JPH0419341A - Aac valve malfunction diagnosis device - Google Patents

Abstract

PURPOSE:To enable simple and rapid malfunction diagnosis of an AAC valve based on deviation between an engine speed at the time of detecting a idling speed control signal value for fully closing and opening the AAC valve which bypasses a throttle valve, and an engine speed at the time of outputting an idling speed control signal in the reverse direction. CONSTITUTION:A malfunction diagnosis device 20 which are connected to an on-vehicle system 10 and which drivingly controls an actuator 13 such as an AAC valve based on outputs of sensors 12 is connected. It is detected whether an idle speed control signal value for controlling opening of an AAC valve which controls an auxiliary air quantity of an engine is that for outputting full close or open signal. In the case an idle speed control signal value for fully closing (opening) the AAC valve is detected, a reverse directional idle speed control signal for fully opening (closing) the AAC valve is outputted. The malfunction of the AAC valve is then detected based on the deviation between an engine speed in the case the idle rotational control signal value is detected, and an engine speed when the reverse control signal is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a failure diagnosis device for an AAC valve that controls the amount of auxiliary air in an engine.

(Prior Art) Conventionally, in an engine centralized electronic control system, various sensor signals (S,, S2°...Ss
) controls the opening degree of the throttle valve 3 provided at the inlet of the intake manifold 2 according to the control signal F of the ECC5 control unit 1 which is manually input, and the bypass passage 4 of the throttle valve 3 controls the amount of auxiliary air for the engine. AAC valve 5. Air regulator 6
, FICD solenoid valve 7 is provided.

Here, the AAC valve 5 controls the fluctuation of the idle speed due to the engine load, and in order to automatically adjust the engine speed to the pre-stored target engine speed,
The valve opening degree is adjusted based on the control signal F from the CC5 control unit 1.

(Problems to be Solved by the Invention) By the way, if the AAC valve as described above breaks down and becomes stuck in the open or closed state, normal idle speed control will not be performed. That is, if it is stuck in the open state, the engine will remain at high idle (the engine speed remains high), and if it is stuck in the closed state, the engine will idle unstable.

On the other hand, the causes of high idle failures include failures caused by the AAC valve not opening (hereinafter referred to as AAC valve open mode failures), as well as failures caused by the air regulator or FICD solenoid valve not opening. Possible causes include air suction from the intake piping system, and improper IAS (idle adjustment screw) adjustment.

In addition, causes of unstable idle include failures due to the AAC valve not closing as shown in ■- (hereinafter referred to as AAC valve closed mode failures), as well as failures due to the air regulator or FICD solenoid valve not closing. There may be a malfunction, a defect in the ignition system, etc.

Therefore, until now, when high idle failure or idle instability occurred, the AAC valve inspection method was as follows.
This was done by removing the AAC valve and visually checking whether the valve was fully open or not.

However, recent vehicles are focusing on design and aiming to improve aerodynamics, and the engine compartment has become smaller than before.

Therefore, the AAC valve cannot be removed as easily as before, and moreover, the AAC valve cannot be removed unless other parts are removed.

Furthermore, it is not uncommon for people to not know where the AAC valve itself is installed.

For this reason, the time required for inspection is increasing, and repair costs are also increasing.

This invention was made in view of the conventional problems such as "two legs", and its purpose is to simplify.

An object of the present invention is to provide an AAC valve failure diagnosis device capable of discovering failures of AAC valves at low cost.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides that the idle rotation speed control signal value that controls the opening degree of the AAC valve outputs a fully closed signal or a fully open signal. an idle rotation speed control signal value detection means for detecting whether the AAC valve is fully closed or fully open; , If an idle rotation speed control signal value that attempts to fully open the AAC valve is detected, an idle rotation speed control signal that attempts to fully open the AAC valve is output, and idle rotation speed control that attempts to fully open the AAC valve is performed. AAC valve reverse direction control signal output means for outputting an idle speed control signal to fully open the AAC valve when a signal value is detected; 10. Engine rotation speed detected by the engine rotation speed detection means when the reverse direction control signal is output; and engine rotation speed detected by the engine rotation speed detection means when the reverse direction control signal is output. AAC based on the difference between
The present invention is characterized by comprising a determination means for diagnosing a failure of the valve.

