JP6512043B2 - Fuel reforming method and fuel reforming apparatus - Google Patents

Description

  The present invention relates to a fuel reforming method and a fuel reforming apparatus for reforming a mixture of fuel and air by a reforming catalyst.

At present, in the technical field related to fuel reforming of an internal combustion engine, there is a technique of correcting the amount of reforming fuel based on the concentration of CO ₂ or the concentration of H ₂ O after fuel reforming. For example, in a fuel reformer and its operating method disclosed in Patent Document 1, an internal combustion engine is a fuel reformer that reforms a mixture of hydrocarbon fuel and air by a reforming catalyst, an ECU, and Equipped with The fuel reformer includes a reforming reaction unit in which a reforming catalyst is disposed, and a CO ₂ sensor that detects the concentration of CO ₂ contained in the fluid that has flowed out of the reforming reaction unit. The ECU corrects the amount of hydrocarbon fuel supplied to the reforming reaction part so that the CO ₂ concentration detected by the CO ₂ sensor falls within a predetermined range, thereby carbonizing the carbon dioxide supplied to the reforming reaction part The ratio O / C of oxygen atoms in air to carbon atoms in hydrogen-based fuels is made to fall within a range of approximately 1 to a value slightly over 1.

JP 2005-247672 A

  However, in the above-mentioned existing technology, since the amount of reformed fuel is corrected based on the generated component after fuel reformation, there is a possibility that the catalytic reaction affects and the accuracy is lowered.

An object of the present invention is to provide a fuel reforming method and a fuel reforming apparatus capable of highly accurate correction of the amount of reformed fuel .

  In the fuel reforming method and the fuel reforming device according to one aspect of the present invention, at least a portion of the fuel is converted to hydrogen by a chemical reaction on the reforming catalyst in the fuel reformer in order to solve the above problems. When the thermal efficiency of the internal combustion engine is improved by reforming and mixing the reformed gas containing hydrogen with the intake air and burning it in the internal combustion engine, the gas before and after each of the injectors injecting the fuel to the reforming catalyst The amount of state is detected, the fuel injection amount of the injector is estimated based on the change of the state amount of gas before and after the injector, and the fuel injection amount of the injector is corrected based on the estimated fuel injection amount.

  According to one aspect of the present invention, the fuel injection amount is estimated based on the change in the state amount of gas before and after the injector, and the fuel injection amount to the fuel reformer is estimated based on the estimated fuel injection amount. The amount of reformed fuel can be corrected before reforming the fuel.

It is a figure showing an example of composition of a fuel reformer concerning one embodiment of the present invention. And the reaction temperature, and hydrogen (H ₂₎ generated concentration is a diagram showing the relationship between carbon deposition region. It is a figure which shows the relationship between the 1st arrangement | positioning and shape of an injector, and fuel distribution and temperature distribution in the catalyst container of a fuel reformer. It is a figure which shows the relationship between the 2nd arrangement | positioning and shape of an injector, and fuel distribution and temperature distribution in the catalyst container of a fuel reformer. It is a figure which shows the relationship between the 3rd arrangement | positioning and shape of an injector, and fuel distribution and temperature distribution in the catalyst container of a fuel reformer. It is a figure which shows the relationship between the 4th arrangement | positioning and shape of an injector, and fuel distribution and temperature distribution in the catalyst container of a fuel reformer. It is a figure which shows the relationship between the 5th arrangement | positioning and shape of an injector, fuel distribution in the catalyst container of a fuel reformer, and temperature distribution. It is a timing chart which shows the relation between the amount of deposit adhesion and the transition time to the injector cleaning mode. It is a flowchart which shows the flow of the process regarding estimation of the amount of depot adhesion. It is a flowchart which shows the flow of the process regarding feedback control of the fuel injection quantity of an injector. It is a flow chart which shows the flow of the 1st processing about shift judging control to injector washing mode. It is a flow chart which shows the flow of the 2nd processing about shift judging control to injector washing mode.

Next, an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and different from real ones. Therefore, specific components should be determined in consideration of the following description.
In addition, the embodiments described below illustrate apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention includes the shape, structure, arrangement, and the like of components. It does not specify the following. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.
In the following detailed description, numerous specific details are set forth to provide a thorough understanding of an embodiment of the present invention. However, it will be apparent that one or more embodiments may be practiced without such specific details. Besides, well-known structures and devices are illustrated schematically in order to simplify the drawings.

Embodiment
Hereinafter, a fuel reformer according to an embodiment of the present invention will be described.
(Fuel reformer)
A fuel reformer according to an embodiment of the present invention controls an exhaust gas recirculation system as shown in FIG. In the exhaust gas recirculation system, an intake passage 2 for passing intake gas is disposed upstream of an internal combustion engine 1 (engine) comprising, for example, a spark-ignition gasoline engine of a four-stroke cycle.

The intake passage 2 is opened to the outside through an air intake (not shown) which is an intake port, and takes in external air as intake gas from the air intake. An air flow meter 3 for measuring the inflow of intake gas is disposed around or downstream of the air intake. A throttle chamber 4 incorporating an electronically controlled throttle valve for controlling the inflow of intake gas is disposed downstream of the air flow meter 3. A turbocharger 5 is disposed downstream of the throttle chamber 4 to increase the pressure of the intake gas to the atmospheric pressure or higher. On the downstream side of the turbocharger 5, an intake-side hydrogen sensor 6 for measuring the concentration of hydrogen (H ₂ ) in the intake gas is disposed. The internal combustion engine 1 is disposed downstream of the intake side hydrogen sensor 6.

  Here, the internal combustion engine 1 has, for example, a direct injection type configuration, and is provided with an electronically controlled fuel injection device 1a for injecting fuel (gasoline) supplied from the fuel tank 7 into the cylinders for each cylinder. The intake passage 2 is branched for each cylinder of the internal combustion engine 1 as an intake manifold for equalizing the intake distribution to each cylinder of the internal combustion engine 1 at a connection portion with the internal combustion engine 1. The fuel injection amount of the fuel injection device 1a is feedback-controlled based on a detection signal of the intake side hydrogen sensor 6 or the like. Further, in the internal combustion engine 1, an in-cylinder pressure sensor 1b for measuring the pressure in the crankcase and a PCV valve (not shown) serving as a vent for escaping the pressure in the crankcase are disposed.

