As government regulators around the world embrace ever-stricter emissions standards to curb greenhouse gas emissions and stem the tide of global climate change, the future of the internal-combustion engine looks fuzzy. To survive, ICEs will have to get a whole lot more efficient at doing what they’ve always done: converting an explosive mix of oxygen and liquid fuel into rotational motion.
Former Ford engineer Jim Clarke has helped come up with one novel potential solution to the problem, which involves utilizing a single, small turbocharger for each and every cylinder in an engine. A four-cylinder engine would have three turbos; a V8 would have eight; and so on and so forth. Clarke’s design puts each of these turbos as close as physically possible to the exhaust valves. Beyond that, the concept calls for twice as many throttle plates as there are cylinders – one throttle for each intake valve – again positioned with minimal distance from the valve.
“The closer you put a turbocharger to the exhaust valve, the more energy reaches the turbine to accelerate it,” Clarke told Car and Driver. Using individual turbos per cylinder would maximize each turbo’s ability to use exhaust energy to cram in more air. That should translate to greater efficiency.
Meanwhile, utilizing two throttles per cylinder, one to supply each intake valve, would allow the ECU to keep one shut at low RPM, maximizing intake-flow velocity. Each throttle’s proximity to the valves would also cut down on the total manifold volume that has to fill in order to supply each cylinder. Together, both innovations would allow the cylinder to fill more quickly, unlocking greater low-RPM torque and generating more exhaust to get those turbos spinning.
And of course, it stands to reason that each individual turbocharger would be significantly smaller than those in use on a typical modern ICE. With less rotational inertia comes quicker spool-up, reducing turbo lag.
The biggest concern with all of this is, of course, the cost. Between the extra turbochargers, the complex cooling and oiling systems required to support them, and the multiplicity of electronically-controlled throttles, one can imagine that such an engine might cost quite a lot to build, and require a Ph.D to diagnose and service when something goes wrong.
But we’d bet that Clarke, who beside working for Ford has served as Engineering VP at Navistar and led special projects at Kohler, has considered all of this. His technical partner, Dick Fotsch, formerly served as President of the engine departments at the same firms. Their “synergistic induction and turbocharging” engine is purely theoretical at this point, with no prototype yet built, but we have every reason to believe they know a thing or two about optimizing the ICE.
(Source: Car and Driver)