JP2013217255A - Internal combustion engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain such a pulse-like torque change in a torque-up direction that is required in shift-down of an electronically-controlled automatic transmission, in a torque-demand control type control device that cooperatively operates an actuator for changing an air amount and an ignition device based on request torque for an internal combustion engine.SOLUTION: An operation amount of an actuator is determined based on request torque, and ignition timing required to achieve the request torque based on the current air amount and the request torque is calculated. However, if the request torque contains a pulse component in a torque-up direction, an ignition retard amount relating to final ignition timing is restricted with respect to a retard amount required to achieve the request torque, during at least a specific period after the pulse component.

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly, to a torque demand control type control device that cooperatively operates an actuator for changing an air amount and an ignition device based on a required torque for the internal combustion engine.

  As a control device for an internal combustion engine, for example, a torque demand control type control device as disclosed in Patent Documents 1 and 2 below is known. This conventional apparatus calculates the target throttle opening based on the required torque, and calculates the ignition timing required to achieve the required torque based on the current air amount. More specifically, the torque obtained if the ignition timing is set to the optimal ignition timing under the current air amount is estimated, and the retard amount of the ignition timing is calculated according to the ratio of the required torque to the estimated torque. . According to the conventional apparatus, the torque actually generated by the internal combustion engine can be changed following the required torque.

JP 2011-252425 A JP 2011-185122 A

  By the way, the required torque for the internal combustion engine includes requests from various control devices such as a traction control system, a vehicle stability control system, or an electronically controlled automatic transmission, in addition to the driver required torque calculated from the accelerator pedal opening. Torque is also included. Among these, the electronically controlled automatic transmission requires a pulsed torque in the torque-up direction at the time of the downshift.

  According to the above conventional apparatus, when the required torque changes, the throttle opening is immediately changed accordingly. However, since there is a response delay between the change in the throttle opening and the change in the amount of air in the cylinder, there is a time axis deviation between the estimated torque calculated from the current amount of air and the required torque. Will occur. For this reason, as shown in FIG. 5, when the required torque changes in a pulse-like manner in the torque-up direction, the change in the estimated torque is not in time for the change in the required torque, and the required torque is increased while the estimated torque is increasing. Will return to the original level.

  At this time, if the estimated torque becomes the output torque of the internal combustion engine as it is, a pulse-like torque change as required can be realized with some time delay. However, according to the conventional device, when the estimated torque is larger than the required torque, the ignition timing is automatically retarded so as to cancel the surplus of the estimated torque with respect to the required torque. For this reason, the conventional apparatus cannot realize the pulse-like torque change required from the electronically controlled automatic transmission as required.

  The present invention has been made in view of the above-described problems. For example, a torque demand capable of realizing a pulse-like torque change in a torque-up direction as required when shifting down an electronically controlled automatic transmission. An object of the present invention is to provide a control type control device.

  In order to achieve the above object, a control apparatus for an internal combustion engine according to the present invention is configured to perform the following operations.

  The control device according to the present invention determines the operation amount of the actuator that changes the air amount based on the required torque for the internal combustion engine, and is necessary for achieving the required torque based on the current air amount and the required torque. Calculate the ignition timing. However, if the required torque includes a pulse component in the torque-up direction, at least a predetermined period after the pulse component, the ignition delay amount related to the final ignition timing is the retardation amount necessary to achieve the required torque. Restrict against. The ignition delay amount can be limited by prohibiting the ignition timing retardation, setting a predetermined guard value for the ignition timing retardation amount, or smoothing the calculated ignition timing value. Any of the above is preferred. In particular, if retarding the ignition timing is prohibited, it is more preferable to gradually change the ignition timing toward the ignition timing necessary to achieve the required torque when canceling the prohibition of the ignition timing. Note that the current air amount used for calculating the ignition timing may be a value measured by an air flow meter, or may be calculated from an operation amount of the actuator using an air model.

