JP4077641B2 - Heating method and heating apparatus in canister - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heating method and a heating apparatus in a canister that adsorbs and collects evaporated fuel evaporated from a fuel tank or the like mounted on a vehicle.
[0002]
[Prior art]
Conventionally, a canister that absorbs and collects evaporated fuel that evaporates from a fuel tank mounted on a vehicle while the engine is stopped, and purges (also referred to as desorption) to the intake pipe when the engine is started. A canister that heats the activated carbon to promote desorption of the evaporated fuel adsorbed on the activated carbon is known.
[0003]
However, since the activated carbon has a characteristic that the higher the temperature, the more the amount of evaporated fuel adsorbed on the activated carbon is desorbed. There is a problem that the evaporated fuel in the canister is purged in a large amount and the A / F feedback controllability is deteriorated.
[0004]
Therefore, conventionally, a single heater is built in the canister, and the heater is heated for a predetermined time from the start of the engine (at the start of purging) to enrich the air-fuel mixture at the start of the engine (at the start of purging). A device for preventing this is disclosed in, for example, Japanese Patent Laid-Open No. 63-150459.
[0005]
Also, a canister with a plurality of heaters incorporated in the activated carbon layer is disclosed in, for example, Japanese Utility Model Publication No. 57-75154.
[0006]
[Problems to be solved by the invention]
In any of the conventional techniques, all the heaters in the canister are turned off at the same time, so the evaporated fuel desorbed at the activated carbon part on the air port side at the end of the purge is re-adsorbed on the activated carbon on the tank port (purge port) side. However, there is a problem of accelerating deterioration of the activated carbon on the tank port side.
[0007]
Accordingly, the present invention provides a plurality of heaters and controls the order of on and off operations of these heaters to shorten the purge completion time and reduce the power consumption. It is an object of the present invention to provide a heating method and a heating device in a canister that can suppress deterioration of activated carbon due to adsorption.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a first invention according to claim 1 is a canister in which a tank port and a purge port are provided on one end side of the activated carbon layer, and an atmospheric port is provided on the other end side. A plurality of heaters are arranged from one end side to the other end side of the activated carbon layer, and the turn-on operation order of each heater is changed from the heater on one end side of the activated carbon layer to the heater on the other end side. The heating method in the canister is characterized in that the ON operation is sequentially performed and the OFF operation sequence is sequentially performed from the heater on the other end side toward the heater on the one end side .
[0009]
In the present invention, at the time of purging, each activated heater is individually turned on and off in a predetermined order to partially heat the activated carbon layer in an order suitable for purging or to stop the heating. Can do.
[0013]
Further, since the order of the off operation of the respective heaters so as to sequentially turn off operated toward the other end of the heater to the one end side of the heater with the air port, at the time of the purge completion, the heated end side Re-adsorption of the evaporated fuel purged from the activated carbon to the activated carbon on one end side is suppressed.
[0014]
The second invention according to claim 2, the tank port and the purge port provided on one end side of the activated carbon layer, in the canister provided with the air port at the other end, in the active carbon layer, from one side of the activated carbon layer A plurality of heaters are arranged toward the other end side, an intermediate heater is arranged between the heater on one end side of the activated carbon layer and the heater on the other end side, and the heater on the other end side is used as the intermediate heater. The heating method in the canister is such that the ON operation is prioritized and the OFF operation sequence is sequentially turned off from the heater on the other end side toward the heater on the one end side.
[0015]
In the present invention, it is possible to lengthen the heating time of the activated carbon on the atmospheric port side at the time of purging so that the remaining amount of evaporated fuel in the activated carbon can be almost eliminated. It is possible to reduce the amount released and to reduce the amount of evaporated fuel blown into the atmosphere when evaporated fuel is introduced during gasoline refueling.
[0016]
A third invention of claim 3, wherein, in the first or second aspect of the invention, the timing of the on-operation and off-operation of the respective heaters, and a preset value and the rate of temperature change of the activated carbon with respect to time This is a heating method in a canister that is determined by comparing the above.
[0017]
A fourth invention of claim 4, wherein, in the first or second aspect of the invention, said time of ON operation and OFF operation of the heaters, a heating method in a canister which is adapted to set the timer.
[0018]
By controlling the on-operation timing and the off-operation timing of each heater as in the third or fourth invention, the control becomes easy.
