CEN/TR 17548:2020

Automotive fuels - Diesel fuel market issues - Abrasive particles investigation report

This document describes the investigation into diesel vehicle common rail fuel injection system damage and excessive wear problems in a number of countries across Europe since 2014 carried out by CEN/TC 19/WG 24 Abrasive Particles Task Force.

Kraftstoffe - Marktprobleme bei Dieselkraftstoff - Untersuchungsbericht zu abrasiven Partikeln

Carburants pour automobiles - Problèmes concernant le carburant diesel - Rapport d’enquête sur les particules abrasives

Goriva za motorna vozila - Področja trga dizelskih goriv - Poročilo o raziskavi abrazivnih delcev

General Information

• Status: Published
• Publication Date: 24-Nov-2020
• ICS: 75.160.20 - Liquid fuels
• Technical Committee: CEN/TC 19 - Petroleum products, lubricants and related products
• Drafting Committee: CEN/TC 19/WG 24 - Specification for automotive diesel
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 25-Nov-2020
• Due Date: 19-Aug-2021
• Completion Date: 25-Nov-2020
• Ref Project: SIST-TP CEN/TR 17548:2021 - Automotive fuels - Diesel fuel market issues - Abrasive particles investigation report

Overview

CEN/TR 17548:2020 (identical to CEN/TR 17548:2020) is a CEN Technical Report by CEN/TC 19/WG 24 documenting an investigation into abrasive particle contamination in diesel fuel and associated damage to high‑pressure common‑rail fuel injection systems across parts of Europe since 2014. The report compiles field failure data, fuel quality investigations and root‑cause analysis carried out by vehicle OEMs, fuel and component manufacturers and specialist laboratories.

Key topics and technical focus

• Scope and incidents: analysis of injector warranty claims and geographic clustering (notably Northern Germany, southeast UK, parts of France and Spain) and seasonal trends (peaks in winter months).
• Failure modes: internal injector damage leading to inner leakage, engine power loss, engine shutdown and idle instability.
• Particle size and clearance: recognition that common‑rail moving parts and valve seats operate with working clearances of about 1–4 µm, so particles <4 µm (including <1 µm) can cause severe wear; on‑board filters (typically 4–5 µm) cannot fully protect against these particles.
• Damage locations: solenoid valve seats, needle/valve sliding components, pressure regulating valves and other internal components are illustrated and documented.
• Investigative methods: fuel and component analyses, particle counting, filter blocking tendency (FBT) testing and chemical trace analysis techniques referenced (e.g., ICP‑AES, ICP‑MS) to characterise particulate contamination.
• Recommended practices: industry guidance covering good housekeeping, market surveillance, and reference to related guidance documents (e.g., CEN/TR 15367‑1, API 1640).

Practical applications - who should use this report

• Fuel suppliers and distributors - to assess market fuel quality risks and implement contamination prevention.
• Vehicle OEMs and fuel injection equipment manufacturers - for failure analysis, warranty management and specifying protective requirements (filtration, materials).
• Fuel testing laboratories and certification bodies - to adopt particle counting and FBT methods and interpret contamination data.
• Fleet operators and workshop/service organisations - to understand symptoms, diagnostics and maintenance implications.
• Standards committees and regulators - for shaping fuel quality standards, market surveillance and future work recommendations.

Related standards and keywords

• Normative reference: EN 590:2013+A1:2017 (Automotive fuels - Diesel).
• Related guidance: CEN/TR 15367‑1, API 1640.
• SEO keywords: diesel fuel quality, abrasive particles, common‑rail fuel injection, fuel injector wear, particle counting, filter blocking tendency, EN 590, fuel contamination investigation.

This Technical Report is a practical resource for stakeholders seeking evidence‑based findings on how microscopic abrasive particles in diesel fuel can damage modern common‑rail injection systems and what industry practices can reduce risk.

Standards Content (Sample)

