JPH0344214B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for determining an output disconnection failure of a throttle sensor that detects the opening degree of a throttle valve disposed in an engine intake passage. In particular, the present invention relates to a throttle sensor failure determination device suitable for use in a device for controlling the idle operating state of an engine and a failure display device for a throttle sensor.

[Conventional technology]

Conventionally, this type of engine idle control device detects the engine speed, throttle valve opening, vehicle speed, etc., and performs feedback control of the engine speed (speed control) under certain conditions during idling. There has been proposed a system in which position feedback control of the throttle valve can be performed under other conditions during idling operation.

Here, the above conditions refer to a case where at least the following items are satisfied, and refer to a condition in which the engine is relatively stable.

(1) A predetermined amount of time has elapsed after the idle switch was turned from off to on.

(2) The vehicle speed is extremely low (for example, 2.5 km/h or less), that is, the signal frequency from the vehicle speed sensor, which detects vehicle speed with a pulse signal having a frequency proportional to the vehicle speed, is below a predetermined value.

(3) The deviation of the actual engine speed (actual speed) from the target speed must be within a specified range.

(4) In vehicles equipped with a cooler, after the cooler relay etc. switches according to the cooler load,
The specified time has elapsed.

Further, the above conditions refer to conditions when the above conditions are not satisfied, the engine is relatively unstable, and rapid feedback control is desired.

[Problem that the invention seeks to solve]

However, with conventional engine idle control devices, if the throttle sensor (usually composed of a potentiometer) that detects the opening of the throttle valve is disconnected (including a disconnection of the output cord), The voltage input to the computer becomes a voltage equivalent to a fully open throttle, but with conventional means, the voltage equivalent to a fully open throttle may be reduced due to a disconnection of the output of the throttle sensor, or when the accelerator pedal is depressed. Since it is not possible to determine whether the throttle valve is fully open, the computer determines from the voltage equivalent to the fully open throttle and controls the throttle valve to close.This causes the throttle valve opening to become even smaller, causing a so-called engine stall. There is a problem with this.

In addition, if you want to calibrate the throttle opening using the output from the airflow sensor during idle speed control in consideration of the installation error of the throttle sensor, and then perform learning control for this calibration, as described above. Due to a disconnection of the throttle sensor, the throttle opening learning value during learning control becomes abnormally large.

As a result, even after the throttle sensor is properly repaired, the above-mentioned learned value is reflected and the engine speed during idling becomes abnormally high.

The present invention aims to solve these problems, and is designed to reliably confirm that the throttle sensor is malfunctioning when the throttle sensor has an output disconnection failure and outputs a detection signal equivalent to a fully open throttle. It is an object of the present invention to provide a throttle sensor failure determination device that can perform determination.

[Means for solving problems]

Therefore, the throttle sensor failure determination device of the present invention is equipped with a throttle sensor that detects the opening degree of the throttle valve provided in the intake passage of the engine. An air flow sensor that detects the amount of intake air in the intake passage and a rotation speed sensor that detects the engine speed are provided, and the value detected by the throttle sensor corresponds to a throttle valve opening that is larger than the idle opening. is larger than the predetermined value, the value (A/N) obtained by dividing the intake air amount information detected by the air flow sensor by the engine rotation speed information detected by the rotation speed sensor is the predetermined value. If the A/N value is smaller than the second predetermined value regarding the A/N corresponding to the opening degree of the throttle valve which is smaller than the opening degree of the throttle valve corresponding to the throttle valve opening degree, it is determined that the throttle sensor is in an output disconnection failure state. The present invention is characterized in that it is provided with a failure determination means that outputs a signal to that effect.

