The Shell Oil life exTenSiOn TOOl

Shell Marine Products
The Shell Oil Life
Extension Tool
Helping you to get the most from your
four‐stroke trunk-piston engines
Find out more
For more information about the Oil Life Extension Tool service, please contact your Shell Marine Products technical
manager or email to smp-marketing@shell.com or visit www.shell.com/marine/technical.
We can also offer you specialist lubrication solutions for a wide range of applications. Visit www.shell.com/marine
for more information.
© Shell International Petroleum Company Limited 2013. All rights reserved.
Issued February 2013

The Shell Oil Life Extension Tool
The properties of oil change when it is exposed to the working conditions in an engine and
these changes have a direct effect on engine performance. The concept of oil stress helps us to
understand why these changes occur, to assess the extent of the changes, and to identify the
factors responsible. The Shell Oil Life Extension Tool uses oil stress theory to help you optimise the
operation of your four-stroke trunk-piston engines with Shell Argina oils.
Understanding oil stress in
medium‐speed engines
There are three principal stresses that have an impact on the
performance of four-stroke trunk-piston engine oils: acid stress,
thermal stress and asphaltene stress. The level of oil stress in an
engine depends on the operating conditions, the volume of oil that
is available to absorb the stresses and the frequency with which the
oil is changed.
Recent trends in the design and operation of four-stroke trunk-piston
engines include higher-performing engine designs, a wider variety of
operating conditions and lower-quality fuels of increasingly variable
composition. Each of these changes can, if not correctly managed,
contribute to increased oil stress, which has a direct influence on
engine performance and operational costs. High oil stress can
■■
reduce engine reliability
■■
shorten oil life
■■
shorten the life of your engine components
■■
increase running costs.
Shell researchers have extensively tested engines and lubricants
under extreme conditions in order to understand and define various
aspects of oil stress. This research has enabled Shell to devise better
ways to manage oil stress and so improve engine reliability, extend
component life and reduce operating costs.
Key to controlling oil stress is selecting a lubricant that offers the
best all‐round stress management performance. Shell has used the
knowledge gained from its research to develop the Shell Argina
range of oils to address the challenges of acid, thermal and
asphaltene stress.
Introducing the Shell Oil Life
Extension Tool
Shell’s Oil Life Extension Tool uses oil stress theory to help customers
who want to get the best out of Shell Argina or who are face significant
challenges in the operation of their four-stroke trunk-piston engines.
Using a proven methodology, the Oil Life Extension Tool has
applications across a wide range of marine settings and scenarios.
Experience gained in applying the Oil Life Extension Tool has shown
that it can play a significant role in addressing the issues associated
with oil stress and extending the oil-drain interval.
benefits of the Oil Life Extension Tool
Oil stress levels are influenced by several factors, for example:
■■
the power developed by the engine
■■
the sulphur content of the fuel
■■
the lubricating sump volume
■■
the lubricating oil consumption rate.
Using values for these inputs in the Oil Life Extension Tool, Shell
representatives can provide tailored lubrication advice on oil stress
management in four-stroke trunk-piston engines. This helps engine
operators to
■■
select the grade of Shell Argina that matches the oil stress in
their engines
■■
achieve operational reliability
■■
reduce lubrication costs
■■
find greater peace of mind.
When can the Oil Life Extension
Tool help?
The Oil Life Extension Tool can help marine engine operators who
■■
have problems maintaining the quality of their oil charge.
■■
want to help ensure that they are minimising lubrication costs while
maintaining the operational health of the engine.
How do operators use the Oil Life
Extension Tool?
The oil change interval for trunk-piston engines is set by the
equipment manufacturers’ recommendations on drain interval.
However, monitoring key indicators such as residual base number
(BN) and viscosity through used oil analysis and setting the limits
that trigger oil change can extend the interval. It is also known that
the residual BN of an oil change in a trunk piston engine sump
corresponds very closely to the build-up of oil stress factors at any
given time. The Oil Life Extension Tool helps operators to identify the
optimal oil-drain interval.
