JP2003314382A - Evaporation fuel treating equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an evaporation fuel treating equipment easily finding a trouble, if some trouble occurs in a heating device of a canister and preventing leakage of evaporation fuel to the atmosphere. <P>SOLUTION: A purge fuel concentration detecting means (for example, A/F (air-to-fuel) sensor 10) is provided in a purge passage 9b, a concentration difference before/after the energization to a heating device (heater 5, etc.), is compared with a set value and, when the concentration difference is smaller than the set value, the heating device is determined to be in the trouble. When some trouble occurs in the heating device of the canister 2, this device easily discovers it and prevents the leakage of the evaporation fuel to the atmosphere. <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 fuel vapor treatment system for an automobile, and more particularly to a failure determination of a system for heating an adsorbent contained in a canister.

[0002]

2. Description of the Related Art Evaporative fuel generated in a fuel tank of an automobile is temporarily adsorbed by an adsorbent contained in a container and desorbed by a negative pressure suction force of an engine to prevent the evaporated fuel from leaking to the atmosphere. An evaporative fuel processing apparatus which has an improved adsorption / desorption efficiency of a canister to improve the processing capacity is known from Japanese Utility Model Laid-Open No. 61-147358.
According to this publication, a sheath heater is housed in a container filled with activated carbon for adsorbing fuel vapor,
It is said that the desorption performance of the canister is improved by heating the activated carbon with a sheath heater.

[0003]

[Problems to be Solved by the Invention] However, by any chance,
If the heating device fails, the appearance cannot be confirmed. Also, the malfunction of the canister is difficult to affect the drivability of the vehicle, so the discovery of the malfunction is delayed, and the adsorption of the canister
The desorption performance may deteriorate and the evaporated fuel may leak to the atmosphere. Therefore, the present invention makes it possible to easily detect even if a failure occurs in the heating device of the canister by some kind of abnormality detecting means and prevent the evaporated fuel from leaking to the atmosphere. The challenge is to provide.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the invention of claim 1 temporarily adsorbs the evaporated fuel generated in the fuel system and desorbs it during engine operation to prevent leakage to the atmosphere. In the evaporated fuel processing apparatus including the heating device, the heating device is provided with an abnormality detecting means, and the failure of the heating device is determined based on the value detected by the abnormality detecting means. Further, the invention of claim 2 is characterized in that the abnormality detecting means is a concentration detecting means. According to a third aspect of the present invention, when the heating device is energized, the concentration detecting means detects the purge fuel concentration immediately before energization, and after the heating device is energized, the purge fuel concentration is detected to preset the difference between the two concentrations. It is characterized in that it is compared with the set value set aside, and if it is smaller than the set value, it is determined that the heating device has failed.

The invention of claim 4 is characterized in that the abnormality detecting means is current / voltage detecting means. According to the invention of claim 5, the current value or the voltage value detected by the current / voltage detecting means is compared with a preset value, and if the difference from the preset value is larger than the judgment value, It is characterized in that it is judged as a failure of the heating device.

The invention of claim 6 is characterized in that the abnormality detecting means is a temperature detecting means. Further, according to the invention of claim 7, when there is no change in the output of the temperature detecting means when the heating device is energized, it is determined that the heating device has failed, and even if there is an output change, the output change amount is preset. If the difference from the set value is larger than the determination value, it is determined that the function of the heating device has deteriorated.

According to an eighth aspect of the present invention, in an evaporative fuel processing apparatus provided with a heating device for temporarily adsorbing the evaporated fuel generated in the fuel system and desorbing it during engine operation to prevent leakage to the atmosphere, the same adsorption of the canister. It is characterized in that a pair of heating elements arranged in the material chamber is connected by a bridge circuit, and a failure and a functional deterioration of the heating device are determined based on a current value flowing in the bridge circuit.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described with reference to the drawings. First, a first embodiment of the present invention corresponding to claims 1 to 3 will be described. FIG. 1 is a vertical sectional view of an evaporated fuel processing apparatus according to a first embodiment of the present invention, and FIG. 2 is a flowchart showing a failure detection routine of the heating apparatus. In FIG. 1, an adsorbent 4 is provided in a case 3 that constitutes a canister 2 of the evaporated fuel processing apparatus 1.
The first adsorbent chamber 2a and the second adsorbent chamber 2b are partitioned by the partition wall 3a. A heat radiating member 7 to which a heater 5 constituting a heating device is fixed is embedded in a substantially central portion of the adsorbent 4 in the first adsorbent chamber 2a. The heater 5 is connected to an ECU 6 having a built-in heater driving circuit and a power supply circuit via a wiring 5a, and electric power is controlled by an electric signal from the ECU 6.

