JPH02102360A - Diagnostic device for processing means for fuel evaporated gas - Google Patents

Abstract

PURPOSE:To prevent fuel evaporated gas from being released by detecting abnormalities in a fuel evaporated gas processing means including a canister based on the result of comparison between pressure within a tank and reference pressure, and thereby providing a warning to an operator so that necessary actions shall be taken. CONSTITUTION:A fuel evaporated gas processing means is equipped with a canister B which houses absorbents absorbing fuel evaporated gas generated within a fuel tank A storing fuel to be fed to an engine, and with a gas induction pipe C provided between the canister B and a suction pipe in order to lead fuel evaporated gas absorbed by the absorbents in the canister B into the suction pipe. In this case, a pressure detecting means D detecting pressure within the fuel tank A is provided so that pressure within the tank detected by the pressure detecting means D is compared with a specified reference pressure by a comparison means E. And when pressure within the tank is judged to have been higher than the reference one, it is judged that abnormalities have been occurred in the fuel evaporated gas processing means, a warning means F is thereby actuated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a diagnostic device for a fuel evaporative gas processing means provided for a vehicle engine.

[Conventional technology]

Conventionally, in order to prevent the fuel evaporative gas generated in the fuel tank from escaping into the atmosphere, a canister is provided to adsorb the fuel evaporative gas, and the fuel evaporative gas adsorbed in this canister is introduced into the gas. BACKGROUND OF THE INVENTION A fuel vapor treatment system is known in which fuel is guided into the intake pipe of an engine via a pipe depending on the engine condition. (Tokuko Showa 63-3
(Refer to Publication No. 9787) [Problems to be Solved by the Invention] By the way, fuel evaporation that occurs in the fuel tank due to clogging of a passage between the fuel tank and the canister for guiding evaporative fuel gas in the fuel tank to the canister. When gas cannot be guided to the canister side, the pressure inside the fuel tank becomes high, and fuel evaporative gas begins to leak into the atmosphere from the fuel supply port of the fuel tank. Even if fuel evaporative gas leaks in this way, the driver does not notice any abnormality at all because it does not affect the drivability of the vehicle. However, since the abnormality is not notified at all, there is a problem in that fuel evaporative gas continues to be emitted.

Therefore, an object of the present invention is to detect an abnormality in the fuel evaporative gas treatment means and provide a warning to the driver to take appropriate measures.
It is an object of the present invention to provide a diagnostic device for a fuel evaporative gas processing means that can suppress the release of fuel evaporative gas as much as possible.

[Means to solve the problem]

In order to solve the above-mentioned problems and achieve the above-mentioned objects, in the present invention, as shown in FIG. A fuel evaporative gas treatment means comprising a canister to accommodate the canister and a gas introduction pipe provided between the canister and the intake pipe for guiding the fuel evaporative gas adsorbed by the adsorbent of the canister into the intake pipe. a pressure detection means for detecting the pressure within the fuel tank; a comparison means for comparing the pressure within the tank detected by the pressure detection means with a predetermined reference pressure; A diagnostic device for a fuel evaporative gas processing means, comprising: an alarm means for determining that an abnormality has occurred in the fuel evaporative gas processing means and issuing an alarm when it is determined that the pressure inside the tank is higher than the internal pressure of the fuel evaporative gas processing means. There is.

[Effect]

According to the above configuration, the pressure in the fuel tank is compared with the reference pressure, and an alarm is issued for abnormality in the fuel evaporative gas processing means in accordance with the comparison result.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

In FIG. 1, reference numeral 1 denotes a spark ignition four-cylinder gasoline engine, which is mounted on a vehicle.

This engine 1 is provided with a spark plug 3. Further, an intake pipe 5 and an exhaust pipe 7 are connected to the engine l.

An air cleaner 9 is provided at the upstream end of the collecting pipe portion 51 of the intake pipe 5, and an air flow meter 11. An intake air temperature sensor 131 for detecting the intake air temperature, a throttle valve 15 for adjusting the intake air amount in conjunction with an accelerator pedal (not shown), and an idle switch for detecting that the throttle valve 15 is in the fully closed position. It is equipped.

The surge tank section 53 is provided between the collecting pipe section 51 and branch pipe sections 55 that are branched corresponding to each cylinder. In addition, each branch pipe section 55 has an electromagnetic fuel injection valve (injector).
19 are provided.

The exhaust pipe 7 is provided with an 02 sensor 21 for detecting the residual oxygen concentration in the exhaust gas and detecting the air-fuel ratio of the air-fuel mixture supplied to the engine.

