Liquid monitoring apparatus

• US 4,745,895 A
• Filed: 03/27/1987
• Issued: 05/24/1988
• Est. Priority Date: 10/15/1985
• Status: Expired due to Fees

• Current Assignee: Briggs & Stratton Corporation
• Original Assignee: Briggs & Stratton Corporation
• Inventors: Hajec, Edward B., Seilenbinder, Richard W.
• Primary Examiner(s): Tokar, Michael J.
• Assistant Examiner(s): Raevis, Robert R.
• Application Number:
  US07/032,985
• Time in Patent Office: 424 Days
• Field of Search: 73/118, 73/304 R, 73/304 C, 73/118.1, 123/196 S, 123/198 DC, 184/6.4, 340/620, 340/59, 116/227
• US Class Current: 123/196.00S
• CPC Class Codes: G01F 23/242 Mounting arrangements for electrodes

Abstract

An electrically responsive oil level sensor is mounted within a vehicle oil sump. An enclosure encloses the ends of two spaced electrodes. The high voltage electrode has a pointed end and the other low voltage electrode has a blunt end opposed to the pointed end. The low voltage electrode is connected to ground in series with an indicator. The enclosure has three vertically spaced openings. An entrance opening is aligned with the electrode gap for in flow of oil. A second is located below the entrance opening and establishes a restricted oil outflow. The third opening is above the entrance opening for air and fume escapement. A baffle is interposed between the entrance opening and the electrode gap. The baffle prevents the motion of the oil in the sump from moving directly through the entrance opening and into the electrode gap. The enclosure has an integral tower for the high voltage electrode and the tower has annular radial projections to increase the surface creepage path.

Claims

1. A submersible sensor adapted to be immersed in a submerging liquid within a containing means for sensing electrically different conductive mediums in said liquid, said submerging liquid having a minimum selected level and a maximum selected level in said containing means, comprising first and second electrodes spaced from each other with opposed ends to define a sensing gap, means in said sensing gap between said electrodes to vary the conductivity of the gap with the conductivity of the mediums in said gap, a flow control enclosure secured defining a chamber about said opposed ends of said electrodes and said gap, said flow control enclosure having mounting means for attachment to said containing means and said flow control enclosure includes at least one first opening means located to establish flow of said submerging liquid into said chamber at a rapid inflow rate to immerse said opposed ends and at least one second opening means constructed and arranged to establish the flow of said submerging liquid from the chamber at an outflow rate less than said flow rate of said first opening in response to movement of submerging liquid about the enclosure, and said first opening means being located to introduce liquid into said chamber with said liquid level substantially at the minimum selected level and below the maximum level to maintain flow into said first opening means and said liquid in said chamber flowing from said chamber through said second opening means with said submerging liquid substantially at said minimum level and below said minimum level.

2. The sensor of claim 1 wherein said first electrode includes a pointed end, and said second electrode includes a blunt end spaced from said pointed end to form said gap with conduction from the outermost point of said pointed end and in the direction of said pointed end to the blunt end.

3. The sensor of claim 1 wherein said first electrode is connected to a high tension voltage source and said second electrode is connected to a ground return lead, and a control means is connected in series in said return lead.

4. The sensor of claim 1 including a support for said electrodes and control enclosure and wherein said electrodes have the ends vertically oriented and spaced whereby said sensing gap is vertically oriented, and a keying means on said support to establish said vertical orientation.

5. The sensor of claim 1 wherein said first opening means to said flow control enclosure includes an entrance opening generally aligned with said gap, and means interposed between said entrance opening and said gap to prevent direct entrance of liquid from the exterior of said flow control enclosure into said gap.

6. The sensor of claim 5 wherein said means interposed between said entrance opening and said gap includes a baffle plate means redirecting the incoming liquid laterally of said electrodes and gap.

