The document notes that this water jacket for the turbo also cools the aluminum wastegate and can be piped directly into the head. Alternatively, the coolant may be routed to and from another location in the engine, perhaps in an effort to keep a cool head and prevent detonation. It should be noted that part of the charge air line to an intercooler can also be cast in the head.
This idea has seen some development elsewhere. BMW’s turbocharged three-cylinder engine, the B38, features an aluminum exhaust manifold with an integrated turbo housing. It is also water cooled like this design from Stellantis. However, this system is not cast directly in the head like this. If something goes wrong and a recall is forced, BMW just has to replace the cases. If the same thing happens with the Stellantis design, that could be a huge problem.
It must also be said that this is bad for maintenance and aftermarket tuning. If a conventional car today has a fault in its turbo system, these parts can simply be replaced. With this configuration, this is no longer an option. An entire head must come off or some serious jerry-rigging must be done to correct a potential failure. The bottom line is that this setup focused heavily on increasing manufacturing efficiency, with other considerations far more compromised.
Indeed, the patent document explicitly states that this is all done to reduce “cost and complexity”. Today’s Turbo systems work very well and they are quite reliable, as the text notes; however, the metals needed to make the exhaust tips of the turbos—he specifically mentions nickel and chromium—are expensive, as are the multitude of components needed to assemble the systems. “Joints, fasteners, connecting tubes, conduits and other components” all translate into an expensive and complex piece of hardware. That’s not so bad for an enthusiast looking to add power later in a vehicle’s life, but it’s a big deal for an automaker producing millions of vehicles.
The bottom line is that Chrysler engineers, if you can still call them that, are wading here in an uncharted ocean of innovation. Turbo housings and combined exhaust manifolds have already been made, as have exhaust manifolds integrated into the heads. However, at least in terms of a mainstream automotive product, that’s not the case with inline turbos. Similarly, an exhaust side of the aluminum turbocharger, which this design hangs its hat on, was not widely developed.
If successful, Stellantis could save a lot of money and simplify its vehicles. If he’s wrong, it’s a potential warranty and recall nightmare. Either way, it’s some interesting engineering, and we’ll have to wait and see if it ends up on any Stellantis-family vehicles. Will Ram follow Chevy’s lead and put a big four-cylinder turbo engine in its full-size pickups? Will Dodge anger every Mopar enthusiast on the planet and make a four-cylinder Challenger? The transmissions of either of these cars could feature this type of turbo system.
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