Information
-
Patent Grant
-
6177653
-
Patent Number
6,177,653
-
Date Filed
Wednesday, August 18, 199924 years ago
-
Date Issued
Tuesday, January 23, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 219 270
- 219 544
- 219 260
- 123 145 A
- 123 145 R
-
International Classifications
-
Abstract
An ion sensor glow plug assembly includes a shell for attachment to a cylinder head of a compression ignition engine and having a passageway extending axially therethrough. The ion sensor glow plug assembly also includes an insulator disposed at least partially in the passageway of the shell and having an aperture extending axially therethrough. The ion sensor glow plug assembly includes a glow bulb made of an insulative material and including a heating element disposed therein. The glow bulb extends through the aperture and into the passageway of the shell and is operatively connected to a source of power to create a heating circuit. The ion sensor glow plug assembly further includes a conductive material extending axially along the glow bulb and operatively connected to a source of power to create an ion sensing circuit.
Description
TECHNICAL FIELD
The present invention relates generally to glow plugs for engines and, more particularly, to an ion sensor glow plug assembly for an engine of a vehicle.
BACKGROUND OF THE INVENTION
It is known to provide an ion sensor for an engine of a vehicle. The ion sensor is used as a closed loop feedback to detect fuel injection timing and intensity of combustion in each cylinder of the engine so as to control and improve engine performance.
It is also known to provide a glow plug for a compression ignition engine such as a diesel engine. The glow plug typically has a ceramic tip that extends into a chamber of the engine. The purpose of the glow plug is to aid in cold starting of the diesel engine. Heat is conducted by conduction from the heating element through the ceramic tip and then by radiation and convection to the fuel-air mixture, which is a slow heat transfer process.
Although the above ion sensors and glow plugs have worked, it is desirable to combine the two to provide an ion sensor glow plug assembly. It is also desirable to provide an ion sensor glow plug assembly that heats quickly a fuel-air mixture in a compression ignition engine such as a diesel engine of a vehicle.
SUMMARY OF THE INVENTION
It is, therefore, one object of the present invention to provide an ion sensor glow plug assembly for an engine of a vehicle.
It is another object of the present invention to provide an ion sensor glow plug assembly that heats by radiation a fuel-air mixture in a compression ignition engine of a vehicle.
To achieve the foregoing objects, the present invention is an ion sensor glow plug assembly including a shell for attachment to a cylinder head of a compression ignition engine and having a passageway extending axially therethrough. The ion sensor glow plug assembly also includes an insulator disposed at least partially in the passageway of the shell and having an aperture extending axially therethrough. The ion sensor glow plug assembly includes a glow bulb made of an insulative material and including a heating element disposed therein. The glow bulb extends through the aperture and into the passageway of the shell and is operatively connected to a source of power to create a heating circuit. The ion sensor glow plug assembly further includes a conductive material extending axially along the glow bulb and operatively connected to a source of power to create an ion sensing circuit.
One advantage of the present invention is that an ion sensor glow plug assembly is provided for an engine of a vehicle. Another advantage of the present invention is that the ion sensor glow plug assembly incorporates a quartz bulb to heat quickly a fuel-air mixture by radiation in a compression ignition engine such as a diesel engine. Yet another advantage of the present invention is that the ion sensor glow plug assembly incorporates a tungsten heating element inside a quartz bulb or rod. Still another advantage of the present invention is that the ion sensor glow plug assembly can be used as a plain glow plug with a quartz bulb using radiation as the heat transfer medium by removing certain elements thereof. A further advantage of the present invention is that the ion sensor glow plug assembly aids in engine cold start and allows closed loop feedback control of engine timing and fueling of a compression ignition engine such as a diesel engine.
Other objects, features and advantages of the present invention will be readily appreciated, as the same becomes better understood after reading the subsequent description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a fragmentary elevational view of an ion sensor glow plug assembly, according to the present invention, illustrated in operational relationship with an engine of a vehicle.
FIG. 2
is a view similar to
FIG. 1
of the ion sensor glow plug assembly illustrated in operational relationship with another engine.
FIG. 3
is a fragmentary elevational view of the ion sensor glow plug assembly of
FIGS. 1 and 2
.
FIG. 4
is an enlarged fragmentary elevational view of a portion of the ion sensor glow plug assembly of FIG.
