Commercial vehicles must ensure solid performance, minimize maintenance requirements, and reduce operating costs. Cummins helps customers achieve this goal through its lashless valvetrain technology which is designed to improve reliability, durability, and reduce maintenance requirements. The core of this technology is the Hydraulic Lash Adjuster (HLA), which eliminates the need for manual setting and adjustment of valve clearances. By maintaining optimized operation of the valves under various working conditions, HLA simultaneously improves engine performance and durability.
Cummins Valve Train Technology (CVT) is leading the development and integration of gapless valve drive systems, perfectly combining the advantages of HLA with engine braking. Based on the HLA system first introduced in off highway applications in 2021, CVT has developed a new generation gapless valve drive system for Cummins B6.7 octane engines, achieving compatibility design between full HLA and engine braking.
What is Hydraulic Clearance Adjuster (HLA)
The hydraulic clearance adjuster (HLA) technology automatically maintains the optimal valve clearance by compensating for changes in the valve drive mechanism. HLA does not require manual gap adjustment during production or maintenance, which is a significant advantage particularly suitable for off-road equipment, spark ignition engines, and commercial vehicle applications where reliability and maintenance convenience are crucial.
However, traditionally, there have always been technical challenges in combining HLA with engine braking systems. During the braking process, the additional clearance generated by the braking mechanism may lead to excessive stretching of HLA, posing a risk of valve erosion, and in severe cases, even causing contact between the valve and the piston.
Cummins has solved this problem with a gapless valve drive solution: applying reactive loads to HLA during braking to prevent excessive stretching and ensure safe and efficient engine operation.
Advantages of Hydraulic Clearance Adjuster (HLA)
Cummins seamless technology brings comprehensive advantages to off-highway and spark ignition engine applications, achieving higher performance, lower cost, and stronger reliability.
Implement HLA and engine braking cooperation: Cummins seamless valve drive system enables HLA to work with Jacobs ® The seamless combination of engine braking creates a solution that combines high performance and simplicity. Technologies such as pivot bridges and spring bridges ensure compatibility with various engine braking types and valve drive layouts.
Eliminating manual valve clearance adjustment: For gasoline, natural gas, or hydrogen engines, eliminating clearance adjustment is particularly important - these applications traditionally have higher valve seat wear rates. Cancelling gap adjustment can improve equipment availability, simplify maintenance processes, and reduce the risk of human error.
Optimizing cam design and engine efficiency: With HLA technology, engineers can fine tune the camshaft profile to achieve better performance, smoother valve seating, and higher fuel efficiency. The hydraulic cam design provides greater flexibility for valve timing control, helping to reduce emissions and fuel consumption.
Improving equipment availability and reducing maintenance: The gapless valve drive system eliminates gap checks and adjustments during maintenance, reducing downtime and maintenance costs, which is crucial for improving total cost of ownership (TCO). This is particularly valuable for off highway equipment operating in remote or harsh environments where engine maintenance is difficult.
Accelerating engine assembly: The valve clearance setting on the assembly line is time-consuming and often becomes a production bottleneck. Using HLA and Jacobs ® After the seamless solution, this step was completely eliminated, significantly reducing manufacturing time and costs.
Reduce noise, vibration, and impact: HLA improves valve seating accuracy, effectively reducing engine operating noise and vibration. It means a smoother and quieter driving experience for highway/off highway machinery operators, which is crucial for long-term operations.
Provide a simple and economical solution: Cummins seamless system achieves all advantages without increasing engine complexity. Jacobs seamless solutions such as pivot bridges and spring bridges can be integrated with existing engine platforms, providing a practical and economical upgrade path.
Why are hydraulic clearance adjusters becoming increasingly popular in non-highway fields?
Previously, HLA was unable to be compatible with commercial vehicle engine braking systems. The main event gap generated during the braking process can lead to excessive stretching of HLA, making it difficult to ensure reliable performance.
Cummins has changed this situation by innovating the gapless valve drive system, ensuring the stability of the valve mechanism during braking. This breakthrough provides engine manufacturers with powerful tools to improve performance, reduce emissions, while maintaining system simplicity, safety, and braking compatibility. This technology also helps to meet stricter emission regulations without compromising engine reliability or increasing maintenance burden.
The benefits for end users are evident: lower maintenance costs, less noise and vibration impact, and higher device availability time, all of which significantly reduce the total cost of ownership.
Who will provide a solution for hydraulic clearance adjusters?
Cummins Valve Drive Technology (CVT) has been leading the development of HLA compatible technology for many years. In response to the challenge of integrating HLA with engine braking, CVT has developed two mature solutions, namely pivot bridge and spring bridge, which have been applied to multiple platforms.
These innovations lay the foundation for the upcoming Octane system - an advanced gapless valve drive system that will achieve full HLA and engine brake compatibility. The B6.7 octane rating engine designed specifically for gasoline applications marks a crucial step forward for Cummins in optimizing engine efficiency, durability, and performance.