EFFECT OF AN ETHANOL-DIESEL BLEND ON THE SURFACE ROUGHNESS OF WORK ELEMENTS OF A COMMON RAIL INJECTION PUMP
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MEMORIAS DEL XVI CONGRESO INTERNACIONAL ANUAL DE LA SOMIM
22 al 24 DE SEPTIEMBRE, 2010 MONTERREY, NUEVO LEÓN, MÉXICO
EFFECT OF AN ETHANOL-DIESEL BLEND ON THE SURFACE
ROUGHNESS OF WORK ELEMENTS OF A COMMON RAIL INJECTION
PUMP
1
Simón Martínez-Martínez, 2Octavio Armas-Vergel, 2Carmen Mata-Montes.
1
Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León
Pedro de Alba s/n, Apdo. Postal 076 Suc. F, CP 66450, San Nicolás de los Garza, N.L., México
Tel.: +52 (81) 832 940 20 Fax: +52 (81) 833 209 04
2
Departamento de Mecánica Aplicada e Ingeniaría de Proyectos, Universidad de Castilla-La Mancha
Avd. Camilo José Cela s/n. Apdo Postal 13071, Ciudad Real, España
Tel.: +34 926 29 53 00 Fax: +34-926-295361
simon.martinez@uanl.edu.mx, octavio.armas@uclm.es, mariacarmen.mata@uclm.es
elementos de la bomba sometidos a un trabajo
RESUMEN
severo.
Este trabajo presenta un estudio comparativo
experimental, para determinar el desgaste en un ABSTRACT
sistema de inyección common rail empleado
The present work has been focused on the
habitualmente en vehículos ligeros diesel,
comparative experimental study for determining
usando diesel convencional y una mezcla de
the wear in a model of a common rail injection
etanol con diesel al 7.7.% (v/v). Para la
system used in light duty diesel vehicles. Two
realización del estudio se dispuso de dos
Bosch fuel injection systems, each composed by
sistemas de inyección Bosch compuestos, cada
a high pressure injection pump Bosch (270
uno de ellos, por una bomba de alta presión
CDI), the common rail and a Bosch
Bosch (270 CDI), un common rail y un inyector
piezoelectric fuel injector, were selected for to
piezoeléctrico Bosch. El primero de los sistemas
be tested with two fuels. The first of the systems
se utilizó en los ensayos con diesel
was tested with a low sulphur commercial diesel
convencional de bajo contenido en azufre,
fuel while the second was tested with an
mientras que el segundo fue ensayado
ethanol-diesel blend (7.7 % v/v). Both systems
empleando una mezcla etanol con diesel al 7.7%
were tested during an accelerated durability test.
v/v de etanol. Ambos sistemas se ensayaron
In both cases the injection systems were
durante un test acelerado de durabilidad. Para
mounted in an injection test bench and were
realizar estos experimentos, los sistemas fueron
working during 12 hours/day during 600 hours.
instalados en un banco de bombas, donde
An injection pressure of 1500 bar, a regime of
estuvieron trabajando 12 horas/día hasta
2500 min-1 and an injection time of 1 ms were
completar un total de 600 horas. Los parámetros
selected as the most critical engine operating
de trabajo establecidos fueron 1500 bar de
conditions. The selected test conditions were
presión de inyección, régimen de giro de 2500
equivalent to the conduction of a light duty
min-1 y un tiempo de inyección de 1 ms, siendo
vehicle during more than 120000 km. Before
estas condiciones de operación las más críticas
and after the durability tests with each fuel
posibles. Estas condiciones de ensayo equivalen
tested, the surface roughness of several elements
a recorrer más de 120000 km con el vehículo.
of the injection pump was determined by means
Antes y después de los ensayos de durabilidad
of a tester for the roughness surface
con cada combustible, se realizaron medidas
characterization. The most important conclusion
usando un medidor de rugosidad superficial de
derived from the work has been that the use of
los elementos más importantes de la bomba para
an ethanol-diesel blend (7.7 % v/v) produced a
valorar el efecto de los combustibles sobre la
similar effect on the roughness surface of the
microestructura superficial de los elementos
injection pump elements as that produced by the
estudiados. La conclusión más importante
diesel fuel used during the same test conditions.
derivada este trabajo es que el uso de la mezcla
etanol-diesel (7.7% v/v) produce un efecto
similar al que produce el diesel convencional NOMENCLATURA
sobre la rugosidad de las superficies de los Ra - Arithmetic mean roughness value
Rz - Mean peak to valley height
ISBN: 978-607-95309-3-8
Derechos Reservados © 2010, SOMIMMEMORIAS DEL XVI CONGRESO INTERNACIONAL ANUAL DE LA SOMIM
22 al 24 DE SEPTIEMBRE, 2010 MONTERREY, NUEVO LEÓN, MÉXICO
1. INTRODUCTION The durability test of the injection system was
carried out on an injection test bench model
In the last three decades the increase in
Asia DieselTM. The injection test bench
environmental pollution caused by internal
reproduced all the conditions during the study
combustion engines has become a serious social
with each fuel tested. The test conditions are
problem, coupled with this, high consumption
shown in table 2.
of fossil fuels and near exhaustion has elevated
the use of alternative fuels in engines in recent Table 2 Test conditions
years. Multiple researches on the behaviour Parameter Value
injection diesel [1-3], which have allowed to Rotation speed 2500 min-1
have a better understanding of the phenomenon Injection pressure 1500 bar
and therefore has been possible to optimize the Injection time 1 ms
combustion process to some extent. Recent Fuel temperature 40 ºC
Operation time 10-12 hours/day
studies which have analyzed mixtures of diesel- Total test time 600 hours
ethanol [4, 5] show that it is possible to raise the
performance of the engine, since the use of To prevent the ethanol evaporation to the
ethanol in the diesel improves combustion for atmosphere and to remain the water content in
the liberation of oxygen that ethanol produces the range established by the European fuel
during oxidation, also [6, 7, 9, 10] reported quality standard EN-590, the hydraulic block
significant improvements in reducing pollutant diagram of the injection test bench was
emissions. On the basis of these premises, found modified. The original fuel tank of the injection
it interesting to study the effects of ethanol on test bench was changed by a hermetical tank. To
wear on the elements of the injection system. prevent the pressure variation inside the fuel
All liquid hydrocarbons used in engines as tank a pressure and/or vacuum security valve
petrol, diesel, among others, require contain was installed. Before and after the durability test
certain lubricity to protect surfaces in contact of the total fuel delivery was determined using
the pumps, injectors, valves and any mobile diesel fuel. The test conditions for fuel delivery
system through which fuel flow. This work determination were those presented in table 2.
demonstrates the feasibility of using mixtures
To determine the effect of the durability test on
diesel-ethanol in high pressure injection systems
the elements surface a HOMMEL WERKE®
mainly analyzing deterioration which may give
T500 roughness tester was used. The elements
rise to a fuel with low of lubricity properties
used for the roughness surface analysis were the
such as ethanol.
drive shaft; the flange and the cam (see Figure
1).
2. EXPERIMENTAL SET-UP
The injection system used for this study has
been composed by a Bosch high pressure
injection pump from first generation with
pistons. This pump is employed connected to a
common rail and that to four injectors
electronically controlled. This model of the
injection system is installed in the most of diesel
engines used in several models of the Mercedes
Benz light duty vehicles and also is similar to
those used by the most of European diesel Figure 1 Elements of the injection pump analyzed before
and after the durability test. 1) flange, 2) drive shaft, 3) cam
engines with around 2 liters of the cylinder
displacement. Table 1 shows the main
characteristics of the injection system tested in FUEL TESTED
this study. A low sulphur diesel fuel was used as a
Table 1 Main characteristics of the injection system tested reference for comparison (Diesel). A blend was
Characteristics made with 7.7 % v/v ethanol (E) and reference
Injection pump Bosch, with pistons, first diesel fuel, using a stabilizing additive (0.62 %
generation v/v), and it was denoted as e-diesel fuel (E-
Common rail for 4 Model 270 CDI Mercedes
injectors Benz
Diesel). The additive and the ethanol were
Pump-common rail line 400 mm supplied by Abengoa Bioenergy and O2 Diesel
length companies. The ethanol volume content of the
Common rail-injector 150 mm tested blend was determined attending to the
line length results of the previous study [7, 8, 11-13]. The
Common rail length 550 mm
main properties, either measured or calculated,
Line internal diameter 2 mm
of the tested fuels are presented in Table 3.
ISBN: 978-607-95309-3-8
Derechos Reservados © 2010, SOMIMMEMORIAS DEL XVI CONGRESO INTERNACIONAL ANUAL DE LA SOMIM
22 al 24 DE SEPTIEMBRE, 2010 MONTERREY, NUEVO LEÓN, MÉXICO
Since the additive composition was not known, independently of the fuel used. However, in
all the characteristics of the E-diesel fuel point P3 a decrease of both Ra and Rz
derived from the composition were determined parameters was observed when e-diesel blend
using pure diesel and ethanol fuels. was used. The reduction of Ra and Rz in this
Table 3. Fuel properties
zone of the shaft can be explained by the lower
lubricity of the blend (See Table 3).
Parameter Diesel E-Diesel E
Density at 15 ºC
834,9 831 792
(kg/m3)
Kinematic viscosity at
2.72 2.408 1.13
40 ºC (cSt)
Lubricity
(µm corrected wear 315 327 842
scar at 60ºC)c
Cold filter plug point
-19 -18MEMORIAS DEL XVI CONGRESO INTERNACIONAL ANUAL DE LA SOMIM
22 al 24 DE SEPTIEMBRE, 2010 MONTERREY, NUEVO LEÓN, MÉXICO
1 8
2
SHAFT
∆ Ra (µm)
∆ Rz (µm)
0.5 0
SHAFT
0 -2
-2
-4
P1 P2 P3 P1 P2 P3
Diesel E-diesel
Figure 5 ∆Ra and ∆Rz obtained from the shaft surface and each fuel tested.