Further, the engine 1 is provided with a water temperature sensor 23 for detecting the temperature of engine cooling water and a rotation speed sensor 25 for detecting the rotation speed of the engine 1.

The fuel tank 30 has an injector 19 which injects the fuel in the tank.
A pump 32 is provided for supplying the water. In addition,
As is well known, the pressure of the fuel supplied to the injector 19 is regulated by a pressure regulating valve (not shown).

The fuel evaporative gas generated in the fuel tank is led to a canister 40 via a pipe 33 and a check valve 34, and the canister 40 contains activated carbon 42 that adsorbs the evaporative gas. Further, a gas introduction pipe 44 for introducing the evaporated gas adsorbed on the activated carbon 42 of the canister 40 to the downstream side of the throttle valve 15 in the collecting pipe section 51 of the intake pipe 5 is provided between the canister 40 and the collecting pipe 51. A solenoid valve 46 is provided in the middle of the introduction pipe 44 to open and close the pipe.

By the way, the fuel tank 30 is equipped with a pressure sensor 35 for detecting the pressure inside the tank. An in-tank temperature sensor 36 for detecting the temperature inside the tank, and a fuel switch 3 for detecting that new fuel is supplied into the tank.
7 is provided.

Note that the fuel switch 37 may be a switch that detects that the lid of the fuel tank 30 is opened, a switch that detects that a nozzle for supplying new fuel into the tank is inserted, or the like. Furthermore, instead of using the fuel switch 37, if a device that measures the amount of fuel in the tank (for example, a liquid level sensor) detects a sudden increase in fuel, it may be determined that new fuel is being supplied.

The electronic control circuit (ECU) 100 is on even if the engine is not running as long as a switch (not shown) is closed, and receives signals from the above-mentioned sensors and switches, and controls the injector based on the input signals. 19 and the solenoid valve 46, and also outputs a drive signal to the pipe 33. The canister 40 is connected to the gas introduction pipe 44. A signal is output to a warning lamp 60 that is turned on according to the diagnosis result of the diagnosis process of the fuel evaporative gas processing means constituted by the electromagnetic valve 46 and the like.

Note that the warning lamp 60 is provided in a position visible to the driver inside the vehicle, and is provided, for example, in an instrument panel provided with a speedometer or the like that displays the vehicle speed.

By the way, ECUloo has air flow meter 11 as is well known.
The basic injection amount Tp is determined based on the signal from the rotation speed sensor 25 and the signal from the rotation speed sensor 25, and this Tp is determined from the water temperature sensor 25.
3 and the correction value according to the signal from the intake temperature sensor 13, and when the engine 1 is not in idle operation and is not in transient operation (during acceleration or deceleration), the signal is adjusted to 0□sense signal. Accordingly, the air-fuel ratio of the air-fuel mixture supplied to the engine 1 is corrected with a correction value determined to match the stoichiometric air-fuel ratio, the fuel injection amount is determined, and a signal corresponding to this determined injection amount is sent to the injector 19. Output for.

Furthermore, the ECtJ 100 controls the solenoid valve 46 to close the introduction pipe 44 when the idle switch 17 is ON and the fully closed throttle valve 15 is detected.
Conversely, when the idle switch 17 is OFF and it is detected that the throttle valve 15 is open, a drive signal is output to open the introduction pipe 44.

Furthermore, the ECUloo executes a program shown in the flowchart of FIG. 2 to diagnose the fuel evaporative gas processing means. Note that this process is executed, for example, every second.

First, in step 201, it is determined whether the fuel switch 37 is ON, that is, whether new fuel is being supplied. If the fuel switch 37 is ON, the process proceeds to step 202, where the new fuel is supplied. The timer TR indicating the time is initialized and the process ends. If the fuel switch 37 is OFF, a correction coefficient KR is determined in step 203 based on the timer TR. Note that this correction coefficient KR is stored in advance as a map in a memory provided in the ECU according to the timer TR, and is set as shown in FIG. 3, for example.

Next, in step 204, a correction coefficient KF is determined in accordance with the fuel tank internal temperature TF detected by the signal from the tank internal temperature sensor 36. This correction coefficient KF is also stored in advance as a map in the memory in the ECU according to the temperature TF.
For example, the settings are as shown in FIG.

Next, in step 205, the base value PO is adjusted by a correction coefficient KR,
A reference pressure P1 is determined by correcting with KF.

Next, in step 206, it is determined whether the idle switch 17 is ON, that is, whether the throttle valve 15 is fully open. If it is ON, the reference pressure P1 is determined in step 207.
further idle correction.

This is to correct the reference pressure P1 depending on whether or not the evaporated gas in the canister 40 is guided into the intake pipe 5 via the gas introduction pipe 44. If the evaporated gas is not introduced into the intake pipe 5, the reference pressure PL is adjusted. is increasing.

