Field of the invention
[0001] The present invention relates to motor-vehicle internal combustion engines with a
cooling system, of the type indicated in the preamble of claim 1.
[0002] The expressions "high-pressure EGR circuit" and "low-pressure EGR circuit" are used
in the present description and in the claims that follow with reference to circuits
known per se, which are used in internal combustion engines, and in particular in
turbocharged diesel engines, in order to recirculate part of the flow of exhaust gases
leaving the engine back into the combustion chambers of the engine cylinders. According
to the most conventional technique, recirculation of exhaust gases is achieved by
means of a high-pressure
exhaust gas recirculation (EGR) circuit, which provides a direct connection between the outlet of the exhaust
manifold of the engine and the inlet of the intake manifold of the engine. Along this
connection, an EGR valve is provided, which is controlled to regulate the portion
of the flow of exhaust gases leaving the exhaust manifold of the engine, to be recirculated
into the intake manifold of the engine, along a portion of the intake duct downstream
of the supercharging compressor, i.e. in an environment at a relatively high pressure
(from which the expression "high-pressure EGR" derives). A heat exchanger is interposed
in the high-pressure EGR circuit, for cooling the recirculated exhaust gases. According
to an additional known technique, an internal combustion engine, in particular a turbocharged
diesel engine, can also be provided with a low-pressure EGR circuit, which includes
an exhaust gas recirculation duct that starts from the exhaust line of the engine,
at a section thereof downstream of the exhaust gas treatment devices, and which brings
the recirculated exhaust gases into the engine intake duct, upstream of the supercharging
compressor (from which the expression "low-pressure EGR" derives). A heat exchanger
is also interposed in the low-pressure EGR circuit, for cooling the recirculated exhaust
gases.
Technical problem
[0003] The configuration of the engine cooling system varies widely depending on the designer's
choices, which, in turn, are a function of the motor-vehicle class on which the engine
is mounted and of the power of the engine. In simpler solutions, usually only a high-pressure
EGR circuit used, while in high-class vehicles both a high-pressure EGR circuit and
a low-pressure EGR circuit are preferably adopted.
[0004] Each selected engine configuration involves a specific design of the cooling system
and a specific arrangement of its components and their connections. Consequently,
modifying an engine cooling system to provide one or more additional components which
were not originally provided for that engine, such as a low-pressure EGR circuit cooler,
is usually a complicated and expensive task.
[0005] However, an object of the invention is to provide a cooling system that is easily
adaptable and that does not require major changes when it comes to passing from a
simpler configuration to a more complex configuration of the engine and the various
auxiliary systems associated therewith.
Summary of the invention
[0007] In view of achieving the aforesaid objects, the present invention provides an engine
as set forth in claim 1.
Advantages and additional features of the invention
[0008] The main advantage of the above-described structure and arrangement lies in that
if a low-pressure EGR circuit is added in an engine originally designed without this
component, it is not necessary to radically modify the configuration of the cooling
system, because it is not necessary to modify the line for the fluid leaving the engine,
for the purpose of causing the cooling fluid leaving the engine to go through anhigh-pressure
EGR cooler and a low-pressure EGR cooler arranged in series. In the invention, the
low-pressure EGR cooler is traversed by the aforesaid auxiliary line, which is an
easily-integrated component in the system, without any need of a substantial modification
to the configuration and arrangement of the line for the cooling fluid leaving the
engine.
[0009] With respect to a conventional solution in which the cooling fluid leaving the engine
flows through a high-pressure EGR cooler and a low-pressure EGR cooler arranged in
series, a further advantage of the internal combustion engine of the invention lies
in that the fluid that follows through the low-pressure EGR cooler is fluid coming
from the radiator, which is therefore at a relatively lower temperature (e.g. about
82°C) than that of the fluid leaving the high-pressure EGR cooler (about 90°C). The
low-pressure EGR cooler is therefore more efficient.
[0010] According to a preferred embodiment, the aforesaid auxiliary pump is a pump driven
by an electric motor. The electric motor driving the auxiliary pump is controlled
by an electronic control unit, which is programmed to control the activation of the
auxiliary pump as a function of the engine operating conditions, and as a function
of a series of predetermined parameters, in particular as a function of the activation
of the low-pressure EGR circuit and, for example, as a function of temperature values
detected by one or more temperature sensors associated with the EGR circuits of the
engine.
[0011] Preferably, the electric motor of the auxiliary pump is controlled (for example in
a pulse width modulation (PWM) mode, by modulating its duty cycle) as a function of
the climatic conditions and/or parameters relating to harmful exhaust emissions.
[0012] In an additional embodiment, the cooling system also comprises an additional line
that starts from said auxiliary line, downstream of the aforesaid auxiliary pump and
passing through a cooler for an urea solution injector forming part of a catalytic
regeneration system, said additional line ending in an urea solution tank associated
with said engine.
[0013] As can be seen, therefore, the additional circuit forming part of the cooling system
of the internal combustion engine according to the invention can also be advantageously
used to obtain a cooling function of auxiliary components which the engine can be
provided with. Again, this result is achieved without any significant modification
to the entire engine cooling system.
[0014] In steady state operation of the engine, when the circulation of cooling fluid through
the radiator is activated, the cooling fluid leaving the radiator returns to the engine
through the main line of the cooling system, but, when the aforesaid auxiliary pump
is activated, the cooling fluid also flows through the aforesaid auxiliary line, so
as to provide also cooling of the recirculated exhaust gases in the low-pressure EGR
circuit. Instead, during the warm-up step, after turning on the engine, when the circulation
through the radiator is not activated, most of the flow of cooling fluid leaving the
engine passes through the oil cooler and, if necessary, the passenger compartment
heater, and then returns to the engine inlet, while, if the aforesaid auxiliary pump
is not activated, there is no flow of the fluid in the aforesaid auxiliary line. In
this condition, the amount of fluid that is heated in the engine is less than the
entire capacity of the cooling system, so that the warm-up step is shortened. When,
however, during the warm-up step, the auxiliary pump is activated, it generates an
independent circulation of cooling fluid from the auxiliary line to the main line
(in a reversed circulation direction with respect to that of normal operation) so
as to obtain cooling of the recirculated exhaust gases in the low-pressure EGR circuit
already during warm-up.
Detailed description of a preferred embodiment
[0015] Further characteristics and advantages of the invention will become apparent from
the following description with reference to the appended Figure 1, provided purely
by way of non-limiting example, which illustrates a diagram of a preferred embodiment
of the internal combustion engine according to the invention.
[0016] In Figure 1, numeral 1 designates, in its entirety, a cooling system of an internal
combustion engine 2 including a circuit portion 100 inside the engine 2 and a circuit
portion 101 outside the engine. The engine portion 101 outside the engine includes
a heat exchanger for cooling the engine lubrication oil (oil cooler) designated by
reference 3. The oil cooler 3 is connected to the circuit in such a way that the cooling
fluid leaving the engine flows through a line 4 and through the oil cooler 3, and
then through a line 5 towards the inlet of a main pump 6 serving to activate the circulation
of the cooling fluid in the circuit. The pump 6, which in the most conventional solution
is mechanically driven by the engine shaft, causes the cooling fluid to flow back
into the engine. In parallel to the line 4, a line 7 is provided through which the
cooling fluid leaving the engine flows through a passenger compartment heater 8 and
then flows again through the line 5 towards the pump 6 and to the inlet of the inner
circuit inside the engine.
[0017] The attached drawing does not show the details relating to the aforesaid connections
or to any regulation valves interposed therein.
[0018] According to the prior art, the line 4 leaving the engine 2 also flows through a
heat exchanger 9 for cooling the recirculated exhaust gases in a high-pressure EGR
circuit.
[0019] The outlet of the cooling circuit system from the engine is also connected by means
of a valve 10 to the inlet of a radiator 11 for cooling the engine cooling fluid.
The valve 10 can be thermostatically-controlled, or electronically-controlled, according
to any prior art. When it is opened, the valve causes the cooling fluid leaving the
engine to flow into a line 12 that flows into the inlet of the radiator 11. The radiator
11 outlet is connected through a main line 13 to the inlet of the pump 6, in such
a way that the cooling fluid that flows through the radiator 11, when the valve 10
is opened, is made to flow from the pump 6 back into the engine again.
[0020] Reference number 14 designates a heat exchanger for cooling recirculated exhaust
gases in a low-pressure EGR circuit that is associated with the engine 2.
[0021] In the embodiment illustrated herein, the cooling system comprises an auxiliary line
15 arranged in parallel to the main line 13 that leaves at a point A of the main line
13 and flows again into the main line 13 at a point B, downstream of point A. An auxiliary
pump 16 is inserted into the auxiliary line 15, this pump being preferably driven
by an electric motor controlled by the electronic control unit of the cooling system
of the engine, for example in a PWM mode
[0022] In steady state operation of the engine 2, when the valve 10 is opened, the cooling
fluid leaving the engine flows, in part, through the line 12 into the radiator 11,
and from there it returns, through the main line 13, to the inlet of the pump 6 and
inside the engine. Still according to the prior art, in this condition of steady state
operation, part of the cooling flow passes through the heat exchanger 9, and by means
of the line 4, is then conveyed through the oil cooler 3, and then returns to the
pump 6 inlet and inside the engine 2. If the electronic control unit activates the
heating of the passenger compartment, in a way known per se, there is also a flow
of cooling fluid through the line 7 and through the passenger heater 8, whereupon
the cooling fluid returns to the inlet of the main pump 6 and into the engine.
[0023] In the aforesaid operating condition, whenever the electronic control system must
activate cooling of the recirculated exhaust gases in the low-pressure EGR circuit,
the system activates the electric pump 16, in such a way that the fluid leaving the
radiator 11 flows along both the main line 13 and the auxiliary line 15, through the
exchanger with recirculated exhaust gases in the low-pressure EGR circuit. The flows
along the main line 13 and the auxiliary line 15 converge together at point B of the
main line to then return to the inlet of the main pump 6 and then inside the engine.
[0024] During warm-up, when the valve 10 is closed and the circulation through the radiator
11 is deactivated, the flow of the cooling fluid through the oil cooler 3 and possibly
through the passenger compartment heater 8 is anyhow implemented, according to the
conventional art. In this stage, if activation is required of the cooling of the recirculated
exhaust gases in the low-pressure EGR circuit, the electronic control unit activates
the electric pump 16 to activate a flow of cooling fluid through the auxiliary line
15 and through the heat exchanger 14. In this case, an auxiliary circulation of the
cooling fluid is created through the auxiliary line 15 from point A to point B, after
which the cooling fluid flows along the main line in the reverse direction with respect
to that of normal operation, i.e. from point B to point A, to close the circuit again
through the auxiliary line 15.
[0025] The attached Figure 1 shows a preferred embodiment in which the system also comprises
an additional line 17 starting from the auxiliary line 15 at a point C downstream
of the auxiliary pump 16 and passing through a heat exchanger 18 for cooling a urea
solution injector forming part of a catalytic regeneration system of the exhaust gases
associated with the engine 2. The line 17 ends in the expansion vessel for the cooling
system. The chamber 20 is connected to the line 12 of the cooling circuit by means
of an additional line 21, according to a conventional technique (degassing circuit)
[0026] As can be seen, the internal combustion engine according to the invention includes
an auxiliary circuit, formed of the auxiliary line 15 and the pump 16, and optionally
by the additional line 17, which is a sort of separate system, which can be easily
added to a cooling system suitable for an engine with a simpler configuration when
this engine must be provided with additional components and equipment that also require
cooling.
[0027] Naturally, without prejudice to the principle of the invention, the details of construction
and the embodiments may vary widely with respect to those described and illustrated
purely by way of example, without departing from the scope of the present invention
as defined in the claims.
1. An internal combustion engine for a motor vehicle, with a cooling system comprising:
- a circuit (1) for an engine cooling fluid, including an inner circuit portion (100)
inside the engine (2) and an outer circuit portion (101) outside the engine (2),
- wherein said outer circuit portion (101) outside the engine includes:
- a main pump (6) to activate a circulation of the cooling fluid in the circuit (1),
- an oil cooler (3) for the lubrication oil of the engine, disposed along an oil cooler
line (4) connecting an engine outlet of said inner circuit portion with an inlet of
said main pump (6), in such a way that cooling fluid leaving the engine passes through
said oil cooler (3) and returns towards said main pump (6) to be fed again into the
engine (2),
- a heater (8) for the passenger compartment of the motor-vehicle, connected in the
circuit in such a way that cooling fluid leaving the engine passes through said passenger
compartment heater (8) and returns towards said main pump (6) to be fed again into
the engine,
- a radiator (11) for cooling the cooling fluid, connected in the circuit in such
a way that cooling fluid leaving the engine passes through said radiator (11) and
returns towards said main pump (6) to be fed again into the engine,
- a thermostatically-controlled or electronically-controlled distribution valve (10)
to regulate the flow of cooling fluid leaving the engine towards the radiator (11),
- a high-pressure exhaust gas recirculation circuit cooler (9) for cooling recirculated
exhaust gases in a high-pressure exhaust gas recirculation circuit, connected to the
engine cooling circuit in such a way that cooling fluid leaving the engine passes
through said high-pressure exhaust gas recirculation circuit cooler (9) and returns
towards said main pump (6) to be fed again into the engine, and
- a low-pressure exhaust gas recirculation circuit cooler (14) for cooling recirculated
exhaust gases in a low-pressure exhaust gas recirculation circuit, inserted into said
cooling circuit (1),
wherein:
- the radiator outlet (11) is connected to the inlet of the cooling circuit in the
engine, both by a main line (13), and by an auxiliary line (15) arranged in parallel
to the main line, in such a way that cooling fluid leaving the radiator (11) can flow
into the engine, passing through said main line (13) and through said auxiliary line
(15),
- said low-pressure exhaust gas recirculation circuit cooler (14) is inserted along
said auxiliary line (15) so that it is traversed by cooling fluid flowing along said
auxiliary line (15), and
- an auxiliary pump (16) is inserted along said auxiliary line (15), which is adapted
to be activated only when a flow through said auxiliary line (15) and through said
low-pressure exhaust gas recirculation cooler (14) is required,
said engine being
characterized in that:
- the high-pressure exhaust gas recirculation circuit cooler (9) is disposed along
said oil cooler line (4) upstream of said oil cooler (3) so that cooling fluid leaving
the engine passes through said high-pressure exhaust gas recirculation circuit cooler
(9) before passing through said oil cooler (3),
- said distribution valve (10) is disposed along a line between said engine outlet
and the inlet of the radiator (11),
- said auxiliary line (15) starts from a first point (A) of the main line (13) downstream
of the outlet of the radiator (11) and converges into the main line (13) at a second
point (B) downstream of the first point (A) and upstream of the main pump (6).
2. An internal combustion engine according to claim 1, characterized in that said auxiliary pump (16) is driven by an electric motor.
3. An internal combustion engine according to claim 2, characterized in that it comprises an additional line (17) starting from said auxiliary line (15), downstream
of said auxiliary pump (16) and passing through a cooler (18) of an urea solution
injector forming part of a catalytic regeneration system associated with said engine,
said additional line (17) terminating in an expansion vessel (20) forming part of
the cooling system.
1. Brennkraftmaschine für ein Kraftfahrzeug mit einem Kühlsystem, umfassend:
- einen Kreislauf (1) für ein Maschinenkühlfluid, der einen inneren Kreislaufabschnitt
(100) innerhalb der Maschine (2) und einen äußeren Kreislaufabschnitt (101) außerhalb
der Maschine (2) umfasst,
- wobei der äußere Kreislaufabschnitt (101) außerhalb der Maschine umfasst:
- eine Hauptpumpe (6) zur Aktivierung einer Zirkulation des Kühlfluids in dem Kreislauf
(1),
- einen Ölkühler (3) für das Schmieröl der Maschine, der entlang einer Ölkühlerleitung
(4) angeordnet ist, die einen Maschinenauslass des inneren Kreislaufabschnitts mit
einem Einlass der Hauptpumpe (6) derart verbindet, dass Kühlfluid, das die Maschine
verlässt, durch den Ölkühler (3) strömt und zur Hauptpumpe (6) zurückkehrt, um wieder
in die Maschine (2) eingespeist zu werden,
- eine Heizeinrichtung (8) für den Fahrgastraum des Kraftfahrzeugs, die derart in
den Kreislauf geschaltet ist, dass die die Maschine verlassende Kühlflüssigkeit durch
die Fahrgastraumheizeinrichtung (8) strömt und in Richtung der Hauptpumpe (6) zurückkehrt,
um wieder in die Maschine eingespeist zu werden,
- einen Radiator (11) zum Kühlen des Kühlfluids, der so in den Kreislauf geschaltet
ist, dass Kühlfluid, das die Maschine verlässt, durch den Radiator (11) strömt und
zur Hauptpumpe (6) zurückkehrt, um wieder in die Maschine eingespeist zu werden;
- ein thermostatisch gesteuertes oder elektronisch gesteuertes Verteilerventil (10)
zum Regulieren des Kühlfluidstroms, der die Maschine in Richtung des Radiators (11)
verlässt,
- einen Hochdruck-Abgasrückführungskreislaufkühler (9) zum Kühlen von rückgeführten
Abgasen in einem Hochdruck-Abgasrückführungskreislaufkühler, der so mit dem Maschinenkühlkreislauf
verbunden ist, dass das die Maschine verlassende Kühlfluid diesen Hochdruck-Abgasrückführungskreislaufkühler
(9) durchströmt und zu der Hauptpumpe (6) zurückkehrt, um wieder in die Maschine eingespeist
zu werden, und
- einen Niederdruck-Abgasrückführungskreislaufkühler (14) zum Kühlen von rückgeführten
Abgasen in einem Niederdruck-Abgasrückführungskreislaufkühler, der in den Kühlkreislauf
(1) eingesetzt ist, wobei:
- der Radiatorauslass (11) mit dem Einlass des Kühlkreislaufs in der Maschine sowohl
über eine Hauptleitung (13) als auch über eine Hilfsleitung (15) verbunden ist, die
parallel zur Hauptleitung angeordnet ist, so dass Kühlfluid, das den Radiator (11)
verlässt, in die Maschine strömen kann und die Hauptleitung (13) sowie die Hilfsleitung
(15) durchlaufen kann,
- der Niederdruck-Abgasrückführungskreislaufkühler (14) entlang der Hilfsleitung (15)
so eingefügt ist, dass er von Kühlfluid durchströmt wird, das entlang der Hilfsleitung
(15) strömt, und
- entlang der Hilfsleitung (15) eine Hilfspumpe (16) eingefügt ist, die nur aktiviert
werden kann, wenn ein Fluss durch die Hilfsleitung (15) und durch den Niederdruck-Abgasrückführungskühler
(14) erforderlich ist;
wobei die Maschine
dadurch gekennzeichnet ist, dass
- der Hochdruck-Abgasrückführungskreislaufkühler (9) entlang der Ölkühlerleitung (4)
stromaufwärts des Ölkühlers (3) angeordnet ist, so dass das die Maschine verlassende
Kühlfluid durch den Hochdruck-Abgasrückführungskreislaufkühler (9) vor dem Durchlaufen
des Ölkühlers (3) strömt,
- das Verteilerventil (10) entlang einer Linie zwischen dem Maschinenauslass und dem
Einlass des Kühlers (11) angeordnet ist,
- die Hilfsleitung (15) von einem ersten Punkt (A) der Hauptleitung (13) stromabwärts
des Auslasses des Kühlers (11) ausgeht und in die Hauptleitung (13) an einem zweiten
Punkt (B) stromabwärts von dem ersten Punkt (A) und stromaufwärts von der Hauptpumpe
(6) konvergiert.
2. Brennkraftmaschine nach Anspruch 1, dadurch gekennzeichnet, dass die Hilfspumpe (16) von einem Elektromotor angetrieben wird.
3. Brennkraftmaschine nach Anspruch 2, dadurch gekennzeichnet, dass sie eine zusätzliche Leitung (17) aufweist, die von der Hilfsleitung (15) stromabwärts
der Hilfspumpe (16) ausgeht und durch einen Kühler (18) eines Harnstofflösungseinspritzers
verläuft, der einen Teil eines katalytischen Regeneriersystems bildet, das mit der
Maschine verbunden ist, wobei die zusätzliche Leitung (17) in einem Ausdehnungsgefäß
(20) endet, das einen Teil des Kühlsystems bildet.
1. Moteur à combustion interne pour un véhicule automobile, ayant un système de refroidissement
comprenant :
- un circuit (1) pour un fluide de refroidissement de moteur, comportant une partie
de circuit interne (100) à l'intérieur du moteur (2) et une partie de circuit externe
(101) à l'extérieur du moteur (2),
- où ladite partie de circuit externe (101) à l'extérieur du moteur comporte :
- une pompe principale (6) pour activer une circulation du fluide de refroidissement
dans le circuit (1),
- un refroidisseur d'huile (3) pour l'huile de lubrification du moteur, disposé le
long d'une conduite de refroidisseur d'huile (4) reliant une sortie de moteur de ladite
partie de circuit interne à une entrée de ladite pompe principale (6), de sorte que
le fluide de refroidissement quittant le moteur passe à travers ledit refroidisseur
d'huile (3) et retourne vers ladite pompe principale (6) pour être réintroduit dans
le moteur (2),
- un dispositif de chauffage (8) pour l'habitacle du véhicule automobile, relié dans
le circuit de sorte que le fluide de refroidissement quittant le moteur passe à travers
ledit dispositif de chauffage d'habitacle (8) et retourne vers ladite pompe principale
(6) pour être réintroduit dans le moteur,
- un radiateur (11) pour refroidir le fluide de refroidissement, relié dans le circuit
de sorte que le fluide de refroidissement quittant le moteur passe à travers ledit
radiateur (11) et retourne vers ladite pompe principale (6) pour être réintroduit
dans le moteur,
- une soupape de distribution (10) à commande thermostatique ou à commande électronique
pour réguler le débit de fluide de refroidissement quittant le moteur vers le radiateur
(11),
- un refroidisseur de circuit de recirculation de gaz d'échappement à haute pression
(9) pour refroidir les gaz d'échappement remis en circulation dans un circuit de recirculation
de gaz d'échappement à haute pression, relié au circuit de refroidissement de moteur
de sorte que le fluide de refroidissement quittant le moteur passe à travers ledit
refroidisseur de circuit de recirculation de gaz d'échappement à haute pression (9)
et retourne vers ladite pompe principale (6) pour être réintroduit dans le moteur,
et
- un refroidisseur de circuit de recirculation de gaz d'échappement à basse pression
(14) pour refroidir les gaz d'échappement remis en circulation dans un circuit de
recirculation de gaz d'échappement à basse pression, inséré dans ledit circuit de
refroidissement (1),
dans lequel :
- la sortie de radiateur (11) est reliée à l'entrée du circuit de refroidissement
dans le moteur, à la fois par une conduite principale (13) et par une conduite auxiliaire
(15) agencée parallèlement à la conduite principale, de sorte que le fluide de refroidissement
quittant le radiateur (11) puisse s'écouler dans le moteur en passant à travers ladite
conduite principale (13) et à travers ladite conduite auxiliaire (15),
- ledit refroidisseur de circuit de recirculation de gaz d'échappement à basse pression
(14) est inséré le long de ladite conduite auxiliaire (15) de sorte qu'il soit traversé
par un fluide de refroidissement s'écoulant le long de ladite conduite auxiliaire
(15), et
- une pompe auxiliaire (16) est insérée le long de ladite conduite auxiliaire (15),
qui est adaptée pour être activée uniquement lorsqu'un écoulement à travers ladite
conduite auxiliaire (15) et à travers ledit refroidisseur de recirculation de gaz
d'échappement à basse pression (14) est requis,
ledit moteur étant
caractérisé en ce que :
- le refroidisseur de circuit de recirculation de gaz d'échappement à haute pression
(9) est disposé le long de ladite conduite de refroidisseur d'huile (4) en amont dudit
refroidisseur d'huile (3) de sorte que le fluide de refroidissement quittant le moteur
passe à travers ledit refroidisseur de circuit de recirculation de gaz d'échappement
à haute pression (9) avant de passer à travers ledit refroidisseur d'huile (3),
- ladite soupape de distribution (10) est disposée le long d'une conduite entre ladite
sortie de moteur et l'entrée du radiateur (11),
- ladite conduite auxiliaire (15) part d'un premier point (A) de la conduite principale
(13) en aval de la sortie du radiateur (11) et converge dans la conduite principale
(13) en un deuxième point (B) en aval du premier point (A) et en amont de la pompe
principale (6).
2. Moteur à combustion interne selon la revendication 1, caractérisé en ce que ladite pompe auxiliaire (16) est entraînée par un moteur électrique.
3. Moteur à combustion interne selon la revendication 2, caractérisé en ce qu'il comprend une conduite supplémentaire (17) partant de ladite conduite auxiliaire
(15), en aval de ladite pompe auxiliaire (16) et passant à travers un refroidisseur
(18) d'un injecteur de solution d'urée faisant partie d'un système de régénération
catalytique associé audit moteur, ladite conduite supplémentaire (17) se terminant
dans un récipient d'expansion (20) faisant partie du système de refroidissement.