Further, on the downstream side of the internal combustion engine 1, an exhaust passage 8 for passing the exhaust gas is disposed. The exhaust passage 8 combines multiple flow paths of the exhaust gas of the internal combustion engine 1 into one as an exhaust manifold on the downstream side of the internal combustion engine 1 (not shown). An exhaust side A / F (air-fuel ratio) sensor 9 for measuring how rich or lean the air-fuel ratio of the exhaust gas is (rich / lean) is disposed in the exhaust passage 8. On the downstream side of the exhaust side A / F sensor 9, an exhaust catalyst 10 (exhaust purification device) such as a manifold catalyst or an underfloor catalyst is disposed. On the downstream side of the exhaust catalyst 10, an exhaust side oxygen sensor 11 for measuring the concentration of oxygen (O ₂ ) in the exhaust gas is disposed. An exhaust silencer (not shown) is disposed downstream of the exhaust side oxygen sensor 11. The exhaust passage 8 is opened to the outside through the exhaust silencer, and the exhaust gas passing through the exhaust passage 8 is discharged to the outside.

  Further, in the exhaust gas recirculation system, a circulation passage 12 connecting the intake passage 2 and the exhaust passage 8 is disposed. The circulation passage 12 branches from the exhaust passage 8 downstream of the exhaust side A / F sensor 9 and upstream of the exhaust catalyst 10, merges with the intake passage 2 on the upstream side of the supercharger 5, and from the exhaust passage 8 to the intake passage. 2) A part of the exhaust gas is passed as EGR (Exhaust Gas Recirculation) gas. An EGR temperature sensor 13 for measuring the temperature of the EGR gas is disposed in the circulation passage 12. On the downstream side of the EGR temperature sensor 13, an electronically controlled reforming fuel injection device 14 for injecting the fuel supplied from the fuel tank 7 into the circulation passage 12 is disposed. On the downstream side of the reforming fuel injection device 14, a fuel evaporator 15 is disposed which evaporates the fuel injected into the circulation passage 12 into fuel evaporated gas. On the downstream side of the fuel evaporator 15, a fuel reformer 16 is disposed which reforms a mixture of fuel evaporated gas and air by a reforming catalyst.

For example, the fuel reformer 16 reacts a fuel evaporative gas with water vapor (H ₂ O) at a predetermined temperature using a reforming catalyst (a platinum catalyst or the like) to generate hydrogen (H ₂ ) gas having a high concentration. Produces (steam reforming). Although carbon monoxide (CO) is generated with fuel reforming, carbon monoxide (CO) in the hydrogen (H ₂ ) gas will reduce the performance of the reforming catalyst if carbon monoxide (CO) is present. Need to reduce the concentration of Therefore, carbon monoxide (CO) and steam (H ₂ O) are further reacted to form hydrogen (H ₂ ) and carbon dioxide (CO ₂ ) (shift reaction). Then, the remaining carbon monoxide (CO) is adsorbed on the surface of the reforming catalyst to render it harmless. Thus, hydrogen (H ₂ ) is mixed with the EGR gas.

  Here, the fuel reformer 16 has a temperature adjusting device 16 a that adjusts the temperature in the fuel reformer 16, and a reforming temperature sensor 16 b that measures the temperature in the fuel reformer 16.

On the downstream side of the fuel reformer 16, an EGR hydrogen sensor 17 for measuring the concentration of hydrogen (H ₂ ) in the EGR gas is disposed. An EGR cooler 18 for cooling the EGR gas is disposed downstream of the EGR hydrogen sensor 17. On the downstream side of the EGR cooler 18, an EGR A / F sensor 19 is disposed to measure how thick or thin the air-fuel ratio of the EGR gas is. Note that, instead of the EGR A / F sensor 19, an EGR oxygen sensor for measuring the concentration of oxygen (O ₂ ) in the EGR gas may be disposed.

  An EGR valve 20 is disposed downstream of the EGR A / F sensor 19 to adjust the inflow of EGR gas from the exhaust side to the intake side. The circulation passage 12 merges with the intake passage 2 on the downstream side of the EGR valve 20. Thus, the intake gas passing through the intake passage 2 mixes with the EGR gas passing through the circulation passage 12.

  Further, in the exhaust gas recirculation system, an electronic control unit 21 (ECU) is disposed. The electronic control unit 21 includes an in-cylinder pressure sensor 1b, an air flow meter 3, an intake side hydrogen sensor 6, an exhaust side A / F sensor 9, an exhaust side oxygen sensor 11, an EGR temperature sensor 13, a reforming temperature sensor 16b, and EGR hydrogen. The sensor values (measurement values) of the sensor 17 and the EGR A / F sensor 19 are obtained by sensing. Further, the electronic control unit 21 controls the fuel injection unit 1a, the throttle chamber 4, the reforming fuel injection unit 14, the fuel reformer 16, and the EGR valve 20 in accordance with the sensor value and the calculation result based thereon. Details will be described later.

(Correspondence to carbon deposition)
The relationship between the reaction temperature in the catalyst container (case) of the fuel reformer 16, the hydrogen (H ₂ ) generation concentration, and the carbon deposition region will be described with reference to FIG.
In the existing technology, when performing fuel reforming in the catalyst container of the fuel reformer 16, to achieve as even as possible fuel distribution (area F1 in FIG. 2) using a stirrer or the like. Is desired. However, in the existing technology, since the temperature distribution is not taken into consideration, the carbon deposition on the outer peripheral side of the low temperature catalyst container reduces the performance due to carbon deposition, and the radial center axis of the high temperature catalyst container There is a problem that fuel is insufficient and sufficient reforming can not be performed.

  Therefore, in the present embodiment, the fuel distribution is biased to the region where the catalyst temperature is high (region F2 in FIG. 2), so that the temperature distribution when viewed from the radial cross section of the reforming catalyst due to heat radiation from the catalyst container. However, as it approaches the radial center axis of the catalyst container, the height is higher, and the distance from the center axis is lower.

In addition, since the amount of hydrogen (H ₂ ) generated increases as the fuel concentration increases, the amount of hydrogen (H ₂ ) generated increases more than the average distribution of fuel by increasing the fuel concentration as the temperature increases. It is possible to For example, hydrogen (H ₂ ) generation amount is increased by increasing fuel distribution in a region where the catalyst temperature is high.

On the contrary, since carbon is likely to be deposited even at the same fuel concentration as the temperature is lower, deterioration due to carbon deposition can be suppressed by lowering the fuel concentration as the temperature is lower. For example, the lower the reaction temperature, the wider the range of the steam-carbon ratio (S / C) on which carbon deposits, so the fuel distribution in the region where the catalyst temperature is low is reduced.

As described above, in the present embodiment, by matching the fuel with the distribution according to the temperature distribution, it is possible to improve the fuel efficiency by increasing the hydrogen (H ₂ ) generation amount, and to improve the durability of the reforming catalyst accompanying the carbon deposition suppression. Can be

  Further, by making the shape of the catalyst container such that the flow of gas is closer to the central axis in the radial direction, the gas flow rate becomes higher closer to the central axis in the radial direction. Therefore, it is possible to increase the distribution of the gas to be closer to the central axis in the radial direction in accordance with the increase in temperature near the central axis in the radial direction of the reforming catalyst due to the heat radiation from the catalyst container. As a result, the overall heat radiation amount can be suppressed, and the utilization efficiency of the exhaust heat can be improved.