[Effect]

With this configuration, if the throttle sensor has an output disconnection failure, the detected value from the throttle sensor will be the value equivalent to the throttle being fully opened, but the value obtained by dividing the intake air amount information by the engine rotation speed information ( This value also has throttle opening information) is related to the A/N corresponding to the throttle valve opening smaller than the predetermined value corresponding to the throttle valve opening larger than the idle opening. If it is smaller than the second predetermined value, it is determined that such a phenomenon is not due to the depression of the accelerator pedal but to a malfunction of the throttle sensor, and a signal indicating that the throttle sensor is malfunctioning is output. It is.

〔Example〕

Hereinafter, a throttle sensor failure determination device as an embodiment of the present invention will be explained with reference to the drawings. Figures 1 to 12 show an engine idle control device having this device, and Figure 1 shows the throttle sensor failure determination device. Figure 2 is a flowchart showing the main points of judgment, Figure 2 is its overall configuration diagram, Figure 3 is its main part configuration diagram, Figures 4 to 7 are graphs to explain each action, and Figures 8 to 12 are their respective diagrams. It is a flow chart for explaining the action.

As shown in FIG. 2, an internal combustion engine E such as a gasoline engine for use in an automobile according to this embodiment
(hereinafter simply referred to as "Engine E") is equipped with a turbocharger 3. The turbocharger 3 includes a turbine 4 interposed in the exhaust passage 2 of the engine E, and a compressor 5 interposed in the intake passage 1 of the engine E and rotationally driven by the turbine 4.

Note that a bypass passage that detours around the turbine installation portion of the exhaust passage 2 is connected to the exhaust passage 2,
A waste gate valve 6 is provided to open and close this bypass passage. This waste gate valve 6 is designed to be opened and closed by two diaphragm pressure-responsive devices 7, and an electromagnetic switching valve 34 (this valve 34 has a return spring (not shown) for the valve body). By selectively supplying atmospheric pressure and supercharging pressure to one pressure chamber of the pressure response device 7, the opening timing of the waste gate valve 6, etc. is adjusted, and at least two types of supercharging pressure characteristics are realized. I'm starting to be able to do it.

In addition, in the intake passage 1 of the engine E, in order from the upstream side (air cleaner side), an air flow sensor 16, a compressor 5 of the turbocharger 3,
An intercooler 8, electromagnetic fuel injection valves 9 and 10 (these valves 9 and 10 have different injection capacities), and a throttle valve 11 are provided in the exhaust passage 2 of the engine E on the upstream side (engine combustion chamber side) A turbine 4 of the turbocharger 3, a catalytic converter 31, and a muffler (not shown) are provided in this order.

As shown in Fig. 3, intake passage 1 of engine E
A shaft 11a of a throttle valve 11 disposed in the intake passage 1 is connected to a throttle lever 11c outside the intake passage 1.

Further, when an accelerator pedal (not shown) is depressed, the end portion 11d of the throttle lever 11c
Throttle valve 1 via throttle lever 11c
A wire (not shown) is connected to the throttle valve 11 to rotate the throttle valve 11 in the clockwise direction (opening direction) in FIG. 1) is installed, so that when the tensile force of the wire is weakened, the throttle valve 11 closes.

By the way, an actuator 12 is provided that controls the opening degree of the throttle valve 11 during engine idling operation, and this actuator 12 is equipped with a DC motor (hereinafter simply referred to as "motor") 13 having a worm 14a on its rotating shaft. hand,
The worm 14a with the motor 13 meshes with an annular worm wheel 14b.

This worm wheel 14b has a female threaded portion 14.
A pipe shaft 14c having a diameter b is integrally provided, and a rod 15 having a male threaded portion 15a screwed into the female threaded portion 14d of this pipe shaft 14c is attached to pass through the worm wheel 14b and the pipe shaft 14c. .

The tip of the rod 15 is connected to the end 11d of the throttle lever 11c via the idle switch 25 as an idle sensor to control the engine E.
It is designed to come into contact with the engine when the engine is in idle operation.

Here, the idle switch 25 is a switch that is turned on (closed) when the engine is idling, and turned off (open) at other times.

