JP2003112902A - Apparatus for controlling fuel reformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel reformer controlling apparatus for managing the peak temperature of a reformation reactor by using a small number of thermometers, controlling the supply amount of fuel according to the degree of deterioration of the reformation reactor and announcing the fact that the reformation reactor is deteriorated to such a degree that the performance of the reformation reactor can not be kept when the fact is detected. SOLUTION: A temperature sensor 9 measures the temperature of the reformation reactor 1. A temperature estimating part 45 estimates the estimate of the peak temperature being the highest temperature of the reactor 1 according to operation conditions and the temperature measured by the sensor 9. A deterioration estimating part 46 estimates the estimate of deterioration showing the degree of deterioration of the reactor 1 according to a deviation between the estimate of the peak temperature and the temperature measured by the sensor 9. An information presenting unit 32 announces abnormality when the estimate of deterioration exceeds a prescribed value. A targeted value producing part 42 restricts the supply amount of the fuel to be generated according to the estimate of deterioration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a fuel reformer that produces hydrogen-rich fuel gas from raw fuel, and more particularly, to a fuel reformer that can perform appropriate control even when the reformer deteriorates. Control device.

[0002]

2. Description of the Related Art As a method for producing a fuel gas for a fuel cell,
A method is known in which a hydrogen-rich fuel gas is obtained by reforming a fuel from a hydrocarbon-based raw fuel such as alcohol or gasoline. For example, in Japanese Patent Laid-Open No. 10-169908,
A fuel cell that reforms and uses methanol is disclosed. According to this conventional technique, methanol vapor obtained by evaporating methanol as a raw fuel, steam generated by a steam generator, and air compressed by an air compressor are introduced into a reforming reactor to perform a reforming reaction. To produce hydrogen-rich fuel gas. This reforming reaction includes a partial oxidation reaction that produces hydrogen and carbon dioxide from methanol and oxygen in the air, and a steam reforming reaction that produces hydrogen and carbon dioxide from methanol and water.

[0003]

However, in the above-mentioned conventional reforming, the partial oxidation reaction is an exothermic reaction,
Since the steam reforming reaction is an endothermic reaction, the temperature inside the reforming reactor is not constant, and there is a problem in that the deterioration of the reforming catalyst progresses due to a partial temperature rise, leading to deterioration of the reformer performance. there were. Once the catalyst in the reactor has deteriorated, the catalyst in the deteriorated part will never be activated again. Further, if the reforming reaction is carried out with the catalyst having a deteriorated portion, there is a problem that abnormal deterioration of the reactor itself and deterioration of fuel consumption are caused.

Therefore, in order to improve reliability and fuel efficiency,
It is necessary to control so that the temperature does not become high enough to cause deterioration, estimate the deterioration, and perform appropriate control.
For this, it is possible to measure the temperature in the reformer and control so as not to exceed the target value.

However, the temperature distribution of the reforming reactor changes depending on operating conditions and deterioration with time, and the peak temperature position also changes. If the temperature of the reforming reactor is controlled by the measured value measured by one thermometer, the operating conditions such that the mounting position of the thermometer reaches the peak temperature are good, but if the operating conditions change or deterioration with time progresses. Even if the temperature is lower than the target temperature at the thermometer mounting position, the temperature may be higher at other locations.

A method of taking an image showing the temperature distribution of the reforming reactor with an infrared camera and controlling the temperature on the basis of this image signal is also conceivable, but the above-mentioned sensor for realizing these is very expensive. . A method of grasping the temperature distribution of the reforming reactor by using multiple temperature sensors instead of the distributed constant type sensor is also conceivable, but it requires several tens of temperature sensors and the control becomes complicated, resulting in cost increase. Inevitable.

In view of the above problems, an object of the present invention is to provide a control device for a reforming reactor which can manage the peak temperature at all times even with a small number of thermometers even when it is deteriorated.

Another object of the present invention is to appropriately control the fuel flowing into the reforming reactor even when the reforming reactor is deteriorated, and to detect the deterioration when the performance cannot be maintained. An object of the present invention is to provide a control device of a reforming reactor that can notify.

[0009]

The invention according to claim 1 is
In order to achieve the above object, in a control device of a fuel reformer that reforms a raw fuel to produce a fuel gas containing hydrogen, a temperature for measuring a temperature in a reforming reactor containing a reforming catalyst. Measuring means, temperature estimating means for estimating a peak temperature which is at least the highest temperature in the reforming reactor based on operating conditions of the fuel reformer, and temperature estimation estimated by the temperature estimating means. And a deterioration estimating means for estimating the degree of deterioration of the reforming reactor based on a deviation between the value and the temperature measured by the temperature measuring means.

In order to achieve the above object, the invention according to claim 2 is the control device for a fuel reformer according to claim 1, wherein the temperature estimating means is the temperature measuring means in the reforming reactor. Measuring position temperature estimating means for estimating the temperature at the mounting position, correction means for correcting the temperature estimated value based on a deviation between the measured position temperature estimated value estimated by the measured position temperature estimating means and the temperature measured value. And the deterioration estimating means estimates the degree of deterioration of the reforming reactor based on the deviation between the measured position temperature estimated value and the temperature measured value.