(Fuel distribution and temperature distribution in catalyst container of fuel reformer)
A method of adjusting fuel distribution and temperature distribution in the catalyst container of the fuel reformer 16 will be described with reference to FIGS. 3 to 7.
Since the temperature distribution of the reforming catalyst in the catalyst container of the fuel reformer 16 is higher toward the center, as shown in FIG. 3, the reforming fuel injection device 14 (hereinafter referred to as an injector) is used. The injector is disposed such that the injected fuel is directed to the radial center axis of the reforming catalyst. The central axis of the radial jets of the injectors by arranging in accordance with the central axis of the gas flow, the fuel concentration is higher the closer to the central axis in the radial direction of the catalyst container. Therefore, the fuel concentration can be increased near the central axis in the radial direction in accordance with the temperature near the central axis in the radial direction of the reforming catalyst becoming higher due to the heat released from the catalyst container.

  Further, since the temperature distribution of the reforming catalyst in the catalyst container of the fuel reformer 16 is affected by the gas flow, if the pipe is bent, the radial center of the temperature distribution of the reforming catalyst due to the uneven flow The axis is shifted to the opposite side of the pipe bend. For example, as shown in FIG. 4, when the pipe is bent from the vertical direction to the horizontal direction, the gas flow is caused by inertia and pressure when it is bent from the vertical direction to the horizontal direction along the pipe. Because of the influence of the vertical component, it is not completely horizontal, but is shifted in the vertical direction and bent in the horizontal direction.

  Therefore, as shown in FIG. 4, in consideration of this deviation, the radial central axis of the injection port of the injector is vertically shifted from the radial central axis of the temperature distribution of the reforming catalyst. . As described above, when the gas flow is biased by the piping layout, the layout is such that the spray center is at the maximum value of the flow velocity distribution. As a result, the fuel concentration can be increased near the central axis in the radial direction in accordance with the increase in temperature near the central axis in the radial direction of the reforming catalyst due to heat radiation from the catalyst container.

  Also, in order to form the temperature distribution of the catalyst according to the fuel distribution in the catalyst container of the fuel reformer 16, as shown in FIG. 5, the diameter (crossing area) of the pipe in front of the catalyst container Make it smaller. Furthermore, the specification of the injector is selected to raise the center of the fuel distribution. For example, as shown in FIG. 5A, if the diameter of the pipe in front of the catalyst container is made equal to or larger than the diameter of the catalyst container, the heat radiation from the catalyst container becomes large. Since it is better to raise the central flow rate to suppress heat dissipation from the catalyst container, as shown in FIG. 5 (b), the diameter of the pipe in front of the catalyst container is made smaller than the diameter of the catalyst container, Center the placement of the injectors and select the injector specifications so that the center of the distribution is high. Thus, if the diameter of the pipe in front of the catalyst container is smaller than the diameter of the catalyst container, the heat radiation from the catalyst container can be reduced.

  Further, as shown in FIG. 6, the diameter of the injection port of the injector may be a single injection hole or a diameter close thereto as shown in FIG. 6 so that the fuel concentration in the center becomes high according to the temperature distribution of the reforming catalyst in the catalyst container Use injection holes near the central axis of the direction. Here, as the injector, an injection valve of a spray whose fuel is biased to the center axis in the radial direction like a single injection hole is used.

Further, as shown in FIG. 7, a stirrer (mixer) downstream of the injector is provided for the purpose of promoting the vaporization of the fuel in the catalyst container of the fuel reformer 16 and mixing the fuel and the EGR gas. The injection port of the injector is a spray port for injecting fuel in the form of a mist, and the opening area of the central portion of the spray port of the injector is made relatively larger than the opening area of the peripheral portion. At this time, if fuel is injected when the flow of gas in the circulation passage 12 is in the reverse direction, the fuel flows out to the exhaust passage 8, so that the fuel outflow is set by setting the injection period in which the gas flow is in the forward direction. It can be prevented. The forward flow direction is a direction in which gas flows from the intake passage 2 to the exhaust passage 8 and from the exhaust passage 8 to the intake passage 2 through the circulation passage 12 .

  In addition, since the flow of gas in the catalyst container of the fuel reformer 16 is generated by the pressure difference between the intake and the exhaust, the pressure change of the intake pipe and the exhaust pipe is related to the valve opening timing of each valve. Therefore, by setting the injection timing of the injector based on the opening / closing timing of the exhaust valve and the intake valve, the flow of gas in the catalyst container of the fuel reformer 16 does not reverse even if the rotational speed of the internal combustion engine 1 changes. The state can be realized.

  The gas flow in the catalyst container of the fuel reformer 16 repeats a cycle such as strong forward flow, reverse flow, and stability. Further, in consideration of the injection period and the retention of the injected fuel in the catalyst container, it is necessary to set the injection timing earlier in the backflow period. Therefore, an injection period is set between IVC (intake valve control) in which the flow of gas is in the forward flow direction and EVC (exhaust valve control) of the two combustion cylinders before.

  As described above, in the fuel reforming method according to the present embodiment, the fuel reformer 16 of the internal combustion engine 1 having the fuel reforming catalyst and the injector for supplying the fuel to the catalyst is on the reforming catalyst. The thermal efficiency of the internal combustion engine 1 is improved by reforming at least a part of the fuel (gasoline) into hydrogen by the chemical reaction of (1), mixing the reformed gas containing the hydrogen with the intake air and burning it. The fuel concentration when the fuel and the EGR gas here reach the reforming catalyst has a higher distribution than the central axis in the radial direction of the reforming catalyst.

  At this time, the fuel reformer 16 is disposed on the circulation passage 12 which is a flow passage of the EGR gas. Further, the flow velocity distribution of the EGR gas has a high distribution near the central axis in the radial direction on the axial cross section. Further, in the fuel reformer 16, a point at which the central axis of the injection port of the injector in the radial direction and the upstream end face of the reforming catalyst intersect is on the central axis of the reforming catalyst in the radial direction. Further, in the fuel reformer 16, a point at which the central axis in the radial direction of the injection port of the injector and the upstream end face of the reforming catalyst intersect is on the axis showing the maximum flow velocity on the radial cross section of the reforming catalyst. . In addition, the fuel reformer 16 includes a catalyst container having a structure that holds the catalyst and seals the fuel and the EGR gas, and a pipe that connects the exhaust passage 8 of the internal combustion engine 1 to the catalyst container. Larger than pipe diameter. Furthermore, the fuel reformer 16 includes an agitator (mixer) disposed downstream of the injector for the purpose of promoting vaporization of the fuel and mixing the fuel and the EGR gas, and the injector's injection port sprays the fuel. The opening area of the central portion of the injection hole of the injector is relatively larger than the opening area of the peripheral portion.

