JPH02130255A - Anomaly detecting device for fuel evaporation preventing device - Google Patents

Abstract

PURPOSE:To inform of the trouble of discharge of fuel gas into the atmosphere by detecting the feed anomaly of the fuel gas into a suction pipe due to the anomaly of at least one among a canister, suction passage, and a control valve, on the basis of the detected pressure between the control valve and the canister. CONSTITUTION:The adsorbing body M2 of a canister M3 adsorbs the fuel gas supplied from a fuel tank M1, and a control valve M6 opens and closes a feeding passage M5 according to the operation state of an internal combustion engine, and when the valve M6 is in opened state, the fuel gas adsorbed onto the adsorbing body M2 is introduced into a suction pipe M4 through the passage M5 by the negative pressure in the suction pipe M4. A pressure detecting means M7 detects the pressure between the canister M3 and the valve M6, and an anomaly detecting means M8 detects the anomaly of the supply of the fuel gas into the suction pipe M4 due to the anomaly at least in one among the canister M3, feeding passage M5, and the valve M6, on the basis of the pressure detected by the pressure detecting means M7. Therefore, the feed anomaly in which the fuel gas is not normally introduced into the suction pipe M4 is detected, and the trouble of the discharge of the fuel gas into the atmosphere is informed.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention detects an abnormality in the supply of fuel gas into an intake pipe in a fuel evaporation prevention device that prevents evaporation of fuel gas generated in the fuel supply system of an automobile. The present invention relates to an abnormality detection device for a fuel evaporation prevention device.

[Prior Art] Fuel evaporation prevention devices for preventing fuel gas generated in a fuel tank from being released into the atmosphere have been known. For example, as described in Japanese Patent Application Laid-Open No. 57-129247, there is a new system in which the fuel gas generated in the fuel tank is adsorbed by an adsorbent in the canister, and the negative pressure in the intake pipe is used to inhale it from the atmosphere opening hole in the canister. A device has been proposed that guides adsorbed fuel gas along with air into an intake pipe depending on the operating state.

[Problems to be Solved by the Invention] However, in these conventional devices, if the supply passage communicating with the intake pipe is crushed or clogged for some reason, the inside of the canister will not be filled with fuel gas. The tank becomes full, and eventually fuel gas is released from the hole opening to the atmosphere. Further, if the supply passage is damaged for some reason or the piping is disconnected and is exposed to the atmosphere, fuel gas will be released from the canister to the atmosphere. Furthermore, if the canister's atmosphere vent hole becomes clogged for some reason, the internal pressure of the canister will increase due to the fuel gas generated in the fuel tank, causing pipes to come off, and the fuel gas to be released in the same way. There is a problem in that fuel gas may be released into the atmosphere without being supplied into the intake pipe.

Therefore, the present invention aims to solve the above problem J,
An object of the present invention is to provide an abnormality detection device for a fuel evaporation prevention device that detects when fuel gas is not introduced into an intake pipe.

[Means for Solving the Problems] In order to achieve the above object, the present invention has the following configuration as a means for solving the problems. That is, as illustrated in FIG. 1, a canister M3 is provided with an adsorbent M2 that adsorbs fuel gas generated in a fuel tank Ml containing liquid fuel, and the fuel gas adsorbed on the adsorbent M2 of the canister M3. is provided in a supply passage M5 that leads into the intake pipe M4 by negative pressure generated in the intake pipe M4 of the internal combustion engine, and in the supply passage M5 that opens and closes the supply passage M5 according to the operating state of the internal combustion engine. a pressure detection means M7 for detecting the pressure between the canister M3 and the control valve M6; and a pressure detection means M7 for detecting the pressure between the canister M3, the supply passage M5, and the control valve M6 based on the detected pressure of the pressure detection means M7. This is a configuration of an abnormality detection device for a fuel evaporation prevention device characterized by comprising: abnormality detection means M8 for detecting an abnormality in the supply of the fuel gas to the intake pipe M4 due to at least one of the abnormalities.

[Function] The abnormality detection device for a fuel evaporation prevention device having the above configuration has the following features:
The adsorbent M2 of the canister M3 adsorbs fuel gas from the fuel tank M1, and the control valve M6 opens and closes the supply passage M5 depending on the operating state of the internal combustion engine, so that when the control valve M6 is open, , the supply passage M5 guides the fuel gas adsorbed by the adsorbent M2 to the intake pipe M4 due to the negative pressure in the intake pipe M4, and the pressure detection means M7 detects the pressure between the canister M3 and the control valve M6. , the abnormality detection means M8,
Based on the pressure detected by the pressure detection means M7, an abnormality in the supply of fuel gas to the intake pipe M4 due to an abnormality in at least one of the canister M3, the supply passage M5, and the control valve M6 is detected. Therefore, it is possible to detect a supply abnormality in which the fuel gas is not normally guided into the intake pipe M4, and to notify that the fuel gas will be released into the atmosphere.