(Operation) In this invention, when the AAC valve has an open mode failure, the engine remains at high idle, so the AAC valve is controlled to reduce the air supplied from the AAC valve as much as possible (and lower the engine speed). Focusing on the fact that the idle speed control signal value outputs a fully open signal, the engine speed when the idle speed control signal value outputs a fully closed signal and the idle speed control signal value are forcibly set to fully open. The system detects the engine speed when the signal is changed to a signal, and if both engine speeds are below a predetermined value, it is determined that the AAC valve is malfunctioning in the open mode.

In addition, if the AAC pulp has a failure in the closed mode, the engine idle becomes unstable, so the idle speed control signal value outputs a fully open signal in order to increase the amount of air supplied from the AAC valve and reduce the rotation speed. We focused on detecting the engine speed when the idle speed control signal value outputs a fully open signal and the engine speed when the idle speed control signal value is forcibly changed to a fully closed signal. If the engine speed is below a predetermined value, it is determined that the AAC valve is in the closed mode and has failed. (Description of Examples) Hereinafter, the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the basic configuration of an embodiment to which the present invention is applied.

In the same figure, reference numeral 10 denotes a vehicle-mounted system, of which an engine control unit (ECM) 11 controls actuators such as AAC valves based on sensor outputs from various sensors 12 (water temperature sensor, idle switch sensor, neutral switch sensor, etc.). 13 is driven and controlled.

On the other hand, 20 is a fault diagnostic device connected to the ECMII on the vehicle side, l10 (input/output interface) 21, CPU
22. ROM23. It includes RAM24 and the like.

Further, numeral 30 denotes an input means constituted by a keyboard, a touch screen, etc., through which various information is manually entered into the fault diagnostic device 2o, or various information is inputted according to instructions from the diagnostic device 20.

Further, 40 is a display means such as a CRT, which displays the diagnosis results from the fault diagnostic device 20. Note that when the input means 30 is a touch screen or the like, it can also be used as the display means 40.

The following is an overall configuration diagram of the apparatus of this embodiment.

By the way, Fig. 2 shows the idle rotation speed control signal value (f) when the AAC valve is malfunctioning in the intake system, such as when the AAC valve is in the open mode, and Fig. 3 shows the idle rotation speed control signal value (f) when the AAC valve is normal and when the open mode is faulty. , (a) the idle speed control signal value (f) and (b) the engine speed (rpm) when the AAC valve is forcibly changed from the fully closed state to the fully open state are shown. Here, eye 1 supplied to the AAC valve
Focusing on the health rotation speed control signal value, when there is a failure in the intake system such as when the AAC valve open mode fails, it is controlled to a fully closed signal (fl) as shown in FIG.

On the other hand, if the AAC valve has an open mode failure and the fully open signal (f2) is sent after the fully closed signal (fl) is sent to the AAC valve, the engine speed will change as shown in Figure 3. As shown by the dotted line in (b), it does not increase from rpml.

This is because when the AAC valve is normal, when the idle speed control signal value f is changed from the fully closed signal f to the fully open signal f2, the engine speed increases by that amount, and from rpm to r
pm2 (solid line in Fig. 3(b)) or in the case of an open mode failure, this is because the engine speed does not increase because the AAC valve is stuck.

By the way, in this case, the AAC valve may not open due to an open mode failure, or the engine speed may fluctuate due to other factors. However, the difference in rotation speed due to this variation is smaller than that when the AAC valve is normal (rpm2-rpml).

Therefore, if the engine speed control signal value during operation after warming up the engine is below a predetermined reference value, for example, if a state is detected that sends a full open signal to the AAC valve, first engine speed rpm
Detect the engine speed rp when the idle speed control signal value is then forcibly changed from the fully closed signal to the fully open signal.
In this embodiment, m2 is detected, and if (rpm2-rpml) is less than a predetermined reference value, it is determined that the AAC valve has failed in the open mode.

