"Lube System Modelling and

Validation, Including a

Detailed Lube Pump"

14 November 2016

Riccardo Meldolesi, Clive Lacy

Contents

Engineering Program Details

Baseline engine characterisation – Comparison with measurements

Engine upgrade - Technologies to reduce oil demand

Engine upgrade - Comparison with measurements

Conclusions

Appendix 1 - Detailed gerotor pump modelling

Appendix 2 - Variable Displacement Vane Pump modelling

2

Engineering Program Details

1. Use of GT-SUITE to characterise the lube system of an

existing baseline engine & correlate to measured pressure

versus flow data

2. Extended model to perform oil pump sizing for new but

similar engine version

– Reduced idle speed

– Different block layout, new filter & cooler

3. Investigated technologies to reduce engine oil flow

requirement

– Minimise friction & pump size

– Investigate Packaging a Variable Displacement Vane Pump (VDVP)

3

Engine Features

Gasoline, Port fuel injection

4 Cylinder 2.3 litre, turbocharged

Cast iron block with aluminium head

Gerotor oil pump

Piston cooling jets (x4)

Twin balancer shafts (plain bearings at each end)

Type 1 Valvetrain with Hydraulic lash adjusters

(x16)

Intake & exhaust cam phasers

4

5

Base Engine

Pressure Vs Flow

characteristics

6

Baseline Lube Model - Features

Modelled “flow users” first:

Bearings, PCJs, Valvetrains, phasers,

Timing drive, Turbo

Temperature dependent clearances

– At Cam bearing & HLA bore, based

on thermal FEA results

Detailed piston cooling jet model (flow

test data was available)

Speed dependent bearing loads (look-up

tables)

Cam phaser oil control valve (OCV)

leakage based on measurementsBlock

Camshafts

Model showed correct pressure-flow sensitivity to temperature ‘out of the box’

7

Baseline Engine Model – Correlation

0 10 20 30 40 50 60 70 800

2

4

6

8

Flow [l/min]

[Ba

r, g

au

ge

]

Flow into Engine / Main Gallery Pressure

0 10 20 30 40 50 60 70 800

2

4

6

8

Flow [l/min]

[Ba

r, g

au

ge

]

Main Gallery Pressure Versus Flowrate

1000 rpm

1500 rpm

2000 rpm

2500 rpm

3000 rpm

B236

Meas., 3000rpm 125°C

Meas.105°C

Meas.3000 rpm 80°C

Meas.95°C

8

New Engine

Contents Definition

Block

Front cover circuitry & pump

9

Lube Model of New Engine

Min. Clearance

Mean Clearance

Max. Clearance

2/3rds Mean to Max.

Definition of 2/3rds Mean to

Max Clearance

GT-Suite Model extended to include:

Exact circuitry from CAD (GEM 3D tool used)

New oil cooler (supplier measured ∆P Vs

flow)

– ‘FlowPDropTableRef’ Object used to

ensure correct ∆P Vs temperature

response

New oil filter (supplier measured ∆P Vs flow)

– Modelled with a ‘PipeCrossSection’ object

– Pressure drop vs. flow rate close to linear

Detailed model of pressure relief valve (PRV)

Detailed lube pump leakage model (next

slide)

Camshafts

10

Sub-model of pump internal leakages

Built to generate pump vol. eff. maps at different oil temperatures

– Leakages strongly affected by oil temperature at lower speeds

• Viscosity & clearances

– Filling / cavitation effects more dominant at high speeds

Cavitation effects derived form measurements (VolEff @ 0 ∆P)

Good match of ∆P Vs Flow gradients to pump bench tests(102°C)

PRV open

Temperature dependent gradients

Gerotor Pump Maps Generation

Technologies to Reduce Oil Demand

11

0

5

10

15

20

25

30

Req

uir

ed P

um

p C

apac

ity

[cc/

rev]

Assumes 80% pump efficiency

Build #1 Build #2 Build #3 Build #4 Build#6

Baseline Graded Graded Graded Graded Main bearing

Baseline BaselineReduced max.

clearance

Rolling element

bearing

Rolling element

bearingRear balancer bearing only

Hydraulic Hydraulic Hydraulic Hydraulic Mechanical Tappets

130°C 130°C 130°C 130°C 130°C0

10

20

30

40

Engine Speed: 700 rpm

Flo

w C

on

trib

utio

n [

%]

