Water-cooled Exhaust Manifold = More Power, Less Emissions

integrated exhaust manifold

The future may be electric, but the venerable internal combustion engine still has a lot of tricks up its sleeve to help keep it relevant in the global marketplace. One of the most interesting new features to start showing up in recent years is this: the integrated exhaust manifold.

The basic idea behind this new exhaust manifold tech is pretty simple. You take the usual tubular exhaust manifold that’s bolted to the cylinder head of almost every internal combustion engine (ICE) ever created, and you take the head itself, and cast them out of a single piece. At the same time, a few clever water channels keep coolant flowing around the integrated exhaust manifold (IEM) to keep it cool.

 

Integrated Exhaust Manifold Cooling


That cooling liquid transfers heat from the exhaust to the rest of the engine. While a technology that increases engine heat may seem like the opposite of what you’d want in a performance engine, the warm coolant spreads across the block and gets the IEM-equipped engine up to temperature much more quickly than a conventional ICE. What that means for you is faster interior warmup times in winter, and better engine oil flow. That translates to better fuel economy, lower emissions, and vastly increased engine longevity.

If you’re smart, you’ve already dumbed that down in your head to “an integrated exhaust manifold makes cold starts pretty much go away”. If you think that, you’re right- but wait, there’s more!

To explain the integrated exhaust manifold and some of the gains tech like this can have in extended-range plug-in hybrids (vehicles that spend a lot of time in a “cold start” condition, in other words), the guys from Engineering Explained put together a great, 6-minute long video that explores the IEM found in the latest turbocharged Volkswagen engines. You can check that video out, below …

 

Engineering Explained | VW’s Water-cooled Exhaust


… then let us know what you think of the IEM’s potential to squeeze a few more percentage points’ worth of efficiency from the good-ol’ internal combustion engine in the comments section at the bottom of the page.

Source | Images: VW and Engineering Explained, via Jalopnik.

 

Jo Borrás

I've been in the auto industry 1997, and write for a number of blogs in the IM network. You can also find me on Twitter, at my Volvo fansite, or chasing my kids around Oak Park, IL.