3
.
FIG. 5
is an enlarged fragmentary elevational side view of the portion of the ion sensor glow plug assembly of FIG.
4
.
FIG. 6
is an enlarged fragmentary elevational view of another embodiment, according to the present invention, of the ion sensor glow plug assembly of
FIGS. 1 and 2
.
FIG. 7
is an enlarged fragmentary elevational side view of the ion sensor glow plug assembly of FIG.
6
.
FIG. 8
is an enlarged fragmentary elevational view of yet another embodiment, according to the present invention, of the ion sensor glow plug assembly of
FIGS. 1 and 2
.
FIG. 9
is an enlarged fragmentary elevational side view of the ion sensor glow plug assembly of FIG.
8
.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings and in particular
FIGS. 1 and 2
, one embodiment of an ion sensor glow plug assembly
10
, according to the present invention, is shown for a compression ignition engine, generally indicated at
12
, such as a diesel engine in a vehicle (not shown). As illustrated in
FIG. 1
, the compression ignition engine
12
may be an open chamber type diesel engine including a cylinder block
14
defining a cylinder
16
closed by a cylinder head
18
. The compression ignition engine
12
also includes a piston
20
reciprocal in the cylinder
16
and defines a recessed bowl, which together with the cylinder head
18
forms a combustion chamber
22
. The compression ignition engine
12
includes an injection nozzle or injector
24
mounted in the cylinder head
18
which sprays fuel into the combustion chamber
22
for compression ignition therein. The compression ignition engine
12
further includes the ion sensor glow plug assembly
10
mounted in the cylinder head
18
and extending into the combustion chamber
22
for a function to be described. It should be appreciated that, except for the ion sensor glow plug assembly
10
, the compression ignition engine
12
is conventional and known in the art.
As illustrated in
FIG. 2
, the compression ignition engine
12
may be pre-chamber type diesel engine including a cylinder block
30
defining a cylinder
32
closed by a cylinder head
34
. The compression ignition engine
12
also includes a piston
36
reciprocal in the cylinder
32
. The piston
36
and cylinder head
34
form a combustion chamber
38
, which connects with a pre-combustion chamber or pre-chamber
40
within the cylinder head
34
. The compression ignition engine
12
includes an injection nozzle or injector
42
mounted in the cylinder head
34
for injecting fuel into the pre-chamber
40
. The compression ignition engine
12
includes the ion sensor glow plug assembly
10
mounted in the cylinder head
34
and extending into the pre-chamber
40
for a function to be described. It should be appreciated that, except for the ion sensor glow plug assembly
10
, the compression ignition engine
12
is conventional and known in the art.
Referring to
FIGS. 3 through 5
, the ion sensor glow plug assembly
10
includes a housing or shell
46
extending axially for engaging the cylinder head
18
,
34
. The shell
46
is generally cylindrical in shape and has a passageway
48
extending axially therethrough. The shell
46
has a plurality of exterior threads
50
for threaded engagement with the cylinder head
18
,
34
. The exterior threads
50
are of a ten millimeter (10 mm) type. The shell
46
has a reduced diameter end
52
adjacent one end of the exterior threads
50
and a hexagonal shaped end
54
adjacent the other end of the exterior threads
50
for a function to be described. The hexagonal shaped end
54
is of a ten millimeter (10 mm) type. The shell
46
is made of a metal material such as steel.
The ion sensor glow plug assembly
10
may include a seal
56
disposed partially in the passageway
48
at the hexagonal shaped end
54
of the shell
46
and an electrical connector (not shown) disposed adjacent the seal
56
for a function to be described. The seal
56
is made of either a plastic or elastomeric material. It should be appreciated that the electrical connector is conventional and known in the art.
The ion sensor glow plug assembly
10
also includes an insulator
60
partially disposed in the passageway
48
at the reduced diameter end
52
of the shell
46
. The insulator
60
is a sleeve being generally cylindrical in shape and extending axially. The insulator
60
has a passageway
62
extending axially therethrough. The insulator
60
is secured to the shell
46
by suitable means such as brazing or adhesively. The insulator
60
is made of a ceramic material such as alumina or Al2O3.
