DETAILED ACTION
Notice to Applicant
In the amendment dated 2026-08-18, the following has occurred: Claims 1, 5, 8, and 9 have been amended; Claims 2-3 and 6-7 have been canceled; Claims 10-21 have been added.
Claims 1, 4-5, and 8-21 are pending and are examined herein. This is a Final Rejection.
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claim Rejections - 35 USC § 103
Claims 1, 4, 8, 10, 12, 14, 16, and 18-20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Masui (JP 2014-120386 to Masui). Alternatively, they are rejected as obvious under 35 U.S.C. 103 as being unpatentable over Masui in view of Suda (US 2005/0006487 to Suda et al.).
Regarding Claim 1, Masui teaches:
a cooling system for a fuel cell 10 with a refrigerant flow channel, a radiator 50 configured to radiate heat from the refrigerant that has passed through the fuel cell, a bypass flow channel LB configured to bypass the radiator, and a thermostat valve 40 configured to select a flow path for the refrigerant between the radiator and the bypass flow channel according to a temperature of the refrigerant (Fig. 1, ¶ 0020-0021)
a temperature sensor 30 configured to measure a temperature of the refrigerant that has passed through the fuel cell as part of the refrigerant loop (Fig. 1, ¶ 0022)
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a controller configured to control the temperature of the fuel cell stack, which requires determining a target temperature and comparing it to the sensed outlet temperature (¶ 0048, 0057-0059)
an embodiment in which the controller determines a target stack outlet coolant temperature and compares it to a target temperature (¶ 0061), determines that the fuel cell temperature should be raised or lowered to meet the target temperature (¶ 0066-0067, 0071), and setting the flow rate of the coolant higher or lower to supply or remove the required quantity of heat (¶ 0071-0073)
Masui talks about a specific example, such as warm-up, but also either directly teaches or implies that target temperatures can be higher or lower, and the coolant flow rate can be increased, or decreased, to supply or remove heat from the fuel cell. Masui also changes the flow rate of the coolant, including increasing the flow rate above the basic target flow in order to reduce hunting. This change in the flow rate inherently “changes the temperature hysteresis characteristic” of the valve, within the broadest reasonable interpretation of the claims, because it has all the essential elements of such a change as described by the instant specification. That is, Masui has a circulation pump in series and downstream of the thermostat valve, so the changing the flow rate at the pump changes the flow rate through the valve, substantially similar to the instant invention. Masui adjusts the flow based on the fuel cell coolant temperatures, reducing flow when the radiator water is cold relative to the stack coolant (Krad) and while the coolant temperature is falling (KdTfc) to suppress the temperature drop caused by cold radiator coolant entering as the valve opens. Separately, it increases flow as the coolant temperature rises above the control target temperature (Tg), and reduces it below the target temperature. The instant application teaches that changing the flow in this manner produces a change in the claimed “hysteresis characteristic” and so such a change would be expected in Masui.
Additionally, Suda is cited for teaching a deliberate correction of wax-thermostat hysteresis in cooling and heating of an engine, including a radiator, valve, and pump in a coolant system that mirrors that taught in Masui and in the instant application (abstract, ¶ 0026-0029). Suda teaches an electrical heater that heats the wax valve, changing its hysteresis characteristic, in response to a controller’s determination to change the fuel cell temperature via manipulating the coolant. It teaches, in other words, that hysteresis and reversal delay in a wax thermostat were recognized control errors that could be fixed by a controller applying direction-dependent correction to the wax thermostat. Masui teaches this through radiator change (i.e. fan control) and through coolant flow rate. It would have been obvious based on the prior art of record to change the hysteresis characteristic of the valve in order to improve heating and cooling of the fuel cell of Masui, depending on whether the fuel cell target temperature was higher or lower than the sensed outlet temperature.
Regarding Claim 4, Masui teaches:
changing the coolant temperature via the radiator fan (¶ 0064, etc.)
Additionally, Suda is cited for teaching a deliberate correction of wax-thermostat hysteresis in cooling and heating of an engine, including a radiator, valve, and pump in a coolant system that mirrors that taught in Masui and in the instant application (abstract, ¶ 0026-0029). Suda teaches an electrical heater that heats the wax valve, changing its hysteresis characteristic, in response to a controller’s determination to change the fuel cell temperature via manipulating the coolant. It teaches, in other words, that hysteresis and reversal delay in a wax thermostat were recognized control errors that could be fixed by a controller applying direction-dependent correction to the wax thermostat. Masui teaches this through radiator change (i.e. fan control) and through coolant flow rate. It would have been obvious based on the prior art of record to change the hysteresis characteristic of the valve in order to improve heating and cooling of the fuel cell of Masui, depending on whether the fuel cell target temperature was higher or lower than the sensed outlet temperature.