SLOVENSKI STANDARD
01-februar-2021
Goriva za motorna vozila - Področja trga dizelskih goriv - Poročilo o raziskavi
abrazivnih delcev
Automotive fuels - Diesel fuel market issues - Abrasive particles investigation report
Kraftstoffe - Aspekte des Marktes für Deiseselkraftstoff - Untersuchungsbericht zu
abrasiven Partikeln
Carburants pour automobiles - Problèmes concernant le carburant diesel - Rapport
d’enquête sur les particules abrasives
Ta slovenski standard je istoveten z: CEN/TR 17548:2020
ICS:
75.160.20 Tekoča goriva Liquid fuels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TR 17548
TECHNICAL REPORT
RAPPORT TECHNIQUE
November 2020
TECHNISCHER BERICHT
ICS 75.160.20
English Version
Automotive fuels - Diesel fuel market issues - Abrasive
particles investigation report
Carburants pour automobiles - Problèmes concernant Kraftstoffe - Marktprobleme bei Dieselkraftstoff -
le carburant diesel - Rapport d'enquête sur les Untersuchungsbericht zu abrasiven Partikeln
particules abrasives
This Technical Report was approved by CEN on 2 November 2020. It has been drawn up by the Technical Committee CEN/TC 19.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 17548:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Symbols and abbreviations . 5
5 Description of fuel injection equipment problems . 6
6 Fuel injection system damage investigations . 15
7 Fuel quality investigations . 22
8 Particle counting . 54
9 Filter Blocking Tendency . 65
10 Recommended industry practices . 67
10.1 Good housekeeping practices . 67
10.2 CEN/TR 15367-1 . 67
10.3 API 1640 . 67
11 Modern diesel vehicle injection system technology . 67
12 Discussion . 68
13 Conclusions . 74
14 Future work. 76
Bibliography . 77

European foreword
This document (CEN/TR 17548:2020) has been prepared by Technical Committee CEN/TC 19 “Gaseous
and liquid fuels, lubricants and related products of petroleum, synthetic and biological origin”, the
secretariat of which is held by NEN.
This document primarily addresses quality issues that can be associated with abrasive particles in diesel
fuel that can cause wear damage to high pressure common rail fuel injection systems.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Introduction
At the CEN/TC 19/WG 24 meeting on 18 October, 2017 in Zurich, Switzerland there were technical
presentations describing serious vehicle fuel injection system wear and damage problems in Northern
Germany and the Southeast of the United Kingdom. A CEN task force was formed in January 2018 to
investigate these abrasive wear issues in order to establish the root cause and make recommendations.
After a year of investigations of market fuels, refinery product streams and field issues, the task force
produced a summary report detailing the findings of the fuel quality investigation and vehicle fuel
injection system damage caused by this contamination with respect to the work on European (diesel fuel)
standards. CEN/TC 19 requested to have this report published as a CEN/TR, parallel to implementing the
advice and recommendations in standardization and the market.
1 Scope
This document describes the investigation into diesel vehicle common rail fuel injection system damage
and excessive wear problems in a number of countries across Europe since 2014 carried out by
CEN/TC 19/WG 24 Abrasive Particles Task Force.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 590:2013+A1:2017, Automotive fuels - Diesel - Requirements and test methods
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
4 Symbols and abbreviations
For the purposes of this document, the following symbols and abbreviations apply.
ARA Antwerp Rotterdam Area
CONCAWE Conservation of Clean Air and Water in Europe
DFA Downstream Fuels Association
DLC Diamond Like Carbon
DMV Diesel Motor Vehicle
DPF Diesel Particulate Filter
EU European Union
FAME Fatty Acid Methyl Ester
FBT Filter Blocking Tendency
FIE Fuel Injection Equipment
HD Heavy Duty
HDEP Heavy Duty Engine Platform
ICP Inductive Coupled Plasma
ICP- AES Inductively coupled plasma-atomic emission spectrometry
ICP-MS Inductively coupled plasma-mass spectrometry
IPTV Incidents Per Thousand Vehicles
LD Light Duty
MDEG Medium Duty Engine Generation
M+H Mann and Hummel
MIS Months In Service
MS Mass spectrometer
MWV Mineralölwirtschaftsverband e.V.
NCV Needle Control Valve
NOK Not OK
OEM Original Equipment Manufacturer.
PKW Passenger Car
PRV Pressure Regulating Valve
Rail Fuel Rail
SEM Scanning Electron Microscope
Van Light Duty van
UKPIA UK Petroleum Industry Association
5 Description of fuel injection equipment problems
An increasing number of fuel injector warranty claims have been reported by a number of vehicle
manufacturers (Daimler, DAF, CNH Industrial, PSA and Volvo) and Fuel injection equipment
manufacturers (Bosch and Delphi). Both heavy duty and light duty vehicles are affected with modern high
pressure common rail diesel fuel injection systems of various vehicle configurations.
Investigation clearly shows internal damage to fuel injector moving parts, internal valves and pressure
relief valves causing internal injector leakage, engine malfunction indicator light illumination, engine
power loss, poor idle stability and in some cases complete engine shutdown.
PSA have reported the following vehicle field experience:
— 71 % of cases: on board light and engine power loss
— 21 % of cases: engine shut down during the driving
— 8 % of cases: idle instability
— vehicle minimum mileage: 4,451 km
— vehicle maximum mileage: 130,970 km
Only certain areas of Europe are affected with the highest numbers of vehicle incidents reported in
Northern Germany, the Southeast of the UK followed by Northern France and a small number in Spain.
See Figures 1 through 15 for the reports on the incidents. The vehicle manufacturers have reported a
small number of failures elsewhere in Europe but these are deemed as isolated incidents. Failures are
more common during the winter in the January/March timeframe (see Figure 7 and 10).
a) Claims by country
b) Claims in Germany only
Build year 2016, repair year 2017, status 08/2017
Key
a) Claims by country b) Claims in Germany only
A Germany A Bremen
B United Kingdom B Hamburg
C France C Braunschweig
D Netherlands D Hannover
E Poland E Rostock
F Czech Republic F Kiel
G Romania G Lübeck
H Spain H Magdeburg
I Belgium I Dresden
J Lithuania J Leipzig
K Slovak Republic K Single claims
L Single claims / no relationship
Figure 1 — Injector complaints inner leakage OM 47x (Courtesy Daimler)
a) Heavy duty engines
c) Personal vehicles
b) Vans
Figure 2 — Daimler reported incidents (Courtesy Daimler)
a) Inner leakage b) Inner leakage c) Inner leakage
nd st
1st half year 2017 2 half year 2017 1 quarter 2018
Figure 3 — Distribution of injector failures HDEP in Germany (Courtesy Daimler)

