JP6034133B2 - Exhaust device for internal combustion engine - Google Patents

Description

  The present invention relates to an exhaust device for an internal combustion engine.

  Lead-free MMT (methylcyclopentadienyl manganese tricarbonyl) or the like is used as an additive for gasoline, which is a kind of fuel for internal combustion engines. Since MMT is an organic metal, it is regarded as a chemical substance related to environmental problems, and its use requires attention. MMT is burned in a combustion chamber of each cylinder of an internal combustion engine such as a gasoline engine to generate manganese oxide. Manganese oxide contained in the exhaust gas of the internal combustion engine is purified by a catalyst device provided downstream of the exhaust manifold of the internal combustion engine.

  However, manganese oxide in the exhaust gas may adhere to the catalyst of the catalyst device and cause clogging. If the catalyst is clogged, the exhaust gas flow is hindered, which may increase the back pressure of the internal combustion engine. When the back pressure of the internal combustion engine increases, excessive back pressure is applied to the upstream end face of the catalyst in the catalyst device. Therefore, if the back pressure becomes larger than the force that holds the catalyst, the catalyst may fall off downstream. is there. In addition, when the back pressure of the internal combustion engine increases, the resistance when closing the exhaust valve increases, the lash adjuster extends and the oil that becomes the damper is excessively sucked, and the exhaust valve becomes incompletely closed. Sometimes. Furthermore, when the back pressure of the internal combustion engine increases, the output of the internal combustion engine decreases, acceleration may worsen, and traveling performance may deteriorate.

  In order to suppress such clogging of the catalyst, an exhaust system for an internal combustion engine has been developed in which ignition is stopped during a combustion cycle in a predetermined cylinder and fuel is exploded in an exhaust pipe upstream of the catalyst. (For example, refer to Patent Document 1). According to the exhaust device of the internal combustion engine, the manganese oxide that has started to accumulate on the catalyst can be removed by the pressure wave generated by the explosion in the exhaust pipe on the upstream side of the catalyst. In addition, in this exhaust system of an internal combustion engine, if clogging of the catalyst cannot be removed even if the fuel is exploded in the exhaust pipe upstream of the catalyst, a warning lamp provided on the dashboard is turned on. Yes.

JP 2008-190501 A

  However, the conventional exhaust system for an internal combustion engine has a problem that the temperature of the catalyst rises due to the explosion in the exhaust pipe, and the catalyst deteriorates. In addition, since combustion ends before the removal of the manganese oxide, there is a problem that clogging is promoted by the remaining manganese oxide.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide an exhaust device for an internal combustion engine that can suppress clogging of the catalyst by manganese oxide more than before without degrading the catalyst. And

In order to achieve the above object, an exhaust system for an internal combustion engine according to the present invention is (1) an exhaust system for an internal combustion engine equipped with a catalyst for purifying exhaust gas, and a notification means for notifying a driver of predetermined information; Motoring means capable of motoring the internal combustion engine, and exhaust gas pressure measuring means capable of measuring the pressure of the exhaust gas, wherein the pressure of the exhaust gas measured by the exhaust gas pressure measuring means is a predetermined pressure. The notification means is operated on the condition that it is larger, and the internal combustion engine is motored by the motoring means for a predetermined time at a predetermined rotational speed, and the predetermined rotational speed is detected by the manganese oxidation deposited on the catalyst. A second excitation force that is greater than a first excitation force that is an excitation force that is large enough to screen off an object from the catalyst and that causes metal fatigue on the exhaust device. Configured to set the rotational speed to produce a force smaller excitation force.

  In general, catalyst clogging due to manganese oxide occurs through the following process. (1) The vehicle travels for a certain period of time using manganese-containing fuel as fuel. (2) Manganese oxide is deposited on the upstream end of the catalyst. (3) Manganese oxide adheres to the upstream end of the catalyst. (4) Repeat (2) and (3) above. (5) Catalyst clogging due to manganese oxide occurs.

  According to the configuration of the present invention, the exhaust device of the internal combustion engine determines that the catalyst clogging with the manganese oxide is larger than the predetermined amount when the pressure of the exhaust gas is larger than the predetermined pressure. When the exhaust device of the internal combustion engine determines that the catalyst is clogged with manganese oxide more than a predetermined amount, the exhaust device operates the notification means. Thereby, the driver | operator can recognize that the catalyst clogging with manganese oxide is more than predetermined amount.