In order to achieve the above object, the invention according to claim 3 is the control device for a fuel reformer according to claim 2, wherein the temperature estimating means reforms in accordance with an operating condition and the degree of deterioration. A plurality of temperature characteristic maps storing temperature characteristics of the reactor, wherein the correction means changes the selection of the temperature characteristic map based on a deviation between the measured position temperature estimated value and the temperature measured value. Use as a summary.

In order to achieve the above object, the invention according to claim 4 is the control device for a fuel reformer according to any one of claims 1 to 3, wherein the deterioration estimating means comprises:
The point is that deterioration is not estimated in the initial state of startup.

According to a fifth aspect of the present invention, in order to achieve the above object, in the fuel reformer control device according to any one of the first to fourth aspects, the deterioration estimating means includes:
The main point is that the deterioration is not estimated during the operation transient state.

In order to achieve the above object, the invention according to claim 6 is the outside air temperature measurement for measuring the temperature of outside air in the control device for a fuel reformer according to any one of claims 1 to 5. The gist of the present invention is that the temperature estimation means corrects the temperature estimation value according to the outside air temperature.

According to a seventh aspect of the present invention, in order to achieve the above object, in the fuel reformer control device according to the second aspect, the deviation is within a range of a first predetermined value or more and a second predetermined position or less. In this case, the gist is that the deterioration estimating means determines that the temperature is aged, and the correcting means switches the temperature estimating method from the temperature estimating method in the normal state to the temperature estimating method in the aged deterioration.

In order to achieve the above object, the invention according to claim 8 is the control device for a fuel reformer according to claim 2, wherein when the deviation exceeds a second predetermined value, the deterioration estimating means is abnormally deteriorated. It is the gist to judge as.

In order to achieve the above object, the invention according to claim 9 is, in the control device for a fuel reformer according to claim 8, notifying means for notifying an abnormality of the fuel reformer when it is judged as abnormal deterioration. The summary is that

In order to achieve the above object, the invention according to claim 10 is the fuel reformer controller according to claim 2, wherein the fuel reformer uses the reformed fuel gas to generate electricity. Voltage detector for detecting the actual cell voltage, required voltage calculation means for calculating the required cell voltage according to the required power for the fuel cell, and the actual cell voltage and the demand when the deviation is equal to or less than a second predetermined value. If the difference from the cell voltage is equal to or larger than the third predetermined value, a notification means for notifying an abnormality of the fuel reformer is provided.

In order to achieve the above object, the invention according to claim 11 is the control device for a fuel reformer according to any one of claims 1 to 10, wherein the degree of deterioration due to the deterioration estimating means is determined. Accordingly, the gist is to control the amount of raw fuel supplied to the reforming reactor.

[0020]

According to the first aspect of the present invention, in a control device of a fuel reformer for reforming a raw fuel to produce a fuel gas containing hydrogen, a reforming reaction containing a reforming catalyst. Temperature measuring means for measuring a temperature in the reactor, temperature estimating means for estimating a peak temperature which is at least the highest temperature in the reforming reactor based on operating conditions of the fuel reformer, The deterioration estimation means for estimating the degree of deterioration of the reforming reactor based on the deviation between the temperature estimation value estimated by the temperature estimation means and the temperature measurement value by the temperature measurement means, It becomes possible to estimate the degree of deterioration of the reforming reactor by utilizing the fact that the deterioration of the reactor appears as a change in temperature, and it is possible to estimate the temperature distribution of the reforming reactor according to the operating conditions from the degree of deterioration. By using
It becomes possible to control the peak temperature, which is the highest temperature in the reforming reactor, to be below the control temperature, including the effect of deterioration. This has the effect of preventing deterioration.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, the temperature estimating means estimates the temperature at the mounting position of the temperature measuring means in the reforming reactor. The deterioration estimation is provided with a measurement position temperature estimation means, a measurement position temperature estimation value estimated by the measurement position temperature estimation means, and a correction means for correcting the temperature estimation value based on a deviation between the temperature measurement value. The means estimates a degree of deterioration of the reforming reactor based on a deviation between the measured position temperature estimated value and the temperature measured value, thereby further estimating the temperature estimated value and the temperature based on the more accurate temperature estimated value. The deviation from the measured value can be calculated, and the accuracy of the deterioration estimation can be increased.

According to the invention of claim 3, in addition to the effect of the invention of claim 2, the temperature estimating means stores the temperature characteristic of the reforming reactor according to the operating condition and the degree of deterioration. A plurality of temperature characteristic maps, the correction means,
Since the selection of the temperature characteristic map is changed based on the deviation between the measured position temperature estimated value and the temperature measured value, there is an effect that the temperature estimating means has a simple configuration.

According to the invention of claim 4, in addition to the effects of the invention of claims 1 to 3, the deterioration estimating means does not perform deterioration estimation in the initial state of activation. In addition, it is possible to judge deterioration except in the initial stage of starting when the temperature of the reforming reactor is unstable, and it is possible to improve the accuracy of deterioration estimation.

According to the invention of claim 5, in addition to the effects of the inventions of claims 1 to 4, the deterioration estimating means does not perform deterioration estimation during an operation transient state. In addition, there is no need for a complicated model or a high-density map necessary for accurately estimating deterioration in an operating transient state, and there is an effect that the structure of the deterioration estimating means can be simplified.

