DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 11/18/2025 has been entered.
Response to Arguments
Applicant’s arguments, see pages 5-8, with respect to the rejection(s) of claim(s) 1 and 18 under 35 U.S.C. 103 have been fully considered and are at least partially persuasive. Willi does not disclose the control valve 72, corresponding to the claimed primary fuel injector, mounted adjacent to the prechamber. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of the current amendments to the claims.
In response to applicant's argument that the references fail to show certain features of the invention, it is noted that the features upon which applicant relies (i.e., high-precision injection) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). Regarding applicant’s arguments that Willi teaches the benefits of the configuration of the prechamber with a remote injector as avoiding “large amounts of packaging space” does not teach away from the proposed modification. For a reference to be considered to teach away from a proposed modification such reference must criticize, discredit, or otherwise discourage the proposed combination. In re Fulton, 73 USPQ2d 1141 (Fed. Cir. 2004). The applicant is further advised that disclosed examples and/or preferred embodiments do not constitute a teaching away from a broader disclosure or nonpreferred embodiments, even if such nonpreferred embodiments are described as somewhat inferior. See In re Susi, 169 USPQ 423 (CCPA 1971), and In re Gurley, 31 USPQ2d 1130 (Fed. Cir. 1994). In this case, paragraph 0028 of Willi provides a preferred embodiment of the prechamber.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 1 and 18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Willi (US Patent Application Publication 2016/0160742) in view of Shinagawa (US Patent Application Publication 2009/0012698) in view of Bassett (WO 2021/173107 A1) and further in view of Zoldak (WO 2015/138987 A1).
Regarding claim 1, Willi discloses a method of initiating a diffusion combustion process for gas in a combustion chamber (20) defined by an engine cylinder (14) and a cylinder piston (18), the combustion chamber including a prechamber (50) and a spark plug (48) and a primary fuel injector (72), the prechamber and the spark plug being located at a peripheral edge of the cylinder piston [as shown in Figure 2, the prechamber and spark plug are offset from the central axis of the cylinder and piston], the cylinder piston being driven by a crankshaft (22) between bottom dead center and top dead center to perform a compression stroke [0014], the method comprising:
injecting, with the primary fuel injector, a pilot injection of primary gas directly into the prechamber using the primary fuel injector during a first phase of the compression stroke so that the pilot injection of primary gas pre-mixes with air and forms an ignitable air/gas mixture in the vicinity of the spark plug [0003, 0013, 0032, the engine system 10 is a high pressure direct injection (HPDI) gas engine system that operates by injecting a small quantity of pilot fuel during the compression stroke immediately followed by a more substantial quantity of fuel, as shown in step 302 of Figure 3 the pilot fuel is provided by valve 72];
generating a spark in the prechamber with the spark plug to ignite the ignitable air/gas mixture to generate a pre-mixed primary combustion event which results in a fuel burn and a resultant cloud of primary gas [0033, as shown in step 304 of Figure 3]; and
injecting, at a second phase of the compression stroke, using a secondary fuel injector (34), a main injection of gas directly into the resultant cloud of primary gas so that the main injection of primary gas ignites in the compression stroke to deliver a secondary combustion event [0016-0018, 0034, as shown in step 308 of Figure 3].
Willi does not disclose the gas is hydrogen gas, although Willi contemplates the use of any gaseous fuel known in the art [0020].
Shinagawa discloses a method of initiating a diffusion combustion process for hydrogen gas in a combustion chamber.
