Water cooled exhaust manifold = 20% fuel economy gain
 

Apparently Volkswagen has a turbocharged engine with a water-cooled exhaust manifold built into the cylinder head. They claim a 20% Improvement in fuel economy, substantially because of the water cooled exhaust manifold. The YouTuber "Engineering Explained" does a good job of narrating the design and the reasons for the claims.

https://m.youtube.com/watch?v=nNendiDFzSM

On start up, protect the catalytic converter.
Sounds like a cracked cylinder head.

Honda had this in the Insight 19 years ago. ;) I really wanted one of the K series engines which had a water cooled header (I believe they started in 2009) but it turned out to be impractical for my purposes.

Really enjoy Engineering Explained btw.

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I didn't know that, about the insight. Which k-series had it tha you considered impractical?

it is a favorite of mine. He is no mechanic, however. That's his only real limitation, as I see it. But he is precisely the kind of engineer I hold up to my engineering-interested daughter as a model: familiar with materials, processes, and wear as well as the math, software, theory, and design.

To my knowledge it was the 2009 Acura TSX and 2012 Civic Si that used the K24Z3 and K24Z7 respectively, and these were the first (high performance at least) K series with water-cooled and integrated exhaust manifolds.

The Insight shares a ton of wiring and sensor signaling with the RSX (2002-2004). It shares a bit less with the 2005-2006 RSX/2004-2008 TSX which moved to drive-by-wire. It shares progressively less with newer ECUs and engines, and the farther forward you go, the more incompatibility you get.

The 02-04 RSX ECU which I chose due to extremely close compatibility with the car's body systems can in theory be used to run any KxxA or KxxZ engine, but a lot of parts and sensors need to be taken from earlier engines to run the later ones, such the crank position sensor, which has very different wiring, and to run the TSX engine I chose I already had to retrofit the throttle body from an earlier-year Accord plus repin most of the other sensors.

The other alternative is to use the correct ECU and wiring harness for the engine, e.g. 2012 K24Z7 ECU with 2012 K24Z7 engine, but then you have issues with things like incompatible body electronics - EVAP/emissions systems, all of the gauge cluster signaling, need to retrofit drive-by-wire to the pedal, and who knows what else. Fuel pump? Haven't the faintest idea if it would work.

Anyhow, I digress. I'm sure someone else the integrated header even before Honda, but the Insight's is the earliest engine I'm aware of.

The complexity of such swaps is like cold water on the imagination.

I've contemplated multiple times brazing soft copper tubing to my exhaust manifolds and plumb coolant to them to help speed up warm up times. I think on short commutes you could definitely see up to a 20% increase in fuel economy from faster warm up times. However, then you have to handle the constant input of that additional heat into the cooling system. That means a larger grill opening, larger radiator, and thus larger aero penalty. Overall, I definitely think its a win, but it would be so nice if we were able to find a way to turn it off like Toyota does with its exhaust heat exchanger on the Prius.

I would be careful of overheating your coolant. This has been a problem since the water cooled egr coolers started in 2004 on the Diesel trucks. The International produced engines used in Ford and International trucks have problems overheating the coolant and plugging the engine oil coolers. Almost all the light duty Diesels have egr cooler failures that lead to coolant consumption.

My Insight 3 cylinder had problems staying warm, not cold, even with a water-cooled exhaust.

If one were able to shoot hot steam at some part of the engine to warm it up, which would be the best location?

how can something be welded to an exhaust manifold?

Would a brazing rod work to attach some copper or stainless pipe? Or would it melt off?

Exhaust
 

FYI /FWIW

Although, VW and the Toyota are the top two world wide automotive manufactures. VW has shown pathetic corporate governance. Water cool exhaust has been used on many diesel marine application with terrific results. VW has corporately stated they will be ICE free in some future day. Sadly VW had not problem in misleading the worldwide consumers about clean diesel. VW and Honda have had some impressive engineering and technology concepts sadly and reality and corporate mindsets have not allow much of them to see the light of day.

My guess is the oil pan.

A jacket around the oil cooler?

Honda's oil warmers/coolers are a water jacket that sits between the oil filter and the block, actually. Since coolant heats up more quickly than oil, it helps bring the oil up more quickly. I hope to add one to my current engine.

VW couldn't even get rid of naturally-aspirated engines, as it was aiming to do 16 years ago :turtle:

My Si has the exhaust manifold integrated into the block. I can get 48mpgUK (40 mpg US) pretty regular in the summer.

Great video. Thanks for link. Now I want an Alltrack TSI.

The rising European death rates due to increasing diesel particulates & emissions were telling the true stories. But, most people believed, "Dead men tell no tales".

It's becoming an issue with gassers too, because of direct-injection becoming widespread on them, to the point that a particulate filter becomes mandatory for gasser versions of certain models too. The current-generation Mercedes-Benz A-Class is available in my country only as a gasser, but it's now fitted with particulate filter.
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https://1.bp.blogspot.com/-9DDKi5XiO...o-esquerdo.jpg

I wonder if direct-injection gas engines are more efficient enough to justify the addition of particulate filters? Otherwise, why not just go back to indirect injection gas models.

Or, perhaps the direct-injection gas engines don't produce enough particulates to make adding a particulate filter the expensive and disruptive mess that diesels are having to contend with nowadays.

It's not just about direct injection, it has also something to do with enabling a leaner burn on higher-compression engines.


Since the fuel for a gasser or a flexfuel is more volatile, the particulate matter emission might remain less troublesome. What might also influence is the fact that gassers might resort more frequently than Diesel engines to some fuel enrichment in order to decrease the NOx emissions, at the cost of higher PM levels...

Ah, rich Mercedes saw that criminal air pollution conduct by VW didn't put any VW officials in jail. So other methods of polluting the air are..... "good to go".

I've heard that burning 100% ethanol-free gasoline (E0), instead of 10% ethanol blends, helps reduce deposits in DI engines. Might the use of E0, instead of 10% ethanol blends, also reduce particulate air pollution?

I'm not so sure about it, but it doesn't seem so likely.


I'd also not hold my breath for that. Even though ethanol may be harder to fully vaporize on port-injection engines, with DI it has been possible to avoid pre-heating of the fuel as a cold-starting aid. Trimming the AFR a little leaner at the cold starts might help to decrease the PM emissions in a worst-case scenario.