According to the invention of claim 6, in addition to the effects of the inventions of claims 1 to 5, there is provided an outside air temperature measuring means for measuring the temperature of the outside air, and the temperature estimating means comprises the outside air. Since the estimated temperature value is corrected by the temperature, there is an effect that the reforming reactor temperature that is easily affected by the outside air temperature can be estimated more accurately.

According to the invention of claim 7, in addition to the effect of the invention of claim 2, the deviation is not less than a first predetermined value,
In addition, when it is within the range of the second predetermined position or less, the deterioration estimating unit judges that the deterioration is due to aging, and the correcting unit switches the temperature estimation method from the temperature estimation method at the normal time to the temperature estimation method at the deterioration over time. Therefore, there is an effect that the temperature can be accurately estimated even after deterioration over time.

According to the invention described in claim 8, in addition to the effect of the invention described in claim 2, when the deviation exceeds the second predetermined value, the deterioration estimating means determines that the deterioration is abnormal. The effect is that early detection of abnormal deterioration is possible.

According to the invention described in claim 9, in addition to the effect of the invention described in claim 8, when it is judged as abnormal deterioration, a notifying means for notifying the abnormality of the fuel reformer is provided, so that the detection can be performed. This is effective in notifying the operator of the fuel reformer of the abnormal deterioration.

According to the invention of claim 10, claim 2
In addition to the effects of the invention described, a voltage detector that detects the actual cell voltage of a fuel cell that generates power using the fuel gas reformed by the fuel reformer, and a required cell voltage according to the required power for the fuel cell. If the difference is less than or equal to a second predetermined value and the difference between the actual cell voltage and the required cell voltage is greater than or equal to a third predetermined value, an abnormality of the fuel reformer is notified. Even if the abnormality of the fuel reformer based on the temperature cannot be detected, the required cell voltage and the actual cell voltage are different, and the reforming capacity of the fuel reformer is lowered. If there is a possibility, it is possible to detect an abnormality in the fuel reformer.

According to the invention of claim 11, claim 1
In addition to the effects of the invention according to claim 10, since the amount of raw fuel supplied to the reforming reactor is controlled according to the degree of deterioration by the deterioration estimating means, there is deterioration over time. Since the load capacity of the reforming reactor can be maximized and it is possible to prevent the raw fuel from flowing in more than necessary, it is possible to prevent deterioration of fuel efficiency due to deterioration. .

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a fuel cell system to which a control device for a fuel reformer according to the present invention is applied, in which methanol and water are used as raw fuels and hydrogen is generated by the fuel reformer. 1 shows an electric vehicle powered by a fuel cell that operates.

In FIG. 1, the fuel reformer is an evaporator 3
A reforming reactor 1 containing a reforming catalyst and a carbon monoxide (CO) remover 8, and the control device of the fuel reformer is
The ECU 40.

First, the fuel reformer, the fuel cell main body 12 and its peripheral components will be described according to the gas path, and then the control device and other components realized by the ECU 40 will be described.

The flow rates of methanol supplied from the fuel tank 23 and water supplied from the water tank 21 are controlled by the fuel control device 22 and the water flow rate control device 20, respectively, and are supplied to the evaporator 3. The evaporator 3 uses the heat quantity of the exhaust gas from the combustor 17 described later to heat and evaporate the supplied methanol and water to generate methanol vapor and water vapor. The temperature of the methanol vapor and the water vapor are measured by the temperature sensor 77 and flow into the reforming reactor 1.

On the other hand, the compressor 2 which is an air supply device
Compresses the air taken in via a filter (not shown) and supplies the compressed air to the air electrode 12a of the fuel cell main body 12, and the reforming reactor 1, CO (one The carbon oxide) remover 8 is supplied. A temperature sensor 4 and a flow rate sensor 5 are provided in front of an air flow rate adjusting valve 6 that adjusts the flow rate of air flowing into the reforming reactor 1 from the compressor 2.

The reforming reactor 1 containing the reforming catalyst is
Using methanol vapor and steam supplied from the evaporator 3 and compressed air supplied from the compressor, hydrogen and carbon dioxide (exothermic reaction) and hydrogen reforming reaction (endothermic reaction) of methanol are carried out. CO ₂ ) is produced and the reformed gas containing these is sent to the CO remover 8. The reforming reactor 1 is a shift reaction integrated type that burns CO generated by the reforming reaction and the partial oxidation reaction, but some CO is present in the hydrogen-rich reformed gas output from the reforming reactor 1. include. Further, the reforming reactor 1 is equipped with a temperature sensor 9 for measuring the temperature inside thereof.

The CO remover 8 uses the air from the compressor 2 to selectively oxidize residual CO in the reformed gas sent from the reforming reactor 1 (exothermic reaction), and harmless the fuel cell main body 12. Change to CO ₂ .

The flow rate sensor 24 measures the flow rate of the reformed gas from which CO has been removed by the CO remover 8, and the temperature sensor 11
The temperature is measured at the hydrogen electrode 12b of the fuel cell body 12
Is supplied to the entrance. In the present embodiment, the outlet gas temperature of the CO remover 8 is adjusted by the cooling device (not shown) so that the temperature sensor 11 reaches the control temperature.

