FR2763364A1 - FUEL INJECTOR FOR INTERNAL COMBUSTION ENGINE - Google Patents

Abstract

Fuel injector for an internal combustion engine characterized in that the tightening nut (24) is surrounded at least partially by a sleeve (50), between the tightening nut (24) and the sleeve (50), a coolant volume (51) made watertight vis-à-vis the environment by sealing elements (53, 55), and each time by at least one coolant inlet orifice (52) provided in the sleeve (50), as well as at least one coolant outlet (54) provided in the sleeve, for the coolant (70).

Description

STATE OF THE ART The present invention relates to a injector for

  fuel for an internal combustion engine, in particular a diesel engine comprising an injector body fixed in an injector support by a tightening nut. receiving an obturator (needle) axially sliding and having a sealing surface, for cooperating with a valve seat, fixed for controlling the injection section; and at least one

  injector spring pressing against a fixed stop and acting

  force on the obturating member directed towards the

valve seat.

  Such a fuel injector is known for example according to document DE-44 08 245 A1; this injector is preferably used in internal combustion engines

  Diesel in particular of utility vehicles.

  On sloping journeys, utility vehicles

  res driven by a diesel internal combustion engine, used

  frequently read the continuous pressure brake, i.e.

  the engine brake, which creates a significant rise in temperature

  maple at the fuel injector which can

truce the injector.

  To dissipate this heat, certain injectors

  of heavy oil diesel engines have cooling channels

  directly in the injector body.

  The difficulty with such injectors is that

  apart from the evacuation of heat through the cooling channel

  predetermined is limited and on the other hand the construction

  of the fuel injector is complicated and thus its manufacture

cation becomes very expensive.

  The present invention aims to develop a

  fuel injector corresponding to the type defined above

  above, ensuring efficient cooling with means

technically simple.

  Advantages of the invention To this end, the invention relates to an injector characterized in that the tightening nut is surrounded at least partially by a sleeve; between the tightening nut and the sleeve, a volume of coolant is made which is sealed vis-à-vis the environment by sealing elements, and the coolant passes through at

  at least one coolant inlet port in the sleeve, and at least one coolant outlet port in the sleeve.

  The coolant chamber formed by the sleeve receiving the coolant allows very efficient cooling of the clamping nut and the injector body at the closure member because the coolant passing through the chamber on the clamp nut takes the heat given off at the injector

  and transmits it to the engine coolant

internal bustion.

  The cooling is considerably improved compared to that of the fuel injectors known according to the prior art, and in which the heat released is transmitted to the cooling system only by

  contact points and areas of thin material.

  Thanks to efficient fluid cooling

  cooling through the coolant chamber

  We can considerably reduce the conditions for

  the materials constituting the injector. This allows

  to use usual materials for car injectors

  burant which are refractory up to around 270 C since the

  cooling is effectively guaranteed.

  Strictly speaking, one can realize

  multiple ways to cool the coolant chamber

  is lying. An advantageous embodiment provides that the

  coolant chamber annularly surrounds

the tightening nut.

  We can also consider the modes of realization

  most different for positioning the inlet and / or outlet ports of the coolant. By

  example, the inlet and outlet ports of the coolant

  cooling can be radical holes in the sleeve.

  In particular, to achieve excellent listening

  Lement towards the body of the injector, at the closure member, there is provided, according to a very advantageous embodiment, to incline the inlet and / or outlet ports of the cooling fluid, according a certain angle by

  relative to the axial direction of the injector.

  The sealing elements can also be produced in different ways. According to. an advantageous embodiment, the sealing elements include an O-ring between the sleeve and the injector body of the

  side of the coolant chamber, shaped an-

  ring, opposite the valve seat. Such a seal is mounted in a very simple and inexpensive manner and provides excellent sealing. As the coolant,

  preferably water which has a very large capacity

  lorific and thus allows to absorb heat very well and

evacuate it.

  Drawings The present invention will be described below in more detail with the aid of an embodiment shown in the single figure showing a sectional view

  partial of a fuel injector according to the invention.