Shinagawa teaches that “hydrogen, a gaseous fuel, may be used as a fuel for an internal combustion engine. Hydrogen has a combustibility range as broad as 4-75 percent by volume and can be readily burned in an extremely lean air-fuel mixture having an air excess ratio λ that is equal to or greater than about 4. Thus, if hydrogen is used as a fuel for an internal combustion engine, power can be extracted even at an extremely lean air-fuel ratio, thereby making it possible to realize what is called a ’super lean burn operation’. In a super lean burn operation, it is possible to open a throttle valve fully, thereby reducing pumping loss and decreasing combustion temperature, which in turn leads to a reduction in cooling loss. Such a reduction in cooling loss improves engine efficiency so that the engine can be operated with an excellent fuel economy and high efficiency. Furthermore, the reduction in the combustion temperature helps to suppress NOx emission and the use of hydrogen fuel can also prevent any production of CO2 and CO. This means that hydrogen-fueled super-lean burn operation can realize a completely zero emission” [0004-0005]. Shinagawa teaches that hydrogen fuel is particularly suitable to a diffusion combustion process in which a spark plug is used to initiate combustion because this process allows hydrogen to burn more slowly, lowering peak combustion temperature and peak heat generation rate, leading to the increases in fuel economy and efficiency at high engine load described above [0097, 0100].
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to use as the primary gas for the pilot injection and the gas for the main injection disclosed by Willi, a hydrogen fuel, as disclosed by Shinagawa, in order to reduce cooling loss, improve fuel economy and efficiency especially at high engine loads, and suppress emissions of nitrogen oxides, carbon monoxide and carbon dioxide.
Willi does not disclose the combustion chamber including the prechamber. Instead, Willi discloses the spark plug having the prechamber.
Bassett discloses a spark-ignited engine with a combustion chamber including a prechamber [0008-0009, the prechamber can be integrally formed with the cylinder head when casted or include an adapter that is mechanically incorporated in the casted cylinder head, as shown in Figures 1, 2 or 3].
Bassett teaches that whether the combustion chamber includes the prechamber as in the first through third embodiments in Figures 1-3 or the spark plug includes the prechamber as in the fourth embodiment of Figure 4, the inclusion of a prechamber enables optimal combustion under conditions of low engine load, retarded combustion phasing and at cold start of the engine [0030]. Bassett teaches that use of the adapter allows a prechamber to be added to retrofit existing engines without prechambers [0009]. As shown in Figure 3, forming the prechamber integrally with the cylinder head simplifies the engine assembly by reducing the number of component parts.
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the combustion chamber disclosed by Willi to include the prechamber according to any of the first through third embodiments disclosed by Bassett because both the arrangements disclosed by Bassett and Willi enable optimal combustion under conditions of low engine load, retarded combustion phasing and at engine cold start. Furthermore, depending on how the prechamber is included in the combustion chamber, the combination can simplify assembly of the engine or allow for retrofitting existing engines with the prechamber.
Willi does not disclose the primary fuel injector mounted adjacent to the prechamber.
Zoldak discloses a primary fuel injector (including valve 106) mounted adjacent to a prechamber (108) for injecting a hydrogen gas directly into the prechamber [0037, as shown in Figure 1].
Zoldak teaches that this arrangement allows the primary fuel injector to be assembled with a spark plug igniter as “an integrated, bolt-in, singular unit” [0031], thereby, for example, simplifying engine assembly. Willi is concerned with the conversion of diesel engines to gaseous fuel operation using the technique known as high pressure direct injection (HDPI) [see Willi 0003, 0013]. Zoldak teaches that integrated injector of his invention is also suitable to operate heavy-duty compression ignition engines in a spark-ignited, direct injection mode with gaseous fuel at dilute or lean air-fuel ratios [0031].
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to substitute the primary fuel injector disclosed by Willi for the primary fuel injector disclosed by Zoldak because the injector disclosed by Zoldak would simplify engine assembly by allowing the insertion of a unitary part containing the spark plug and the injector in the engine cylinder head and because the injector in this arrangement is suitable for operating the engine in a spark-ignited, direct injection mode with hydrogen fuel at lean air-fuel ratios.