[0019]
A fifth invention of the fifth aspect, a tank port and a purge port provided on one end side of the activated carbon layer, in the canister provided with the air port at the other end, in the active carbon layer, from one side of the activated carbon layer A plurality of heaters arranged toward the other end side, a plurality of temperature sensors for detecting the temperature of the activated carbon in the vicinity of each heater, and an on operation timing and an off operation of each heater based on the detected temperature of each temperature sensor A heating device in a canister, characterized by having a control circuit for individually controlling timing.
[0020]
According to the present invention, the heating methods of the first to third inventions can be achieved.
[0021]
Sixth invention described in claim 6, a tank port and a purge port provided on one end side of the activated carbon layer, in the canister provided with the air port at the other end, in the active carbon layer, from one side of the activated carbon layer a plurality of heater disposed toward the other end, a heating apparatus in a canister and having a timer for controlling the plurality several each on actuation timing and the off-operation time of the heater independently.
[0022]
According to the present invention, the heating method of the fourth invention can be achieved.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described based on the examples shown in the drawings.
[0024]
1 and 2 show a first embodiment.
[0025]
FIG. 1 is a schematic view of a canister showing the arrangement of a heater and a temperature sensor as heating means in the present invention.
[0026]
In FIG. 1, the inside of the case 2 forming the canister 1 is partitioned into a first chamber 4 and a second chamber 5 by a partition wall 3. A first activated carbon layer 6 filled with activated carbon is formed in the first chamber 4, and a second activated carbon layer 7 filled with activated carbon is formed in the second chamber 5.
[0027]
A tank port 9 and a purge port 10 are provided on one side of the first activated carbon layer 6 through a chamber 8, and the tank port 9 communicates with a fuel tank (not shown) so that the evaporated fuel in the fuel tank is stored in the tank port. 9 is introduced into the canister 1. The purge port 10 communicates with an intake pipe of an engine (not shown).
[0028]
An air port 12 is provided on one side of the second activated carbon layer 7 through a chamber 11, and air is introduced into the canister 1 from the air port 12.
[0029]
The other sides of the first activated carbon layer 6 and the second activated carbon layer 7 communicate with each other through a chamber 13.
[0030]
The activated carbon layers 6 and 7 are formed in a U-shape in series. From the whole activated carbon layer, the tank port 9 and the purge port 10 are arranged on one end side of the activated carbon layer, and the atmosphere is on the other end side. Port 12 is arranged.
[0031]
In the activated carbon layers 6 and 7, a plurality of heaters are arranged. In the embodiment shown in the figure, two heaters A and B are provided in the first activated carbon 6 and two heaters A and B are provided in the second activated carbon layer 7. Heaters C and D are disposed. In addition, these heaters A to D are PTC heaters in this embodiment, and are arranged in series in a U shape along the flow of evaporated fuel and air in the canister 1, and the heater A is an activated carbon layer. Is disposed on one end side on the tank port 9 (purge port 10) side, heater D is disposed on the other end side of the activated carbon layer on the atmosphere port 12 side, and intermediate heaters B and C are disposed therebetween. ing. Among these heaters, the heater closest to the tank port 9 (purge port 10) is the first heater A, and the heaters sequentially arranged from the first heater A to the atmosphere port 12 are the second heater B, The third heater C and the fourth heater D are assumed.
[0032]
Each of the heaters A to D is controlled to be turned on and off at a predetermined timing, which will be described later, by a signal from a driving device 15 having a control circuit (CPU) 14.
[0033]
In the activated carbon layers 6 and 7, a plurality of temperature sensors E to H such as thermocouples for detecting the temperature of the activated carbon in the vicinity of the heaters A to D are arranged. It is arranged upstream of each heater in the flow direction of the evaporated fuel from the port 10) to the atmospheric port 12. The signals from these temperature sensors E to H are input to the control circuit 14, the first temperature sensor E controls the on / off operation of the first heater A, and the second temperature sensor F controls the second. The on / off operation of the heater B is controlled, the on / off operation of the third heater C is controlled by the third temperature sensor G, and the on / off operation of the fourth heater D is controlled by the fourth temperature sensor H. To be controlled.
[0034]
Next, the operation will be described.
[0035]
While the engine is stopped, the heaters A to D are in an off state, and the evaporated fuel introduced from the tank port 9 is from the tank port 9 side portion of the first activated carbon layer 6 to the atmosphere port 12 side of the second activated carbon layer 7. It is adsorbed and collected in sequence. Therefore, a larger amount of evaporated fuel is adsorbed and collected on the activated carbon on the tank port 9 side than on the other parts.
