JP2003278611A - Heating method and device in canister - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten purge completion time, to reduce power consumption and to suppress deterioration of activated carbon without deteriorating A/F feedback controllability. <P>SOLUTION: A tank port 9 and a purge port 10 are provided on one end side of activated carbon layers 6 and 7. An atmospheric port 12 is provided at the other end side. A plurality of heaters A to D are arranged from the one end side of the activated carbon layers 6 and 7 to the other end side within the activated carbon layers 6 and 7. As for the order of an ON-operation of each heater A to D, the ON-operations are successively performed from the heater A on the one end side of the activated carbon layers 6 and 7 to the heater D on the other end side. As for the order of an OFF-operation, the OFF operations are successively performed from the heater D on the other end side toward the heater A on the one end side. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating method and a heating device in a canister for adsorbing and collecting evaporated fuel evaporated from a fuel tank mounted on a vehicle.

[0002]

2. Description of the Related Art Conventionally, in a canister for collecting evaporated fuel evaporated from a fuel tank mounted on a vehicle while the engine is stopped and purging (also called desorption) the intake pipe when the engine is started, There is known a canister that heats the activated carbon contained in the canister during purging to promote desorption of the evaporated fuel adsorbed by the activated carbon.

However, since the above-mentioned activated carbon has a characteristic that the higher the temperature is, the larger the desorption amount of the vaporized fuel adsorbed on the activated carbon is, therefore, when all the activated carbon is rapidly heated to a high temperature when the engine is started, At the start of purging, a large amount of evaporated fuel is purged in the canister, which deteriorates the A / F feedback controllability.

Therefore, conventionally, one heater is built in the canister, and the heater is heated for a predetermined time after the engine is started (at the start of purging) to heat the air-fuel mixture at the start of the engine (at the start of purging). A device for preventing enrichment is disclosed in, for example, Japanese Patent Application Laid-Open No. 63-150459.

Also, a canister having a plurality of heaters incorporated in an activated carbon layer is disclosed in, for example, Japanese Utility Model Publication 57-7515.
No. 4 publication.

[0006]

In any of the above-mentioned conventional techniques, all the heaters in the canister are turned off at the same time, so that the vaporized fuel desorbed at the activated carbon portion on the atmosphere port side at the end of the purge causes the tank port ( Purge port)
There is a problem that the activated carbon on the side of the tank port re-adsorbs and accelerates deterioration of the activated carbon on the side of the tank port.

In view of the above, the present invention provides a plurality of heaters and controls the order of on-operation and off-operation of these heaters to shorten the purge completion time and reduce the power consumption. An object of the present invention is to provide a heating method and a heating device for a canister capable of suppressing deterioration of activated carbon due to such re-adsorption.

[0008]

In order to solve the above-mentioned problems, the first invention according to claim 1 is to provide a tank port and a purge port on one end side of the activated carbon layer and an atmospheric port on the other end side. In the provided canister, a plurality of heaters are arranged in the activated carbon layer from one end side to the other end side of the activated carbon layer, and each heater is turned on and off in a predetermined order. Is a heating method in a canister.

According to the present invention, during the purging, the heaters are individually turned on and off in a predetermined order to partially heat the activated carbon layer in the order suitable for purging, and the heating thereof. You can stop.

According to a second aspect of the present invention, in the first aspect of the present invention, the ON operation order of the heaters is sequentially turned on from the heater on one end side of the activated carbon layer toward the heater on the other end side. It is a heating method in a canister that is activated.

In the present invention, at the start of purging, the heaters are sequentially turned on from the heaters on the tank port side and the purge port side, so that heating is started from the activated carbon side having a large amount of evaporated fuel adsorbed. The purge completion time is shortened, and all activated carbon is not heated at the same time at the start of purging.
It is possible to prevent deterioration of F feedback controllability.

According to a third aspect of the present invention, in the first aspect of the present invention, the ON operations of the heaters are sequentially turned on from the heater on one end side of the activated carbon layer toward the heater on the other end side. This is a heating method for a canister in which the operation is performed and the OFF operation is sequentially performed from the heater on the other end side to the heater on the one end side.

