JP5057099B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine.

Conventionally, in a vehicle equipped with an engine having a fuel cut means that temporarily cuts the fuel supply to the engine when the vehicle is in a predetermined deceleration operation state, the engine torque rapidly increases when the fuel cut is resumed. Shock may occur. In order to suppress this, for example, in Patent Document 1, as the total load torque corresponding to the detected engine speed is larger, the retard amount of ignition timing and the time for retarding are controlled to suppress the engine output. A control device is described.
Japanese Patent Laid-Open No. 2-40055 (Claim 2, FIG. 1, etc.)

  As described above, the control device described in Patent Document 1 simply detects the engine speed when the fuel cut is restored, and attempts to suppress the engine output as the full load torque corresponding to the engine speed increases. Is. Therefore, in Patent Document 1, no consideration is given to accurately setting a target torque value that is a target value for suppressing engine output. For this reason, even if ignition control is performed to suppress engine output, it is not possible to make a detailed setting of the retard amount and the time for performing the retard. As a result, the control device cannot appropriately suppress the engine output, and it is difficult to say that the torque shock can be effectively suppressed.

  By the way, in order to set the control target value of the vehicle such as the target torque value with high accuracy, generally, many target values (data) corresponding to the respective driving conditions of the vehicle are required. In this case, there is a problem that as the number of data points increases, the calculation becomes complicated and the calculation load increases. On the other hand, when the control target value is set based on a small amount of data, for example, as described in Patent Document 1, when the target torque value is set by simply mapping the full load torque based on the engine speed, As described above, there is a problem that the setting accuracy of the target torque value is lowered, and effective suppression of torque shock cannot be realized. Under such circumstances, there is a demand for a method that can set the target torque value with higher accuracy without causing a significant increase in calculation load.

  The torque shock as described above is a problem that occurs not only when the fuel cut is restored, but also when the engine torque suddenly increases during acceleration or shifting. Therefore, the method for setting the target torque value is also required to be highly versatile.

  Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and a target torque value can be set with higher accuracy with a simple configuration, and as a result, an internal combustion engine that can more effectively suppress torque shock. An engine control device is provided.

The control apparatus for an internal combustion engine according to the present invention includes a required torque value setting means for setting a required torque value according to a driver's request, and a first target torque different from the required torque value according to a predetermined driving state of the vehicle. First target torque value setting means for setting a value, second target torque value setting means for setting a second target torque value based on the required torque value and the first target torque value, and the second target torque value Control means for controlling the internal combustion engine in accordance with the first target torque value setting means, wherein the first target torque value setting means sets a first torque value by adding a predetermined gain value to the previously set first target torque value. First torque value setting means; and second torque value setting means for setting a second torque value by performing a first-order lag filter process using the required torque value as an input based on the first target torque value set previously. Comprising The first torque value is set as the first target torque value during the first predetermined period after both have entered the predetermined operating state, and the first predetermined period after the first predetermined period has elapsed, A torque value is set as the first target torque value .

  In the present invention, the first target torque value setting means sets the first target torque value according to the predetermined driving state of the vehicle, and the second target torque value setting means sets the required torque value and the first target torque value. Based on this, a second target torque value is set. Thereby, it is possible to set the second target torque value with high accuracy so that the torque shock can be effectively suppressed with a simple configuration. In the present invention, the driving state of the vehicle includes an increasing state of the engine torque at the time of fuel cut return, acceleration, shift, and the like.

Also , the first torque value obtained by adding the second torque value subjected to the first-order lag filter processing and the tailing gain value is set, and the first target torque value is set based on the set first torque value and second torque value. That is, since only the two values are set to set the first target torque value, the calculation load is small. In addition, since the setting is based on these two values, the first target torque value can be set with high accuracy.

In addition , since the second torque value subjected to the first-order lag filtering process can be set as the first target torque value for the first predetermined period after the vehicle is in a predetermined driving state, the acceleration feeling that follows the increase in the required torque value. It is possible to easily set the second target torque value that does not impair the torque. Furthermore, since the first torque value that gradually changes can be set as the first target torque value in the next predetermined period after the predetermined period has elapsed, the second target torque value that follows the increase in the required torque value can be set earlier. Can do. Note that the first predetermined period here means at least the first predetermined period after the vehicle enters a predetermined driving state. Therefore, the second torque value is set as the first target torque value in the first predetermined period after the vehicle enters the predetermined driving state, the first torque value is set as the first target torque value in the next predetermined period, Thereafter, the second torque value may be set again as the first target torque value in the next predetermined period.