a) Inner leakage heavy duty b) Inner leakage middle
c) Inner leakage middle duty
engines 1st quarter 2018, duty engines 77% of all engines 80% of all claims,
Germany claims, Northern Germany South-East England
Figure 4 — Distribution of injector failures HDEP/MDEG (Courtesy Daimler)
b) Medium duty engines
a) Heavy duty engines
NOTE The claim rate in the marked areas is 13 times higher than in other parts of Great Britain.
Figure 5 — Injector claims “inner leakage” Great-Britain 2017/2018 (Courtesy Daimler)

a) Starry sky by repair date of inner leakage heavy duty engines Northern Germany

b) Starry sky by repair date of inner leakage heavy duty engines Southern Germany
Figure 6 — Starry sky by repair date of inner leakage heavy duty engines fuel injector claims
2017/2018 (Courtesy Daimler)
Key
A amount of registered issues B calendar week
Light blue line 2012 Dark blue line 2016
Orange line 2013 Green block 2017
Grey line 2014 Red block 2018
yellow line 2015
Figure 7 — Daimler heavy duty vehicle complaints (inner leakage) in Germany (Courtesy
Daimler)
Figure 8 illustrates the difference in injector failure rates between Northern and Southern Germany.

Key
Redish bars Northern Germany A Hamburg
Blueish bars Southern Germany B Bremen
C Rostock
D Frankfurt
E Stuttgart
Figure 8 — Injector failure rates HDEP in Germany (Courtesy Daimler)
DAF reported incidents are consistent with Daimler reported incidents in both Germany and the UK
(Figure 9). It should be noted that 78,7 % of the failures in Germany occurred in Northern Germany. Their
yearly trend since the start of the incidents is shown in Figure 11.

Figure 9 — DAF reported incidents (Courtesy DAF UK)
Figure 10 — Year comparison of failures per month for trucks over 16 ton (Courtesy DAF UK)
Figure 11 shows DAF (UK) comparative warranty rates for injectors and highlights the Southeast of the
UK area with the highest number of returns. Note that actual numbers are not reported for Figures 11
and 12 due to commercial confidentiality requirements.

Figure 11 — UK warranty information - Injectors (Courtesy DAF UK)
Figure 12 shows comparative warranty information for the Fuel Rail Pressure Regulating Valve (PRV)
and highlights that the highest number of failures are in the Southeast and East of England.

Figure 12 — UK warranty information – Rail and PRV (Courtesy DAF UK)
Reported incidents (2014-2017) by CNH Industrial are plotted in Figure 13 and these again are clustered
in Northern Germany (at least 25 % of claims are located in that area).

Figure 13 — CNH Industrial reported incidents on the German market (Courtesy CNH Industrial)
PSA reported incidents (Figure 14) are primarily in Northern Germany (41 %) and the UK (34 %) and to
a lesser extent in France (19 %) and Spain (6 %), with none in Italy. Overall 90% of the repair occurred
in February and March 2017, with fewer in May to July 2017.

