Patent Application
20220013993
The present disclosure relates generally to the field of internal combustion engines, and in particular, to ignition systems utilized in such engines. More specifically, the present disclosure provides, inter alia, apparatuses for preparing a suppressor seal of a spark plug insulator assembly, and processes for fabricating and/or assembling a spark plug insulator assembly using the same.
A spark plug (also known as a sparking plug) is a device for delivering electric current from an ignition system to an engine's combustion chamber in order to ignite the compressed fuel/air mixture within the chamber through an electric spark, while containing combustion pressure within the engine. To achieve consistent operation with no ignition miss, a spark plug is designed to ensure positive insulation between spark and cylinder head while also sealing the combustion chamber.
A spark plug includes a terminal stud, an insulator, a shell, a seal seat and electrodes. In a typical spark plug, a metal threaded shell is electrically isolated from a center electrode by a porcelain insulator. The center electrode, which may include a resistor, is connected by a heavily insulated wire to the output terminal of an ignition coil or magneto. The spark plug's metal shell is inserted (usually screwed) into the engine's cylinder head and thus electrically grounded. The center electrode at one end of the insulator protrudes into the combustion chamber, forming one or more spark gaps between the tip of the center electrode and one or more protuberances or structures attached to the inner end of the threaded shell (i.e., the ground (earth) electrode(s)).
Because the spark plug also seals the combustion chamber of the engine when installed, seals (both external and internal) are required to ensure there is no leakage from the combustion chamber. In particular, the internal seal (or suppressor seal) is created inside the spark plug insulator and may also connect the terminal stud and the center electrode. Currently, the preparation of a good suppressor seal inside the spark plug insulator involves a flame heating process, usually fueled by a fuel such as natural gas. Such a process suffers from various drawbacks. For example, given the expensive nature of natural gas (or other fuels), such a process is relatively costly. Such a process also lacks consistency given the variability in the heating effect. The finished product from such process often has relatively large range of suppressor resistance values, which can impair the efficiency of suppressing noise signals generated at the time of spark discharge. Such a process also may require process changes for different product models, such as, e.g., raising or lowering gas burner positions, changing supporting holders, increaings gas flow rate, changing gas air mixture ratio, etc.
Accordingly, there is a need for new and improved apparatuses and processes for creating a suppressor seal of a spark plug insulator assembly, which are energy-efficient, reliable, consistent and cost-effective.
The present disclosure provides improved apparatuses and processes used in producing spark plug insulators. In accordance with some embodiments, the disclosure provides an apparatus that allows heating non-thermally conductive materials with induction heat. Advantages of this technology include, inter alia, significant reductions in energy requirements compared to existing techniques that rely on fuels, e.g., natural gas, as well as improved heat control and efficiency with resultant tighter range in resistance values on the finished product.
According to certain embodiments of the present disclosure, an apparatus for preparing a suppressor seal of a spark plug insulator assembly comprises: (a) a protective housing for the spark plug insulator; (b) a crucible surrounding the housing; (c) an induction heating element placed nearby the outer surface of the crucible; (d) an induction power supply connected to the induction heating element; and (e) a stud press.
The present disclosure also includes a process for fabricating and/or assembling a spark plug insulator assembly according to certain embodiments. Such a process comprises the steps of: (a) filling a spark plug insulator with a seal material; (b) placing the spark plug insulator inside a protective housing; (c) activating an induction power supply and heating the spark plug insulator until an inside temperature of 850-900° C. is reached; (d) inserting an insertion into the spark plug insulator to construct a spark plug insulator assembly; (e) applying a stud press on top of the insertion and holding for approximately one minute; and (f) releasing the stud press and removing the spark plug insulator assembly from the protective housing.
The present disclosure also includes an automated system for fabricating and/or assembling a spark plug insulator assembly according to certain embodiments. Such a system comprises: (a) at least one apparatus configured to prepare a suppressor seal of a spark plug insulator assembly using induction heat; (b) one or more auxiliary units, the one or more auxiliary units being configured to perform the following operations: (i) filling the spark plug insulator with a seal material; (ii) placing a spark plug insulator on the apparatus; (iii) inserting an insertion into the spark plug insulator; (iv) applying and releasing a stud press; and (v) removing the spark plug insulator assembly from the apparatus; and (c) one or more computerized control units, the one or more computerized control units being configured to control operation of the at least one apparatus and the one or more auxiliary units.
