Multi-Electrode Spark Plug
20180123322 ยท 2018-05-03
Inventors
Cpc classification
H01T13/20
ELECTRICITY
F02P15/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
H01T13/20
ELECTRICITY
Abstract
A multi-electrode spark plug having a large spark target volume is disclosed. The spark plugs have a plurality of ground electrode rods which extend from the base of the spark plug and are twisted around center electrode to provide a plurality of substantially equidistant spark points relative to the center electrode. The spark points are formed in parallel and around the elongated axis of the spark plug. This configuration enables the spark to be created where the localized concentration of fuel to air is richer, such as that which may exist when the engine is operating with lower revolutions per minute. Test results indicate that automobiles equipped with the multi-electrode spark plugs exhibit improved fuel economy, and substantially reduced emissions and air pollution.
Claims
1-20. (canceled)
21. A spark plug comprising: an insulating body having an open bore; a tubular conductive shell surrounding at least a portion of the insulating body; a cylindrical center electrode positioned within the bore of the insulating body, the center electrode having a central longitudinal axis, the center electrode protruding from the insulating body forming a terminal end portion adapted to act as a spark generating portion; and, a plurality of ground electrodes surrounding the center, each ground electrode having a base end coupled to the conductive shell and an elongated upper portion that extends from the base end to a distal end that is longitudinally spaced from the base end and that also curves around the central longitudinal axis to form a generally curved path and provide an elongated inner surface having a radial spark gap distance from the spark generating portion of the center electrode.
22. The spark plug of claim 21, wherein the plurality of ground electrodes further comprises a first set of ground electrodes and a second set of ground electrodes, the first set of ground electrodes having a first radial spark distance, the second set of ground electrodes having a second radial spark distance, the first radial spark distance differing the from the second spark distance.
23. The spark plug of claim 22, wherein the first set of electrodes comprises bi-metal electrodes configured to move radially away from the center electrode with increasing temperature.
24. The spark plug of claim 21, wherein the generally curved path comprises a helix formed about the longitudinal axis of the center electrode.
25. The spark plug of claim 21, wherein the radial spark gap is in the range of approximately 1.7 millimeters to approximately 4.75 millimeters.
26. The spark plug of claim 21, wherein the spark generating portion of the center electrode and the elongated upper portions of the ground electrodes form a three-dimensional spark target volume.
27. The spark plug of claim 26, wherein the spark target volume is approximately 100 cubic millimeters.
28. The spark plug of claim 21, wherein the spark target volume comprises a generally open volume adopted for allowing free propagation of fuel burn.
29. The spark plug of claim 21, wherein one of the plurality of ground electrodes comprises a conductor having a Positive Temperature Coefficient which increases the electrical resistance of said conductor having the Positive Temperature Coefficient with increasing temperature.
30. The spark plug of claim 21, wherein the plurality of ground electrodes comprises six ground electrodes.
31. The spark plug of claim 21, wherein the elongated upper portion of each ground electrodes partially overlaps the base end of an adjacent ground electrode when viewed along the central longitudinal axis.
32. A spark plug comprising: an insulating body having an open bore; a tubular conductive shell surrounding at least a portion of the insulating body; a cylindrical center electrode positioned within the bore of the insulating body, the center electrode having a central longitudinal axis, the center electrode protruding from the insulating body forming a terminal end portion adapted to act as a spark generating portion; and, a plurality of cylindrical ground electrodes surrounding the center electrode, each ground electrode having a base end coupled to the conductive shell and an elongated upper portion that extends from the base end to a distal end that is longitudinally spaced from the base and that also curves around the central longitudinal axis to form a generally curved path and provide an elongated inner surface having a radial spark gap distance from the spark generating portion of the center electrode, the plurality of ground electrodes having a first set of ground electrodes and a second set of ground electrodes, the first set of ground electrodes having a first radial spark distance, the second set of ground electrodes having a second radial spark distance, the first radial spark distance differing the from the second spark distance.
33. The spark plug of claim 32, wherein the first set of electrodes comprises bi-metal electrodes configured to move radially away from the center electrode with increasing temperature.
34. The spark plug of claim 32, wherein the spark target volume comprises a generally open volume adopted for allowing free propagation of fuel burn.