  In this case, the first target torque value setting means sets a period in which the second torque value is larger than the first torque value as the first predetermined period, and the second torque is set in the predetermined period. A value is set as the first target torque value, a period in which the first torque value is greater than the second torque value is set as the next predetermined period, and the first torque value is set in the predetermined period during the predetermined period. It is preferable to set as one target torque value. Thus, by setting the first predetermined period and the next predetermined period depending on the magnitude of the first torque value and the second torque value, it is possible to set the target torque value very easily.

  Further, it is preferable that the second target torque setting means sets the smaller value as the second target torque value by comparing the required torque value and the first target torque value. By setting the smaller of the required torque value and the first target torque value as the second target torque value, when the first target torque value exceeds the required torque value, the required torque value is set as the second target torque value. Can be set. As a result, the internal combustion engine can be controlled more appropriately.

  Fuel cutting means for temporarily cutting the supply of fuel to the internal combustion engine is further provided. In this case, the predetermined operation state is a fuel cut return state, and the vehicle is in an acceleration operation state. Furthermore, it is preferable that the vehicle is in a shift state. The torque shock can be suppressed by setting the target torque at the time of fuel cut recovery, acceleration operation, and shift.

  According to the control apparatus for an internal combustion engine of the present invention, the second target torque value for controlling the internal combustion engine can be set with higher accuracy by a simple configuration that does not cause a significant increase in the calculation load. It is possible to achieve an excellent effect that can be effectively suppressed. Furthermore, according to the present invention, the target torque value can be set more easily and accurately in response to various operating conditions in which torque shock is likely to occur, so that the effect of extremely high versatility can be achieved.

  A control apparatus for an internal combustion engine according to the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram showing a configuration of an internal combustion engine (engine) system.

  A gasoline engine (hereinafter simply referred to as an engine) 11 shown in FIG. 1 is an intake pipe injection type (Multi Point Injection) gasoline engine. The engine 11 has a cylinder head 12 and a cylinder block 13. A piston 15 is accommodated in each cylinder 14 of the cylinder block 13 so as to be reciprocally movable. The piston 15, the cylinder 14, and the cylinder head 12 form a combustion chamber 16. The piston 15 is connected to the crankshaft 18 via a connecting rod 17. The reciprocating motion of the piston 15 is transmitted to the crankshaft 18 via the connecting rod 17.

  An intake port 19 is formed in the cylinder head 12. An intake manifold 20 is connected to the intake port 19. An intake pipe 21 is connected to the intake manifold 20. An intake valve 22 is provided in the intake port 19. The intake port 19 is opened and closed according to the opening degree of the intake valve 22. Further, the intake manifold 20 is provided with a fuel injection valve 23. A fuel supply device (not shown) having a fuel tank is connected to the fuel injection valve 23 via a fuel valve.

  An exhaust port 24 is further formed in the cylinder head 12. One end of an exhaust manifold 25 is connected to the exhaust port 24. An exhaust pipe 26 is connected to the other end of the exhaust manifold 25. The exhaust port 24 is provided with an exhaust valve 27. Like the intake valve 22 in the intake port 19, the exhaust port 24 is opened and closed by the exhaust valve 27.

  A spark plug 28 is attached to the cylinder head 12 for each cylinder. Each ignition plug 28 is connected to an ignition coil 29 that outputs a high voltage. The intake pipe 21 on the upstream side of the intake manifold 20 is provided with a throttle valve 31 that adjusts the intake air amount and a throttle position sensor (TPS) 32 that detects the valve opening of the throttle valve 31. Further, an intake air amount sensor (air flow sensor) 33 for measuring the intake air amount is provided upstream of the throttle valve 31.

