While many types of hydraulic pumps achieve efficiency similar to Artemis's Digital Displacement® (DD) technology at their full flow rates, none can match DD's efficiency at partial displacements. In fact, DD machines lose so little energy efficiency at partial flow rates that they are close to uniformly efficient over the whole displacement range.

This outstanding energy efficiency is largely because, while not active, Digital Displacement® cylinders are completely isolated from the high pressure supply (see the Technology pages). There are no high pressure sliding interfaces to sap energy like there are in conventional hydraulic pumps.

System Efficiency

Digital Displacement® is not only more efficient in direct comparison to other technologies - dramatic efficiency gains are possible at the system level too. In conventional systems with just one or a few pump outputs, the highest pressure required at any point in time determines the pressure that all other services operate from. Valves reduce the pressure for each service individually, dissipating the energy difference as heat. By eliminating the need to dissipate power for multiple services in proportional valves, DD systems can often reduce overall energy consumption by as much as two thirds.

Perhaps even more important than the directly reduced in fuel or energy consumption, preventing excess pressure dissipation can eliminate the need for expensive cooling systems, dropping the overall system cost significantly.

Energy Regeneration

Digital Displacement® Pump/Motor cylinders can operate cylinders in motoring mode to recover energy from high pressure fluid services and add it to energy put in from the main shaft motor. For example, DD machines can reclaim energy stored in loaded hydraulic rams and route it to other services, or hydraulic storage accumulators for future use.

Idle Losses

Digital Displacement® machines have low idling losses because the reciprocating components are isolated from the high pressure services, because of careful flow and bearing optimisation, and because they can operate with a dry sump (no churning losses). Idling losses are typically around 1% of rated output power, making DD especially suitable for applications with low duty cycles but high peak power requirements. DD's ability to operate over a wide speed range can even further reduce idling losses by operating at reduced speed when appropriate.