35. The spark plug of claim 32, wherein one of the plurality of ground electrodes comprises a conductor having a Positive Temperature Coefficient which increases the electrical resistance with increasing temperature.
36. The spark plug of claim 32, wherein the plurality of ground electrodes comprises six ground electrodes.
37. A spark plug comprising: a cylindrical center electrode having a central longitudinal axis, the center electrode forming a terminal end portion adapted to act as a spark generating portion; and, a plurality of ground electrodes surrounding the center electrode, each ground electrode having a base and an elongated upper portion that extends from the base end to a distal end that is longitudinally spaced from the base end and that also curves around the central longitudinal axis to form a generally curved path and provide an elongated inner surface having a radial spark gap distance from the center electrode.
38. The spark plug of claim 37, wherein the spark target volume is approximately 100 cubic millimeters.
39. The spark plug of claim 37, wherein the spark target volume comprises a generally open volume adopted for allowing free propagation of fuel burn.
40. The spark plug of claim 37, wherein the elongated upper portion of each ground electrode partially overlaps the base end of an adjacent ground electrode when viewed along the central longitudinal axis.
Description
DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0058] In one or more embodiments, a spark plug comprises multiple ground electrodes surrounding a center electrode forming a large, three-dimensional spark target volume. The ground electrodes extend from the base of the spark plug and are twisted around the center electrode to provide a plurality of substantially equidistant spark points relative to the center electrode. The spark points are formed in parallel and around the elongated axis of the spark plug. This configuration enables a spark to be created where the localized concentration of fuel to air is richer.
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[0061] The operation of the Intelligent spark plug 10 is based on a theory, confirmed by experimental observation, that the hydrocarbons in a richer fuel/air mixture provide an electrical path of least resistance for the spark. It is believed that new Intelligent spark plug 10 provides much greater efficiency and a more thorough burn at low revolutions per minute (RPMs) because its configuration permits the spark to uniquely hunt for the richest zone of the fuel/air mixture. For engines operating below about 2,000 RPM, the fuel/air ratio is less uniform (i.e., homogenous) that at higher speeds. In such a case, the fuel/air mixture may be richer on one side of the cylinder than on the other. The new Intelligent spark plug 10 may help the most, therefore, for low RPMs, stop and go driving. It may also help increase efficiencies during the RPM drops associated with automatic transmission shifting.
[0062] As shown in
[0063] In one or more embodiments, the spark generating portion 52 of the center electrode 50 and the upper portions 34 of the ground electrodes 30 form a three-dimensional spark target volume 74 (See
[0064] As seen in
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[0075] Several tests were made comparing the performance of automobiles using conventional and Intelligent Spark plugs. The tests included comparing pollution emissions, fuel economy, and engine performance for several automobiles. Embodiments of the Intelligent spark plug may reduce the emission of air pollution from internal combustion engines.
[0076] Cars, scooters, motorbikes, electric power generators, and power tools are very useful but come with a price in the form of emissions and air pollution. In 1967 the State of California created the California Air Resources Board to fight car air pollution. In 1970, the United States Federal government created the United States Environmental Protection Agency (EPA). Today most of the countries around the world regulate car emission to be measured and to meet specified values. Reducing or eliminating pollution is important for reducing the effects of climate change, as some believe that climate change may force 1 out of every 13 species to extinction on average if left unchecked.
[0077] Many countries have adopted anti-pollution measures. In Germany since 2010, Berlin has an ecological area in the city center where only vehicles with appropriate stickers indicating low emission may enter. In Britain, a congestion toll was implemented in London city center since 2003. In Greece since 1982, an alternating traffic system is employed in Athens. In Italy, since the 1990s, an alternating traffic system in Rome and restricted traffic areas in historic center are employed. In Portugal, there are some restricted traffic areas in the historic town center of Lisbon for vehicles manufactured before 2000. In Scandinavia, there is a congestion toll in Sweden, bike paths in Denmark, and congestion tolls and electric cars in Norway. In Paris, the French capital on Mar. 23, 2015 adopted an emergency traffic-limiting measure to reduce pollution in the Paris sky, using an alternating traffic system which stops one in every two cars, scooters, or motorcycles entering the capital city.
