Nerd info about modern engine management

[Eskram]

While this is about how catalytic converters work, it's a good general overview of how the pcm manages the engine. Maybe someone will learn a thing or two...



Edit: Now with a working link!

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[XLT22]

Video doesn't work.

Ford should really take a cue from GM an invest in machine learning algorithms to run their engine management. It's one reason their V8s are so well behaved. And finally move the truck Ecoboost engines to MAF and get away from speed density.

 

[Snakebitten]

Doesn't Ford's approach to engine management on the 3.5 Ecoboost, using speed density, give them advantages with a turbocharged engine? (in contrast with normally aspirated V8 with much shorter intake)

MAF has lag, comparatively. Speed density gets faster and more accurate air/fuel ratio data.

I'm no expert, of course, but the gurus have always seemed to be pretty impressed with the Ecoboost engine management.

 

[Chris GTO TT]

Doesn't Ford's approach to engine management on the 3.5 Ecoboost, using speed density, give them advantages with a turbocharged engine? (in contrast with normally aspirated V8 with much shorter intake)

MAF has lag, comparatively. Speed density gets faster and more accurate air/fuel ratio data.

I'm no expert, of course, but the gurus have always seemed to be pretty impressed with the Ecoboost engine management.

As someone who's been around turbocharged engines for the better part of the last 25 years yes speed density is generally preferable to MAF on higher horsepower turbocharged engines. A lot of people spend a lot of money converting a MAF vehicle to speed density when they're trying to make more horsepower. MAF is generally more precise because it's measuring actual air flow whereas speed density is inferring it based on other parameters.

 

[XLT22]

Doesn't Ford's approach to engine management on the 3.5 Ecoboost, using speed density, give them advantages with a turbocharged engine? (in contrast with normally aspirated V8 with much shorter intake)

MAF has lag, comparatively. Speed density gets faster and more accurate air/fuel ratio data.

I'm no expert, of course, but the gurus have always seemed to be pretty impressed with the Ecoboost engine management.

SD/MAF decision is made so far up the product development timeline it's hard to give an easy answer. The answer to "lag" though is processing power and aforementioned machine learning algorithms hard coded into the PCM. The GM E90 PCM is pretty incredible in what it does now. I would have bought a 2.7 Silverado with my discount but you can't get that engine in a truck with a center console and I like being able to see over the hood. It's a great, smooth running engine. Ford does use MAF in other products and I've always wondered why they don't in the larger Ecoboost engines.

Speed density systems are all prone to some level of seasonal personality if you want to call it that. That can be down to how steps in the volumetric efficiency callups are done by the calibration team to meet targets for economy, CO2, NOx and so on. It's really my one gripe about them. In the end there's no real difference in fuel economy or drivability for the average consumer but it is a noticeable characteristic going to back to the throttle body injection days of the 1980s. The algorithmic approached used by GM, Stellantis, and so on improves the MAF system to the point where they essentially perform with no noticeable difference 12 months out of the year.

 

[Chris GTO TT]

While this is about how catalytic converters work, it's a good general overview of how the pcm manages the engine. Maybe someone will learn a thing or two...

Here the full link and video

 

[XLT22]

On the subject of cats, the next frontier so to speak is going to be the introduction of gasoline particulate filters in North America. Thankfully they're entirely passive and don't have to regen like the diesel stuff and haven't shown any reliability concerns overseas where they've been used for awhile that I'm aware of. The fine soot from direct injection gas engines is horrific for us to breathe so it's gotta be done. The larger particle size from carbureted and port injected engines was "less" bad since it tended to quickly fall to the ground funny enough.

The stuff I've seen so far is pretty compact. It won't be like the 80s and 90s where a V8 would have 4 cats stuck under it. The new stuff is catalyst coating on the GPF itself so it's all one unit.

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