Quote:
Originally Posted by niky
And, as I was pointing out, you can run very, very lean AFRs with water injection because of the knock prevention. AFRs far in excess of 20:1 are achieveable with water injection (with proper injection timing and nozzle sizes).
Actually, with certain motors, you can achieve 22:1 at cruise under lean burn without water... but obviously, not under load. My motor would see 18:1 to 22:1 after retuning (and still making more power!). And that was without water injection. Merely fuel and ignition adjustment.
This is why you need to break down the effects.
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I KNOW the energy is derived from the gasoline. I have just been plucking IamIan's nose hairs. But, I can tell you this, I can run my engine much much leaner than you could tune your engine using any of your methods if gasoline and air is the only thing you are introducing into your cylinders. Add a measured amount of water, and maybe you can extend into the low 20s for air fuel ratios. But how about 26:1? Or 28:1? Have you ever run a gasoline vehicle that lean and yet provide enough motive force to even cruise at normal surface road speeds? I can, with just HHO. I can reach 35:1 AFR ( estimated )with sub combustible hydrogen addition ( <4% by volume ) and the addition of pre-combustion heat. So, what mechanism would you say is allowing this to occur? It can't be your normal tuning. You can't even begin to approach those levels unless you are running a set up like pgfpro is building - a setup that adds boost and turbulence. I used 20 - 22 as an AFR example because that is the area my little 3 cylinder hemi head engine starts failing. It depends on your target output of course, but it could hold the target load up through 19:1 AFR but it started falling off beyond that. At 22:1, the engine was miss firing. It did not matter what you would do with timing, or even with the addition of a more energetic spark system, it couldn't run smoothly and make the target torque. With the addition of HHO, it could make the target output with a dramatic decrease in timing. And the torque fall off was not as severe as expected up to the limit of the test ( 28:1 AFR ).
People seem to think I am applying some hocus pocus logic to all of this, but it is rather simple - the hydrogen addition, even at the seemingly useless amounts ( less than 4% by volume, hydrogen's lower combustion limit ) changes and accelerates the reaction rate of combustion. A small change, as you already know, means a reduction in the ignition lead time and a reduction in the wasted pressure before top dead center which works against you and reduces your BMEP ( brake-mean-effective-pressure). In the slow flame fronts of lean burn, this wasted pressure area is a significant percentage of the total.
So where does the energy to move the vehicle come from? The gasoline of course. At these levels of augmentation, the hydrogen heat contribution is very small. But by seeding the mixture before hand, there can be a domino effect of H+ ions knocking off more H atoms from the hydrocarbon chain to quickly become a significant part of the combustion mix leading to the process following the classic combustion studies for augmented levels above 4%. This is a simplification of course - a simplification to the point it is somewhat erroneous, but it serves to make the point.
I will extend the discussion of this process while attempting to make it presentable to the lay person in following posts.