[0036]
Next, when the engine is started, the intake pipe negative pressure acts on the purge port 10, air is introduced from the atmospheric port 12, and the evaporated fuel adsorbed on the activated carbon of the activated carbon layers 6 and 7 is detached from the activated carbon. Then, it is purged from the purge port 10 together with air.
[0037]
The heating operation timing of each of the heaters A to D at the time of the purge starts from the first heater A, and then sequentially starts heating with the second heater B, the third heater C, and the fourth heater D. The heating operation is performed with a delay until the time. The on-operation timing of each of the heaters A to D will be described with reference to FIG.
[0038]
First, as shown in FIG. 2 (b), at the time T1 when the temperature decrease rate of the activated carbon of the first temperature sensor E section reaches a predetermined value from the purge start time T0, as shown in FIG. 2 (a). 1 heater A is turned on. The reason why the time T1 is determined from the temperature decrease rate of the activated carbon is that the activated carbon temperature during purging depends on the outside air temperature, the adsorbed state of the evaporated fuel, etc., and cannot be turned on at a specific temperature. Therefore, focusing on the fact that the activated carbon temperature decreases due to the latent heat of vaporization of the evaporated fuel as the purge starts, the temperature decrease rate is calculated by the CPU, and the on-operation is performed when this decrease rate is below the set value. Is. That is, as shown in FIG. 2 (b), the temperature decrease curve of the activated carbon from the start time T0 of the purge becomes gentle with the passage of time (the broken line indicates the temperature assuming no heating). The measured temperature (which is output as a voltage in this embodiment) is sampled by the CPU 14 at a constant sampling interval, and the temperature change amount for each sampling is set to a preset lowering rate setting value (hereinafter referred to as a first rate). The first heater A is turned on when the temperature becomes the following.
[0039]
Next, since the activated carbon of the second temperature sensor F section also has the same temperature decrease curve as described above, the temperature measured by the second temperature sensor F is sampled at a constant sampling interval by the CPU 14, The second heater B is turned on when the amount of temperature change for each sampling is equal to or less than a second set value that is smaller than the first set value in the case of the first temperature sensor E. As a result, the second heater B is turned on at time T2 which is later than the time T1 when the first heater A is turned on.
[0040]
Next, the third temperature sensor G part and the fourth temperature sensor H part will be described.
[0041]
As shown in FIGS. 2D and 2E, the temperature of the activated carbons of these temperature sensors G and H is lowered by the latent heat of vaporization when the purge is started, and it is considered that the evaporative fuel has been desorbed, and T3 and T4. The minimum temperature is reached. Then, since there is no vaporization latent heat of the evaporated fuel, the temperature of the activated carbon is raised so as to approach the ambient temperature. The temperature rise curve at this time becomes gentle with the passage of time as shown in FIGS. Further, the lowest temperature point T4 in the fourth temperature sensor H part is earlier than the lowest temperature point T3 in the third temperature sensor G part, and the temperature curve after the point T4 is higher than the temperature curve after the point T3. Be gentle.
[0042]
Therefore, similarly to the above, the temperature measured by the third temperature sensor G is sampled by the CPU 14 at a constant sampling interval, and a temperature change amount for each sampling is set in advance as an increase rate setting value (hereinafter referred to as a first rate change value). 3), the third heater C is turned on. Accordingly, the third heater C can be heated and operated at a time T5 that is later than the on-operation time T2 of the second heater B.
[0043]
Next, similarly, the temperature measured by the fourth temperature sensor H is sampled by the CPU 14 at a constant sampling interval, and the temperature change amount for each sampling is the third temperature sensor G in the case of the third temperature sensor G. The fourth heater D is turned on when it becomes equal to or larger than a fourth set value smaller than the set value. As a result, the fourth heater D can be heated and operated at a time T6 that is later than the on-operation time T5 of the third heater C.
[0044]
As described above, the heaters A to D are sequentially turned on after a predetermined time as shown in FIG.
[0045]
As described above, since the ON operation is performed sequentially from the first heater A on the tank port 9 (purge port 10) side to the fourth heater D on the atmospheric port side, the amount of evaporated fuel adsorbed is reduced. The activated carbon on the tank port 9 (purge port 10) side, which requires a large amount of purge air for completion of the purge and takes a long time to complete the purge, is first heated, and the purge completion time can be shortened.