GP: 0.85 bar

Total: 14.9 l/minGP: 0.79 bar

Total: 12.2 l/minGP: 0.84 bar

Total: 11.5 l/minGP: 0.86 bar

Total: 10.4 l/minGP: 0.93 bar

Total: 7.7 l/min

0 2 4 6 8 10 120

5

10

15

20

Engine Speed: 3000 rpm

Main Bearings

Conrod Bearings

Balancer Bearings Front

Balancer Bearings Rear

HLAs

Piston Cooling

Camshaft Bearings

Turbo Leakage

Phasers

Other

130°C 130°C 130°C 130°C 130°C0

1

2

3

4

5

Engine Speed: 700 rpm

Flo

w R

ate

[l/

min

]

GP: 0.85 barTotal: 14.9 l/min

GP: 0.79 barTotal: 12.2 l/min

GP: 0.84 barTotal: 11.5 l/min

GP: 0.86 barTotal: 10.4 l/min

GP: 0.93 barTotal: 7.7 l/min

Main Bearings

Conrod Bearings

Balancer Bearings Front

Balancer Bearings Rear

HLAs

Piston Cooling

Camshaft Bearings

Turbo Leakage

Phasers

Other

0 2 4 6 8 10 120

5

10

15

Engine Speed: 3000 rpm

Main Bearings

Conrod Bearings

Balancer Bearings Front

Balancer Bearings Rear

HLAs

Piston Cooling

Camshaft Bearings

Turbo Leakage

Phasers

Other

Selected Build (~30% lower flow

than baseline)

OBJECTIVE:

minimise oil pump required

size for reduced losses, &

potentially enable packaging of

a variable displacement vane

pump (VDVP)

700 rpm

130 °C Oil T

0.85 bar Gallery Pressure (GP)

target

12

New Engine

Correlation Check

To flow meter

Lube System & Instrumentation Layout

13

Flo

2.4 mm orifice restrictors installed to control Head oil flow

Spacer block to allow pressure and temperate measurements pre

and post oil cooler

Head machined for pressure & temperature measurement at the ‘head to block’ location

Cam cover machined for pressure measurement of cam phaser OCV circuit pressure

Fittings at the rear of the head installed to measure head gallery pressures (intake & exhaust)

Oil filter adapter machined to install a oil flow meter

1

2

34

5

6

78

[Ba

r G

auge

]

Pump Outlet Pressure vs. Engine Flow Rate at 90°C

5 10 15 20 25 30 35 401

2

3

4

5

6

7

[litres/min]

[Ba

r G

auge

]

Main Gallery Pressure vs. Engine Flow Rate at 90°C

Sim. Clr Range

Sim. Mean Clr.

Measured

Comparison with Measurements

14

‘Out of the box’ Simulation results

Simulated pressure vs. flow at mean clearances good match to measured data

2/3rds Mean to Min.

2/3rds Mean to Max.

Simulated

0

1

2

3

4

5

6

7

[Ba

r G

auge

]

Cylinder Block Main Gallery: 90°C

Cylinder Block Main Gallery: 130°C

1000 2000 3000 4000 50000

1

2

3

4

5

6

7

Engine Speed [rpm]

[Ba

r G

auge

]

Cylinder Head (Exhaust End): 90°C

1000 2000 3000 4000 5000Engine Speed [rpm]

Cylinder Head (Exhaust End): 130°C

Sim. Clr Range

Measured

Sim. Mean Clr.

15

Comparison with Engine Measurements

Measured results closer to 2/3rds mean to max. bearing clearance case at both temperatures

Since pressure vs flow correlates well with mean clearances (previous slide) this suggests the pump volumetric efficiency in the engine may be lower than predicted

Pump & PRV clearances to be measured at first engine inspection teardown.Pump bench testing might also be required

PRV Model needs tuning

Close agreement at critical hot idle

case

2/3rds Mean to Min.

2/3rds Mean to Max.

Summary

GT-SUITE has been successfully used to fully model the lube system of a new engine

design

The model was built to characterise the highly temperature dependent pressure vs flow

characteristic measured on an existing baseline engine

– Obtained correct pressure-flow sensitivity ‘out of the box’

The model also was used to investigate technologies for flow reduction (hot idle) to

minimise pump size & power consumption

A new gerotor oil pump capacity required was determined for the new engine

Simulation results show very good agreement with measured pressure vs flow, work is

on-going to investigate some lower than expected pressures versus engine speed

In addition, a variable displacement vane pump (VDVP) is being investigated for

packaging & performance and fitting on future engine versions. Work is ongoing

16