4,282,754
`fut]
`[45]
`Aug. 11, 1981
`
`
`4,166,451
`4,186,604
`
`Salera ..
`9/1979
`.. 13/362 AR
`
`2/1980 Mattilaccc
`ceeteeeeete 73/346 X
`
`United States Patent 11
`
`Provasnik
`
`[54]
`
`TEMPERATURE SENSOR FOR MEASURING
`THE TEMPERATURE OF AN ENGINE
`Inventor: Robert Provasnik, Holland, Pa.
`[75]
`[73] Assignee:
`Siemens Corporation, Iselin, N.J
`:
`»
`NA,
`Pl Apph Nox Sass
`[22]. Filed:
`Nov. 15, 1979
`15]
`3
`*
`.
`bo we ve ee ous Sseass:
`
`[58] Field of Search..
`were 31346, 343 R:
`Se 338122 R
`
`[56]
`
`Primary Examiner—Daniel M.Yasich
`Attorney, Agent, or Firm—Spellman, Joel & Pelton
`[57]
`ABSTRACT
`A temperature sensor for an engine such as an automo-
`g
`p
`tive engine, which sensor comprises in combination an
`electric heat sensitive device such as preferably a
`thermistor, a contact board and a housing. One of the
`surfaces of the magnet magnetically attaches the sensor
`to the engine. The magnet has an aperture for housing
`the heat sensitive device which is retained within the
`aperture by a heat-conductive material. The contact
`References Cited
`board connects the leads of the heat sensitive device
`U.S. PATENT DOCUMENTS
`with leads of a cable which may be connected to an
`~
`
`
`1,692,301 11/1928—Heslewaod ....cecesccsecrereseees 73/346 indicating device. The housing of the sensor, made of an
`Stapleton a
`: myne electrically insvlating material, partially encloses the
`2,279,846
`4/1942
`
`aa43 R
`aecee ase, elserene
`‘agnet, thereby leaving open a surface for magnetic
`
`2/1965 Powell
`" 94/346 X
`3.170327
`attachment to a ferromagnetic part of the engine, the
`Flaugher et al.
`cece. 73/343 R
`3,302,107
`1/1967
`‘temperature of which is to be determined.
`
`. 13/362 AR
`3,552,210
`1/1971 Wright, Ir. ......
`
`
`4,079,350 3/1978—Sentementes csosssesenees 338/22 R 6 Claims, 4 Drawing Figures
`
`
`
`POAOOOLODOOM,
`
`96
`48
`62
`20
`
`
`
`
`#¢—KSIR ececanreras
`IS Y SKRN
`BAS NG
`
`a—N(
`8
`30
`
`26
`2
`:
`10
`4
`
`|
`
`2
`
`2
`
`Page 1 of 5
`
`EX1009
`Petitioner Hum (223)
`
`EX1009
`Petitioner Hum (223)
`
`
`Page 1 of 5
`
`

`

`U.S. Patent
`
`Aug. 11, 1981
`
`4,282,754
`
`FIG. 3
`
`14
`
`24
`
`42
`
`18
`
`
`
`Page 2 of 5
`
`
`Page 2 of 5
`
`

`

`1
`
`4,282,754
`
`2
`retained within the aperture of the magnet by a heat-
`conductive material such as Wakefield Delta Bond 152.
`Theelectrical leads of the heat sensitive device extend
`out of the aperture. They are electrically connected to
`electrical connection points, which are comprised by
`the electrical contact means. The housing is made of an
`electrically insulating material. The housing partially
`encloses the magnet and the contact board,
`leaving
`open the magnetic contact surface of the magnet.
`According to a preferred embodiment of the inven-
`tion, the contact means comprises an electrically insu-
`lating board and two electrically conductive strips
`thereon. Theelectrical connection points are formed on
`the conductive strips. In this embodiment, the usually
`very thin leads of the heat sensitive device can be elec-
`trically connected to first points on said strips, and the
`comparatively thick leads of an electric lead capable
`can be electrically connected to remote second points
`on said strips. Thus an electric connection can easily be
`performed.
`the
`According to another preferred embodiment,
`magnet is of cylindrical shape. The clearance opening
`of the magnet is formed along the longitudinal axis
`thereof and extends entirely throughout the magnet.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The foregoing and other objects, features and advan-
`tages of the invention will be apparent from the follow-
`ing more particular descriptions of preferred embodi-
`ments of the invention asillustrated in the accompany-
`ing drawings.
`In the drawings:
`FIG.1 is a general view of a temperature sensor,
`partially in cross-section, for measuring the temperature
`of an automobile engine;
`FIG.2 is a plan view of the magnetic contact side of
`the temperature sensor according to FIG.1;
`FIG. 3 is a representation of the electrical. circuit
`whichis used in thé sensor of FIG. 1; and
`FIG. 4 is an enlarged isometric view of a contact
`board shownin FIG. 1.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`
`TEMPERATURE SENSOR FOR MEASURING THE
`TEMPERATUREOF AN ENGINE
`
`BACKGROUNDOF THE INVENTION
`1. Field of the Invention
`This invention relates to a novel and improved tem-
`perature sensor for measuring the temperatures of an
`engine, particularly of an internal combustion engine.
`Moreparticularly, this invention relates to a tempera-
`ture sensor which is not
`installed permanently but
`which can readily be attached to and removed from the
`engine. Still more particularly, this invention relates to
`a temperature sensor which can be used as a tempera-
`ture probe of an automotive engine analyzer.
`2. Description of the Prior Art
`In the field of automotive engine analysis,it is neces-
`sary to measure various temperatures, such as the en-
`gine block temperature, the engine oil temperature and
`other temperatures of engine parts and operations or
`subsystems. For this purpose there are needed tempera-
`ture sensors or probes which can easily be attached to
`and removed from the engine. There are various ways
`to attach a temperature probe to the engine block. De-
`vices which are used in automotive analysis include
`clips, in the first line so-called allegator clips, washer
`type bolt-on units, cartridges, etc. From U.S. Pat. No.
`3,302,107, FIGS. 16-182, it is also knownto insert a
`temperature sensor throughtheoil dipstick tube into the
`engine oil. This sensor provides a direct reading of the
`oil temperature of the engine. However, the procedure
`of inserting the temperature probe into the small oil
`dipstick tube is time consuming, causes oil residue and
`requires cleaning of the probe after each measurement.
`SUMMARYOF THE INVENTION
`
`1. Objects
`An object of this invention is to provide a tempera-
`ture sensor for easily measuring the temperature of an
`engine.
`/
`Another object of this invention is to provide a tem-
`perature sensor for measuring the temperature of an
`engine, which sensor can easily and quickly be attached
`to and removed from the engine.
`Another object of this invention is to provide a tem-
`perature sensor which is comparatively small and com-
`pact and allows for fast temperature readings.
`Another object of this invention is to provide a tem-
`perature sensor which can be used for repeated mea-
`surements under rough environmental conditions.
`Another object of this invention is to provide a tem-
`perature sensor which is very well suited for automo-
`tive garages and repair shops,particularly in connection
`with an automotive engine analyzer.
`Another object of this invention is to provide a tem-
`perature sensor which allows for measuring the temper-
`ature of the engine oil of an automobile engine without
`inserting a temperature sensitive device through theoil
`dip-stick tube into the engineoil.
`
`2. Summary
`
`5
`
`25
`
`30
`
`35
`
`45
`
`55
`
`60
`
`With reference to FIGS. 1 and 2, a temperature sen-
`sor is shown which can be used as part of an engine
`analyzer to measure the temperature at various loca-
`tions of an automobile engine. Particularly, the sensor
`shown.in the drawingshas been found useful to measure
`the temperature of the engine oil. The sensor incorpo-
`rates the advantage that there is no necessity that it be
`inserted into the oil itself when a reading is taken.
