Fuel cell system, fuel control apparatus thereof and fuel control method

Abstract

According to one embodiment of the present invention, a fuel cell system comprising a stack that generates electrical energy by electrochemically reacting air and hydrogen, a reformer that supplies reforming gas to the stack, a burner that supplies heat to the reformer, a first blower that supplies fuel gas to the burner, a second blower that supplies reforming raw material gas to the reformer, and a fuel control device that measures the temperature of the lower part of the reformer at predetermined time intervals and calculates the rate of change of temperature to generate a control signal for controlling the flow rates of the first blower and the second blower, respectively, is disclosed, along with a fuel control device and a fuel control method.

Description

Technology Field

[0001] The present invention relates to a fuel cell system, a fuel control device thereof, and a fuel control method. Background Technology

[0002] Fuel cell systems are devices that produce electrical energy using the electrochemical reaction between hydrogen and oxygen, and are utilized in various industrial fields as eco-friendly, high-efficiency energy sources.

[0003] The reformer in a fuel cell system is a component that produces hydrogen by reforming fuel, and the system's performance and efficiency depend on the reformer's operating temperature. Accordingly, the technology to precisely control the reformer's temperature within a certain range is essential for the stable operation of the fuel cell system.

[0004] Common temperature control methods widely used include simple ON / OFF control or the application of symmetric hysteresis bands. However, because reformers have high thermal inertia, they exhibit a delayed temperature response to external inputs; consequently, conventional simple control methods have limitations in stably maintaining the target temperature.

[0005] In particular, during the temperature rise phase, overshoot exceeding the target temperature is likely to occur due to control response delay, and during the temperature fall phase, undershoot falling excessively below the target temperature may occur. Furthermore, such repetitive transient responses cause significant fluctuations in fuel supply, leading to increased unnecessary fuel consumption and delaying the temperature stabilization time, which results in a decrease in the thermal efficiency of the entire system.

[0006] Therefore, there is a need for more precise and stable temperature control technology that takes into account the characteristics of reformers with high thermal inertia. The problem to be solved

[0007] The problem to be solved according to one embodiment of the present invention includes controlling the temperature of a reformer by controlling the fuel supply by reflecting the thermal response characteristics that appear differently in the temperature rise and fall sections.

[0008] The technical problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art to which the present invention belongs from the description below. means of solving the problem

[0009] To solve the above problem, a fuel cell system according to one aspect of the present invention may include a stack that generates electrical energy by electrochemically reacting air and hydrogen, a reformer that supplies reforming gas to the stack, a burner that supplies heat to the reformer, a first blower that supplies fuel gas to the burner, a second blower that supplies reforming raw material gas to the reformer, and a fuel control device that measures the temperature of the lower part of the reformer at predetermined time intervals and calculates the rate of change of temperature to generate a control signal for controlling the flow rates of the first blower and the second blower, respectively.

[0010] Here, a third blower that supplies air to the burner is further included, and the fuel control device can generate a control signal for controlling the third blower based on the rate of change of temperature.

[0011] Here, the fuel control device may include a temperature measuring unit that measures the temperature of the reformer at predetermined time intervals, a temperature change rate calculating unit that calculates the temperature change rate according to the time intervals based on the measured temperature value, and a control signal generating unit that generates a control signal for controlling the flow rate of at least one of the first blower, the second blower, and the third blower based on the calculated temperature change rate.

[0012] Here, the control signal generating unit can generate a first control signal to cut off fuel when the temperature change rate exceeds a preset condition.

[0013] Here, the control signal generating unit can generate a second control signal for supplying fuel when the temperature change rate is less than a preset condition.

[0014] A fuel control device of a fuel cell system according to another aspect of the present invention may include a temperature measuring unit that measures the temperature of a reformer at predetermined time intervals, a temperature change rate calculating unit that calculates a temperature change rate according to the time intervals based on the measured temperature value, and a control signal generating unit that generates a control signal for controlling the flow rate of at least one of a first blower, a second blower, and a third blower based on the calculated temperature change rate.