(Correspondence to deposit adhesion)
Also, the fuel reformer 16 reforms the fuel supplied from the injector to generate hydrogen (H ₂ ) using the reforming catalyst. As a result, hydrogen (H ₂ ) can be supplied by fuel reforming with a simple configuration. However, the injector is exposed to a high temperature EGR gas for a long time, and the contamination due to the deposition of a deposit (deposition) component in the EGR gas and the formation of a deposit due to carbonization of the fuel in the needle valve sack is generated. At this time, adhesion of the depot to the injector becomes a problem.

  Here, there has been a technology that detects a decrease in the injection amount and then diagnoses the injector's depot, and carries out a cleaning mode (injector cleaning mode) for cleaning the needle valve of the injector. Since the injection amount mode is actually reduced due to the shift to the injector cleaning mode (after the problem occurs), there is an influence on the drivability and fuel efficiency.

  In addition, the depot of the injector can be removed by the increase of the injection amount and the increase of the fuel pressure. Therefore, in the present embodiment, the injection amount is increased before the injection amount decreases (due to problems) due to the adhesion of the depot or the like, or the needle valve of the injector is cleaned by increasing the fuel pressure. It is possible to suppress in advance the decrease in the injection amount and the deterioration of the spray shape.

(Outline of injector cleaning process)
An overview of the injector cleaning process according to the present embodiment will be described with reference to FIG.
The adhesion of the injector needle valve deposits proceeds in the state of exposure to high temperature gas while the fuel injection is stopped, and regresses (or is relieved) in the state of performing the fuel injection. Therefore, since the ratio is correlated with the generation of the needle valve depot, as shown in FIG. 8, the electronic control unit 21 performs the reformation at the time of execution of EGR (EGR ON) and in the fuel reformer 16 ( At the time of reforming ON), when the estimated deposit adhesion amount X becomes equal to or more than the threshold value D, the mode is shifted to the injector cleaning mode (cleaning mode ON).

  However, even when the estimated deposit adhesion amount X becomes equal to or more than the threshold value D when the EGR is performed (EGR ON) and when the reforming by the fuel reformer 16 is performed (reformation ON), the threshold value D is exceeded When the predetermined continuation time (predetermined elapsed time) has not elapsed from the time point, or when the water temperature of the internal combustion engine 1 is equal to or less than the threshold value, the mode does not shift to the injector cleaning mode. As described above, by minimizing the number of transitions of the injector cleaning mode to the minimum necessary number of transitions, deterioration of fuel efficiency and drivability due to excessive injector cleaning can be avoided.

(Estimate of deposit adhesion amount)
The flow of processing relating to the estimation of the deposition amount of depot will be described with reference to FIG.
While the electronic control unit 21 measures the time by adding the timer value (or the counter value) for each unit time (for example, 1 for every one second) and measures the time (step S101 in FIG. 9), the EGR rate> It is determined whether it is 0% (step S102 in FIG. 9). If the electronic control unit 21 determines that the EGR rate> 0% (Yes in step S102 of FIG. 9), it substitutes 1 into the sensitivity coefficient a of the EGR rate (a = 1) (step of FIG. 9) S103). Conversely, if it is determined that the EGR rate is not> 0% (No in step S102 in FIG. 9), 0 is substituted for the sensitivity coefficient a of the EGR rate (a = 0) (step S104 in FIG. 9).

  Next, the electronic control unit 21 determines whether the fuel injection amount of the injector> 0 (step S105 in FIG. 9). If the electronic control unit 21 determines that the fuel injection amount of the injector> 0 (Yes in step S105 of FIG. 9), substitute −1 for the sensitivity coefficient b of the fuel injection amount of the injector (b = −1 ) (Step S106 in FIG. 9). Conversely, if it is determined that the fuel injection amount of the injector is not> 0 (No in step S105 of FIG. 9), 0 (b = 0) is substituted for the sensitivity coefficient b of the fuel injection amount of the injector (FIG. 9) Step S107).

Next, the electronic control unit 21 estimates the adhesion amount of the depot adhering to the needle valve of the injector based on the EGR rate and the fuel injection amount (step S108 in FIG. 9). Here, the electronic control unit 21 estimates the adhesion amount of the depot adhering to the needle valve of the injector using the time integration value obtained by multiplying the EGR rate and the fuel injection amount by the respective sensitivity coefficients (estimated depot adhesion amount Calculation of X). The time integrated value is added when the EGR rate> 0% and the fuel injection amount of the injector = 0. Also, when the EGR rate> 0% and the fuel injection amount of the injector> 0, subtraction is performed. At this time, the addition value increases as the EGR rate increases, and the subtraction value increases as the injection amount increases.

  Next, the electronic control unit 21 determines whether the estimated deposition adhesion amount X exceeds the threshold D (step S109 in FIG. 9). Then, when the estimated deposition adhesion amount X exceeds the threshold D (Yes in step S109 of FIG. 9), the electronic control unit 21 determines whether the injector cleaning mode can be implemented (FIG. 9). Step S110).

If the electronic control unit 21 determines that the injector cleaning mode can be implemented (Yes in step S110 in FIG. 9), the electronic control unit 21 shifts to the injector cleaning mode and performs injector cleaning (step S111 in FIG. 9). . Here, there are the following two modes as the injector cleaning mode.
In the first injector cleaning mode, fuel is injected for a fixed period of time or more (injection amount increase).
In the second injector cleaning mode, the fuel pressure is made higher than usual (fuel pressure increase).
Subsequently, the electronic control unit 21 shifts to the injector cleaning mode and cleans the injector, then resets the timer value (or counter value), and substitutes 0 (X = 0) into the estimated deposition amount X. (Step S112 in FIG. 9).

  On the other hand, when the electronic control unit 21 determines that the injector cleaning mode can not be performed (No in step S110 of FIG. 9), the electronic control device 21 performs the failure diagnosis of the injector and ends the series of processes (FIG. 9). Step S113).

  As described above, in the present embodiment, it is possible to shift to the injector cleaning mode before problems such as deposition of the depot become apparent, so that the influence on the drivability and fuel efficiency can be suppressed.

(Estimate of the amount of combustion injection of the injector)
With reference to FIGS. 10A to 10C, the process flow relating to the estimation of the combustion injection amount of the injector will be described.
The electronic control unit 21 obtains the sensor values of the A / F sensors before and after the injector by sensing (step A1 in FIGS. 10A to 10C) when the fuel reformer 16 does not perform reforming (reforming OFF). , A2). Here, based on the sensor values of the A / F sensors before and after the injector, the “average value of the sensor value difference” which is the base at the time of injection amount zero is calculated. The exhaust side A / F sensor 9 is shared with the A / F sensor in front of the injector. Further, the EGR A / F sensor 19 is shared for the A / F sensor after the injector.