Note that the rod 15 is formed with a long hole 15b, and a pin (not shown) on the actuator body side is guided into this long hole 15b, thereby preventing the rod 15 from rotating. It's getting messy.

In this way, the tip of the rod 15 is in contact with the engine E when it is in idle operation, so by rotating the motor 13 in a certain direction, the pipe shaft 14c is rotated via the worm gear, and the rod 15 is rotated. When the rod 1 is protruded (advanced) from the actuator 12, the throttle valve 11 is opened and the motor 13 is rotated in the opposite direction.
5 into the actuator 12, the throttle valve 11 can be controlled to close by the action of the return spring.

Further, a throttle sensor 20 is provided to detect the opening degree of the throttle valve 11 (throttle opening degree), and a potentiometer or the like that generates a voltage proportional to the throttle opening degree is used as the throttle sensor 20. It will be done.

Furthermore, as shown in FIG. 2, a water temperature sensor 2 detects the cooling water temperature as the warm-up temperature of the engine E.
1, and a rotational speed sensor 17 that detects the engine rotational speed using ignition pulse information obtained from, for example, the primary negative terminal of the ignition coil 32.

Furthermore, a vehicle speed sensor 24 is provided which detects the vehicle speed using a pulse signal having a frequency proportional to the vehicle speed, and a known reed switch is used as the vehicle speed sensor 24.

Further, a cranking switch 26 is provided as a cranking sensor that detects the engine cranking state, and this cranking switch 26 is turned on (closed) when the starter motor is turned on, and turned off (open) otherwise. This is a switch.

By the way, the air flow sensor 16 detects the number of Karman vortices generated by a columnar body disposed in the intake passage 1 by using ultrasonic modulation means or by detecting a change in resistance value. This detects the amount of intake air in the intake passage 1, and the digital output from the air flow sensor 16 is input to the controller 29. Note that the digital output from the air flow sensor 16 is applied to, for example, a 1/2 frequency divider within the controller 29, and then used for a throttle sensor failure determination process, etc., which will be described later.

In addition, it is generally said that the air flow sensor 16 malfunctions due to intake pulsation or the like when the engine E is running at low speed and under high load. However, in this embodiment, an intercooler 8 is provided downstream of the air flow sensor 16, and the dimensions of the air cleaner portion are adjusted accordingly. As a result, the intake pulsation as described above almost no longer occurs, so it is considered that the measurement reliability or accuracy by the air flow sensor 16 is sufficiently high.

In addition to the above-mentioned sensors and switches, there is also an intake air temperature sensor 18 that detects intake air temperature, an atmospheric pressure sensor 19 that detects atmospheric pressure, an O ₂ sensor 22 that detects oxygen concentration in exhaust gas, and a knock sensor that detects engine knock status. 23, a crank angle sensor 27 that detects the crank angle by a photoelectric conversion means with a distributor 33, a reference opening of the throttle valve 11 (this opening is determined based on, for example, the engine
It is set as a small opening corresponding to around 600 rpm. ) A motor position switch 28 as a position sensor that detects the position (reference position) of the rod 15 of the actuator 12 corresponding to
etc., and signals from these sensors and switches are input to the controller 29.

Note that the motor position switch 28 is
As shown in the figure, it is provided behind the rear end surface of the rod 15, and is configured to be turned on (closed) when the rod 15 is in the most retracted state, and turned on (opened) at other times.

In addition, an intake temperature sensor 18, an atmospheric pressure sensor 19,
Since the detection signals of the water temperature sensor 21, throttle sensor 20, _O2 sensor 22, knock sensor 23, etc. are analog signals, they are input to the controller 29 via the A/D converter.

Note that the atmospheric pressure sensor 19 may be incorporated into the controller 29.

Further, an ignition coil 32 is provided, and this ignition coil 32 is connected to a power transistor 3 as a switching transistor.
0, the primary side current is turned on and off.

Furthermore, a display meter 35 is provided in the vehicle interior.