A three-way catalyst 34 that is an exhaust purification catalyst is interposed in the exhaust pipe 26 connected to the exhaust manifold 25. An O ₂ sensor 35 for detecting the oxygen concentration in the exhaust gas before passing through the catalyst is provided on the upstream side of the three-way catalyst 34.

The ECU (electronic control unit) 36 includes an input / output device, a storage device (ROM, RAM, etc.), a central processing unit (CPU), a timer counter, and the like. The ECU 36 performs comprehensive control of the control device 10 including the engine 11. Various sensors such as an accelerator position sensor 38 for detecting the opening degree of the accelerator pedal 37 are connected to the input side of the ECU 36 in addition to the TPS 32, the intake air sensor 33 and the O ₂ sensor 35 described above. Detection information from a class is input.

  On the other hand, various output devices such as the fuel injection valve 23, the ignition coil 29, and the throttle valve 31 are connected to the output side of the ECU 36. These various output devices output the fuel injection time, ignition timing, throttle opening, and the like calculated by the ECU 36 based on detection information from various sensors.

  The control device 10 includes the ECU 36 and the various sensors described above. Based on detection information from the various sensors, an appropriate amount of fuel is injected from the fuel injection valve 23 at an appropriate timing, and the throttle valve 31 is The opening degree is adjusted to an appropriate degree, and spark ignition is performed by the spark plug 28 at an appropriate ignition timing.

  Further, in the present embodiment, the ECU 36 includes target torque value setting means (first and second target torque value setting means) 40 and required torque value setting means 41. The target torque value setting means 40 accurately sets the target torque value T (second target torque value) based on detection information from various sensors. Since the ECU 36 has the target torque value setting means 40, the throttle opening, the ignition timing, and the fuel injection amount can be appropriately set based on the target torque value T, and drivability can be improved.

  Hereinafter, the target torque value setting means 40 and the required torque value setting means 41 will be described in detail.

  The required torque value setting means 41 is for setting the required torque value Td in response to the driver's request. The required torque value setting means 41 is configured to receive detection information indicating the opening degree of the accelerator pedal 37 from the accelerator position sensor 38. That is, the required torque value setting means 41 sets the amount of acceleration requested by the driver as the required torque value Td according to the detection information detected as the operation opening of the accelerator pedal 37.

  The target torque value setting means 40 is configured to set the target torque value T according to the required torque value Td when the vehicle is in a predetermined driving state. In the present embodiment, by having the target torque value setting means 40, by setting the target torque value T according to the driver's request, the control that can effectively suppress the torque shock with a simple configuration and with high accuracy. Is possible.

  Here, the target torque value T set by the target torque value setting means 40 is set so that it can quickly approach the torque value required by the driver according to the driving state of the vehicle while suppressing torque shock. Yes. The target torque value setting means 40 is configured such that the target torque value T is set to be equal to or less than the required torque value Td.

  In addition, the case where the vehicle is in a predetermined driving state refers to a case where the engine torque of the vehicle suddenly increases when returning from fuel cut, acceleration operation, or gear shifting. In these cases, if the torque is suddenly increased according to the driver's request, a torque shock may occur. Therefore, in the present embodiment, an appropriate target torque value T is set by the target torque value setting means 40. .

  In order to set the target torque value T as described above, the target torque value setting means 40 includes a first torque value setting means 42 that calculates a first torque value T1 by adding a predetermined gain value, and a required torque. Second torque value setting means 43 for calculating a second torque value T2 by performing first-order lag filtering on the value Td. The target torque value setting means 40 is configured to set the target torque value T based on the first torque value T1 and the second torque value T2.

  Specifically, the target torque value setting means 40 sets the second torque value T2 as the target torque value T for the first predetermined period after the vehicle enters a predetermined driving state, and the next after the first predetermined period has elapsed. During the predetermined period, the first torque value T1 is set as the target torque value T.

  The reason for this configuration is as follows. That is, when the required torque value Td suddenly increases, it is not possible to obtain an acceleration feeling only by gradually increasing the target torque value T by only performing gain value addition processing. Therefore, in the present embodiment, the second torque value T2 calculated by the first-order lag filter process that easily follows the rapid increase in the required torque value Td for the first predetermined period after the vehicle enters the predetermined driving state is set as the target. The torque value T is set. On the other hand, if only the first-order lag filtering process is performed, the rate of change gradually decreases with the passage of time, and it takes time to reach the required torque value Td, and the feeling of acceleration is impaired.

