Premium Hydraulic Fluid Formulated to Meet Modern Equipment-Design Trends

Hydraulic fluid power is preferred over electromechanical drives in high-power mobile equipment due to its superior energy density, design flexibility and value. It is also a relatively mature technology and ripe for innovation. For the construction industry especially, machinery like excavators, loaders, graders, dozers, haul trucks, and drills rely on hydraulics to make the work safer, faster, and more efficient. In this type of application, hydraulic fluid is pumped to various hydraulic motors and cylinders throughout the machine and becomes pressured. The fluid is controlled by valves and distributed through hoses, tubes, or pipes.

Hydraulic oil ranks high among fluids with multi-function capability. Hydraulic oil does serve as an energy-transmission medium, heat-transfer medium, sealant, and lubricant as it powers buckets, blades, and breakers, for example, or propels hydrostatically driven machines, or actuates multi-disc clutches and brakes. To meet the requirements of these varied applications, hydraulic oil’s formulations are numerous. There is a wide variety of hydraulic fluids available in the market today, and not all created equally in terms of their performance or intended application.

Driven by a number of factors, today’s hydraulic equipment such as excavators, loaders, bulldozers, cranes, graders and more are rapidly evolving to meet new needs. Lower emissions targets around the world necessitate that hydraulic equipment operates more efficiently, while end-users are demanding hydraulic machines that deliver higher levels of performance over extended periods of time.

Modern machines are designed and manufactured to perform at ever higher levels, which puts more demands on hydraulic oils. They must perform under higher system pressures, with smaller oil reservoirs and tighter clearances on servos and directional valves. A premium hydraulic oil will improve the performance of machines relative to conventional fluids by achieving a fine balance of additive chemistry, base oil, and fluid cleanliness to insure the highest performance. Properties such as excellent fluidity at low temperatures, outstanding corrosion and oxidation protection, superior viscosity control, ability to keep components clean and free of varnish, and fluid cleanliness that meets OEM specifications are all critical requirements a premium hydraulic fluid takes into consideration.

Premium hydraulic fluid is a special hydraulic fluid formulated from highly-refined base stocks and an advanced additive system to deliver ultimate equipment performance with extended service intervals. Premium hydraulic oils have special properties that make them more expensive than regular ones. They may be designed for specific applications to deliver high-performance characteristics. Premium hydraulic oils may be formulated with additional additives to improve their performance and protection against corrosion, oxidation, foaming, or cavitation.

Trends impacting hydraulic-equipment development

Increasing power density and internal pressures: To compete with electric systems that are quickly capturing more of the market, hydraulic systems are increasingly lighter and more power-dense. Smaller pumps are expected to produce the same power, which in turn increases internal pressures. Hydraulic fluid manufacturers increasingly are turning to high-performance additives to improve their protective qualities.

Minimized power loss: Equipment designers are more focused on efficiency than ever before and have reduced the number of bends, joints and filter differentials to boost overall machine efficiency. As the rising costs of energy encourage more end-users to seek out even the smallest energy savings, OEMs are examining the role energy-efficient hydraulic fluids can play in further improving performance.

Finer filtration: It’s generally understood that hydraulic pumps are extremely sensitive to contamination, and the increased pressures as well as decreased clearances in valves and pumps have further accentuated the need for the fluid to be ultraclean. Finer filters are being employed to achieve the necessary cleanliness. As a result, hydraulic fluids must be resistant to clogging these filters and retain their key performance parameters post filtration.

Smaller oil coolers and reservoirs: Smaller oil coolers and reservoirs employed in equipment means that there is less opportunity for the fluid to cool between cycles. This will influence the effective life of the fluid — for example, a 10°C (18°F) rise in operating temperature could halve the oil drain interval (ODI). For this reason, hydraulic fluids must exhibit good thermal stability and antioxidant properties. With less lubricant available because of the smaller reservoirs, the remaining lubricant can come under enormous stress – which is why additive treat levels must increase to compensate for the additive being consumed more rapidly if today’s lubricant drain intervals are to be maintained.

Increasing electronic and digital control: Control systems employ an increasing array of electronics to match the hydraulic pressure and flow to precise torque requirements, which can maximize specific duty cycles. In fact, the construction-equipment OEMs provide electric-drive capability while still using a hydraulic solution in combination.

In addition, precise control of equipment is being provided by using digital valves that are 25 to 100 times faster than analogue valves. Modern hydraulic lubricants must have low air content and compressibility to prevent damage to these digital valves.

Implications for hydraulic fluids

As manufacturers develop the next generation of hydraulic fluids, they must support new hydraulic equipment in several key areas. While it can be measured in different ways, improved efficiency is increasingly a goal of OEMs and operators of hydraulic equipment. Using energy-efficient hydraulic fluids can provide a solution without having to completely re-engineer the machines, which can be cost-prohibitive.

For most end-users, extending the oil drain interval (ODI) is critical to operating their hydraulic equipment. After all, draining and replacing hydraulic fluid means extended downtime and lost productivity. Premium hydraulic fluids need to be changed less often and can therefore provide the necessary durability and performance for longer periods of time.

Stick/slip performance is another goal of most OEMs. They want to reduce noise in their machines, and premium hydraulic fluids can help. Correctly formulated hydraulic packages provide the adequate balance between friction modification and traditional anti-wear components, leading to less noise without compromising system protection.

Considering the conductivity of a hydraulic fluid also is critical. OEMs express more concerns about finer fibers in the oil filter, together with higher flow rates and non-conductive circuits. High static discharge can rip a hole in a hydraulic filter leaving the whole hydraulic system vulnerable to harmful particles. Modern hydraulic fluids must exhibit conductivity particularly during cold-starts and manufacturers need to be attentive to this requirement moving forward.