The Oil Life Extension Tool models the time-based decay of properties
such as oil charge residual BN to assess and compare the lubrication
costs of possible oil replenishment strategies over a year or more of
engine operation. The options that can be modelled include
■■
selecting different Shell Argina grades to predict their effect on the
oil-drain interval
■■
conducting complete oil changes once safe limits are triggered
■■
conducting partial oil changes
■■
using sweetening (draining and replenishment of small, calculated
amounts of oil charge at specified intervals) to delay full or partial
oil changes.
Operators can use the Oil Life Extension Tool in three distinct
ways. At the first level, the Oil Life Extension Tool enables users to
estimate the BN as a function of the running hours for Shell Argina
lubricants and to create a running hours versus oil BN curve using
simple technical information such as engine output, oil volume in
circulation, oil consumption and the sulphur content of the fuel.
BN depletion graph
MV
BN
Sirius,
depletion
Wärtsilä
graph
6L38A
MV Sirius, Wärtsilä 6L38A
55
55
50
50
45
45
40
40
35
35
30
30
25
25
20
20
15
15
10
10
5
5
0
0 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000
0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000
Oil usage time (h)
Oil usage time (h)
BN rejection limit
Shell BN rejection Argina XL, limit fresh oil BN: 50, fuel S: 2.3%, SLOC: 0.36 g/kWh, eq. BN: 16.3
Shell Argina X, XL, fresh fresh oil oil BN: BN: 40, 50, fuel fuel S: S: 2.3%, SLOC: 0.36 0.36 g/kWh, eq. eq. BN: BN: 6.3 16.3
Shell Argina X, fresh oil BN: 40, fuel S: 2.3%, SLOC: 0.36 g/kWh, eq. BN: 6.3
BN BN (mgKOH/g)
BN depletion graph
MV
BN
Sirius,
depletion
Wärtsilä
graph
6L38A
MV Sirius, Wärtsilä 6L38A
55
55
50
50
45
45
40
40
35
35
30
30
25
25
20
20
15
15
10
10
5
5
0
0 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000
0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000
Oil usage time (h)
Oil usage time (h)
BN rejection limit
Shell BN rejection Argina XL, limit fresh oil BN: 50, fuel S: 2.3%, SLOC: 0.36 g/kWh, eq. BN: 16.3
Measured Shell Argina XL, fresh oil BN: 50, fuel S: 2.3%, SLOC: 0.36 g/kWh, eq. BN: 16.3
Measured
BN BN (mgKOH/g)
Cost of lubrication over observed period
MV
Cost
Sirius,
of lubrication
Wärtsilä 6L38A
over observed period
MV Sirius, Wärtsilä 6L38A
55
55
50
50
45
BN (mgKO BN 25 20
20 15
15 10
10 5
50
0 1,000
0
0 1,000
2,000 3,000 4,000 5,000 6,000 7,000 8,000
2,000 3,000
Oil
4,000
usage time
5,000
(h)
6,000 7,000 8,000
There is also the option of inputting measured BN values on the
BN rejection limit
Oil usage time (h)
estimated Shell Argina BN decay XL, fresh oil curve BN: 50, so fuel that S: operators 2.3%, SLOC: 0.36 can g/kWh, gain confidence
eq. BN: 16.3
BN
in the Shell
rejection
effectiveness Argina
limit
X, fresh of oil the BN: tool. 40, fuel S: 2.3%, SLOC: 0.36 g/kWh, eq. BN: 6.3
Shell Argina XL, fresh oil BN: 50, fuel S: 2.3%, SLOC: 0.36 g/kWh, eq. BN: 16.3
Shell Argina X, fresh oil BN: 40, fuel S: 2.3%, SLOC: 0.36 g/kWh, eq. BN: 6.3
At the second level, the Oil Life Extension Tool can model lubricant
BN depletion graph
expenditure based on input values for lubricant unit price,
normal BN
MV
depletion
Sirius, Wärtsilä
consumption graph
6L38A
(replacing what is consumed) and artificial
MV
consumption.
