Patent Application
20170338589
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The present invention relates to high-voltage extenders for connecting a high-voltage source to a spark plug. More particularly, the present invention relates to extenders that are semi-rigid and which insulate a conductive member that is connected to an ignition coil at one end and a spark plug at an opposite end.
Extenders are often used for the connection of high voltage sources, such as ignition coils, to spark plugs. These high voltage extenders are intended to pass the charge from the high voltage source (having a maximum voltage of 43 KV) to the ignition coils. Typically, these extenders are suitably insulated so as to prevent tracking from the conductive rod to the electrical ground created by the engine block.
As can be seen in
Experiments with the prior art of
Engines that burn natural gas are becoming extremely popular. Natural gas produces low emissions are very economically. Unfortunately, when spark plugs are used to ignite natural gas, they will have a very high temperature (of up to 250° C.). As such, the prior art high-voltage extenders would deteriorate rapidly over time when subjected to such temperatures. As such, a need has developed whereby the high-voltage extender can withstand the high temperatures of such bar plugs of natural gas engines.
In the past, various U.S. patents have issued relating to such high voltage extenders. For example, U.S. Pat. No. 4,944,259, issued on Jul. 31,1990 to R. D. Richardson, teaches an ignition system with an insulated and extendable extender. This extender resiliently biases the extender between the source of high energy and the spark plug to provide a positive and reliable electrical connection therebetween. The extender is of a relatively rigid construction so as to prevent bending. The extender is combined with a shield in the engine to further protect and increase the functional life of the components.
U.S. Pat. No. 5,060,624, issued on Oct. 29, 1991 to Bruning et al., provides an engine ignition system that has a transformer assembly and positioning means. The transformer assembly has an elongated body having a cup portion containing the coils, a base portion, and a stem portion. A conducting core extends through the stem and base portions. A suitable clip connects the core electrically to a spark plug installed in a profiled bore of the cylinder head. A positioning device is provided to positively align and contain the transformer assembly within a valve mechanism compartment defined between the cover and the cylinder head. A spring member connected to the cup portion. Depending guide members formed within the cover cooperate with each other.
U.S. Pat. No. 5,357,233, issued on Oct. 18, 1994 to Z. Wada, teaches an extension device which extends from the ignition coil to supply the peak high-voltage output to a spark plug. A part of an outer periphery of the secondary coil at an intermediate position of the outer periphery of the secondary coil sinks in relation to the other part of the outer periphery of the secondary coil to form a groove extending in a radial direction of the secondary coil. The peak high-voltage output is transmitted from the secondary coil through the groove to the extension device. The extension device includes a first member extending from the ignition coil, a second member for being connected to the spark plug, and an elastic member connecting the first member to the second member so that the first member moves elastically in relation to the second member.
U.S. Pat. No. 5,577,921, issued on Nov. 26, 1996 to Philyaw et al., discloses an electrical connector system for electrically connecting a voltage source to a spark plug terminal. This transformer assembly has an elongate body including a cup portion containing primary and secondary coils, a base portion, and a stem that is adapted to be installed in a housing of a cylinder head. An electrical source extends through the stem and base portion. An electrical connecting system includes an electrical conductor adapted to receive the voltage source with a spring contacting the end of a spark plug terminal biasing the conductor in a direction away from the spark plug. The electrical connector system further includes a positioning device adapted to positively align and contain the transformer assembly within a valve mechanism compartment defined between a cover and the cylinder head. A spring member is connected to the cup portion so as to axially bias the electrical conductor in a direction toward the spring in contact with the spark plug terminal so as to ensure an electrical connection.
U.S. Pat. No. 5,685,282 issued on Nov. 11, 1997 to Murata et al., discloses an ignition device for an internal combustion engine. This ignition device has a spark plug including a high voltage terminal, an ignition coil for generating a high voltage, and adapter assembly for electrically connecting the ignition coil to the high voltage terminal of the spark plug. The adapter assembly has a support sleeve for accommodating and supporting the high voltage terminal of the spark plug against a transverse movement of the high voltage terminal. The support sleeve is either a continuous extension or a metal tube of the adapter assembly. The assembly may also include a wear-resistant material.
