Transforming Propulsion with Tula’s Digital-Control Magic

June 1, 2018

Not just for ICEs: Tula Technology CEO Scott Bailey.

Behind GM’s recent introduction of its new Dynamic Fuel Management system on its small-block V8s for 2019 pickups (see article here) is the remarkable back-story of Tula Technology. Company founder Dr. Adya Tripathi brought the innovative concept of digital signal processing to engine control over a decade ago, attracting the attention of GM (which invested in the tiny start-up). GM Propulsion saw significant potential for adopting the DSP-based system — which Tula calls Dynamic Skip Fire — to provide sophisticated cylinder deactivation in its ever-evolving OHV V8. Tula’s next collaboration, with Delphi, focuses on developing the system for 4-cylinder engines, examples of which are under development in Europe and Asia.

Tula Technology has much more coming in advanced-propulsion technology including hybrid and EV developments, noted company President and CEO Scott Bailey. A 40-year powertrain engineering veteran, Bailey spoke recently with AE Editor-in-Chief Lindsay Brooke.

If someone said six years ago that they were considering a new ICE technology coming out of Silicon Valley, no one would’ve believed it.

People in the Valley would’ve laughed. Now, it makes perfect sense. I have to give GM big props for being willing to investigate the Tula technology and invest in it.

Some readers may be confused over the separate GM and Delphi implementations of Tula’s technology, as well as your work with other OEMs — would you clarify?

GM invested a lot of manpower to implement it, as DFM, on the 2019 truck V8s. It’s the first market validation for our technology and confirms its value proposition. It’s huge for Tula. Delphi did not play a role in the V8 system. For them it’s more of a 4-cylinder story — to prove the viability and value proposition of DSF on 4-cylinder engines. Delphi is responsible for valvetrain design and overall EMS integration. We’re focused on our core DSF firing block, we do the complete OBD package and take the lead in calibration. It’s been working very well.

We’re a couple years away from having the first 4-cylinder production program.

In general, are powertrain trends across the globe helping Tula?

Yes. Downsizing generally is slowing, due to RDE [Real Driving Emissions] concerns. Further downsizing is not delivering the fuel consumption reduction that was expected. On a 4-cylinder, downsizing from 1.6-L to 1.5-L is about as ‘deep’ as OEMs want to go realistically. At the same time, cylinder deactivation is becoming more prevalent, particularly in Europe. Many companies are standardizing around 2.0 L which is a perfect target for our system. Let us take care of the ‘downsizing’ via DSF software — only fire the percentage of combustion opportunities needed at a given load. That’s really the source of the savings.

What’s in Tula’s development pipeline?

Some extensions of the DSF technology. With Delphi we’re working on electrified DSF, to be paired with 48-V mild hybrid systems. By itself 48-V is good for about a 15 percent fuel consumption reduction. Combined with DSF we’re seeing reduction numbers on the dyno that are greater than the sum of the two separate systems.

Adding a bit of electric-motor torque opens up DSF’s ‘fly zone.’ We’ve developed P-Zero and P1 hybrid configurations that lets us do high-bandwidth control of the electric motor. We can both absorb torque and put torque back on the crankshaft within a given engine cycle, and do it very quickly, ‘smoothing’ the overall torque profile on the crankshaft. And that allows us to run certain firing densities that we would not be able to run otherwise. We use a capacitor to very briefly store energy and put that torque back on the crank quickly. All we need is a minor change in the power electronics and a capacitor. We can then pick up a couple extra points of fuel efficiency simply because we can now run [deactivate] in certain load places where we couldn’t run before.

Another development is DCCO — Decel Cylinder Cut-Off. It allows us to deactivate all cylinders for very low pumping load in deceleration mode. This greatly extends braking regeneration for battery charging.

And we’re also working to increase efficiency of pure electric propulsion. We’ve filed our first patents. We’re looking at evolving Tula into a propulsion-efficiency company, not just for ICEs.