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Tula presenting diesel Dynamic Skip Fire technology at Future Diesel Powertrain Summit in Shanghai

Tula Technology is presenting its diesel Dynamic Skip Fire (dDSF) technology (earlier post) at the 4th Future Diesel Powertrain Summit China 2020 on 24-25 September 2020 in Shanghai, China. In addition to providing an overview of dDSF technology, the presentation will address the Cummins-Tula 15L Heavy-Duty dDSF Project as well as the FEV-Tula 2.3L dDSF Simulation Project.

As demonstrated through testing, Tula’s dDSF technology reduces tailpipe NOx emissions by up to 66% while also reducing CO2 emissions by up to 4%. Importantly, dDSF is able to combine improved tailpipe emissions while simultaneously reducing fuel consumption, thus combining two critical objectives that have previously competed against each other.


Comparison of baseline and dDSF CO2 and NOx on HD FTP cycle and LLC. Source: Tula.

Like DSF for gasoline engines, dDSF uses individual cylinder deactivation control strategies to meet torque demand at optimal fuel and aftertreatment efficiency. Key solution components include:

  • DSF Valvetrain: Individual cylinder deactivation capability

  • Engine controller with dDSF: Tula’s proprietary SW for smooth, efficient operation and fuel economy gains

  • dDSF offers the opportunity to decreased after-treatment costs

  • Additional synergies can be gained by coupling dDSF with hybridization

dDSF improves fuel efficiency by firing all events at the most efficient ratio of air to fuel, allowing optimal combustion at all engine output levels.

Cylinder deactivation also reduces excess engine airflow, increasing exhaust temperatures. This allows for more efficient conversion of pollutants in the catalyst and reduced NOx, at no additional after treatment hardware cost.

dDSF technology enables manufacturers of commercial vehicles to meet the increasingly stringent emissions regulations in China.



There is little need for diesels in the future because their pollution and poor performance has no place. But, mostly they have no place because electric vehicles are vastly more powerful and economic, even in the heavy construction equipment spaces.
Many dreamers have succumbed to the diesel progerganda over the decades not knowing it was based on the fact that diesel was a surplus fuel of the refining process. That's why it was cheap and the truckers developed the market; however, when jet engines started using it, the market demand increased and the prices shot up to where they are today. A diesel engine has many shortcomings that now limit their longevity; it no long burns high sulfur fuel which helped lubricate the upper end, engine power is lost pumping high pressure fuel to direct injection, the high compression ratio beats up the head and valves and emission devices eat away much of the gain in economy, The present day diesel is not your father's diesel and are to be avoided.


On the other hand, a recent study by UC Davis calculates that the battery pack for a 500-mile EV semi-truck would require ~1400 kWh and weigh ~7 tons. Not only are 7 tons of batteries not remotely "eco friendly," they displace 26% of the revenue load compared to diesel trucks. That's more or less confirmed by https://www.youtube.com/watch?v=oJL9MasBFvM (second-half of video). That means that in some cases, 5 BEV semi-trucks would be required to move the same payload as 4 diesel semi-trucks. Will trucking companies go for that?

Even apart from the payload issue, the economics of BEV semi-trucks vis-à-vis diesel semi-trucks are questioned in the UC Davis study. Only under the most optimistic scenarios for BEV trucks will they match diesel trucks in cost-to-own, according to that study.

As for longevity, current diesel truck engines routinely last 1,000,000 miles without an engine overhaul. Will BEV truck batteries and traction motors last that long?

And of course, the whole point of this GCC article is that NOx emissions from the exhaust can be significantly reduced with this technology, while gaining efficiency concurrently. NMHC, CO, PM/PN emissions are already near-zero . The notion that BEVs produce no pollution is also a dream.

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