A purge port 3b and a tank port 3c are provided upright on the upper part of the case 3 on the side of the first adsorbent chamber 2a.
The purge port 3b communicates with a downstream portion of the throttle valve 9a of the intake pipe 9 via a VSV (vacuum switching valve) 8 for adjusting the amount of evaporated fuel passing by duty control. VSV8 is EC via wiring 8a
It is configured to be activated by an electrical signal from U6. Purge passage 9 between the purge port 3b and the intake pipe 9
A concentration detecting means for detecting the concentration of the vaporized fuel (vapor) passing therethrough, for example, an A / F sensor 10 is provided in b, and is electrically connected to the ECU 6. The tank port 3c communicates with the upper part of the fuel tank. Second adsorbent chamber 2
Atmosphere port 3d is erected on the upper part of case 3 on the b side,
It is constructed so that fresh air is introduced from the atmosphere during desorption. The heating device of the present invention includes a heater 5, a heat dissipation member 7,
It is composed of the ECU 6, the A / F sensor 10, and the like.

Next, the operation of the first embodiment will be described with reference to FIG.
The description will be made with reference to FIG. 1 and 2, the steps of the flowchart (hereinafter, simply referred to as S)
At 100, it is checked whether the heater 5 needs to be energized, that is, whether the purge is started and the heating by the heater 5 may be started. As a check method, for example, there is a method of detecting the engine speed, the pressure in the intake pipe, the lubricating oil pressure, the vapor (evaporated fuel) concentration, and the like. In the present embodiment, the abnormality detection means is provided in the purge passage 9b. The vapor concentration is detected using the A / F sensor 10. When it is determined in S100 that the heater 5 needs to be energized, the vapor concentration is detected by the A / F sensor 10 in S101, and the A value is determined by the ECU.
It is stored and stored in.

Next, in step S102, the heater 5 is turned on to start heating. After a lapse of a predetermined time after the heater 5 is turned on, the vapor concentration is detected again in S103 and stored as a B value in the ECU. Then S10
4, the difference between the A and B values stored, that is, B-A, is compared with a preset value C that has been preset by experiments or the like. When BA is larger than the set value C, S10
In 6 the function of the heater 5 is determined to be normal, and if it is small, the function of the heating device including the heater 5 is determined to be defective in S107. As described above, the abnormality is notified to the driver by the abnormality lamp (not shown) or the like, so that the failure of the heating device can be easily found. In addition, the failure of the heating device
It is possible to make an indirect determination by using the / F sensor.

Next, a second embodiment of the present invention corresponding to claims 1, 4 and 5 will be described. FIG. 3 is a vertical sectional view of an evaporated fuel processing apparatus according to a second embodiment of the present invention, and FIG. 4 is a flowchart showing a failure detection routine of the heating apparatus. In FIG. 3, E of the evaporated fuel processing device 11
The CU 60 has a built-in current / voltage detecting means 60a for detecting the control current or control voltage of the heater power supply circuit. Since other configurations are similar to those of the first embodiment, the same functional parts are designated by the same reference numerals and the description thereof will be omitted.

Next, the operation of the second embodiment will be described with reference to FIG.
And it demonstrates with reference to FIG. 3 and 4, in S200 of the flow chart, whether or not the heater 5 needs to be energized, that is, the purge is started and the heater 5 is started.
It is checked whether the heating by can be started. As a checking method, for example, the engine speed, the intake pipe pressure, the lubricating oil pressure, etc. are detected. When it is determined in S200 that the heater 5 needs to be energized, the heater 5 is turned on and heating is started in S201.

Next, in S202, it is determined whether or not the energization of the heater 5 is normal. If not, it is determined in S203 that the heating device including the heater 5 has a failure. If the energization is normal, the process proceeds to S204, where the difference between the applied current value or voltage value of the heater 5 and the set value A set in advance by experiments or the like, that is, the deviation from the set value A is the judgment value B.
When the deviation from the set value A is smaller than the judgment value B, the function of the heater 5 is judged to be normal in S205. If the deviation from the set value A is larger than the determination value B, S2
At 06, it is determined that the function of the heater 5 has failed. As described above, not only the failure of the heating device can be determined as in the first embodiment, but also the function of the heater itself can be determined.

Next, a third embodiment of the present invention corresponding to claims 1, 6 and 7 will be described. FIG. 5 is a vertical sectional view of an evaporated fuel processing apparatus according to a third embodiment of the present invention, and FIG. 6 is a flowchart showing a failure detection routine of the heating apparatus. In FIG. 5, the heater 25 of the evaporated fuel processing device 31 is connected to the ECU 61 via the wiring 25a.
The power is controlled by the power supply from the CU 61. Heater 25
A temperature detecting means 28 for detecting the temperature of the heater 25 including, for example, a bimetal switch, a thermistor thermometer, and the like is provided in the vicinity of. The temperature detecting means 28 is the wiring 2
8a is connected to the ECU 61, and the detection signal is the ECU
It is configured to be sent to 61. A failure of the heating device is determined based on this detection signal. Since other configurations are the same as those of the first embodiment, the same functional parts are designated by the same reference numerals and the description thereof will be omitted.

