Research Activities of LVK - ClassNK · Research Activities of LVK. Technische Universität München LVK ... Design of measurement techniques for tribological studies in the piston

Technische Universität München

LVKLehrstuhl fürVerbrennungskraftmaschinen

Research Activities of LVK



Engine Laboratory

2



Personnel

3

Head: Prof. Dr.-Ing. G. WachtmeisterAdministration / organization: 2 secretariesResearch and teaching: 2 senior engineer

29 scientific engineers 2 plant engineers

test bed technicianelectronic engineerelectronic technicianforeman

5 workshop-employees2 apprentices

research students



Testbeds

4

tb. 1 tb. 2 tb. 3 tb. 4 E-centre tb. 5 Roll tb. 6

tb. 8

1a

1b

2a

2b

3a

3b

4a

4b

5a

5b

250 kW9500 rpm

420 kW4000 rpm

70 kW8000 rpm

220 kW10000 rpm

380 kW9000 rpm

150 kW10000 rpm

80 kW7500 rpm

80 kW7500 rpm

44 kW6500 rpm

44 kW6500 rpm

700 kW5500 rpm

250 kW9500 rpm +380kW6000rpm asTandem

tb. 7

80 kW7500 rpm

dynamic asynchronous machineDC-machinemonitoring-roomeddy current brakewater brake

gas supplied



Agenda

• Overview of Project Acitivities

• Influence of H2 admission in lean burn gas engines

• Unburned Hydrocarbons of Gas Engines

• Oil Flow and Distribution at Piston/Piston Rings

5



Agenda





6



Field of Activities 1/4

7

Combustion prozess development

Diesel Otto Gas

Experimental Simulation Tools development

Injection

Spray Chamber

Thermodynamic engines

Engines with optical access

0D / 1D Simulation

CFD-Simulation

Combined CFD-FEM Calculation

Phenomenologicalcombustion models




8

Tribology of Piston / Piston Rings / Liner

Friction Measurements

Floating Liner

Oil Flow/Distribution at Piston and Liner

Experiment

• Movements of Rings andPiston

• Axial• Radial• Circumferential

• Pressure distribution withinring package

• Oil film thickness• Oil condition

Simulation

CFD-calculation• Blow By resp.

Reverse Blow By• Oil flow from

combustionchamber tocrankcase




9

Gas Engines

• Mini Combined and Power Unit• Lean burn Passenger Car Engine• Combustion Process Development

• Spark ignition• Prechamber• Pilot fuel

• Unburned Hydrocarbons• BMEP 30bar• Formaldehyde Emission• Dual Fual Combustion




10

Alternative Fuels

• Hydrogen• Biogas• Vegetable oil• Oxygenated Fuels



Partners

11

• FVV: Forschungsvereinigung Verbrennungskraftmaschinen (FVV-

Eigenmittel, Aif), German association of combustion engines manufacturer

and supplier

• BFS: Bayerische Forschungsstiftung (Bavarian research association)

• DFG: Deutsche Forschungsgesellschaft (German research foundation)

• Different research foundations (z.B. Projektträger Jülich, Fachagentur

Nachwachsende Rohstoffe)

• Industrial research i.e.



Agenda





12



Singe Cylinder Gas Engine Industrial Size

13

Characteristics of LVK – single cylinder gas engineBore 170 mm Mass Balancing 1. & 2. Order (Lancaster)

Stroke 210 mm Ignition SystemWoodward IC922 (360mJ / 30++kV) / Pilot-Injection /

LVK-Multisparc

Displacement 4,77 l Charge Air Supply Screw Compressor(6 bar abs. / 8 bar abs.)

Epsilon (adjustable) 12,7 Emission

Measurement SystemAnysco FT-IR / O2-

Analystor / FID

Peak Pressure 300 bar TurbochargerEmulation

Exhaust Throttle andFeedback Control of

Tubocharger Efficiency

Valve Train 4 Valves / 2 Camshafts Engine Speed Max. 2000 1/min /

Standard 1500 1/min

Variable ValveTiming Miller / Atkinson Variable Mixture of

Fuel Gas

Propan, CO2, H2, N2 in Natural Gas (Analysis with

Gas Chromatograph)



Test Boundary Condition

14

• Natural gas composition (Munich city gas)

• H2 volume : 0, 10, 20, 30 vol.%

Operating conditions

• Air mass flow constant• IMEP : 18 - 20 bar• Turbocharger efficiency : 75%



Combustion Stability

15



THC-Emission

16



NOx-Emission

17



Indicated Efficiency

18



Agenda





19



Influence of Equivalence Ratio and Combustion Phasing

20

Efficiency-THC trade-off at MFB50%-variation Insufficient compensation ofburning efficiency losses (laterMFB50%) by higher fuelconversion rate

Efficiency-Optimumfor NOx TA Luft



Ignition System

21

Spark-Plug Prechamber (unscavenged)

Extended operating range (lean and knock limit) with prechamber

Lower NOx levels reachable

Earlier COC at constant NOx attainable



Ignition System

22

Spark-Plug Prechamber (unscavanged)

Same level of efficiency at lower THC (lines)

Vice versa: same level of THC at higher efficiency

Higher THC-Level at max. efficiency due to leaner mixture

Operation with prechamber:



Mixture Formation

23

Venturi mixer withcrankangle-synchronic

gasinjection

Perforated downpipe

Modified reciever-pipe for PFI-Mode

PFI-Duct-Geometry

Gas supply

Gas-Air-Mixture



Mixture Formation

24

Mixture formation via homogenizer Port-Fuel-Injection

Additional Info.: Operating range comparable; COC slightly later due to knocklimit with PFI-Mode

Increased THC (and CO) due to local too lean and rich mixture with PFI-Mode

Homogeneos mixture should be intended



Optical Set-up

25

95 mm

Piston Bowl (cylindrical)

Elongatedcomposite piston

Quartz glassinsert

Line of sight w.high speed cam.