  Therefore, in the present embodiment, the first torque value T1 calculated by the addition process of adding the gain value is set as the target torque value T for the next predetermined period after the elapse of the predetermined period. Therefore, in the present embodiment, as described above, the second torque value T2 is set as the target torque value T for the first predetermined period after the vehicle enters the predetermined driving state, and the next predetermined period after the predetermined period has elapsed. The target torque value setting means 40 is configured to set the first torque value T1 as the target torque value T.

  Here, the first predetermined period will be described. In the present embodiment, a period in which the second torque value T2 is greater than the first torque value T1 is set as the first predetermined period. Further, a period in which the first torque value T1 is larger than the second torque value T2 is set as the next predetermined period after the first predetermined period. In other words, the target torque value setting means 40 sets a period during which the second torque value T2 is greater than the first torque value T1 after the vehicle is in a predetermined driving state as the first predetermined period. After the torque value T1 becomes larger than the second torque value T2, it is set as the next predetermined period after the first predetermined period. Note that the first predetermined period refers to at least the first predetermined period after the vehicle enters a predetermined driving state.

  By setting the first predetermined period and the next predetermined period in this way, it is possible to perform control having the two advantages described above. That is, during a period when the second torque value T2 is large after the vehicle enters a predetermined driving state (period in which the rate of change of the second torque value is greater than the rate of change of the first torque value T1), the second torque value T2 is set. The target torque value T is set so that control can easily follow the sudden increase in the required torque value Td. On the other hand, during a period in which the first torque value T1 is large (a period in which the rate of change of the first torque value T1 is greater than the rate of change of the second torque value T2), the first torque value T1 is set as the target torque value T. As a result, it is possible to perform control that does not take much time until it substantially matches the required torque value Td and does not impair the feeling of acceleration. Further, if the first predetermined period and the next predetermined period are set according to the magnitude of the first torque value T1 and the second torque value T2, the first torque value T1 and the second torque value T2 can be easily selected. As a result, the target torque value T can be set easily and accurately.

  As described above, in this embodiment, the target torque value T can be set only by simple processing such as first-order lag processing and gain value addition processing. In particular, the first-order lag filtering process has the advantage that it is easy to follow even when the required torque value Td changes during control, and the drivability is good. Further, in the present embodiment, the target torque value setting means 40 sets the second torque value T2 set as the target torque value T for a predetermined period after entering a predetermined operation state, and after the predetermined period has elapsed, The set first torque value T1 is set as the target torque value T. This has the advantage of using these first-order lag filter processing and gain processing, and excludes the disadvantages of using only the first-order lag filter processing and gain processing.

  Further, when the target torque value T is set, the target torque value T needs to be equal to or less than the required torque value Td. Therefore, when the target torque value T is set, the target torque value setting means 40 sets the larger one of the first torque value T1 and the second torque value T2 as a temporary target torque value (first target torque value) Tv. The temporary target torque value Tv and the required torque value Td are compared, and the smaller value is set as the target torque value T.

  Hereinafter, setting of the target torque value will be described with reference to FIG. FIG. 2 is a flowchart for explaining a process of setting a target torque value.

  When the control is started, in step S1, the requested torque value setting means 41 sets the requested torque value Td of the driver based on the detection information indicating the opening degree of the accelerator pedal 37 detected by the accelerator position sensor 38. After this setting, the process proceeds to step S2.

  In step S2, it is determined whether or not the vehicle is in a predetermined driving state. In the present embodiment, as an example, it is determined whether or not the fuel cut is restored. Specifically, whether or not the fuel cut is restored depending on whether or not the injection pulse of the fuel injection valve 23 at t = n (n is the number of steps) is positive and the injection pulse at t = n−1 is 0. Judging. If it is not when the fuel cut is restored (NO), the process proceeds to step S3, and a constant m is input to the variable m.

  On the other hand, if it is time to return to fuel cut (YES), the process proceeds to step S4, and a constant n is input to the variable m.

