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Does twin-turbo V8 patent show the future?

by David Zatz on

There have been rumors that the Hemi engine is due for an upgrade, which is allegedly to push the 5.7 above 400 horsepower.  Another rumor claims that the Hemi is leaving sedans and coupes in 2019, though likely remaining in trucks and some SUVs.

A patent application filed in 2013 shows one idea for a Hemi upgrade; it would not apply to the rumored Pentastar-based V8 (unless a brand new block was created with Pentastar technologies, since it specifically mentions a 90 degree V-engine and the V6 is a 60 degree design).


Patent drawing colorized by Allpar.

Ken Hardman’s patent shows a new type of exhaust gas recirculation (EGR) system using dedicated EGR cylinders, one or more per bank. The idea would be to keep exhaust in certain designated cylinders, rather than to distribute it throughout the entire engine.  (EGR is used to reduce harmful nitrogen oxide emissions, a difficult problem for the Hemi design). The dedicated EGR cylinders would exhaust gases directly into their own intakes rather than using EGR valves.

The setup was created to prevent a problem that can happen in engines where the same cylinder in different banks fire one after the other (e.g. the rearmost cylinder of bank 1 firing just before the rearmost cylinder of bank 2). This can bring exhaust blowback interference, so that one cylinder has to pump harder, and one ends up with residual exhaust, causing minor performance issues. V6 engines usually do not have the same issue, due to a different firing order.

The example uses a twin turbocharged engine, though other engine configurations are also covered. See the patent. Thanks, Steven St. Laurent.


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