To facilitate further description of the embodiments of this disclosure, the following drawings are provided to illustrate and not to limit the scope of the disclosure.
Novel apparatuses for preparing a suppressor seal of a spark plug insulator assembly and processes of producing spark plug insulator assemblies using such apparatuses are provided and described. Various embodiments and modifications are possible and fall within the scope of the present disclosure.
According to certain embodiments of the present disclosure, an apparatus for preparing a suppressor seal of a spark plug insulator assembly comprises: (a) a protective housing for the spark plug insulator; (b) a crucible surrounding the housing; (c) an induction heating element placed nearby the outer surface of the crucible; (d) an induction power supply connected to the induction heating element; and (e) a stud press.
In some embodiments, the protective housing can be selected to accommodate different spark plug insulators or the same spark plug insulator in different orientations. In some embodiments, the protective housing is thermally conductive.
As used herein, the term “crucible” can refer to a ceramic or metal container in which metals or other substances may be melted or subjected to very high temperatures. In the context of the present disclosure, a crucible can be used to transfer heat to the spark plug insulator, which is made or constructed of a material that cannot be directly heated by an induction heating element.
In some embodiments, the crucible is placed in close proximity of the protective housing to efficiently transfer heat. In some embodiments, the crucible is electrically conductive. In some embodiments, the crucible is made of metal or ceramic. In some embodiments, the crucible is made of a material selected from the group consisting of alumina, zircornia, magnesia, quartz, graphite, corundum, pyrolytic boron nitride (PBN), platinum, tungsten, molybdenum, tantalum, nickel, zirconium, silicon carbide, vitreous carbon. In some embodiments, the crucible is made of molybdenum disilicide (MoSi2).
As used herein, “induction heating” can refer to the process of heating an electrically conducting object (e.g., a metal) by electromagnetic induction, through heat generated in the object by eddy currents. In the context of the present disclosure, an “induction heating element” can be the output head of an induction heater powered by an induction power supply.
In some embodiments, the induction heating element can be an induction heating coil winding around the crucible. In some embodiments, the induction heating element can radiantly heat the spark plug insulator up to an inside temperature of 850-900° C.
In some embodiments, the apparatus disclosed herein further comprises a spacer situated in between the crucible and the induction heating element. In some embodiments, the spacer is made of aluminum oxide (Al2O3). In the context of this disclosure, the spacer locates the cruiclbe and protective housing relative to the induction heating coil to constrain the location of these three objects and maintain consistent heating performance over time.
In some embodiments, the stud press can compress and hold an insertion within the spark plug insulator. In the context of the present disclosure, a “stud press” can refer to a tool that can apply pressure (through, e.g., its own weight) on the top of a part or assembly to be processed and hold a desired position for a period of time. In some embodiments, the stud press is automated, e.g., by pnumatic and spring force combined.
In some embodiments, the insertion is a terminal stud or a center electrode.
The present disclosure also includes a process for fabricating and/or assembling a spark plug insulator assembly according to certain embodiments. Such a process comprises the steps of: (a) filling a spark plug insulator with a seal material; (b) placing the spark plug insulator inside a protective housing; (c) activating an induction power supply and heating the spark plug insulator until an inside temperature of 850-900° C. is reached; (d) inserting an insertion into the spark plug insulator to construct a spark plug insulator assembly; (e) applying a stud press on top of the insertion and holding for approximately one minute; and (f) releasing the stud press and removing the spark plug insulator assembly from the protective housing.
As used herein, a “seal material” refers to a material used to prevent leakage and internally connect a terminal stud and a center electrode. In the context of the present disclosure, a seal material can be electrically conductive. It can be made or constructed of compressed glass/metal powder, or a multi-layer braze. The seal material used in the present disclosure can be softened or liquified at a sufficient temperature (e.g., in some cases, approximately 900° C., 850-950° C., or 800-900° C.).
In some embodiments, the seal material is conductive glass.
In some embodiments, the insertion inserted in step (d) of the process above is a terminal stud or a center electrode.