  According to the control device of the present invention, since the operation amount of the actuator that changes the air amount is determined based on the required torque, when the required torque changes in a pulse shape in the torque-up direction, the air amount is delayed after that. Also, a pulse-like change occurs. Due to the delay in the response of the change in the air amount to the change in the required torque, the air amount remains high even after the required torque has decreased to the original level. According to the conventional torque demand control, when the current air amount exceeds the air amount necessary for realizing the required torque in this way, ignition is performed so that the torque increase due to the surplus is offset by the retard of the ignition timing. The amount of retardation is calculated. However, according to the control device of the present invention, the ignition delay amount related to the final ignition timing is the retardation required for achieving the required torque for a predetermined period after the required torque changes in a pulse shape in the torque-up direction. Limited to quantity. As a result, the output torque of the internal combustion engine is allowed to be excessive with respect to the required torque at least for a predetermined period. Therefore, the pulse-like torque change in the torque-up direction is realized by the above-described pulse-like air amount change. The

It is a block diagram which shows the structure of the control apparatus which concerns on embodiment of this invention. It is a flowchart which shows the routine of the ignition retard control which concerns on embodiment of this invention. It is a figure which shows the control result by the control apparatus which concerns on embodiment of this invention. It is a figure which shows the control result by the modification of the control apparatus which concerns on embodiment of this invention. It is a figure which shows the control result by a conventional apparatus.

  Embodiments of the present invention will be described with reference to the drawings.

  An internal combustion engine (hereinafter referred to as an engine) to be controlled in an embodiment of the present invention is a spark ignition type four-cycle reciprocating engine. The control device according to the present embodiment uses torque and efficiency as engine control amounts. More specifically, the term “torque” here means the indicated torque generated by the engine. The efficiency means the ratio of the torque that is actually output to the torque that the engine can potentially output (latent torque). The maximum value of efficiency is 1, and at that time, the potential torque that can be output by the engine is actually output as it is. When the efficiency is smaller than 1, the torque that is actually output is smaller than the potential torque that can be output by the engine, and the margin is mainly output as heat and output from the engine. Since the efficiency reaches the maximum value of 1 when the ignition timing is the optimal ignition timing, the efficiency can be defined as the ratio of the torque at the actual ignition timing when the torque at the optimal ignition timing is 1.

  In the embodiment of the present invention, the control device controls the operation of the engine by operating various actuators provided in the engine. In the embodiment of the present invention, the control device operates a throttle and an ignition device, and the control device operates these two actuators to control the torque output by the engine. The operation amount of the throttle by the control device is the throttle opening, and the operation amount of the ignition device is the ignition timing. The control device outputs a command value of each operation amount to the engine, that is, a throttle opening command value and an ignition timing command value.

  FIG. 1 is a block diagram showing a configuration of a control device according to an embodiment of the present invention. In the vehicle control system, a powertrain manager 10 is arranged above the control device 20 according to the present embodiment. The control device 20 and the powertrain manager 10 are realized as one function of a common or separate ECU. Specifically, the ECU stores the program stored in the memory, and the ECU functions as the control device 20 and the powertrain manager 10 according to the present embodiment, and each element shown in FIG. 1 is virtually realized. It has become so.

  The powertrain manager 10 includes a plurality of request output elements 12, 14, 16, and 18. The required output element 12 outputs a required torque (driver required torque) Tqd calculated from the opening of the accelerator pedal. The demand output element 14 outputs a pulse demand torque (ECT demand torque) Tqect in conjunction with the shift change of the electronically controlled automatic transmission. The request output elements 16 and 18 are elements for idle speed control. The required output element 16 outputs the torque required to maintain the idle speed as the required torque (ISC required torque) Tqisc, and the required output element 18 is necessary for retarding the ignition timing and securing the reserve torque. The efficiency is output as the required efficiency η0. In addition to these, the powertrain manager 10 includes a plurality of required output elements (not shown), and the required torque is also output from them.