Figure 5 shows the maximum values of ∆Ra and Figures 6 and 7 show the Ra and Rz parameters
∆Rz were obtained from each point and shaft. of the cams and the flanges used with both fuels
These differences were obtained between the before and after the durability test.
initial and final mean values of the Ra and Rz
According to the Ra and Rz values and their
parameters respectively. The highest values of
confidence intervals obtained from both
∆Ra and ∆Rz were obtained when e-diesel was
elements, can be affirmed that the effect of fuel
used. These results show a slightly higher wear
is practically negligible in three points tested.
produced by the e-diesel blend on the zone
where is located point P3. This behavior can be
explained by the lower lubricity of the e-diesel
blend such as the Table 3 shows.
2.5 25
2 20 CAM
Ra (µm)
Rz (µm)
CAM 2.4
0.2
1.6
0.1
0.8
0 0
P1 P2 P3 P1 P2 P3
0h Diesel 600h Diesel 0h E-diesel 600h E-diesel
Figure 6 Ra and Rz parameters obtained from the cam surface.
2.5 25
FLANGE
2 20 FLANGE
Ra (µm)
Rz (µm)
1.5 15
1 10
0.5 5
0 0
P1 P2 P3 P1 P2 P3
0h Diesel 600h Diesel 0h E-diesel 600h E-diesel
Figure 7 Ra and Rz parameters obtained from the internal flange surface
analyzed. The main conclusions are summarized
CONCLUSIONS
as follows:
Compared to diesel fuel, the effects of a 7.7 %
1. The surface roughness obtained from the
ethanol-diesel blend on a model and make of
cam, flange and drive shaft have been analyzed
injection system after a durability test have been
by means of two parameters, Ra and Rz. The
three points tested for the cam and the flange
ISBN: 978-607-95309-3-8
Derechos Reservados © 2010, SOMIMMEMORIAS DEL XVI CONGRESO INTERNACIONAL ANUAL DE LA SOMIM
22 al 24 DE SEPTIEMBRE, 2010 MONTERREY, NUEVO LEÓN, MÉXICO
showed a negligible effect of fuels as well in engine fuelled with ethanol–diesel blends”
points P1 and P2 of the drive shaft. However, at Applied Thermal Engineering, 2009.
point P3 of the drive shaft, a decrease of Ra and
[6] M. Bahattin Celik “Experimental
Rz parameters was detected when the ethanol-
determination of suitable ethanol–gasoline
diesel blend was used. The zone around point
blend rate at high compression ratio for gasoline
P3 is the most charged during the drive shaft
engine” Applied Thermal Engineering, 2008.
operation and the reduction of Ra and Rz can be
explained by the slightly lower lubricity of the [7] Lapuerta, M.; García-Contreras, R.;
blend. Agudelo, J.R. Lubricity of Ethanol-Biodiesel-
Diesel Fuel Blends. Energy Fuels,
2. The results of the durability test showed that
DOI:10.102/ef901082k, 2009.
the effect on the wear produced by the e-diesel
fuel on the main parts of the high pressure pump [8] Lapuerta, M.; Armas, O.; Garcia-Contreras,
of the common rail injection system studied was R. Effect of ethanol on blending stability and
similar that produced by the diesel fuel after 600 diesel engine emissions. Energy and Fuel, Vol.
h of operation in severe controlled conditions. 23, 4343-4354, 2009.
[9] Lapuerta, M.; Armas, O.; García-Contreras,
ACKNOWLEDGEMENTS
R. Stability of diesel–bioethanol blends for use
The authors are grateful for the financial support in diesel engines. Fuel, Vol. 86, Issue:10-11,
provided by: a) Abengoa Bioenergy New 1351-1357, 2007.
Technologies S.A. (project CENIT, IDEA
[10] Lapuerta, M., Armas, O., Herreros, J.M.
program), b) the UCLM, the Mexican federal
Emissions from a diesel-bioethanol blend in an
government through the research net “Fuentes
automotive diesel engine. Fuel, Vol. 87, Issue:
Renovables y Uso Eficiente de la Energía”
1, 25-31, 2008.
(SEP-PROMEP) and CONACyT through
project number: 103334, to Prof. Simón [11] P. Arkoudeas, F. Zannikos, E. Lois “The
Martínez-Martínez for his stays in this tribological behavior of essential oils in low
university and c) the Castilla La Mancha sulphur automotive diesel” Energy Fuels, 2008.
government to Eng. María Carmen Mata
Montes through the project COMEDIA PAI [12] R.L. McCormick, M. Ratcliff, L. Moens, R.
060-160 and d) the technical support provided Lawrence “Several factors affecting the stability
by Turbo inyección Alonso S.A. of biodiesel in standard accelerated tests” Fuels
Processing Technology, 2007.
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ISBN: 978-607-95309-3-8
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