Regarding claim 18, Willi discloses a mono-fuel fuel injection system comprising:
a cylinder (14) and a cylinder piston (18) which is movable within the cylinder by means of a crankshaft (22) between bottom dead center and top dead center to perform a compression stroke [0014];
a combustion chamber (20) defined by the cylinder and a cylinder piston;
a primary fuel injector (72) for injecting a pilot injection of primary gas into a prechamber (50) forming part of the combustion chamber, the pilot injection of primary gas being mixable with air to form a primary ignitable air/gas mixture [0003, 0013, 0032, the engine system 10 is a high pressure direct injection (HPDI) gas engine system that operates by injecting a small quantity of pilot fuel during the compression stroke immediately followed by a more substantial quantity of fuel, as shown in step 302 of Figure 3 the pilot fuel is provided by valve 72];
a spark plug (48) mounted within the prechamber, the spark plug and the prechamber being mounted at a peripheral edge of the cylinder piston [as shown in Figure 2, the prechamber and spark plug are offset from the central axis of the cylinder and piston], wherein the spark plugs is configured to generate a spark for igniting the primary ignitable air/gas mixture within the prechamber which results in a fuel burn and a cloud of primary gas passing through a wall of the prechamber into the combustion chamber [0033, as shown in step 304 of Figure 3]; and
a secondary fuel injector (34) for injecting a main injection of gas directly into the cloud of primary gas within the combustion chamber [0016-0018, 0034, as shown in step 308 of Figure 3].
Willi does not disclose the gas is hydrogen gas, although Willi contemplates the use of any gaseous fuel known in the art [0020].
Shinagawa discloses a method of initiating a diffusion combustion process for hydrogen gas in a combustion chamber.
Shinagawa teaches that “hydrogen, a gaseous fuel, may be used as a fuel for an internal combustion engine. Hydrogen has a combustibility range as broad as 4-75 percent by volume and can be readily burned in an extremely lean air-fuel mixture having an air excess ratio λ that is equal to or greater than about 4. Thus, if hydrogen is used as a fuel for an internal combustion engine, power can be extracted even at an extremely lean air-fuel ratio, thereby making it possible to realize what is called a ’super lean burn operation’. In a super lean burn operation, it is possible to open a throttle valve fully, thereby reducing pumping loss and decreasing combustion temperature, which in turn leads to a reduction in cooling loss. Such a reduction in cooling loss improves engine efficiency so that the engine can be operated with an excellent fuel economy and high efficiency. Furthermore, the reduction in the combustion temperature helps to suppress NOx emission and the use of hydrogen fuel can also prevent any production of CO2 and CO. This means that hydrogen-fueled super-lean burn operation can realize a completely zero emission” [0004-0005]. Shinagawa teaches that hydrogen fuel is particularly suitable to a diffusion combustion process in which a spark plug is used to initiate combustion because this process allows hydrogen to burn more slowly, lowering peak combustion temperature and peak heat generation rate, leading to the increases in fuel economy and efficiency at high engine load described above [0097, 0100].
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to use as the primary gas for the pilot injection and the gas for the main injection disclosed by Willi, a hydrogen fuel, as disclosed by Shinagawa, in order to reduce cooling loss, improve fuel economy and efficiency especially at high engine loads, and suppress emissions of nitrogen oxides, carbon monoxide and carbon dioxide.
Willi does not disclose the prechamber forming part of the combustion chamber. Instead, Willi discloses the spark plug having the prechamber.
Bassett discloses a spark-ignited engine with a prechamber forming part of a combustion chamber [0008-0009, the prechamber can be integrally formed with the cylinder head when casted or include an adapter that is mechanically incorporated in the casted cylinder head, as shown in Figures 1, 2 or 3].
Bassett teaches that whether the combustion chamber includes the prechamber as in the first through third embodiments in Figures 1-3 or the spark plug includes the prechamber as in the fourth embodiment of Figure 4, the inclusion of a prechamber enables optimal combustion under conditions of low engine load, retarded combustion phasing and at cold start of the engine [0030]. Bassett teaches that use of the adapter allows a prechamber to be added to retrofit existing engines without prechambers [0009]. As shown in Figure 3, forming the prechamber integrally with the cylinder head simplifies the engine assembly by reducing the number of component parts.
