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"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
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