Further, in the present invention, the order of turning off the heaters is such that the heaters on the other end side having the atmospheric port are sequentially turned off toward the heaters on the one end side. Re-adsorption of the evaporated fuel purged from the heated activated carbon on the other end side to the activated carbon on the one end side is suppressed.

According to a fourth aspect of the present invention, in the first aspect of the present invention, 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 other end side is arranged. The heating method in the canister is such that the heater of No. 3 is turned on with priority over the intermediate heater, and the order of turning off is sequentially turned off from the heater on the other end side to the heater on the one end side. .

Further, according to the present invention, the heating time of the activated carbon on the side of the atmospheric port at the time of purging can be lengthened so that the remaining amount of evaporated fuel in the activated carbon can be almost eliminated. The amount of vaporized fuel released can be reduced, and the amount of vaporized fuel blown into the atmosphere when the vaporized fuel is introduced during refueling of gasoline can be reduced.

A fifth invention according to claim 5 is the invention according to any one of the first to fourth inventions, wherein the timing of the on-operation and the off-operation of each of the heaters is a ratio of the temperature change of the activated carbon to the time. It is a heating method for a canister, which is determined by comparing a predetermined value with a preset value.

According to a sixth aspect of the invention, in the invention according to any one of the first to fourth aspects, the canister is configured to set a timing of ON operation and OFF operation of each heater by a timer. Is the heating method.

By controlling the on-operation timing and off-operation timing of each heater as in the fifth or sixth invention, the control becomes easy.

A seventh aspect of the present invention is a canister in which a tank port and a purge port are provided at one end of an activated carbon layer and an atmospheric port is provided at the other end of the activated carbon layer. A plurality of heaters arranged from one end side to the other end side, a plurality of temperature sensors for detecting the temperature of the activated carbon in the vicinity of each heater, and on-operation timing of each heater based on the detected temperature of each temperature sensor And a heating device in a canister, which has a control circuit for individually controlling the off operation timing.

According to the present invention, the heating methods of the first to fifth inventions can be achieved.

According to an eighth aspect of the present invention, in 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, the activated carbon layer is formed in the activated carbon layer. A heating device for a canister, comprising: a plurality of heaters arranged from one end side to the other end side; and a timer for setting an ON operation timing and an OFF operation timing of the plurality of heaters.

According to the present invention, the heating method of the sixth invention can be achieved.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described with reference to the examples shown in the drawings.

1 and 2 show a first embodiment.

FIG. 1 is a schematic view of a heater, which is a heating means in the present invention, and a canister showing an arrangement state of temperature sensors.

In FIG. 1, the case 2 forming the canister 1 is divided 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.

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.
The tank port 9 is connected to a fuel tank (not shown) so that the evaporated fuel in the fuel tank is introduced into the canister 1 from the tank port 9. Further, the purge port 10 is connected to an intake pipe of an engine (not shown).

A chamber 11 is provided on one side of the second activated carbon layer 7.
The atmospheric port 12 is provided via the
Atmosphere is introduced into the canister 1.

The other sides of the first activated carbon layer 6 and the second activated carbon layer 7 are communicated with each other through a chamber 13.

Both of the activated carbon layers 6 and 7 are formed in a U-shape in series, and when viewed from the entire 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 other end. The atmospheric port 12 is arranged on the side.

A plurality of heaters are provided in the activated carbon layers 6 and 7. In the embodiment shown in the figure, two heaters A and B are provided in the first activated carbon 6 and the second activated carbon layer 7 is provided. Two heaters C and D are provided in the. In addition, these heaters A to
D is a PTC heater in this embodiment, and canister 1
The heaters A are arranged in a U-shape in series along the flow of evaporated fuel and air inside, and the heater A is arranged at one end side which is the tank port 9 (purge port 10) side in the activated carbon layer, and the heater D is It is arranged on the other end side of the activated carbon layer which is the atmospheric port 12 side, and an intermediate heater B,
C is placed. Of these heaters, the heater closest to the tank port 9 (purge port 10) is the first heater.
Heater A from the first heater A to the atmospheric port 12
The heaters sequentially arranged to the second side are the second heater B and the third heater.
Heater C and fourth heater D.