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the combustion chamber disclosed by Willi to include the prechamber according to any of the first through third embodiments disclosed by Bassett because both the arrangements disclosed by Bassett and Willi enable optimal combustion under conditions of low engine load, retarded combustion phasing and at engine cold start. Furthermore, depending on how the prechamber is included in the combustion chamber, the combination can simplify assembly of the engine or allow for retrofitting existing engines with the prechamber.
Willi does not disclose the primary fuel injector mounted adjacent to the prechamber.
Zoldak discloses a primary fuel injector (including valve 106) mounted adjacent to a prechamber (108) for injecting a hydrogen gas directly into the prechamber [0037, as shown in Figure 1].
Zoldak teaches that this arrangement allows the primary fuel injector to be assembled with a spark plug igniter as “an integrated, bolt-in, singular unit” [0031], thereby, for example, simplifying engine assembly. Willi is concerned with the conversion of diesel engines to gaseous fuel operation using the technique known as high pressure direct injection (HDPI) [see Willi 0003, 0013]. Zoldak teaches that integrated injector of his invention is also suitable to operate heavy-duty compression ignition engines in a spark-ignited, direct injection mode with gaseous fuel at dilute or lean air-fuel ratios [0031].
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to substitute the primary fuel injector disclosed by Willi for the primary fuel injector disclosed by Zoldak because the injector disclosed by Zoldak would simplify engine assembly by allowing the insertion of a unitary part containing the spark plug and the injector in the engine cylinder head and because the injector in this arrangement is suitable for operating the engine in a spark-ignited, direct injection mode with hydrogen fuel at lean air-fuel ratios.
Claim(s) 2 is/are rejected under 35 U.S.C. 103 as being unpatentable over Willi (US Patent Application Publication 2016/0160742) in view of Shinagawa (US Patent Application Publication 2009/0012698) in view of Bassett (WO 2021/173107 A1) in view of Zoldak (WO 2015/138987 A1) and further in view of Mamiya (US Patent Number 5,413,075).
Regarding claim 2, Willi, as modified by Shinagawa, Bassett and Zoldak, discloses the method of claim 1 including pilot injection of primary hydrogen gas as discussed above, but does not disclose the injection having between 5% and 30% of a stoichiometric mixture strength of air and hydrogen gas which causes all of the air in the combustion chamber to burn.
Mamiya discloses injection of hydrogen gas having between 5% and 30% of a stoichiometric mixture strength (Col. 7, lines 43-65) (Col. 11, lines 44-56). Mamiya does not explicitly disclose all of the air in the combustion chamber burning under this condition, but this is an intended use or result of the recited limitation. A recitation of the intended use of the claimed invention must result in a structural difference between the claimed invention and the prior art in order to patentably distinguish the claimed invention from the prior art. If the prior art structure is capable of performing the intended use, then it meets the claim. See MPEP 2111.02 (II).
Mamiya teaches that injecting hydrogen gas at a leaner mixture strength than stoichiometric when the accelerator opening is fixed and the engine load is constant can be used to suppress NOx production (Col. 11, lines 57-63).
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the mixture strength of the hydrogen gas pilot injection disclosed by Willi, as modified by Shinagawa and Bassett, under fixed accelerator and load conditions disclosed by Mamiya in order to suppress NOx pollutant production.
Claim(s) 3 is/are rejected under 35 U.S.C. 103 as being unpatentable over Willi (US Patent Application Publication 2016/0160742) in view of Shinagawa (US Patent Application Publication 2009/0012698) in view of Bassett (WO 2021/173107 A1) in view of Zoldak (WO 2015/138987 A1) and further in view of Kavuri (US Patent Number 11,415,083).
Regarding claim 3, Willi, as modified by Shinagawa, Bassett and Zoldak, discloses the method of claim 1 as discussed above but does not explicitly disclose injecting the pilot injection of primary hydrogen gas at a crankshaft angle of between 60 degrees and 10 degrees before the cylinder piston.