Figure 14 — PSA reported incidents (Courtesy PSA)
Delphi reported incidents (Figure 15) are clustered in Northern Germany and the Southeast of the UK. It
is noted that a wide range of end users with issues had no obvious links. Also the issues in the areas
indicated became apparent mid-2014 and accelerated mid-2016. There is circumstantial evidence that
the affected areas predominantly see imported fuels.
Key
A Orange areas show primary locations, but not linked to single fleet, fuel outlet or storage location
B Yellow areas show also observed occasions of issues
Figure 15 — Particle contamination issues reported in Northern-Germany/Southern UK
(Courtesy Delphi)
Warranty information from Volvo UK, regarding FIE claims in London, Southeast and South coast of the
UK for the main engines used in Volvo trucks (D11, D13) show a significant increase in claims (FIE spare
part kits) starting late 2016, continuing into all 2017 and still at the same (higher) level in 2018.
6 Fuel injection system damage investigations
Investigations by Daimler, DAF, CNH, PSA, Delphi and Bosch show similar damage to fuel injector moving
parts, internal control valves and seats and pressure regulating valves. Figure 16 illustrates the internal
locations in the fuel injectors where damage has been recorded. Due to the very high pressures, the
working clearances between moving and sealing components in the fuel injection system are typically
1 – 4 µm, so only very small particles can pass between the moving parts and cause wear. Regardless of
injection equipment manufacture the solenoid valve seats and moving components show signs of serious
damage shown to be related to hard particulates < 4 µm in size.
NOTE On board vehicle filters are typically in the 4 – 5µm range and whilst they have some functionality below
4 microns they cannot protect against large numbers of < 1µm particles.
Key
A Intake filter
B Lower valve seat
C Upper valve seat
Figure 16 — Locations inside injectors affected by particle erosion (Courtesy Bosch)

Figure 17 shows the typical damage to solenoid valve seats caused by particle erosion and Figure 18
compares valve seat erosion from Northern Germany field failures with vehicle test components. Particle
wear from the field failures is comparable with vehicle test results.

Figure 17 — Failure HDEP injectors – particle erosion on body seat (Courtesy Daimler)

a) field DMV 25 b) field DMV 25 seat c) field DMV 25 seat
d) vehicle test DMV
needle beginning of beginning of beginning of
25 needle
channelling channelling channelling

e) DMV 25 needle f) DMV 25 seat h) vehicle test DMV
g) DMV 24 seat
significant significant channelling 24 seat
channelling channelling
Figure 18 — FIE particle erosion at valve seat and valve needle (Courtesy Bosch)
The damage is not just limited to valve seats as the sliding components locating the valves are also
affected as illustrated in Figures 19 and 20, where the severe erosion of light duty vehicle injector
components has been observed following low mileage in the UK and Germany. In Figure 19 the observed
rate of wear is many times higher than normally expected and there is clear evidence of particle erosion
which is not lubricity related. Similar erosion wear mechanism is observed across multiple vehicles.
Key
A New component B Maidstone (UK) D Wittenburg (Germany)
C Walton on Thames (UK) E Willemshaven (Germany)
Figure 19 — Severe erosion of light duty parts observed following low mileage in UK and
Germany (Courtesy Delphi Technologies)
The analysis of roughly 200 cases of returns on the parts indicated in Figure 20 told us that the majority
(180 cases) showed an NCV T3 change. Most cases came from Germany although they may be skewed by
sampling location. Incidents per 1 000 vehicles at twelve months in service (IPTV) had been low and quite
stable over time, but have dropped since the last quarter of 2015. There were no significant seasonal
patterns observed.
Key
a Erosion on seat in guide
b Erosion on valve head
Figure 20 — Particle robustness, light-duty field experience (Courtesy Daimler)
Figure 21 compares MDEG sliding pin wear from a 300 000 km vehicle operating correctly with that of
one removed from a vehicle with high leakage at 100 000 km. The damage to the surface can be seen
clearly.
Key
A Stem
B Collar
Figure 21 — MDEG sliding pin wear normal (top pin and green block) and failed (bottom and red
block) (Courtesy Daimler)
In Figure 22 wear patterns are compared between the field failure returns and test pins evaluated using
fuel artificially contaminated with so-called Arizona test dust. The wear patterns between the field failure
component and the test dust component are very similar in nature. The resulting loss of hydraulic
performance is also the same between field failure returned parts and the Arizona dust test.

Figure 22 — Comparable wear pattern on field returns (A) and Arizona dust verification
pattern (B) (Courtesy Daimler and Delphi)
Similar valve damage has been reported by CNH (Figure 23) and PSA (Figure 24).

Figure 23 — Injector failure on F1A engine - (Courtesy CNH Industrial)

Figure 24 — Examples of high wearing due to “abrasion” (Courtesy PSA)
Figure 25 shows wear damage from a failed injector in the Southeast of the UK consistent with that
reported by other manufacturers.
Figure 25 — Injector failure (Courtesy DAF (UK))
The damage to the valves, valve seats and sliding components in the fuel injectors increases internal
leakage within the fuel injector which affects its performance. Figure 26 shows the typical hydraulic
effects caused by particle erosion (injection quantity characteristics, Rail pressure 1 200 bar). This can
result in pressure boosting ahead of time, increased internal leakage causing retarded needle closing and
increased fuel throughout due to nozzle-widening by particle erosion.