The display meter 35 may have a needle-type display section 35a or a segment-type display section 35b in which light emitting diodes (LEDs) are arranged in a row and these LEDs blink as appropriate. .

By the way, the controller 29 is configured with a CPU, a memory (including a map), and an appropriate input/output interface, but when the idle switch 25 detects the idle operating state (when the idle switch is turned on), the controller 29 Under the set conditions, rotation speed sensor 1
The engine speed feedback control (rotation speed feedback control) is performed by the signal from the throttle sensor 20, and the position of the throttle valve 11 is controlled by the signal from the throttle sensor 20 under other set conditions at the time of detecting the idle state. In order to perform shock feedback control, an idle switch 25, a rotation speed sensor 17, a throttle sensor 2
0. It has the function of an idle control means M1 that receives detection signals from the vehicle speed sensor 24 and outputs an idle control signal based on these detection signals to the motor 13 of the actuator 12.

Furthermore, when performing rotation speed feedback control, the target engine speed is changed according to the cooling water temperature as shown in Fig. 4, and when performing position feedback control, the target throttle opening is changed according to the cooling water temperature. is changed as shown in FIG.

Furthermore, the relationship between the driving time ΔD of the motor 13 of the actuator 12 and the deviation ΔN or ΔP is as shown in FIGS. 6 and 7, respectively. Here, the deviation ΔN means the difference between the actual engine speed and the target engine speed, and the deviation ΔP means the difference between the actual throttle opening and the target throttle opening.

Although the above conditions have already been described, this condition refers to a case where at least the following items are satisfied, and refers to a condition in which the engine is relatively stable.

(1) A predetermined period of time has elapsed after the idle switch 25 was turned from off to on.

(2) The vehicle speed is extremely low (for example, 2.5 km/h or less).

(3) The deviation of the actual engine speed (actual speed) from the target speed must be within a specified range.

(4) For vehicles equipped with a cooler, a predetermined period of time must have elapsed after the cooler relay, etc. was switched in accordance with the cooler load.

Further, the above conditions refer to conditions when the above conditions are not satisfied, the engine is relatively unstable, and rapid feedback control is desired.

Furthermore, the flow of processing by this idle control means M1 is shown in FIG. That is, first, in step A1, various data are input, and then in step A2, it is determined whether the engine is in an idling operating state. If the vehicle is in an idling state, the YES route is taken in step A2, and it is determined in step A3 whether the above conditions are met. If the conditions are such that it is desired to perform rotational speed feedback control, step A4
, the rotational speed feedback control mode is selected.

As a result, engine speed feedback control is performed on the engine E so that the engine speed reaches the target engine speed.

If it is determined in step A3 that the condition is satisfied, the position feedback control mode is selected in step A5.

As a result, position feedback control is performed on the engine E so that the target throttle opening is achieved.

Note that even if any of the above conditions are satisfied, if it is impossible to control the throttle opening below the minimum throttle opening or above the maximum throttle opening, the controller 29 will not output.

Furthermore, the controller 29 has the function of a throttle sensor failure determining means J that determines whether the throttle sensor 20 has an output disconnection failure. The flow of processing for such means J is shown in FIG. 1.

That is, first, in step B1, data from the air flow sensor 16, rotation speed sensor 17, throttle sensor 20, etc. are input, and in step B2, the detected throttle opening θ is set to the set value θ ₀
, and the ratio A/N between the detected intake air amount A and engine speed N is the set value (A/N).
N) is smaller than ₀ , and the detected engine speed N is larger than the set value _N0 (theoretically, the engine speed does not need to be zero) for a predetermined period of time (for example, 0.5 seconds). It will be determined whether there is.

Here, the intake air amount A is the intake temperature T and the atmospheric pressure AP.
It is assumed that the set value θ ₀ , (A/N) ₀ or N ₀ is positive unless otherwise specified.