Kavuri discloses an engine systems and methods comprising injecting hydrogen gas at a crankshaft angle of between 60 degrees and 10 degrees before the cylinder piston is at TDC (Col. 6, lines 16-32).
Kavuri teaches that injecting hydrogen gas at the above described timing is one of several features that may help to increase efficiency and/or output of the engine and/or reduce heat generation or engine emissions (Col. 5, lines 36-39).
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to set the crankshaft angle at which the pilot hydrogen gas disclosed by Willi is injected because there is a limited range of crankshaft angles at which the injection may occur and it would be obvious to try an angle in the limited range of available angles and because performing the injection in this range has been known in the art to possible increase efficiency or output of the engine or reduce heat generation or engine emissions.
Claim(s) 4 is/are rejected under 35 U.S.C. 103 as being unpatentable over Willi (US Patent Application Publication 2016/0160742) in view of Shinagawa (US Patent Application Publication 2009/0012698) in view of Bassett (WO 2021/173107 A1) in view of Zoldak (WO 2015/138987 A1) and further in view of Seboldt (DE 10 2020 204 828 A1).
Regarding claim 4, Willi, as modified by Shinagawa, Bassett and Zoldak, discloses the method of claim 1 as discussed above but does not disclose wherein for the pilot injection of primary hydrogen gas and the main injection of hydrogen gas a cone angle of the hydrogen jet is less than or equal to 90 degrees.
Seboldt discloses limiting injection of hydrogen gas into a combustion chamber so that the cone angle of the hydrogen jet is less than or equal to 90 degrees [0017, 0020, 0024].
Seboldt teaches that narrowing the cone angle of the hydrogen jet creates a particularly homogeneous fuel distribution in the combustion chamber because the jet penetrates deeper into the interior of the chamber as compared to when the jet is not narrow [0017]. The resulting fuel is distributed near the piston instead of remaining near the injector outlet opening [0017, 0034].
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to limit the cone angle of the injector outlet opening disclosed by Willi, as modified by Shinagawa and Bassett, to less than or equal to 90 degrees as taught by Seboldt so that the hydrogen jet penetrates to the necessary distance in the combustion chamber that achieves a uniformly distributed fuel-air mixture by ensuring the hydrogen gas does not remain in the vicinity of the injector outlet opening.
Claim(s) 5-7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Willi (US Patent Application Publication 2016/0160742) in view of Shinagawa (US Patent Application Publication 2009/0012698) in view of Bassett (WO 2021/173107 A1) in view of Zoldak (WO 2015/138987 A1) and further in view of Kitagawa (JP 2000-120482 A).
Regarding claims 5-6, Willi, as modified by Shinagawa, Bassett and Zoldak, discloses the method of claim 1 as discussed above, but does not explicitly disclose wherein up to 90% of the fuel burn of the primary combustion event occurs over a crankshaft angle range of 10°. Shinagawa illustrates in Figure 21 that the spark plug ignites the pilot injected gas mixed with air after it is injected but before the main injection. The pilot injection is combusted by the earliest ignition [0207]. Shinagawa teaches that the ignition timing is set before compression TDC, but does not specify the exact crank angle of the ignition timing [0090].
Kitagawa teaches that the ignition timing at a low load of 4000 rpm is on the advanced side of -20 to -30 degrees from the top dead center of the piston [0011]. This advancing of ignition timing increases engine output without increasing fuel consumption [0011].
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to set the ignition timing disclosed by Willi, as modified by Shinagawa, to the ignition timing disclosed by Kitagawa, because the timing disclosed by Kitagawa has been known to be used at low loads to increase engine output without increasing fuel consumption. In this case, over a crankshaft angle range of 10° during the duration of the fuel burn of the primary combustion event, less than 90% of combustion is completed and the spark is generated in a range up to 30° prior to the crank angle at which the main injection of hydrogen gas is injected.