On the other hand, the air compressed by the compressor 2 is supplied to the inlet of the air electrode 12a of the fuel cell body 12. Then, in the fuel cell main body 12, electricity is generated by an electrochemical reaction using hydrogen in the reformed gas and oxygen in the air, and DC power is supplied to the load 26 described later.

A cooling liquid passage (not shown) is provided in the fuel cell main body 12, and the circulation of the refrigerant is controlled by a cooling device (not shown) so that the temperature of the fuel cell main body 12 is maintained at an appropriate temperature for power generation. Has been done.

At the outlet of the air electrode 12a of the fuel cell main body 12, there is provided a pressure sensor 15 for measuring the pressure of the fuel cell main body 12 and a pipe connected to the combustor 17 via the pressure regulating valve 13. Similarly, at the outlet of the hydrogen electrode 12b, a pressure sensor 16 for measuring the pressure thereof and a pipe connected to the combustor 17 via the pressure adjusting valve 14 are provided. Pressure control valve 1
The ECUs 3 and 14 are controlled by the ECU 40, which will be described later, so that the pressure of the air electrode 12a and the pressure of the hydrogen electrode 12b measured by the pressure sensors 15 and 16 respectively become control target values.

The combustor 17 is supplied with the exhaust air containing oxygen remaining supplied from the air electrode 12a and the exhaust reformed gas containing hydrogen remaining supplied from the hydrogen electrode 12b, and burns the hydrogen and oxygen. The exhaust gas having a high temperature is generated and supplied to the evaporator 3 as a heat source, while the surplus exhaust gas is discharged to the outside of the vehicle. Further, the combustor 17 is provided with a temperature sensor 18 that detects the temperature thereof.

The ECU 40, which is the control device of the fuel reformer according to the present invention, includes a control temperature generating section 41, a target value generating section 42 for generating an air target flow rate and a reformed gas target flow rate,
A non-interference control unit 43 that performs non-interference control so that the air flow rate of each unit to which air is supplied from the compressor 2 becomes a target value, and a temperature control unit 4 that controls the temperature of the reforming reactor 1.
4 and the measurement position temperature which is the temperature at the mounting position of the temperature sensor 9 which is the temperature estimating means and the temperature measuring means which estimates the peak temperature which is the highest temperature in the reforming reactor 1 based on the operating conditions. A temperature estimating unit 45 as a measuring position temperature estimating means, and a deterioration estimating means for estimating a deterioration estimated value indicating the degree of deterioration of the reforming reactor 1 based on a deviation between the measured position temperature estimated value and the temperature measured value. And the deterioration estimation unit 46. This ECU 40 is, for example,
It is realized by a microcomputer having a CPU and a peripheral interface.

In the control temperature generation unit 41, the required air flow rate and the required fuel flow rate are set so that the outlet gas temperature detected by the temperature sensor 18 provided at the outlet of the combustor 17 becomes the target gas temperature. calculate.

The required air amount calculated by the control temperature generator 41 is input to the target value generator 42 to calculate the total air flow rate required for the entire fuel cell system.

The target value generator 42 calculates the target flow rate of each of the reforming reactor 1, the CO remover 8 and the air electrode 12a to which the air is supplied from the compressor 2, and the air which is the total of these target flow rates. To calculate the target total flow rate. The target value generation unit 42 also calculates the target flow rates of methanol and water that are raw fuels to be supplied to the evaporator 3.

The non-interference control section 43 includes the reforming reactor 1, CO
The opening degree of the air flow rate control valve 6, the opening degree of the air flow rate control valve 10, and the driving force of the compressor 2 are controlled so that the air flow rates at the remover 8 and the air electrode 12a reach the respective target values, and the respective air flows are controlled. Non-interference control is performed so that the flow rate is not affected by other air flow rates.

In the non-interference control section 43, the target value generation section 42
The target total flow rate of air required for the entire fuel cell system calculated in step 3 is received, and the compressor 2 is controlled so that the total of the flow rates of air measured by the respective flow rate sensors becomes the target total flow rate. In this embodiment, the rotation speed of the compressor is controlled by the non-interference control unit 43 so as not to interfere with the control of other flow rates and pressures.

Regarding the air flow rate to the air electrode 12a of the fuel cell body 12, the total air flow rate is controlled to a target value, and the air flow rate to the reforming reactor 1 and the air flow rate to the CO remover 8 are the target values. Therefore, the target value can be controlled without installing a valve for controlling the air flow rate of the air electrode 12a of the fuel cell body 12.

The pressure on the air electrode 12a side and the pressure on the hydrogen electrode 12b side of the fuel cell body 12 are controlled by the non-interference control section 43. The target pressure on the air electrode 12a side and the target pressure on the hydrogen electrode 12b side are calculated by the target value generation unit 42, and the target values are input to the non-interference control unit 43, and the non-interference control unit 43 causes the pressure sensor to operate. The opening of the pressure regulating valve 13 is controlled so as not to interfere with other air flow rate and pressure control so that the pressure on the side of the air electrode 12a measured at 15 becomes a target value.

Hydrogen electrode 12 measured by pressure sensor 16
The opening of the pressure regulating valve 14 is controlled so as not to interfere with other air flow rate and pressure control so that the pressure on the b side becomes a target value.

The temperature controller 44 is a temperature controller of the reforming reactor 1. The flow rate of the air to be supplied to the reforming reactor 1 is calculated by feedback control so that the peak temperature of the reforming reactor 1 estimated by the temperature estimating unit 45 becomes the target control temperature.