Regarding Claim 8, Masui teaches:
a cooling system for a fuel cell 10 with a refrigerant flow channel, a radiator 50 configured to radiate heat from the refrigerant that has passed through the fuel cell, a bypass flow channel LB configured to bypass the radiator, and a thermostat valve 40 configured to select a flow path for the refrigerant between the radiator and the bypass flow channel according to a temperature of the refrigerant (Fig. 1, ¶ 0020-0021)
a temperature sensor 30 configured to measure a temperature of the refrigerant that has passed through the fuel cell as part of the refrigerant loop (Fig. 1, ¶ 0022)
a controller with a processor configured to control the temperature of the fuel cell stack, which requires determining a target temperature and comparing it to the sensed outlet temperature (¶ 0048, 0057-0059)
an embodiment in which the controller determines a target stack outlet coolant temperature and compares it to a target temperature (¶ 0061), determines that the fuel cell temperature should be raised or lowered to meet the target temperature (¶ 0066-0067, 0071), and setting the flow rate of the coolant higher or lower to supply or remove the required quantity of heat (¶ 0071-0073)
Masui talks about a specific example, such as warm-up, but also either directly teaches or implies that target temperatures can be higher or lower, and the coolant flow rate can be increased, or decreased, to supply or remove heat from the fuel cell. Masui also changes the flow rate of the coolant, including increasing the flow rate above the basic target flow in order to reduce hunting. This change in the flow rate inherently “changes the temperature hysteresis characteristic” of the valve, within the broadest reasonable interpretation of the claims, because it has all the essential elements of such a change as described by the instant specification. That is, Masui has a circulation pump in series and downstream of the thermostat valve, so the changing the flow rate at the pump changes the flow rate through the valve, substantially similar to the instant invention. Masui adjusts the flow based on the fuel cell coolant temperatures, reducing flow when the radiator water is cold relative to the stack coolant (Krad) and while the coolant temperature is falling (KdTfc) to suppress the temperature drop caused by cold radiator coolant entering as the valve opens. Separately, it increases flow as the coolant temperature rises above the control target temperature (Tg), and reduces it below the target temperature. The instant application teaches that changing the flow in this manner produces a change in the claimed “hysteresis characteristic” and so such a change would be expected in Masui.
Additionally, Suda is cited for teaching a deliberate correction of wax-thermostat hysteresis in cooling and heating of an engine, including a radiator, valve, and pump in a coolant system that mirrors that taught in Masui and in the instant application (abstract, ¶ 0026-0029). Suda teaches an electrical heater that heats the wax valve, changing its hysteresis characteristic, in response to a controller’s determination to change the fuel cell temperature via manipulating the coolant. It teaches, in other words, that hysteresis and reversal delay in a wax thermostat were recognized control errors that could be fixed by a controller applying direction-dependent correction to the wax thermostat. Masui teaches this through radiator change (i.e. fan control) and through coolant flow rate. It would have been obvious based on the prior art of record to change the hysteresis characteristic of the valve in order to improve heating and cooling of the fuel cell of Masui, depending on whether the fuel cell target temperature was higher or lower than the sensed outlet temperature.
Regarding Claims 10 and 12, Masui teaches:
changing the radiator capacity settings and changing the flow rate to effect the temperature changes as needed (¶ 0064)
Regarding Claims 14 and 16, Masui does not teach:
a flow rate regulation valve
Regarding Claims 18 and 19, Masui teaches:
changing the flow rate in substantially the same manner as the instant invention
Masui has a circulation pump in series and downstream of the thermostat valve, so the changing the flow rate at the pump changes the flow rate through the valve, substantially similar to the instant invention. Masui adjusts the flow based on the fuel cell coolant temperatures, reducing flow when the radiator water is cold relative to the stack coolant (Krad) and while the coolant temperature is falling (KdTfc) to suppress the temperature drop caused by cold radiator coolant entering as the valve opens. Separately, it increases flow as the coolant temperature rises above the control target temperature (Tg), and reduces it below the target temperature. The instant application teaches that changing the flow in this manner produces a change in the claimed “hysteresis characteristic” and so such a change would be expected in Masui, including the claimed “difference between a temperature at which the thermostat valve on the radiator side starts to be” opened or closed.