Regarding claim 7, Shinagawa further discloses generating a spark for the main injection at a crankshaft angle of no more than 10° after 90% of the fuel burn of the primary combustion event has occurred [0173, 0207]. It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to adjust the spark timing disclosed by Willi to the spark timing disclosed by Shinagawa in order to use a timing appropriate when the gaseous fuel is hydrogen and to achieve the advantages discussed in reference to claim 1 above.
Claim(s) 12-13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Willi (US Patent Application Publication 2016/0160742) in view of Shinagawa (US Patent Application Publication 2009/0012698) in view of Bassett (WO 2021/173107 A1) in view of Zoldak (WO 2015/138987 A1) and further in view of Kitagawa (JP 2000-120482 A).
Regarding claims 12-13, Willi, as modified by Shinagawa, Bassett and Zoldak, discloses the method of claim 1 as discussed above but does not disclose injecting the pilot injection of primary hydrogen gas with the primary fuel injector at a pressure below 50 bar, or injecting the main injection of hydrogen gas from the secondary fuel injector at a different pressure range from the pilot injection of primary hydrogen gas from the primary fuel injector.
Marko discloses a feed and ignition device for a gas engine comprising an active prechamber (30) that comprises a primary fuel injector (38), and a method comprising injecting a pilot injection of primary hydrogen gas directly into the prechamber with the primary fuel injector [0030, 0049, 0064], injecting the pilot injection of primary hydrogen gas with the primary fuel injector at a pressure below 50 bar [0048], and injecting the main injection of hydrogen gas from a secondary fuel injector (20) at a different pressure range from the pilot injection of hydrogen gas from the second prechamber injector [0053].
Marko teaches that having the pressure for injecting the primary hydrogen gas in the prechamber significantly lower than the pressure for injecting in the combustion chamber allows for a simpler design and a more cost-effective layout for the prechamber injector [0064]. Marko teaches that early, pilot injection of hydrogen gas in the prechamber ahead of the main injection improves functioning of the spark ignition system [0064].
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to combine as disclosed by Marko the primary fuel injector operating at a lower pressure than the injector disclosed by Willi, as modified by Shinagawa and Bassett, in order to improve spark ignition in a cost-effective manner that does not make the fuel system layout more complex.
Claim(s) 19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Willi (US Patent Application Publication 2016/0160742) in view of Shinagawa (US Patent Application Publication 2009/0012698) in view of Bassett (WO 2021/173107 A1) in view of Zoldak (WO 2015/138987 A1) and further in view of Snuis (GB 2555116 A).
Regarding claim 19, Willi, as modified by Shinagawa, Bassett and Zoldak, discloses the system of claim 18 as discussed above but does not disclose wherein a surface of the cylinder piston defines, together with a ceiling of the cylinder, a squish region radially outward of a piston bowl of the cylinder piston, and wherein the surface is provided with at least one recess to direct the injected pilot of primary hydrogen gas and the main injection of hydrogen gas into the piston bowl.
Snuis discloses a piston (2) for a spark ignited gas engine wherein a surface (32) of the cylinder piston defines, together with a ceiling (7’) of a cylinder housing the piston, a squish region radially outward of the piston bowl (27), and wherein the surface is provided with at least one recess (25) to direct the injected fuel into the piston bowl [page 7, lines 19-21].
Snuis teaches that the piston bowl shape generates a voluminous squish flow resulting in a turbulent swirling flow pattern that aids in the combustion of the fuel [page 7, lines 26-29].
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the shape of the piston disclosed by Willi, as modified by Shinagawa and Bassett, to include the bowl shape disclosed by Snuis because this bowl shape has been known to aid in the combustion of fuel in a spark-ignited, gaseous fueled engine.
Conclusion
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/JOSHUA CAMPBELL/
Examiner, Art Unit 3747
/LOGAN M KRAFT/ Supervisory Patent Examiner, Art Unit 3747