  The control device 20 receives the required torques Tqd, Tqect, Tqisc and the required efficiency η0 output from the powertrain manager 10, and determines the throttle opening command value TA and the ignition timing command value SA for the engine based on these required values. In FIG. 1, the plurality of elements constituting the control device 20 represent only elements related to the determination of the throttle opening command value TA and the ignition timing command value SA. Therefore, FIG. 1 does not mean that the control device 20 according to the present embodiment is configured by only these elements. Specifically, the control device 20 includes a required torque arbitration unit 22, an air amount control torque calculation unit 24, a target air amount calculation unit 26, a throttle opening calculation unit 28, an estimated torque calculation unit 30, and an ignition timing control efficiency. A calculation unit 32, an ignition timing calculation unit 34, and an ignition delay control unit 36 are provided.

  First, the configuration related to the throttle opening command value TA in the control device 20 will be described. All the required torques Tqd, Tqect, Tqisc output from the powertrain manager 10 are collected in the required torque arbitration unit 22. The required torque arbitration unit 22 adjusts the collected required torques Tqd, Tqect, and Tqisc into one. Arbitration is a calculation process for obtaining one numerical value from a plurality of numerical values, for example, maximum value selection, minimum value selection, average, or superposition, and a plurality of types of calculation processes are appropriately combined. You can also. In the case of the present embodiment, at the time of shift up accompanying acceleration, the driver request torque Tqd is added to the ISC request torque Tqisc, and the pulsed ECT request torque Tqect output in conjunction with the shift up is subtracted. On the other hand, at the time of downshift accompanying deceleration, the pulsed ECT required torque Tqect is added to the ISC required torque Tqisc. Hereinafter, the request torque after arbitration by the request torque arbitration unit 22 is referred to as post-arbitration request torque Tq0.

  The requested torque Tq0 after arbitration is input to the air amount control torque calculator 24 together with the required efficiency η0 output from the powertrain manager 10. The air amount control torque calculator 24 calculates the air amount control torque Tq1 by dividing the post-arbitration request torque Tq0 by the required efficiency η0. According to the processing performed by the air amount control torque calculation unit 24, if the value of the required efficiency η0 is 1, the post-arbitration required torque Tq0 is determined as it is as the air amount control torque Tq1, and the value of the required efficiency η0 is 1. In the case where it is smaller, the air amount control torque Tq1 is determined by raising the post-arbitration required torque Tq0.

  The air amount control torque Tq1 is input to the target air amount calculation unit 26. The target air amount calculation unit 26 calculates the air amount necessary to achieve the air amount control torque Tq1. In the calculation of air, a map using arguments of torque, target air-fuel ratio, and engine speed is used. In the map, it is assumed that the ignition timing is the optimum ignition timing (the retarded ignition timing of MBT and trace knock ignition timing). The air amount obtained by the calculation is set as the target air amount KLt of the engine.

  The target air amount KLt is input to the throttle opening calculation unit 28. The throttle opening calculation unit 28 calculates the throttle opening required to achieve the target air amount KLt. An air inverse model is used to calculate the throttle opening. An air model is a physical model of the intake system in which the response of the air amount to the operation of the throttle is modeled based on fluid dynamics, and the air inverse model is the inverse model. The control device 20 operates the throttle with the throttle opening calculated using the air inverse model as the throttle opening command value TA.

  Next, a configuration related to the ignition timing command value SA in the control device 20 will be described. In parallel with the above processing, the control device 20 calculates the estimated torque Tqe based on the current air amount in the estimated torque calculator 30. In the calculation of the estimated torque, it is assumed that the ignition timing is the optimum ignition timing, and a map using the air amount, the target air-fuel ratio, and the engine speed as arguments is used. The current air amount is calculated from the actual throttle opening using the above air model.

  The estimated torque Tqe is input to the ignition timing control efficiency calculator 32. The ignition timing control efficiency calculator 32 also receives the post-arbitration required torque Tq0 that is input to the air amount control torque calculator 24. The ignition timing control efficiency calculation unit 32 calculates the ratio of the post-arbitration required torque Tq0 to the estimated torque Tqe as the ignition timing control efficiency η1.