[Example code] Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 2 is a schematic configuration diagram of an abnormality detection device for a fuel evaporation prevention device, which is an embodiment of the present invention. Air taken in through the air cleaner 1 that filters air is supplied to an intake v2 connected to the air cleaner 1. A throttle valve 8 that opens and closes in conjunction with an accelerator pedal 6 is provided within the intake pipe 2 . This intake pipe 2 is connected to the intake valve 1
0 to a combustion chamber 16 formed by the piston 12 and the internal combustion engine main body 14. Further, the combustion chamber 16 is connected to an exhaust pipe 20 via an exhaust valve 18.

On the other hand, a fuel pump 24 that pressurizes and supplies fuel in a fuel tank 22 containing liquid fuel is connected to a fuel injection valve 26 provided in the intake pipe 2, and controls opening and closing of the fuel injection valve 26. The structure is such that the fuel is injected. Further, the communication pipe 28 connected to the fuel tank 24 is connected to the canister 30, and inside the canister main body 32,
An adsorbent 34 for adsorbing fuel gas, for example activated carbon, is housed therein. Thereby, the adsorbent 34 included in the canister 30 is configured to adsorb the fuel gas generated in the fuel tank 22 via the communication pipe 2. The canister body 32 is formed with an atmosphere opening hole 36 that is open to the atmosphere, so that air can be sucked into the canister body 32 .

Further, one end of the supply pipe 3 is inserted into the hose connection portion 32a of the canister main body 32 and connected to the canister 30, and the other end of the supply pipe 3 is connected to the control valve 40. One end of a supply pipe 42 is connected to the control valve 40, and the other end of this supply pipe 42 is connected to the intake pipe 2, with the control valve 40 interposed between both supply pipes 38 and 42. The intake pipe 2 and the canister 30 can communicate with each other via the control valve 40 and the supply pipe 42. The control valve 40, in response to a human signal, connects both supply pipes 38, 42
It has a structure that communicates and blocks communication.

A supply passage M5 is constituted by both supply pipes 38.42, and the supply pipes 38.42 are generally made of a flexible material such as a rubber hose or a nylon hose.

A pressure sensor 44 serving as pressure detection means M7 for detecting the pressure between the canister 30 and the control valve 40 is disposed in the canister main body 32. Note that the pressure sensor 44 can also be installed on the third day of the supply pipe.

These fuel injection valve 26, control valve 40, pressure sensor 44
are each connected to an electronic control circuit 50. The electronic control circuit 50 includes a well-known CPtJ 52, an R 0M 54 that stores control programs and data in advance, a readable/writable RAM 56, and an input/output circuit 58 interconnected via a common bus 60. The CPU 52 inputs signals from the pressure sensor 44 via the input/output circuit 58, and based on these signals, programs and data in the ROM 54, RAM 56, etc., the CPU 52 controls the fuel injection valve via the input/output circuit 58. 26, output a drive signal to the control valve 40;

Next, the processing performed by the electronic control circuit 50 described above will be explained with reference to the flowchart shown in FIG.

When a key switch (not shown) is turned on, the present abnormality detection device for a fuel evaporation prevention device repeatedly executes the abnormality detection process shown in FIG. 3 at predetermined time intervals along with the fuel injection control process.

First, the operation of preventing fuel evaporation will be explained. Fuel gas evaporated from the fuel in the fuel tank 22 passes through the communication pipe 28 and is adsorbed by the adsorbent 34 in the canister 30 . This adsorbed fuel scum can be introduced into the intake pipe 2, for example, when the throttle valve 8 is opened to a predetermined opening degree or more and the throttle valve 8 is not idling, a signal is manually input to the control valve 40. The valve is controlled to be closed. When the control valve 40 is opened, the fuel gas adsorbed by the adsorbent 34 is absorbed into the supply pipe 3 by the negative pressure in the intake pipe 2.
The fresh air is supplied into the intake pipe 2 through the control valve 40 and the supply pipe 42 together with fresh air taken in from the atmosphere opening hole 36 . This allows the adsorbent 34 to be used repeatedly. The fuel gas supplied into the intake pipe 2 is subjected to combustion in the combustion chamber 16 together with the fuel injected from the fuel injection valve 26.

In this way, the control valve 40 is controlled to open and close depending on the operating state of the internal combustion engine, and at the same time, this abnormality detection process is repeatedly executed at predetermined time intervals.