Each of the heaters A to D is a control circuit (CPU)
On / off control is performed at a predetermined timing, which will be described later, by a signal from a driving device 15 provided with 14.

In the activated carbon layers 6 and 7, the heaters A to
A plurality of temperature sensors E to H such as thermocouples for detecting the temperature of the activated carbon near D are arranged. In the illustrated embodiment, the flow direction of the evaporated fuel from the tank port 9 (purge port 10) to the atmospheric port 12 is shown. Is arranged on the upstream side of each heater. The signals of 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 operation. ON / OFF operation of the heater B is controlled, ON / OFF operation of the third heater C is controlled by the third temperature sensor G, and ON / OFF operation of the fourth heater D is controlled by the fourth temperature sensor H. It is controlled.

Next, the operation will be described.

While the engine is stopped, the heaters A to D are off, and the vaporized fuel introduced from the tank port 9 passes from the portion of the first activated carbon layer 6 on the tank port 9 side to the atmospheric port of the second activated carbon layer 7. It is sequentially adsorbed and collected on the 12-side portion. Therefore, a larger amount of evaporated fuel is adsorbed and collected by the activated carbon on the side of the tank port 9 than the other portions.

Next, when the engine is started, negative pressure in the intake pipe 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 removed. It is separated from the activated carbon and is purged together with air from the purge port 10.

Regarding the heating operation timing of each heater A to D at the time of this purge, heating is started from the first heater A, then the second heater B, the third heater C, and the fourth heater D. The heating operation is performed by sequentially delaying the time until the heating starts. FIG. 2 shows the ON operation timing of each heater A to D.
Will be described.

First, as shown in FIG. 2 (b), at the time T1 at which the temperature decrease rate of the activated carbon in the first temperature sensor E reaches a predetermined value from the start of purge T0, as shown in FIG. 2 (a). Thus, the first heater A is turned on. At this time T
The reason why 1 is determined from the temperature drop rate of activated carbon is
The temperature of the activated carbon during purging depends on the outside air temperature, the adsorbed state of the evaporated fuel, and the like, so that it cannot be turned on at a specific temperature. Therefore, paying attention to the fact that the activated carbon temperature decreases due to the latent heat of vaporization of the evaporated fuel with the start of purging, the CPU calculates the temperature decrease rate, and turns on when the decrease rate becomes less than the set value. It is a thing. That is, as shown in FIG. 2B, the temperature drop curve of the activated carbon from the time T0 of starting the purge becomes gradual with the passage of time (the broken line shows the temperature assuming no heating). The measured temperature (which is output as a voltage in this embodiment) is sampled by the CPU 14 at constant sampling intervals, and the temperature change amount for each sampling is set to a preset falling rate setting value (hereinafter, referred to as the first
(Abbreviated as the set value of 1) or less), the first heater A is turned on.

Next, since the activated carbon of the second temperature sensor F portion also has the same temperature decrease curve as described above, the temperature measured by the second temperature sensor F is measured by the CPU 14 at regular sampling intervals. Sampling is performed, and the second heater B is turned on when the amount of temperature change for each sampling becomes 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 delayed from the time T1 when the first heater A is turned on.

Next, the third temperature sensor G section and the fourth temperature sensor H section will be described.

As shown in FIGS. 2 (d) and 2 (e), the temperature of the activated carbon in these temperature sensors G and H is lowered by the latent heat of vaporization at the start of purging, and it is considered that the desorption of the evaporated fuel is completed. It becomes the minimum temperature at the time of T3 and T4. Then, after that, the latent heat of vaporization of the evaporated fuel disappears, so that the temperature of the activated carbon rises so as to approach the ambient temperature. At this time, the temperature rise curve becomes gentle with the passage of time as shown in FIGS. Furthermore, the lowest temperature point T4 in the fourth temperature sensor H section is earlier than the lowest temperature point T3 in the third temperature sensor G section, and the temperature curve after the point T4 is higher than the temperature curve after the point T3. Get loose.

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 the temperature change amount for each sampling is set to a preset rising rate setting value ( Hereinafter, the third heater C is turned on when the value becomes equal to or more than the third set value). As a result, the third heater C can be heated at the time T5, which is delayed from the on-operation time T2 of the second heater B.