7. The sensor of claim 6 wherein said enclosure is vertically mounted and said second opening means includes a discharge opening at the lower end, said baffle plate means extends downwardly over said discharge opening and having a discharge opening aligned with said first named discharge opening, the flow rate through the discharge opening in the baffle plate being less than the flow rate through the discharge opening in the enclosure for a given level in said enclosure.

8. The sensor of claim 7 wherein the discharge opening in the baffle plate is slightly less in cross-section than the discharge opening in the enclosure to establish said differential flow rates.

9. A submersible sensor adapted to be immersed in a liquid within a containing means for sensing electrically different conductive mediums in said liquid, said submerging liquid having a minimum selected level and a maximum selected level in said containing means, comprising an insulating support, a high-tension electrode secured in said support and having an L-shaped protion projecting from said support, said L-shaped portion terminating in a pointed end, a second reference rod-like electrode secured in said support and having a blunt end located in opposite spaced realtion to the outer most axial end of said pointed end to define a sensing gap responsive to the conductivity of the medium within said gap and establishing conduction from said pointed end to said blunt end, a flow control enclosure secured to said support and defining a chamber about said electrodes including said ends and said sensing gap, said flow control enclosure having mounting means for attachment to said containing means and said flow control enclosure including at least one first opening means located to establish flow of said submerging liquid into said chamber at a rapid inflow rate to immerse said ends of said electrodes and at least one second opening means constructed and arranged to establish the flow of said submerging liquid from the chamber at an outflow rate less than said inflow rate of said first opening means in response to movement of said submerging liquid about the enclosure, and said first opening means being located to introduce said submerging liquid into said chamber with said liquid level substantially at the minimum selected level and below the maximum level to maintain flow into said first opening means and said liquid in said chamber flowing from said second opening means with said submerging liquid substantially at said minimum level and below said minimum level.

10. The sensor of claim 9 wherein said electrodes have the ends of the elctrodes vertically oriented to form a vertically extending sensing gap, and said support having a keying means to establish said vertical orientation.

11. The sensor of claim 9 wherein said first opening means in said flow control enclosure includes an entrance opening generally aligned with said gap, and a baffle means interposed between said entrance opening and said gap to prevent direct entrance of liquid from the exterior of said enclosure into said flow control gap.

12. The sensor of claim 11 wherein said flow control enclosure is vertically oriented and said second opening means includes a discharge opening located beneath said entrance opening, said baffle means is a plate essentially corresponding to the interior of said enclosure, said plate having laterally spaced opening aligned with said discharge opening of said flow control enclosure, the flow rate through the discharge opening in the baffle plate being less than the flow rate through the discharge opening in the enclosure for a given level in said enclosure.

13. The sensor of claim 12 wherein the discharge opening in the baffle plate is slightly less in cross-section than the discharge opening in the enclosure.

14. The sensor of claim 9 having a high voltage lead connected to said high tension electrode having a pointed end and a return lead connected to said second electrode having said blunt end, a signal means connected in series in said return lead to identify a change in the conductivity of said gap.

15. The sensor of claim 14 for controlling a load and wherein said signal means includes a resistance to limit the current in said gap and thereby maintain operation of the load with conduction through said gap.

16. The sensor of claim 9 wherein said high tension electrode and said reference electrode have connecting ends of differing configuration.

17. The sensor of claim 9 wherein said support is a molded member having said electrodes molded therein and projecting outwardly from opposite sides thereof.

18. The sensor of claim 17 wherein said high voltage electrode is a rod-like member having an exterior terminal end shaped to define a spring means adapted to resiliently engage a tubular terminal, and said reference electrode having a terminal end of a distinctly different shape.

19. The sensor of claim 18 having an insulating tower integrally molded to said support and extending outwardly over said high volatge electrode, said tower including a plurality of annular projections, and said high voltage electrode including an insulating boot of a resilient material and releasably fitted over said tower.