  The electronic control unit 21 estimates the fuel injection amount of the injector based on the average value of the change amounts of the A / F sensor before and after the injector at the time of reforming (reforming ON) in the fuel reformer 16 (Calculating the estimated injection amount) (steps A3 and A4 in FIGS. 10A to 10C). Here, the electronic control unit 21 calculates the estimated injection amount of the injector based on the difference between the sensor values of the A / F sensor before and after the injector and the average value of the differences between the sensor values calculated in the above processing.

(Feedback control of fuel injection amount)
After calculating the estimated injection amount in the above process, the electronic control unit 21 corrects the fuel injection amount of the injector based on the calculated estimated injection amount and the target injection amount calculated separately (step in FIG. 10A) A5), end a series of processing. That is, the electronic control unit 21 uses the calculated estimated injection amount for feedback control of the fuel injection amount of the injector.

Thus, as a result of the electronic control unit 21 monitoring the sensor values of the A / F sensors before and after the injector, the value of A / F (air-fuel ratio) changes before and after fuel injection. The electronic control unit 21 estimates the fuel injection amount of the injector based on the change amount, and feeds it back to the fuel injection amount control of the injector, whereby a highly accurate and high response injection amount can be realized. This makes it possible to reduce the variation in the concentration of hydrogen (H ₂ ) generated by the reforming reaction.

(Control to determine the transition to the injector cleaning mode)
As another method, the electronic control unit 21 calculates the error amount between the target injection amount and the estimated injection amount after calculating the estimated injection amount in the above process (step B5 in FIG. 10B and FIG. 10C). The tolerance value stored is compared with this amount of error (FIG. 10B, step B6 in FIG. 10C).

At this time, when the error amount exceeds the allowable value (Yes in step B6 in FIG. 10B), the electronic control unit 21 determines that the injector is clogged in the depot and shifts to the injector cleaning mode (FIG. 10B). Step B7).
Furthermore, when the reforming by the fuel reformer 16 is not performed (reforming OFF) (No at step A3 in FIG. 10B), the electronic control unit 21 determines that the error amount is within the allowable value (FIG. 10B). 10B (No in step B6) or when the mode shifts to the injector cleaning mode (after step B7 in FIG. 10B), the series of processes is ended.

Alternatively, when the error amount exceeds the allowable value (Yes in step B6 of FIG. 10C), the electronic control unit 21 adds a timer value (or a counter value) for each unit time (for example, 1 for every one second) (Step C7 in FIG. 10C), the timer value is compared with the predetermined duration (step C8 in FIG. 10C), and when the timer value exceeds the predetermined duration (Yes in step C8 in FIG. 10C) It may be determined that a deposit clogged up has occurred, and the mode may shift to the injector cleaning mode (step C9 in FIG. 10C). Here, the predetermined duration is a predetermined value (predetermined value).
Furthermore, the electronic control unit 21 resets the timer value when the amount of error falls within the allowable value (No in step B6 of FIG. 10C) or when switching to the injector cleaning mode (after step C9 of FIG. 10C). (Step C10 in FIG. 10C), and the series of processing ends.

Here, the electronic control unit 21 continues the addition of the timer value (step C7 of FIG. 10C) until the timer value exceeds the predetermined duration (No in step C8 of FIG. 10C).
As another method, the electronic control unit 21 repeats the above-described series of processing while continuing addition of the timer value until the timer value exceeds the predetermined duration (No in step C8 of FIG. 10C) (FIG. 10C (return to step A1), when the reforming in the fuel reformer 16 is not performed (reforming OFF) while repeating the above series of processes (No in step A3 of FIG. 10C) Alternatively, when the error amount falls within the allowable value (No in step B6 of FIG. 10C), the timer value may be reset (step C10 of FIG. 10C), and the above series of processes may be ended.
In this case, when the timer value exceeds the predetermined duration (Yes in step C8 of FIG. 10C), the electronic control unit 21 determines that the injector is clogged while the above-described series of processing is repeated. And shift to the injector cleaning mode (step C9 in FIG. 10C). That is, the electronic control unit 21 determines the deterioration of the injector based on the temporal change of the estimated injection amount, and shifts to the injector cleaning mode.
At this time, since the addition of the timer value continues the processing being executed (the first step C7 in FIG. 10C), the addition of the new timer value is not started while repeating the above series of processing.

  As described above, the electronic control unit 21 compares the target injection amount and the injection amount estimated value, and starts the injector cleaning mode when the difference exceeds a predetermined threshold and the state continues for a predetermined time. . As a result, the injector cleaning mode can be minimized, and deterioration in fuel consumption and drivability can be avoided. Further, by utilizing the sensors mounted in the exhaust gas recirculation system including the internal combustion engine, it is possible to realize the fuel reformer according to the embodiment of the present invention at low cost.

  Further, the above-mentioned “feedback control of fuel injection amount” (see FIG. 10A) and “transition determination control to the injector cleaning mode” (see FIG. 10B or FIG. 10C) may be performed simultaneously and in parallel. For example, by correcting the fuel injection amount of the injector when or before shifting to the injector cleaning mode, it can be expected to more efficiently eliminate the deposit clogging.

  As described above, in the fuel reforming method according to one embodiment of the present invention, at least a portion of the fuel (gasoline) is reformed to hydrogen by the chemical reaction on the reforming catalyst, and the reforming including the hydrogen is performed With respect to the fuel reformer 16 for improving the thermal efficiency of the internal combustion engine 1 by mixing the gas with the intake air and burning it, the electronic control unit 21 detects the state quantities of the gas before and after the injector. The fuel injection amount of the injector is estimated (the estimated injection amount is calculated) based on the change in the state amount of gas before and after, and the fuel reformer 16 is calculated based on the estimated fuel injection amount (the estimated injection amount). The fuel injection amount to the fuel injection is corrected, and the deterioration of the injector is detected. The state quantities of the gas before and after the injector are any of the fuel concentration, the oxygen concentration, and the temperature. For example, an A / F sensor is used to detect oxygen concentration. The exhaust side A / F sensor 9 is shared with the A / F sensor in front of the injector. Further, the EGR A / F sensor 19 is shared for the A / F sensor after the injector.

  For example, when the electronic control unit 21 estimates the amount of fuel injection based on the change in the amount of state of gas before and after the injector, the fuel injection is performed based on the amount of change in the sensor value of the A / F sensor. Calculate or estimate the quantity. At this time, the fuel injection amount may be calculated or estimated using a value obtained by averaging the change amounts of the sensor values of the A / F sensor. Further, the amount of change in the sensor value of the A / F sensor may be calculated or estimated based on the amount of change after a predetermined period has elapsed since the end of the injection period.