Dry runningpiston rings and bearing

strip



Optical Investigations of the First Flame Propagation

26

Average Flame

Probability Distribution* [% of cycles]

*Dark red means that the flame is present in 100 % of the cycles at the shown crank angle



Agenda





27



Project Overview

28

2013 2014 2015

► Design of measurement techniques for tribological studies in the piston ring area

Design of a single cylinder petrol engine and measurement technologies

Lubricating Oil film thickness, Oil transport and distribution, Piston secondary and piston

ring movement, Piston ring joint position, Ring land pressure, Component temperatures, Blow-By

Test and validation of measurement technologies

Sta

rt K

olbe

nrin

g-Ö

ltran

spor

t 2…

Fired Engine

Operation

Sta

rt K

olbe

nrin

g-Ö

ltran

spor

t 1…

for



Research Engine

29

Timing driveCylinder head

Crankcase

Mass balancing

Cylinder and liner

Engine frame with oil conditioning &coolant conditioning

Engine data ValueBore x stroke 82,5 mm x 92,8 mm

Standard components Piston, conrod

Timing drive2 inlet valves,

2 exhaust valvesMaximum peak

pressure 110 bar

Compression ratio 9,5 : 1

Maximum engine speed6500 rpm

(with measurement link 4000 rpm)

Flywheel mass 1,5 kgm²Mass balancing 1. and 2. engine order



Data Transfer via Grashopper Link

30

Crankcase

Measurement link case

∆α (Joint1)

∆β (Joint 2)

∆γ (Joint 3)

TDC -BDC

26,7° 5,6° 32,2°

Optical fiber connectorWire connector

BDC

TDCα

α β

β

γ

3

2

1

2

1

stro

keCylinderLiner

Thermocouples, Capillary tubes



Optical Acess with Fiber Wires

31

Tube

PTFE ball

PTFE-Bearingshell

Length com-pensation

180° [CA] (BDC)90° [CA]0° [CA]

(TDC)

1 (b)

180°

support PistonTube

Bearing boxTubeSupport

1 (b) 1 (b)

1 (a)

Wires Optical fibers

2 2

2

Coupling arm

Optical fibers

Needle bearing

Wires

1 (a) 1 (a)

1

1

3

Tube Pin

Shaft nut

Pedestal Bearing

Link

Piston

Slide Bearing

Piston pin

Piston

Conrod

bush

Pin

screw

Conrod

Optical Fiber bridge



x<

32

0 180 360 540 7200

0.5

0 180 360 540 720

-0.1

0

0.1

1

x

yz

к

0,6 mm

TS skirt

TS top

Distance (+) Distance (-)ATS skirt

2000 [rpm]

0 180 360 540 720-2000

02000

0 180 360 540 7200510

0 180 360 540 720-0.2

00.2

3

[Nm

]

2

=I 0,05 mm I

motored5 bar IMEPAT

S s

kirt

TS to

pTS

ski

rtCA[°]

Dis

tanc

e [m

m]

Cold clearance: 0,09 mm (top) - 0,06 (bottom)



Circumferential Piston Ring Motion

33

TS ATS

AA

Cylinder

PistonLiner

Piston ring joint 1

Piston ring joint 2

TS ATS (0°)

40°50°

Measured with Co60

sample with 69 kBqin piston ring 2

A-A



Circumferential Piston Ring Motion

34

500 1000 1500 2000Engi

ne S

peed

[rpm

]

0100020003000

500 1000 1500 2000

IME

P

[bar

]

05

10

500 1000 1500 2000

Cou

nts

[1/s

]

0200400600

Time [s]500 1000 1500 2000A

ngle

of S

ampl

eto

ATS

[°]

-90090180

start

TS ATS (0°)

start



Oil Film Thickness with LiF

35

a.

a. Laser (1,5 W)b. 50/50 Beam splitter (15)c. Mirror (32)d. Dichroic Mirror (16)e. Fiber Coupling (16)f. Filter & Convex Lens

(16)g. Photodiode (16)

b.

c.c.

d.g.

e.

f.

To engine…From engine…



Measured Oil Film Thickness

36

CA [°]

Piston skirt

chamfer

>45 µm

2.4 - 3.4 µm1.6 - 2.6 µmCylinder

Liner

LIF-probe

½ stroke skirt

Optical Fibers

Coolant

Stro

ke[m

m]

Ferrule with optical fiber CA [°]

2000 [rpm]TDC PR1TDC PR2

TDC skirt

vmax skirt

BDC PR1

TDC OSR

BDC PR2BDC OSR



37

We have already achieved a high level insight into theindividual mechanisms of a combustion engine

We have pushed the combustion engine to a high mature level

But we still have a lot to do!



38

Many thanks for your kind attention

Particular thanks to

for the very fruitful cooperation

Documents

Research Activities of LVK - ClassNK · Research Activities of LVK. Technische Universität München LVK ... Design of measurement techniques for tribological studies in the piston