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. The fourth heater D is turned on when it becomes equal to or larger than the fourth set value smaller than the third set value of. As a result, the fourth heater D is connected to the third heater
The heating operation can be performed at time T6, which is delayed from the time T5 at which the heater C is turned on.

From the above, the heaters A to D are arranged as shown in FIG.
As shown in, the ON operation is sequentially performed after a predetermined time.

As described above, from the first heater A on the tank port 9 (purge port 10) side to the fourth heater A on the atmosphere port side.
Since the heater D is turned on in sequence sequentially, the adsorbed amount of evaporated fuel is large, a large amount of purge air is required to complete the purge, and it takes time to complete the purge. The activated carbon on the 10) side is heated first, and it is possible to shorten the purge completion time.

Further, since not all activated carbons are heated at the same time, it is possible to prevent a large amount of evaporated fuel from being purged at the start of purging, and prevent the air-fuel mixture from becoming too concentrated at the start of purging (when the engine is started). A / F feedback controllability is not deteriorated.

Next, the timing of turning off the heaters A to D will be described.

After all of the heaters A to D have been turned on, and after a predetermined time has passed, 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 after a certain time toward the heater on the tank port 9 (purge port 10) side.

The OFF operation timing of each of the heaters D to A will be described with reference to FIG.

The temperature of the activated carbon in the vicinity of the time T6 after the fourth heater D is turned on as described above, that is, the temperature rise curve of the fourth temperature sensor H is shown in FIG.
As shown in (e), the heater reaches the Curie point after the rapid completion and the curve becomes gentle. Therefore, the temperature measured by the fourth temperature sensor H (which is output as a voltage in this embodiment) is sampled by the CPU 14 at a constant sampling interval as in the above-described ON operation, and the temperature for each sampling is measured. 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 a fifth setting value).

Next, the third heater C, the second heater B,
Times T5, T2, T when the first heater A is turned on
Figure 2 also shows the temperature curve of activated carbon in the vicinity after 1
As shown in (G), (F), and (E), since the temperature becomes gentler with the passage of time, the rate of temperature rise is equal to or lower than the sixth to eighth set values set in the same manner as the fourth heater D. At times T8, T9, and T10 at which the value becomes, the off operation is performed.

As a result, as shown in FIG. 2A, the off operation is sequentially performed from the fourth heater D on the atmosphere side toward the first heater A on the tank port 9 (purge port 10) side. To do.

With the above-described off operation, each heater is sequentially turned off after the heating time required for purging in that portion has passed, so that low power consumption (power saving) can be achieved.

Furthermore, since heating is sequentially stopped from the activated carbon on the upstream side (atmosphere port 12 side) of the flow of purge air,
At the end of the purge, it is possible to suppress re-adsorption of the high boiling point evaporated fuel purged by the activated carbon on the upstream side to the activated carbon on the downstream side (tank port 9 side), and the activated carbon, particularly the tank port 9 (purge port 10). The deterioration of the activated carbon on the side can be prevented.

3 and 4 show the second embodiment.

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 of the activated carbon layer near the atmosphere introducing portion where the activated carbon can be sufficiently heated. 4 heater D ',
A temperature sensor H'is arranged near the fourth heater D ',
The ON operation of the fourth heater D'is performed with priority over the ON operation sequence of the first embodiment. In other words, the second heater B and the third heater C in the middle are preferentially activated earlier than the intermediate heaters B and C. For example, as shown in FIG. 4 (e), the fourth heater D'is turned on near the minimum temperature T4 of the activated carbon in the fourth heater D'part (time point shown in FIG. 2 (e)).

The OFF operation timing of the fourth heater D'is the same as that of the fourth heater D in the first embodiment (OFF operation is performed at time T7).

The ON operation and OFF operation timing of the fourth heater D'is similar to the above, when the lowering rate of the temperature of the activated carbon in the fourth heater D'is less than a predetermined value. Then, when the temperature rise rate becomes equal to or lower than a predetermined value, the off operation is performed (however, T7> T5).

Since the other structure of the canister and ON / OFF operation of the heater are the same as those in the first embodiment,
The description is omitted.