The ion sensor glow plug assembly
10
includes a glow bulb
64
partially disposed in the passageway
48
of the reduced diameter end
52
of the shell
46
. The glow bulb
64
is generally bulb shaped and has a bulb portion
66
and a stem portion
68
extending axially from the bulb portion
66
. The glow bulb
64
has an ion sensing area
70
at the tip of the bulb portion
66
and an ion sensing stripe
72
extending spaced axially from the ion sensing area
70
along an outer surface of the bulb portion
66
and stem portion
68
. The ion sensing area
70
and ion sensing stripe
72
are made from a conductive material such as a platinum ink which are painted or cemented to the outer surface of the glow bulb
64
and then cured at elevated temperature to adhere the conductive material to the glow bulb
64
. The stem portion
68
of the glow bulb
64
extends axially from the bulb portion
66
through the aperture
62
of the insulator
60
and into the passageway
48
if the shell
46
. The stem portion
68
is secured to the insulator
60
by suitable means such brazing. The glow bulb
64
is made of an insulative material such as quartz.
The ion sensor glow plug assembly
10
includes a first electrode
74
and a second electrode
76
spaced radially and extending axially through the stem portion
68
of the glow bulb
64
and terminating inside the bulb portion
66
of the glow bulb
64
. The first electrode
74
and second electrode
76
are made of a conductive material such as Invar or Super-Invar, which are known materials in the art. The ion sensor glow plug assembly
10
also includes a heating element
78
disposed in the bulb portion
66
and interconnecting the ends of the first electrode
74
and second electrode
76
. The heating element
78
is spaced axially from the tip of the bulb portion
66
. The heating element
78
has one end welded to the end of the first electrode
74
and another end welded to the end of the second electrode
76
. The heating element
78
is made of a conductive material such as tungsten (W) in the form of a coiled wire. It should be appreciated that the first electrode
74
, second electrode
76
and heating element
78
are molded inside the glow bulb
64
.
The ion sensor glow plug assembly
10
includes a gas
80
trapped inside the bulb portion
66
of the glow bulb
64
. The gas
80
is an inert gas such as Argon or Nitrogen. The gas
80
creates an internal partial pressure inside the bulb portion
66
of the glow bulb
64
.
The ion sensor glow plug assembly
10
includes a cap
82
disposed over a free end of the stem portion
68
of the glow bulb
64
. The cap
82
is generally cylindrical in shape and has an aperture
84
extending axially therethrough to allow the first electrode
74
and second electrode
76
to extend through the cap
82
without contacting the cap
82
. The cap
82
is made of a metal material and retained by suitable means such as brazing to the glow bulb
64
. It should be appreciated that the cap
82
contacts the ion sensing stripe
72
.
The ion sensor glow plug assembly
10
includes a first insulated or heater terminal
86
extending through the seal
56
and attached to the first electrode
74
by suitable means such as welding. The first insulated terminal
86
matingly engages the electrical connector. The first insulated terminal
86
is made of a metal material such as nickel (Ni). The ion sensor glow plug assembly
10
also includes a second insulated or heater terminal
88
extending through the seal
56
and attached to the second electrode
76
by suitable means such as welding. The second insulated terminal
88
matingly engages the electrical connector. The second insulated terminal
88
is made of a metal material such as nickel (Ni). The ion sensor glow plug assembly
10
further includes a third insulated or ion terminal
90
extending through the seal
56
and attached to the cap
82
by suitable means such as welding. The third insulated terminal
90
matingly engages the electrical connector. The third insulated terminal
90
is made of a metal material such as nickel (Ni). It should be appreciated that the first insulated terminal
86
and first electrode
74
are a first heater terminal for the heating element
78
and the second insulated terminal
88
and second electrode
76
are a second heater terminal for the heating element
78
. It should also be appreciated that the third insulated terminal
90
, cap
82
, ion sensing strip
72
and ion sensing area
70
form an ion sensing circuit.
