the intake valve and help keep it clean? That fuel would then vaporize in the intake manifold for use in the next cylinder's intake stroke?

Just thinking out loud...

Atkinson cycle - Wikipedia

en.wikipedia.org

 

[Boomer]

I think you may be on to something. I once suggested on here that GDI engines would benefit bone of those water injectors that folks used to use on their engines except that it would be filled with Techron or some other PEA containing liquid that would be slowly pulled through the intake and over the intake valves.

 

[OneLonelyBurrito]

While that would help keep the intake valves clean, I can't imagine how hard it would be to accurately control the amount of fuel that is going back into the intake track. With how tightly A/F ratios need to be controlled, I can't imagine a manufacture want to implement something like that just to keep the intake valves clean. It would probably be easier just to better control the amount of oil slipping past the intake valve guide seals.

 

[Pablo]

Tacoma 3.5L V6 supposedly has this....cannot say if for real and how effective.

 

[Pew]

Ford does this with their 3cyl 1.0 engine, but do you mean you doing this (like spraying a bit of gas directly into the intake manifold) instead of the engine doing it?

 

[Jetronic]

I think you may be on to something. I once suggested on here that GDI engines would benefit bone of those water injectors that folks used to use on their engines except that it would be filled with Techron or some other PEA containing liquid that would be slowly pulled through the intake and over the intake valves.

Fit a pneumatic oiler with pea containing liquid on the pcv hose

 

[Jetronic]

While that would help keep the intake valves clean, I can't imagine how hard it would be to accurately control the amount of fuel that is going back into the intake track. With how tightly A/F ratios need to be controlled, I can't imagine a manufacture want to implement something like that just to keep the intake valves clean. It would probably be easier just to better control the amount of oil slipping past the intake valve guide seals.

doesn't matter as you have a MAF sensor telling you exactly how much fuel you need, it all evens out.

 

[fsdork]

I would be curious about the effect of contaminates being pushed out of the cylinder and into the intake or beyond. Do they make it to things like the MAF sensor, IAC, variable intake runners, etc? Does the solvent action of the fuel result in a net cleaning effect?

 

[Pablo]

I THINK you mean Atkinson Cycle

https://www.cars.com/articles/engine-deep-dive-toyota-tacomas-atkinson-cycle-v-6-454806/

 

[SC Maintenance]

Holding the intake valve open longer would effectively shorten your compression stroke, taking away part of your compression ratio and a lot of your efficiency.

Any efficiency gained by the GDI in the first place just want up the intake hole

 

[sloinker]

Better designs incorporate direct injection as well as port injection. You are seeing this more and more as manufacturers learn from their mistakes and adopt it for their new models. Methanol injection sounds like a good idea if the air/fuel management systems will tolerate it without causing other issues or faults.

 

[bobdoo]

Holding the intake valve open longer would effectively shorten your compression stroke, taking away part of your compression ratio and a lot of your efficiency.

Any efficiency gained by the GDI in the first place just want up the intake hole

Mazda does this. You get a larger effective power stroke, in comparison to intake.