[0078] Internal combustion engines emit CO.sub.2 (Carbon Dioxide) which is not directly harmful, but produces global warming, HC (unburned Hydrocarbons) which is a major contributor to smog and is linked to asthma, liver disease, lung disease, and cancer, CO (Carbon Monoxide) which reduces the blood's ability to carry oxygen and overexposure is fatal, and NO (Nitrogen Oxides) which is a precursor to smog and acid rain and may destroy resistance to respiratory infection.
[0079] Several tests were performed on multiple cars to investigate the performance of automobiles equipped with embodiments of the Intelligent spark plug. In a first test, a pollution reduction evaluation test was performed on a 2002 CHRYSLER CONCORDE 2.7 Liter V6 engine at a California Smog Check Station. The same car was tested twice. In one test, conventional spark plugs were installed, and in the second test, Intelligent spark plugs were installed.
[0080] Tables I and II below present the emission test results for the automobile installed with conventional spark plugs and Intelligent spark plugs respectively.
TABLE-US-00001 TABLE I Emission Results With Market Leading Spark Plugs % % HC CO NO Test RPM CO2 O2 (PPM){grave over ()} (%) (PPM) M1: 15 MPH 1628 15.0 0.2 50 0.09 387 M2: 25 MPH 1664 15.0 0.1 4 0.00 49
TABLE-US-00002 TABLE II Emission Results with Intelligent Spark Plugs % % HC CO NO Test RPM CO2 O2 (PPM){grave over ()} (%) (PPM) M1: 15 MPH 1684 14.9 0.1 6 0.00 52 M2: 25 MPH 1669 15.0 0.1 0 0.00 9
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[0082] In summary, embodiments described herein have been shown to outperform conventional spark plugs with respect to HC emission (>800% improvement), CO (>900% improvement), and NO (>700% improvement). The average improvement in emissions is 8 times better. The typical differences in pollution emission between differing brands of conventional spark plugs may be between 5% and 10%.
[0083] A second test was performed to determine the increase in fuel efficiency for engines employing embodiments of the spark plugs installed in a 2014 TOYOTA CAMRY 2.5 Liter, 4 cylinder gasoline engine. This car has an EPA Highway rating of 35 miles per gallon (MPG) at an average speed of 48.3 MPH and a top speed of 60 MPH. The EPA City rating for this car is 25 MPG at an average speed of 21.2 MPH and a top speed of 56.7 MPH. The combined EPA rating is 28 MPG. A user's average is 27.3 MPG.
[0084] The EPA tests for fuel economy requires a vehicle to run through a series of pre-determined driving routines referred to as schedules or cycles that specify the vehicle speed for each point in time during the tests.
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[0086] A driving test was performed with the 2014 TOYOTA CAMRY to determine the fuel efficiency as a result of using embodiments of the Intelligent spark plugs described herein. The fuel consumption was determined by starting with the fuel consumption figures for a particular vehicle, a 2014 TOYOTA CAMRY, by driving this vehicle over a test route while it was equipped with conventional spark plugs and again when the vehicle was equipped with the Intelligent spark plugs. The car equipped with conventional spark plugs exhibited a fuel economy of 27.5 MPG. In contrast, the car equipped with the Intelligent spark plugs exhibited a significantly better fuel consumption of 34.7 MPG.
[0087] Specifically, the car traveled 2,269 miles through California, Nevada, and Arizona with highway speeds ranging from 75 to 85 MPH. When the conventional spark plugs were tested, the average reading was 27.5 MPG, which is consistent with the EPA rating. When the Intelligent spark plug was employed, the average gas fuel efficient was 34.7 MPG, for a 26% increase in fuel economy.
[0088] A Dynamometer test measuring power was also performed on the same 2014 TOYOTA CAMRY, with the best result out of 3 runs were evaluated. The dyno measurements show horsepower (hp) produced by the same vehicle, over a range of speeds (MPH), with conventional plugs and with the Intelligent spark plugs, the overall graphs and maximum power readings showing that the vehicle exhibits similar maximum horsepower readings with the Intelligent spark plugs (that provided increase fuel consumption in terms of MPG) as compared with the conventional spark plugs.
