Powertrain Systems

Delphi Heavy Duty Roller Hydraulic Valve Lifters (HD RHVLs) are valve train components that convert the rotation of the cam shaft into linear motion. The roller provides minimal friction at the cam/lifter interface. Delphi HD RHVLs automatically eliminate clearance between valve train components to provide an adjustment and a maintenance-free system.

The key to the automatically adjusting system is a high pressure chamber and the control of engine oil out of, and into, the chamber. A plunger that resides in the lifter body has a precise clearance to the body, forming an annulus. When the plunger is loaded during valve lift, oil is expelled through the annulus. During valve lift, the plunger expels oil allowing the plunger to displace a small distance within the body. When the engine valve closes and the load is removed, the plunger spring and oil pressure keep the valve train components in contact. The plunger moves within the body to recover the distance that the plunger traveled during loading, plus or minus any changes that may have occurred. The check valve opens and refills the chamber. This process is repeated for every valve event providing continuous automatic adjustment.

Delphi's Heavy Duty Roller Hydraulic Valve Lifters also feature a metered oil supply for lubrication of the engine overhead through the push rod. The metering valve is designed to minimize sensitivity to contamination.

Diesel engine oils can contain significant amounts of soot created by the combustion process. Delphi HD RHVLs have optimized material and heat treatment specifications, and surface texture specifications to minimize the abrasive wear that can occur with the presence of soot.  

Benefits

• Anti-varnish design minimizes sensitivity to accumulation of dirt, gum and varnish
• Chrome alloy ball check valve provides more precise valve opening and closing events
• Hardened steel body and plunger minimize wear for life-of-engine service and minimize sensitivity to diesel engine soot
• Low-friction roller bearing with optimized surface textures helps maximize fuel economy and minimizes wear from diesel engine soot
• Roller surface is optimized to minimize the cost of cam lobe processing without loss of performance
• Oil metering provides lubrication to push rod interfaces and other valve train components
• Optimized dynamic performance design enables better control of the valve event at all engine speeds

Typical Applications

Delphi Heavy Duty Roller Hydraulic Valve Lifters are designed for all cam-in-block internal combustion engines. They can be used in diesel, gasoline or alternative fuel engines. They feature a larger outer diameter to fit larger lifter bores that are common in diesel engines.

Performance Specifications

This diagram shows overall measurements of the Delphi Heavy Duty Roller Hydraulic Valve Lifter. (Note: All dimensions are in millimeters.)

Performance Advantages

Delphi Heavy Duty Roller Hydraulic Valve Lifters feature a low-friction, high alloy roller bearing that helps improve fuel economy and reduces component wear. Delphi HD RHVLs are manufactured according to consistent processes and undergo extensive testing to deliver robust, world-class quality and proven reliability.

Delphi was the first to produce Roller Hydraulic Valve Lifters for the automotive industry. They have been in production since 1981 for diesel engines and since 1985 for gasoline engines. Today, more efficient, performance-oriented Delphi valve train systems are helping vehicle manufacturers meet more stringent emissions requirements and more ambitious performance objectives.

The Delphi Advantage

Delphi has more than 75 years' experience in valve train systems and our high-quality conventional valve train products have earned industry-wide respect. Delphi's deep understanding of the combustion process and our vast research and development capabilities have also enabled continuing innovation. Delphi is an industry leader in engine management systems, so whether a customer chooses a complete system or an individual component, Delphi's systems expertise is built into every product. Delphi can help manufacturers reach higher levels of performance while achieving regulatory compliance.