Patent previews engine with one turbo per cylinder

A one-time Ford engineer has filed a patent for an engine with turbochargers on each individual cylinder.

Jim Clarke was involved in the development of the Duratec V6 and ‘modular V8’ during his tenure with the Blue Oval. He’s teamed with ex-Navistar engine president Dick Fotsch on this project, which could be his most influential piece of design – should it make the jump from concept to reality, of course.

Rather than using a single turbocharger to boost the engine, Clarke suggests pairing a small turbine with each cylinder. His patent filing, reported in Car and Driver, refers to the design as “synergistic induction and turbocharging”.

The setup would require individual throttle bodies for each cylinder – one for each intake port – sitting next to the cylinder head. According to the patent, the setup allows cylinders to fill faster (the patent filing uses the term “hyper filling”), building torque and high-energy exhaust gas more quickly in the process.

Taking advantage of that high-energy exhaust gas are small turbochargers mounted as close as possible to the exhaust valves.

According to Clarke, the closer you put the turbine to the exhaust valve, the more energy on hand to accelerate it. The turbochargers in his design can be significantly smaller than those found on single-turbo engines – 20 per cent smaller, in fact, with 50 per cent less airflow required.

Above: Audi has developed an ‘electric turbo’ for the SQ7

Smaller turbochargers have less rotational inertia, which makes them easier to spin and cuts down on turbo lag. In fact, the patent filing says the system could cut ‘perceptible lag’ completely.

All of these are good things, but there are a few hitches that could stop the concept becoming a reality.

For one, it would be considerably more complicated than current turbo setups. A three-cylinder engine using this design would require three turbochargers and six throttle bodies, rather than one of each in a conventional setup.

The other thing worth considering is, in their attempts to make turbo engines feel naturally aspirated, current manufacturers are working on their own technology. The patented engine would need to be significantly more effective than those setups to be considered for production.

Above: The AMG GT has its turbochargers inside the ‘vee’ 

Mercedes-AMG, among others, nestles the turbochargers inside the ‘vee’ of the engine to minimise the distance charged air and exhaust energy need to travel, delivering sharper throttle response in the process.

Elsewhere in Germany, the Audi SQ7 uses an ‘electric turbine’ to help deliver 900Nm of torque from just 1,000rpm. A compressor wheel can spin at 70,000rpm without any exhaust gases to drive it, which means boost is available in less than 250 milliseconds from low revs.

Clarke’s idea is just that at the moment – it exists only on paper, with no working prototype. But it shapes as another interesting way to mix punchy performance with regulation-pleasing emissions, should it ever get off the ground.

MORE: Technology news