Hereinafter, with reference to the flowchart of FIG. 4, the procedure for determining an AAC valve open mode failure, which is executed by the failure diagnostic device 20 in this case, will be described.

When a program is started by operating the keyboard of the human power means 30, first, "
The instruction "Please start the engine" is output, and the operator (serviceman, etc.) operates the ignition key of the vehicle to start the engine.

When the engine is started in this manner, it is first determined whether or not the engine is being warmed up based on the sensor outputs of the neutral switch sensor, idle switch sensor, and water temperature sensor (steps 100, 120, and 140).

At this point, the neutral switch is ON (step 10).
0 (YES), and the idle switch is ON (step 1).
20 (YES), the water temperature sensor value is at the predetermined standard value do
In the following cases (No in step 140), it is determined that the engine is warming up.

Meanwhile, the neutral switch and idle switch are ON.
If not, step 1 is displayed on the screen-1- of the display means 40.
10.Display message of 130.

Next, when it is determined that the water temperature has exceeded the reference value do and warm-up has been completed (YES at step 140), it is checked whether the idle rotation speed control signal value is outputting a fully closed signal (step 140). 150).

This is determined based on the duty ratio of the PWM signal sent from the ECMII to the AAC valve, and if the fully closed signal is not being output (NO in step 150), there is a problem other than the intake system (for example, the power steering switch It is determined that the high idle state has occurred due to an on-failure), and this fact is displayed on the screen of the display means 40, and the process is ended (step 160).

On the other hand, if the fully closed signal is being output (YES in step 150), detection of the engine rotation speed rpm is started, and the timer is initialized to t=0 (step 1
70).

Next, after a certain period of time has elapsed, the elapsed time t is 1. (YES at step 180), the diagnostic instrument 20 instructs the ECMII to fully open the AAC valve, and
11 outputs a fully open signal to the AAC valve (step 190).

In this way, when the full open signal to the AAC valve is output,
Next, it is checked whether a sufficient time t2 has elapsed for the AAC valve to be fully opened (step 200), and when t2 has elapsed (YES at step 200), the engine rotation speed detection processing is ended ( Step 210).

In this way, when a full open signal is output to the AAC valve ((1<t<t,), the engine rotational speed (rpm
) and when outputting a full open signal (t, <t
When an engine rotation speed (rpm2) of <t2) is detected, it is checked whether the value of (rpml-rpm2) exceeds a predetermined threshold de11 (step 220).

In this case, if the AAC valve is normal, the difference between r p m l and rpm2 will be a large value. On the other hand, if it is an open moto failure, the AAC valve is not open when rpml or rpm2 is detected, so there is almost no difference (actually, there may be a difference due to fluctuations in rotation speed, but the difference is small).

Therefore, by setting the threshold value dell to an engine speed range that clearly indicates that the AAC valve is normal,
If (r pm2 - r pm 1) exceeds dell (YES at step 220), it is assumed that there is a problem with the intake system other than the AAC valve, while (rpm2 - rpm)
is less than or equal to de11 (No at step 220), A
The AC valve is determined to be open failure (step 230)
.

In the above embodiment, the open mode failure of the AAC valve is determined by comparing the engine rotation speed rpm when the full open signal is output to the AAC valve with the engine rotation speed rpm2 when the full open signal is output. However,
After outputting the full open signal using the step controller 90, compare the engine rotation speed rpm at that time and the engine rotation speed rpm when the full open signal was output in real time.
It may be determined that the AAC valve open mode failure occurs when the cycle reaches 0 times. In this case, the determination process can be performed quickly.

In addition, another method of discrimination is before (Q<t<t,) and after (t+<t,) the full open signal is output to the AAC valve.
The AAC valve open mode failure may be determined by detecting the amount of change in the engine speed per unit time at < t 2 ), and determining whether or not this amount of change exceeds a predetermined threshold twice.