Further, the temperature control unit 44 includes the target value generation unit 42.
Therefore, the target value of the air flow rate to be supplied to the reforming reactor 1 is received. In the temperature control unit 44, this is added as a feedforward term to the flow rate of air to be supplied to the reforming reactor 1 obtained by the feedback control in the temperature control unit 44.

The target value of the flow rate of air to be supplied to the reforming reactor 1 calculated in this way is sent to the non-interference control section 43, and the non-interference control section 43 controls the air flow rate of the reforming reactor 1. In order to do so, the opening degree of the air flow control valve 6 is controlled.

The temperature estimating section 45 estimates the peak temperature and the measured position temperature in the reforming reactor 1 by using the temperature in the reforming reactor 1 as a model. For temperature estimation, the target value generator 4
Operate the target flow rate of the raw fuel (methanol vapor and water vapor) calculated in 2, the temperature of the raw fuel measured by the temperature sensor 7, the air flow rate measured by the flow rate sensor 5, and the air temperature detected by the temperature sensor 4. Input as state, reforming reactor 1
A temperature model function for outputting the internal peak temperature and the measured position temperature according to the operating conditions is stored in advance, and the temperature of the reforming reactor 1 is estimated with reference to this temperature model function.

Next, the properties of the temperature model function used in this embodiment will be described.

When the air flow rate is increased, the partial oxidation reaction in the reforming reactor becomes active, so that the temperature inside the reforming reactor rises, and conversely, when the air flow rate is reduced, the temperature decreases.

When the temperature of the air rises, the amount of heat carried into the air also increases, so the temperature inside the reforming reactor rises,
On the contrary, when the temperature of the air decreases, the temperature inside the reforming reactor decreases.

When the flow rate of the raw fuel is increased (however, the ratio of water and methanol is constant), the steam reforming reaction which is an endothermic reaction in the reforming reactor becomes active, so that the temperature in the reforming reactor decreases, On the contrary, if it is decreased, the temperature rises.

Further, when the temperature of the raw fuel rises, the amount of heat carried into the raw fuel increases, so the temperature inside the reforming reactor rises, and conversely, when the temperature of the raw fuel falls, the temperature inside the reforming reactor falls. .

The same operating conditions (amount of raw fuel supplied to the reforming reactor, temperature of raw fuel, amount of air, temperature of air)
However, as the deterioration of the reforming reactor 1 with time progresses, the peak temperature decreases and the position where the peak temperature occurs changes so as to approach the outlet side of the reforming reactor.

As described above, since the temperature in the reforming reactor 1 is closely related to the flow rate and temperature of the raw fuel and the air flow rate and temperature, the temperature in the reforming reactor is obtained from data obtained in advance by experiments. It can be stored in advance as a table or a function based on multivariate analysis.

The temperature estimating means of the present invention is the temperature estimating section 45 for estimating the temperature of the reforming reactor 1 and has the following functions.

(1) The temperature estimating section 45 estimates the temperature of the reforming reactor 1 based on the operating conditions, and calculates an estimated temperature value.

(2) The temperature estimating section 45 acquires the outside air temperature from the outside air temperature sensor 35 and corrects the estimated temperature value.

The deterioration estimating means of the present invention is the deterioration estimating unit 46 which estimates the deterioration of the reforming reactor 1 and has the following functions.

(1) The deterioration estimating unit 46 estimates the deterioration state based on the deviation between the temperature measured value of the reforming reactor 1 estimated by the temperature estimating unit 45 and the temperature measured value actually measured by the temperature sensor 9. To do.

(2) The deterioration estimating unit 46 detects the deterioration state of the reforming reactor 1, and when the abnormality judgment is made, informs the driver of the deterioration state by the information providing device 32. In the present embodiment, the information providing device 32 is a lamp provided on the instrument panel, and when the abnormality in the deterioration state is detected, the lamp is turned on to provide the abnormality detection information to the driver.

(3) The deterioration estimating unit 46 compares the sum of the power generation state detecting device 34 and the charging state detecting device 31 with the voltage calculated from the required torque detecting device 33 to estimate abnormal deterioration. In the present embodiment, the required torque detection device 33 has a linear relationship with the accelerator pedal, and the accelerator pedal stroke is calculated as the driver required torque.

The load 26 is a load connected to the fuel cell main body 12, and a charger 27 and an inverter 2 for charging a secondary battery 29 described later with surplus electric power of the fuel cell main body 12.
8. A secondary battery 29 is connected.

The inverter 28 can convert the direct current power supplied from the fuel cell main body 12 or the secondary battery 29 into alternating current power to drive the drive motor 30 and use it as power for running the vehicle.

The charge state detection device 31 detects the charge state of the secondary battery 29 by the charger 27. In this embodiment, it is a voltmeter.

Next, referring to the flowchart of FIG.
The operations of the temperature estimating unit 45 and the deterioration estimating unit 46 will be described in detail.

First, in step S1, it is determined whether or not the fuel reforming system is in the initial startup state.

In this embodiment, the catalyst of the reforming reactor 1 of FIG. 1 is in the active temperature range, and the CO remover 8
Based on the condition that the catalyst is in the activation temperature range, if the above two conditions are not satisfied even after the start, it is judged that the initial state is the start and the deterioration is not estimated.