  Further, when the exhaust device of the internal combustion engine determines that the catalyst clogging with the manganese oxide is larger than the predetermined amount, the internal combustion engine is motored by the motoring means for a predetermined time at a predetermined rotation speed. As a result, the internal combustion engine vibrates, and the vibration vibrates the exhaust device, giving an excitation force to the catalyst. Therefore, the exhaust device of the internal combustion engine gives an excitation force to the catalyst when the manganese oxide is deposited on the upstream end portion of the catalyst, so that the manganese oxide is deposited before the manganese oxide adheres to the catalyst. Shaking off from the catalyst can suppress clogging of the catalyst.

  In the exhaust system for an internal combustion engine according to (1) above, (2) a motoring switch for turning on and off the operation of the motoring means is provided, and after the notification means is operated, the motoring switch is turned on. On the condition that it is done, the internal combustion engine is motored by the motoring means for the predetermined time at the predetermined rotational speed.

  With this configuration, the driver recognizes that the catalyst clogging due to the manganese oxide is greater than a predetermined amount due to the operation of the notification means. The driver operates the motoring switch to turn on to eliminate the clogging of the catalyst, and the motoring means motors the internal combustion engine at a predetermined rotational speed for a predetermined time. As a result, according to the exhaust system of the internal combustion engine, the manganese oxide is shaken off from the catalyst by the motoring means according to the driver's intention. Therefore, the motoring means is automatically performed separately from the driver's intention. It is possible to prevent the driver from erroneously recognizing abnormal operation due to unexpected vibrations, as in the case of operating the vehicle. Further, according to the exhaust device of the internal combustion engine, the manganese oxide shake-off process from the catalyst by the motoring means can be performed with a minimum frequency, so that the fuel consumption can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the exhaust apparatus of the internal combustion engine which can suppress the clogging of the catalyst by manganese oxide than before can be provided, without deteriorating a catalyst.

1 is a schematic view showing an internal combustion engine equipped with an exhaust device for an internal combustion engine according to an embodiment of the present invention. It is a flowchart which shows operation | movement of the exhaust apparatus of the internal combustion engine which concerns on embodiment of this invention. It is a graph which shows the relationship between the engine speed in the exhaust apparatus of the internal combustion engine which concerns on embodiment of this invention, and the excitation force to a catalyst.

  Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the internal combustion engine to which the present invention is applied is applied to a gasoline vehicle using an in-line four-cylinder gasoline engine (hereinafter simply referred to as an engine) as the internal combustion engine.

  First, the configuration will be described.

  As shown in FIG. 1, the engine 1 of the present embodiment includes an engine body 2, an intake device 3, an exhaust device 4, a notification lamp 5 as a notification means, a motoring switch 6, an ECU (Electronic Control). Unit) 7. In the present embodiment, the exhaust device for the internal combustion engine includes an ECU 7 and controls a notification lamp 5 and a starter 17 described later.

  The engine body 2 includes a cylinder block 10 and a cylinder head 20. The cylinder block 10 and the cylinder head 20 include four cylinders 11. The cylinder 11 is provided with the vertical direction as the longitudinal direction.

  The cylinder block 10 includes a piston 12, a connecting rod 13, a crankshaft 14, and a crank angle sensor 15. The piston 12 is provided so as to reciprocate within the cylinder 11. The piston 12 is rotatably connected to the connecting rod 13. The connecting rod 13 is rotatably connected to the crankshaft 14. The crank angle sensor 15 detects the rotational speed of the crankshaft 14 and inputs it to the ECU 7.

  In the engine body 2, a combustion chamber 16 is formed by the cylinder block 10, the cylinder head 20, and the piston 12. The engine body 2 is configured to reciprocate the piston 12 by burning a mixture of fuel and air in the combustion chamber 16 at a desired timing, and to rotate the crankshaft 14 via the connecting rod 13.

  A starter 17 as motoring means is connected to the crankshaft 14 via a flywheel (not shown). The starter 17 is constituted by a DC motor, for example. The starter 17 can motor the engine 1. That is, when the starter 17 is driven, the crankshaft 14 is rotated via a flywheel or the like, and the engine 1 can be started.