20. A submersible sensor adapted to be immersed in a submerging liquid within a housing for sensing electrically different conductive mediums in said liquid, comprising an insulating support, a high tension electrode secured in said support, a second reference electrode secured in said support and located in opposed spaced relation to said first electrode to define a spark gap responsive to the conductivity of the medium within said gap, a flow control enclosure secured to said support and defining a chamber closely spaced about said electrodes including said gap, said flow control enclosure including at least a first opening to establish flow of a submerging liquid into said chamber to immerse said opposed ends and a second opening for restricted discharge of said liquid from said second opening, said first and second openings being constructed and arranged to delay the flow of liquid from the chamber in response to movement of submerging liquid about the flow control enclosure, and a baffle means interposed between said openings and said gap to prevent direct entrance of the liquid from the exterior of said flow control enclosure through said entrance opening into said gap.

21. The sensor of claim 20 wherein said electrodes are vertically oriented with an upper electrode and a lower electrode, said lower electrode having a blunt end, said upper electrode having a pointed end located in opposed relation to said blunt end of said lower electrode and establishing a conductive path from said pointed end to said blunt end.

22. The sensor of claim 21 wherein said flow control enclosure includes an outer flat end wall having three vertically spaced openings including said first opening generally aligned with said gap, a said second opening is a bottom discharge opening for discharge of said submerging liquid from said flow control enclosure and a top release opening for releasing of air from said flow control enclosure.

23. The sensor of claim 22 wherein baffle means is essentially a solid plate corresponding to the internal configuration of the enclosure adjacent the spark gap and located in spaced relation to said electrodes and said end wall, said plate having edge notches on the side edges generally in alignment with the spark gap and the inlet opening, said baffle unit having openings aligned with said discharge opening and said release opening.

24. The sensor of claim 23 wherein said opening in the baffle plate aligned with said discharge opening has a smaller cross-section than said discharge opening.

25. The sensor of claim 20 wherein said flow control enclosure includes a cup shaped housing having a rectangular shape with a width slightly greater than the thickness of the electrodes and a vertical height slightly greater than the spacing of the electrodes, said housing being releasably secured to the support to define said enclosure, said housing having an outer flat end wall, said first opening being centrally located in said end wall for defining the oil entrance opening, said second opening being a small bottom opening defining the restricted discharge opening, and having a top opening in said end wall defining an air release opening for releasing air from said housing when liquid enters through said oil entrance opening.

26. The sensor of claim 25 wherein said baffle includes a baffle plate secured within said cup shaped housing and located between the electrodes and the outer end wall of said cup shaped housing, said baffle plate having side edge notches with the lower edge of the notch aligned with the entrance opening for free flow of oil around the baffle plate, the bottom end of said baffle plate having a small opening aligned with the discharge opening of said housing, and the upper end of said baffle plate having an opening aligned with said release opening of said housing.

27. The sensor of claim 20 in combination with a liquid sump having a side wall mount opening and wherein said support is a molded plastic member releasably secured within said side wall opening of said liquid sump, said electrodes are rod-like electrodes embedded within and extending through said molded support, said electrodes having inner ends bent to extend toward each other, one of said electrodes having an essentially sharp pointed end, a second of said electrodes having a relatively blunt end, said support member and mounting opening being constructed to establish vertical orientation of said electrodes with said pointed end located above said blunt end.

28. The sensor of claim 20 wherein said support is formed with an integral outwardly extending tower about the high tension electrode, said tower including a plurality of adjacent annular radial projections to significantly increase the surface creepage path to the high tension electrode and thereby minimizes the probability of creation of parasitic currents from the high tension electrode.

29. The sensor of claim 20 wherein said high tension electrode has a U-shaped end and said reference electrode has an end distinctly different shape.

30. The sensor of claim 20 wherein said sensor support is adapted to be secured within a correspondingly shaped sensor opening in the housing and including a clamp bracket having means for securing said clamp bracket to the housing adjacent said sensor opening, said clamp bracket and said sensor support having a plurality of interrelated engaging members restricting placement of said sensor support in said sensor opening in a single orientation.

31. The sensor of claim 30 wherein said clamp bracket includes oppositely extending arms terminating in lateral end projections of a distinctly different cross-section and overlying said sensor support, said sensor support having first and second recesses aligned with and receiving said projections, said recesses having a cross-section corresponding to one of said projections whereby said bracket can be secured to said housing with only one orientation of said sensor support.

32. In combination, an internal combustion engine, a high volatge source in an ignition system and having an oil sump and a splash lubrication means for moving oil from said sump to operating components, said oil having a minimum selected level and a maximum selected level in said sump, a sensor unit comprising a submersible sensor support secured to said sump and immersed in said oil for sensing said oil, a high tension electrode secured to said support and connected to the high voltage source of said ignition system, said high tension elelctrode having a pointed end, and a second reference electrode secured to said support having an outer end located in opposed spaced relation to said pointed end to define a sensing gap responsive to the conductivity of the oil, a flow control enclosure secured to said support and defining a chamber about said electrodes including said ends of said electrodes and said gap, said flow control enclosure including at least one first opening means located to establish flow of said oil into said chamber at a rapid inflow rate to immerse said ends of said electrodes and at least one second opening means constructed and arranged to establish the flow of said oil from the chamber at an outflow rate less than said inflow rate of said first opening means in response to movement of said oil about the enclosure, said first opening means being located to introduce oil into said chamber with said oil level substantially at the minimum selected level and below the maximum level to maintain flow through said chamber and from said second opening means with sadi submerging liquid substantially at said minimum level and below said minimum level, said support and said sump being constructed and arranged whereby said gap is located at the center of said oil in said sump.

33. The combination of claim 32 wherein said electrodes have the ends of the electrode vertically oriented, and said support having a keying means to establish said vertical orientation upon mounting of said support to said sump.

34. The combination of claim 32 wherein said first opening means of said enclosure includes an entrance opening generally aligned with said gap, and a baffle means interposed between said entrance opening and said gap to prevent direct entrance of the oil from the exterior of said enclosure into said gap.

35. The combination of claim 32 wherein said support includes a molded plastic member having said electrodes molded therein.

36. The combination of claim 32 wherein said engine includes at least one spark plug and a magneto for generating a high voltage pulse for firing said spark plug, said magneto including an output coil having a moisture proof covering, first and second high voltage leads connected to said coil and passing through said covering, and sealing means secured to said cover and to said leads to hermetically seal the connection of said leads to said coil, said first high volatge lead being connected to said spark plug, and said second high voltage lead being connected to said high voltage electrode of said sensor.

37. The combination of claim 32 wherein said ignition system includes a high voltage spark plug wire having an outer insulating cover, a T-shaped connector secured to said spark plug wire and establishing a lateral connection threfrom, said T-shaped connector including a T-shaped base member having an elongated base with a lateral tube extension, a conductor in said tubular extension outwardly through said base and terminating in a rigid pointed end, a releasable clamp member releasably affixed to said base and clamping said base member firmly against said spark plug wire to hermetically seal the base to the wire and to move said rigid pointed end through said outer insulator cover.

38. The combination of claim 32 including a spark plug lead connected to said high voltage source, and a separate sensor lead connected to said high voltage source and to said high voltage electrode.

39. The combination of claim 32 including a low level indicator means connected between said reference electrode and ground, said indicator means having sufficient resistance to prevent shorting of the ignition system.

40. The combination of claim 39 wherein said high voltage electrode is a rod-like member having an exterior terminal end shaped to define a spring means adapted to resiliently engage a tubular terminal, and said reference electrode having a terminal end of a distinctly different shape than said exterior terminal end of said high voltage electrode.

41. The combination of claim 32 having an insulating tower secured to said support and extending outwardly over said high voltage electrode, said tower including a plurality of annular projections, and said high voltage electrode including an insulating boot of a resilient material and releasably fitted over said tower.