Next, in step S2, it is determined whether or not the required torque of the driver detected by the required torque detection device 33 is in a transient state. In the present embodiment, when the rate of change of the driver request torque is equal to or greater than a certain value, the transient state is set, and the rate of change is calculated by using the differential value of the accelerator pedal stroke amount as the rate of change.

In step S3, operating conditions including the amount of raw fuel (methanol and water) supplied to the reforming reactor 1, the temperature of the raw fuel, the amount of air, and the temperature of the air, and the reforming reactor 1 are provided. Measured value of the temperature sensor 9 and the outside air temperature sensor 35
Read the measured value of outside temperature by.

In step S4, the temperature estimation unit 45 causes the peak temperature, which is the highest temperature in the reforming reactor 1, and the measured position temperature, which is the temperature at the mounting position of the temperature sensor 9, based on the previously read operating conditions. Calculate the estimated temperature value of. In order to calculate this temperature estimated value, a temperature distribution map of the reforming reactor 1 as shown in FIG. 3 is prepared for each operating condition as a data table obtained in advance by experiments.

In step S5, the estimated temperature value calculated in step S4 is corrected with reference to the measured value of the outside air temperature. In order to calculate the correction value used for this correction, a map as shown in FIG. 4 for obtaining the temperature correction value from the position inside the reforming reactor 1 and the outside air temperature is previously obtained by experiment and stored. The configuration of the map shown in FIG. 4 is such that the higher the outside air temperature, the higher the correction temperature, and the lower the outside temperature, the lower the correction temperature. In addition, the correction map depends on the temperature distribution of the reforming reactor 1.

In step S6, a moving average of the past 100 times of the deviation between the measured position temperature estimated value obtained in step S5 and the temperature measured value of the temperature sensor 9 is calculated, and this is set as err.

In steps S10 and S16, a branch is made to a flow for determining whether abnormal deterioration, aged deterioration, or normal is based on err calculated in S6.

In this embodiment, as shown in FIG.
By comparing two predetermined values (threshold values) of nst2 and const3, a processing routine for abnormal deterioration, aged deterioration, and normality determination is branched.

In step S10, | err |> con
Whether or not st3 is determined. If the condition of step S10 is satisfied, it is determined that the deterioration is abnormal and step S20 is performed.
Go to. If the condition of step S10 is not satisfied, the process proceeds to step S11.

In step S11, the required cell voltage Vn calculated by the required torque detection device 33 of FIG. 1 and the actual cell voltage Vr of the fuel cell main body 12 detected by the power generation state detection device 34 or the charging state detection device 31 are read.

In step S12, the difference between the required cell voltage Vn and the actual cell voltage Vr is compared with a certain value const5, and it is determined from the magnitude relationship whether or not there is abnormal deterioration.
If the difference between the required cell voltage Vn and the actual cell voltage Vr is c
If the value is larger than onst5, it is determined as abnormal deterioration. In the present embodiment, const5 = (Vr + Vn) /
It was set to 2 * 0.5.

In step S13, it is determined that abnormal deterioration has occurred, and the abnormal deterioration judgment result is stored in the internal processing of the ECU 40.

In step S14, since the system is judged to be abnormal at the time of step S12, the amount of raw fuel supplied to the reforming reactor 1 is limited. In the present embodiment, FIG.
As shown in, the upper limit value of the raw fuel to be supplied is reduced as the err increases. In addition, in the present embodiment, the required cell voltage Vn is changed so that the required cell voltage Vn does not exceed the actual cell voltage Vr, and a limitation is imposed so as to supply the raw fuel commensurate with the changed required cell voltage. As a result, the target flow rate is changed so that the fuel control device 22 and the water flow rate control device 20 limit the flow rates of methanol and water that are raw fuels to be supplied to the evaporator 3.

In step S15, the information providing device 32 is operated to provide the driver with information about abnormal deterioration of the reforming reactor 1. In this embodiment, the information providing device 32 provides the deterioration information of the fuel reformer by turning on the lamp provided in the instrument panel in front of the driver's seat.

In step S16, | err |> con
It is determined whether or not st2. If this determination is Yes, it is determined in step S17 that the value of err is within the range of aged deterioration, and the aged deterioration determination result is stored in the ECU 40 internal processing.

Then, in step S18, the temperature estimation model is switched to the temperature estimation model for aging deterioration. In the temperature distribution map of the reforming reactor 1 of FIG. 3 which is the temperature estimation model, the peak temperature of the reforming reactor 1 becomes lower as the err value becomes larger, and the position in the reforming reactor becomes the peak temperature. Is a map that moves from the entrance side to the exit side.

If the determination in step S16 is no, e
Assuming that the rr value is in the normal range, the normal determination result is stored in the internal processing of the ECU 40, and the process returns.

In step S20, since the immediately previous determination of the err value was abnormal deterioration, it is judged as abnormal deterioration and EC
The abnormal deterioration determination result is stored in U40 internal processing.

In step S21, as in step S14, since the system is judged to be abnormal at the time of step S10, the amount of raw fuel supplied to the reforming reactor 1 is limited. The specific limiting method is the same as that described in step S14.

