Why Hydraulic Fan Drive?

In this post, fan drive solution with differentpump & Motor configuration will be investigated a little bit. Solutions from the most popular suppliers: Danfoss,Rexroth and Parker are illustrated.

>>>> Why Hydraulic Fan Drive >>>>
Increasing governmentregulations on Tier III and IV diesel emissions require engine fan drivesolutions with significantly higher cooling ability and more precise temperaturecontrol. Engine cooling systems need to be highly efficient to conserve powerand fuel for the vehicle. In addition, these systems need to be quiet andreliable. An integral part of the engine cooling system is the fan drive system,and hydraulic fan drive systems are an excellent solution to meet thesedemands.
· Flexible installation
Witha fan that isn’t tied to the drivetrain, the cooler can now be located at anyplace in the vehicle. This can result in better air flow and lower installationcosts.

· Reduced PowerConsumption
Traditional direct-driveengine mounted fan systems consume excess power because the fan speed isdependent on the engine speed. As the engine speed changes, the fan is oftendriven faster than what is required to cool the engine. This inefficiency isvery significant especially at high fan speeds. In addition, direct-drive systemshave difficulty achieving high cooling levels at low engine speeds.

· Increased Control
A hydraulic fan drivesystem allows variable fan speed independent of the engine speed.
It provides only thecooling that is required throughout the operating range of the vehicle,including where high cooling may be required at lower than maximum enginespeed. The full cooling control of hydraulic fan drives enables ramping of thefan speed command to avoid shock and to idle the fan during engine startup topreserve power. Hydraulic fan drive systems enable better fan control, yieldingsignificant power and fuel savings.

>>>> Danfoss Hydraulic Fan Drive Solutions>>>>

Danfoss offers a complete range of both open circuit andclosed circuit fan drive systems:
Fan drives < 50hp: Gear pumps and motors
Fan drives 50-100hp: Gear pumps and motors, S45 piston pumps, S40 piston motors
Fan drives >100hp: S45 and H1 piston pumps, S90 piston motors

§ Gear Pump (SNP) + GearMotor (SGMY)

§ Variable Piston Pump (S45w/ EPC) + Gear Motor (SNM)

§ Variable Piston Pump (S45w/ EPC) + Gear Motor (SNM) + HIC

§ Variable Piston Pump (S45w/ EPC) + Piston Motor (S40)

§ Variable Piston Pump (H1P)+ Piston Motor (S90)

Recently,Danfoss launched a new solution for hydraulic fan drive system: variable pistonmotor RDM with integrated flow reversing function plus variable piston pump S45with EPC function.

>>>> Rexroth Hydraulic Fan Drive Solutions>>>>

Rexroth hydrostatic fan drives are available in four different variants. For one thing,the fan drive can be hydraulically orelectrically controlled. For another thing, the fan can be driven by a fixed or variable system.

§ Rexroth hydraulic fandrive solution overview

§ Rexroth hydraulic fandrive solution configuration

Inthe post N2, the latest solution for fan drive system from Rexroth has already launched,the new variable piston pump A1VO is introduced in this solution which was alsoshown on Bauma 2014.

>>>> Parker Hydraulic Fan Drive Solutions>>>>

Parker provides threefan drive motor and pump technologies for the fan drive function. Three examplesystems are summarized and categorized as “Basic Efficient System, AdditionalPerformance and Optimized Performance”. The ”Basic Efficient” system can be consideredlower installed cost while still retaining the main hydraulic fan drivebenefits outlined earlier in this guide. The “Optimized Performance” system willhave the highest installed cost, but offers very distinct advantages when consideringthe environment, efficiency and life time cost.

§ Parker hydraulic fandrive solution – Basic Efficient System