Also, A/N is proportional to the density inside the intake passage 1 (density inside the manifold), and the density inside the intake passage 1 is proportional to the intake passage pressure (P/T), so this A/N information is This means that it has engine load information similar to the information in . That is, A/N
Since there is a unique correspondence between the information and the information on the throttle opening θ, the throttle opening θ can be determined from the A/N information.
information can be estimated.

Also, when engine E is stopped, N
= 0, the value of A/N has no meaning.

By the way, when the throttle opening degree θ is larger than the set value θ ₀ , it is not known whether this is due to a disconnection failure in the throttle sensor 20 or whether the throttle opening degree is increased by depressing the accelerator pedal.

However, as mentioned above, since the A/N information corresponds to the information on the throttle opening θ, the set value (A/N) to be compared with the A/N is set to ₀ , which is slightly larger than the value in the idling state. If you set it to a small value, the A/N will be reduced even though θ>θ ₀ .
If <(A/N) ₀ is satisfied, it can be seen that the problem is due to a disconnection failure in the throttle sensor 20. In other words, when the throttle opening increases by depressing the accelerator pedal, θ>θ ₀ and A/
N>(A/N) should be ₀ .

In order for A/N<(A/N) ₀ to have meaning, N>N ₀ must be satisfied, so in the end, in order to measure the disconnection failure of the throttle sensor 20,
All of the following conditions must be satisfied: θ>θ ₀ , A/N<(A/N) ₀ and N>N ₀ .

In addition, if the throttle sensor 20 causes a wire breakage failure, the above conditions will be continuously satisfied, so it is avoided that the throttle sensor 20 is determined to have a wire breakage failure due to a temporary malfunction etc. Therefore, if the conditions of θ>θ ₀ , A/N<(A/N) ₀ , and N>N ₀ continue for a predetermined period of time or more, it is determined that the throttle sensor 20 is in a disconnection failure state. be.

Therefore, if YES is determined in step B2, it is determined that the throttle sensor 20 has a disconnection failure, and the flag S1 is set to 1 in step B3.

If the answer is NO in step B2, flags S1=0 and S4=0 are set in steps B4 and B5.

Further, the controller 29 receives a determination signal from the throttle sensor failure determination means J and a signal from the motor position switch 28, and is used for calibration to drive the rod 15 to the reference position where it is retreated when the throttle sensor 20 fails. In addition to having the function of a calibration control means M2 that outputs a control signal to the motor 13, the reference position is detected from the motor position switch 28 while the throttle sensor failure determination signal from the throttle sensor failure determination means J is being input. When the signal is input, the failure idle opening control means M3 uses this reference position detection signal as a trigger signal to output a throttle opening control signal to the motor 13 to bring the throttle valve 11 into a predetermined idle opening state. It also has the function of

First, the processing performed by the calibration control means M2 will be explained using FIG. That is, in step C1, data such as the motor position switch 28 is input, and in step C2, the flag is
It is determined whether S1=1. If the throttle sensor 20 has a disconnection failure, flag S1 = 1 as is clear from Fig. 1, so take the YES route at step C2 and proceed to the next step.
C2' checks whether S4=1. Since S4 is initially S4=0, the NO route is taken and in the next step C3, it is determined whether flag S2=1.

Note that even if S1=1, if the processing by the failure idle opening control means M3, which will be described later, is completed and the throttle valve 11 is in the set opening state, S4=1.
Since it is set to 1, no processing is performed through the YES route.

At first, flag S2=0, so step C
The NO route is taken in step C4, and it is determined in step C4 whether the motor position switch 28 is on (closed). Normally, the rear end of the rod 15 is in front of the motor position switch 28, so the motor position switch 28 is off (open).
Therefore, step C4 takes the NO route, and in step C5, motor 13 is activated with pulse width L1.
is driven to drive the rod 15 backward.

Here, since the pulse width L1 is set relatively large, the rod 15 is driven largely backward.