In step S22, as in step S15, the information providing device 32 is operated to provide the driver with information about abnormal deterioration of the reforming reactor 1. In this embodiment,
The information providing device 32 provides the deterioration information of the fuel reformer by turning on a lamp provided in the instrument panel in front of the driver's seat.

The temperature estimation unit 45 of the present embodiment uses the data table for temperature estimation, but the present invention is not limited to this, and calculation is performed using a function that models the temperature change of the reforming reactor 1 as follows. It is also possible to calculate the correct peak temperature after deterioration by performing the deterioration determination and changing the constant of the function of the model according to the deterioration. Further, in each of the following formulas, "*" is used as a multiplication symbol to make the distinction from X clear.

[0096]

[Equation 1] (∂ (T) / ∂t + (u1 + u2 + u3) * ∂ (T) / ∂z) * (cp * p) = k1 * H1 + K2 * H2-U * A * (T -Tw) (1) T: Temperature in reforming reactor [K] u1: Air velocity [m / s] Air velocity is output of flow sensor 5 [m3 / s] / cross-sectional area of pipe [m2] ]]

U2: Methanol flow rate [m / s]. In the case of methanol, it can be determined in the same manner.

U3: Flow rate of water. In the case of water, the same can be calculated.

However, since the flow rate sensor for methanol and water is not used in this embodiment, the target value is used.

H1: heat of reaction between water and methanol (endotherm),
-49500 [J / mol] H2: Heat of reaction between oxygen and methanol (exothermic), 18960
0 [J / mol] p: Average density [kg / m3] cp: Average heat capacity [J / (kg * K)] k1 = A1 * EXP (-E1 / RT) * (CH3OH) * (H2O) k2 = A2 * EXP (-E2 / RT) * (CH3OH) * (O2) ^0.5 E1 and E2 are activation energy constants, and A1 and A2 are appropriate constants called frequency coefficients.

[CH3OH], [H2O], and [O2] represent concentrations [mol / m3].

R: gas constant, 8.314 [J / (mol * K)] U: heat transfer coefficient [J / (K * s * m2)] A: heat transfer area of wall [m2] Tw: reactor Outside air temperature [K] (In this embodiment, the outside air temperature is not measured, so it is set to a fixed value.) If outside air temperature is being measured, that value may be used.

Z represents space and t represents time.

The spatial derivative is deleted in order to calculate the equation (1) by the microcomputer. Therefore, in this embodiment, the first-order backward difference is used. Also, the entire reforming reactor (from the inlet to the outlet)
Is set to L [m], and this is divided into appropriate N sub-regions. When the length of one sub-region is Δz, the following equation (2) is obtained.

[0105]

[Equation 2] Δz = L / N (2) The first-order backward difference is given by the following equation (3).

[0106]

(3) (∂ (T) / ∂z) _n = (T _n -T _n-1 ) / Δz (3) The subscript n is the nth sub-region of the N sub-regions. Indicates that there is.

When the equation (1) is expressed using the equation (2), the following equation (4) is obtained.

[0108]

(4) (d (T _n ) / dt + (u1 + u2 + u3) * (T _n -T _n-1 ) / Δz) * cp * p = k1 * H1 + k2 * H2-U * A * (T _n -Tw) [J / s] (4) In the present embodiment, when n = 1, T0 is the average temperature of air, methanol, and water. The output of the temperature sensor 7 was used because the temperature of the air is the output of the temperature sensor 4 and the mixture of methanol and water is steam. Equation (3) is an energy balance equation, which can be used as an equation representing the change in temperature if integrated.

In order to calculate the equation (3),

[Equation 5] k1 = A1 * EXP (-E1 / RT _n ) * (CH3OH) * (H2O) k2 = A2 * EXP (-E2 / RT _n ) * (CH3OH) * (O2) ^0.5 needs to be calculated. is there.

Since k1 and k2 can be calculated if the concentrations are known,
The concentration is calculated by the following formula.

[0111]

[Formula 6] d (CH3OH _n ) / dt + u1 * (CH3OH _n -CH3OH _n-1 ) / Δz = -A1 * EXP (-E1 / RT _n ) * (CH3OH _n ) * (H2O _n ) d (H2O _n ) / dt + u2 * (H2O _n -H2O _n-1 ) / Δz = -A1 * EXP (-E1 / RT _n ) * (CH3OH _n ) * (H2O _n ) d (O2 _n ) / dt + u3 * (O2 _n- O2 _n-1 ) / Δz = -A2 * EXP (-E2 / RT _n ) * (CH3OH) * (O2) ^0.5 (5) In the present embodiment, the raw fuel methanol and water are used. Since the flow rate sensor for measuring the flow rate is not provided, each target value calculated by the target value generation unit 42 was used. If a sensor that measures the flow rate of raw fuel is installed,
You should use those values.

The temperature estimation calculation may be performed for the entire region of the reforming reactor 1, but more efficiently, the region where the peak temperature will occur is predicted in advance according to the operating conditions, and this If the area is near the inlet of the reforming reactor 1,
Even if the above equations (4) and (5) are used, the number of calculations does not increase so much, and therefore the equations can be used as they are.

However, when the peak temperature region is far from the inlet of the reforming reactor 1 and the number of calculations is large, first,
The rough Δz (formula 2) is calculated up to the region set by the peak temperature region setting means by using the above formulas (4) and (5).

