Designed to deliver faster engine braking and more fuel-efficient brake-assisted gear shifting.
The patented wedge capsule hardware, available on the crosshead, rocker arm and pushrod valvetrain components, is behind the company's decision to develop its first-ever mechanical engine braking system. It is an alternative to the high-pressure hydraulic chamber used in conventional compression release engine braking systems.
Removing the hydraulic chamber from the system improves brake response time by up to 60% without any loss in capability. It reduces an average 300-350 millisecond duration for slab brakes, and around 250 milliseconds for rocker brakes, to less than 100 milliseconds in the Cummins X15 engine.
For OEMs using automated manual transmissions (AMTs) with engine brake-assisted gear shifting, wedge capsule technology extends the performance envelope. The 100-millisecond response of the wedge capsule shortens the brake activation window, reducing vehicle speed droop and the fuel penalty associated with re-acceleration after gear engagement.
The wedge technology uses a two-step actuation mechanism that protects the system when a partial engagement event occurs, a known failure mode in other mechanical engine brake designs that use single-actuation pin lock systems. When partial engagement occurs, the wedge geometry limits load transfer to approximately 30% of full actuation force, preventing component damage. The system also requires no crank angle-based activation control, simplifying integration for OEM engine management calibration teams.
Another benefit is the elimination of hydraulic compliance: in hydraulic systems, oil compressibility under high valve loads results in lift loss, which must be compensated through additional cam lift. A mechanical load path removes this variable entirely.
On the X15 engine, wedge capsule technology is deployed in the compression release engine braking system, where it will deliver the highest total braking power in its class. On the X10 engine, the technology is integrated into the Jacobs® High Power Density® (HPD®) engine braking system, where two capsules are used, one for cylinder deactivation (CDA), and the other for braking activation. The X10 engine will deliver the highest specific braking power in its class. Source