As a result of the rod 15 being moved backward in this way, the motor position switch 28 is turned on (closed). In step C6, the flag S2 is set to 1, and in step C7, the motor position switch 28 is turned off (opened). Since the motor position switch 28 is on at this time, in step C8, the pulse width L2 is
(<L1) to drive the motor 13 and
5 is driven forward.

Here, since the pulse width L2 is set relatively small, the degree of advancement of the rod 15 is small. After this process, the process returns and, for example, when the next timer interrupt signal is input, steps C1 and C are executed again.
2, C2', and C3 are performed, but in this case, since S2=1 is set at step C6,
At step C3, the process jumps to step C7, and then steps C7 and C8 are processed.

In this way, as the rod 15 gradually moves forward, the motor position switch 28
turns off. This causes the rod 15 to take the reference position.

Therefore, after that, the YES route is taken in step C7, and the process of setting S3=1 is performed in step C9. Here, the process of setting the flag S3=1 is a process that indicates that the calibration of the rod 15 has been completed.

Next, the processing performed by the failure idle opening degree control means M3 will be explained using FIG. 10.

That is, first in step D1, flag S1=
1 or not is determined.

When the throttle sensor fails, S1=1, so
At step D1, the YES route is taken, and at the next step D2, it is determined whether flag S3=1.

If the calibration of the rod 15 has been completed, that is, if the rod 15 is at the reference position, S3 = 1, so the YES route is taken in step D2, and the adjustment is made according to the set throttle opening in the next step D3. A motor drive time ΔD is set in a timer, and in step D4, the motor 13 is driven until the timer reaches 0.

As a result, the rod 15 moves further forward, and the throttle valve 11 enters a predetermined idle opening state. In this way, even if the throttle sensor 20 has a disconnection failure, the throttle valve 11 is adjusted to the set opening degree, so the engine will not stall.

Note that when the rod 15 moves forward to a predetermined position,
At steps D5, D6, and D7, S1=0, S3=0,
Setting S4=1 is performed. Here, S4=
1 is a flag indicating completion of setting.

Also, once the rod 15 is moved to the above-mentioned set throttle opening position, the
S4=1 is set, and thereafter, the failure condition of the throttle sensor 20 is satisfied (S1=1 and S4=1).
1) does not move the motor 13.

That is, when it is determined that the throttle sensor 20 is malfunctioning, the throttle valve 11 is maintained at the set opening state until the malfunction is released.

By the way, this controller 29 takes into account the installation error of the throttle sensor 20 and uses the air flow sensor 16 during idle speed control.
The throttle opening degree is calibrated based on the output from the
After that, learning control for such calibration is also performed, but when performing such learning, limits are imposed on the values to be learned. That is, if a too large value is received as a learning value (for example, if the throttle sensor 20 has a disconnection failure and a value corresponding to a fully open throttle is received), this value is excluded from the learning target. Such limitations are:
This is imposed not only during engine idle control but also during normal operation.

Furthermore, after it is determined that the throttle sensor 20 has failed, the learned value is reset to the initial value. This is to ensure that the engine E does not operate at an abnormally high rotational speed during idling after the throttle sensor fails, as described in the section on the problems with the conventional device.

The controller 29 also includes, for example, a display 35.
If is a boost meter, air flow sensor 1
6. Receives signals from the rotation speed sensor 17, intake temperature sensor 18, and atmospheric pressure sensor 19, information on intake air amount A, information on engine rotation speed N, information on intake temperature T,
It has the function of an intake passage pressure display control means M4 that outputs a signal corresponding to the intake passage pressure P to the display 35 based on information on the atmospheric pressure AP.

Now, focusing on the intake passage pressure display process, the flow of the process performed in the controller 29 is briefly shown in FIG. 11. That is, in step E1 of FIG. 11, the air flow sensor 16,
Input each data from the rotation speed sensor 17, intake temperature sensor 18, and atmospheric pressure sensor 19, and proceed to the next step.
At E2, A/N is calculated from the intake air amount A and the engine speed N, which have been corrected according to the intake air temperature T and atmospheric pressure AP.