Furthermore, the above-described diagnostic method can be used not only with an off-board diagnostic device but also with an on-board diagnostic device.

As explained above, in this embodiment, when the AAC valve is in the open mode failure, the idle rotation speed control signal value that controls the AAC valve outputs a full open signal in order to reduce the amount of air supplied from the AAC valve as much as possible. Focusing on this, the idle speed control signal value when it is detected that the engine is running after warming up is a fully closed signal,
Moreover, the difference between the engine speed when the idle speed control signal value outputs a fully closed signal and the engine speed when the idle speed control signal value is forcibly changed to a fully open signal is a predetermined reference value. In the following cases, it is determined that the AAC valve has failed in open mode.

Therefore, service personnel can determine whether the AAC valve is open or not without removing the AAC valve, making it possible to diagnose AAC valve failures simply, quickly, and at low cost. Become.

Next, a method of diagnosing a case where the AAC valve is in a closed mode failure will be explained.

By the way, if the AAC valve is in the closed mode failure, an idle rotation speed control signal value that attempts to fully open the AAC valve is output even after complete warm-up.

Therefore, when it is detected that the idle speed control signal that attempts to fully open the AAC valve is output, the engine speed rpm3 (!:, then the AAC valve is forced to
Focusing on the engine speed rpm4 when the valve fully open idle speed control signal is output, (rpm3-rpm
4) exceeds a predetermined threshold (Jde12), AAC
In this embodiment, it is determined that the valve has failed in the closed mode.

Hereinafter, the above-mentioned determination processing procedure will be explained with reference to the flowchart of FIG.

Note that the processing from step 300 to step 340 in the figure is similar to the processing from step 100 to step 140 in FIG.

Therefore, redundant explanation will be omitted and the explanation of steps 300 to 340 will be omitted.

When it is detected that the warm-up has been completed through the processing up to step 340, it is then checked whether the idle rotation speed control signal value is outputting a fully open signal (step 35).
0).

This is the PW sent from the ECMII to the AAC valve.
It is determined based on the duty ratio of the M signal, and if the full open signal is not output (No in step 350), it is determined that the idle has become unstable due to a problem other than the intake system (for example, a failure in the ignition system). The display 40 indicates that
” screen” and terminates this process (step 360
).

On the other hand, if the full-open signal is being output (YES at step 350), detection of the engine rotational speed rpm is started, and the timer is set to the initial setting to t-0 (step 37n).

Next, when a certain period of time has elapsed and the elapsed time t exceeds t3 (YES at step 380), the diagnostic device 20 instructs the ECMll to fully open the AAC valve, and the ECMI
I outputs a full open signal to the AAC valve (step 390).

In this way, when the full open signal to the AAC valve is output,
Next, it is checked whether an elapsed time t4 sufficient to fully open the AAC valve has elapsed (step 400), and t
+ has passed (YES at step 400), the engine rotation speed detection process ends (step 410).
).

In this way, the engine rotation speed (rpm3) is when a fully open signal is output to the AAC valve (0 < t < t3) and when a fully closed signal is output (t 3 < t3).
t < t 4 ) engine rotation speed (rpm)
4) is detected, it is checked whether the value of (rpm3-rpm4) exceeds a predetermined threshold value de12 (step 420).

In this case, if the AAC valve is normal, r pm3 and rp
The difference in m4 is a large value. On the other hand, if it is a closed mode failure,
Since the AAC valve is always closed when rpm 3 is detected and when rpm 4 is detected, there is almost no difference.

Therefore, in this embodiment, the threshold de12 is set to AA
If the engine speed range is set to clearly indicate that the C valve is normal, and (rpm3-rpm4) exceeds de12 (YES at step 420), it is considered to be a malfunction in the intake system other than the AAC valve. rpm3-r
pm4) is less than or equal to de12 (No in step 420).
), the AAC valve is determined to be in a closed mode failure (step 430).