To assemble the ion sensor glow plug assembly
10
, the heating element
78
is joined such as by welding to the first electrode
74
and second electrode
76
. The heating element
78
, first electrode
74
and second electrode
76
are trapped inside the bulb portion
66
and stem portion
68
of the glow bulb
64
. Trapped inside the bulb portion
66
is the gas
80
to create an internal partial pressure. The ion sensing area
70
at the tip of the bulb portion
66
and ion sensing stripe
72
along the outer surface of the bulb portion
66
and stem portion
68
are painted or cemented to the bulb
64
and then cured at elevated temperature to adhere them to the glow bulb
64
. The insulator
60
and cap
82
are brazed or cemented to the glow bulb
64
. The first insulated terminal
86
is joined or attached to the first electrode
74
by suitable means such as welding. The second insulated terminal
88
is joined or attached to the second electrode
76
by suitable means such as welding. The third insulated terminal
90
is joined or attached to the cap
82
by suitable means such as welding. The insulator
60
is then inserted into the passageway
48
and joined or attached to the shell
46
by suitable means such as brazing. The seal
56
is then inserted into the upper or open end of the passageway
48
of the shell
46
. The ion sensor glow plug assembly
10
is then completely assembled.
In operation of the ion sensor glow plug assembly
10
, current flows from the electrical connector to the first insulated terminal
86
, which passes through the first electrode
74
and heating element
78
and second electrode
76
and second insulated terminal
88
back to the electrical connector to form a glow plug circuit. Heating of the fuel-air mixture, in this case, is mainly by radiation through the quartz material of the glow bulb
64
, which is faster than heating by conduction and convection. The third insulated terminal
90
, cap
82
, ion sensor stripe
72
and ion sensor area
70
carry the supply voltage from the electrical connector for the ion sensor circuit. When there is combustion in the cylinder
16
,
32
, the burnt gases are ionized and conduct or carry current from the electrical connector through the third insulated terminal
90
to the cap, ion sensor stripe
72
and ion sensor area
70
and through the ionized gas to an engine ground, which is the piston
22
,
36
or the shell
46
. It should be appreciated that removing the ion sensing area
70
, ion sensing stripe
72
, metal cap
82
and terminal
90
will allow the assembly
10
to operate as a plain glow plug with a quartz material glow bulb
64
using radiation as the heat transfer medium.
Referring to
FIGS. 6 and 7
, another embodiment
110
, according to the present invention, of the ion sensor glow plug assembly
10
is shown. Like parts of the ion sensor glow plug assembly
10
have like reference numerals increased by one hundred (100). In this embodiment, the ion sensor glow plug assembly
110
includes the glow bulb
164
having a hollow first stem portion
168
. The first electrode
174
may terminate before or be shorter than the second electrode
176
in the bulb portion
166
. The first electrode
174
, second electrode
176
and heating element
178
are inserted and positioned inside the bulb portion
166
and first stem portion
168
. The ion sensor glow plug assembly
110
also includes a second stem portion
192
disposed in the open end of the first stem portion
168
. The second stem portion
192
is then softened by heating and pinched shut around the first electrode
174
and second electrode
176
. The inside of the glow bulb
164
is filled with the inert gas
180
. The ion sensor glow plug assembly
110
operates similar to the ion sensor glow plug assembly
10
.
Referring to
FIGS. 8 and 9
, yet another embodiment
210
, according to the present invention, of the ion sensor glow plug assembly
10
is shown. Like parts of the ion sensor glow plug assembly
10
have like reference numerals increased by two hundred (200). In this embodiment, the ion sensor glow plug assembly
210
includes the glow bulb
264
as a solid rod of quartz material extending axially. The first electrode
274
may terminate before or be shorter than the second electrode
276
in the glow bulb
264
. The first electrode
274
, second electrode
276
and heating element
278
are molded inside the rod for the glow bulb
264
. The ion sensor glow plug assembly
210
also includes a coating
294
about the heating element
278
to prevent cracking or shattering of the quartz rod for the glow bulb
264
by the heating element
278
during operation, due to differential thermal expansion between the heating element
278
and glow bulb
264
. The coating
294
is made of an insulative material such as porous glass or ceramic. The coating
294
is applied to the heating element
278
in the form of a paste and then molded inside the quartz rod of the glow bulb
264
. The coating
294
acts as a cushion for the faster expanding heating element
278
without cracking or shattering the glow bulb
264
during heating operation. The ion sensor glow plug assembly
210
operates similar to the ion sensor glow plug assembly
10
.
The present invention has been described in an illustrative manner. It is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation.
Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the present invention may be practiced other than as specifically described.