As mentioned above, this A/N is proportional to the density inside the intake passage 1 (density inside the manifold), and the density inside the intake passage 1 is proportional to the intake passage pressure (P/T). If T is known, the intake passage pressure P is also known, so in step E3, a drive signal (display signal) corresponding to the A/N with information on the intake passage pressure P is output to the display 35 as described above. be done. As a result, the intake passage pressure is displayed on the display 35. In this case, the signal output to the display 35 is a current signal, but may be a voltage signal.

Furthermore, the controller 29 gives priority to the intake passage pressure display control means M4 based on the determination signal from the throttle sensor failure determination means J, and controls the display 3
It also has the function of a failure display control means M5 that outputs a throttle sensor failure indication signal to the throttle sensor failure indication signal M5.

Next, the flow of processing mainly performed by the throttle sensor failure determination means J and failure display control means M5 is shown in FIG. 12.

First, data from various sensors and switches are input in step F1, and then in step F2.
Then, it is determined whether the flag S1 is 1 or not. If the throttle sensor 20 is malfunctioning, the first
As can be seen from the figure, since the flag S1 is set to 1, if the throttle sensor 20 is out of order, the YES route is selected in step F2.

In this way, if it is determined YES in step F2, it is determined that the throttle sensor 20 is malfunctioning, and in step F3, the malfunction display control means M5 takes priority over the intake passage pressure display control means M4. Then, a failure indication signal is output to the display 35, thereby causing the display 35 to display that the throttle sensor 20 is malfunctioning.

As a method of indicating a failure, for example, the value indicated by the needle is set to a constant value regardless of the operating state. By continuing to point to a constant value in this way, a warning is given that the throttle sensor 20 is out of order.

If the result in step F2 is NO, that is, S1=0, then in step F4, the intake passage pressure display control means M4 causes the display 35 to display the normal intake passage pressure. The specific means are as described above.

The controller 29 also includes fuel supply control means that receives signals from the above-mentioned sensors and switches and outputs signals for supplying fuel to the electromagnetic fuel injection valves 9 and 10 in accordance with the operating state of the engine E; An ignition timing control means outputs an ignition timing control signal according to the operating state of the engine E, and a two-diaphragm pressure response device 7 is used to adjust the opening timing of the waste gate valve 6 in order to obtain different boost pressure characteristics. It also has the function of a wastegate valve control means that outputs a signal to the electromagnetic switching valve 24 to be controlled (this valve 24 has a return spring (not shown) for the valve body).

As mentioned above, since the A/N information has intake passage pressure information, this is used as engine load information, and the engine operating state is detected from this information and engine speed information to control fuel supply. etc. are being carried out.

In other words, the air flow sensor 16, rotation speed sensor 17, intake air temperature sensor 18, and atmospheric pressure sensor 19 are not only used to display the intake passage pressure P, but are originally used for electronic fuel supply control. Therefore, the air flow sensor 16, rotation speed sensor 17, etc. are not newly provided to display the intake passage pressure.

In addition to the boost meter, the controller 2
A device driven by the signal from 9, such as a speedometer or tachometer, may also be used.

Incidentally, the reference numeral 36 in FIG. 2 indicates an ignition key switch, and the reference numeral 37 indicates a battery.

Also, in FIG. 2, a line directly connected from the battery 37 to the controller 29 is connected to a backup memory within the controller 29.

〔Effect of the invention〕

As described in detail above, the throttle sensor failure determination device of the present invention includes a throttle sensor that detects the opening degree of the throttle valve provided in the intake passage of the engine, and detects output disconnection failure of the throttle sensor. In order to determine this, an air flow sensor that detects the intake air in the engine intake passage and a rotation speed sensor that detects the engine rotation speed are provided. A value (A/ N) is smaller than the second predetermined value regarding A/N corresponding to the opening degree of the throttle valve that is smaller than the opening degree of the throttle valve corresponding to the predetermined amount, the output of the throttle sensor is in a disconnection failure state. The following effects and advantages can be obtained with a simple configuration in which a failure determining means is provided that determines that there is a problem and outputs a signal to that effect.