First, the data detected by the pressure sensor 47N and stored in the current pressure memory Pn of the RAM 56 are transferred to the previous pressure memory P by the previous execution of this abnormality detection process. -1 (
Step 100). Next, by executing this abnormality detection process, the pressure data P detected by the pressure sensor 44 is stored in the current pressure memory Pn (step 1
10). That is, the previous pressure value is the previous pressure memory P. -1
The current pressure values are stored in the current pressure memories P, , respectively.

Next, this time pressure memory P. It is determined whether the pressure data stored in is greater than a predetermined value (step 120). This predetermined value is, for example, determined in advance through experiments or the like, and is determined when the atmospheric release hole 3G of the canister 30 is closed and the control valve 40 is in the closed state.
The pressure is set to a value near the maximum pressure between the canister 22 and the supply pipe 3 days, for example, a value slightly larger than atmospheric pressure.

If the data in the current pressure memory P0 is determined to be larger than the predetermined value ff1K through the processing in step 120, it is assumed that an abnormality has occurred, and abnormality setting is executed (step 1
60). In this abnormality setting, for example, it is stored in the RAM 56 that an abnormality has occurred, and a display lamp is turned on to notify that an abnormality has occurred. That is, the current pressure memory P. If the data is larger than the predetermined value [K, the canister 30
For some reason, the atmosphere opening hole 36 is clogged with something, or the atmosphere opening hole 36 is crushed and blocked, and the fuel gas generated in the fuel tank 22 is transferred to the communication pipe 2. The pressure inside the canister 30 is increasing due to the fuel gas flowing into the canister 30 over the course of the day.

When the pressure inside the canister 30 increases, the canister 30
The control valve 40 and the supply pipe 38 may become disconnected, or the control valve 40 and the supply pipe 38 may become disconnected, and it is determined that an abnormality has occurred.

On the other hand, as a result of the process in step 120, the current pressure memory P
If it is determined that the data of n is less than or equal to a predetermined value, it is determined whether the state of the control valve 40 has changed between the previous execution of the main abnormality detection process and the current execution of the main abnormality detection process. It is determined whether or not (step 130). That is, during the previous process, the control valve 40 was in the open state, and during the current process, it was in the closed state, and the state has been switched, or the control valve 40 was in the closed state during the previous process, or In this case, the control valve 40 is in the closed state, and in the current process, it is in the open state,
Determine whether the state has changed. When the state has changed, the data in the previous pressure memory Pn-+ is subtracted from the data in the current pressure memory Pn, and the result is stored in the pressure difference ΔP (step 140).

Next, it is determined whether the absolute value of this pressure difference Δl) is smaller than a predetermined value (step 150).

This predetermined value is a value determined in advance through experiments or the like, and is a value near the minimum value of the normal pressure fluctuation range between the canister 30 and the control valve 40. That is, before and after the control valve 40 is switched, when the control valve 40 is in the open state, the pressure between the supply pipe 38 and the canister 30 is low due to the negative pressure in the intake pipe 2; , when the control valve 40 is in the closed state, the supply pipe 3 and the canister 30
The pressure between is approximately equal to atmospheric pressure. Therefore, if the pressure difference P before and after switching of the control valve 40 is normal, it will be larger than the predetermined value.

However, if the supply pipes 38 and 42 are crushed or bent for some reason, or if something is clogged and they become blocked, or if the control valve 40 malfunctions and remains closed. , the pressure between the control valve 40 and the canister 30 remains approximately equal to atmospheric pressure, and the pressure difference ΔP
is approximately 0 and does not change. Furthermore, the connection between the supply pipe 38 and the canister 30 was disconnected, and the supply pipe 38. 4
2 and the control valve 40 are disconnected, or when the supply pipe 42 and the intake pipe 2 are disconnected,
Similarly, the pressure between the control valve 40 and the canister 30 does not vary and remains approximately equal to atmospheric pressure, and the pressure difference ΔP is approximately zero.

Therefore, when the absolute value of P to the pressure difference is smaller than a predetermined value, it is determined that an abnormality has occurred, and, for example, the RAM
56 and executes an abnormality setting to turn on the display lamp (step 160).

In addition, after it is determined that the switching has been completed by the process of the stem 130, a process is added to determine whether or not the data in the pressure memory P is at about atmospheric pressure. .48 blockage or a failure of the control valve 40, which may cause an abnormality in which the valve remains closed.

On the other hand, in the process of step 150, if the absolute value of the pressure difference P is equal to or greater than the predetermined value, it is determined that the fuel evaporation prevention device is normal, and after executing the normal setting (step 1
70) - Once the abnormality detection and determination process is exited. or,
- After the abnormality is determined by the processing in steps 150 and 160, this abnormality detection processing is repeatedly executed, and the absolute value of the pressure difference ΔP is determined to be greater than or equal to a predetermined value by the processing in step 150. Then, through the process of step 170, for example, the contents stored in the RAM 56 indicating the abnormality are reset, and the indicator lamp indicating the abnormality is turned off. That is, for example, it is determined that the supply pipes 38, 42, which were bent and blocked, have been corrected and returned to a normal state, and the display of the abnormal state is reset.