  In addition, when the above fuel injection amount is estimated, the A / F sensor is corrected in a state where the fuel is not injected. At this time, if the estimated fuel injection amount is larger than the target injection amount, a correction to reduce the fuel injection amount is added. Conversely, if the estimated fuel injection amount is smaller than the target injection amount, a correction is made to increase the fuel injection amount.

  Also, when detecting the above-mentioned deterioration of the injector, the difference between the estimated fuel injection amount and the target injection amount is calculated, and this difference exceeds the fuel injection amount threshold value stored in advance in the electronic control unit. If so, it is determined that the injector has deteriorated. At this time, it is determined that the injector has deteriorated when the estimated fuel injection amount continues to be less than or equal to the threshold for a predetermined time stored in advance in the electronic control unit. A timer value is used for this continuation determination. At this time, when the difference between the estimated fuel injection amount and the target fuel amount is larger than the threshold of the fuel injection amount stored in advance in the electronic control device, the timer value is added per unit time. Conversely, if the difference between the estimated fuel injection amount and the target fuel amount is equal to or less than the fuel injection amount threshold value stored in advance in the electronic control unit, the timer value is reset.

(Effect of this embodiment)
According to the present embodiment, the following effects can be obtained.
(1) In the fuel reforming method according to the present embodiment, at least a portion of the fuel is reformed to hydrogen by a chemical reaction on the reforming catalyst in the fuel reformer, and the hydrogen-containing gas is used as the intake air. In order to improve the thermal efficiency of the internal combustion engine by mixing it with the internal combustion engine, the state quantities of the gas before and after the injector that injects the fuel to the reforming catalyst are detected, and the gas states before and after the injector The fuel injection amount of the injector is estimated based on the change of the amount, and the fuel injection amount of the injector is corrected based on the estimated fuel injection amount.
Thus, the fuel injection amount is estimated based on the change of the state quantity of gas before and after the injector, and the fuel injection amount to the fuel reformer is corrected based on the estimated fuel injection amount, The amount of reformed fuel can be corrected before fuel reforming.

(2) In the fuel reforming method according to the present embodiment, when the estimated fuel injection amount is larger than the target injection amount, a correction is made to reduce the fuel injection amount of the injector, and the estimated fuel injection amount is the target. If the injection amount is smaller than the injection amount, a correction is made to increase the fuel injection amount of the injector.
As a result, the amount of reformed fuel can be properly corrected.

(3) In the fuel reforming method according to the present embodiment, the difference between the estimated fuel injection amount and the target injection amount is calculated, and when the difference is larger than the threshold value, it is determined that the injector has deteriorated, and the injector is cleaned. Transition to mode
As described above, by determining the difference between the estimated fuel injection amount and the target injection amount, it is possible to determine that the injector has deteriorated and shift to the injector cleaning mode.

(4) In the fuel reforming method according to the present embodiment, when the difference is larger than the threshold value, the timer value is added per unit time, and it is determined that the injector has deteriorated when the timer value reaches a predetermined duration time. If the difference is less than or equal to the threshold value, the timer value is reset.
At this time, the process of estimating the fuel injection amount and calculating the difference between the estimated fuel injection amount and the target injection amount is repeated until the timer value reaches the predetermined duration, and the timer value reaches the predetermined duration during that time If the difference is lower than the threshold value before, the timer value may be reset without determining that the injector has deteriorated.
As described above, by minimizing the number of transitions of the injector cleaning mode to the minimum necessary number of transitions, deterioration of fuel efficiency and drivability due to excessive injector cleaning can be avoided.

(5) In the fuel reforming method according to the present embodiment, the fuel reformer is disposed in the flow path of the EGR gas, and uses a time integration value obtained by multiplying the EGR rate and the fuel injection amount of the injector by the sensitivity coefficient. The amount of adhesion of the depot attached to the injector is estimated. When the EGR rate> 0% and the fuel injection amount of the injector = 0, the estimated adhesion amount of the depot is increased. When the EGR rate> 0% and the fuel injection amount of the injector> 0, the estimated adhesion amount of the depot is decreased. At this time, the amount of increase in the estimated value of the adhesion amount of the depot is increased as the EGR rate is higher. As the fuel injection amount of the injector increases, the decrease amount of the estimated value of the deposition amount of the depot increases. As a result, the deposition amount of the depot can be properly estimated, and before the problems such as the deposition of the depot become apparent Since the mode can be switched to the cleaning mode, the influence on the drivability and fuel consumption can be suppressed.

(6) In the fuel reforming method according to the present embodiment, the injector is disposed such that the fuel is directed to the central axis of the reforming catalyst, and the distribution of the fuel concentration when the fuel reaches the reforming catalyst is reformed. The distribution near the central axis of the catalyst is higher in fuel concentration than in the periphery.
As a result, the fuel concentration can be increased near the central axis in accordance with the temperature increase near the central axis of the reforming catalyst due to the heat radiation from the catalyst container.

(7) In the fuel reforming method according to the present embodiment, the central axis of the injection port of the injector is added in consideration of the deviation of the central axis of the temperature distribution due to the partial flow caused by the bending of the pipe connected to the fuel reformer. Is offset from the central axis of the reforming catalyst.
As described above, when the gas flow is uneven depending on the piping layout, by laying out the spray center at the maximum value of the flow velocity distribution, the temperature near the central axis of the reforming catalyst is high due to the heat radiation from the catalyst container. The fuel concentration can be increased toward the central axis according to the

(8) In the fuel reforming method according to the present embodiment, the central axis of the catalyst container holding the reforming catalyst in the fuel reformer coincides with the pipe connected to the catalyst container. At this time, the cross sectional area of the catalyst container is made larger than the cross sectional area of the pipe.
Thus, if the cross-sectional area of the catalyst container is larger than the cross-sectional area of the pipe connected to the catalyst container, the range of the temperature distribution in the catalyst container becomes wider, and the heat dissipation from the catalyst container can be reduced.

(9) In the fuel reforming method according to the present embodiment, a stirrer is provided downstream of the injector, and the injection port of the injector is a spray port for injecting fuel in the form of mist, and the opening of the central portion of the spray port of the injector The area is made relatively larger than the opening area of the peripheral part.
As described above, by biasing the fuel distribution to the region where the catalyst temperature is high, the temperature distribution approaches the central axis of the catalyst container as viewed from the cross section of the reforming catalyst due to heat radiation from the catalyst container (case). It can be made higher as it gets farther from the central axis.

  While the invention has been described with reference to particular embodiments, it is not intended that the invention be limited by these descriptions. Various modifications of the disclosed embodiments, as well as alternative embodiments of the present invention, will be apparent to persons skilled in the art upon reference to the description of the invention. Therefore, it is to be understood that the claims cover these modifications or embodiments which fall within the scope and spirit of the present invention.

