Keeping commercial vehicles running efficiently and reliably is no easy task. They need to perform consistently, require less maintenance, and stay cost-effective over time. That’s where Cummins’ ‘lashless valvetrain technology’ comes in—a smart upgrade aimed at making engines tougher and easier to maintain.
At the centre of this system is something called a Hydraulic Lash Adjuster (HLA). In simple terms, it automatically takes care of the space between engine components that normally needs to be adjusted by hand during production and servicing. This means better engine performance, less wear and tear, and fewer service stops.
Cummins Valvetrain Technology (CVT) has been pushing this idea forward. After first launching HLAs in an off-highway engine in 2021, it has now developed a more advanced version for its B6.7 Octane engine. This new system combines HLAs with engine braking capability, improving both power delivery and control—all while keeping downtime to a minimum.
How Cummins Solved A Tough Engineering Puzzle
One of the cleverest parts of Cummins’ lashless valvetrain is the way it uses HLAs to keep things running smoothly. HLAs automatically adjust the tiny gaps in the engine’s valve system—gaps that usually need to be set by hand. This saves time in both manufacturing and maintenance, and it’s a big plus for trucks, off-road machines, and spark-ignited engines that work in tough conditions.
But making HLAs work well with engine braking systems hasn’t been easy. When a truck uses engine braking, the brake system can create too much gap—or “lash”—which might cause the HLAs to stretch too far. That can damage the engine valves, and in worst cases, lead to serious internal contact between the valve and piston.
The engine maker has cracked this problem with a lashless design that applies a counterforce during braking. This keeps the HLAs in check, so the engine runs safely and smoothly even under heavy braking. The result? A system that boosts engine performance, cuts down maintenance, and makes engines more dependable across demanding applications.
Smarter Valvetrains, Smoother Engines
Cummins’ lashless valvetrain technology does more than just cut maintenance—it brings together performance, reliability, and simplicity in one smart package. By letting HLAs work hand-in-hand with Jacobs Engine Brakes, the system ensures powerful braking and precise valve control without the need for manual adjustments.
To make this work across different engines and brake types, the company uses innovative components like the Fulcrum Bridge and Spring Bridge. These make the system flexible enough for a wide range of engine layouts—including those powered by petrol, natural gas, or hydrogen, where valve wear tends to be higher.
By removing manual lash adjustments, the system boosts uptime, reduces the chance of errors, and simplifies both production and service. HLAs also make it easier for engineers to design camshafts that improve fuel efficiency, emissions, and engine smoothness.
For off-highway machines that work in dusty, remote areas, avoiding valve lash checks means less downtime and lower costs. And in the factory, skipping lash settings speeds up assembly and improves productivity.
Additional bonus is that HLAs help make engines quieter and smoother by optimising the operation, eventually reducing noise, vibration, and harshness for operators working long hours.
Moreover, Cummins’ lashless technology fits right into existing engine platforms, making it a smart, cost-effective upgrade without adding complexity.
HLAs Find Their Place In Off-Highway Engines
For years, HLAs were rarely used in off-highway engines because they couldn’t handle the demands of engine braking. Braking created gaps in the valvetrain that caused HLAs to overextend—leading to poor performance and the risk of engine damage.
The engine manufacturer has solved that problem. With its lashless valvetrain systems, HLAs now stay stable even during braking. This breakthrough makes HLAs viable for commercial and off-highway vehicles, helping manufacturers build cleaner, more efficient engines without adding complexity.
For engine makers, this means better performance and easier emissions compliance. For end users, it means fewer maintenance issues, less downtime, and a quieter, smoother ride—all of which help reduce the total cost of ownership.
CVT has led this shift; its Fulcrum Bridge and Spring Bridge systems make HLAs compatible with engine brakes across various engine platforms. These advances laid the foundation for the B6.7 Octane engine, which features a fully integrated lashless valvetrain and HLA setup. Tailored for gasoline engines, the Octane marks a new chapter in reliable, low-maintenance power for tough working environments.
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