`The temperature sensor is mounted within a magnet 2
`for magnetic attachment to any part 4 of an engine
`where a temperature reading is desirable. Part 4 may
`represent the automobile engine block, particularly that
`part of the engine block which contains the engineoil.
`By measuring the temperature of part 4, the tempera-
`ture of the oil can be detected.
`‘
`Forthe purpose of magnetic attachmentto part 4, the
`magnet 2 has a surface 6 which has the same shape as
`Accordingto this invention, a temperature sensor for
`the surface of part 4. As shown in the embodiment of
`measuring the temperature of an engine comprises a
`FIG. 1, magnet2 and part 4 haveflat and even surfaces.
`magnet, a heat sensitive device, electrical contact means
`65
`These surfaces could also be curved.
`and a housing. The magnet has an aperture therein. The
`The magnet 2 in FIGS. 1 and2is of the pot-type; in
`magnet further has a contact surface for magnetically
`attaching it to the engine. The heat sensitive device,
`other words, it is of cylindrical shape. The surface 6 is
`such as a thermistor, has electrical leads. The device is
`formed by oneof the two endsof the cylinder. The two
`
`Page 3 of 5
`
`
`Page 3 of 5
`
`

`

`4,282,754
`
`— 5
`
`25
`
`30
`
`3
`ends of the magnet 2 represent-a magnetic pole, respec-
`tively. The lower endis the surface 6.
`An important feature of the magnet 2 is that it has an
`aperture 8 therein. This aperture 8 is formed along the
`longitudinal axis of the cylinder. Aperture 8 is a bore
`which extends throughout
`the magnet 2.
`In other
`words: the magnet 2 has a cylindrical hole through its
`center. The aperture 8 contains an electric heat sensitive
`device 10, particularly a temperature sensitive resistor
`(thermistor) of small size. The electric resistance of a
`thermistor varies according to the temperature to
`whichit is exposed. Instead of a thermistor, a tempera-
`ture sensitive device 10 can be used which delivers a
`voltage in accordance to the temperature applied.
`In the aperture 8, which serves for protection pur-
`poses, the heat sensitive device 10 is arranged at the
`lowerend of the magnet2 close to the outer surface 6 to
`obtain true temperature readings. The heat sensitive
`device 10 has at least two electrical leads 12 and 14
`which extend out of the upper end of the aperture 8.
`-The heat sensitive device 10 is retained within the
`aperture 8 by a heat conductive material, which is
`shown in FIG. 1 by scoring or hatching. The magnet 2
`and the heat conductive material form a flat surface
`adjacent to the part 4. Thus, the magnet 2 will hold the
`heat sensitive device 10 to most any part 4 of the engine
`and its various sub-systems (which are generally made
`of iron or its alloys) where it is desirable to measure
`temperatures. Generally speaking, the magnet-tempera-
`ture sensitive device combinatior. 2-10 can be used to
`determine the temperature of any part 4 which is of
`ferromagnetic structure. Due to the heat conductive
`material, there is essentially no temperature difference
`between part 4 and the heat sensitive device 10.
`‘Preferably the aperture 8 is used to cement a thermis- 3
`tor with any of the well known heat conductive epoxys,
`such as Wakefield, Delta Bond 152. The thermistor is
`the actual temperature sensing element. Its resistance
`and thereby the temperature can be determined by
`known means, for example,
`in a Wheatstone bridge.
`Arranged close to the magnet 2 is an electrical contact
`device 21 which serves to form an electrical contact
`between the heat sensitive device leads 12 and 14 and
`the lead-out leads 16 and 18, respectively, of an electric
`lead-out cable 20. This contact device 21 comprises two
`first electrical connection points 22 and 24 (see FIG. 4)
`to whichthe leads 12 and 14, respectively, of heat sensi-
`tive device 10 are corinected.