[0046]
Further, since all the activated carbons are not heated at the same time, it is possible to prevent a large amount of evaporated fuel from being purged at the start of the purge, thereby preventing over-concentration of the air-fuel mixture at the start of the purge (when the engine is started). Does not deteriorate feedback controllability.
[0047]
Next, the timing for turning off the heaters A to D will be described.
[0048]
After all the heaters A to D are turned on, and after a predetermined time has elapsed, the fourth heater D on the atmosphere side is first turned off, and then the third heater C, The second heater B and the first heater A are sequentially turned off at a time interval toward the heater on the tank port 9 (purge port 10) side.
[0049]
The off operation timing of the heaters D to A will be described with reference to FIG.
[0050]
As described above, the temperature of the activated carbon in the vicinity after the time point T6 when the fourth heater D is turned on, that is, the temperature rise curve of the fourth temperature sensor H part is rapidly completed as shown in FIG. After getting up, the heater reaches the Curie point and becomes a gentle curve. Therefore, as in the case of the on-operation described above, the temperature measured by the fourth temperature sensor H (outputted as a voltage in this embodiment) is sampled by the CPU 14 at a constant sampling interval, and the temperature for each sampling. The fourth heater D is turned off at time T7 when the amount of change becomes equal to or less than a preset increase rate setting value (hereinafter abbreviated as the fifth setting value).
[0051]
Next, the temperature curves of the activated carbon in the vicinity after the time points T5, T2, and T1 when the third heater C, the second heater B, and the first heater A are turned on are also shown in FIGS. E) Since it becomes gentle as time elapses, time T8 when the rate of temperature increase becomes a value equal to or less than the sixth to eighth set values set in the same manner as the fourth heater D. , T9 and T10 are turned off.
[0052]
As a result, as shown in FIG. 2 (a), the fourth heater D on the air side is sequentially turned off from the fourth heater D toward the first heater A on the tank port 9 (purge port 10) side.
[0053]
Due to the off operation as described above, each heater is sequentially turned off after the heating time necessary for purging at that portion, so that it is possible to reduce power consumption (power saving).
[0054]
Further, since the heating is sequentially stopped from the activated carbon on the upstream side (atmosphere port 12 side) of the purge air flow, the high boiling point evaporated fuel purged with the activated carbon on the upstream side is downstream (tank port) at the purge end timing. (9 side) can be prevented from being re-adsorbed on the activated carbon, and the deterioration of the activated carbon, particularly the activated carbon on the tank port 9 (purge port 10) side can be prevented.
[0055]
3 and 4 show a second embodiment.
[0056]
In the second embodiment, the heater on the atmosphere side in the first embodiment, that is, the fourth heater D is arranged in a portion where the activated carbon in the activated carbon layer near the atmosphere introduction portion can be sufficiently heated. D ′ and a temperature sensor H ′ is arranged in the vicinity of the fourth heater D ′ so that the fourth heater D ′ is turned on in preference to the on-operation sequence of the first embodiment. It is what. That is, the on-operation is preferentially performed earlier than the intermediate second heater B and the third heater C. For example, as shown in FIG. 4 (e), the fourth heater D 'is turned on near T4 (at the time shown in FIG. 2 (e)) near the lowest temperature of the activated carbon in the fourth heater D'.
[0057]
The timing for turning off the fourth heater D ′ is the same as that for the fourth heater D in the first embodiment (turning off at time T7).
[0058]
The fourth heater D ′ is turned on and turned off when the rate of decrease in the temperature of the activated carbon in the fourth heater D ′ is equal to or lower than a predetermined value. Is turned off when the rate of increase in the value becomes equal to or less than a predetermined value (however, T7> T5).
[0059]
Since other canister structures and heater on / off operations are the same as those in the first embodiment, description thereof is omitted.
[0060]
As described above, the time TL from the on operation time T4 to the off operation is made longer than the time TS from the purge start time T0 to the on operation of the fourth heater D ', and the heating time by the fourth heater D' is increased. TL can be set to a value that can eliminate the remaining amount of evaporated fuel in the activated carbon closest to the atmosphere.
[0061]
Therefore, according to the second embodiment, in addition to the operation and effect of the first embodiment, the remaining amount of evaporated fuel in the activated carbon near the atmosphere introduction portion is almost eliminated, and the amount of HC released from the canister while the vehicle is stopped and It is possible to reduce the amount of fuel vapor blown during refueling.