(1) Even if the throttle sensor has an output disconnection failure, it is possible to reliably determine this condition, that is, it is determined that the throttle valve is not actually fully open, and for example, move the actuator to the reference position. After calibration, the actuator can be properly driven until the throttle valve reaches the predetermined idle opening state.
When the throttle sensor fails as described above, the throttle valve is incorrectly determined to be fully open based on the throttle sensor output corresponding to the fully open throttle valve, and the throttle valve is controlled in the direction of closing. It is possible to reliably avoid a situation where the engine stops due to excessive engine idle control, contributing to the realization of highly reliable engine idle control.

(2) When the throttle sensor has an output disconnection failure, it is possible to reliably determine the throttle sensor output disconnection state and supply a signal indicating that the throttle sensor is malfunctioning to, for example, a display means. In this way, it is possible to reliably display information as to whether or not the throttle sensor is malfunctioning, which is convenient.

[Brief explanation of drawings]

The figure shows an engine idle control device having a throttle sensor failure determination device as an embodiment of the present invention. FIG. 1 is a flowchart showing the procedure for determining the throttle sensor failure, and FIG. 2 is the overall configuration. Figure 3 is a diagram showing the main parts of the system, Figures 4 to 7 are graphs for explaining its functions, and Figure 8 is
Figures 1 to 12 are flowcharts for explaining their actions. 1...Intake passage, 2...Exhaust passage, 3...Turbocharger, 4...Turbine, 5...Compressor, 6...
Waste gate valve, 7...pressure response device, 8...
Intercooler, 9, 10...Electromagnetic fuel injection valve, 1
1... Throttle valve, 11a... Shaft, 11c... Throttle lever, 11d... Throttle lever end, 1
2... Actuator, 13... Motor, 14a... Worm, 14b... Worm wheel, 14c... Pipe shaft, 14d... Female threaded portion, 15... Rod, 15
a...Male thread part, 15b...Elongated hole, 16...Air flow sensor, 17...Rotation speed sensor, 18...Intake temperature sensor, 19...Atmospheric pressure sensor, 20...Throttle sensor, 21...Water temperature sensor, 22...O ₂ sensor, 23
...Knock sensor, 24...Vehicle speed sensor, 25...Idle switch, 26...Cranking switch, 2
7... Crank angle sensor, 28... Motor position switch, 29... Controller, 30... Power transistor, 31... Catalytic converter, 32... Ignition coil, 33... Distributor, 34... Electromagnetic switching valve, 35... Display Vessel, 35a
...Needle type display section, 35b...Segment type display section, 3
6...Ignition key switch, 37...Battery, E...Engine, J...Throttle sensor failure determination means, M1...Idle control means, M2...Calibration control means, M3...Failure idle opening control means, M
4...Intake passage pressure display control means, M5...Failure display control means.

Claims (1)

[Claims] 1 Equipped with a throttle sensor that detects the opening degree of the throttle valve installed in the intake passage of the engine,
It is necessary to determine whether there is an output disconnection failure of the throttle sensor.
An air flow sensor that detects the amount of intake air in the engine intake passage and a rotation speed sensor that detects the engine speed are provided, and the throttle valve opening is larger than the idle opening when the value detected by the throttle sensor is larger than the idle opening. A value (A/N) obtained by dividing the intake air amount information detected by the air flow sensor by the engine rotation speed information detected by the rotation speed sensor in a state that is larger than a predetermined value corresponding to If the throttle sensor is smaller than the second predetermined value related to the A/N corresponding to the opening of the throttle valve which is smaller than the opening of the throttle valve corresponding to the predetermined value, it is determined that the output of the throttle sensor is in a disconnection failure state. A throttle sensor failure determination device, characterized in that a failure determination means is provided for outputting a signal to that effect.