f03a pump-motoreffiencies tmms10 (1)

7/22/2019 F03a Pump-MotorEffiencies Tmms10 (1)

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2009-03-23 Karl-Erik Rydberg

TMMS10,Karl-Erik Rydberg

Hydraulic pump/motor efficiencies

Volumetric losses

Leakage flow losses, ql p/

Compression flow losses , qc f()p/e

Hydromechanical losses

Friction losses (dry, viscous),Mff()p Pressure losses (line flow, acc.), p 2n2

Splashlosses (parts rotating in oil),Mfs n2


Volumetric losses in axial piston pumps

1-vp

Qep=pDpnpvp


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Hydro-mech. losses in axial piston pumps

11

hmp

hmp

pp

p pD

T

1

2=


Comparison of efficiency modelsIn-line pump, Sauer SPV 22

New model, Rydberg


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Results from new model: p

=1.0, p=35 MPa

In-line machines, Sauer


Results from new model: p=0.49, p=21 MPa

In-line machines, Sauer


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Volymetric pump efficiency

p = 1.0p = 0.5

p = 25 MPa

Pump speed [rpm]

Volumetricefficiency[-]

p = 1.0p = 0.5

p = 35 MPa

Pump speed [rpm]

Volumetricefficiency[-]


Constant power transformation by hydraulic motor(m=1, variable p / variable m, p=35 MPa)


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Optimal oil viscosity

Pump overall efficiency:

Dynamic oil viscosity () for maximumoverall efficiency:

High pressure drop (pd) and low speed (np) requires high viscosity!


Bent-axis motor overall efficiency fordifferent viscosities


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In-line pump overall efficiency for differentviscosities


Optimum viscosity range - Pump

The oil viscosity that

gives max overall

efficiency for an axial-

piston pump is

determined by itsspeed and pressure

difference.

Motors shows the

same characteristics.

Overall efficiency

Overall efficiency

Volumetric efficiency

Hydro-mechanical efficiency

Fluid viscosity [cSt]

Fluid viscosity [cSt]

np =500 rpm

np =3000 rpm

vp

hmp

vphmp

vphmp

vphmp


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Efficiency at partial torque loading


Motor shaft speed [rps]

Relativetorqueloss

es,

Tf/

Ti

Motor displacement setting =1, p =35 MPa

Hydro-mechanical motor lossesRelative torque losses

( )

pn

n

ppb

m

m

LmHm

+

+

0

4

1


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Sauer SMV 24 =1,0

Relative torque losses In-line motor( )

LH

LH

ppp

pn

pp

=

+

+

0,167,1

1

241077,49,0

2

Low speedlosses


Saw Motor with Power Boost - Parker

Parker

Power

BoostTM

mt 0,83(Theoretical power)

mt 0,76


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High efficient pump - Axial Piston Pump Based on theFloating Cup Principle, Peter Achten, Innas BV

Total efficiency of the floating cup

pump, Dm = 28 cc/rev, ti lt ang le = 8o


Qualification tests of hydraulic machines

Log(p)

Log(n)

Rotating parts

Rollerbearings

Others

Life length curve

High pressure, medium speed: Rotating parts criticalMedium pressure, high speed: Roller bearings criticalLow pressure, very high speed: Other parts critical


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Different tests for pumps and motors High pressure test

Pressure pulsation test at zero speed

High power test (long time test)

Flywheel test motor with flywheel (m =1.0)

Displacement setting test (motor loaded with a flywheel)

Acceleration test as motor (25000 40000 rad/s2)

High speed test overrunning capacity Low speed test for motors

Low temperature test

f03a pump-motoreffiencies tmms10 (1)

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