[0062]
A canister provided with a heater to heat the activated carbon as in the first embodiment, a canister using the fourth heater D ′ as in the second embodiment, and a canister that does not heat the activated carbon The experimental result of the quantity is shown in FIG.
[0063]
FIG. 5 simulates purging while the vehicle is running, purging the canister with a constant air amount (about 100 to 200 times the amount of activated carbon of the canister), and then leaving it for about 12 hours, after which the canister 6 shows the amount of evaporative fuel released from the canister to the atmosphere (the amount of blow-through) with respect to the amount of evaporative fuel flowing into the canister when evaporative fuel is supplied to the canister. The ambient temperature was room temperature.
[0064]
As a result, the canister which was not heated showed the characteristic X, whereas the canister of the first embodiment showed the Y characteristic, and the canister of the second embodiment showed the Z characteristic.
[0065]
The phenomenon of blow-through from the canister is that the evaporated fuel remaining in the canister without being purged is pushed out to the atmospheric port by the inflow of evaporated fuel (mainly air in the evaporated fuel) that flows in from the tank port afterwards. It occurs in.
[0066]
Therefore, as in the first embodiment, in the canister in which the fourth heater D is provided to heat the activated carbon on the atmosphere side, the remaining amount of evaporated fuel in the activated carbon on the atmosphere side after the purge is compared with the canister that is not heated. The amount of blow-through (leakage amount) is small as shown by the characteristic Y, and particularly in the second embodiment, the activated carbon that adsorbs the evaporated fuel that is first pushed into the atmosphere when the vehicle is left is heated early and for a long time. As a result, the remaining amount of the evaporated fuel was made extremely small, so that the amount of the blown-through fuel (leakage amount) of the evaporated fuel was further reduced as compared with the first embodiment as indicated by the Z characteristic.
[0067]
Next, a third embodiment shown in FIG. 6 will be described.
[0068]
In the third embodiment, as in the second embodiment, a plurality of heaters A to D 'are arranged in the canister 1 and these are driven by a drive unit 15 having a CPU 14 at the same timing as in the second embodiment. In this third embodiment, a timer 16 is built in the CPU 14 without using the temperature sensors E to H, and the timer 16 is similar to the second embodiment. The heaters A to D ′ are turned on and off at the timing.
[0069]
Usually, the temperature change of the activated carbon in the canister at the time of purging is proportional to the change in the remaining amount of the evaporated fuel. Therefore, the remaining amount value most suitable for the start of heating and the end of heating of each activated carbon is obtained from the remaining amount of adsorbed fuel over time in the activated carbon of each heater insertion portion by experiment in advance, and this remaining amount value is obtained from each heater A. The CPU 14 stores the on-operation time and off-operation time of −D ′.
[0070]
For example, from the remaining amount of evaporated fuel in each heater insertion portion as shown in FIGS. 7B to 7E (the broken line indicates the remaining amount when not heated), the time points T1, T4, T2, which are suitable for the start of heating. T5 is obtained, and time points T7 to T10 suitable for the end of heating are obtained and set (stored) in the CPU 14.
[0071]
In the state of being mounted on the vehicle, at the time of purging, the timers 16 turn on the corresponding heaters A, D ', B, C at the time of the stored T1, T4, T2, T5, and T7 to At the time T10, the corresponding heaters D ′, C, B, A are turned off. As a result, each heater can be turned on and off at the same timing as in the second embodiment using the temperature sensor, and the same effects as in the second embodiment can be exhibited, and the control program can be simplified. Is possible.
[0072]
Note that the method of controlling each heater with the remaining amount of evaporated fuel in the third embodiment may be applied to the canister of the first embodiment and controlled at that timing.
[0073]
In each of the above embodiments, the number of heaters is four. However, the number is not limited to four, and it is desirable to provide at least three. In addition, although the PTC heater is used as the heater, on / off control may be performed at a predetermined timing using a heater such as a nichrome wire.
[0074]
【The invention's effect】
As described above, according to the first aspect of the present invention, at the time of purging, the activated carbon layer can be partially heated in an order suitable for purging, or the heating can be stopped. Therefore, the order of the on-operation of the heater, by sequentially turning on operation from the heater tank port and the purge port side, can reduce the purge time, and can prevent the deterioration of the A / F feedback controllability.