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 of the fourth heater D'to the ON operation, and the fourth heater D'is increased. The heating time TL can be set to a value that can eliminate the remaining amount of the evaporated fuel in the activated carbon closest to the atmosphere.

Therefore, according to the second embodiment, in addition to the function and effect of the first embodiment, the remaining amount of the evaporated fuel in the activated carbon near the atmosphere introducing portion is almost eliminated, and the HC from the canister while the vehicle is stopped is reduced. It is possible to reduce the discharge amount and the blow-through amount of the evaporated fuel during refueling.

As in the first embodiment, a canister provided with a heater for heating activated carbon, and a canister using the fourth heater D'as in the second embodiment,
The experimental results of the blow-through amount of the canister without heating the activated carbon are shown in FIG.

FIG. 5 simulates purging while the vehicle is running, and a constant air amount (about 100 to 2 with respect to the activated carbon capacity of the canister) is used.
The canister is purged with (00 times the amount of air), then left for about 12 hours, and then the evaporated fuel from the canister to the atmosphere with respect to the inflow amount of the evaporated fuel into the canister when the evaporated fuel is supplied to the canister. The amount of discharge (blowing amount) is shown. The ambient temperature was room temperature.

As a result, the characteristic of the canister which is not heated is X, whereas the characteristic of the canister of the first embodiment is Y, and the characteristic of the canister of the second embodiment is Z.
The characteristics of

The blow-through phenomenon from the canister is that the vaporized fuel remaining in the canister without being completely purged enters the atmospheric port due to the inflow of vaporized fuel (mainly air in the vaporized fuel) which is subsequently flown from the tank port. It is caused by being pushed out.

Therefore, as in the first embodiment, the fourth
In the canister which is provided with the heater D and heats the activated carbon on the atmosphere side, the blow-through amount (leakage amount) is smaller than that of the unheated canister because the remaining amount of the evaporated fuel in the activated carbon on the atmosphere side is small. In particular, in the second embodiment, the activated carbon that adsorbs the evaporated fuel that is first pushed out into the atmosphere when the vehicle is left standing is heated early and for a long time so that the remaining amount of the evaporated fuel is extremely reduced. Therefore, the blow-through amount (leakage amount) of the evaporated fuel was further smaller than that in the first embodiment as indicated by the Z characteristic.

Next, a third embodiment shown in FIG. 6 will be described.

In the third embodiment, as in the second embodiment, a plurality of heaters A to D'are arranged in the canister 1, and the heaters A to D'are arranged in the drive unit 15 equipped with the CPU 14 in the same manner as in the second embodiment. However, in the third embodiment, a timer 16 is built in the CPU 14 without using the temperature sensors E to H, and the second embodiment uses the timer 16 to operate. The heaters A to D'are turned on and off at the same timing.

Normally, the temperature change of the activated carbon in the canister and the remaining amount of the evaporated fuel during purging are proportional. Therefore, by an experiment, a residual amount value most suitable for starting and ending the heating of each activated carbon is obtained from the residual amount of the adsorbed fuel in the activated carbon of each heater insertion portion in advance, and the residual amount value is calculated for each heater A. The on-operation timing and off-operation timing of -D 'are stored in the CPU 14.

For example, from the remaining amount of the evaporated fuel in each heater insertion portion (the broken line shows the remaining amount when not heating) as shown in FIGS. , T2, T5, and the time points T7 to T10 suitable for ending heating are set and stored (stored) in the CPU 14.

Then, in the state of being mounted on the vehicle, at the time of purging, the stored T1, T
4, the corresponding heaters A, D ', B, at the times of T2, T5,
C is turned on, and the corresponding heaters D ', C, B and A are turned off at the time points T7 to T10. This allows
Each heater can be turned on and off at the same timing as in the second embodiment using the temperature sensor to achieve the same effect as in the second embodiment, and the control program can be simplified. Become.

The method of controlling each heater by the remaining amount of the evaporated fuel of the third embodiment may be applied to the canister of the first embodiment to control at that timing.

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 or more. Also, the heater is PTC
Although the heater is used, a heater such as a nichrome wire may be used to perform on / off control at a predetermined timing.