Next, the operation of the third embodiment will be described with reference to FIG.
And it demonstrates with reference to FIG. 5 and 6, in step S300 of the flowchart, the O of the heater 25 is turned off.
It is determined whether N or OFF switching is necessary. That is, if it is determined that the heater 25 needs to be switched, S3
Proceeding to 01, the heater 25 is switched on or off. Next, in S302, it is determined whether or not there is a time-dependent change in the output of the temperature detecting means 28. If there is no change in the output, it is determined in S303 that the heating device including the heater 25 has failed. If there is a change in output over time, S3
In 04, the difference (deviation) between the output change and the preset value A set in advance by experiments or the like is compared with the determination value B. If the difference from the set value A is smaller than the judgment value B, it is judged in S305 that the function of the heater 25 is normal, and if it is larger than the judgment value B, it is judged in S306 that the function of the heater 25 is deteriorated. As described above, the same effect as in the second embodiment is produced, and the actual temperature of the heater is detected, so that the determination can be accurately performed.

Next, a fourth embodiment of the present invention corresponding to claims 1 and 8 will be described. FIG. 7 is a vertical sectional view of an evaporated fuel processing apparatus according to a fourth embodiment of the present invention, FIG. 8 is a bridge circuit for detecting a failure of the heating apparatus, and FIG.
Is a graph (current value-time diagram) showing a threshold value (setting value) for failure determination, and FIG. 10 is a flowchart showing a failure detection routine of the heating device. In FIG. 7, a pair of heaters A1 are provided on the heat dissipation member 7 of the evaporated fuel processing device 41.
5. The heater B16 is fixed. The heater A15 and the heater B16 are connected to the ECU 62 via wirings 15a and 16a, and in the ECU 62, a Wheatstone bridge circuit (abbreviated as bridge circuit) 62a as shown in FIG.
Is configured. Since other configurations are the same as those of the first embodiment, the same functional parts are designated by the same reference numerals and the description thereof will be omitted.

Next, the operation of the fourth embodiment will be described with reference to FIGS. 7, 8 and 9. 8 and 9, by monitoring the current value I flowing in the bridge circuit 62a formed between the heater A15 and the heater B16 placed in the first adsorbent chamber 2a of the canister 2, the heater A15 and the heater B16 are monitored. Either failure can be detected. That is, in FIG. 9, the current value I is the set value A.
When it is within the range of 1 to A2, it can be determined that neither the heater A15 nor the heater B16 is abnormal. That is, it is determined that there is no abnormality in the heating device. If the current value I is equal to or greater than the set value B1 in the + direction, it can be determined that the heater A15 has failed, and if the current value I is equal to or less than the set value B2 in the − direction, it can be determined that the heater B16 has failed. it can. Further, the current value I is from the set value A1 in the + direction to B1
When it is within the range of A, it can be determined that the function of the heater A15 itself has deteriorated, and when it is within the range of the set values A2 to B2 in the-direction, it can be determined that the function of the heater B16 itself has deteriorated.

Next, the failure detection routine of the heating apparatus of the fourth embodiment will be described with reference to FIG. S400
It is checked whether or not the heater needs to be energized, and if it is determined that it is necessary, the power is supplied to the heaters A15 and B16 to start heating in S401. S40
2, the current value I is checked, and if it is within the range of the set values A1 to A2, the heaters A15 and B are set in S403.
16 is determined to be normal. The current value I is the set value A1 to A2
If it is out of the range, the process proceeds to S404, and it is checked whether the current value is in the + direction. When the current value is in the + direction, the current value I is compared with the set value B1, and when it is larger than B1, it is determined in S406 that the heater A15 has failed. If it is smaller than B1, heater A in S407
It is determined that the number of functions is 15. If the current value is in one direction in S404, the current value I is compared with the set value B2 in S408. If it is smaller than B2, it is determined in S409 that the heater B16 has failed, and if it is larger than B2, the heater B16 is in S410. It is judged that the function of is deteriorated. As described above, in addition to the effects of the third embodiment,
In the case of using a pair of heaters, it is not necessary to provide an abnormality detecting means for each, and it is possible to simplify the heating device and the failure detection routine program.

[0020]

Since the present invention is configured as described above, it has the following effects. That is, according to the first to third aspects of the invention, the heating device is provided with the abnormality detecting means, and the heating device is determined to be defective based on the value detected by the abnormality detecting means. Even if a failure occurs, it can be easily detected and the leakage of evaporated fuel to the atmosphere can be prevented.