Reference Signs List 1 internal combustion engine 1a fuel injection device 1b in-cylinder pressure sensor 2 intake passage 3 air flow meter 4 throttle chamber 5 supercharger 6 intake side hydrogen sensor 7 fuel tank 8 exhaust passage 9 exhaust side A / F sensor 10 exhaust catalyst 11 exhaust side oxygen sensor 12 circulation passage 13 temperature sensor for EGR 14 fuel injection device for reforming (injector)
Reference Signs List 15 fuel evaporator 16 fuel reformer 16a temperature regulator 16b reforming temperature sensor 17 hydrogen sensor for EGR 18 EGR cooler 19 A / F sensor for EGR 20 EGR valve 21 electronic control unit

Claims (19)

At least a portion of the fuel is reformed to hydrogen by a chemical reaction on the reforming catalyst in the fuel reformer, and the hydrogen-containing gas is mixed with the intake air and combusted in the internal combustion engine by the internal combustion engine. Detecting the amount of state of gas before and after the fuel reformer injecting the fuel to the reforming catalyst when improving the thermal efficiency of the fuel cell ;
Estimating a fuel injection amount of the injector based on a change of a state quantity of gas before and after the fuel reformer ,
Correcting the fuel injection amount of the injector based on the estimated fuel injection amount ;
Calculating a difference between the estimated fuel injection amount and the target injection amount;
A fuel reforming method characterized in that when the difference is larger than a threshold, it is judged that the injector has deteriorated, and the mode is shifted to the cleaning mode of the injector . If the estimated fuel injection amount is larger than the target injection amount, a correction is made to reduce the fuel injection amount of the injector,
The fuel reforming method according to claim 1, wherein a correction for increasing the fuel injection amount of the injector is added when the estimated fuel injection amount is smaller than a target injection amount. When the difference is larger than the threshold value, a timer value is added per unit time, and when the timer value reaches a predetermined value, it is determined that the injector has deteriorated.
If the difference is below a threshold, the fuel reforming method according to claim 1 for resetting the timer value. The fuel reformer is disposed in the flow path of the EGR gas, and estimates the adhesion amount of the depot adhering to the injector based on the EGR rate and the fuel injection amount of the injector,
When the EGR rate> 0% and the fuel injection amount of the injector = 0, the estimated adhesion amount of the depot is increased,
When the EGR rate> 0% and the fuel injection amount of the injector> 0, the estimated value of the adhesion amount of the depot is decreased,
As the EGR rate is higher, the increase amount of the estimated value of the adhesion amount of the depot is increased;
The fuel reforming method according to any one of claims 1 to 3 , wherein the reduction amount of the estimated value of the adhesion amount of the depot is increased as the fuel injection amount of the injector is larger. The injector is disposed such that the fuel is directed to the central axis of the reforming catalyst, and the distribution of the fuel concentration when the fuel reaches the reforming catalyst is in the vicinity of the central axis of the reforming catalyst. The fuel reforming method according to any one of claims 1 to 4 , wherein the fuel concentration has a distribution higher than that of the fuel concentration. The central axis of the injection port of the injector is shifted from the central axis of the reforming catalyst, taking into consideration the deviation of the central axis of the temperature distribution due to the partial flow caused by the bending of the pipe connected to the fuel reformer The fuel reforming method according to any one of claims 1 to 4 . A central axis of a catalyst container for holding the reforming catalyst in the fuel reformer and a pipe connected to the catalyst container coincide with each other,
The fuel reforming method according to any one of claims 1 to 6 , wherein a cross sectional area of the catalyst container is made larger than a cross sectional area of the pipe. A stirrer is provided downstream of the injector, the injection port of the injector is a spray port for injecting the fuel in a mist, and the opening area of the central part of the spray port of the injector is relative to the opening area of the peripheral part The fuel reforming method according to any one of claims 1 to 7 , wherein the fuel reforming method is as large as possible. A fuel reformer that improves the thermal efficiency of an internal combustion engine by reforming at least a portion of fuel into hydrogen by a chemical reaction on a reforming catalyst and mixing the gas containing hydrogen with intake air for combustion. When,
An injector for injecting the fuel to the fuel reformer;
An air-fuel ratio sensor for detecting state quantities of gas before and after the fuel reformer ;
Based on the change in the state quantity of gas before and after the fuel reformer, to estimate the fuel injection amount of the injector, on the basis of the estimated fuel injection amount, of the injector to the fuel reformer An electronic control unit that corrects the fuel injection amount ;
The electronic control unit calculates a difference between the estimated fuel injection amount and the target injection amount, and determines that the injector has deteriorated if the difference is larger than a threshold, and shifts to the cleaning mode of the injector Fuel reformer characterized by having. At least a portion of the fuel is reformed to hydrogen by a chemical reaction on the reforming catalyst in the fuel reformer disposed in the EGR gas flow path, and the hydrogen-containing gas is mixed with the intake air to perform internal combustion When the thermal efficiency of the internal combustion engine is improved by combustion in the engine, state quantities of gas before and after the fuel reformer that injects the fuel to the reforming catalyst are detected.
Estimating a fuel injection amount of the injector based on a change of a state quantity of gas before and after the fuel reformer,
Correcting the fuel injection amount of the injector based on the estimated fuel injection amount;
The amount of adhesion of the depot adhering to the injector is estimated based on the EGR rate and the fuel injection amount of the injector,
When the EGR rate> 0% and the fuel injection amount of the injector = 0, the estimated adhesion amount of the depot is increased,
When the EGR rate> 0% and the fuel injection amount of the injector> 0, the estimated value of the adhesion amount of the depot is decreased,
As the EGR rate is higher, the increase amount of the estimated value of the adhesion amount of the depot is increased;
A fuel reforming method, wherein the amount of decrease of the estimated value of the deposition amount of the depot is increased as the fuel injection amount of the injector increases. At least a portion of the fuel is reformed to hydrogen by a chemical reaction on the reforming catalyst in the fuel reformer, and the hydrogen-containing gas is mixed with the intake air and combusted in the internal combustion engine by the internal combustion engine. Detecting the amount of state of gas before and after the fuel reformer injecting the fuel to the reforming catalyst when improving the thermal efficiency of the fuel cell;
Estimating a fuel injection amount of the injector based on a change of a state quantity of gas before and after the fuel reformer,
Correcting the fuel injection amount of the injector based on the estimated fuel injection amount;
The injector is disposed such that the fuel is directed to the central axis of the reforming catalyst, and the distribution of the fuel concentration when the fuel reaches the reforming catalyst is in the vicinity of the central axis of the reforming catalyst. A fuel reforming method characterized in that the distribution of fuel concentration is higher than that of the fuel reforming method. At least a portion of the fuel is reformed to hydrogen by a chemical reaction on the reforming catalyst in the fuel reformer, and the hydrogen-containing gas is mixed with the intake air and combusted in the internal combustion engine by the internal combustion engine. Detecting the amount of state of gas before and after the fuel reformer injecting the fuel to the reforming catalyst when improving the thermal efficiency of the fuel cell;