  The ignition timing control efficiency η 1 is input to the ignition timing calculator 34. The ignition timing calculator 34 calculates the ignition timing based on the ignition timing control efficiency η1. In the calculation of the ignition timing, the base ignition timing (for example, the optimal ignition timing) is calculated based on various engine information such as the engine speed and the air amount, and the ignition timing control efficiency η1 and various engine information are used as arguments. The ignition retard amount is calculated using the map to be used. According to the map, if the value of the ignition timing control efficiency η1 is 1, the ignition delay amount is zero, and the smaller the value of the ignition timing control efficiency η1 is, the larger the ignition delay amount is. . The ignition timing obtained by adding the ignition retardation amount to the base ignition timing is the final ignition timing. However, as will be described below, the ignition timing calculation unit 34 adds the ignition delay amount to the base ignition timing only when an ignition delay flag, which will be described later, is “permitted (ON)”. When the ignition retard flag is “prohibited (off)”, the ignition timing calculation unit 34 does not retard the ignition timing and determines the base ignition timing as the final ignition timing. The control device 20 operates the ignition device with the final ignition timing as the ignition timing command value SA.

  The ignition retard control unit 36 determines whether the ignition retard flag is “permitted” or “prohibited”. The ignition retard control unit 36 receives the same driver request torque Tqd and ECT request torque Tqect as those input to the request torque arbitration unit 22. The ignition retard control unit 36 determines whether the ignition retard flag is “permitted” or “prohibited” based on the input information, and transmits the determination result to the ignition timing calculation unit 34. Hereinafter, specific processing performed by the ignition retard control unit 36 will be described with reference to FIG.

  The flowchart of FIG. 2 shows a routine for ignition retard control executed by the ignition retard control unit 36. The ignition retard control unit 36 executes this routine for each control cycle of the ECU. In the first step S2 of this routine, the ignition retard control unit 36 determines the presence or absence of a driver request, that is, a torque request from the driver, from the value of the driver request torque Tqd. When the driver depresses the accelerator pedal, the value of the driver request torque Tqd is determined according to the opening degree of the accelerator pedal. Therefore, if the value of the driver request torque Tqd is zero, it can be determined that there is no driver request.

  If it is determined that there is a driver request, the process by the ignition retard control unit 36 proceeds to step S4. In step S4, the ignition retard control unit 36 sets the ignition retard flag to “prohibited”. In other words, according to the ignition retard control by the ignition retard control unit 36, the retard of the ignition timing is prohibited in a situation where the driver requests torque by operating the accelerator pedal.

  On the other hand, if it is determined that there is no driver request, the process by the ignition retard control unit 36 proceeds to step S6. In step S6, the ignition retard control unit 36 determines whether or not there is an ECT request, that is, a torque request from the electronically controlled automatic transmission, from the value of the ECT required torque Tqect. The torque required by the electronically controlled automatic transmission includes a torque at the time of upshifting and a torque at the time of downshifting. This is a pulsed torque request. If the value of the ECT request torque Tqect is zero, it can be determined that there is no ECT request.

  If it is determined that there is an ECT request, the process by the ignition retard control unit 36 proceeds to step S8. In step S8, the ignition retard control unit 36 determines a period during which the retard of the ignition timing is prohibited. The reason why the ignition timing retarding prohibition period is provided when there is an ECT request is as follows.

  There is a delay time (mainly a delay time of the air response) until the change in the required torque Tq0 after the adjustment actually appears in the air amount. For this reason, when the post-arbitration required torque Tq0 changes in a pulse shape in the torque-up direction due to the ECT required torque Tqect, the air amount cannot follow the instantaneous change. When the air amount starts to increase due to the operation of the throttle, the requested torque Tq0 after the adjustment decreases to the original level. As a result, the estimated torque Tqe calculated from the current air amount becomes larger than the post-arrangement required torque Tq0, and the ignition timing calculation unit 34 determines the ignition delay amount according to the value of the ignition timing control efficiency η1. Calculated. However, if the ignition timing is retarded as calculated, the engine output torque is adjusted to the required torque Tq0 after arbitration, so the pulse-like torque change requested to the engine by the electronically controlled automatic transmission is It will not be realized. Therefore, in the ignition retard control by the ignition retard control unit 36, if there is an ECT request, the retard of the ignition timing is prohibited until the actual torque of the engine changes in a pulse shape in response to the request. Yes.

