JP3435886B2 - Throttle abnormality detection device for internal combustion engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine which detects a throttle abnormality in a throttle control system called "electronic throttle system" for controlling a throttle valve opening by driving a DC motor according to the depression amount of an accelerator pedal. The present invention relates to a throttle abnormality detecting device.

[0002]

2. Description of the Related Art Conventionally, as a prior art document related to a throttle abnormality detecting device for an internal combustion engine for detecting a throttle abnormality in an electronic throttle system, Japanese Patent Publication No. 4-5 is available.
The one disclosed in Japanese Patent No. 02656 is known.
In this technology, a technology for monitoring the current value supplied to the motor, determining that the current value is normal if the current value is within a predetermined area, and determining some abnormality when the current value is outside the predetermined area, and performing a fail-safe operation is shown. .

Here, with respect to the transition of the throttle opening command value, the actual throttle opening of the throttle valve and the motor current flowing through the DC motor at that time transit as shown in FIG. That is, even when the DC motor is operating normally, a large inrush current flows at the start of rotation, and a large brake current in the reverse rotation direction for applying a brake flows at the time of rotation stop.

Therefore, in the prior art, a large current such as an inrush current or a brake current is excluded so as not to be erroneously determined to be a throttle abnormality, and only a steady current flowing when the rotation of the DC motor is stopped is detected and determined. . As a result, a completely stuck state is detected in which foreign matter has entered the throttle valve and is bitten, or fuel or oil has adhered to the throttle valve and a very large load is applied to stop the rotation of the throttle valve.

[0005]

By the way, it is impossible to detect the throttle abnormality in the initial stage where the throttle valve is not completely fixed and the DC motor is somehow rotating although the viscous resistance is large due to oil or the like. . Moreover, at this time, a large current continues to flow halfway through the DC motor for a long time, and the temperature of the motor winding gradually rises, which may eventually burn the DC motor.

Further, the return spring that constantly urges the throttle valve to the fully closed side or the like has a role of returning the throttle valve to the fully closed side or the like when the throttle is abnormal. By the way, when the return spring of the throttle valve is broken, the urging force is lost and the motor current flowing through the DC motor is reduced by that amount. However, during normal traveling, the DC motor keeps moving the throttle valve and the motor current is It continues to fluctuate, and it is impossible to detect breakage of the return spring in this state.

Therefore, the present invention has been made in order to solve such a problem, and it is an object of the present invention to provide a throttle abnormality detecting device for an internal combustion engine capable of surely detecting a throttle abnormality in an electronic throttle system even when a DC motor is operating. I am trying.

[0008]

A throttle abnormality detecting device for an internal combustion engine according to a first aspect of the present invention comprises a throttle control means for controlling a throttle valve opening by driving a DC motor according to the amount of depression of an accelerator pedal. Is it a DC motor ?
Load torque estimating means for estimating the load, and the load
A fluctuation amount detecting unit that detects a fluctuation amount of the estimated load torque estimated by the torque estimating unit for each predetermined time, and a throttle abnormality is detected based on the fluctuation amount of the estimated load torque detected by the fluctuation amount detecting unit. And an abnormality detecting means.

According to a second aspect of the present invention, there is provided a throttle abnormality detecting device for an internal combustion engine, wherein the throttle valve is fixed when the variation amount in the abnormality detecting means of the first aspect exceeds a predetermined value determined by a nominal maximum load torque. It is a judgment.

In the throttle abnormality detecting device for an internal combustion engine according to claim 3, the fluctuation amount in the abnormality detecting means according to claim 1 or 2 is determined by a nominal minimum load torque.
Circle is to determine that the breakage of the return spring of the throttle valve when a predetermined value or less.

[0011]

In the throttle abnormality detecting apparatus for the internal combustion engine according to the first aspect of the present invention, the throttle control means drives the DC motor according to the depression amount of the accelerator pedal to control the opening of the throttle valve, and the load torque estimating means controls the DC motor. Nika
The load torque is estimated , and the variation amount of the estimated load torque at every predetermined time is detected by the variation amount detecting means, and the abnormality detecting means detects the throttle abnormality based on the variation amount.