  The cylinder head 20 includes an intake port 21, an intake valve 22, an intake camshaft (not shown), an exhaust port 23, an exhaust valve 24, an exhaust camshaft (not shown), and an ignition plug 25. The intake port 21 communicates the intake passage of the intake device 3 and the combustion chamber 16. The intake valve 22 opens and closes between the intake port 21 and the combustion chamber 16 by moving up and down, and controls the introduction of the intake air A from the intake passage of the intake device 3 to the combustion chamber 16. The intake camshaft moves the intake valve 22 up and down.

  The exhaust port 23 communicates the combustion chamber 16 and the exhaust passage of the exhaust device 4. The exhaust valve 24 opens and closes the combustion chamber 16 and the exhaust port 23 by raising and lowering, and controls the discharge of the exhaust gas G from the combustion chamber 16 to the exhaust passage of the exhaust device 4. The exhaust camshaft moves the exhaust valve 24 up and down.

  The intake valve 22 communicates the combustion chamber 16 with the intake passage when the valve is opened, and the exhaust valve 24 communicates the combustion chamber 16 with the exhaust passage when the valve is opened. When the piston 12 descends with the combustion chamber 16 communicating with the intake passage by opening the intake valve 22, the combustion chamber 16 can suck the intake air A through the intake passage. Further, when the piston 12 rises in a state where the combustion chamber 16 communicates with the exhaust passage by opening the exhaust valve 24, the combustion chamber 16 can exhaust the exhaust gas G through the exhaust passage.

  The spark plug 25 is provided in the combustion chamber 16 so as to be capable of spark ignition. The ignition plug 25 is configured so that the ignition timing is controlled by the ECU 7.

  The intake device 3 includes an intake port pipe 30, an air cleaner 31, an intake pipe 32, an air flow meter 33, a throttle valve 34, a surge tank 35, and an intake manifold 36. The air cleaner 31 is cleaned by removing dust and the like from the intake air A by a built-in filter at an upstream portion of the intake device 3. The air flow meter 33 detects the intake flow rate of the intake air A and inputs it to the ECU 7.

  The throttle valve 34 is provided between the air cleaner 31 and the surge tank 35 and adjusts the intake flow rate of the intake air A supplied to each cylinder 11 by electronic control. The intake manifold 36 connects the intake pipe 32 and each cylinder 11.

  The intake air A is distributed from the intake pipe 30 in the order of air cleaner 31 → throttle valve 34 → surge tank 35 → intake manifold 36 and flows into each cylinder 11. Further, the engine body 2 and the intake device 3 are connected by the connection between the intake manifold 36 and each cylinder 11.

  The exhaust device 4 includes an exhaust manifold 40, an exhaust pipe 41, a back pressure sensor 42 as a back pressure measuring means, an exhaust after-treatment device 43, and a tail pipe 44.

  The exhaust manifold 40 circulates the exhaust gas G discharged from each cylinder 11. By connecting the exhaust manifold 40 and each cylinder 11, the engine body 2 and the exhaust device 4 are connected. The exhaust pipe 41 connects the exhaust manifold 40 and the exhaust after-treatment device 43. The back pressure sensor 42 can measure the pressure of the exhaust gas G in the exhaust pipe 41 and inputs the measured gas pressure to the ECU 7.

  The exhaust after-treatment device 43 includes an oxidation catalytic converter (CCo) 46 and a diesel particulate filter (DPF) 47. The configuration of the exhaust after-treatment device 43 is not particularly limited, and a known or new one can be used.

In the present embodiment, the oxidation catalytic converter 46 includes a cylindrical casing 46a and a catalyst carrier 46b as a catalyst built in the casing 46a. As the catalyst substance contained in the catalyst carrier 46b, for example, Pt / CeO ₂ , Mn / CeO ₂ , Fe / CeO ₂ , Ni / CeO ₂ , Cu / CeO ₂ or the like can be used. The oxidation catalytic converter 46 is configured to react unburned components such as HC and CO contained in the exhaust gas G with O ₂ and oxidize them to CO, CO ₂ , H ₂ O and the like to purify them. The diesel particulate filter 47 collects PM (particulate matter). Therefore, the exhaust device 4 includes a catalyst that purifies the exhaust gas G.