Regarding Claim 20, Masui teaches or renders obvious:
continuous monitoring of the temperature, including comparing a difference to a predetermined value over and over, and so reading on “a second predetermined value equal to” the first predetermined value
Claims 5, 9, 11, 13, 15, 17, and 21 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Masui (JP 2014-120386 to Masui). Alternatively, they are rejected as obvious under 35 U.S.C. 103 as being unpatentable over Masui in view of Borasso (EP 3444461 to Borrasso et al.) and Cunningham (US 2019/0234291 to Cunningham et al.).
Regarding Claims 5 and 9, Masui teaches:
a cooling system for a fuel cell 10 with a refrigerant flow channel, a radiator 50 configured to radiate heat from the refrigerant that has passed through the fuel cell, a bypass flow channel LB configured to bypass the radiator, and a thermostat valve 40 configured to select a flow path for the refrigerant between the radiator and the bypass flow channel according to a temperature of the refrigerant (Fig. 1, ¶ 0020-0021)
a temperature sensor 30 configured to measure a temperature of the refrigerant that has passed through the fuel cell as part of the refrigerant loop (Fig. 1, ¶ 0022)
a controller configured to control the temperature of the fuel cell stack, which requires determining a target temperature and comparing it to the sensed outlet temperature (¶ 0048, 0057-0059)
an embodiment in which the controller determines a target stack outlet coolant temperature and compares it to a target temperature (¶ 0061), determines that the fuel cell temperature should be raised or lowered to meet the target temperature (¶ 0066-0067, 0071), and setting the flow rate of the coolant higher or lower to supply or remove the required quantity of heat (¶ 0071-0073)
The limitations referring “temporarily fully closed or fully opened to reset an influence of a temperature hysteresis characteristic” are interpreted to be obvious in view of the fact that the valve in Masui will have what are, practically speaking “fully open” and “fully closed” positions, determined by the end points of the wax melting range. Being opened or closed is temporary in the sense that control up and down will change the opening of the valve.
Masui talks about a specific example, such as warm-up, but also either directly teaches or implies that target temperatures can be higher or lower, and the coolant flow rate can be increased, or decreased, to supply or remove heat from the fuel cell. Masui also changes the flow rate of the coolant, including increasing the flow rate above the basic target flow in order to reduce hunting. This change in the flow rate inherently “changes the temperature hysteresis characteristic” of the valve, within the broadest reasonable interpretation of the claims, because it has all the essential elements of such a change as described by the instant specification. That is, Masui has a circulation pump in series and downstream of the thermostat valve, so the changing the flow rate at the pump changes the flow rate through the valve, substantially similar to the instant invention. Masui adjusts the flow based on the fuel cell coolant temperatures, reducing flow when the radiator water is cold relative to the stack coolant (Krad) and while the coolant temperature is falling (KdTfc) to suppress the temperature drop caused by cold radiator coolant entering as the valve opens. Separately, it increases flow as the coolant temperature rises above the control target temperature (Tg), and reduces it below the target temperature. The instant application teaches that changing the flow in this manner produces a change in the claimed “hysteresis characteristic” and so such a change would be expected in Masui.
Additionally, Borasso is cited for teaching a deliberate correction of wax-thermostat hysteresis in cooling and heating of an engine, including a radiator, valve, and pump in a coolant system that mirrors that taught in Masui and in the instant application (abstract, ¶ 0023-0039). Borasso teaches an electrical heating element 7 that heats the wax valve, changing its hysteresis characteristic, in response to a controller’s determination to change the fuel cell temperature via manipulating the coolant. It teaches, in other words, that hysteresis and reversal delay in a wax thermostat were recognized control errors that could be fixed by a controller applying direction-dependent correction to the wax thermostat. Masui teaches this through radiator change (i.e. fan control) and through coolant flow rate. It would have been obvious based on the prior art of record to change the hysteresis characteristic of the valve in order to improve heating and cooling of the fuel cell of Masui, depending on whether the fuel cell target temperature was higher or lower than the sensed outlet temperature.
Masui (in view of Borasso) therefore teaches and/or renders obvious reducing the radiation capacity of the radiator or a flow rate of the coolant to cause the fuel cell temperature to increase towards a target and increasing the radiation capacity of the radiator or a flow rate of the coolant to cause the fuel cell temperature to decrease towards a target.