  The ignition timing retarding prohibition period is from the time when the pulse of the ECT required torque Tqect rises until a predetermined time elapses after the pulse falls to the original level. The predetermined time is determined based on a delay time until a change in the required torque appears in the air amount. Specifically, it is preferable to obtain a delay time by an experiment in advance for each operating condition, and add a margin in consideration of variation. Alternatively, a delay time may be estimated using an air model, and a time obtained by adding a margin considering variation to the estimated time may be set as the predetermined time.

  After the process of step S8, the process by the ignition retard control unit 36 proceeds to step S4. In step S4, the ignition retard control unit 36 sets the ignition retard flag to “prohibited” until the retard prohibition period determined in step S8 elapses. That is, according to the ignition delay control by the ignition delay control unit 36, when the torque-up request at the time of downshift is issued from the electronically controlled automatic transmission in a situation where there is no torque request from the driver, the above-described retardation is performed. Until the prohibition period elapses, retarding the ignition timing is prohibited. As a result, the actual torque of the engine is allowed to be larger than the post-arbitration required torque Tq0, and a pulse-like torque change required for the engine by the electronically controlled automatic transmission is realized. After the retard angle prohibition period has elapsed, the retard of the ignition timing is released, and the ignition retard control unit 36 sets the ignition retard flag to “permitted”.

  On the other hand, if it is determined that there is no ECT request, the processing by the ignition retard control unit 36 proceeds to step S10. In step S10, the ignition retard control unit 36 sets the ignition retard flag to “permitted”. That is, according to the ignition delay control by the ignition delay control unit 36, the ignition timing is retarded in a situation where there is no torque request from the driver and no torque request from the electronically controlled automatic transmission.

  Next, control effects obtained by the ignition delay control unit 36 performing the above-described ignition delay control will be described using a specific example shown in FIG.

  FIG. 3 shows the control results from (A) to (G) when the accelerator pedal is operated by the driver while the engine is idling and the electronically controlled automatic transmission is changed accordingly. Shown in two charts. Chart (A) shows the time change of the accelerator opening by the driver's operation, and Chart (B) shows the time change of the gear selection by the electronically controlled automatic transmission. Here, the accelerator pedal is depressed by the driver from time t1 to time t2, and the upshift is performed twice within that period. Then, downshifting by the electronically controlled automatic transmission is performed at a time point t4 after a while after the driver returns the accelerator pedal.

  Chart (C) represents the time change of various required torques input to the required torque arbitration unit 22. In this example, since the engine is idling, the ISC required torque is always input. Then, while the accelerator pedal is operated by the driver, a driver request torque having a magnitude corresponding to the accelerator opening is input. Further, when a shift change is performed by the electronically controlled automatic transmission, the ECT request torque is input prior to the shift change. In particular, when focusing on downshifting, a pulse-like ECT required torque in the torque-up direction is input from time t3 prior to downshifting to time t4 of downshifting.

  Chart (D) represents the temporal change in post-arbitration requested torque and estimated torque input to the ignition timing control efficiency calculator 32. In arbitration, the ECT required torque at the time of downshifting is added to the ISC required torque as it is, so the pulse-like waveform of the ECT required torque also appears in the required torque after arbitration. The target air amount is determined based on the post-arbitration required torque having such a waveform, and the throttle is operated to achieve it. However, since there is a delay in the response of the air amount to the operation of the throttle, the estimated torque calculated from the current air amount is delayed by at least the air response delay time with respect to the requested torque after arbitration.

  Chart (E) represents a change over time in the determination result of the ignition retard flag by the ignition retard control unit 36. As a result of performing the ignition delay control according to the flowchart of FIG. 2, the ignition delay flag is set to “prohibited” during the period from time t1 to time t2 when the driver request torque is input. Further, the ignition retard flag is set to “prohibited” from time t3 when the ECT request torque at the time of downshifting is input to time t5 when the retard prohibition period elapses.