  The tail pipe 44 is connected to the downstream side of the exhaust after-treatment device 43. The downstream end of the tail pipe 44 is open to the atmosphere. For this reason, the exhaust gas G that has passed through the exhaust after-treatment device 43 is discharged to the atmosphere via the tail pipe 44.

  The notification lamp 5 notifies the driver of predetermined information, and is provided, for example, on the dashboard of the vehicle. The notification lamp 5 is connected to the ECU 7 and can be blinked according to an instruction from the ECU 7. The motoring switch 6 is provided, for example, on a vehicle console. The motoring switch 6 is connected to the ECU 7 and switches on / off the operation of the starter 17 by an on / off operation.

  The ECU 7 is rewritable with a central processing unit (CPU) as a central processing unit, a ROM (Read Only Memory) for storing fixed data, and a RAM (Random Access Memory) for temporarily storing data A backup memory composed of a non-volatile memory, an input interface circuit having an A / D converter, a buffer, and the like, and an output interface circuit having a drive circuit and the like are included.

  For example, the ROM stores a manganese oxide removal program, a map, and the like according to the present embodiment, and functions as a storage device. The CPU executes arithmetic processing based on the manganese oxide removal program and map stored in the ROM. In the present embodiment, the vehicle control program is executed at predetermined time intervals (for example, 10 ms) by the ECU 7.

  In addition, a manganese-containing flag that stores whether or not manganese is contained in the fuel of the engine 1 according to the present embodiment is set in the RAM. For example, if the driver determines that manganese is attached to the exhaust passage of the exhaust device 4 using a manganese checker, the manganese-containing flag is set to ON by operating the setting switch of the vehicle. Yes. Alternatively, when the CPU determines that the vehicle is traveling in an area where manganese-containing fuel is used based on GPS information or the like, the manganese-containing flag is automatically set to ON.

  The motoring switch 6, the air flow meter 33, the back pressure sensor 42, and the like are connected to the input interface circuit of the ECU 7. Information detected by the motoring switch 6, the air flow meter 33, the back pressure sensor 42, and the like is taken into the ECU 7.

  A notification lamp 5 and a throttle motor (not shown) of the throttle valve 35 are connected to the output interface circuit of the ECU 7. Then, the ECU 7 controls the blinking of the notification lamp 5 or executes the operation control of the engine 1, for example, the opening degree control of the throttle valve 35 or the like.

  The exhaust system for an internal combustion engine according to the present embodiment includes a notification lamp 5, a starter 17, and a back pressure sensor 42. The exhaust gas G measured by the back pressure sensor 42 is greater than a predetermined pressure. As a condition, the notification lamp 5 is operated, and the engine 1 is motored by the starter 17 for a predetermined time at a predetermined rotational speed. Here, the predetermined pressure, the predetermined rotation speed, and the predetermined time can be appropriately set for each engine 1.

  Further, the exhaust system for an internal combustion engine of the present embodiment includes a motoring switch 6 and is operated at a predetermined rotational speed on condition that the motoring switch 6 is turned on after the notification lamp 5 is operated. During the time, the engine 1 is motored by the starter 17.

  In the exhaust system for the internal combustion engine of the present embodiment, the predetermined rotational speed is such that the excitation force of the catalyst carrier 46b is greater than a predetermined value due to vibration of the engine 1.

  Next, the operation will be described.

  Here, the operation of the exhaust device of the internal combustion engine in the present embodiment will be described with reference to the flowchart shown in FIG. This flowchart represents the execution content of the manganese removal program executed by the CPU of the ECU 7 using the RAM as a work area. Further, the vehicle may be running or stopped.

  Prior to execution of the manganese removal program, if the driver or the CPU determines that the vehicle is using manganese-containing fuel, the manganese-containing flag is turned on. Then, the ECU 7 determines whether or not the manganese-containing flag is on (step S1). If the ECU 7 determines that the manganese-containing flag is not on (step S1; NO), the process is returned to the main routine. Thereby, when the manganese-containing fuel is not used, it is not necessary to execute the following manganese removal program, so that the processing can be simplified.