The present disclosure also includes an automated system for fabricating and/or assembling a spark plug insulator assembly according to certain embodiments. Such a system comprises: (a) at least one apparatus configured to prepare a suppressor seal of a spark plug insulator assembly using induction heat; (b) one or more auxiliary units, the one or more auxiliary units being configured to perform the following operations: (i) filling the spark plug insulator with a seal material; (ii) placing a spark plug insulator on the apparatus; (iii) inserting an insertion into the spark plug insulator; (iv) applying and releasing the stud press; and (v) removing the spark plug insulator assembly from the apparatus; and (c) one or more computerized control units, the one or more computerized control units being configured to control operation of the at least one apparatus and the one or more auxiliary units. In some embodiments, the automated system can be configured to process and/or output 10-120 spark plug insulator assemblies per minute.
In the context of the present disclosure, an “auxiliary unit” can refer to one or a plurality of peripheral devices that work and/or coordinate with the apparatus disclosed herein, to implement the desired processes as those disclosed herein, including, e.g., feeding raw materials, operating parts of the apparatus, removing finished products, etc. An auxiliary unit, as used herein, may generally include any means, device, and/or apparatus that is unmanned and/or computer programed.
In some embodiments, the one or more auxiliary units comprise one or more automated robotic arms configured to perform at least one of the operations identified in (i)-(v) of the automated system above.
The following discussion provides examples to further illustrate the present disclosure. These examples are illustrative only and are not intended to limit the scope of the disclosure in any way.
An existing apparatus 100 for implementing a natural gas pressure seal process is shown in
A new apparatus 200 according to an illustrative embodiment of the present disclosure is shown in
A process 300 for assembling a spark plug insulator assembly using the new apparatus disclosed herein is further illustrated in
The exemplary processes described in the present disclosure demonstrated benefits over the existing processes in various aspects, including but not limited to, energy saving, cost saving, and improved performance of the finished products. Specifically, the following experiments were conducted with a prototype of the induction heating apparatus constructed in the laboratory. The test results were compared with those of the currently employed gas heating device under the same work settings (as explained below in details) to verify and document the benfits.
On the existing gas burner setup, the metal burners have a 0.080″ fuel flow orifice with a needle valve throttle and operate at 26 oz/in2 (1.625 psi) of fuel pressure. These parameters are not defined in their manufacturing specification of the burner so a calorimeter measurement was collected. Best results were collected when one of the two burners was applied 2″ from to the bottom of a large thin walled stainless steel vessel with 10 pounds of water in it. Rates of change in water temperature were measured to reach 3 degrees in as little as 15 seconds using a large thermocouple sensor and aggressive stirring. This heating rate suggests that at least 8500 BTU (British thermal units) are being released by each burner and 17000 BTU total. It is worth noting that this is likely an underestimate because heat was escaping around the water filled vessel. That said, this establishes a lower bound of energy input.
The amount of energy for the induction system used in the experiments was collected with a clamp meter reading the electrical current going into the machine, and then converted to BTU for a comparison to gas.
For comparison, prices for energy were used based on average 2019 costs of 1.712 MXN/KWH and 105 MXN/GJ. An approximate 86% decrease on energy consumption was found, which would cut over one-third of the cost (see
Given the production line in a factory is more efficient than the prototype system in a laboratory, efficiency was increased by scaling up the prototype process to the continuous process. The estimated savings on costs can be found in
The test data also showed that the induction heating process described in this disclosure had at least equivalent performance in the electrical resistance of the suppressor seal compared to the natural gas process (demonstrated in
Although illustrative embodiments of the present disclosure have been described herein, it should be understood that the disclosure is not limited to those described, and that various other changes or modifications may be made by one skilled in the art. For example, it should be understood that various omissions and substitutions and changes in the form and details of the systems and methods described and illustrated may be made by those skilled in the art. Amongst other things, the steps in the methods may be carried out in different orders in many cases where such may be appropriate. Further variations, modifications, and implementations may occur to those of ordinary skill in the art without departing from the scope or spirit of the disclosure.
The present application claims benefit of U.S. Provisional Patent Application Ser. No. 63/049,829, filed on Jul. 9, 2020, which application is incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63049829 | Jul 2020 | US |