Key
Black curve Injection quantity, undamaged valves
Red curve Injection quantity, seat/needle erosion at upper valve
Green curve Injection quantity, seat/needle erosion at upper and lower valve
① Lower valve, pressure boosting ahead of time caused by pressure influence via erosion channels
Upper valve, leakage results in quantity increased with the consequence of retarded valve closing
②
Nozzle, widening by particle erosion results in additional fuel throughput
③
Figure 26 — FIE particle erosion, hydraulic effects (Courtesy Bosch)
These hydraulic changes lead to the loss of the precise injector control required to deliver low diesel
vehicle emissions and good vehicle operability and ultimately can stop the vehicle.
Analysis by the fuel injection system manufacturers (Bosch and Delphi) summarized in this section of the
report, has identified particle erosion as the root cause of the fuel injection system damage. The particles
are shown to be hard and < 4 µm in size.
An official definition for hard and soft particles does not exist, however when considering their potential
to damage fuel injection components made of steel, particles as hard as steel or even harder can therefore
be classified as “hard” (reference value 300 HV30), particles with a lower hardness can be classified as
‘soft’.
7 Fuel quality investigations
Fuel filter analysis has been carried out on failed vehicles to investigate filter loading and contaminants:
a) Analysis carried out by M+H and Mahle;
b) Fuel filters from complaint vehicles from Northern and reference filters from Southern Germany;
c) Common characteristics:
i) High filter load for given runtime;
ii) Brown discolouration to fuel filter when compared to normal fuel filter grey colour from
Southern Germany (Figure 27);
iii) High share of metallic particles, see Figures 28 and 29 and Tables 1 and 2.

Figure 27 — Fuel filter HDEP of complaint vehicle from Northern Germany (left) and a typical
version from Southern Germany (right) (Courtesy Daimler)
Key
Blue bars Northern Germany, 40 000 km mileage
Red bars Southern Germany, 120 000 km mileage
Green bars Norther Germany, 108 000 km mileage
A concentration (mg/m ) H sodium O nickel
B aluminium I potassium P lead
C copper J silicon Q phosphorus
D iron K zinc R sulphur
E calcium L chrome S silver
F magnesium M manganese T tin
G boron N molybdenum
Figure 28 — HDEP Befund filter analysis of metals (Courtesy Daimler)
Key
Blue bars Northern Germany, 40 000 km mileage
Red bars Southern Germany, 120 000 km mileage
Green bars Northern Germany, 108 000 km mileage
A concentration (µg/m ) C nitrate
B chloride D sulfate
Figure 29 — HDEP Befund filter inorganic content analysis (Courtesy Daimler)
Table 1 — EOX-material identification of dirt from a MDEG fuel filter module after 94 228 km
(Courtesy Daimler)
Spectrum C O Mg Si Ca Fe Cu Sum

1 56 38 3 3 100
2 54 39 1 3 4 100
3 56 41 3 100
4 55 42 3 100
5 54 39 3 4 100
Table 2 — Particle count per particle size from a MDEG fuel filter module (Courtesy Daimler)
Class Sum particles ≤ 5,00
Length Width
UL-Steel 763 1068
Silicate (general) 273 392
Aluminium 96 132
Silicate (CaCO3) 38 75
NL-Steel 34 43
Silicate (SiO2) 26 39
PTFE 18 34
Salts (Chloride) 16 23
Al-Alloy (Si) 5 8
CR-Steel 4 19
Iron oxide 4 7
Other phosphates 4 5
Zinc 4 4
Al-Alloy (Mg) 3 4
Zinc/iron 3 4
Organic material 3 3
Aluminium oxide 2 3
TiO2 2 5
Mg-Silicate 1 2
Copper 1 2
Ba-Sulphate 1 2
Iron/phosphor 1 1
Zinc/phosphate 0 1
Messing 0 1
Ca-phosphate 0 2
Sum of counted area 1 302 1 870
(33,4 %)
Very high concentrations of ferrous particles measured in fuels from affected vehicles (Figure 30).

Key
A percentage N alloy Si > 5
B steel O alloy < 5
C steel rich P mineral Si-Al-O
D low alloy Q zinc
E high alloy R Si-Mg-(Al)-O
F mineral S Zn-Cr
G mineral Si-Al-Ko-O T SiO2
H metal U others
I fibre V vehicle A
J salts W vehicle B
K lime X vehicle C
L Si/Si-C/Si-N Y vehicle D
M lube additive Z vehicle E
Figure 30 — Heavy duty vehicle filters analysed at multiple laboratories (Courtesy Delphi)
A similar metallic debris composition is observed across the affected vehicles. The task force considered
the possibility that the hard particles could come from internal wear of the Diamond-Like Carbon (DLC)
coatings in the FIE. This possibility was discounted by the FIE manufacturers because:
— The total volume of DLC coatings is exceptionally small.
— DLC normally wears to form graphite.
— The DLC coating is not always damaged.
The fuel injection equipment manufacturers have confirmed that the large amount of particles found in
the fuel and the fuel filters have not come from internal wear in the fuel injection equipment but from an
external source.
Vehicle fuel filter analysis conducted by Daimler comparing service filters from non-affected vehicles
from Southern Germany with failed vehicles from Northern Germany (Figures 31 −33) clearly show a
very high proportion of iron in the Northern Germany filters (67 % - 87 %, Figure 32) when compared to
Southern Germany (4 % - 14 %, Figure 31).
The failed vehicles from Northern Germany had covered mileages from 84,041 to 120,340 km and the
non-affected vehicles from Southern Germany had covered mileages from 139,645 to 143,502 km.