Masui does not explicitly teach the specific claimed ordering:
causing the thermostat valve on the radiator side to be fully closed by temporarily decreasing the temperature of the refrigerant flowing through the thermostat valve and then reducing the radiation capacity of the radiator or a flow rate of the refrigerant to allow the fuel cell temperature to increase towards target
the opposite, or causing the thermostat valve on the radiator to be fully opened by temporarily increasing the temperature of the refrigerant flowing through the thermostat valve and then increasing the radiation capacity of the radiator or the flow rate of the refrigerant to allow the fuel cell temperature to decrease towards target
Borasso however, teaches causing the thermostat valve to be fully opened by heating it and its vicinity, including the coolant flowing through it, in order to fully open the radiator side of the valve, to reduce the temperature of the engine (¶0044-0046). It also teaches causing the thermostat valve to be fully closed by cooling it via a cooling means (¶ 0047-0060). This allows the thermostat valve to be controlled independently of the coolant’s temperature in comparison to a naïve loop without the heating and cooling means. Furthermore, the heating and cooling of the valve will also, by thermal conduction of those elements through the valve, “decrease the temperature of the refrigerant flowing through the thermostat valve” within the broadest reasonable of the claims, since the temperature of the coolant will be cooled/heated within the valve depending on the action of the heating/cooling elements, and thereby changing the hysteresis characteristic of the valve within the meaning of the claim.
Cunningham, meanwhile, related to a similar cooling loops for an engine, teaches waiting for the thermostat valve to fully open before beginning the operation of the radiator in order to save energy and more efficiently cool the engine (Fig. 3, ¶ 0008, 28, 0035, 0061). It would have been obvious to provide a heating/cooling means in the valve of a coolant/engine/radiator loop like that shown in Masui to more efficiently control the opening/closing of the valve, as taught in Borasso, and further, to only change the flow rate and/or radiative capacity of the radiator after the valve was fully open or closed in order to make the system more energy efficient.
Regarding Claims 11 and 13, Masui teaches:
changing the radiator capacity settings and changing the flow rate to effect the temperature changes as needed (¶ 0064)
Regarding Claims 15 and 17, Masui does not teach:
a flow rate regulation valve
Regarding Claim 21, Masui teaches or renders obvious:
continuous monitoring of the temperature, including comparing a difference to a predetermined value over and over, and so reading on “a second predetermined value equal to” the first predetermined value
Response to Arguments
Applicant's arguments filed 2026-08-18 have been fully considered but they are not persuasive. Applicant argues that Masui does not compare a target temperature to a detected temperature to determine whether a fuel cell needs to be hotter or colder before acting (Remarks at 14). This is not accurate. In response to the claim amendments new art is cited. Masui teaches substantially the same control scheme as the instant invention, varying the flow rate and/or the radiator capacity in response to meeting a target temperature.
Masui has a circulation pump in series and downstream of the thermostat valve, so the changing the flow rate at the pump changes the flow rate through the valve, substantially similar to the instant invention. Masui adjusts the flow based on the fuel cell coolant temperatures, reducing flow when the radiator water is cold relative to the stack coolant (Krad) and while the coolant temperature is falling (KdTfc) to suppress the temperature drop caused by cold radiator coolant entering as the valve opens. Separately, it increases flow as the coolant temperature rises above the control target temperature (Tg), and reduces it below the target temperature. The instant application teaches that changing the flow in this manner produces a change in the claimed “hysteresis characteristic” and so such a change would be expected in Masui, absent Applicant pointing out a specific difference in the operations. Applicant argues that Masui teaches dampening of the temperature “hunting” rather than changing a hysteresis characteristic, but fails to account for Masui’s explicit description of temperature control, and further fails to explain why such dampening does not “change a hysteresis characteristic” within the meaning of the claim.
In response to the amendments, new art is cited that teaches and renders obvious changing the hysteresis characteristics of a wax valve in a coolant loop substantially liked that used in Masui and other previously cited art. Such direct manipulation of the temperature of the wax valve would also affect the temperature of the coolant flowing through it, in a way to change the hysteresis characteristics of the valve. The instant invention does not teach such direct manipulation of the valve through heating/cooling elements in and around the valve, but the claims as written do not include limitations that would distinguish them over what is rendered obvious by the prior art—such as the particular method of manipulating the coolant temperature flowing through the valve to fully open or close it.
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Michael Dignan, whose telephone number is (571) 272-6425. The examiner can normally be reached from Monday to Friday between 10 AM and 6:30 PM. If any attempt to reach the examiner by telephone is unsuccessful, the examiner’s supervisor, Tiffany Legette, can be reached at (571)270-7078. Another resource that is available to applicants is the Patent Application Information Retrieval (PAIR). Information regarding the status of an application can be obtained from the (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAX. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, please feel free to contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). Applicants are invited to contact the Office to schedule an in-person interview to discuss and resolve the issues set forth in this Office Action. Although an interview is not required, the Office believes that an interview can be of use to resolve any issues related to a patent application in an efficient and prompt manner.
/MICHAEL L DIGNAN/Examiner, Art Unit 1723
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