JP4821595B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a technical field of a control device for an internal combustion engine capable of executing so-called torque demand control for controlling the internal combustion engine according to a target torque.

  As this type of device, one that corrects the ignition timing during transient operation has been proposed (see, for example, Patent Document 1). According to the torque control device for an internal combustion engine disclosed in Patent Document 1 (hereinafter referred to as “conventional technology”), it is based on a target torque set according to an engine load, an engine rotational speed, an air charge amount, and the like. By correcting the ignition timing according to the deviation from the corrected estimated torque obtained by correcting the estimated torque calculated so that the estimated torque approaches the target torque side, the excess or deficiency of the actual torque with respect to the target torque can be calculated. It is said that it can be corrected with high accuracy.

  From the viewpoint of preventing noise, there has been proposed a device that prohibits the retard when the ignition retard is executed at the time of acceleration and the load increase speed exceeds a predetermined value (for example, see Patent Document 2).

  From the viewpoint of preventing vibration, an apparatus that performs ignition retard control based on the engine rotation fluctuation amount during acceleration has been proposed (see, for example, Patent Document 3).

JP 2002-221068 A JP-A-63-208672 JP 2003-65196 A

  In the conventional technology, by improving the followability to the target torque, the comfort including the drivability is improved. On the other hand, it is difficult to avoid the deterioration of the fuel consumption as a contradiction to retarding the ignition timing. In particular, in situations where power performance is remarkably required, such as during rapid acceleration, a decrease in power performance due to retarding the ignition timing does not necessarily lead to an improvement in drivability. On the contrary, a decrease in acceleration performance can be dissatisfied with the driver and may lead to a decrease in comfort. Therefore, when the corrected estimated torque is larger than the target torque, the ignition timing is retarded, and in some cases, the overall performance of the vehicle including the economy such as comfort and fuel consumption may be significantly lowered. That is, the conventional technique has a technical problem that the overall performance of the vehicle may be lowered when the internal combustion engine is controlled according to the target torque.

  The present invention has been made in view of the above-described problems, and provides a control device for an internal combustion engine that can suppress a decrease in the overall performance of the vehicle when the internal combustion engine is controlled in accordance with a target torque. This is the issue.

In order to solve the above-described problems, an internal combustion engine control apparatus according to the present invention is an internal combustion engine control apparatus that controls the internal combustion engine in a vehicle including the internal combustion engine, and is a target to be output from the internal combustion engine. Target torque specifying means for specifying torque, throttle control means for controlling the throttle opening in the internal combustion engine so that the target torque is output, and actual torque specifying means for specifying the actual torque output from the internal combustion engine And, when the actual torque is greater than the target torque, a retard control that executes a retard control that is defined as retarding the ignition timing in the internal combustion engine so that the actual torque approaches the target torque to define a unit, and the retard limit means for limiting the execution of the retard control in accordance with a predetermined type of operating condition in the internal combustion engine, the operating conditions Torque change specifying means for specifying the degree of change in the target torque as an index value, and the retard restriction means restricts execution of the retard control according to the degree of change, and the torque change The specifying unit specifies the degree of change as a target torque gradient value corresponding to the amount of change in the target torque per unit time, and the retardation limiting unit sets the target torque gradient value in a negative range. Execution of the retardation control is limited when the threshold value is equal to or greater than the first threshold value, and in order to avoid deterioration of drivability, the execution of the retardation control is limited to an area below the first threshold value. It is a prohibited area .

  The “internal combustion engine” in the present invention has, for example, a plurality of cylinders, and in each of the combustion chambers, an explosion force generated when an air-fuel mixture containing various fuels such as gasoline or alcohol burns, for example, pistons This is a concept that encompasses an engine that can be extracted as power through a connecting rod, a crankshaft, and the like as appropriate, and refers to, for example, a 2-cycle or 4-cycle reciprocating engine.

  According to the control device for an internal combustion engine of the present invention, during operation, the target torque is configured as various processing units such as an ECU (Electronic Control Unit), various controllers or various computer systems such as a microcomputer device, or the like. By the action of the specifying means, for example, a target torque representing a torque to be output from the internal combustion engine is specified as a torque requested by the driver.

  Here, “specific” in the present invention refers to, for example, detecting directly or indirectly as a physical numerical value or an electrical signal corresponding to the physical numerical value via some detection means, appropriate storage means, etc. Select or estimate the corresponding numerical value from the map etc. stored in, and derive from the detected physical numerical value or electrical signal or the selected or estimated numerical value according to a preset algorithm or calculation formula, etc. Alternatively, it is a broad concept encompassing simply obtaining values, etc. detected, selected, estimated or derived in this way as electrical signals or the like.

  Within the scope of such a concept, the target torque specifying means requests the driver based on, for example, an operation amount related to the operation of the accelerator pedal performed by the driver (hereinafter referred to as “accelerator opening” as appropriate). The acceleration is calculated, and further, for example, the target torque is specified as a result of performing a numerical operation or a logical operation based on the acceleration.

  When the target torque is specified, the throttle control means configured as various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device, for example, from a map or the like stored in an appropriate storage means. The throttle opening (that is, opening / closing of the throttle valve) is performed so that the target torque is output by selecting a corresponding numerical value, or by performing logical operation or numerical operation according to an appropriate algorithm or calculation formula each time. Control).

  On the other hand, apart from such target torque, actual torque representing torque output from the internal combustion engine is, for example, actual torque specifying means configured as various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. Specified by. At this time, for example, an intake air amount (that is, load) estimated by various detection means such as an AFM (Air Flow Meter), or an actual load ratio (that is, a ratio of the load to the maximum load) calculated from the intake air amount, and Based on a reference ignition timing (hereinafter referred to as “base ignition timing” where appropriate) set as a fixed or variable value, a corresponding numerical value is obtained from a map or the like that is stored in appropriate storage means. The actual torque is specified by being selected, or by performing logical operation or numerical operation according to an appropriate algorithm or calculation formula each time.