In the following step 208, the reference pressure P determined in the above process is
1 and the tank internal pressure PT detected by the signal of the pressure sensor 35, and if PT>P1, there is some abnormality in the fuel evaporative gas processing means (for example, a blockage in the pipe 33, atmospheric pressure in the canister 40, etc.). It is determined that the opening port 48 is clogged, the introduction pipe 44 is clogged, etc.), and an output is sent to the warning lamp 60 to turn on the warning lamp 60 in step 209.

According to the above process, when an abnormal pressure state in the fuel tank 30, that is, a high pressure state exceeding the reference pressure, is detected, it is determined that there is an abnormality in the fuel evaporative gas processing means, and the abnormality is notified to the driver. It is possible to prompt the driver to repair the processing means.

Therefore, if the driver does not notice the abnormality and leaves it unattended,
Continuous release of fuel evaporative gas from inside the tank can be sufficiently suppressed.

Furthermore, in the above process, the reference pressure is determined based on various types of information, so it is possible to reliably prevent erroneous determination that there is an abnormality.

By the way, in the above embodiment, the temperature inside the fuel tank is directly detected, but it may be estimated from the intake air temperature or the like. That is, the base value PO may be corrected by determining a correction coefficient corresponding to the intake air temperature detected by the air intake air temperature sensor 13.

Further, when the amount of fuel is greater than a predetermined amount, the reference pressure may be corrected to a higher value.

Furthermore, if the electromagnetic valve 46 is opened only when the amount of fuel injected from the injector 19 is feedback-controlled as described above using the 0□sen signal, the reference pressure P1 is modified in accordance with that state. It's better to let them.

Furthermore, if the electromagnetic valve 46 is not a simple on-off valve but one whose opening degree is controlled continuously or in multiple stages by duty control etc., the reference pressure P1 should be corrected according to the opening degree. You can also do this.

Furthermore, although the above-mentioned embodiment shows the system used in a fuel injection type system, it goes without saying that a system using a carburetor may also be used.

Furthermore, as a warning means, in addition to a visual means such as the above-mentioned warning lamp 60, an auditory means such as a buzzer may be used.

〔Effect of the invention〕

As described above, according to the present invention, an abnormality in the fuel evaporative gas processing means is detected based on the pressure inside the tank, and an alarm is issued to the driver to urge repair. This has an excellent effect in that it can sufficiently suppress the situation where fuel evaporative gas continues to be emitted due to being left completely unnoticed.

1...Engine, 5...Intake pipe, 30...Fuel tank.

Claims (5)

[Claims] (1) A canister containing an adsorbent that adsorbs evaporative fuel gas generated in a fuel tank storing fuel to be supplied to the engine, and guiding the evaporative fuel gas adsorbed by the adsorbent of the canister into the intake pipe. For this purpose, a fuel evaporative gas treatment means including a gas introduction pipe provided between the canister and the intake pipe; a pressure detection means for detecting the pressure within the fuel tank; and a pressure detection means for detecting the pressure within the fuel tank; a comparison means for comparing the tank internal pressure with a predetermined reference pressure; and when the comparison means determines that the tank internal pressure is greater than the reference pressure, an abnormality occurs in the fuel evaporative gas processing means. 1. A diagnostic device for a fuel evaporative gas processing means, comprising: an alarm means for determining that the fuel has evaporated, and issuing an alarm. (2) The apparatus according to claim (1), further comprising: temperature detection means for detecting the temperature within the fuel tank; and reference pressure setting means for setting the reference pressure according to the temperature within the tank. A diagnostic device for a fuel evaporative gas processing means, characterized by: (3) The device according to claim (1), further comprising: intake temperature detection means for detecting intake temperature; and reference pressure setting means for setting the reference pressure in accordance with the intake temperature. Diagnostic device for evaporative gas treatment means. (4) The apparatus according to any one of claims (1) to (3), further comprising a detection means for detecting that new fuel has been supplied into the fuel tank, and supply of new fuel by the detection means. A diagnostic device for a fuel evaporative gas processing means, comprising: a reference pressure correction means for correcting the reference pressure according to the elapsed time from the time when the evaporative gas processing means is detected. (5) In the device according to any one of claims (1) to (4), the fuel evaporative gas is further introduced into the intake pipe from the gas introduction path of the fuel evaporative gas processing means. an introduction state determining means for determining whether the introduction of fuel evaporative gas is being carried out; A diagnostic device for a fuel evaporative gas processing means, comprising: a reference pressure changing means for changing the reference pressure to a larger value than the reference pressure.