[0074]

As described above, according to the first aspect of the present invention, the activated carbon layer is partially removed during purging.
The heating can be carried out in an order suitable for purging, or the heating can be stopped. Therefore, as in the second aspect of the invention, by sequentially turning on the heaters in the order of turning on the heaters on the tank port side and the purge port side, the purge time can be shortened and the A / F feedback control can be performed. The deterioration of sex can be prevented.

Further, as in the third aspect of the present invention, the 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 activated carbon on the atmosphere side at the end of the purge. Suppresses re-adsorption of activated carbon on the tank port and purge port side,
It is possible to suppress deterioration of activated carbon. Furthermore, after the required heating period of the activated carbon near each heater portion has passed, each heater is sequentially turned off to save power.

Further, as in the invention described in claim 4, by preferentially turning on the heater on the atmosphere side, the heating time of the activated carbon on the atmosphere side is lengthened to almost eliminate the remaining amount of the evaporated fuel, The amount of vaporized fuel blown into the atmosphere can be reduced.

According to the fifth and sixth aspects of the invention, it is possible to easily control the ON / OFF operation timing of each heater.

According to the invention described in claim 7, it is possible to provide a heating device capable of achieving the heating methods described in the first to fifth aspects.

According to the invention described in claim 8,
A heating device that achieves the heating method according to claim 6 can be provided.

[Brief description of 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 ON / OFF operation sequence of each heater, and FIGS. The figure which shows the temperature characteristic of activated carbon.

FIG. 3 is a schematic diagram of a canister and a heating device showing a second embodiment of the present invention.

4A and 4B are views for explaining the operation of the canister shown in FIG. 3, in which FIG. 4A is a view 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 diagram showing blow-through amounts of a conventional canister without a heating device and the canisters of 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 views for explaining the operation of the canister shown in FIG. 6, in which FIG. 7A is a view showing an operation sequence of turning on and off each heater, and FIGS. The characteristic view which shows a residual amount.

[Explanation of symbols]

1 canister 2 cases 6,7 Activated carbon bed 9 Tank port 10 Purge port 12 atmospheric ports 14 Control circuit (CPU) 15 Drive 16 timers A to D, D'heater E to H, H'temperature sensor

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor ▲ Yoshi ▼ Mamoru Oka             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. (72) Inventor Shinsuke Kiyomiya             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. F-term (reference) 3G044 BA32 BA40 CA03 DA06 EA10                       FA12 GA29

Claims (8)

[Claims] 1. A canister in which a tank port and a purge port are provided on one end side of an activated carbon layer and an atmospheric port is provided on the other end side, in the activated carbon layer, from one end side to the other end side of the activated carbon layer. A heating method for a canister, wherein a plurality of heaters are arranged, and each heater is turned on and off in a predetermined order. 2. The heating method for a canister according to claim 1, wherein the heaters are turned on in sequence from the heater on one end side of the activated carbon layer toward the heater on the other end side. 3. The ON operation sequence of each heater is sequentially ON operation from the heater on one end side of the activated carbon layer toward the heater on the other end side, and the OFF operation sequence is from the heater on the other end side to one end side. The heating method for a canister according to claim 1, wherein the heaters on one side are sequentially turned off. 4. An intermediate heater is arranged between the heater on one end side and the heater on the other end side of the activated carbon layer, and the heater on the other end side is turned on with priority over the intermediate heater. 2. The turn-off operation is performed sequentially from the heater on the other end side toward the heater on the one end side.
The heating method for a canister according to [4]. 5. 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 heating method for a canister according to [4]. 6. The heating method for a canister according to claim 1, wherein the timing of on-operation and off-operation of each heater is set by a timer. 7. 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, in the activated carbon layer, from one end side to the other end side of the activated carbon layer. A plurality of heaters arranged, 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 timing of each heater are individually controlled based on the detected temperature of each temperature sensor. A heating device in a canister having a control circuit. 8. 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, in the activated carbon layer, from one end side to the other end side of the activated carbon layer. A heating device for a canister, comprising: a plurality of arranged heaters; and a timer for setting an ON operation timing and an OFF operation timing of the plurality of heaters.