Next, in the peak temperature region, if the above calculation result is used as the initial value and the finely divided Δz (Equation 2) is calculated using the above Equations (4) and (5), a small amount of computation is required. You can make an accurate estimation with. It should be noted that the calculation may be performed with a rough Δz, but since an error becomes large, it is better to calculate with a fine Δz in the peak temperature region. When estimating the temperature at the position where the temperature sensor 9 is provided, the same method as described above may be used.

[Brief description of drawings]

FIG. 1 is a system configuration diagram illustrating a configuration of a fuel cell system to which a control device for a fuel reformer according to the present invention is applied.

FIG. 2 is a flowchart illustrating an operation of estimating deterioration of a reforming reactor.

FIG. 3 is a diagram showing an example of a temperature map in the reforming reactor referred to in estimating the temperature of the reforming reactor.

FIG. 4 is a diagram for explaining temperature correction of the reforming reactor according to the outside air temperature.

FIG. 5 is a diagram illustrating a deterioration determination criterion based on a deviation between an estimated temperature value of a reforming reactor and a measured temperature value.

FIG. 6 is a diagram illustrating a relationship between an upper limit of a raw fuel supply amount due to a deviation between an estimated temperature value of a reforming reactor and a measured temperature value.

[Explanation of symbols]

1 ... Reforming reactor 2 ... Compressor 3 ... Evaporator 4 ... Temperature sensor 5 ... Flow rate sensor 6 ... Air flow control valve 7 ... Temperature sensor 8 ... CO remover 9 ... Temperature sensor 10 ... Air flow control valve 11 ... Temperature sensor 12 ... Fuel cell body 13 ... Pressure control valve 14 ... Pressure control valve 15 ... Pressure sensor 16 ... Pressure sensor 17 ... Combustor 18 ... Temperature sensor 20 ... Water flow controller 21 ... Water tank 22 ... Fuel control device 23 ... Fuel tank 24 ... Flow rate sensor 32 ... Information providing device 35 ... Outside air temperature sensor 40 ... ECU 41 ... Management temperature generation unit 42 ... Target value generator 43 ... Non-interference control unit 44 ... Temperature control unit 45 ... Temperature estimation unit 46 ... Deterioration estimation unit

Claims (11)

[Claims] 1. A fuel reformer control device for reforming raw fuel to produce a fuel gas containing hydrogen, wherein the temperature measuring means measures the temperature in a reforming reactor containing a reforming catalyst. A temperature estimation means for estimating at least the highest peak temperature of the temperatures in the reforming reactor based on the operating conditions of the fuel reformer; and a temperature estimation value estimated by the temperature estimation means. A fuel reformer control device comprising: a deterioration estimating unit that estimates a degree of deterioration of the reforming reactor based on a deviation from a temperature measurement value obtained by the temperature measuring unit. 2. The temperature estimation means estimates a temperature at a mounting position of the temperature measurement means in the reforming reactor, and a measurement position temperature estimation estimated by the measurement position temperature estimation means. And a correction unit that corrects the temperature estimated value based on a deviation between the value and the temperature measured value obtained by the temperature measuring unit, wherein the deterioration estimating unit includes the measured position temperature estimated value and the temperature measured value. The control device of the fuel reformer according to claim 1, wherein the degree of deterioration of the reforming reactor is estimated based on the deviation. 3. The temperature estimating means has a plurality of temperature characteristic maps storing temperature characteristics of the reforming reactor according to operating conditions and the degree of deterioration, and the correcting means estimates the measured position temperature. The fuel reformer control device according to claim 2, wherein selection of the temperature characteristic map is changed based on a deviation between a value and the temperature measurement value. 4. The control device for a fuel reformer according to claim 1, wherein the deterioration estimating unit does not perform deterioration estimation in an initial state of startup. 5. The fuel reformer control device according to claim 1, wherein the deterioration estimating unit does not perform deterioration estimation during an operating transient state. 6. An outside air temperature measuring means for measuring the temperature of outside air, wherein the temperature estimating means corrects the estimated temperature value according to the outside air temperature. A control device for a fuel reformer according to the item. 7. When the deviation is within a range of a first predetermined value or more and a second predetermined position or less, the deterioration estimating unit determines that the deterioration is due to aging, and the correcting unit estimates the temperature when the temperature is normal. The control device for a fuel reformer according to claim 2, wherein the method is switched to a method for estimating temperature at the time of deterioration over time. 8. The fuel reformer control device according to claim 2, wherein when the deviation exceeds a second predetermined value, the deterioration estimating unit determines that the deterioration is abnormal. 9. The control device for a fuel reformer according to claim 8, further comprising notification means for notifying an abnormality of the fuel reformer when it is judged as abnormal deterioration. 10. A voltage detector for detecting an actual cell voltage of a fuel cell that generates electric power using the fuel gas reformed by the fuel reformer, and a request for calculating a required cell voltage according to a required power for the fuel cell. Voltage calculating means and notifying means for notifying an abnormality of the fuel reformer if the difference is not more than a second predetermined value and the difference between the actual cell voltage and the required cell voltage is not less than a third predetermined value. The control device for the fuel reformer according to claim 2, further comprising: 11. The amount of the raw fuel supplied to the reforming reactor is controlled according to the degree of deterioration by the deterioration estimating means. Fuel reformer control device.