Swapping spark plugs for nanopulses could boost engine efficiency by 20%

More precise ignition events mean better fuel efficiency and fewer pollutants.

Here in 2019, only the most fringe reactionaries are able to claim with a straight face that climate change is not a thing. But after years of the media doing its “two sides” thing, recalcitrant policy makers dragging their heels, a continued lack of investment in public transport, and intense, well-funded opposition from vested interests like the oil industry, there has been a heavy cost on attempts to decarbonize. When it comes to the transportation sector, even with the best will in the world, it will be decades before we see the end of the internal combustion engine. So when a new technology comes along that offers a really meaningful improvement in fuel efficiency when fitted to existing engines, my interest gets piqued. Such is the case with a new ignition system from a company called Transient Plasma Systems.

The company has its roots in pulsed power technology developed for the Department of Defense at the University of Southern California, specifically nanosecond-duration pulses of power. Since 2009, it has been working on commercializing the technology for the civilian market in a number of applications, but obviously it’s the automotive one that interests me.

In a conventional four-stroke internal combustion gasoline engine, which works on the principle of suck-squeeze-bang-blow, the bang is created by a spark plug igniting the fuel-air mixture in the cylinder. That spark typically lasts several milliseconds, and although the control of that spark is now controlled electronically rather than mechanically, the principle is the same today as it was in 1910 when Cadillac added it to its engines.

TPS’s system does away with the conventional coil-on-plug approach. Instead, much shorter pulses of plasma—several nanoseconds—are used to ignite the fuel-air mix inside the cylinder. These have a much higher peak power than a conventional spark; thanks to their much shorter duration, however, the ignition is actually still rather low-energy (and therefore lower temperature).

Consequently, it’s possible to achieve better combustion at high compression ratios, more stable lean burning, and lower combustion temperatures within the cylinder. And that means a more efficient engine and one that produces less nitrogen oxide. TPS says that using its system, it can increase the thermal efficiency of an already very efficient internal combustion engine like the one Toyota uses in the current Prius (which is ~41 percent) up to 45 percent—similar to the turbulent jet ignition systems that have recently seen Formula 1 gasoline engines reach that level.

What makes this tech really cool—at least to me—is that TPS has designed the system to be drop-in for existing spark plugs, so OEMs don’t have to redesign their engines to use it. And on top of that, there’s no reason it can’t work in combination with other recent advanced engine technologies like Delphi’s dynamic skip fire (which allows highly accurate cylinder deactivation), Nissan’s variable-compression ratio engine, or even Mazda’s clever Spark Controlled Compression Ignition system.

Although it’s designed as a drop-in system, forget about fitting it to your own car—TPS’s going-to-market strategy is to work with an established tier-one supplier to leverage existing relationships with OEMs as well as existing manufacturing capacity. TPS told me it’s a little too early to get specific about the cost of its system versus conventional spark ignition but that the fuel economy gains it would deliver should please the OEM beancounters who weigh up things like expected fuel efficiency versus production cost.

 

 

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