Figure 31 — Filter particle analysis – service filter (1,0 – 10,0) µm (Courtesy Daimler)

Figure 32 — Filter particle analysis – inner leakage filter (1,0 – 10,0) µm (Courtesy Daimler)
Key
A particle count D ferrous particles
B service filter, Nürnberg, 141 297 km E other minerals
C inner leakage filter, Bremen, 84 041 km
Figure 33 — Filter particle analysis comparison –filter (1,0 – 10,0) µm (Courtesy Daimler)
Analysis of failed vehicle fuel filters and samples from the fuel tanks by CNH Industrial shows evidence
of silicon dioxide (Figures 23 and 34).
Proprietary analysis of fuel injector debris carried out by Delphi (Figure 35) shows evidence of high levels
of silicon with incidental also iron although not necessarily at the same time.

NOTE External contamination of siliciumdioxide found on filter; particle size varies from 0,06 mm to 0,19 mm
Figure 34 — Analysis of failed filters from fuel tanks (Courtesy CNH Industrial)
Key
A element analysed E raster scan of filter, highlighting is silicon
B % mass F Maidstone, UK
C Walton on Thames, UK G Wittenburg, Germany
D Wilhelmshaven, Germany
Figure 35 — Analysis of fuel injector debris (Courtesy Delphi)
Analysis of failed vehicle fuel samples from the UK by PSA is shown in Figure 36. A high level of silicon
was noted but it was not possible to determine the iron content due to the proprietary PSA on board fuel
DPF catalyst additive being present in the fuel.

Figure 36 — Analysis of failed vehicle fuel samples from the UK (Courtesy PSA)
Particulate counting measurements have been made by a number of companies using a range of particle
counting test methods such as ASTM D7619 [1], ASTM D7647 [2] and IP 565 [3].
The ASTM D7619 particle counting test scope notes that it is also suitable for light and middle distillate
fuel, and bio fuels such as biodiesel and biodiesel blends, in the overall range from 4 μm(c) to 100 μm(c)
and in the size bands ≥ 4 μm(c), ≥ 6 μm(c), and ≥ 14 μm(c). ASTM D7619 will detect water droplets and
it is possible to include a drying step to remove the water so only dirt and other contaminating debris are
counted. ASTM D7619 counts both hard and soft particles.
Figure 37 shows particle counts measured in the UK in fuel samples from failed vehicle fuel tanks. The
content of the fuel tank represents the quality of the last fuel fill together with any accumulated debris
over time. It is a useful indicator of current fuel quality but may not be representative of the fuel
consumed over a longer period of time. Particle counting was performed according to the ASTM D7647.

Figure 37 — Average particle count per region in the UK (Courtesy DAF UK)
Figure 38 compares the regional particle count by ASTM D7647 with iron content measured by ICP. It
should be noted that the ICP test analysis primarily focuses on dissolved material and so sample
preparation needs to be considered carefully. Dissolved metals do not contribute to abrasive fuel system
wear so it is recommended that these data should be interpreted with caution. It is not clear if the method
will be fully sensitive to undissolved particle contamination and particles could affect the overall test
results. If sample preparation has included a metal digestion step then the dissolved metal measurements
could indicate the presence of metal particles in the fuel.

Figure 38 — Particle count (left axis) in comparison to iron content (right axis) in different
regions (Courtesy DAF UK)
Figure 39 compares particle count by region with silicon content in fuel samples from failed vehicle fuel
tanks. The fuel samples were taken in workshops by mechanics repairing the vehicles and the cleanliness
of the sample taking process cannot be guaranteed.
Figure 39 — Particle count (left axis) in comparison to silicon content (right axis) in different
regions (Courtesy DAF (UK))
Fuel quality survey data from the UK (Figure 40) shows that the particle count increased in 2013 just
prior to the onset of vehicle injection system damage failures in 2014. Most high particle fuels are
observed in south east UK. Particle counts here are more typical for developing markets and correspond
to location and timing of abrasion issues. These high particle counts were not observed in Germany,
though there were limited data available from North Germany.

