© Blue Graphics Concept Sauer-Danfoss Basic Hydrostatic (closed circuit) Introduction, July 2012.

© Blue Graphics Concept Sauer-Danfoss

© Blue Graphics Concept Sauer-Danfoss

Basic Hydrostatic (closed circuit)

Introduction, July 2012

2

MENU

What do you know about a closed circuit?

Components?Applications?

Advantage?

Only one fact per participant

3

MENU

Main Menu


Exposition closed circuit

Definition Pump and

Motor

Diesel EngineAdvantages Comparison to

torque converter

4

MENU

Main Menu



Definition Pump and

Motor


torque converter

5

MENU

Exposition of the closed circuit

Production

MENU

Pump and motor form a „Hydrostatic Transmission“

6

MENU

Main Menu



Definition Pump and

Motor


torque converter

7

MENU

Definition: Pump/Motor

Production

MENU

• PumpTransport of fluids and gases. At the same time transforming mechanical power into hydraulic power.

• MotorPerforms mechanical work by transforming hydraulic power into mechanical power.

8

MENU

Main Menu



Definition Pump and

Motor

Diesel Engine

Advantages Comparison to torque

converter

9

MENU

Diesel Engine in Mobile Work Machines

Production

MENU

Attributes:• Steady engine speed at partial load condition• Maximum engine power at maximum load condition• Increasing engine speed increases power due to roughly

constant engine torque • Direct drive vehicles (w/o transmission) have low

acceleration • It‘s recommended to use a transmission between the

engine and final drive • In this case it is recommended to use:

„Hydrostatic Transmission“

10

MENU

Main Menu



Definition Pump and

Motor


torque converter

11

MENU

Advantages of Hydrostatic Transmission MENU

Flexibility

High power density

Hydrostatic Braking

Continues variable

transmission

Hydrostatic

Transmission

Variable and constant speed

of engine

Adjustable/ Programmable

12

MENU

Advantages of Hydrostatic Transmission

Flexibility

MENU

Flexibility

High power density

Hydrostatic Braking

Continues variable

transmission

Hydrostatic

Transmission


of engine


13

MENU


Flexibility

MENU

• Independent arrangement of pump(s) and motor(s)

• Power transfer via hoses from pump to motor

• Independent arrangement of the Engine

• Pump arrangement as stacks or assembled to splitter box

• Wide transmission ratio

14

MENU


Continues Variable Transmission

MENU

High power density

Hydrostatic Braking Hydrostatic

Transmission


of engine

Continues variable

transmission

Flexibility


15

MENU


Continues Variable Transmission

MENU

• Continuously variable speed w/o loss of traction • No clutch is required to change the vehicle direction from

forward to reverse

Mechanical transmission Hydrostatic transmission

A

BSpeed [km/h]

Tra

cti v

e F

orc e

[N]

Pump Ratio Motor Ratio

Installed Engine Power

- source 1 - - source 1 -

16

MENU


Hydrostatic Braking

MENU

High power density

Continues variable

transmission

Hydrostatic

Transmission


of engineHydrostatic

Braking

Flexibility


17

MENU


Hydrostatic Braking

MENU

• The engine braking power is the capability of the engine to absorb the braking power of the hydrostatic transmission

• Vehicle braking capability depends on engine braking power• Lower level of engine braking capability for new tier IV diesel

engines

pumpmotor

acceleration

principle of operation:

pump motor

deceleration/

braking


- source 2 -

18

MENU


Hydrostatic Braking

MENU

• If the vehicle braking power requirement exceeds the engine braking power capability the engine can overspeed and could be damaged

motorpump

deceleration/

braking


19

MENU


High Power Density

MENU


Hydrostatic Braking

Continues variable

transmission

Hydrostatic

Transmission


of engine

Flexibility

High power density

20

MENU


High Power Density

MENU

• Power density is the relationship between power and package size

• Engine (here 90 kW) has lower power density than the hydrostatic pump (here H1P089)

21

MENU


Further Details

MENU

Hydrostatic Braking

Continues variable

transmission

Hydrostatic

Transmission

Flexibility


High power density


of engine

22

MENU

Main Menu



Definition Pump and

Motor

Diesel EngineAdvantages Comparison

to torque converter

23

MENU

Comparison HST vs. Torque Converter

Torque Converter construction

MENU

- source 2 - - source 2 -

Turbine Impeller Turbine Stator Impeller

Stator

25

MENU

Comparison HST vs. Torque Converter

Overview

MENU

Description Hydrostatic Torque Converter

Drive Train Design / Layout Flexible Fixed, in line Programmability of Drive Behavior

Programmable Fixed Traction Control Yes Suboptimal Shifting Drive Direction Without wear With wear Blocked Drive Train No Problem Overheating Variation of Transmission Ratio Without wear With wear Braking Capability Yes No Power Out Distribution Programmable Fixed Drop of Engine Speed (lug, stall) 100% traction force 70% traction force

Hill-Hold-Function w/ engine off 100% traction force NONE

Fast driving capability With additional gear included

26

MENU

Comparison HST vs. Torque ConverterMENU

HST & AC Torque Converter

Drive Train Design flexible (+) fixed, in-line package (-)

Hoses allow flexible arrangement of pump and motor

27

MENU



Driving Behavior programmable (+) fixed (-)

• Adjustable drive curve for Control for example the ACII Control for the Pump with different programmable driving curves

Sw

ash

pla

te a

ng

le

01

3 45

6

2

7

Engine rpm

Cu

rren

t m

A

28

MENU



Traction Control yes (+) limited (-)

• Tractive force of Torque Converter is depending on differential speed

• Tractive force of HST is controllable

29

MENU



Shifting Drive Direction

w/o clutch (+) w/ clutch (-)

• Shift of the Drive Direction with HST is possible by shift stroke of pump to opposite side

• Shift of the Drive Direction with Torque Converter only by shift a gear and use a clutch

• Clutch is a component with wear

30

MENU



Blocked Drive Train no problem (+) overheating (-)

• Blocked Drive Train is similar to drive against a wall, drive train speed at working engine

• HST will destroke the pump to zero degree*• Torque Converter will be overheated by a large differential

speed

*with Pressure Limiter

31

MENU



Transmission Ratio continues (+) mech. shifting gears (-)

• Torque Converter requires a mechanical gear shift transmission to reach the required transmission ratio

• HST has a large transmission ratio

32

MENU



Braking capability yes (+) limited (-)

Power output Distribution forpropel and auxiliary

programmable (+) fixed (-)

• HST is programmable to react on drop in diesel engine speed by drive of auxiliary machines

33

MENU



Drop of Engine Speed

100% traction force (+)

70% traction force (-)

• Torque Converter is direct depending by drop of engine speed

34

MENU



Fast driving capability

With additional gear (+)

Included (+)

35

MENU

The EndMENU

36

MENU

Overview Literature SourcesMENU

- Source 1 - Ölhydraulik – Handbuch für die hydrostatisch Leistungsübertragung in der Fluidtechnik; Findeisen,

D.; Springer - Source 2 - Hydrodynamische Antriebskomponenten in

Forstschleppern; Jörg Hittenbeck; IFA- Source 3 - http://de.wikipedia.org/wiki/Drehmomentwandler- Source 4 - http://de.luk.de

Date post:	18-Dec-2015
Category:	Documents
Upload:	ashley-gregory
View:	222 times
Download:	4 times

© Blue Graphics Concept Sauer-Danfoss Basic Hydrostatic (closed circuit) Introduction, July 2012.

Documents