Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23Q—IGNITION; EXTINGUISHING-DEVICES
  • F23Q7/00—Incandescent ignition; Igniters using electrically-produced heat, e.g. lighters for cigarettes; Electrically-heated glowing plugs
  • F23Q7/001—Glowing plugs for internal-combustion engines
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
  • F02P19/00—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition
  • F02P19/02—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition electric, e.g. layout of circuits of apparatus having glowing plugs
  • F02P19/028—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition electric, e.g. layout of circuits of apparatus having glowing plugs the glow plug being combined with or used as a sensor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23Q—IGNITION; EXTINGUISHING-DEVICES
  • F23Q7/00—Incandescent ignition; Igniters using electrically-produced heat, e.g. lighters for cigarettes; Electrically-heated glowing plugs
  • F23Q7/001—Glowing plugs for internal-combustion engines
  • F23Q2007/002—Glowing plugs for internal-combustion engines with sensing means

Definitions

• the present invention relates to a glow plug head and a piezoelectric pressure sensor intended to take place in such a head. It is known to integrate a pressure sensor with a glow plug in an internal combustion engine, in particular a diesel engine. This sensor measures the internal pressure of the engine. Knowing this pressure allows better control of the combustion process in this engine. We then get a better performance from this engine and limit on the one hand its fuel consumption and on the other hand its polluting emissions.
• a glow plug generally comprises a tubular body having on its outer surface a threaded part allowing its fixing in a corresponding bore made in a cylinder head. Part of this body is inside the combustion chamber and the other part outside of it. The part inside the combustion chamber has a finger inside which there is a heating electrode.
• the latter is supplied by a core which passes through the tubular body of the spark plug.
• the part outside the engine is also called the spark plug head.
• the soul is connected to a source of electrical energy.
• the pressure sensor it is also known to place the pressure sensor in this head.
• this sensor For the mounting of such a pressure sensor, it is known to the Applicants, but not yet disclosed by them, to have this sensor in a housing provided for this purpose in the body of the glow plug. On the side opposite the finger integrating the heating electrode, a tapping is carried out and the pressure sensor is thus maintained in its housing by the installation of a nut with external thread.
• the pressure sensor On its other face, the pressure sensor, of the piezoelectric type, rests on a support piece by means of an electrically insulating element and a spacer connects the finger of the spark plug to the support piece.
• the pressure sensor is held by the nut and the spacer retransmits via the support piece (and the electrically insulating element) the forces exerted on it by the pressure inside the room of corresponding combustion.
• This mounting solution firstly has the drawback of requiring significant machining, in particular at the head of the glow plug, in particular at the body of this glow plug.
• the object of the present invention is therefore to provide a mounting of the sensor which makes it possible to overcome these drawbacks and which is in particular of a lower cost price and preferably making it possible to be able to control the prestressing exerted on the pressure sensor.
• the invention provides a glow plug comprising a pressure sensor mounted inside a tubular element and held by means of a support piece in this tubular element. According to the invention, the support piece is held in the tubular element by plastic deformation of the wall of the tubular element.
• the support piece is held by stamping.
• the latter advantageously has, at least over part of its periphery, a frustoconical surface, the large diameter base of the truncated cone being oriented towards the pressure sensor.
• the pressure sensor is a piezoelectric sensor comprising a piezoelectric element mounted between two contact elements, and that the piezoelectric element has an annular shape having at its periphery a flat.
• the piezoelectric element and the contact elements are for example arranged substantially transversely in the tubular element; the contact elements each have at their periphery a connection tab extending substantially longitudinally relative to the tubular element, and the connection tabs are arranged facing the flat of the piezoelectric element.
• the tubular element can comprise an interior wall that is substantially cylindrical circular.
• the tubular element receiving the pressure sensor can be a tubular body, generally called spark plug body, allowing the fixing of the glow plug in an internal combustion engine cylinder head. However, it can also be another part comprising a housing for receiving the pressure sensor. In the case where the pressure sensor is mounted in the spark plug body and the latter is fixed in the cylinder head by screwing and has a gripping zone of hexagonal cross section to facilitate its screwing and unscrewing, then the plastic deformation allowing the maintenance of the support piece is for example made in the vicinity of the gripping area.
• the present invention also relates to an internal combustion engine, in particular a diesel type engine, characterized in that it comprises at least one glow plug as described above.
• FIG. 1 shows in longitudinal section an example of a glow plug prior to the invention
• FIG. 2 shows in side view a glow plug according to invention
• Figure 3 shows in top view and on an enlarged scale the candle of Figure 2
• Figure 4 shows in perspective and on a large scale the piezoelectric sensor of the candle of Figures 2 and 3 with a piece of corresponding support.
• FIG. 1 shows in longitudinal section a glow plug of a model prior to the invention (but not disclosed at the time of the first filing of this patent application).