  After step S3 or step S4, the process proceeds to step S5. In step S5, the value of the variable m obtained in steps S3 and S4 is substituted into the equation t− (m + α). Here, α indicates a predetermined value, which is the sum of the first number of combustions in each cylinder (that is, the sum of the number of combustions for two engine revolutions, for example, 4 for four cylinders), and fuel cut recovery Otherwise, it is 0. T is a variable representing the number of steps. Therefore, for example, when t = n and after the fuel cut is restored, since t = n and m = n are input to the above equation, the equation becomes −α, which is a negative value. In general, the case where the value of this equation does not become positive (a negative value and 0) is not after the fuel cut is restored, and when the predetermined number of steps is passed after the fuel cut is restored.

  On the other hand, the case where the value of this equation becomes positive means that t = n + α + 1 or more, that is, the case where a predetermined number of steps, that is, the number of steps corresponding to the number of combustion passes after the return from fuel cut. This is because the fuel for the first time in each cylinder after returning to the fuel cut is not burning because the fuel cut is in front of it, and no residual gas remains in the cylinder. This is because torque shock may occur when the target torque value is set from the torque value.

  In step S5, if the value of the expression t− (m + α) is negative (NO), the process proceeds to step S6, and the target torque value setting means sets the temporary target torque value Tv to the limited torque value TL. To do. On the other hand, if the value is positive (YES), the process proceeds to step S7 and subsequent steps. In step S7, a first torque value T1 is set. Specifically, the first torque value T1 is calculated by adding the tailing gain value to the previously set temporary target torque value Tv.

  Next, the process proceeds to step S8, where a first-order lag filter process is performed on the required torque value Td to set a second torque value T2. Specifically, the second torque value is obtained by adding the value obtained by subtracting the predetermined value K from 1 to the required torque value Td to the value obtained by multiplying the previously set temporary target torque value Tv by the predetermined value K. T2 is calculated (Tv × K + (1−K) × Td). As described above, in the present embodiment, the target torque value T can be set by simple processing such as addition processing and first-order lag filtering processing.

  Next, the process proceeds to step S9, and it is compared which of the first torque value T1 and the second torque value T2 is greater. When the second torque value T2 is larger than the first torque value T1 (NO), the process proceeds to step S10, and the second torque value T2 is set as the temporary target torque value Tv. When the first torque value T1 is larger than the second torque value T2 (YES), the process proceeds to step S11, and the first torque value T1 is set as the temporary target torque value Tv.

  After going through any of the above steps S6, S10 and S11, the process proceeds to step S12. In step S12, it is determined whether the required torque value Td is larger than the temporary target torque value Tv. When the required torque value Td is smaller than the temporary target torque value Tv (NO), the process proceeds to step S13, and the required torque value Td is set as the target torque value T. When the required torque value Td is larger than the temporary target torque value Tv (YES), the process proceeds to step S14, and the temporary target torque value Tv is set as the target torque value T. Thus, in the present embodiment, the target torque value T is configured not to be set larger than the required torque value Td.

  As described above, the target torque value T can be set with a simple configuration in the engine control apparatus 10 of the present embodiment. In this case, the obtained target torque value T is, for example, as shown in FIG. FIG. 3 is a graph for explaining the target torque value.

  The requested torque value Td, which is the torque value requested by the driver, is constant at Tq1 after the vehicle enters a predetermined operating state at time t = t1 and the torque rises to Tq1. The target torque value T rises in a gentle curve until t1 ≦ t <t2. That is, t1 ≦ t <t2 is a predetermined period in which the second torque value T2 is larger than the first torque value T1, and the second torque value T2 is set as the target torque value Tv. And in t2 <= t <t3, the target torque value T is increasing gradually. That is, t2 ≦ t <t3 is after a predetermined period when the first torque value T1 is greater than the second torque value T2, and the first torque value T1 is set as the temporary target torque value Tv. Then, at t3 ≦ t, the required torque value Td is set as the target torque value T.

  Thus, when the required torque value Td increases rapidly, the second torque value T2 that is initially subjected to the first-order lag filtering process is set as the target torque value T, so that the acceleration feeling is not impaired. . And since the 1st torque value T1 which added the gain value after that is set as the target torque value T, the target torque value T can increase smoothly and can correspond to the request | required torque value Td. Since the engine is controlled according to the set target torque value T, the engine according to the present embodiment does not impair the acceleration feeling while suppressing the torque shock, thereby effectively reducing the drivability of the vehicle. Can be prevented.