According to the abnormality detecting means of the throttle abnormality detecting device for the internal combustion engine of the second aspect, in addition to the operation of the first aspect, when the amount of fluctuation exceeds a predetermined value determined by the nominal maximum load torque , the throttle valve is stuck. It is determined that there is.

In the abnormality detecting means of the throttle abnormality detecting device for an internal combustion engine according to claim 3, in addition to the action of claim 1 or 2, the fluctuation amount is not more than a predetermined value determined by the nominal minimum load torque. When it becomes, it is determined that the return spring of the throttle valve is broken.

[0014]

EXAMPLES The present invention will be described below based on specific examples.

FIG. 1 is a schematic diagram showing the overall construction of a throttle control device for an internal combustion engine according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 is an internal combustion engine, and air is supplied to the internal combustion engine 1 through an intake passage 2. A throttle valve 3 is provided in the middle of the intake passage 2, and a throttle opening sensor 4 for detecting the throttle opening is provided in the throttle valve 3. Reference numeral 5 denotes an accelerator pedal, and the accelerator pedal 5 has an accelerator opening degree sensor 6 for detecting an accelerator opening degree.
Is provided. Reference numeral 7 denotes a fully closed stopper that regulates the fully closed position of the throttle valve 3.

Reference numeral 10 denotes an ECU (Electronic Control Unit:
The ECU 10 receives a throttle opening signal TH from the throttle opening sensor 4 and an accelerator opening signal Ap from the accelerator pedal 5 to the ECU 10.
12 is a DC motor as an actuator,
Electric current is supplied to the motor 12 from the ECU 10 side. Further, 13 is a gear stage arranged between the DC motor 12 and the throttle valve 3, and 14 is a throttle valve 3
Is a return spring that constantly biases the valve toward the fully closed side.

Next, a description will be given with reference to FIG. 2 showing a main configuration of a throttle control device for an internal combustion engine according to an embodiment of the present invention.

In FIG. 2, an accelerator opening signal Ap from the accelerator opening sensor 6 corresponding to the depression amount of the accelerator pedal 5 and a throttle opening signal from the throttle opening sensor 4 corresponding to the throttle opening of the throttle valve 3. TH is A / D converted by the A / D converter 10a and the ECU 10
Entered in. According to these signals, the ECU 10 outputs a PWM (Pulse Width Modulation) signal to the motor drive circuit 11. Then, a current is passed from the motor drive circuit 11 to the DC motor 12, the DC motor 12 is operated, and the throttle valve 3 is operated via the gear stage 13.
Is opened and closed. At this time, DC from the motor drive circuit 11
The motor current IM supplied to the motor 12 is detected by the current detection circuit 15, and the motor current IM is detected by the A / D converter 1.
It is A / D converted at 0a and input to the ECU 10.

Next, calculation of the motor angular velocity of the DC motor 12 will be described with reference to FIG. 3 showing a general mathematical model. Note that S is a Laplace operator.

In FIG. 3, the torque TM generated by the DC motor 12 is expressed by the following equation (1). Here, Kt is a torque constant [kgf · cm / A] of the DC motor 12, and IM is a motor current [A] input to the DC motor 12.

[0022]

## EQU1 ## TM = Kt × IM (1) Further, the actual torque TP used for actually rotating the DC motor 12 is expressed by the following equation (2). Where J
Is the inertia of the DC motor 12 [kg · cm ² ], ω is DC
It is a motor angular velocity [rad / sec] of the motor 12.

[0023]

## EQU2 ## TP = J.times. (D.omega./dt) (2) Therefore, the load torque TL of the DC motor 12 is expressed by the following equation (3) from the equations (1) and (2). Elements related to the load torque TL include the biasing force of the return spring 14, friction (static friction, dynamic friction, viscous friction), torque of air flowing through the throttle valve 3, inertia of the throttle valve 3, and the like.