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[0090] The generated torque was also measured on the 2014 TOYOTA CAMRY. The dyno measurements that show torque produced by the same vehicle, over a range of speeds, with conventional plugs and with the Intelligent spark plugs, the overall graphs and torque readings showing that the vehicle exhibits a faster increased rate for torque with the Intelligent spark plugs (that provided increase fuel consumption in terms of MPG) as compared with the conventional spark plugs.
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[0092] Hence, the first and second tests performed on difference cars suggest that cars outfitted with the Intelligent spark plug may exhibit 8 times less harmful emissions, better fuel economy, no reduction in power, greater torque, and faster, more peppy response. The overall improvements are shown in terms of less harmful emission, better fuel consumption, no power reduction, higher torque, and faster response.
[0093] Moreover, it may be easier to mandate the replacement of existing spark plugs to reduce pollution. In conclusion, the Intelligent spark plugs may deliver cleaner air, reducing the rate of global warming, fuel savings, and better a less expensive healthcare.
[0094] A third test was performed with two identical 2016 TOYOTA RAV4 automobiles with 2.5 L engines. Conventional Iridium spark plugs were employed in the first car, and Intelligent spark plugs were employed in the second car. The cars were both driven 193.9 miles after two hours and 33 minutes at an average speed of 76 MPH.
[0095] The car equipped with the OEM Iridium spark plugs recorded 27.4 MPG. The car equipped with Intelligent spark plugs recorded 30.2 MPG. Based on the trip computer, the car equipped with the Intelligent spark plug exhibited a 10.2% fuel consumption improvement. The fuel economy based on the mileage driven and the amount of gasoline required to refill the tanks showed a 9.2% increase in fuel economy for the automobile equipped with the Intelligent spark plug.
[0096] The TOYOTA RAV4 car equipped with the Intelligent spark plugs also underwent a smog check. The results of the smog check are present in Table III below.
TABLE-US-00003 TABLE III Emission Report for the 2016 TOYOTA RAV4 with Intelligent spark plugs % % HC CO NO Test RPM CO2 O2 (PPM){grave over ()} (%) (PPM) M1: 15 MPH 1388 14.8 0.2 0 0.00 0 M2: 25 MPH 1637 14.8 0.0 0 0.00 0
[0097] The smog test revealed that the TOYOTA RAV4 car equipped with Intelligent spark plugs exhibited zero emission for Hydrocarbons. Carbon Monoxide and Nitrogen Oxides.
[0098] In summary, preliminary tests indicate that automobiles equipped with embodiments of the Intelligent spark may exhibit greater fuel efficiency, and reduced or eliminated emissions of Hydrocarbons, Carbon Monoxide, and Nitrogen Oxides.
[0099] There are many possible alternatives or improvements. For example, the center electrode 50 could have a diamond pattern, or otherwise be knurled, to provide enhanced spark jump opportunities. Along the same lines, the spiraling electrodes 30 could also be provide with a similar diamond pattern.
[0100] It may also be possible to use a bi-metal arrangement so that the spiraling ground electrodes 50, when exposed to the heat of combustion, expand farther apart than initially permitted by the threaded hole that receives the base of the spark plug. This would allow for an increased gap between the center electrode and the spiraling electrodes which may further increase efficiency.
[0101] The Intelligent spark plug was also tested on power tools (e.g., leaf blower, gas electrical power generator) equipped with two-stroke and four-stroke gas engines. The emissions of these engines did reduce substantially but it was also observed, especially on two-stroke engines, that the spark gaps of the 6 electrodes need to be reduced for a consistent cold start. After engine was warm, replacing the spark plug with one with the 6 electrodes arranged to a bigger spark gap improved even better the engine functionality and reduced even more the emissions. This observation led to the creation of a new version of the Intelligent spark plug specially designed for engines equipped with sources of high voltage unable to cover big spark gaps at cold start.
[0102] The Low Voltage Intelligent spark plug has one of the electrodes built from bi-metal material or PTC (Positive Temperature Coefficient) material. This new electrode will create a smaller spark gap when the engine is at cold start. After engine start functioning the heat created inside the combustion chamber will make the new electrode move away from the center electrode beyond the rest of the bigger gap electrodes (bi-metal version) or increase the impedance path of that electrode (PTC version), and let the rest of the bigger gap electrodes do their job of hunting the fuel rich areas and ignite in that place for a fast and efficient combustion.