[0015] Here, the control signal generating unit can generate a first control signal to cut off fuel when the temperature change rate exceeds a preset condition.

[0016] Here, the control signal generating unit can generate a second control signal for supplying fuel when the temperature change rate is less than a preset condition.

[0017] A fuel control method performed in a fuel control device of a fuel cell system according to another aspect of the present invention may include the steps of: a temperature measuring unit measuring the temperature of a reformer at a predetermined time interval; a temperature change rate calculating unit calculating a temperature change rate according to the time interval based on the measured temperature value; and a control signal generating unit generating a control signal for controlling the flow rate of at least one of a first blower, a second blower, and a third blower based on the calculated temperature change rate.

[0018] Here, the step of generating the control signal may generate a first control signal for cutting off fuel when the rate of change in temperature exceeds a preset condition.

[0019] Here, the step of generating the control signal may generate a second control signal for supplying fuel when the temperature change rate is less than a preset condition. Effects of the invention

[0020] As described above, according to the embodiments and various aspects of the present invention, by applying different control criteria to the rising and falling sections using an asymmetric control method, the thermal fluctuation range of the reformer can be minimized to improve thermal stability and increase the reliability and operational efficiency of the system.

[0021] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the composition of the invention described in the description or claims of the present invention. Brief explanation of the drawing

[0022] FIG. 1 is a drawing showing a fuel cell system according to one embodiment of the present invention. FIG. 2 is a block diagram showing a fuel control device of a fuel cell system according to one embodiment of the present invention. FIGS. 3 and 4 are flowcharts illustrating a fuel control method of a fuel cell system according to an embodiment of the present invention. Specific details for implementing the invention

[0023] The present invention will be described below with reference to the attached drawings. However, the present invention may be implemented in various different forms and is therefore not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification have been given similar reference numerals.

[0024] Throughout the specification, when it is stated that a part is "connected (connected, in contact, combined)" with another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly connected" with other members interposed between them. Furthermore, when it is stated that a part "includes" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but rather allows for the inclusion of additional components.

[0025] The terms used herein are merely for describing specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprising” or “having” are intended to indicate the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0026] Embodiments of the present invention will be described in detail below with reference to the attached drawings.

[0027] One embodiment of the present invention relates to a fuel cell system, a fuel control device thereof, and a fuel control method.

[0028] FIG. 1 is a drawing showing a fuel cell system according to one embodiment of the present invention.

[0029] Referring to FIG. 1, a fuel cell system (10) according to one embodiment of the present invention may include a stack (100), a reformer (200), a burner (300), a first blower (410), a second blower (420), a third blower (500), and a fuel control device (600).

[0030] A fuel cell system (10) according to one embodiment of the present invention is a reforming type fuel cell system that generates hydrogen using natural gas (NG) and air and supplies it to a stack (100) to produce electricity.

[0031] The stack (100) generates electrical energy by electrochemically reacting hydrogen (H2) supplied from the reformer (200) with air, and after the reaction, the unreacted gas can be discharged in the form of anode off gas (AOG).

[0032] The reformer (200) can convert the supplied reforming feedstock gas into a hydrogen-containing reforming gas through a steam reforming (SR) reaction, a water gas shift (WGS) reaction, and a selective oxidation (Prox) reaction, and supply it to the stack (100).

[0033] The burner (300) can provide the heat required for the reformer (200) by burning the fuel gas supplied through the first blower (410) and the air supplied through the third blower (500). The second blower (420) can supply the reforming raw material gas to the reformer (200).

[0034] The fuel control device (600) can measure the temperature of the lower part of the reformer at predetermined time intervals and calculate the rate of change of temperature to generate a control signal for controlling the flow rates of the first blower (410) and the second blower (420), respectively. Additionally, based on the rate of change of temperature, it can generate a control signal for controlling the third blower (500).

[0035] Specifically, the fuel control device (600) can measure the temperature at predetermined time intervals through a temperature sensor installed at the bottom of the reformer (200) and calculate the temperature change rate ΔT(t) from the amount of temperature change over time.