In addition, in this embodiment, the closed mode failure of the AAC valve is detected by comparing the engine rotation speed rpm 3 when the full open signal is output to the AAC valve and the engine rotation speed rpm 4 when the full open signal is output. However, after the fully closed signal is output in step 390, the engine speed rpm at that time is compared in real time with the engine speed rpm3 when the fully open signal is output, and when the value exceeds de12, the AAC valve is closed. It may be determined that this is a mode failure.

Also, before forcibly outputting a full open signal to the AAC valve (
The amount of change in engine speed per unit time between Q<t<t3) and after (13<1<1.) is detected, and the AAC valve close mode is activated depending on whether this amount of change exceeds a predetermined threshold. It may also be determined whether or not there is a failure.

Furthermore, the above-described diagnostic method can be used not only with an off-board diagnostic device but also with an on-board diagnostic device.

As explained above, in this embodiment, we focused on the fact that when the AAC valve has a failure in the closed mode, the idle rotation speed control signal value outputs a fully open signal in order to increase the amount of air supplied from the AAC valve. , the engine rotation speed when the idle rotation speed control signal value is a full open signal when it is detected that the engine is running after warming up, and the idle rotation speed control signal value outputs the full open signal. If the engine speed is below a predetermined reference value when the idle speed control signal value is forcibly changed to a full-open signal, the AAC
Since it is determined that the valve has failed in the closed mode, it is possible to determine whether or not the AAC valve has failed in the closed mode without having to remove the AAC valve as in the past. It will be possible.

(Effects of the Invention) The AAC valve failure diagnosis device according to the present invention detects the engine speed when an idle speed control signal value that fully closes or fully opens the AAC valve is detected as shown in the following. In addition, if an idle rotation speed control signal value that fully opens the AAC valve is detected, an idle rotation speed control signal that fully opens the AAC valve is detected, and an idle rotation speed control signal value that fully opens the AAC valve is detected. is AA
The system forcibly outputs an idle speed control signal that fully opens the C valve, detects the engine speed at the time of output, and diagnoses AAC valve failure based on the difference between the two engine speeds. , the service person is as usual.
The failure of the AAC valve can be determined without removing the AC valve, and the failure diagnosis of the AAC valve can be performed simply, quickly, and at low cost.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the overall configuration of an embodiment to which the present invention is applied, Fig. 2 is an explanatory diagram of the idle rotation speed control signal value when the intake system is defective, and Fig. 3 is a diagram showing the value of the idle rotation speed control signal when the AAC valve open mode fails. FIG. 4 is an explanatory diagram of the idle speed control signal value and the engine speed at that time when the AAC valve is changed from the fully closed state to the fully open state.
FIG. 5 is a flowchart showing the processing procedure of the second embodiment to which this invention is applied. FIG. 6 is a flowchart showing the processing procedure of the second embodiment to which the present invention is applied. FIG. 5...AAC valve 10...In-vehicle side system 11...ECM 12...Sensor 13...Actuator 20...Failure diagnostic device 30...Manual means 40...Display means

Claims (1)

[Claims] 1. Idle rotation speed control signal value detection means for detecting whether the idle rotation speed control signal value that controls the opening degree of the AAC valve outputs a fully closed signal or a fully open signal. and engine rotation speed detection means for detecting the engine rotation speed when an idle rotation speed control signal value that attempts to fully close or fully open the AAC valve is detected; If a control signal value is detected, an idle speed control signal is output to fully open the AAC valve, and if an idle speed control signal value is detected to fully open the AAC valve, the AAC valve is fully opened. an AAC valve reverse control signal output means for outputting an idle speed control signal to close the AAC valve; and an engine speed when outputting a reverse control signal for detecting the engine speed when a reverse control signal is output to the AAC valve. Detecting means, and diagnosing a failure of the AAC valve based on the difference between the engine speed detected by the engine speed detecting means and the engine speed detected by the engine speed detecting means when outputting the reverse direction control signal. 1. An AAC valve failure diagnosis device comprising: determination means.