42. The combination of claim 32 wherein said sump includes a casing having a sump opening, and including a clamp bracket, means securing said clamp bracket to said casing adjacent said sump opening, said bracket and said sensor support having a plurality of interrelated engaging members restricting placement of said sensor support in said opening in a single orientation.

43. The combination of claim 42 wherein said bracket includes oppositely extending arms terminating in lateral end projection of a distinctly different cross-section and overlying said support, said support having first and second recesses aligned with and receiving said projections, said recesses having a cross-section corresponding to one of said projections whereby said bracket cover can be secured to said casing with only one orientation of said support.

44. The combination of claim 32 including an indicating means, a current limiting means, means connecting said indicating means and said current limiting means between said reference electrode and ground, said current limiting means being selected to limit the current flow through said gap to maintain firing of said ignition system.

45. An internal combustion engine having a high volatge ignition system and including a splash lubrication system and having an oil sump with a bottom cover having a sidewall, comprising an electrically responsive sensor means, including an enclosure for enclosing spaced rod-like electrodes defining a sensing gap within a sensing chamber, one of said electrodes being a high voltage electrode to be connected into the high voltage side of the ignition system, the other electrode being a return electrode, a molded plastic support adapted to be releasably secured within a side wall opening of said sump cover, said rod-like electrodes molded within and extending through said molded support in vertically spaced relation to each other, inner ends of said electrodes being bent to extend toward each other, said high voltage electrode having a sharp pointed end, said return electrode having a flat end, a bracket secured to said cover, said support and said bracket having cooperating interengaged members to ensure said vertical orientation of the electrodes with the high voltage electrode located above the return electrode, a housing secured to said support and forming an end wall of the enclosure, said housing having an outer end flat wall spaced slightly from the electrodes, three vertically spaced openings including an inlet opening substantially at the vertical height of the sensing gap for entrance of oil into the enclosure and a second discharge opening located at the lower end of said flat wall for restricted outflow of oil from the enclosure and a third release opening located at the upper end of said flat wall for discharge of air and other fumes within the enclosure, a baffle plate interposed between said flat wall and said sensing gap, said housing being generally rectangular in shape and having a width slightly greater than the thickness of the electrodes and a vertical height slightly greater than the spacing of the electrodes, said baffle plate including small notches on the side edges with the lower end of the notches generally in alignment with the sensor gap and the inlet opening, said baffle plate having upper and lower mounting arms extending to the opposite sides of the plate and frictionally engaging the top and bottom walls of said housing to locate the baffle plate in spaced relation to said flat wall and said electrodes, said baffle plate having a bottom opening of cross-section slightly smaller than the bottom opening in the flat wall and a top opening aligned with the top opening in the flat wall, said support having an intergral outwardly extending tower about the high voltage electrode, said tower including a plurality of adjacent annular radial projections, said high voltage electrode having an outer terminal spring end, a high volatge tension lead having a tubular contact adapted to telescope over said spring end and having an outer resilient boot telescoped over said tower and frictionally gripping said tower, said support locating said sensing gap at the center of the oil sump and at the selected minimum safe oil level, and a high voltage source connected to said high voltage tension lead, a high voltage spark plug lead connected to said source.

46. The engine of claim 45 wherein said high voltage source is a magneto driven in synchronism with said engine and includes an output coil, a spark plug lead, a first hermetically sealed connection means connecting said spark plug lead to said coil, a second hermetically sealed connection means connecting said high tension lead to said coil.

47. The engine of claim 45 wherein a connection means includes a two piece connector encircling said high voltage spark plug lead, said connector including a T-shaped base member having a base wall having a curvature complementing said high voltage spark plug lead and having a stem, a conducting rod in said stem extending through said base member, the opposite ends of said rod having sharp pointed ends, and an outer clamp member releasably secured to said base member and having a curvature complementing said high voltage spark plug lead.