[0036] At this time, the case where ΔT(t) > 0 can be determined as a temperature rise section, and the case where ΔT(t) < 0 can be determined as a temperature fall section. The fuel control device (600) uses the calculated temperature change rate and the reference temperature T ref A control signal for controlling the flow rate of the first blower (410) and the second blower (420) can be generated using this, and a signal for controlling the air supply amount of the third blower (500) can also be generated as needed.

[0037] In the temperature rise section (ΔT(t) > 0), since the temperature may continue to rise for a certain period of time even after the fuel is cut off due to the thermal inertia of the reformer (200), the fuel control device (600) measures the temperature at the reference temperature T ref It can be controlled to cut off the fuel supply before reaching it.

[0038] For example, in the temperature rise section, the fuel control device (600) measures the temperature as a reference temperature T ref The first set temperature (T) before reaching ref -ΔT up When it reaches ), the rotational speed of the first blower (410) can be reduced or stopped to block or minimize the flow rate of fuel gas supplied to the burner (300).

[0039] Accordingly, the combustion heat of the burner (300) is reduced, and the temperature of the reformer (200) can be induced to naturally rise to a target range by the residual heat. At this time, the second blower (420) can be maintained at a flow rate corresponding to the basic flow rate or load conditions set to maintain the reaction stability of the reformer (200), and a slight reduction control can be performed if necessary to prevent additional heat generation due to excessive reforming reaction.

[0040] In addition, the third blower (500) can be controlled to reduce the air flow rate in proportion to the reduction in the fuel flow rate of the first blower (410) so that the excess air rate of the burner (300) does not change abruptly.

[0041] Accordingly, the temperature naturally rises to the target range due to residual heat, which can reduce overshoot and prevent excessive fuel supply, thereby reducing fuel consumption.

[0042] Conversely, in the temperature drop section (ΔT(t) < 0), to prevent the temperature from rapidly dropping below the reference temperature, the minimum fuel value F is used before reaching the reference temperature. min It can be controlled to supply it preemptively.

[0043] For example, in the temperature drop section, the fuel control device (600) measures the temperature at the reference temperature T ref The second set temperature (T) before reaching ref +ΔT down At the point where it decreases below ), the rotational speed of the first blower (410) is increased to the minimum fuel value F min The above can be controlled to be supplied to the burner (300).

[0044] Accordingly, the amount of combustion heat in the burner (300) is increased preemptively, thereby mitigating the temperature drop of the reformer (200) and suppressing undershoot. At this time, the third blower (500) can be controlled to increase the air flow rate in response to the increased fuel flow rate to maintain an appropriate air-fuel ratio.

[0045] Meanwhile, the second blower (420) maintains a basic set flow rate to maintain the reaction conditions of the reformer (200), but can be controlled to increase or decrease in stages as needed, taking into account the temperature recovery rate.

[0046] Such pre-fuel correction can suppress undershoot and shorten the time to return to the target temperature range, and has the effect of reducing the amount of fuel required for reheating.

[0047] According to one embodiment of the present invention, the control signal applied to each blower may be a drive control signal for flow rate control. For example, the control signal generating unit (650) may generate a speed control signal (RPM control signal) or an inverter drive signal (PWM signal) for controlling the rotational speed of the first blower (410), the second blower (420), and the third blower (500). Accordingly, the motor drive voltage or frequency of each blower may be adjusted to change the supply flow rate.

[0048] If fuel cutoff is required during the temperature rise section, a control signal corresponding to a stop or minimum rotational speed may be applied to the first blower (410), and in conjunction with this, a deceleration or stop signal may also be applied to the third blower (500). Conversely, if minimum fuel supply is required during the temperature fall section, a minimum fuel value F is applied to the first blower (410). min A rotational speed control signal corresponding to this may be applied, and a control signal for securing an air flow rate corresponding to this may be applied to the third blower (500). The second blower (420) may be set to have a rotational speed control signal applied to maintain the basic supply conditions of the reforming raw material gas, or may be adjusted stepwise according to the operating conditions.

[0049] Meanwhile, according to one embodiment of the present invention, asymmetric hysteresis control can be performed by applying different hysteresis widths to the temperature rise section and the temperature fall section.