Further, if it is determined that the control valve 40 is not switched by the process of step 130, or if it is determined that the control valve 40 is not switched,
When the process 60 is executed, the process exits from the abnormality detection process.

Note that execution of the abnormality detection process functions as abnormality detection means M8. In this embodiment, all abnormalities in the canister 30, the control valve 40, and the supply pipes 38 and 42 are detected.
A configuration may be adopted in which only an abnormality in the canister 30 is detected by executing the processes from 0 to 120.160. In addition, by performing the processes of steps 100, 110, and 130 to 170, the supply pipe is used for 3 days.

42 or the control valve 40 is also possible.

Furthermore, in this embodiment, the fuel supply system using the fuel injection valve 26 has been described, but in the case of a carburetor type fuel supply system, not only the fuel gas generated from the fuel tank 22 but also the fuel gas generated in the float chamber. Canister fuel gas 3
It is also possible to implement a configuration in which the liquid is adsorbed to the adsorbent 34 of 0.0.

As mentioned above, the abnormality detection device for the fuel evaporation prevention device has the following features:
The adsorbent 34 of the canister 30 adsorbs the fuel gas from the fuel tank 22, and due to the negative pressure in the intake pipe 2, the supply pipe 3 guides the fuel gas adsorbed by the adsorbent 34 to the intake pipe 2, increasing the pressure. The sensor 44 detects the pressure between the canister 30 and the control valve 40, and the pressure P detected by the pressure sensor 44 is
Based on this, it is determined whether the atmospheric vent hole 36 of the canister 30 is closed or not (step 120), and the pressure difference between the pressure P before and after the switching of the open/closed state of the control valve 40 detected by the pressure sensor 44 is determined. Based on P, supply pipe 3B
, 42. Determine an abnormality in the control lI valve 40 to detect an abnormality in the supply of fuel gas to the intake pipe 2.

Therefore, based on the pressure detected by the pressure sensor 44, an abnormality in which fuel gas is not supplied into the intake pipe 2 is detected, and it is detected that the fuel gas is released into the atmosphere. That is, the atmosphere opening hole 36 of the canister 300 becomes clogged, the supply pipe 38 comes off, and the fuel gas is released to the atmosphere, or the supply pipe 38.
42 is blocked or the control valve 40 is malfunctioning and remains closed, cutting off the communication between the canister 30 and the intake pipe 2 and detecting that fuel gas is released from the atmosphere release hole 36. do. Furthermore, it is detected that the supply pipes 38, 42, the canister 30, and the control valve 42 are disconnected and the fuel gas is released from there into the atmosphere.

As described above, the present invention is not equally limited to these embodiments, and may be implemented in various forms without departing from the gist of the present invention.

[Effects of the Invention] As described in detail above, the fuel evaporation prevention device of the present invention detects the occurrence of malfunction of the control valve, blockage of the supply passage, disconnection, etc. based on the detected pressure between the control valve and the canister. This has the effect of detecting an abnormality in which fuel gas is not supplied into the intake pipe and detecting that fuel gas is being released into the atmosphere.

FIG. 1 is a block diagram illustrating the basic configuration of the present invention, FIG. 2 is a schematic configuration diagram of an abnormality detection device for a fuel evaporation prevention device as an embodiment of the present invention, and FIG. 3 is a block diagram illustrating the basic configuration of the present invention. 3 is a flowchart illustrating an example of control processing performed in a control circuit.

Ml, 22...Fuel tank M3.30...Canister M5...supply passage Ml...Pressure detection means 8... Throttle valve 38.42... Supply pipe 44...pressure sensor

Claims (1)

[Claims] A canister including an adsorbent for adsorbing fuel gas generated in a fuel tank containing liquid fuel, and a canister for generating fuel gas adsorbed by the adsorbent of the canister in an intake pipe of an internal combustion engine. a supply passage that is guided into the intake pipe by negative pressure; a control valve provided in the supply passage that opens and closes the supply passage depending on the operating state of the internal combustion engine; and a control valve between the canister and the control valve. pressure detection means for detecting pressure; and abnormality detection means for detecting an abnormality in the supply of the fuel gas to the intake pipe due to an abnormality in at least one of the canister, the supply passage, and the control valve based on the pressure detected by the pressure detection means. An abnormality detection device for a fuel evaporation prevention device, comprising: