JP6115497B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine that suppresses the generation of abnormal noise from a belt that transmits the rotational driving force of the internal combustion engine to surrounding equipment (auxiliary equipment).

  For example, in a vehicle equipped with an internal combustion engine, the rotational driving force of the crankshaft is transmitted to the pulleys of surrounding equipment (air conditioner compressor, alternator, water pump, etc.) via a belt driven by the crank pulley. In this belt for transmitting the rotational driving force, the friction coefficient changes as wear progresses, and so-called stick-slip is likely to occur. Belt stick-slip is self-excited vibration caused by repeated belt stick (attachment to pulley) and slip (slip on pulley), and abnormal noise is generated when belt stick-slip occurs. .

  For example, in the control apparatus for an internal combustion engine described in Patent Document 1, when the temperature of the belt during idle operation of the vehicle is lower than a predetermined temperature, the first engine speed is higher than the rotation speed during idle operation. The target idle speed is set so that the crankshaft rotation fluctuation rate is lower, thereby suppressing the occurrence of stick-slip of the belt.

  Further, for example, in the hybrid vehicle control device described in Patent Document 2, if it is determined that the timing belt has reached the end of its life, and if the rotational speed of the internal combustion engine is close to the rotational speed at which the timing belt resonates, the rotation of the internal combustion engine Change the number and prolong the timing belt.

JP 2010-174812 A JP 2012-162231 A

  There is a possibility that the stick-slip of the belt may occur in various operating conditions such as a high load and a low temperature. However, in the invention described in Patent Document 1, the occurrence of the stick-slip at a low temperature is suppressed. In Patent Document 1, the degree of belt deterioration (friction coefficient) is not estimated and the occurrence of stick-slip is not predicted. When the temperature is lower than a predetermined temperature, the idle rotation speed is increased regardless of the degree of belt deterioration. And there is a possibility of consuming fuel wastefully.

  In Patent Document 2, the timing belt is not resonated with the internal combustion engine in order to estimate and extend the life of the timing belt, but it does not suppress the occurrence of stick-slip.

  The present invention was devised in view of these points, and predicts the occurrence of stick-slip of a belt that transmits rotational driving force to devices around the internal combustion engine, and the occurrence of stick-slip is predicted. An object of the present invention is to provide a control device for an internal combustion engine that appropriately controls the occurrence of stick-slip in advance.

  In order to solve the above problems, the control device for an internal combustion engine according to the present invention takes the following means. First, a first aspect of the present invention is a control device for an internal combustion engine that suppresses abnormal noise generated from a belt that transmits the rotational driving force of the internal combustion engine to surrounding equipment, wherein the operating state of the internal combustion engine is controlled. Detectable operating state detection means is provided. The control device detects the operation state of the internal combustion engine based on a detection signal from the operation state detection means or based on a control state of the internal combustion engine and the detection signal by itself. The amount of wear of the belt is estimated based on the state, a cumulative amount of wear obtained by integrating the estimated amount of wear is obtained, a friction coefficient of the belt is obtained based on the obtained cumulative amount of wear, and the friction coefficient is determined according to the obtained friction coefficient. Then, the operating state of the internal combustion engine is changed.

  In the first aspect of the invention, the occurrence of stick-slip is predicted from the friction coefficient obtained from the accumulated wear amount of the belt, and the operation state of the internal combustion engine is changed so as to suppress the occurrence of stick-slip of the belt according to the friction coefficient. By, for example, reducing the generated torque, it is possible to appropriately suppress the occurrence of stick-slip when the occurrence of stick-slip is predicted.

  Next, a second invention of the present invention is a control device for an internal combustion engine according to the first invention, wherein the control device is based on the obtained friction coefficient and the operating state of the internal combustion engine. Then, the slip amount of the belt is obtained, and when the obtained slip amount is equal to or greater than a predetermined slip amount, it is determined that an abnormal noise is generated from the belt, and the internal combustion engine is configured so that the slip amount is less than the predetermined slip amount. The operating state of the internal combustion engine is changed by reducing the torque generated by the engine.

  In the second aspect of the invention, the amount of slip of the belt is obtained from the obtained friction coefficient and the operating state of the internal combustion engine, and when the amount of slip is greater than or equal to the predetermined amount of slip, it is predicted that stick slip of the belt will occur. The generated torque of the internal combustion engine is reduced so that the amount is less than the predetermined slip amount. As a result, the occurrence of stick-slip of the belt can be predicted more appropriately, and the occurrence of stick-slip can be more appropriately suppressed.

  Next, a third invention of the present invention is a control device for an internal combustion engine according to the second invention, wherein the control device supplies the generated torque to the internal combustion engine when reducing the torque generated by the internal combustion engine. Reduce fuel consumption.

  In the third aspect of the invention, it is possible to easily and surely reduce the generated torque of the internal combustion engine for suppressing the stick-slip of the belt.

  Next, a fourth invention of the present invention is a control device for an internal combustion engine according to the second or third invention, wherein the control device reduces the torque generated by the internal combustion engine when the torque generated by the internal combustion engine is reduced. When it is determined that the generated torque that has been reduced so that the slip amount is less than the predetermined slip amount is less than the predetermined torque, the warning means is activated to notify.

  In the fourth aspect of the invention, in the case where the reduction amount of the generated torque of the internal combustion engine for suppressing the occurrence of stick-slip of the belt is large and the generated torque of the internal combustion engine has to be reduced to less than a predetermined torque, the belt Is determined to have reached the end of its life and is notified to the user. Thereby, the user can easily know that it is time to replace the belt.

It is a figure explaining the example of the external appearance of each apparatus to which a rotational drive force is transmitted via the internal combustion engine, the belt which transmits the rotational drive force of the said internal combustion engine to the surrounding apparatus, and the said belt. It is a figure explaining the input / output of the control apparatus of the internal combustion engine of this invention. It is a flowchart explaining the example of the process sequence (1st Embodiment) of the control apparatus of an internal combustion engine. It is a figure explaining the example of a driving | running state and belt abrasion amount characteristic. It is a figure explaining the example of a cumulative wear amount and a belt friction coefficient characteristic. It is a figure explaining the example of a driving | running state and a belt slip amount characteristic. It is a flowchart explaining the example of the process sequence (2nd Embodiment) of the control apparatus of an internal combustion engine.

EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing. In the present embodiment, a diesel engine of a vehicle will be described as an example of an internal combustion engine.
● [External appearance of internal combustion engine, belt for transmitting the rotational driving force of the internal combustion engine to peripheral devices, and external examples of the devices for transmitting the rotational driving force via the belt (FIG. 1)]
As shown in the example of the external appearance of FIG. 1, devices (auxiliary devices) such as an air conditioner compressor and an alternator are attached to the internal combustion engine 1 mounted on the vehicle or around the internal combustion engine 1. It is driven via a belt 18. The crank pulley 11 is rotationally driven by the rotation of the crankshaft of the internal combustion engine 1, and the rotational driving force is transmitted to an alternator pulley 13, a water pump pulley 14, a power steering pulley 15, an air conditioner pulley 16 and the like via a belt 18. . Reference numeral 12 denotes a tension adjusting pulley that adjusts the tension of the belt 18.

  The belt 18 is formed using, for example, a rubber composition as a base, and short fibers are exposed on the pulley contact surfaces that come into contact with the pulleys. doing. However, as the wear of the belt progresses, the short fibers deteriorate or disappear, and the friction coefficient of the belt increases and stick slip is likely to occur. The control apparatus for an internal combustion engine according to the present invention predicts that the friction coefficient of the deteriorated belt is increased, predicts the occurrence of stick slip of the belt, and if the occurrence of stick slip is predicted, A measure for suppressing the occurrence is performed.

● [Inputs and outputs of internal combustion engine controller (Fig. 2)]
Next, the input / output of the control device 40 (hereinafter referred to as the control device 40) of the internal combustion engine 1 of the present invention will be described with reference to FIG. The control device 40 (engine control computer or the like) includes detection signals from, for example, intake air amount detection means 21, crank rotation angle detection means 22, cam rotation angle detection means 23, accelerator depression amount detection means 24, water temperature detection means 25, and the like. Is entered. The control device 40 outputs a control signal to, for example, the fuel injection unit 31, the warning unit 32, and the like.

  The intake air amount detection means 21 is, for example, an air flow meter, and outputs a detection signal corresponding to the amount of air that the internal combustion engine 1 takes into the cylinder. The crank rotation angle detection means 22 is, for example, a rotation angle sensor, and outputs a detection signal corresponding to the rotation angle of the crankshaft of the internal combustion engine 1. The cam rotation angle detection means 23 is a rotation angle sensor, for example, and outputs a detection signal corresponding to the rotation angle of the cam that rotates once by two rotations of the crankshaft. The control device 40 can detect the rotation speed and rotation angle of the crankshaft based on the rotation angle and time of the crankshaft. By combining with the rotation angle of the cam, the top dead center timing and the like of each cylinder can be determined. It is possible to detect.

  The accelerator depression amount detection means 24 is an accelerator opening sensor, for example, and outputs a detection signal corresponding to the accelerator depression amount by the user. The control device 40 can detect the user's acceleration request, deceleration request, and the like by detecting the accelerator depression amount. The water temperature detection means 25 is a temperature sensor that detects the temperature of the cooling water of the internal combustion engine, for example, and outputs a detection signal corresponding to the temperature of the cooling water. The control device 40 can detect the warm-up state of the internal combustion engine by detecting the temperature of the cooling water.

  The fuel injection means 31 is an injector that injects fuel into a cylinder of an internal combustion engine, for example, and is driven by a control signal from the control device 40. The control device 40 can change the rotational speed, torque, and the like of the internal combustion engine 1 at the timing and amount of fuel injected from the fuel injection means 31. The warning means 32 is, for example, a warning lamp provided in a meter panel of the vehicle, and is turned on or off by a control signal from the control device 40. For example, if the control device 40 determines that it is time to replace the belt 18 shown in FIG. 1, the control device 40 lights the warning means 32 to notify the user that it is time to replace the belt.

  Each of the detection means corresponds to an operation state detection means, and the control device 40 can detect the operation state of the internal combustion engine 1 based on a detection signal from each of the operation state detection means. The operation state detection means for detecting the operation state of the internal combustion engine 1 is not limited to all the detection means described above, and may be a part of the detection means described above, or not described above. Detection means (for example, intake air temperature detection means, atmospheric pressure detection means, etc.) may be included.

[Processing procedure for suppressing the occurrence of stick-slip of the belt 18 (first embodiment) (FIG. 3)]
The control device 40 is configured as shown in FIG. 3 at a predetermined time interval (for example, every several tens [ms] interval) or every predetermined crank rotation angle (for example, every 180 ° crank rotation angle). Process]. Further, the control device 40 executes the [fuel injection amount calculation process] shown in FIG. 3 at a predetermined timing such as every predetermined crank rotation angle (for example, every 180 ° crank rotation angle). In the following, an example of the processing procedure of [belt noise suppression main processing] in FIG. 3 will be described first.

[Main processing for suppressing abnormal belt noise according to the first embodiment (FIG. 3)]
When the execution of the “belt noise suppression main process” shown in FIG. 3 is started, the control device 40 detects the operating state of the internal combustion engine 1 in step S10 and proceeds to step S15. Note that the operation state of the internal combustion engine 1 detected by the control device 40 is obtained by, for example, the rotation speed of the internal combustion engine 1 obtained based on a detection signal from the crank rotation angle detection means 22 (corresponding to the operation state detection means) or the like. This is the generated torque of the internal combustion engine 1 determined based on the rotational speed and the injection amount from the fuel injection means 31 (corresponding to the control state of the internal combustion engine by itself). Hereinafter, a case where the detected operation state of the internal combustion engine 1 is the rotation speed and the generated torque will be described as an example. Further, instead of the injection amount from the fuel injection means 31, the generated torque of the internal combustion engine 1 may be obtained using the accelerator depression amount detection means 24 (corresponding to the operating state detection means).

  In step S15, the control device 40 obtains the belt wear amount based on the operating state of the internal combustion engine obtained in step S10, obtains the cumulative wear amount from the obtained wear amount, and proceeds to step S20. For example, the control device 40 stores the operating state / belt wear amount characteristics shown in FIG. In this operating state / wear amount characteristic, the operating state is the rotational speed and generated torque of the internal combustion engine set on the horizontal axis, and the belt wear amount set on the vertical axis depends on the rotational speed and generated torque. Determined. In general, the amount of belt wear is large due to the influence of fluctuations in engine speed, etc., at low rotation and high load (high torque). The control device 40 can calculate the belt wear amount from the rotation speed, the generated torque, and the operating state / belt wear amount characteristic. For example, the control device 40 can calculate the accumulated wear amount by integrating the calculated wear amount every predetermined time or for each [belt noise suppression main process].

  In step S20, the control device 40 obtains the friction coefficient of the belt based on the accumulated wear amount, and proceeds to step S25. For example, the control device 40 stores the accumulated wear amount / belt friction coefficient characteristics shown in FIG. The control device 40 can calculate the friction coefficient of the belt from the accumulated wear amount and the accumulated wear amount / belt friction coefficient characteristics.

  In step S25, the control device 40 obtains the belt slip speed (corresponding to the slip amount) based on the friction coefficient of the belt and the operating state of the internal combustion engine, and proceeds to step S30. For example, the control device 40 stores the driving state and belt slip speed characteristics shown in FIG. The driving state / belt slip speed characteristic is prepared for each friction coefficient, and the control device 40 extracts the driving state / belt slip speed characteristic according to the friction coefficient. In this operating state / belt slip speed characteristic, the operating state is the rotational speed and generated torque of the internal combustion engine set on the horizontal axis, and the belt slip speed set on the vertical axis is the rotational speed and generated torque. It depends on. In general, when the rotation is low and the load is high (high torque), the belt slip speed is large due to the influence of fluctuations in the engine speed and the like. The control device 40 determines the slip amount of the belt (in this case, the slip speed, based on the rotation speed, the generated torque, and the extracted operating state / belt slip speed characteristics. In the following, the “slip amount” indicates the “slip speed”. ) Can be calculated.

  In step S30, the control device 40 determines whether or not the calculated slip amount of the belt is equal to or greater than the predetermined slip amount. If the slip amount is equal to or greater than the predetermined slip amount (Yes), it is predicted that stick slip will occur. Then, the process proceeds to step S35, and when the slip amount is less than the predetermined slip amount (No), it is predicted that stick slip does not occur, and the process proceeds to step S50C. In addition, since the driving state / belt slip speed characteristic is prepared for each friction coefficient, the predetermined slip amount, which is a threshold for determination, may be changed for each friction coefficient.

  When the process proceeds to step S35, the control device 40 determines that the belt slip amount is less than the predetermined slip amount at the current rotational speed based on the operation state / belt slip speed characteristic extracted at step S30 and the current rotational speed. The generated torque is calculated and the process proceeds to step S40 (if the generated torque is reduced, the amount of slip of the belt is reduced). Note that, although there are a plurality of values for the generated torque for making the belt slip amount less than the predetermined slip amount at the current rotational speed, the highest generated torque is extracted from them.

  In step S40, the control device 40 determines whether or not the generated torque calculated in step S35 is equal to or greater than the predetermined torque. If the generated torque is equal to or greater than the predetermined torque (Yes), the control device 40 proceeds to step S45 and is less than the predetermined torque. In the case (No), the process proceeds to step S50B. When the generated torque is reduced to suppress the step stick slip, if the generated torque after the reduction becomes very small, there is a possibility that the internal combustion engine cannot be controlled appropriately. Warning (notification). In addition, since the driving state / belt slip speed characteristic is prepared for each friction coefficient, the predetermined torque, which is a threshold for determination, may be changed for each friction coefficient.

  When the process proceeds to step S50B, the control device 40 sets the torque reduction flag to OFF, gives up the stick-slip suppression control by torque reduction, turns on the warning lamp (corresponding to the warning means), and ends the process. To do. The user can know from the occurrence of stick-slip and lighting of the warning lamp that the belt has reached the end of its life and should be replaced.

  When the process proceeds to step S45, the control device 40 calculates a fuel decrease corresponding to the reduction amount of the generated torque necessary to suppress the occurrence of stick-slip, and then proceeds to step S50A. The reduced amount calculated in step S45 is used in step S120 described later.

  In step S50A, the control device 40 sets the torque reduction flag to ON, turns off the warning lamp (extinguishes), and ends the process. Reduction of the generated torque is performed by reducing the amount of fuel when fuel is injected from the control device 40 using the fuel injection means 31. This reduction in the fuel amount is carried out in a “fuel injection amount calculation process” to be described later.

  When the process proceeds to step S50C, the control device 40 sets the torque reduction flag to OFF, turns off the warning lamp, and ends the process. In this case, since it is predicted that stick-slip will not occur, the control device 40 ends the process without doing anything.

[Fuel injection amount calculation process of the first embodiment (FIG. 3)]
Next, an example of the processing procedure of [fuel injection amount calculation processing] in FIG. 3 will be described. When the execution of [fuel injection amount calculation processing] is started, the control device 40 calculates the fuel injection amount in step S110, which is the existing fuel injection amount calculation processing, and proceeds to step S115. In addition, description is abbreviate | omitted about the detail of the existing fuel injection amount calculation process of step S110.

  In step S115, the control device 40 determines whether or not the torque reduction flag is ON. If the torque reduction flag is ON (Yes), the process proceeds to step S120, and if the torque reduction flag is not ON (No) ) Terminates the process and does not reduce the fuel injection amount. Then, when the process proceeds to step S120, the control device 40 newly calculates a fuel amount obtained by subtracting the reduced amount obtained in step S45 from the fuel injection amount obtained in the existing fuel injection amount calculation process in step S110, for example. The processing is terminated as a correct fuel injection amount.

[Processing procedure for suppressing stick slip of belt 18 (second embodiment) (FIG. 7)]
Next, the processing procedure of the control device 40 in the second embodiment will be described using the flowchart shown in FIG. In the processing procedure of the second embodiment, the processing after step S25 of [Belt abnormal noise suppression main processing] of the first embodiment shown in FIG. 3 is different. Note that [fuel injection amount calculation processing] is the same and will not be described. Note that steps S10 to S20 in the flowchart shown in FIG. 7 are the same as those in the first embodiment shown in FIG. The flowchart shown in FIG. 7 is different in that steps S25 to S45 in the flowchart shown in FIG. 3 are changed to steps S32 and S47, and step S50B is omitted. Hereinafter, differences from the flowchart of the first embodiment shown in FIG. 3 will be mainly described.

  In step S32, the control device 40 determines whether or not the obtained friction coefficient is equal to or greater than the predetermined friction coefficient, and if it is equal to or greater than the predetermined friction coefficient (Yes), the controller 40 predicts that stick slip will occur and proceeds to step S47. If it is less than the predetermined friction coefficient (No), it is predicted that no stick slip will occur, and the process proceeds to step S50C.

  When it progresses to step S47, the control apparatus 40 calculates the amount of fuel reduction, and progresses to step S50A. For example, the control device 40 calculates the fuel decrease amount from the rotation speed and the friction coefficient, calculates the fuel decrease amount from the friction coefficient, or decreases the fuel injection amount by a predetermined percentage, thereby reducing the fuel amount. Calculate the weight loss. Moreover, since the process of step S50A, 50C is the same as 1st Embodiment, description is abbreviate | omitted.

  In the first embodiment shown in FIG. 3, after obtaining the friction coefficient of the belt in step S20, the slip amount of the belt is obtained in steps S25 and S30 to predict the occurrence of stick slip. In the second embodiment shown, stick slip is predicted to occur when the friction coefficient of the belt is estimated to be greater than or equal to a predetermined friction coefficient, and the generated torque is reduced by reducing the fuel injection amount by a predetermined amount. Yes. In the description of the first and second embodiments, the generated amount of fuel is reduced by reducing the fuel injection amount. However, in the case of a gasoline engine vehicle, the ignition timing is changed. The generated torque may be reduced by changing the value.

  The control device for an internal combustion engine of the present invention is not limited to the input / output and processing procedure described in the present embodiment, and various changes, additions and deletions can be made without changing the gist of the present invention. .

  In the description of the present embodiment, the diesel engine of the vehicle has been described as an example of the internal combustion engine. However, the present invention can be applied to various internal combustion engines such as a gasoline engine of a vehicle and a diesel engine of an industrial vehicle.

  In the description of the present embodiment, it is obtained from the rotational speed based on the detection signal of the operating state detecting means (crank rotation angle detecting means), the control state of the internal combustion engine (fuel injection amount) and the rotational speed by the control device. The operating state of the internal combustion engine is detected based on the generated torque. However, the generated torque may be directly detected by providing torque detecting means on the crankshaft. That is, based on the detection signal from the operation state detection means, or based on the control state of the internal combustion engine by itself (control device) and the detection signal (from the operation state detection means), the control device 40 determines the internal combustion engine. The driving state may be detected.

  Further, the above (≧), the following (≦), the greater (>), the less (<), etc. may or may not include an equal sign.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 11 Crank pulley 12 Tension adjustment pulley 13 Alternator pulley 14 Water pump pulley 15 Power steering pulley 16 Air conditioner pulley 18 Belt 21 Intake air amount detection means 22 Crank rotation angle detection means 23 Cam rotation angle detection means 24 Accelerator depression amount detection means 25 Water temperature detection means 31 Fuel injection means 32 Warning means 40 Control device

Claims (4)

A control device for an internal combustion engine that suppresses abnormal noise generated from a belt that transmits the rotational driving force of the internal combustion engine to surrounding devices,
An operating state detecting means capable of detecting the operating state of the internal combustion engine;
The controller is
Based on a detection signal from the operating state detection means or based on a control state of the internal combustion engine by itself and the detection signal, the operating state of the internal combustion engine is detected,
Based on the detected operating state, estimate the amount of wear of the belt,
Find the cumulative wear amount by integrating the estimated wear amount,
Based on the obtained cumulative wear amount, the friction coefficient of the belt is obtained,
According to the determined coefficient of friction, the operating state of the internal combustion engine is changed.
Control device for internal combustion engine. A control device for an internal combustion engine according to claim 1,
The controller is
Based on the determined coefficient of friction and the operating state of the internal combustion engine, the amount of slip of the belt is determined,
When the determined slip amount is equal to or greater than a predetermined slip amount, it is determined that abnormal noise is generated from the belt, and the generated torque of the internal combustion engine is reduced so that the slip amount is less than the predetermined slip amount. Changing the operating state of the internal combustion engine,
Control device for internal combustion engine. A control device for an internal combustion engine according to claim 2,
The controller is
Reducing the amount of fuel supplied to the internal combustion engine when reducing the torque generated by the internal combustion engine;
Control device for internal combustion engine. A control device for an internal combustion engine according to claim 2 or 3,
The controller is
When the generated torque of the internal combustion engine is reduced, if it is determined that the generated torque that has been reduced so that the slip amount is less than the predetermined slip amount is less than the predetermined torque, the warning means is operated to notify,
Control device for internal combustion engine.

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