[0024]

TL = TM-TP = Kt * IM-J * (dω / dt) (3) where the torque constant Kt and inertia J of the DC motor 12 are values specific to the DC motor 12. Since it is known, by obtaining the motor current IM and the motor angular velocity ω (differentiation of the throttle opening of the throttle valve 3) (3)
The load torque TL in the equation can be estimated. However, in practice, the torque constant Kt and the inertia J of the DC motor 12 have variations due to changes in temperature, changes with time, and the like due to manufacturing, so the estimated values include errors. Therefore, if this load torque TL is estimated periodically (for example, every 10 seconds) and the difference is taken, these variations can be canceled and the load torque fluctuation amount ΔTL can be estimated, which is expressed by the following equation (4). It The manufacturing variation is a constant value within the same individual, and the temperature / time-dependent time constant is several minutes to years.

[0025]

## EQU00004 ## .DELTA.TL = TLn-TLn-1 (4) By the way, if the throttle valve 3 gets stuck, the estimated load torque TL becomes a very large value and a large torque fluctuation amount (a positive value). appear. Further, when the return spring 14 is broken, the value of the estimated load torque TL becomes a very small value and appears as a large torque fluctuation amount (negative value). Therefore, the load torque fluctuation amount ΔTL is | ΔTL
Throttle abnormality can be detected by using the condition for determining whether or not | ≧ KW is satisfied. Here, KW is a throttle abnormality determination constant determined by the nominal maximum load torque, −
KW is a throttle abnormality determination constant determined by the nominal minimum load torque.

Next, the ECU 10 used in the throttle abnormality detecting device for the internal combustion engine according to the embodiment of the present invention.
The processing procedure of is described with reference to the flowchart of FIG.

First, in step S101, it is determined whether T1 time (about 1 ms to 4 ms) has elapsed from the previous determination. When the determination condition of step S101 is not satisfied, this routine is ended. On the other hand, step S1
When the determination condition of 01 is satisfied, step S102
Then, the value θn obtained by A / D converting the throttle opening TH of the throttle valve 3 at time n is obtained. Next, in step S103, the motor angular velocity ω of the DC motor 12 is calculated from the difference between the current value θn and the previous value θn-1 obtained by A / D converting the throttle opening TH of the throttle valve 3.
n is required. Next, the process proceeds to step S104, and DC is calculated from the difference between the current motor angular velocity ωn and the previous value ωn-1.
The motor angular acceleration Δωn of the motor 12 is obtained.

Next, the process proceeds to step S105, where time n
A value IMn obtained by A / D converting the motor current IM at Then, the process proceeds to step S106, and step S
Substituting the motor angular acceleration Δωn obtained in step 104 and the motor current IMn obtained in step S105 into the equation (3), the estimated load torque TLn of the DC motor 12 is given by the following equation (5).
Is required as shown in.

[0029]

TLn = Kt × IMn−J × Δωn (5) Next, the process proceeds to step S107, and the estimated load torque TLn at time n obtained in step S106 and the estimated load torque TL10s 10 seconds before are calculated. The load torque fluctuation amount ΔTLn is obtained from the difference between Next, in step S108, it is determined whether the load torque variation amount ΔTLn is equal to or greater than the throttle abnormality determination constant KW determined by the nominal maximum load torque. If the determination condition of step S108 is satisfied, it is determined that the throttle valve 3 has become stuck for some reason, and the process proceeds to step S109 to display a sticking warning of the throttle valve 3 and then to step S11.
The operation proceeds to 0, the power supply to the DC motor 12 is stopped, and this routine ends. At this time, as shown in FIG.
The biasing force of the return spring 14 is the throttle valve 3
And is forcibly pulled until it comes into contact with the fully closed stopper 7, and the throttle opening of the throttle valve 3 becomes the fully closed position.