  Chart (F) shows the change over time of the final ignition timing determined by the ignition timing calculation unit 34, and chart (G) shows the change over time of the torque output from the engine. In this example, since the engine is idling, a required efficiency η 0 having a value smaller than 1 for ensuring reserve torque is input to the control device 20. For this reason, during the period in which the ignition delay flag is “permitted”, the retard is performed with respect to the base ignition timing by the amount of the retard according to the value of the required efficiency η0. Also, during the period when the ignition delay flag is “permitted”, if the estimated torque becomes larger than the requested torque after arbitration, the ignition timing is further retarded according to the ratio of the requested torque after arbitration to the estimated torque. The

  Even when the ECT required torque at the time of downshifting is input, the estimated torque becomes larger than the post-arbitration required torque for a short period thereafter. However, the period after the input of the ECT request torque is included in the period from the time point t3 to the time point t5 (retarding prohibition period) when the ignition delay flag is set to “prohibited”. For this reason, although the estimated torque is larger than the requested torque after arbitration, the ignition timing is not retarded and the final ignition timing is maintained at the base ignition timing. As a result, the estimated torque becomes the engine output torque as it is, and a pulse-like change in the ECT required torque is also realized in the engine output torque.

  As can be seen from the above control example, according to the control device 20 according to the present embodiment, the final ignition timing is set to the base ignition timing for a predetermined period after the required torque after arbitration changes in a pulse shape in the torque-up direction. Maintained. As a result, the engine output torque is allowed to be excessive with respect to the required torque after arbitration during that period, so a pulse-like torque change in the torque-up direction required by the electronically controlled automatic transmission during downshifting Can be realized.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, when the prohibition of the retard of the ignition timing is canceled, as shown in FIG. 4, the ignition timing is gradually changed from the base ignition timing toward the ignition timing necessary to achieve the required torque. May be. Such a gradual change process is effective in preventing the occurrence of a torque step due to a sudden change in the ignition timing.

  Further, in the above-described embodiment, the retard of the ignition timing is prohibited when there is an ECT request. However, in order to achieve the purpose of realizing the pulse-like torque change, the ignition delay related to the final ignition timing is achieved. It is only necessary that the angular amount is limited with respect to the retardation amount necessary to achieve the required torque. In other words, the ignition retard amount may be limited so as not to exceed a predetermined guard value without setting it to zero. Alternatively, the ignition timing calculated by the ignition timing calculation unit 34 may be smoothed, and the ignition timing after the smoothing process may be determined as the final ignition timing.

DESCRIPTION OF SYMBOLS 10 Powertrain manager 12, 14, 16, 18 Request output element 20 Control apparatus 22 Request torque arbitration part 24 Air quantity control torque calculation part 26 Target air quantity calculation part 28 Throttle opening degree calculation part 30 Estimated torque calculation part 32 Ignition timing Control efficiency calculator 34 Ignition timing calculator 36 Ignition retard controller

Claims (6)

In a torque demand control type control device for cooperatively operating an actuator for changing the amount of air and an ignition device based on a required torque for an internal combustion engine,
Means for determining an operation amount of the actuator based on the required torque;
Means for calculating an ignition timing required to achieve the required torque based on a current air amount and the required torque;
When the required torque includes a pulse component in the torque-up direction, at least a predetermined period after the pulse component, the ignition delay amount related to the final ignition timing is the retardation amount necessary to achieve the required torque. Means to restrict against,
A control device for an internal combustion engine, comprising:   2. The control apparatus for an internal combustion engine according to claim 1, wherein the pulse component is a component generated when the automatic transmission is downshifted.   3. The control apparatus for an internal combustion engine according to claim 1, wherein the means for limiting the ignition retard amount is a means for prohibiting the retard of the ignition timing.   The means for limiting the ignition delay amount gradually changes the ignition timing toward the ignition timing necessary to achieve the required torque when canceling the prohibition of the ignition timing retardation. The control apparatus for an internal combustion engine according to claim 3.   3. The control apparatus for an internal combustion engine according to claim 1, wherein the means for limiting the ignition retard amount is a means for setting a predetermined guard value with respect to the retard amount of the ignition timing.   3. The control apparatus for an internal combustion engine according to claim 1, wherein the means for limiting the ignition retard amount is means for smoothing a calculated value of the ignition timing.

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