Ransom
Ransom GRM+ Memberand PowerDork
1/14/17 7:06 p.m.

Aw, man, I've done it again: TL;DR; Give me your links and book recommendations on modern engine management.

We have some folks here who know a lot about this, but I'm not going to ask anyone to type of the combined wisdom of their day job for my benefit (or even the folks who don't do it professionally but know a bunch).

I'm wondering whether any of the many and varied books out there can be recommended for getting to terms with modern engine management. I've just ordered a copy of the Ricardo book for an improved grounding and brush up on the basics (I've tended to read a lot more about suspension than engines), but right now it seems like there's a lot that needs learning about how to deal with advances in engine management technology from the hobbyist standpoint. I pondered adding this line of questioning to my old car new engine thread but thought it deserved its own.

I've done a basic Megasquirt installation, and have the usual hobbyist understanding of the bits involved, the relationship between MAP and fuel pressure, the basics of the effects of rich and lean on making power, avoiding making too much heat, the slowness of a lean mixture, though there's a huge amount there I don't know. But that's all in the realm of port injection, and usually amateur application more or less boils down to "the rightish amount of fuel, with spark at a reasonable time" with a lot of variables left out as compared to a really modern engine.

How does one decide what to do with variable valve timing? Lift? I had a really fun time reading up on the Fiat MultiAir valve actuation system. It's exciting and interesting, but it also has modes of operation that I don't see understanding well enough (from where I'm standing, still looking for a giant with available shoulders) to implement even if I had an ECU capable of driving it (multiple intake valve lifts on one intake cycle!?). But the more I thought about it, the more I thought I could at least drive it well enough to take advantage of some of its capability in a street/autocross car.

So, what books can anybody recommend? Links? Sites? Forums?

And of course I'd love to see articles in GRM rounding up the current crop of ECUs and what they're capable of, and would REALLY love to see an article where you guys sit down with someone really current on production car engine management and update us all from the realm of fueling/timing/boost to include the considerations around direct injection pump control (how to determine timing? Is pressure just a faster, higher pressure and more complex version of the FPR issue of maintaining a constant pressure differential across the injector?), the effects of controlling valve lift and timing (to some extent it's like a review of cam profiles and what they do, but with the ability to tweak some parameters on the fly, with knock-on effects on others, of course...)

This is the new normal, right? Let's go!

alfadriver
alfadriver MegaDork
1/14/17 10:01 p.m.

For the most part, all of your answers can be said that months and months of dyno testing, you end up with a "if you want torque X and engine speed Y, where the conditions are the engine is Z temp, the air is A temp, then set the cams C, spark timing D, and throttle E. If the engine has variable valve lift, then substitute lift for the throttle- it does the same thing.

That's really it. Just a LOT of data that is mapped for all of the settings. The more stuff, the longer it takes to map it. Where I have a tough timing fathoming the time it takes to map it- when you have electronically controlled valves- where lift, open timing and closed timing are all variable.

I know that sounds long and tedious, but that's how we do it.

Fuel is easy- in the above- you estimate air flow via a MAF or the MAP, and inject fuel to be stoich, or a specific non stoich amount- and do it. Feedback is via the WB sensor and the second O2 sensor (yes, both). Probably 99% of the times, cars are running stoich or near that. Otherwise it's best fuel for torque OR fuel to cool the engine down.

There are a lot of functions that use all of that and output what the settings should be. IMHO, some of it is far too complicated given the simplicity of the inputs and outputs- but I can't be that specific....

A good question to ask- what is the INTENTION of a technology. And does it deliver that intention. For instance, breathing wise, intake VCT is generally all one needs. the exhaust VCT is there to control back flow- which is used to dilute the charge- it's basically EGR but cam controlled. Direct injection is there to cool the charge- allowing better breathing (cool the charge on intake stroke) and higher compression. It also has some cool side effects for better emissions- but that's normally only done for about 15 seconds.

Not sure if that helps... Or is what you are looking for.

Ransom
Ransom GRM+ Memberand PowerDork
1/15/17 12:28 a.m.

In reply to alfadriver:

Thank you. I'm going to read that carefully a few times, and I suspect a bit of research based on what you've mentioned there is in order. The gist of most of it seems clear, but there's a lot underneath.

It absolutely helps, and I'm working on getting to the point where I can understand just how much :)

But in any case, I very much appreciate it.

Off the cuff, it does suggest re: my other thread, that taking advantage of the tuning in a stock ECU is not to be sneezed at.

alfadriver
alfadriver MegaDork
1/15/17 9:52 a.m.

In reply to Ransom:

Off the cuff- absolutely, the stock engine management isn't to be sneezed at. Especially as more and more tech is added- I've posted that many times. I'm even leery of aftermarket "tunes" as I don't exactly trust their methodology in finding more power.

We had some tuners contact us after we finished a program and put it out for production- they were randomly changing stuff, not knowing that doing the wrong thing can easily blow up the engine- there were videos of people blowing their car up experimenting with the calibration.

I'm not totally against that, but the people doing the work really need to know what they are doing, and the real changes they are making. If they know- there's some power to be found, pretty safely. If they don't, it's easy to blow up the engine.

For aftermarket tuning modules- some of this can't be controlled yet. Others that can- but some of it, I'd do my best to replicate what the OEM tuned- like the VCT.

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