The new partnership, say the companies, will use Tula’s Dynamic Skip Fire controls technology to support Jacobs’ developments in diesel deactivation hardware.
Jacobs introduced its CDA (pictured) system for medium- and heavy-duty commercial vehicle engines in 2018. CDA mechanisms are used in the valvetrain to disable the opening of the intake and exhaust valves.
The hydraulically-activated mechanism is integrated in a collapsing valve bridge system for overhead camshaft engines, or with a collapsing pushrod system for cam-in-block engines. When combined with disabled injection in selected cylinders, multiple cylinders can be deactivated as needed. At low engine loads with three of six cylinders deactivated, says Jacobs, fuel consumption can be improved by up to 20%.
Tula’s Dynamic Skip Fire system makes firing decisions based on how much torque is requested, choosing which cylinders will be active or deactivated to meet performance demand. When more torque is required, the firing density increases; when there is less demand for torque, firing density decreases.
Robb Janak, director new technology, Jacobs Vehicle Systems, says: “Vehicle manufacturers are looking for new and improved technologies to comply with stricter legal limits on CO2 and NOx emissions... Cylinder deactivation is a great solution, technically proven and cost effective.”