  When the ECU 7 determines that the manganese-containing flag is on (step S1; YES), the ECU 7 detects whether or not manganese oxide is deposited on the catalyst carrier 46b (step S2). Whether or not manganese oxide is deposited on the catalyst carrier 46b is determined by the ECU 7 based on whether or not the pressure of the exhaust gas G detected by the back pressure sensor 42 is higher than a predetermined pressure. When the ECU 7 determines that no manganese oxide is deposited on the catalyst carrier 46b (step S2; NO), the process is returned to the main routine.

  When the ECU 7 determines that manganese oxide is deposited on the catalyst carrier 46b (step S2; YES), the ECU 7 turns on the notification lamp 5 (step S3). As a result, the driver recognizes that manganese oxide is deposited on the catalyst carrier 46b. When the driver determines that the manganese oxide should be removed from the catalyst support 46b, the motoring switch 6 is turned on.

  Then, the ECU 7 determines whether or not the motoring switch 6 is on (step S4). When the ECU 7 determines that the motoring switch 6 is on (step S4; YES), the ECU 7 operates the starter 17 to motor the engine 1 (step S5).

  Due to the motoring, the engine 1 vibrates, the exhaust device 4 resonates, and an excitation force is generated in the catalyst carrier 46b. The excitation force is determined by the mass of the catalyst carrier 46b and the acceleration to be shaken. The acceleration here is determined by the amplitude and frequency. Therefore, elements that determine the excitation force include all of mass, amplitude, and frequency. Further, the greater the mass, the greater the amplitude, and the higher the frequency, the greater the excitation force. The relationship between the engine speed Ne and the excitation force at this time is as shown in FIG. 3, for example. The relationship between the engine speed Ne and the excitation force shown here is an example, and this relationship varies depending on the engine specifications.

Here, the manganese oxide can be shaken off from the catalyst support 46b by applying an excitation force of a predetermined value or more. For example, as shown in FIG. 3, it sets the manganese oxide exciting force large enough to drop blow the catalyst carrier 46b to F _1. In this case, the engine rotation speed Ne during motoring needs to be set so that the excitation force is greater than F _1.

On the other hand, if the excitation force is too large, there is a possibility that the exhaust manifold 40 may be subjected to metal fatigue, which is not preferable. For example, it sets the excitation force magnitude would give metal fatigue in the exhaust manifold 40 to the F _2. In this case, the engine rotation speed Ne during motoring needs to be set so that the excitation force is smaller than F _2.

Therefore, in the case shown in FIG. 3, a preferred engine rotational speed Ne to drop wiped manganese oxide from the catalyst carrier 46b is a rotational speed N ₁ of the excitation force is smaller than the larger F ₂ than F _1. Accordingly, ECU 7 is an engine speed Ne and the _{N 1,} to perform motoring of the predetermined time. Further, the predetermined time here can be set as appropriate, and for example, several seconds of motoring can be set to a frequency of about several times for 10,000 kilometers traveling.

  After the end of motoring, or when the ECU 7 determines that the motoring switch 6 is not on (step S4; NO), the process is returned to the main routine.

  As described above, according to the exhaust device for an internal combustion engine according to the present embodiment, the ECU 7 determines that the catalyst clogging with manganese oxide is larger than the predetermined amount when the pressure of the exhaust gas G is larger than the predetermined pressure. To do. When the ECU 7 determines that the catalyst clogging due to the manganese oxide is greater than the predetermined amount, the ECU 7 turns on the notification lamp 5. Thereby, the driver | operator can recognize that the catalyst clogging with manganese oxide is more than predetermined amount.

  When the ECU 7 determines that the catalyst clogging due to the manganese oxide is greater than a predetermined amount, the ECU 7 motorizes the engine 1 by the starter 17 for a predetermined time at a predetermined rotation speed. As a result, the engine 1 vibrates, and the vibration vibrates the exhaust device 4 to apply an excitation force to the catalyst carrier 46b. Accordingly, the ECU 7 applies an excitation force to the catalyst carrier 46b when the manganese oxide is deposited on the upstream end of the catalyst carrier 46b, so that the manganese oxide is oxidized before the manganese oxide is fixed to the catalyst carrier 46b. The catalyst clogging can be suppressed by shaking off the material from the catalyst carrier 46b.