`For ease of lead attachment and handling of the heat
`sensitive device 10, an electrically insulating board 26
`with two electrically conductive strips 28, 30 on the
`surface thereof can be used, as shown in FIGS. i and 4.
`Thefirst connection points 22 and 24 are formed on the
`surface of the strips 28 and 30, respectively. Strips 28
`and 30 are shownto be broaderin FIG. 4 than in FIG.
`1. They are arranged in spaced, parallel relationship
`electrically insulated from each other. The board 26 is
`shownto be preferably of rectangular shape: This board
`26 can be a well knownsingle-sided printed circuit with
`two solder tracks which are used as conductivestrips 28
`and 390.
`:
`As shown in FIGS. 1 and 4, the contact board 26 has
`a clearance opening 32 for leading the electrical leads 12
`and 14 therethrough from the heat sensitive device 10 to
`the connection points 22 and 24, respectively. The
`clearance opening 32,drilled through the center of the
`board 26,is arranged between the twostrips 28 and 30.
`To avoid short circuits, the leads 42 and 14 of the heat
`
`4
`sensitive device 10 are provided with sleevings 34 and
`36, respectively, as may be seen in FIG. 4.
`As can be seen in FIG.4, the lead-out cable leads 16
`and 18 are connected to two second connection points
`40 and 42, which are arranged on thestrips 28 and 30
`remotely from the first connection points 22 and 24.
`The leads 16 and 18 are also provided with sleevings 44
`and 46, as shown in FIGS. 1 and 4.
`Asillustrated in FIG. 1, a cord retainer 48 is secured
`to one end of the lead-out cable 20. To the other end
`there is connected a connector 50 of conventional type.
`As shownin FIG.3, the connector 50 has two measur-
`ing pins, a key pin 52 and a shield pin 54. Theshield pin
`54 is connected to an electric shield, which shields cable
`20.
`Referring to FIG. 1, a housing or boot 56 encloses the
`contact board 26 together with its connection points 22,
`24, 40, 42, and partially encloses also the magnet 2,
`thereby leaving open the flat surface 6 of the magnet 2.
`As can be seen in FIG. 1, the housing 56 has approxi-
`mately the samesize as the connector 50. The housing
`56 is madeofan electrically insulating material, particu-
`larly of an elastic material. Preferably it
`is made of
`silicon rubber. The housing 56 is formed as to hold the
`magnet 2 by its front or measuring portion, circumfer-
`entially encompassing thereby the magnet 2. The open
`end portion of the housing 56 has a rim 58 adjacent to
`part 4, which is arranged essentially in the same plane as
`the surface 6 of the magnet 2.
`Theinterior 60 of the housing 56 is hollow. The con-
`nection points 22, 24, 40, 42 extend into this hollow
`interior,
`thereby protecting the electrical connection
`from thermal and mechanical influences.
`The housing 56 further has an outlet portion 62. This
`outlet portion 62 serves for leading the lead-out cable 20
`out of the housing 56 approximately parallel
`to the
`surface 6 of the magnet 2. This parallel arrangement
`simplifies the handling of the sensor by the operator.
`The provision of the board assembly 26, 28 and 20 per-
`mits the attachment of the very thin leads 12, 14 to
`connection points 22, 24, respectively. It further permits
`convenient connection of the leads 16, 18 (which are
`usually of much larger diameter) electrically to the heat
`sensitive device 10. The electrical connections may be
`soldered.
`The temperature sensor may be assembledas follows:
`After soldering leads 12 and 14 to connection points 22
`and 24, the heat sensitive device 10 is passed through
`the clearance hole 32, see FIG. 4. This device-board
`assembly is then attached to the upperside of magnet 2.