[0075]
Furthermore, the turn-off operation sequence of each heater is sequentially turned off from the heater on the atmosphere port side, so that the evaporated fuel purged from the atmosphere-side activated carbon at the end of the purge is re-adsorbed on the tank port and the purge port-side activated carbon. This can suppress the deterioration of the activated carbon. Furthermore, when the necessary heating period of the activated carbon in the vicinity of each heater portion has passed, each heater is sequentially turned off, so that power saving can be achieved.
[0076]
Further, as in the invention described in claim 2 , by turning on the atmosphere side heater with priority, the heating time of the activated carbon on the atmosphere side is lengthened, and the remaining amount of the evaporated fuel is almost eliminated. The amount of air blown into the atmosphere can be reduced.
[0077]
Further, according to the third and fourth aspects of the invention, it is possible to easily control the on / off operation timing of each heater.
[0078]
Moreover, according to the invention of Claim 5 , the heating apparatus which can achieve the heating method of the said Claim 1 thru | or 3 can be provided.
[0079]
And according to invention of Claim 6 , the heating apparatus which achieves the heating method of Claim 4 can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic view of a canister and a heating device showing a first embodiment of the present invention.
2A and 2B are diagrams for explaining the operation of the canister shown in FIG. 1, in which FIG. 2A is a diagram showing an operation sequence of turning on and off each heater, and FIGS. The figure which shows the temperature characteristic of activated carbon.
FIG. 3 is a schematic view of a canister and a heating device showing a second embodiment of the present invention.
4A and 4B are diagrams for explaining the operation of the canister shown in FIG. 3, in which FIG. 4A is a diagram showing an operation sequence of turning on and off each heater, and FIGS. The figure which shows the temperature characteristic of activated carbon.
FIG. 5 is a view showing the blow-through amount between a canister without a conventional heating device and the canisters according to the first and second embodiments of the present invention.
FIG. 6 is a schematic view of a canister and a heating device showing a third embodiment of the present invention.
7A and 7B are diagrams for explaining the operation of the canister shown in FIG. 6, wherein FIG. 7A is a diagram showing an on / off operation sequence of each heater, and FIG. 7B to FIG. The characteristic view which shows remaining amount.
[Explanation of symbols]
1 Canister 2 Cases 6 and 7 Activated carbon layer 9 Tank port 10 Purge port 12 Air port 14 Control circuit (CPU)
15 Driving device 16 Timer A to D, D 'Heater E to H, H' Temperature sensor

Claims (6)

In a canister having a tank port and a purge port on one end side of the activated carbon layer and an air port on the other end side, a plurality of heaters are provided in the activated carbon layer from one end side to the other end side of the activated carbon layer. arrangement, and the order of the on-operation of the heater, from one end of the heater of the active carbon layer was turned actuated toward the other end of the heater, the order of the off-operation from the other end of the heater at one end A heating method in a canister, wherein the heater is sequentially turned off toward the heater. In a canister having a tank port and a purge port on one end side of the activated carbon layer and an air port on the other end side, a plurality of heaters are provided in the activated carbon layer from one end side to the other end side of the activated carbon layer. arrangement to the one end of the heater of the active carbon layer, disposed intermediate the heater between the other end of the heater, the other end of the heater, so as to turn on operation in preference to the intermediate heater, A heating method in a canister, wherein the turn-off operation is sequentially turned off from the heater on the other end side toward the heater on the one end side. The heating method in a canister according to claim 1 or 2 , wherein the timing of the on operation and the off operation of each heater is determined by comparing the ratio of the temperature change of the activated carbon with respect to time and a preset set value. The method for heating in a canister according to claim 1 or 2 , wherein a timing of on-operation and off-operation of each heater is set by a timer. In the canister having a tank port and a purge port on one end side of the activated carbon layer and an air port on the other end side, a plurality of the activated carbon layers arranged from one end side to the other end side in the activated carbon layer A heater, a plurality of temperature sensors for detecting the temperature of the activated carbon in the vicinity of each heater, and a control circuit for individually controlling the ON operation timing and the OFF operation timing of each heater based on the detection temperature of each temperature sensor; A canister heating device. In the canister having a tank port and a purge port on one end side of the activated carbon layer and an air port on the other end side, a plurality of the activated carbon layers arranged from one end side to the other end side in the activated carbon layer heating apparatus in a canister, characterized in that it comprises a heater, a timer for controlling individually each on actuation timing and the off-operation timing of the plurality of heaters.

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