Tula Turns Focus to BEVs

NOVI, MI – This time, Tula Technology believes it’s gotten the timing right.

The California-based startup, known for its Dynamic Skip Fire (DSF) multi-cylinder-deactivation software in production since 2018 on most V-8-powered General Motors fullsize pickups and SUVs, has turned its attention to the battery-electric-vehicle market with a new product, Dynamic Motor Drive (DMD), aimed at optimizing electric-motor and inverter performance.

Tula’s original DSF technology is an amazing piece of software to witness in action. It continuously makes dynamic firing decisions on an individual cylinder basis to deliver required engine torque for all vehicle speeds and loads, while avoiding vibration issues. It can cut fuel consumption up to 15%.

The problem with DSF was it bowed just as the auto industry was turning away from new investment in internal-combustion engines and focusing its product-development dollars on electrification. To utilize DSF, automakers needed to redesign their ICE valvetrains, and that was an investment few were willing to make as the shift to BEVs was unfolding.

“We had a number of programs in the works that all got shelved,” Tula CEO R. Scott Bailey says here at a backgrounder and demonstration of the company’s newer DMD technology on a retrofitted Chevrolet Bolt and a Tesla Model 3.

Tula began its pivot toward BEVs in 2018, and since then it has secured 24 U.S. and 10 international patents for its DMD software and has more than 100 additional patents pending worldwide.

“It’s not rocket science, but it is pretty clever,” Bailey says of the technology.

Like its Skip Fire ICE counterpart, DMD is designed to ensure the BEV powertrain is running in its most efficient state under all modes of operation. As a driver accelerates, decelerates or maintains a constant speed in a BEV, the motor isn’t always operating at its peak torque efficiency. If what is being demanded is below the optimum level, the DMD software quickly pulses the motor to bring torque into its sweet spot on average.

Pulse frequency can range from 25 to 40 Hz – or 25 to 40 pulses per second. The pulsing occurs during acceleration as well as deceleration and the battery-regeneration phase.

“(The operation) is imperceptible to the driver and passengers onboard the vehicle,” notes John Fuerst, senior vice president-DMD and Engineering.

There’s no additional wear on the motor, inverter, battery, power electronics or other key components as a result, according to Tula’s modeling.

“We’re pulsing well below the endurance limit,” Fuerst says. “You can do that forever and it is going to be fine through an infinite number of cycles. The main challenge is just managing the NVH.”

Efficiency gains – coming mostly from better operation of the motor core and reduced inverter switching – can be modest overall, equating to about 0.4% to 3.0% in terms of range on the U.S. driving cycle. The Bolt test vehicle here that features interior permanent-magnet motors (IPM) gains about 0.6% and the more optimized setup used on the modified Telsa tester, in which Tula swapped out the car’s IPM motor for its own design using a magnet-less wound rotor, boosts range around 3.0%. The figures equate an additional 2 to 9 miles (3.2-14 km) between charges on a BEV with 300 miles (483 km) of range, assuming the battery capacity is unchanged.

But even those small increases could allow automakers to reduce battery and other BEV costs. Tula estimates every 1% gain in efficiency equates to an $80 savings, meaning at the low end, automakers would save automakers about $25 after accounting for the cost of the software. That figure would rise to more than $150 per unit in a vehicle deploying DMD on a system consisting of an externally excited synchronous motor (EESM) and conventional (non-silicon-carbide) inverter technology.

Though IPM motors account for about 90% of BEV applications, automakers already are creeping toward EESM applications as they look to reduce reliance on costly and environmentally concerning rare-earth materials needed for IPM motors.

“Most of the industry is doing serious work on EESM,” Bailey says, meaning the greater savings possible with DMD could be there for the taking.

There were no glaring NVH or performance issues during our test drive, and it was hard to tell anything different about the modified Bolt and Tesla – exactly what Tula was eager to demonstrate. A screen showed readouts of the software at work, with the motors in the two applications pulsing rapidly in and out at around 25 Hz to maintain torque equilibrium during a short drive on surface roads.

Tula is asking automakers to pay for the software with a third of the realized cost savings from the improved efficiency, meaning about $10 per unit at the low end and $80 per vehicle at the high end.

“That’s our (pricing) position going in. And we’re not seeing too much pushback on that,” Bailey says.

Competition for those dollars can come from a number of areas, because there are many incremental improvements that can be made to boost BEV efficiency and extend range, from better aerodynamics to low-rolling-resistance tires. But as they look for every bit of incremental gain, it’s likely automakers will apply more than one solution to extending BEV range and/or lowering cost, opening the door for Tula.

“While (it) doesn’t sound like much, I can guarantee you every OEM around the world is very interested in a 0.1-point gain in efficiency,” Bailey says. “Why? Because they know they need 10 of those – there’s no one silver bullet out there.

“We are not claiming we solve every problem under the sun,” he adds. “But we like our play, because it’s software. It doesn’t require new parts or a change in the supply chain.”

DMD eats up only a fraction of a BEV’s computing capacity, Tula says, and once integration issues are resolved, the software could be rolled out to vehicles on the road through an over-the-air update.

As for Dynamic Skip Fire, that business still has a little life, finding application in some commercial diesel engines (Cummins) because of its ability to reduce emissions. Bailey says the product could get a boost after 2027, if more stringent emissions regulations are enacted in Europe and other regions. But despite reviving interest in developing new ICEs at some automakers, Tula doesn’t expect new applications for its DSF technology on gasoline engines, and DMD is seen as the driving force in the company’s future overall.

“For certain use cases, there’s no doubt in my mind electric propulsion is a better bet,” Bailey says. “When we get battery technology and charging infrastructure where it needs to be, people will move (to BEVs). It makes too much sense.”

Bailey says Tula easily should capture a 20% share of the global BEV market with DMD in 2030-2035.

Currently, the strongest interest in the new software  is coming from Europe and China. The U.S. is trailing as a result of the near-term softening of BEV volume expectations and policy uncertainty surrounding November’s presidential election, but Fuerst says “a number of guys are telling us this looks interesting.”

The first DMD production application is targeted by an unnamed automaker for later this year in China, though Tula executives caution that timing may be ambitious.

The company’s biggest roadblock to success is manpower and reach, Bailey says. That has Tula on the hunt for a more strategic investor that could help open the door to customers internationally and put some manpower behind more development projects. A Tier 1 motor/inverter supplier would make a great fit, Bailey acknowledges.

Currently, six companies have 10%-15% stakes in Tula: Sequoia Capital, Khosla Ventures, Sigma Partners, GM, BorgWarner and Franklin Tempelton

“What we really need for a partnership is the strategic reach a lot of the big guys have,” he says. “We have a lot of things we intend to do, but the question is, do we do it on our own or through a strategic partnership? And frankly, you win with speed, and I’m not sure we can run fast enough on our own.”