On the other hand, when the determination condition of step S108 is not satisfied, the routine proceeds to step S111, where it is determined whether the load torque fluctuation amount ΔTLn is less than or equal to the throttle abnormality determination constant −KW determined by the nominal minimum load torque.
When the determination condition of step S111 is satisfied, it is determined that the return spring 14 for returning the throttle valve 12 to the fully closed side is broken, the process proceeds to step S112, a return spring breakage warning is displayed, and this routine is ended. On the other hand, if the determination condition of step S111 is not satisfied, that is, if -KW <ΔTLn <KW, it is determined that there is no throttle abnormality, and this routine ends. By such processing, it becomes possible to always detect the abnormality of the throttle valve 3 even when the DC motor 12 is operating.

As described above, the throttle abnormality detecting apparatus for the internal combustion engine of this embodiment is achieved by the ECU 10 which controls the opening degree of the throttle valve 3 by driving the DC motor 12 according to the depression amount of the accelerator pedal 5. EC for estimating the load torque applied to the throttle motor and the DC motor 12
Load torque estimation means achieved in U10, and the load
A fluctuation amount detecting means achieved by the ECU 10 for detecting the load torque fluctuation amount ΔTL of the estimated load torque TL estimated by the torque estimating means for each predetermined time of 10 seconds, and the estimated load torque detected by the fluctuation amount detecting means. E to detect a throttle abnormality based on the load torque fluctuation amount ΔTL of TL
The CU 10 is provided with an abnormality detecting means, which can be the embodiment of claim 1.

Therefore, the throttle control means drives the DC motor 12 in accordance with the depression amount of the accelerator pedal 5 to control the opening of the throttle valve 3, and the load torque estimating means applies a load to the DC motor 12 . The torque is estimated, and the estimated load torque TL is estimated for a predetermined time 10
The load torque fluctuation amount ΔTL for each second is detected by the fluctuation amount detection means, and the abnormality detection means detects the throttle abnormality based on the load torque fluctuation amount ΔTL. Therefore, the throttle abnormality in the electronic throttle system can be reliably detected even while the DC motor is operating, and quick action can be taken when the throttle abnormality occurs.

Further, the abnormality detecting means achieved by the ECU 10 in the throttle abnormality detecting apparatus for the internal combustion engine according to the present embodiment is such that the throttle valve is used when the fluctuation amount becomes a predetermined value or more determined by the nominal maximum load torque. It is determined to be the fixation of No. 3, and this can be the embodiment of claim 2.

Therefore, in the abnormality detecting means, when the fluctuation amount is equal to or larger than the predetermined value, that is, the load torque fluctuation amount with respect to the DC motor becomes larger than the abnormality judgment constant determined by the nominal maximum load torque, it is judged that the throttle valve is stuck. It Therefore, in addition to being able to reliably detect a throttle abnormality, which is a completely fixed state of the throttle valve in the electronic throttle system, during the operation of the DC motor, it is possible to set the predetermined value appropriately to prevent the throttle valve from being completely fixed from the initial stage. It is also possible to detect unstable behavior and prevent burning of the DC motor.

In the abnormality detecting means achieved by the ECU 10 in the throttle abnormality detecting apparatus for the internal combustion engine of this embodiment, the fluctuation amount is determined by the nominal minimum load torque.
That when equal to or less than a predetermined value are those determined to be the breakage of the return spring 14 of the throttle valve 3 can be the same as the embodiment of claim 3.

Therefore, in the abnormality detecting means, when the variation amount is less than the predetermined value, that is, when the variation amount of the load torque for the DC motor is smaller than the abnormality determination constant determined by the nominal minimum load torque, the return spring of the throttle valve is broken. Is determined. Therefore, the throttle abnormality, which is the breakage of the return spring of the throttle valve in the electronic throttle system, can be reliably detected during the operation of the DC motor.