Further, in the inventions of claims 4 and 5, the heating device is provided with a current / voltage detecting means, and when the difference between the detected current value or voltage value and the set value is larger than the judgment value, the heating device fails. Therefore, even if a failure occurs in the heating device of the canister, it can be easily detected and the leakage of evaporated fuel to the atmosphere can be prevented. Further, not only the failure of the heating device but also the failure of the function of the heater itself can be found.

According to the present invention, the temperature detecting means is provided in the vicinity of the heating element, and there is no change in the output of the temperature detecting means when the heating device is energized, or even if there is an output change amount and the set value. If the difference is larger than the judgment value, it is determined that the heating device has failed or has deteriorated.Therefore, even if a failure occurs in the heating device of the canister, the heating element is directly detected. It can be easily found without making an erroneous judgment, and the leakage of evaporated fuel to the atmosphere can be prevented.

According to the invention of claim 8, the failure of the heating device is judged based on the current value flowing by connecting a pair of heating elements arranged in the same adsorbent chamber of the canister with a bridge circuit. Since this is done, even if a failure occurs in the heating device of the canister, it can be easily detected and leakage of evaporated fuel to the atmosphere can be prevented. Furthermore, although a pair of heaters is used, it is not necessary to provide an abnormality detecting means for each, and the heating device can be simplified.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an evaporated fuel processing device according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a failure detection routine of the heating device according to the first embodiment.

FIG. 3 is a vertical cross-sectional view of an evaporated fuel processing device according to a second embodiment of the present invention.

FIG. 4 is a flowchart showing a failure detection routine of the heating device according to the second embodiment.

FIG. 5 is a vertical cross-sectional view of an evaporated fuel processing device according to a third embodiment of the present invention.

FIG. 6 is a flowchart showing a failure detection routine of the heating device according to the third embodiment.

FIG. 7 is a vertical cross-sectional view of an evaporated fuel processing device according to a fourth embodiment of the present invention.

FIG. 8 is a bridge circuit for detecting a failure of the heating device according to the fourth embodiment.

FIG. 9 is a graph for determining a failure of the heating device according to the fourth embodiment.

FIG. 10 is a flowchart showing a failure detection routine of the heating device according to the fourth embodiment.

[Explanation of symbols]

1 Evaporative fuel processor 2 canister 2a First adsorbent chamber 5 heater 9b Purge passage 10 A / F sensor 11 Evaporative fuel treatment equipment 15 Heater A 16 heater B 21 Evaporative fuel processor 25 heater 28 Temperature detecting means 31 Evaporative fuel treatment system

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shinsuke Kiyomiya             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. (72) Inventor ▲ Yoshi ▼ Mamoru Oka             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. F term (reference) 3G044 BA23 DA06 EA10 EA32 EA53                       EA55 EA57 FA10 FA11 FA12                       FA20 FA40 GA29

Claims (8)

[Claims] 1. An evaporative fuel processing apparatus including a heating device for temporarily adsorbing evaporated fuel generated in a fuel system and desorbing the evaporated fuel during engine operation to prevent leakage to the atmosphere. An evaporative fuel treatment system, characterized in that a failure of the heating system is judged based on a value detected by the abnormality detecting means. 2. The evaporated fuel processing apparatus according to claim 1, wherein the abnormality detecting means is a concentration detecting means. 3. A setting in which the concentration of the purged fuel is detected by the concentration detecting means immediately before the heating device is energized, and the purged fuel concentration is detected after the heating device is energized to set a difference between the two in advance. 3. The evaporative fuel treatment system according to claim 2, wherein the evaporative fuel treatment device is compared with a value, and if it is smaller than a set value, it is determined that the heating device has failed. 4. The evaporated fuel processing apparatus according to claim 1, wherein the abnormality detecting means is a current / voltage detecting means. 5. The current or voltage value detected by the current / voltage detecting means is compared with a preset value, and if the difference from the preset value is larger than a judgment value, the heating device is out of order. The evaporative fuel treatment system according to claim 4, wherein 6. The evaporated fuel processing apparatus according to claim 1, wherein the abnormality detecting means is a temperature detecting means. 7. If the output of the temperature detecting means does not change when the heating device is energized, it is determined that the heating device has failed, and even if there is an output change, an output change amount and a preset value are set. 7. The evaporative fuel treatment system according to claim 6, wherein when the difference between the two is larger than a determination value, it is determined that the function of the heating device has deteriorated. 8. An evaporative fuel processing apparatus provided with a heating device for temporarily adsorbing evaporative fuel generated in a fuel system and desorbing it during engine operation to prevent leakage to the atmosphere is disposed in the same adsorbent chamber of a canister. 2. The evaporated fuel according to claim 1, wherein the pair of heating elements are connected by a bridge circuit, and the failure and the functional deterioration of the heating device are determined based on the current value flowing in the bridge circuit. Processing equipment.