Building a Better Mouse Trap: Extending the Life of the Internal Combustion Engine – Part 2

Benefits of Jetfire Power

In my prior post I introduced Jetfire Power technology as a form of Turbulent Jet Ignition (TJI) developed by Professor Harold Schock at Michigan State University, and I explained how it works in broad terms. Basically, it is a way of using a flamethrower (like the Army guy in the illustration above) to ignite the air/fuel mixture in an engine, even at highly dilute levels of over 40% EGR (exhaust gas recirculation). I have also compared it to lighting a campfire with a single match vs a flame thrower... This is accomplished with the mechanism depicted in the images below. Air and fuel are injected into a pre-chamber, which is then ignited by a spark plug, and the results are multiple torch flames radiating from the pre-chamber nozzle into the main chamber: 

What I did not cover earlier were the expected benefits of Jetfire Power ignition. Professor Schock and his team have tested the Jetfire Power system at EGR levels over 40% in experimental “optical” single-cylinder engine set-ups. “Optical” engines are specially designed to allow pictures of the combustion process but only can run for brief periods at a time. The top of the piston is a sapphire crystal!

The chart below has pictures from optical engines - as the expression goes, "a picture is worth a 1000 words"... The first row of pictures show the combustion process in a conventional homogeneous charge gas direct injection (HCGDI) engine from the initial spark to the eventual combustion. The following two rows of pictures show the main chamber combustion in a Jetfire Power engine. The red arrow shows a conventional spark plug initiating the “single match lighting a campfire” combustion process in the HCGDI engine (can you see the tiny dot in the middle of the first circle?). The green arrow shows Jetfire Power's “flamethrower” initiating the main chamber combustion. Finally, the yellow arrow shows Jetfire Power operating with 40% EGR.  The key takeaways here are that the Jetfire Power flame fronts are all in blue, have broad coverage, and show no yellow fuel-rich spots where soot and particulates are formed.

Jetfire Power’s compatibility with high dilution levels allows for lower pumping losses, improved thermal efficiency, knock resistance, higher compression ratios, and extended lambda 1 operation. These all combine to provide a cleaner and more efficient engine - the “better mouse trap” I mentioned in the title of this article.  

Based on testing and modeling, Jetfire Power's fuel efficiency benefits are estimated to be quite significant – approaching double digit percentage point improvements on an EPA cycle, which makes the $/gr CO2/mi also extremely attractive. These results are documented in a recent SAE paper (2020-01-1117 Published 14 Apr 2020 - Ultra-Lean and High EGR Operation of Dual Mode, Turbulent Jet Ignition (DM-TJI) Engine with Active Pre-chamber Scavenging).

Jetfire Power technology is applicable to all spark ignited engines – from pure gasoline or ethanol, and blends of the two, as well as gaseous fuels, such as CNG and LPG. It can even make diesel and jet fuel work with spark ignition! Speaking of diesel, Jetfire Power likely can be applied to a current diesel engine converted to gasoline, maintain basic performance and towing capabilities, and enable a three-way catalyst aftertreatment system. This could save $1000’s of dollars in total system cost given the deletion of the DPF (diesel particulate filter) and SCR (selective catalytic reduction) urea systems.  

Professor Schock has a single-cylinder “metal” Jetfire Power engine ready for testing to confirm the maximum EGR range, as well as the efficiency gains over a wide set of operating and technical conditions.  It has been ready to “run” for several months, but the labs have been closed at Michigan State due to the Covid-19. Plans and procedures to re-open the lab are complete and ready, so it might be open by the time you are reading this article.  

I will come back next with an update on the “metal engine”. In the meantime, please feel free to contact me directly with any questions at [email protected].