[0037]

As described above, according to the throttle abnormality detecting device for the internal combustion engine of the first aspect, the throttle control means drives the DC motor according to the depression amount of the accelerator pedal to control the opening of the throttle valve. And load torque
The estimation means estimates the load torque applied to the DC motor,
The variation amount of the estimated load torque for each predetermined time is detected by the variation amount detecting means, and the abnormality of the throttle is detected by the abnormality detecting means based on the variation amount. As a result, a throttle abnormality in the electronic throttle system can be reliably detected even when the DC motor is operating, and quick action can be taken against the throttle abnormality.

According to the throttle abnormality detecting device for the internal combustion engine of the second aspect, in addition to the effect of the first aspect, when the variation amount in the abnormality detecting means exceeds a predetermined value determined by the nominal maximum load torque , the throttle valve It is determined to be fixed. As a result, it is possible to reliably detect the throttle abnormality, which is the completely fixed state of the throttle valve in the electronic throttle system, during the operation of the DC motor. Further, by properly setting the predetermined value, it is possible to detect an unstable behavior from the initial stage before complete fixation and prevent the DC motor from burning.

According to the throttle abnormality detecting apparatus for the internal combustion engine of the third aspect, in addition to the effect of the first or second aspect, the variation amount by the abnormality detecting means depends on the nominal minimum load torque.
When determined equal to or less than a predetermined value is determined to be the breakage of a return spring of the throttle valve. Accordingly, it is possible to reliably detect the throttle abnormality, which is the breakage of the return spring of the throttle valve in the electronic throttle system, during the operation of the DC motor.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a throttle abnormality detecting device for an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a main configuration of a throttle abnormality detecting device for an internal combustion engine according to an embodiment of the present invention.

FIG. 3 is a block diagram showing a general mathematical model of a DC motor used in a throttle abnormality detecting device for an internal combustion engine according to an embodiment of the present invention.

FIG. 4 is a flowchart showing a processing procedure of an ECU used in the throttle abnormality detecting device for the internal combustion engine according to the embodiment of the present invention.

FIG. 5 is a diagram showing that a throttle abnormality is detected by the throttle abnormality detecting device for an internal combustion engine according to an embodiment of the present invention.
It is explanatory drawing which shows the state when electricity supply to a C motor is stopped.

FIG. 6 is a time chart showing a motor current detected during normal operation in a conventional electronic throttle system in association with a throttle opening command value and an actual throttle opening.

[Explanation of symbols]

1 Internal combustion engine 3 Throttle valve 4 Throttle opening sensor 5 accelerator pedal 6 Accelerator position sensor 10 ECU (electronic control unit) 12 DC motor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI F02D 45/00 314 F02D 45/00 314H (72) Inventor Kazunori Nonoyama 1-chome, Showa-cho, Kariya city, Aichi Japan Denso Co., Ltd. (56) References JP-A-6-146977 (JP, A) JP-A-7-4296 (JP, A) JP-A-6-311774 (JP, A) JP-A-6-213049 (JP, A) JP-A-3-31529 (JP, A) JP-A-2-256839 (JP, A) JP-A-4-502656 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F02D 41/22 310 F02D 9/02 351 F02D 11/10 F02D 45/00 314

Claims (3)

(57) [Claims] 1. A throttle control means for controlling a throttle valve opening by driving a DC motor according to a depression amount of an accelerator pedal, and a load torque controller for estimating a load torque applied to the DC motor.
And an estimated load torque estimated by the load torque estimating means.
A variation amount detecting means for detecting the amount of change per predetermined time of the click, and an abnormality detecting means for detecting a throttle abnormality based on <br/> variation of the estimated load torque detected by said variation detecting means A throttle abnormality detection device for an internal combustion engine, comprising: 2. The abnormality detecting means is configured so that the fluctuation amount is nominal.
The throttle abnormality detecting device for an internal combustion engine according to claim 1, wherein it is determined that the throttle valve is stuck when the value exceeds a predetermined value determined by the maximum load torque . 3. The abnormality detecting means is configured so that the fluctuation amount is nominal.
The throttle abnormality detecting device for an internal combustion engine according to claim 1 or 2, wherein it is determined that the return spring of the throttle valve is broken when it becomes a predetermined value or less determined by the minimum load torque .