[0050] For example, in the temperature rise section, the hysteresis width is set relatively narrow to enable early shutdown, and in the temperature fall section, the hysteresis width is set relatively wide to secure a minimum fuel supply section, thereby enabling fuel supply control suitable for the thermal inertia characteristics of the reformer (200).

[0051] Here, setting the hysteresis width relatively narrow means reducing the temperature deviation range at which fuel supply cutoff or control switching occurs during the temperature rise section, so that control action is performed before reaching the reference temperature.

[0052] This asymmetric control method can contribute to reducing temperature fluctuations, lowering fuel and power consumption, and improving the thermal stability of the reformer.

[0053] FIG. 2 is a block diagram showing a fuel control device of a fuel cell system according to one embodiment of the present invention.

[0054] Referring to FIG. 2, a fuel control device (600) of a fuel cell system according to one embodiment of the present invention may include a reference temperature setting unit (610), a minimum fuel value input unit (620), a temperature measurement unit (630), a temperature change rate calculation unit (640), and a control signal generation unit (650).

[0055] The reference temperature setting unit (610) is a reference temperature T which is the target operating temperature of the reformer (200). ref And, offset values ​​(e.g., α, β) for controlling the rising and falling intervals can be set or stored. These values ​​can be stored in memory and used in control operations.

[0056] The minimum fuel value input section (620) is the minimum fuel value F to be supplied in the temperature drop section. min It can be set or received. The above minimum fuel value can be used as a lower limit fuel flow rate standard to prevent undershoot.

[0057] The temperature measuring unit (630) can measure a temperature value T(t) at a predetermined time interval Δt from a temperature sensor placed at the bottom of the reformer (200).

[0058] The temperature change rate calculation unit (640) can calculate the temperature change rate according to the time interval based on the measured temperature value.

[0059] Specifically, the temperature change rate calculation unit (640) can calculate the temperature change rate using the following mathematical formula 1 using the current temperature T(t) and the previous temperature T(t-Δt).

[0060]

[0061] Here, if the calculated ΔT(t) is greater than 0, it can be determined as a temperature rising section, and if it is less than 0, it can be determined as a temperature falling section.

[0062] The control signal generation unit (650) can generate a control signal for controlling the flow rate of at least one of the first blower, the second blower, and the third blower based on the calculated temperature change rate.

[0063] Specifically, the control signal generating unit (650) calculates the temperature change rate ΔT(t) and the reference temperature T ref A control signal can be generated based on.

[0064] If the control signal generation unit (650) exceeds a preset condition for the rate of change of temperature, it can generate a first control signal to cut off the fuel.

[0065] That is, in the temperature rise region (ΔT(t) > 0), T(t)≥T ref In the case of -α, a first control signal for fuel cutoff can be generated to control the first blower (410) so that the fuel flow rate supplied to the burner (300) becomes F(t)=0.

[0066] Meanwhile, the control signal generation unit (650) can generate a second control signal for supplying fuel when the temperature change rate is less than a preset condition.

[0067] That is, in the temperature decrease region (ΔT(t) < 0), T(t) ≤ T ref In the case of +β, a second control signal for minimum fuel supply is generated so that the fuel flow rate is F(t)=F min The first blower (410) can be controlled to become like this.

[0068] Additionally, the control signal generation unit (650) can generate a signal to control the air flow rate of the third blower (500) in conjunction with changes in the fuel flow rate, and can generate a signal to maintain or adjust the flow rate of the second blower (420) within the range required to maintain the reforming conditions.

[0069] The fuel control unit (600) can be implemented as a controller including a processor and memory.

[0070] The processor may include a microprocessor (MPU), a microcontroller unit (MCU), a digital signal processor (DSP), or an equivalent computing device, and can perform processing of temperature measurement data, calculation of the rate of temperature change, comparison with a reference temperature, and generation of control signals by executing program instructions stored in memory.