Key
A France D issues typically apparent after 12 months in service
B Germany E erosion issues first noted 2014
C United Kingdom
Figure 40 — Fuel quality survey data on particle count from the UK (based on data from SGS
Global Fuel Survey, courtesy Delphi and SGS)
The same fuel survey data shows that dissolved iron contents increased from 2013. Also 27 % of UK fuels
iron contents exceed 0,1 mg/kg (100 µg/kg) compared to 3 % for the rest of the EU (Figure 41). It is noted
that dissolved iron will not cause erosion, but indicates that erosive particles are also likely to be iron. So,
both increasing particle count and iron content in UK fuels correlate with the present issue.

Key
A United Kingdom
B issues typically apparent after 12 months in service
C erosion issues first noted 2014
Figure 41 — Fuel quality survey data on particle count from the UK showing high dissolved iron
(based on data from SGS Global Fuel Survey, courtesy Delphi and SGS)
Fuel particle survey data provided by the BSI Cold Filter Blocking Task Force using the IP565 particle
counting test method (essentially the same as ASTM D7619 although not validated on diesel) also shows
an increase in particulate levels in the affected regions (Southeast and East of England) in the 2014/15
timeframe (Figure 42). It should be noted that these tests were carried out without the sample drying
step previously discussed although subsequent tests show that most fuel samples had similar particulate
contents.
Key
A ≥ 4 micron particles / ml (IP 565) G Scotland
B East Midlands H South East
C East of England I South West
D London J Wales
E North East K West Midlands
F North West L Yorkshire and Humberside
Figure 42 — ≥ 4 µm particle count per UK region, winter 2014/2015 (Courtesy BSI)
The particulate levels returned to normal in the 2015/16 time frame (Figure 43) but then increased
significantly in the 2016/17 survey as illustrated by Figure 44. There were three main areas affected, the
Southeast, East and Northeast of England. Vehicle fuel injection system damage was initially only
reported in the Southeast and East of England. Subsequently further analysis of vehicle failures in the UK
has highlighted the Northeast as an area with a higher level of failures (approximately 13 times see
Figure 5) when compared to non-affected regions.
Key
A ≥ 4 micron particles / ml (IP 565) G Scotland
B East Midlands H South East
C East of England I South West
D London J Wales
E North East K West Midlands
F North West L Yorkshire and Humberside
Figure 43 — ≥ 4 µm particle count per UK region, winter 2015/2016 (Courtesy BSI)
Key
A ≥ 4 micron particles / ml (IP 565) H Scotland
B East Midlands I South East
C East of England J South West
D London K Wales
E North East L West Midlands
F North West M Yorkshire and Humberside
G Northern Ireland
Figure 44 — ≥ 4 µm particle count per UK region, winter 2016/2017 (Courtesy BSI)
High levels of particles could also be due to the presence of FAME. Particles present in FAME are likely to
be organic and soft in nature and unlikely to cause damage to fuel injection equipment but will contribute
to filter plugging over time.
More recent data received from BSI for Winter 2017/18 (Figure 45) shows a reduction in particle counts
from UK service stations. The highest particle counts are in the Northeast of the UK but overall levels are
much lower than previously recorded although a number of samples had ≥ 4 µm particle counts > 5 000
but < 10 000.
Key
A ≥ 4 micron particles/ml (IP 565) E Region winter 2017 (left) and 2018 (right)
B South East
C East of England
D North East
Figure 45 — ≥ 4 µm particle count per UK region, winter 2017/2018 (Courtesy BSI)
A number of retail service station quality checks have been made and reported to the task force.
A Delphi survey from the UK (Figure 46) shows that major fuel supplier brands are affected in the UK,
with high particulate counts above that recommended by the automobile industry World Wide Fuel
Charter (WWFC) [4] fuel quality guidance document (18/16/13 per ISO 4406 [6]) and ASTM D975
appendix 8 [5].
The WWFC was developed by the vehicle manufacturers and first established in 1998 to increase
understanding of the fuel quality needs of motor vehicle and engine technologies and to promote fuel
quality harmonization worldwide in accordance with those needs. Importantly, the Charter matches fuel
specifications to the vehicle and engine specifications required to meet various customer needs around
the world.
ISO 4406 [6] gives no ranking or advice on the quality of a fuel, however it is a widely used classification
system from the hydraulic industry.
Key
green "Relatively cleaner" (≤ 18/16/13)
yellow Borderline (19/17/14 to 20/18/16)
red "Relatively dirtier" (≥ 21/19/17)
Figure 46 — Major brand fuels affected in Southeast UK (based on data from SGS Global Fuel
Survey, courtesy Delphi and SGS)
The Downstream Fuels Association (DFA) from the UK provided data on samples collected from retail
sites around the UK (Figures 47, 48, 49 and 50):
— Approximately 200 samples taken throughout the year
— Range of different brands included
— Tested for a range of properties including metals by ICP
— Data presented annually from 2014 arranged by region
55 samples with Si content > 0,5 mg/kg (500 µg/kg)
— Around half in Yorkshire / Humberside region
— Six samples > 1,0 mg/kg (1 000 µg/kg)
— Two in Scotland, one each in Wales, South West, East Anglia and Yorkshire
— Max value 2,6 mg/kg (2 600 µg/kg) in a sample from Scotland in 2015
— Mean value 0,17 mg/kg (170 µg/kg)
15 samples with Fe content > 0,2 mg/kg (200 µg/kg)
— 11 of these in 2017
— Max value 0,8 mg/kg (800 µg/kg) in two samples, one from Scotland and one from Wales taken
in 2017
— Mean value 0,04 mg/kg (40 µg/kg)

