Unlike current cylinder deactivation strategies that shut off a fixed number of cylinders, DSF makes dynamic firing decisions every 90 degrees of crank angle on a V8 (180 degrees on a 4 cylinder engine) based on how much torque is requested.
The result: the engine dynamically fires the optimal number of cylinders to maximize fuel economy while maintaining a smooth ride with commercial levels of noise and vibration.
Creating an Engine to Order
DSF delivers a highly responsive approach to variable engine displacement. When more torque is required, the firing density (the ratio of cylinders actually fired to the maximum possible) increases. With less demand for torque, the firing density decreases. The DSF algorithm effectively creates an engine with optimal displacement for the torque required.
Non-DSF engines waste energy by closing the throttle to limit air intake, increasing pumping losses. DSF engines limit cylinder firings instead, reducing pumping losses and increasing efficiency.
Fuel Efficiency Without Compromise:
Passenger Comfort Guaranteed
DSF algorithms are developed to maintain a smooth ride for any amount of requested torque. Tula’s proprietary firing decision and control algorithms avoid generating noise and vibration (N&V) to give drivers the expected levels of refinement under all driving conditions.
How DSF improves fuel efficiency
Reduction in Pumping Losses
DSF enables engines to operate with high manifold pressure, ensuring operation in a sweet spot of thermal efficiency for each cylinder at each engine speed.
Improvements in Combustion
Higher cylinder loads and greater stability in firing combustion improve burn efficiency on DSF engines.
Deceleration Cylinder Cut Off (DCCO)
When the driver takes his foot off the accelerator, DSF deactivates the cylinders, ensuring that fuel consumption is zero while maintaining catalyst balance and temperature. This improves both fuel economy and emissions.
Fast Torque Control
Because DSF can operate without spark retard, the fuel is always burned at peak efficiency while providing required responsiveness.
Forward-thinking car makers constantly seek greater fuel economy
Generally, OEMs want to see new fuel economy technologies with a cost of less than $100 for each 1% improvement in fuel economy.
Value Proposition of DSF
Tula and DSF offer a cost-to-benefit ratio half of other new technologies.
Coupled with conventional and advanced technologies, Tula’s Dynamic Skip Fire (DSF) provides a clear path forward in optimizing the fuel consumption of the automotive fleet.
DSF leverages other advanced engine technologies synergistically to provide an even better cost-benefit ratio. There’s a DSF solution to complement each of the major new automotive trends. See how any DSF technology yields even greater fuel efficiency at a lower cost per % improvement.
Hybrid Electrification (eDSF)
eDSF couples DSF with mild vehicle electrification to enable greater fuel economy at lower cost. Electrification allows energy to be recovered during braking. Using this energy to drive the engine lets DSF reduce displacement and improve fuel economy. eDSF also improves energy recovery by using DCCO during deceleration.
Advanced Combustion (mDSF)
DSF is synergistic with advanced combustion strategies such as Miller cycle engines. Including DSF improves efficiency and avoids performance penalties by allowing these combustion strategies to be mixed with deactivation, on a cylinder by cylinder basis. DSF works synergistically to enhance fuel economy and ensure a smooth ride.
Diesel DSF applies Tula’s advanced engine control strategies to diesel engines with individual cylinder deactivation. In addition to improving fuel economy, dDSF improves catalyst efficiency by maintaining appropriate exhaust temperatures. This combines reduced fuel consumption and improved NOx tailpipe emissions with no additional after treatment costs.
aDSF improves fuel efficiency because the vehicle’s torque request can be modified with fuel economy in mind. Using connectivity to other vehicles and the cloud infrastructure, autonomous DSF vehicles will be able to anticipate acceleration and braking algorithmically, proactively managing the torque request to improve fuel consumption.