  In the present embodiment, the target torque value setting means 40 adds a predetermined gain value to the required torque value Td in order to easily set the torque value in setting the target torque value by the target torque value setting means 40. The first torque value setting means 42 for setting the first torque value T1 and the second torque value setting means 43 for setting the second torque value T2 by performing the first-order lag filter processing are provided. As long as the target torque value that does not impair acceleration feeling while suppressing the torque shock as shown in FIG. 3 can be set, other processing may be used.

  Further, since the first predetermined period is at least the first predetermined period after the vehicle enters the predetermined driving state, the second torque value T2 is temporarily set during the first predetermined period after the vehicle enters the predetermined driving state. The first torque value T1 is set as the temporary target torque value Tv for the next predetermined period, and then the second torque value T2 is again set as the temporary target torque value Tv for the next predetermined period. A case where setting is repeated is also included in the present embodiment.

  In the present embodiment, the target torque value setting means 40 and the required torque value setting means 41 are different from each other, but the target torque value setting means 40 is configured to include the required torque value setting means 41. Is also possible. Furthermore, in the present embodiment, the target torque value setting means 40 includes the first torque value setting means 42 and the second torque value setting means 43, but these are configured as means different from the target torque value setting means 40. May be.

  In the present embodiment, the target torque is set when the fuel cut is restored. However, the present invention is not limited to when the fuel cut is restored, and the engine torque changes suddenly during a transient operation of the vehicle, a shift of the vehicle, or the like. Can be used in some cases.

  The control apparatus for an internal combustion engine of the present invention can be used in, for example, the automobile manufacturing industry.

It is a mimetic diagram showing composition of an engine system of this embodiment. It is a flowchart for demonstrating the action | operation of the engine system of this embodiment. It is a graph for demonstrating the target torque value by the engine system of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Control apparatus 11 Engine 37 Accelerator pedal 38 Accelerator position sensor 40 Target torque value setting means 41 Request torque value setting means 42 First torque value setting means 43 Second torque value setting means

Claims (6)

Requested torque value setting means for setting a requested torque value according to a driver's request;
First target torque value setting means for setting a first target torque value different from the required torque value according to a predetermined driving state of the vehicle;
Second target torque value setting means for setting a second target torque value based on the required torque value and the first target torque value;
Control means for controlling the internal combustion engine in accordance with the second target torque value ,
The first target torque value setting means includes
First torque value setting means for setting a first torque value by adding a predetermined gain value to the previously set first target torque value;
A second torque value setting means for setting a second torque value by performing a first-order lag filtering process using the requested torque value as an input based on the first target torque value set last time;
In the first predetermined period after the vehicle enters the predetermined driving state, the second torque value is set as the first target torque value,
The control apparatus for an internal combustion engine, wherein the first torque value is set as the first target torque value in a next predetermined period after the first predetermined period has elapsed . The first target torque value setting means includes
A period in which the second torque value is larger than the first torque value is set as the first predetermined period, and in the predetermined period, the second torque value is set as the first target torque value,
A period in which the first torque value is larger than the second torque value is set as the next predetermined period, and the first torque value is set as the first target torque value in the predetermined period. The control apparatus for an internal combustion engine according to claim 1 . The said 2nd target torque setting means compares the said request | required torque value and said 1st target torque value, and sets a small value as said 2nd target torque value, The Claim 1 or 2 characterized by the above-mentioned. Control device for internal combustion engine. A fuel cutting means for temporarily cutting the supply of fuel to the internal combustion engine;
The predetermined operating condition, the control device for an internal combustion engine according to any one of claims 1 to 3, characterized in that a fuel cut recovery state. The control apparatus for an internal combustion engine according to any one of claims 1 to 3 , wherein the predetermined operation state is an acceleration operation state of the vehicle. The predetermined operating condition, the control device for an internal combustion engine according to any one of claims 1 to 3, characterized in that a shifting state of the vehicle.

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