U.S. Pat. No. 6,068,495, issued on May 30, 2000 to F. Virchow, discloses a spark plug for an internal combustion engine. A connector sleeve is formed of an insulating material. An elastic member is connected to the connector sleeve so as to seal the gap between the connector sleeve and a spark plug well. A ceramic inlet is formed in the connector sleeve so as to enclose the plug-in contact and the ignition cable connection.
U.S. Pat. No. 6,340,303, issued on Jan. 22, 2002 to Hamada et al., describes a high tension connection for the spark plug of an internal combustion engine. This connection portion has a first high tension connection terminal, a second high tension connection terminal for electrically connecting with the first high tension connection terminal, a locking mechanism provided between the first high tension connection terminal and the second high tension connection terminal for restricting the separation therebetween in the axial direction, and a spring member disposed between the first high tension connection terminal and the second high tension connection terminal. This device serves to prevent an instantaneous breakdown of the connection if an external force is applied to the high tension portion.
U.S. Pat. No. 6,817,872, issued on Nov. 16, 2004 to S. M. Berg, describes a heat-protective spark plug extension. The extender includes an elongated body formed of heat resistant and electrically insulative material that extends between a spark plug engagement end and a spark plug wire connector end. A conductor is located within the body and includes a fitting adapted to releasably electrically connect to a spark plug wire. A receptacle is adapted for electrical connection to a spark plug. An adjustment part permits adjustable movement of the spark plug wire connector end relative to the conductive receptacle.
U.S. Pat. No. 7,594,489, issued on Sep. 29, 2009 to the present Applicant, describes a high-voltage extender for connecting a high-voltage source to a spark plug. The extender has a conductive rod with one end suitable for electrical connection to the high-voltage source and a second end suitable for electrical connection to the spark plug. A sleeve is injection-molded over the conductive rod so as to be in void-free relation with an exterior surface of the conductive rod. The conductive rod has a first end extending outwardly therefrom. The sleeve defines a spark plug-receiving receptacle at the second end of the conductive rod. An O-ring is received in a notch formed adjacent to the first end of the conductive rod. Another O-ring is received in a notch formed around the inner wall of the receptacle. A spring is affixed to the second end of the conductive rod.
It is an object of the present invention to provide an extender that provides semi-rigidity in the connection between a high-voltage source and a spark plug.
It is another object of the present invention to provide an extender that allows for slight angular misalignment between the high-voltage source and the spark plug.
It is another object of the present invention to provide an extender that does not compromise the dielectric integrity at the seal with the spark plug.
It is another object of the present invention to provide an extender that prevents high-voltage tracking.
It is another object of the present invention to provide an extender that can withstand voltage that is in excess of 36 kV.
It is still further object of the present invention to provide a high-voltage extender that avoids radial deflection of the spring/conductive connection with the spark plug.
It is a further object of the present invention provide an extender which is resistant to the corona created in the engine block.
It is still a further object of the present invention to provide an extender that is easy to manufacture, easy to install and use, and relatively inexpensive.
It is still another object of the present invention to provide an extender that can withstand high temperature conditions, such as those produced by natural gas engines.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.
The present invention is an extender for connecting a high-voltage source to a spark plug. The extender comprises a conductive member, a tube having an interior passageway in which the conductive member has at least a portion positioned in the interior passageway, and a boot affixed over an exterior of the tube. The boot is formed of an material having a rigidity less than a rigidity of the material of the tube. The boot has a first end adapted to connect with a high-voltage source and a second end adapted to be connected to the spark plug such that the conductive member is in electrical connection with the spark plug and the high-voltage source.
In the present invention, the conductive member comprises a spring. The spring is adapted to electrically connect with the high-voltage source and the spark plug. The spring extends longitudinally through an interior of the boot. The tube overlies a portion of the spring.
