NOTE: If you're intimidated by all of this math, or simply don't care about these formulas, that's fine. But please skip down to the last paragraph.
We could go down an entire rabbit hole here with this. Diagram looks correct, save for
y should be down on the throttle plates (and there should technically be two of them in case the butterflies are either out of sync or one is leaking, or more specifically
y to represent the sum of both butterflies with each having it's on representation within a sub-operation), and where you have
y, that should be
n to represent the sum of all metered air flowing through.
With the idle speed screws, there is a relation to all 3 screws, which is why I wrote the formula the way that I did (which bear with me, my math is a bit rusty), and even then it's probably oversimplified and incorrect unless we want to really get into the weeds on that one. Include the first screw as a way to represent the initial air flow that must be presented to the left & right cylinder bank screws. If it's zero, then everything is zero. If it's open, unless the other screws are open, it's value remains at zero. Once a screw is open, then the screws will only take as much as they're allowed until their metering exceeds that of what the initial screw can provide. If flow is restricted on one side, then the opposite side would take up the unclaimed CFM so long as the first screw can provide it. Which going back to the previous example, if the first screw was cracked to provide 6 CFM and each screw was set to only accept 3 CFM, then we're balanced. But if we increased the opening on the first screw, then the restrictions on the second screws would still only pull 3 CFM each. Assuming of course that we actually got the screws to be that accurate. Given that BOSCH introduced that balancing tube, I seriously doubt they believed most mechanics could ever have the level of accuracy in balancing cylinder banks. Thus the original system was designed to be self-correcting. But like I say, those latter values are intended to be in relation to the first, and we ought to include the flow rate of that first screw if we really want to nail it down.
Then considering the prior formula, perhaps we should look at that again. The fuel flow rates inside of the fuel distributor may not actually be linear in relation to engine demand. They may only be proportional to air flow instead, which means we might actually have
f ∝
n
f itself isn't simply an independent value. That is the entire sum of another formula, whereas both formulas are also influencing and affecting one another. Within A:F we've only looked at the A portion.
x,
y, &
z are all items which we have control over (be it purposeful manipulation or automated control by the on-board systems).
v was intentionally kept separate as it is the wild card that cannot be controlled, and is practically incalculable due to the sheer amount of variables involved with it.
The value of v should always be irrelevant, because the goal should always be to eliminate it and never to accommodate it. Hence why I look down on just disconnecting LAMBDA to solve an issue, but I digress...
With
f it has multiple inputs to define it's sum. Which at just a quick glance would include, but not be limited to:
- Fuel pressure from pump.
- Line pressure set by the primary pressure regulator
- WUR line pressure.
- LAMBDA modulation.
- Manifold vacuum.
- Fuel flow rate.
The list here goes on. But even then we have yet another formula we've not spoken about. On an internal combustion engine, combustion is the key word. The three things fire needs to occur? Air, Fuel, and Heat. A:F is no good without Heat to ignite the fuel mixture. Heat comprises both the cooling systems & ignition systems for not only their proper functions, but how they also affect the individual components of both the metered air
n and metered fuel
f given that temperature affects the baselines of components within those individual systems such as the ISM & Frequency Valve since Idle & LAMBDA have preset values that are temperature-dependent. So we have 3 formulas,
A, F, &
H which are all interacting with one another!
Last Paragraph.
Now for anyone intimidated by this, or who just doesn't care about the math, this is for you. While this has been a fun little exercise here, the point is that these formulas have always existed. Believe it or not, whenever you're troubleshooting something you're actually performing algebra. Algebra is the fundamental bedrock of troubleshooting. Now I'm not picking on anyone in particular, let alone any DeLorean owners. But far too often whenever someone has a problem, they want someone to tell them what to replace without performing any troubleshooting. I fully believe that a big part of that problem comes from weak mathematical skills which makes the troubleshooting process far too intimidating. Down below I'm going to give an example of a diagram of a simple flashlight. It contains both a schematic, as well as a pictorial diagram of a flashlight (or torch if you're from the rest of the world). The components of the circuit within the schematic tells you in what order the components would be, and the pictorial shows you what they look like and/or their physical location in the real work. Now, what is the goal of any flashlight? To product light of course! So now that you know what the purpose of this device is, you now know what it's desired sum is. And the components of the circuit become components of the formula. So a functioning flashlight should have a mathematical expression of
Charged Battery+Positive Wire+Closed Switch+Second Positive Wire+Light Bulb+Negative Wire=Light Now think about what you'd do if you had a flashlight that didn't work. What would you do to troubleshoot it? And BINGO! You're using algebra to troubleshoot.
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