  Further, according to the exhaust device for an internal combustion engine according to the present embodiment, the driver recognizes that the catalyst clogging due to the manganese oxide is larger than the predetermined amount by the operation of the notification lamp 5. The driver operates the motoring switch 6 to turn on the catalyst 1 to eliminate the catalyst clogging, and the starter 17 motors the engine 1 for a predetermined time at a predetermined rotation speed. As a result, the ECU 7 executes the process of removing the manganese oxide from the catalyst by the starter 17 with the driver's intention, so that the starter 17 is automatically operated separately from the driver's intention. It is possible to prevent a person from erroneously recognizing abnormal operation due to unexpected vibration. Further, since the ECU 7 can perform the manganese oxide swing-off process from the catalyst carrier 46b by the starter 17 with a minimum frequency, the fuel efficiency can be improved.

  Further, according to the exhaust system for an internal combustion engine according to the present embodiment, the predetermined rotational speed of the motoring is such that the excitation force of the catalyst carrier 46b becomes larger than a predetermined value due to the vibration of the engine 1. For this reason, the ECU 7 rotates the starter 17 at a predetermined number of revolutions so that the excitation force generated in the catalyst carrier 46b can be larger than a predetermined value. Processing can be performed reliably.

  In the exhaust system for an internal combustion engine of the present embodiment described above, a case where the driver or the CPU determines whether or not the vehicle uses manganese-containing fuel prior to execution of the manganese removal program in the ECU 7 will be described. ing. However, the exhaust device for an internal combustion engine according to the present invention is not limited to this, and the ECU 7 may execute a manganese removal program for all fuels.

  Further, in the exhaust system for an internal combustion engine of the present embodiment described above, the case where the notification lamp 5 is used as the notification means has been described. However, the exhaust device for an internal combustion engine according to the present invention is not limited to this, and may be a notification buzzer or the like, for example.

  Further, in the exhaust system for an internal combustion engine of the present embodiment described above, when it is determined that manganese oxide is deposited on the catalyst carrier 46b, the notification lamp 5 is turned on to remove manganese oxide. A case where the driver determines whether or not is described. However, the exhaust device for an internal combustion engine according to the present invention is not limited to this, and for example, when it is determined that manganese oxide is deposited on the catalyst carrier 46b, all the manganese oxide may be removed. . In this case, the notification lamp 5 and the motoring switch 6 can be eliminated.

  Further, in the exhaust system for an internal combustion engine of the present embodiment described above, a case where the vehicle is a gasoline vehicle has been described. However, the exhaust device for an internal combustion engine according to the present invention is not limited to this, and may be a hybrid vehicle including, for example, a vehicle as a drive source and both an engine and a drive motor. In this case, the motoring of the engine 1 is not the starter 17 but uses, for example, a generator motor.

  As described above, the exhaust device for an internal combustion engine according to the present invention has an effect that the clogging of the catalyst by the manganese oxide can be suppressed more than before without deteriorating the catalyst. Useful for.

1 engine (internal combustion engine)
2 Engine body 3 Intake device 4 Exhaust device 5 Notification lamp (notification means)
6 Motoring switch 7 ECU
17 Starter (Motoring means)
42 Back pressure sensor (Back pressure measuring means)
46b Catalyst carrier (catalyst)
G exhaust gas

Claims (2)

An exhaust system for an internal combustion engine including a catalyst for purifying exhaust gas,
Informing means for notifying the driver of predetermined information, motoring means capable of motoring the internal combustion engine, and back pressure measuring means capable of measuring the pressure of the exhaust gas,
The notifying means is operated on the condition that the pressure of the exhaust gas measured by the back pressure measuring means is larger than a predetermined pressure, and the internal combustion engine is controlled by the motoring means for a predetermined time at a predetermined rotation speed. Motoring and
The predetermined rotational speed is greater than a first excitation force that is an excitation force large enough to screen the manganese oxide deposited on the catalyst from the catalyst, and the exhaust device is subjected to metal fatigue. An exhaust system for an internal combustion engine, characterized in that the engine speed is set to a rotational speed that generates an excitation force smaller than a second excitation force that is an excitation force to be applied. A motoring switch for turning on and off the operation of the motoring means;
The internal combustion engine is motored by the motoring means for the predetermined time at the predetermined rotational speed on the condition that the motoring switch is turned on after the notification means is activated. An exhaust system for an internal combustion engine according to claim 1.

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