• This spark plug has a pressure sensor so that it can measure the pressure in an engine cylinder.
• This glow plug 2 is conventionally mounted in an engine 4, of the diesel type, and more precisely in a cylinder head 6 of this engine. It comprises a body 8, a finger 10, a core 12 and a pressure sensor 14.
• the body 8 is adapted to be fixed to the motor 4 by screwing.
• the cylinder head 6 has a threaded bore passing through it and opening into a combustion chamber of said engine.
• the body 8 has meanwhile on its outer surface a thread 16 corresponding to the thread made in the cylinder head 6.
• the body 8 is a tubular body and is for example made of steel.
• the finger 10 is mounted inside the tubular body 8, in which it is tightened, and protrudes inside the combustion chamber.
• This finger 10 incorporates a heating electrode (not shown).
• the core 12 is intended to supply electrical energy to this electrode and passes through the body 8 from the finger 10 to the end of the body 8 opposite to that from which the finger 10 projects.
• This core 12 is then connected, by means not shown, to a supply conductor.
• the pressure sensor 14 is provided for measuring the pressure at inside the corresponding combustion chamber.
• this pressure sensor 14 comprises a piezoelectric element 18 disposed between two contact elements 20 made of an electrically conductive material. The sensor is then itself electrically isolated from the rest of the glow plug 2 by electrically insulating elements 22. In this embodiment, the pressure sensor 14 also comes to bear via a support piece 24 on the body 8. The pressure sensor 14 is secured to the body 8 by its upper surface and bears against the finger 10 so that the pressure exerted on this finger compresses it against the body 8. For this purpose, the sensor pressure 14 is supported on a spacer 38 which rests on the finger 10 and which is arranged in the body 8.
• FIG. 2 shows an external view of a glow plug according to the invention.
• This candle has in longitudinal section for example a structure almost similar to that shown in Figure 1. Any other candle structure can of course also be considered here.
• the elements of a candle according to the invention similar to those of the candle shown in Figure 1 will be designated with the same references.
• the spark plug is oriented and that its head, comprising in particular the pressure sensor, is in the high position while the finger of this glow plug, being inside the engine, is considered to be in the low position.
• the spark plug according to the invention also has a housing 48 similar to the housing 48 in FIG. 1.
• a second support piece 50 takes place. The latter comes to close the upper open face of the housing 48.
• the closure of this housing 48 was provided by a nut with external thread, which also served as a support piece for the piezoelectric sensor, the second support piece 50 is here maintained by stamping. During the stamping operation, the side wall 46 of the housing 48 is plastically deformed so as to trap the second support piece 50.
• stamping the side wall 46 of the housing 48 is plastically deformed so as to trap the second support piece 50.
• the body 8 of the glow plug has, at its head, a gripping area 54 of hexagonal cross section.
• This grip zone 54 is used for screwing and unscrewing the glow plug in the cylinder head 6.
• the head of the glow plug of FIG. 2 comprises in its lower part the hexagonal grip zone 54. Above this gripping zone, the head of the glow plug has a circular cylindrical peripheral outer surface. The stamping is then carried out in this circular cylindrical zone located above the gripping zone 54.
• the piezoelectric pressure sensor is of generally annular shape (a hole central is provided for the passage of the core 12) having at its periphery a flat 56.
• the piezoelectric element 18, the contact elements 20 as well as the second support piece 50 resume this annular shape having a flat 56
• the contact elements 20 and the piezoelectric element 18 are arranged transversely with respect to the housing 48 receiving them.
• Each contact element 20 carries a connection tab 58 extending perpendicular to the plane of the corresponding contact element 20.
• These connection tabs 58 therefore extend longitudinally relative to the housing 48 and extend substantially parallel to the core 12.
• FIG. 3 the fact of providing a flat 56 in the pressure sensor 14 makes it possible to accommodate the pressure sensor 14 in the housing 48 without having to provide a notch or the like in the side wall 46 of this housing in order to allow the passage of the connection tabs 58.
• FIG. 3 the fact of providing a flat 56 in the pressure sensor 14 makes it possible to accommodate the pressure sensor 14 in the housing 48 without having to provide a notch or the like in the side wall 46 of this housing in order to allow the passage of the connection tabs 58.
• the second part d 'support 50 has a slightly frustoconical shape.
• the diameter of the underside of this second support piece 50 that is to say the face oriented towards the pressure 14, is slightly greater than the diameter of the upper face of this second support piece 50.
• the side wall 46 at least partially matches this frustoconical shape and this guarantees the perfect maintenance of this second support piece 50 in the housing 48.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Measuring Fluid Pressure (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=34945458

Family Applications (1)

Country Status (6)

Families Citing this family (7)

Citations (1)

Family Cites Families (8)

• 2004
  • 2004-04-27 FR FR0404467A patent/FR2869394B1/fr not_active Expired - Fee Related
• 2005
  • 2005-04-19 US US11/587,652 patent/US20070209625A1/en not_active Abandoned
  • 2005-04-19 JP JP2007510069A patent/JP2007534921A/ja active Pending
  • 2005-04-19 EP EP05757945A patent/EP1747403A1/de not_active Withdrawn
  • 2005-04-19 CN CNA2005800133093A patent/CN101103231A/zh active Pending
  • 2005-04-19 WO PCT/FR2005/000935 patent/WO2005111504A1/fr active Application Filing

Patent Citations (1)

Non-Patent Citations (1)

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