`The aperture 8 and the clearance hole 32 are aligned
`with each other. The device-board assembly is prefera-
`bly cemented with a heat-conductive epoxy thereon, so
`that the sensoris close to the flat magnet face. The cord
`retainer 48 is then secured to the magnet end of the
`cable 20 to prevent the leads 16, 18 from being pulled
`through the insulating housing 56 which is now placed
`over the cable 20 and the magnet-device assembly2, 10
`and secured in place. The housing 56 desirably may be
`molded on the magnet assembly. This can be easily
`doneif it is made of silicon rubber. The housing 56 acts
`as a thermal insulation, shielding the magnet 2 and the
`heat sensitive device 10 from airblast from a cooling fan
`of the automobile engine.
`The temperature sensor shown in FIG.1-4 is rugged
`and thus very well suited ta a use in automotive garages
`and repair shops. The magnetic retention facilitates
`attachment and subsequent removal. Due to the small
`
`40
`
`45
`
`Page 4 of 5
`
`
`Page 4 of 5
`
`

`

`4,282,754
`
`5
`mass, the temperature sensor has verylittle heat-sinking
`effect thus providing for fast measurement times. The
`tubber housing 56 providing thermal! insulation and
`impact protection during any rough treatment it may
`receive during use. Measurements have shownthat the
`difference between the temperature measured by a prior
`art heat-sensitive device inserted through the dip-stick
`tube into the engine oil and the temperature measured
`by the present device when attached to the engine block
`containing motoroil, is insignificant.
`While the form of the heat-sensing device herein
`described constitutes a preferred embodiment of the
`invention, it is to be understood that the invention is not
`limited to this precise form of assembly, and that a vari-
`ety of changes may be madetherein without departing
`from the scope of the invention.
`Whatis claimedis:
`
`1. A temperature sensor for measuring the tempera-
`ture of an automobile engine, comprising:
`(a) a magnet of cylindrical shape having
`(al) a longitudinal axis, an aperture being formed
`along said axis and extending through said mag-
`net,
`(a2) a first flat end surface, and
`(a3) a second flat end surface for magnetic attach-
`ment to said engine;
`(b) an electric heat sensitive device for temperature
`measurements, said device having electrical leads
`and being retained within said aperture by a heat-
`conductive material, and said electrical leads ex-
`tending out of said aperture at said first flat end
`surface;
`(c) an electrical insulating board attached tosaid first
`surface of said magnet, said board having
`
`6
`(cl) a clearance opening for leading said electrical
`leads therethrough, and
`(c2) electrical connection points on elongated
`contact means mounted on the free surface of
`said insulating board, said leads from said heat
`sensitive device being electrically connected
`respectively to said points;
`(d) a lead-out cable having lead-out leads, said lead-
`out leads being spacedly electrically connected via
`said contact meansrespectively to said connection
`points; and
`insulating housing of an elastic and
`(e) a thermal
`electrical insulating material, said housing enclos-
`ing said board and said connecting points and cir-
`cumferentially encompassing and holding said
`magnet, thereby leaving open said second surface
`of said magnet, and said housing comprises an out-
`let portion for leading said lead-out cable out of
`said housing approximately parallel to said second
`surface of said magnet.
`2. The temperature sensor according to claim 1,
`wherein said board has a rectangular
`shape, and
`wherein said clearance opening is arranged centrally
`3. The temperature sensor according to claim 1,
`wherein said housing is madeof silicon rubber.
`4. The temperature sensor according to claim 1,
`wherein said housing has an opening, said opening hav-
`ing a rim essentially in the same plane as said second
`surface of said magnet.
`5. The temperature sensor according to claim 1,
`wherein said board is attached to said magnet by a heat
`conductive material.
`6. The temperature sensor according to claim 1,
`wherein said heat-conductive material forms a plane
`which is arranged in the same plane as said second
`surface of said magnet.*
`oe
` %
`*
`*
`
`a 5
`
`25
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`Page 5 of 5
`
`
`Page 5 of 5
`
`