Claims
- 1. A glow plug assembly comprising:a shell for attachment to a cylinder head of a compression ignition engine and having a passageway extending axially therethrough; an insulator disposed at least partially in said passageway of said shell and having an aperture extending axially therethrough; and a glow bulb made of an insulative material and including a heating element disposed therein, said glow bulb extending through said aperture and into said passageway of said shell and operatively connected to a source of power to create a heating circuit.
- 2. A glow plug assembly as set forth in claim 1 wherein said insulative material comprises a quartz material.
- 3. A glow plug assembly as set forth in claim 1 wherein said glow bulb has a bulb portion and a stem portion, said stem portion extending axially through said aperture of said insulator.
- 4. A glow plug assembly as set forth in claim 3 wherein said bulb portion is hollow and said stem portion is solid.
- 5. A glow plug assembly as set forth in claim 3 wherein said bulb portion and said stem portion are hollow.
- 6. A glow plug assembly as set forth in claim 1 wherein said glow bulb is a solid rod extending axially through said aperture of said insulator.
- 7. A glow plug assembly as set forth in claim 6 including a coating disposed about said heating element.
- 8. A glow plug assembly as set forth in claim 1 including a first electrode connected to said heating element and a first terminal interconnecting said first electrode and a source of power.
- 9. A glow plug assembly as set forth in claim 8 including a second electrode connected to said heating element and a second terminal interconnecting said second electrode and a source of power.
- 10. A glow plug assembly as set forth in claim 1 wherein said first electrode is shorter than said second electrode.
- 11. A glow plug assembly as set forth in claim 1 including an inert gas disposed in said glow bulb.
- 12. An ion sensor glow plug assembly for a compression ignition engine comprising:a shell for attachment to a cylinder head of a compression ignition engine and having a passageway extending axially therethrough; an insulator disposed at least partially in said passageway of said shell and having an aperture extending axially therethrough; and a glow bulb made of an insulative material and including a heating element disposed therein, said glow bulb extending through said aperture and into said passageway of said shell and operatively connected to a source of power to create a heating circuit; and a conductive material extending axially along said glow bulb and operatively connected to a source of power to create an ion sensing circuit.
- 13. An ion sensor glow plug assembly as set forth in claim 12 wherein said conductive material comprises an ion sensor area at a tip of said glow bulb and an ion sensor stripe extending axially from said ion sensor area.
- 14. An ion sensor glow plug assembly as set forth in claim 13 including a cap disposed over a free end of said glow bulb and operatively connected to a source of power.
- 15. An ion sensor glow plug assembly as set forth in claim 12 wherein said insulative material comprises a quartz material.
- 16. An ion sensor glow plug assembly as set forth in claim 12 wherein said glow bulb has a bulb portion and a stem portion, said stem portion extending axially through said aperture of said insulator.
- 17. An ion sensor glow plug assembly as set forth in claim 16 wherein said bulb portion is hollow and said stem portion is solid.
- 18. An ion sensor glow plug assembly as set forth in claim 16 wherein said bulb portion and said stem portion are hollow.
- 19. An ion sensor glow plug assembly as set forth in claim 12 wherein said glow bulb is a solid rod extending axially through said aperture of said insulator.
- 20. An ion sensor glow plug assembly for a diesel engine comprising:a shell for attachment to a cylinder head of a compression ignition engine and having a passageway extending axially therethrough; an insulator disposed at least partially in said passageway of said shell and having an aperture extending axially therethrough; and a bulb made of an insulative material and having a bulb portion and a stem portion, said bulb including a heating element disposed in said bulb portion and a first electrode and a second electrode connected to said heating element and extending axially through said stem portion, said stem portion extending through said aperture and into said passageway of said shell and said first electrode and said second electrode being operatively connected to a source of power to create a heating circuit; and a conductive material forming an ion sensing area at a tip of said bulb portion and an ion sensing stripe extending axially along said bulb portion and said stem portion and operatively connected to a source of power to create an ion sensing circuit.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4739731 |
Habich et al. |
Apr 1988 |
|
4816643 |
Zulauf et al. |
Mar 1989 |
|
Foreign Referenced Citations (6)
Number |
Date |
Country |
3151825 |
Aug 1982 |
DE |
19737396 |
Mar 1998 |
DE |
19738915 |
Mar 1998 |
DE |
568519 |
Nov 1957 |
IT |
3-267616 |
Nov 1991 |
JP |
9738223 |
Oct 1997 |
WO |