In an embodiment of the present invention, the boot has a first portion and a second portion that is affixed to an end of the first portion. The first portion is adapted to connect with a high-voltage source. The second portion is adapted to connect with the spark plug. The first portion has a rigidity that is less than a rigidity of the second portion. The first portion is formed of a silicone rubber material. The second portion is formed of a polyethylene terephthalate material (PET) or a liquid crystal polymer material.
The first portion has at least one annular notch formed in an inner wall thereof adjacent to an end of the first portion opposite the end adapted for connection to the high-voltage source. The second portion has an insert element fitted within the first portion. The second portion has a protrusion on the insert element that is received in the annular notch.
The tube has a flange formed adjacent one end thereof The boot has an internal shoulder formed adjacent the end that is adapted for connection to the high-voltage source. The flange abuts the interior shoulder of the boot. An O-ring is affixed within the boot adjacent the end adapted for connection to the spark plug. The O-ring is adapted to engage a terminal of the spark plug.
The foregoing Section is intended to describe, with particularity, the preferred embodiments of the present invention. It is understood that modifications to these preferred embodiments can be made within the scope of the present invention. As such, this Section should not to be construed, in any way, as limiting of the broad scope of the present invention. The present invention should only be limited by the following claims and their legal equivalents.
Referring to
In
Importantly, in the present invention, the tube 64 will have a rigidity that is greater than the rigidity of the boot 52. In particular, the boot 52 can be formed of an MS115 silicone rubber material. The tube 64 can be formed of a PET RE5329 material or a liquid crystal polymer material. As such, the tube 64 will provide rigidity to the silicone rubber material of the boot 52 for a substantial portion of the length of the boot 52. However, the outwardly extending end portion 74 of the boot 52 can be semi-flexible so as to compensate for slight angular misalignment between the high-voltage source 56 and the terminal 60 of the spark plug. The rigidity of the tube 64 will serve to protect the conductive member so as to avoid radial deflection of the conductive member.
In
As can be seen in
The terminal 124 of the high-voltage source is illustrated as received within the connector 112 at one end of the extender 100. The terminal 124 will abut an end 126 of the spring 120. A terminal 128 of a spark plug is received within the O-ring seal 108 located at end 110 of the second portion 106 of the boot 102. The spring 120 has an opposite end that will abut the end of the terminal 128. The spring 120 extends longitudinally through the interior of the boot 102 and through the interior of the tube 118. As such, the spring 120 serves to provide an electrical connection between the terminal 124 of the high-voltage source and with the terminal 128 of the spark plug.
The first portion 104 of the boot 102 has an internal shoulder 130 formed adjacent to the connector 112. An annular flange 132 is formed at the end of the tube 118 so as to securely abut with the internal shoulder 130. The second portion 106 of the boot 102 includes an insert element 136 that is received within the end 114 of the first portion 104 of boot 102. In particular, there is a shoulder formed on the second portion 106 which will abut the end 114 of the first portion 104. An annular notch 138 is formed on an inner wall of the first portion 104 of boot 102. A protrusion 140 formed on the exterior of the insert element 106 of the second portion 108 can be secured within this annular notch 138. Within the concept of the present invention, a plurality of annular notches 138 can be formed in spaced planar parallel relationship to each other. Similarly, a plurality of protrusions 104 can also be provided on the exterior surface of the insert element 136 of the second portion 106 so as to further establish a secure connection between the portions 104 and 106 of boot 102.
In
The surface between the high-voltage connection of the ignition coil and the extender utilizes O-ring seals on the extender 100 so as to seal the interface and to prevent high-voltage leakage. Because the tube is injection molded as an insert on the boot, the tube cannot move within the boot rotationally or lengthwise. This keeps the surface of the extender at the ignition coil and further prevents high-voltage leakage at this point. The materials used in the extender of the present invention are more resistant to the corona created in the engine block. During testing, the extender of the present invention achieved a longer period of use without failure compared to the extender of the prior art.
Experiments conducted with the high-voltage extender of the present invention, all embodiments, is able to withstand temperatures of up to 200° C. As such, the high-voltage extender is particularly useful in association with natural gas engines.
The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction can be made within the scope of the present claims without departing from the true spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents.