Estimating a fuel injection amount of the injector based on a change of a state quantity of gas before and after the fuel reformer,
Correcting the fuel injection amount of the injector based on the estimated fuel injection amount;
The central axis of the injection port of the injector is shifted from the central axis of the reforming catalyst, taking into consideration the deviation of the central axis of the temperature distribution due to the partial flow caused by the bending of the pipe connected to the fuel reformer Fuel reforming method characterized in that. At least a portion of the fuel is reformed to hydrogen by a chemical reaction on the reforming catalyst in the fuel reformer, and the hydrogen-containing gas is mixed with the intake air and combusted in the internal combustion engine by the internal combustion engine. Detecting the amount of state of gas before and after the fuel reformer injecting the fuel to the reforming catalyst when improving the thermal efficiency of the fuel cell;
Estimating a fuel injection amount of the injector based on a change of a state quantity of gas before and after the fuel reformer,
Correcting the fuel injection amount of the injector based on the estimated fuel injection amount;
A central axis of a catalyst container for holding the reforming catalyst in the fuel reformer and a pipe connected to the catalyst container coincide with each other,
A fuel reforming method, wherein a cross sectional area of the catalyst container is made larger than a cross sectional area of the pipe. At least a portion of the fuel is reformed to hydrogen by a chemical reaction on the reforming catalyst in the fuel reformer, and the hydrogen-containing gas is mixed with the intake air and combusted in the internal combustion engine by the internal combustion engine. Detecting the amount of state of gas before and after the fuel reformer injecting the fuel to the reforming catalyst when improving the thermal efficiency of the fuel cell;
Estimating a fuel injection amount of the injector based on a change of a state quantity of gas before and after the fuel reformer,
Correcting the fuel injection amount of the injector based on the estimated fuel injection amount;
A stirrer is provided downstream of the injector, and an injection port of the injector mists the fuel.
The fuel reforming method, wherein the opening area of the central portion of the injection port of the injector is made relatively larger than the opening area of the peripheral portion. A fuel reformer that improves the thermal efficiency of an internal combustion engine by reforming at least a portion of fuel into hydrogen by a chemical reaction on a reforming catalyst and mixing the gas containing hydrogen with intake air for combustion. When,
An injector for injecting the fuel to the fuel reformer;
An air-fuel ratio sensor for detecting state quantities of gas before and after the fuel reformer;
The fuel injection amount of the injector is estimated based on the change of the state quantity of gas before and after the fuel reformer, and the injector to the fuel reformer is estimated based on the estimated fuel injection amount. An electronic control unit that corrects the fuel injection amount;
The fuel reformer is disposed in the EGR gas flow path,
  The electronic control unit estimates the adhesion amount of the depot adhering to the injector based on the EGR rate and the fuel injection amount of the injector,
When the EGR rate> 0% and the fuel injection amount of the injector = 0, the estimated adhesion amount of the depot is increased,
When the EGR rate> 0% and the fuel injection amount of the injector> 0, the estimated value of the adhesion amount of the depot is decreased,
As the EGR rate is higher, the increase amount of the estimated value of the adhesion amount of the depot is increased;
A fuel reformer characterized in that the amount of decrease of the estimated value of the adhesion amount of the depot is increased as the fuel injection amount of the injector is larger. A fuel reformer that improves the thermal efficiency of an internal combustion engine by reforming at least a portion of fuel into hydrogen by a chemical reaction on a reforming catalyst and mixing the gas containing hydrogen with intake air for combustion. When,
An injector for injecting the fuel to the fuel reformer;
An air-fuel ratio sensor for detecting state quantities of gas before and after the fuel reformer;
The fuel injection amount of the injector is estimated based on the change of the state quantity of gas before and after the fuel reformer, and the injector to the fuel reformer is estimated based on the estimated fuel injection amount. An electronic control unit that corrects the fuel injection amount;
The injector is disposed such that the fuel is directed to the central axis of the reforming catalyst, and the distribution of the fuel concentration when the fuel reaches the reforming catalyst is in the vicinity of the central axis of the reforming catalyst. A fuel reformer characterized by having a distribution with a higher fuel concentration than that. A fuel reformer that improves the thermal efficiency of an internal combustion engine by reforming at least a portion of fuel into hydrogen by a chemical reaction on a reforming catalyst and mixing the gas containing hydrogen with intake air for combustion. When,
An injector for injecting the fuel to the fuel reformer;
An air-fuel ratio sensor for detecting state quantities of gas before and after the fuel reformer;
The fuel injection amount of the injector is estimated based on the change of the state quantity of gas before and after the fuel reformer, and the injector to the fuel reformer is estimated based on the estimated fuel injection amount. An electronic control unit that corrects the fuel injection amount;
The central axis of the injection port of the injector is shifted from the central axis of the reforming catalyst, taking into consideration the deviation of the central axis of the temperature distribution due to the partial flow caused by the bending of the pipe connected to the fuel reformer A fuel reformer characterized by A fuel reformer that improves the thermal efficiency of an internal combustion engine by reforming at least a portion of fuel into hydrogen by a chemical reaction on a reforming catalyst and mixing the gas containing hydrogen with intake air for combustion. When,
An injector for injecting the fuel to the fuel reformer;
An air-fuel ratio sensor for detecting state quantities of gas before and after the fuel reformer;
The fuel injection amount of the injector is estimated based on the change of the state quantity of gas before and after the fuel reformer, and the injector to the fuel reformer is estimated based on the estimated fuel injection amount. An electronic control unit that corrects the fuel injection amount;
A central axis of a catalyst container for holding the reforming catalyst in the fuel reformer and a pipe connected to the catalyst container coincide with each other,
A fuel reformer characterized in that a cross sectional area of the catalyst container is made larger than a cross sectional area of the pipe. A fuel reformer that improves the thermal efficiency of an internal combustion engine by reforming at least a portion of fuel into hydrogen by a chemical reaction on a reforming catalyst and mixing the gas containing hydrogen with intake air for combustion. When,
An injector for injecting the fuel to the fuel reformer;
An air-fuel ratio sensor for detecting state quantities of gas before and after the fuel reformer;
The fuel injection amount of the injector is estimated based on the change of the state quantity of gas before and after the fuel reformer, and the injector to the fuel reformer is estimated based on the estimated fuel injection amount. An electronic control unit that corrects the fuel injection amount;
A stirrer is provided downstream of the injector, the injection port of the injector is a spray port for injecting the fuel in a mist, and the opening area of the central part of the spray port of the injector is relative to the opening area of the peripheral part The fuel reformer characterized by making it large.

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