55 Sirius, Wärtsilä 6L38A
This can help operators decide to improve the oil
quality 55 50
by either complete and regular oil changes or more frequent
oil 50 sweetening.
45
45 40
The third level option for the Oil Life Extension Tool calculates the
40 35
lubrication cost if the engine operator does not conduct a partial oil
35 30
change but increases the oil-sweetening rate. Sweetening involves
30 25
draining a small amount of oil regularly (daily or every few days)
25 20
before topping up. This introduces more fresh oil into the engine
20 15
than would be required to compensate for the natural consumption
15 10
of the engine and will result in the lowest cost of lubrication at a
10 5
given grade. The program calculates the volume of oil that needs
50
to be 0drained 1,000every 2,000 day 3,000 and the 4,000 overall 5,000 cost of 6,000 lubrication. 7,000 8,000
0
Oil usage time (h)
The Shell
0
Oil
1,000
Life
2,000
Extension
3,000
Tool
4,000
can help
5,000
you
6,000
to get the
7,000
best
8,000
out
BN rejection limit
Oil usage time (h)
of Shell Argina or meet the challenges of operating your four-stroke
Shell Argina XL, fresh oil BN: 50, fuel S: 2.3%, SLOC: 0.36 g/kWh, eq. BN: 16.3
trunk-piston BN Measured
rejection engines.
limit
BN (mgKOH/g)
BN (mgKOH/g)
Cost of lubrication over observed period
Cost
MV Sirius,
of lubrication
Wärtsilä 6L38A
over observed period
MV 55 Sirius, Wärtsilä 6L38A
55 50
50 45
45 40
40 35
35 30
30 25
25 20
20 15
15 10
10 5
50
0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000
0
0 1,000 2,000 3,000Oil 4,000 usage time 5,000 (h) 6,000 7,000 8,000
BN rejection limit
Oil usage time (h)
BN Shell Argina XL, partial replacement:15%, total volume: 19267 L, total cost: USD33,717
Shell rejection Argina X, limit partial replacement:15%, total oil volume: 25,207 L, total cost: USD50,413
Shell Argina XL, partial replacement:15%, total volume: 19267 L, total cost: USD33,717
Shell Argina X, partial replacement:15%, total oil volume: 25,207 L, total cost: USD50,413
BN (mgKOH/g)
BN (mgKOH/g)
Optimal lubrication practice with given grade,
Optimal
cost of lubrication
lubrication
over
practice
observed
with given
period
grade,
cost
MV Sirius,
of lubrication
Wärtsilä 6L38A
over observed period
MV 55 Sirius, Wärtsilä 6L38A
55 50
50 45
45 40
40 35
35 30
30 25
25 20
20 15
15 10
10 5
50
0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000
0
0 1,000 2,000 Oil 3,000 usage 4,000 time (h) 5,000 6,000 7,000 8,000
BN rejection limit Oil usage time (h)
Shell Argina XL, sweetening 5 liter/day after 9222 hrs, total volume: 19,029 L,
BN total rejection cost: USD33,300 limit
Shell Shell Argina X, XL, partial sweetening replacement: 5 liter/day 15%, after total volume: 9222 hrs, 25,207 total volume: L, total cost: 19,029 USD50,413 L,
total
Shell
cost:
Argina
USD33,300
X, sweetening 26 L/d after 3,754 h, total volume: 23,867 L, total
Shell cost: Argina USD47,734 X, partial replacement: 15%, total volume: 25,207 L, total cost: USD50,413
Shell Argina X, sweetening 26 L/d after 3,754 h, total volume: 23,867 L, total
cost: USD47,734
BN (mgKOH/g)
BN (mgKOH/g)
Shell Argina XL, fresh oil BN: 50, fuel S: 2.3%, SLOC: 0.36 g/kWh, eq. BN: 16.3
Measured