Figure 47 — Silicon and iron results from samples taken in 2014 in the UK (Courtesy DFA)
Figure 48 — Silicon and iron results from samples taken in 2015 in the UK (Courtesy DFA)

Figure 49 — Silicon and iron results from samples taken in 2016 in the UK (Courtesy DFA)
Figure 50 — Silicon and iron results from samples taken in 2017 in the UK (Courtesy DFA)
Concawe, the oil industry association has also conducted a number of pan-European retail service station
fuel quality surveys measuring metals contents.
The fuel samples evaluated were taken from service stations in European countries.
The countries selected for this survey represent a significant fraction of the total European fuel
consumption. The distribution of fuel sampling locations within each country was selected with
sensitivity to various issues, including:
— Regions in the country where bio-components are most likely to be in use
— Supply and distribution logistics
— The numbers of samples were chosen to reflect the overall market for fuel grades of the particular
country and of Europe as a whole.
— The Concawe samples were subjected to a solvation step to ensure any metal particles were dissolved
prior to measurement.
As a result the majority of the samples were regular grades rather than premium grades reflecting the
market for these grades.
Figure 51 shows detailed information on the numbers of samples collected over the period of time in the
different countries.
Figure 51 — Market fuel surveys 2008 - 2016 (Courtesy Concawe)
Key
A average metal content (µg/kg) B country
C Finland M sodium
D France N magnesium
E Germany O chromium
F Italy P iron
G Netherlands Q zinc
H Poland R copper
I Sweden
J Spain
K United Kingdom
L EU
Figure 52 — Diesel fuels metal content in 2008 (Courtesy Concawe)

Figure 53 — Diesel fuels metal average content (µg/kg) in 2008 and 2010 (Courtesy Concawe)
Figure 54 — Diesel fuels metal content(µg/kg) in 2015 (Courtesy Concawe)
The Concawe surveys indicate that average iron contents are typically < 40 µg/kg and average silicon
contents can be as high as 600 µg/kg but are more usually < 5µg/kg. The high silicon results recorded in
2010 are thought to be due to interference by the diesel anti-foam additive which contains silicon. The
CONCAWE iron and silicon results are much lower than that reported earlier in the report by DAF
(Figures 40 and 41) although the DAF samples are from vehicle fuel tanks where there could be a
concentration effect.
Care should be taken when comparing the metals test results as different test methods have been used,
with the DFA data not being determined below 100 µg/kg (see ASTM D7111 [7]) whereas Concawe used
a more accurate ICP-MS test method.
Inductively coupled plasma (ICP) analytical techniques provide details of the elements contained within
a sample. It is used to determine trace levels of metals and other elements of interest in a sample of test
material. Samples must be able to be solvated. Its main advantage over alternative techniques is the low
level of background readings from the instrument itself. It should be noted that the ICP test analysis
primarily focuses on dissolved material. As mentioned previously in this report, dissolved metals do not
contribute to abrasive fuel system wear so it is recommended that sample preparation should be taken
into account when interpreting these data.
The ICP source in the ICP-MS technique fragments chemicals in a different way to other MS techniques.
It is suitable for the ultra-trace analysis of metal elements in the ppb ranges, and a limited number of non-
metallic elements (e.g. S, P). The technique is sensitive to the method of sample preparation.
The Concawe data was sampled over three separate years across Europe in a very well controlled test
programme in order to determine normal dissolved metals contents in diesel fuel and is therefore a useful
benchmark for comparison.
The United Kingdom Petroleum Industry Association (UKPIA) has provided particle count data on diesel
and gasoil produced during 2017 (Figure 55). These data indicate that typical UK refinery
production ≥ 4 µm particle counts do not exceed 6 582 and the mean level is 1 851. These low particulate
counts are not surprising as diesel fuel manufacture is a distillation process so the opportunity for
particulate contamination during production i
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