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[0105] Another alternative embodiment is a Variable Gap Intelligent Spark Plug with one fixed ground electrode that is closer to the center electrode (to help the cold start on low voltages) and a number of 4, 5, 6 or more electrodes, all at a greater distance (sparking gap) from the center electrode. One or more embodiments further comprise an additional fixed ground electrode positioned closer to the center electrode than the plurality of ground electrodes.
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[0107] It is believed that once the engine starts running, the compression and the heat applied to the fuel-air mixture make the sparking gap difference between the ground electrodes less relevant and the other 5 electrodes with bigger spark gap will still work on hunting fuel richer areas due to low impedance path of these areas. During testing at room temperature, as expected, the spark discharge occurred all the time between the center electrode and the closer ground electrode when no propane gas was present. However, once the propane was introduced into the area with the other 5 ground electrodes with bigger spark gap, the spark discharge will move from the initial ground electrode with smaller sparking gap to whatever electrode with bigger sparking gap is closer to the propane gas.
[0108] The demand for spark plugs is projected to grow significantly for the foreseeable future. As of 2010, there are over one billion motor vehicles in use in the world, excluding off-road vehicles and snowmobiles, scooters and motorbikes, motorboats, and small tools and construction equipment, which also require spark plugs to function. U.S. researchers estimate that size of the world's fleets will double, reaching two billion motor vehicles by 2020. Big growth is expected from developing economies of the BRICS (i.e., Brazil, Russia, India, China, and South Africa). China, the fastest growing large economy is also the fastest growing market for automobiles, now with over 100 million vehicles on the road. The USA currently has the most number of vehicles, with over 250 million vehicles, and China is expected to overtake USA as the largest automobile market on the planet.
[0109] In 2015, the market reached some 1.5 billion vehicles. Two-thirds or some one billion vehicles are powered by gas engines, and one-third are powered by diesel, hydrogen, or electricity. Each gas engine uses four to twelve spark plugs. Considering an average of 5 spark plugs for today's one billion gas engines, there are about five billion spark plugs in use currently.
[0110] By 2020, two billion motor vehicles are expected to be on the road, increasing at a rate of 100,000,000 vehicles per year. Gas engines accounts for two-thirds of the total of some 65,000,000 per year and need an average of five spark plugs. This means that there is a need of more than 300,000,000 spark plugs just for new gas engines. There is also an additional spark plug need for replacement and service, scooters and motorbikes, off-road vehicles and snowmobiles, motorboats, and small tools and construction equipment.
[0111] The cost of manufacturing a spark plug is approximately US$0.50 in volume. The wholesale prices range from US$1-US$4 per unit. One company's starting prices are US$0.96 per unit. The retail price ranges from US$2.50 up to US$30 for premium plugs, giving a margin of in excess of US$0.50 per unit. Hence, 300,000,000 spark plugs can generate a total margin of at least US$150,000,000 per year. Replacement spark plugs can generate a lot more revenue, especially if mandated for reducing pollution. There are currently five major spark plug manufacturers: BOSCH, NGK, CHAMPION, DENSO, and AUTOLITE.
[0112] Although the invention has been discussed with reference to specific embodiments, it is apparent and should be understood that the concept can be otherwise embodied to achieve the advantages discussed. The preferred embodiments above have been described primarily as spark plugs having multiple ground electrodes forming a large spark target volume. In this regard, the foregoing description of the spark plugs is presented for purposes of illustration and description.
[0113] Furthermore, the description is not intended to limit the invention to the form disclosed herein. Accordingly, variants and modifications consistent with the following teachings, skill, and knowledge of the relevant art, are within the scope of the present invention. The concepts discussed herein may be applied to other spark creation devices or for applications including internal combustion engines for automobiles, trucks, power tools, and other vehicles as well for other types of engines. The embodiments described herein are further intended to explain modes known for practicing the invention disclosed herewith and to enable others skilled in the art to utilize the invention in equivalent, or alternative embodiments and with various modifications considered necessary by the particular application(s) or use(s) of the present invention.