  Description of the exemplary embodiment

  A fuel injector for a combustion engine

  internal tion, shown in Figure 1, comprises a shutter member 10 in the form of a piston, for example a needle guided in axial sliding in a bore 12. The shutter member 10 has at its end facing the

  combustion chamber (not shown) of the combustion engine

  internal cone, a conical sealing surface 14 for cooperation

  rer with a valve seat 20, conical at the closed end of the bore 12 facing inward. The injector body

  22 is clamped at its end remote from the control chamber

  bustion, by a tightening nut 24, axially against an injector support 26; between the front surfaces of the injector body 22 and the injector support 26, we tightened

  an intermediate washer with a central hole. To his ex-

  opposite end to the valve seat 20, the needle 10 is biased by a force exerted by means of a pressure piece passing through the intermediate washer 28; this force is exerted by the injector spring in the form of a helical spring 40 pressing against a fixed stop provided on the body 26 and exerting a force on the needle, directed towards its seat 20. Between the sealing surface of valve 14 and valve seat 20 the body wall

  injector 22 has at least one ejection orifice 27

  clogging in the combustion chamber of the internal combustion engine. The application of the high fuel pressure takes place in a manner known per se by an annular channel 13

  made between the body of the injector 22 and the wall of the

  slot 12; this channel 13 widens towards a pressure chamber into which opens a pressure line 43 coming

  an injection pump not shown.

  In the area of the needle 10, the injector body 22 is surrounded by a sleeve 50. Ports

  coolant inlet / outlet 52, 54 are pre-

  seen in the sleeve 50. These orifices are oriented at an angle with an angle relative to the axial direction of the fuel injector. Between the injector body 22 fixed to the support body 26 by means of the tightening nut 24 and the sleeve 50, an annular volume 51 receives the coolant 70 through the inlet / outlet ports 52, 54. The annular volume 51 is sealed against the environment by sealing elements 53, 55. These sealing elements are for example an O-ring 53 provided between the sleeve 50 and the nut. clamping 24 on the side of the annular coolant chamber 51, opposite

at valve seat 20.

  The sleeve 50 is itself mounted in a channel

  coolant 71 filled with coolant

  ment 70. Between the sleeve 50 and a wall 72 delimiting the coolant channel 71, a seal 73, known per se (for example an O-ring) prevents the fluid from escaping

cooling 70.

  During the operation of the internal combustion engine, in particular as an engine brake, the needle 10 as well as the injector body 22 and consequently the clamping nut 24 undergo a considerable rise in temperature. The

  heat is taken up by the coolant 70 back

  through the coolant inlet port 52 into the annular coolant chamber 51. As a result of convection, the coolant 70 heated in the annular coolant volume 51 passes through the outlet 54 in the coolant channel 71. The heat is thus dissipated very efficiently thanks to the flow caused by convection

  in the annular coolant volume 51.

Claims (4)

R E V E N D I C A T IONS   1) Fuel injector for an internal combustion engine, in particular a diesel engine comprising an injector body (22) fixed in an injector support (26) by a clamping nut (24), receiving a shutter member (needle) (10) sliding axially and having a sealing surface (14), to cooperate with a valve seat (20), fixed for controlling the injection section, and at least one injector spring (40) s '' pressing against a fixed stop (41) and exerting on I () the closure member (10) a force directed towards the valve seat (20), characterized in that e the clamping nut (24) is surrounded at least partially by a sleeve (50), * between the clamping nut (24) and the sleeve (50), a volume of coolant (51) is formed which is sealed vis-à-vis the environment by sealing elements (53, 55), and the coolant (70) passes through at least one coolant inlet (52)) into the sleeve (50), and at least one outlet for   coolant (54) in the sleeve.   2) Fuel injector according to claim 1, characterized in that the coolant chamber surrounds the nut   tightening in an annular shape.   3) Fuel injector according to any one of the res-   dications 1 and 2,) characterized in that the coolant inlet and / or the coolant outlet ports (52, 54) are arranged at an angle at an angle to the axial direction of the fuel injector.   4) Fuel injector according to any one of the res-   dications 1 to 3, characterized in that the sealing elements comprise an O-ring (53) between the sleeve (50) and the clamping nut (24) on the side of the coolant chamber (51), annular, opposite the valve seat (20).    ) Fuel injector according to any one of claims 1 to 4, characterized in that   the coolant is cooling water.