[0071] The memory may include non-volatile memory and / or volatile memory. The non-volatile memory includes a control program, a reference temperature T ref , offset values ​​α, β, minimum fuel value F min Setting values ​​such as the sampling period Δt can be stored, and data generated during the calculation process, such as the real-time measured temperature value T(t), the previous temperature value T(t-Δt), and the calculated temperature change rate ΔT(t), can be temporarily stored in the volatile memory.

[0072] The processor can periodically collect data input from the temperature measuring unit (630) by executing instructions stored in memory, perform calculations of the temperature change rate calculation unit (640), and output a control signal to control the first blower (410), the second blower (420), and the third blower (500) through the control signal generating unit (650) according to the result.

[0073] FIGS. 3 and 4 are flowcharts illustrating a fuel control method of a fuel cell system according to an embodiment of the present invention.

[0074] Referring to FIGS. 3 and 4, a fuel control method for a fuel cell system according to one embodiment of the present invention is performed in a fuel control device of a fuel cell system, and in step S100, a temperature measuring unit measures the temperature of a reformer at predetermined time intervals.

[0075] Subsequently, in step S200, the temperature change rate calculation unit calculates the temperature change rate according to the time interval based on the measured temperature value. The calculated temperature change rate is used as an indicator to determine the thermal state of the reformer (200).

[0076] In step S300, the control signal generator generates a control signal for controlling the flow rate of at least one of the first blower, the second blower, and the third blower based on the calculated temperature change rate.

[0077] Specifically, in step S300, the control signal generation unit (650) calculates the ΔT(t) and the reference temperature T stored in the reference temperature setting unit (610). ref , minimum fuel value F stored in the minimum fuel value input section (620) min A control signal is generated to control the flow rate of at least one of the first blower (410), the second blower (420), and the third blower (500) by referring to the above.

[0078] Here, the step of generating a control signal (S300) generates a first control signal for cutting off fuel when the rate of change in temperature in steps S310 to S320 exceeds a preset condition. Accordingly, in step S410, at least one of the first blower, the second blower, and the third blower can be controlled to cut off fuel.

[0079] Specifically, when it is determined that the temperature rises, a first control signal is generated in step S320, and the first blower (410) can be controlled to cut off the fuel supplied to the burner (300) in step S410. At this time, the fuel flow rate is controlled to F(t)=0, and in conjunction with this, the air flow rate of the third blower (500) can also be reduced or stopped. If necessary, the flow rate of the second blower (420) can also be maintained or adjusted to suit the operating conditions.

[0080] Meanwhile, the step of generating a control signal (S300) generates a second control signal for supplying fuel when the rate of change of temperature in steps S330 to S340 is less than a preset condition. Accordingly, in step S420, at least one of the first blower, the second blower, and the third blower can be controlled to supply fuel.

[0081] Specifically, if it is determined to be a temperature decrease section, a second control signal is generated in step S340, and a minimum fuel value F is generated in step S420. min The first blower (410) is controlled to supply this. Accordingly, combustion of the burner (300) is maintained, and the third blower (500) can be controlled to supply an air flow rate corresponding to the fuel flow rate. The second blower (420) can maintain a basic flow rate to maintain the reaction conditions of the reformer (200) or be adjusted in steps.

[0082] Additionally, the step of generating a control signal (S300) can determine a stable section if the temperature change rate in step S350 is a preset condition.

[0083] That is, if ΔT(t)=0 or is within a preset tolerance range, it can be determined as a stable section in step S350, and in this case, control can be maintained to maintain the existing operating conditions.

[0084] As such, the fuel control method of FIGS. 3 and 4 can implement asymmetric control suitable for the thermal inertia characteristics of the reformer (200) by distinguishing the rising section, the falling section, and the stable section according to the rate of change of temperature, and by performing fuel and air flow rate control corresponding to each section.

[0085] Combinations of each block of the block diagram attached to this specification and each step of the flowchart may be performed by computer program instructions. Since these computer program instructions may be loaded into the processor of a general-purpose computer, a computer for special purposes, or other programmable data processing equipment, the instructions executed through the processor of the computer or other programmable data processing equipment create means for performing the functions described in each block of the block diagram or each step of the flowchart. Since these computer program instructions may also be stored in computer-available or computer-readable memory that can be directed toward the computer or other programmable data processing equipment to implement the function in a specific manner, the instructions stored in computer-available or computer-readable memory may also produce a manufactured item containing instruction means for performing the function described in each block of the block diagram or each step of the flowchart. Since computer program instructions can be loaded onto a computer or other programmable data processing equipment, instructions that execute a computer or other programmable data processing equipment by performing a series of operation steps on the computer or other programmable data processing equipment to create a process executed by the computer can also provide steps for executing the functions described in each block of the block diagram and each step of the flowchart.

[0086] Additionally, each block or each step may represent a module, segment, or part of code containing one or more executable instructions for executing a specified logical function(s). Also, it should be noted that in some alternative embodiments, the functions mentioned in the blocks or steps may occur out of order. For example, two blocks or steps described in succession may actually be performed substantially simultaneously, or the blocks or steps may sometimes be performed in reverse order according to the corresponding function.

[0087] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0088] The scope of the present invention is defined by the claims set forth below, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention.

Claims

Claim 1 A stack that generates electrical energy by electrochemically reacting air and hydrogen; a reformer that supplies reforming gas to the stack; a burner that supplies heat to the reformer; a first blower that supplies fuel gas to the burner; a second blower that supplies reforming raw material gas to the reformer; and a fuel control device that measures the temperature of the lower part of the reformer at predetermined time intervals, calculates the rate of change of temperature, and generates a control signal for controlling the flow rates of the first blower and the second blower, respectively, wherein the fuel control device comprises: a temperature measuring unit that measures the temperature of the reformer at predetermined time intervals; and a temperature change rate calculating unit that calculates the rate of change of temperature according to the time intervals based on the measured temperature value. A fuel cell system comprising a control signal generating unit that generates a control signal for controlling the flow rates of the first blower and the second blower, respectively, based on the calculated temperature change rate, wherein the control signal generating unit generates a first control signal for cutting off fuel supplied to the burner when the measured temperature reaches a first set temperature lower than a reference temperature in a temperature rise section where the temperature change rate is positive, and generates a second control signal for supplying fuel greater than or equal to a preset minimum fuel value (Fmin) to the burner when the measured temperature decreases to a second set temperature higher than the reference temperature in a temperature fall section where the temperature change rate is negative, and wherein the first set temperature and the second set temperature are set as different control standards for the temperature rise section and the temperature fall section. Claim 2 A fuel cell system according to claim 1, further comprising a third blower that supplies air to the burner, wherein the fuel control device generates a control signal for controlling the third blower based on the rate of change of temperature. Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 delete Claim 7 delete Claim 8 delete Claim 9 A fuel control method performed by a fuel control device of a fuel cell system comprising: a stack that generates electrical energy by electrochemically reacting air and hydrogen; a reformer that supplies reforming gas to the stack; a burner that supplies heat to the reformer; a first blower that supplies fuel gas to the burner; a second blower that supplies reforming raw material gas to the reformer; and a fuel control device that measures the temperature of the lower part of the reformer at predetermined time intervals, calculates a rate of temperature change, and generates a control signal for controlling the flow rates of the first blower and the second blower, respectively, the method comprising: a step in which a temperature measuring unit measures the temperature of the reformer at predetermined time intervals; and a step in which a temperature change rate calculating unit calculates a rate of temperature change according to the time intervals based on the measured temperature value. A fuel control method comprising: a step of generating a control signal to control the flow rates of a first blower and a second blower, respectively, based on the calculated temperature change rate of the control signal generating unit; wherein the step of generating the control signal comprises: a step of generating a first control signal to cut off fuel supplied to the burner when the measured temperature reaches a first set temperature lower than a reference temperature in a temperature rise section where the temperature change rate is positive; and a step of generating a second control signal to supply fuel greater than or equal to a preset minimum fuel value (Fmin) to the burner when the measured temperature decreases to a second set temperature higher than the reference temperature in a temperature fall section where the temperature change rate is negative; wherein the first set temperature and the second set temperature are set as different control standards for the temperature rise section and the temperature fall section. Claim 10 delete Claim 11 delete

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