  Here, it is ideal that the target torque and the actual torque match each other, but since the response of the intake air amount is poor with respect to the change in the throttle opening, the actual torque is calculated only by the throttle opening. It can be difficult to accurately follow this.

  Therefore, in the control apparatus for an internal combustion engine according to the present invention, the actual torque should be brought close to the target torque by the retard control means configured as various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. Delay angle control is performed to retard the ignition timing. Since the actual torque is at least reduced by retarding the ignition timing, this retard control is of course executed when the actual torque is larger than the target torque.

  For example, when the ignition timing is set only in the retard region (that is, the retard side relative to TDC) or set significantly in the retard region, the actual torque should not be insufficient with respect to the target torque. A controlled method may be employed in which excessive torque is reduced by retarding the ignition timing. In this case, the actual torque is inevitably excessive with respect to the target torque, and the execution opportunity of the retard control can be increased. Since the response speed of the ignition timing is obviously faster than the response speed of the intake air amount, in general, in this case, the actual torque is controlled roughly by the throttle opening and finely by the ignition timing. Will be.

  Thus, the target torque specifying means, the throttle control means, the actual torque specifying means and the retard angle control means execute control of the throttle opening and ignition timing based on the target torque, in other words, so-called torque demand control. By making the actual torque follow the target torque, comfort including drivability is ensured.

  On the other hand, for example, in situations where power performance is remarkably required, such as during sudden acceleration or sudden start, power performance is more likely to be prioritized than following the actual torque to the target torque, so retard the ignition timing. If the actual torque is reduced by this, the power performance is lowered, and as a result, the comfort may be lowered. Further, since the fuel consumption is correspondingly deteriorated by retarding the ignition timing, in such a case, the overall performance of the vehicle including the comfort such as the fuel consumption tends to be lowered. Therefore, in the control apparatus for an internal combustion engine according to the present invention, a decrease in the overall performance of the vehicle in torque demand control is suppressed as follows.

  In other words, according to the control apparatus for an internal combustion engine according to the present invention, during operation, the internal combustion engine includes, for example, retard limit means configured as various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. Execution of the retard control is restricted according to a predetermined type of operating condition.

  Here, in the present invention, “restricting the execution” means that the retard amount of the ignition timing is directly or indirectly, in a binary, stepwise or continuous manner in addition to prohibiting the execution. In other words, the ignition timing is compared with the case where the ignition timing is not limited in any way, including reducing the degree of retardation of the ignition timing in a binary, stepwise or continuous manner. It is a concept encompassing approaching the base ignition timing to some extent. “Prohibit execution of retard angle control” means that the retard amount of the ignition timing is reduced and corrected so that the ignition timing becomes zero or a small value that can be substantially regarded as zero. It may be realized.

  Here, the “predetermined type of driving condition” according to the present invention is a condition that correlates with the overall performance of the vehicle including comfort, including drivability, economy such as fuel efficiency, and dynamics such as acceleration performance. The concept can include, for example, the degree of acceleration of the vehicle, the degree of loss of the internal combustion engine associated with execution of the retard control, or the degree of change in the target torque. At this time, a criterion for how to reflect this type of operating condition in the restriction of execution of the retard control is, for example, in advance experimentally, empirically, theoretically or based on simulation, For example, the overall performance of the vehicle can be optimized as much as possible in consideration of the priorities and balances of the comfort, economy and power mentioned above, or the degree of influence of the retard control on each of them. May be determined.

According to such retard angle limiting means, for example, retarding the ignition timing at the time of acceleration or the like is prohibited, and both comfort and economy are achieved, or loss due to retarding the ignition timing is reduced. By converging to a range that is practically acceptable, various benefits such as ensuring the comfort by causing the actual torque to follow the target torque while suppressing a remarkable deterioration in economy can be provided. That is, according to the control device for an internal combustion engine according to the present invention, it is possible to suppress a decrease in the overall performance of the vehicle when the torque demand control is executed.
In particular, the control device for an internal combustion engine according to the present invention further includes torque change specifying means for specifying the degree of change in the target torque as an index value for defining the operating condition, The execution of the retard control is limited according to the degree of this change.
That is, in the control device for an internal combustion engine according to the present invention, the degree of change in the target torque is suitably set by the torque change specifying means configured as various processes such as an ECU, various controllers or various computer systems such as a microcomputer device. Is specified as some index value representing the degree, for example, as a time change amount of the target torque. The specified degree of change is provided as at least a part of the predetermined type of operating condition, that is, as a determination index related to the restriction of execution of the retard control.
The degree of change in the target torque can be an index for determining what is prioritized among the elements that define the overall performance of the vehicle. Therefore, it is possible to ensure the overall performance of the vehicle by restricting the execution of the retard control according to the degree of the change.
More specifically, the torque change specifying unit is configured to specify the degree of change as a target torque gradient value corresponding to the amount of change in the target torque per unit time.
This target torque gradient value is a value of the slope of a straight line representing the time change of the target torque, and is suitable as an index value that defines the degree of change in the target torque.
In consideration of these points, the control device for an internal combustion engine according to the present invention provides the retard angle control means when the target torque gradient value is equal to or greater than the first threshold value set in the negative range. It is the structure which restricts execution of.
When the target torque gradient value is in a negative range, in view of the concept of the target torque gradient value, for example, the driver's braking operation, road surface condition, internal combustion engine friction, shift request from AT (Automatic Transmission), or FC ( The target torque decreases with the execution of Fuel Cut. At this time, in particular, when a relatively large reduction in the target torque occurs, there is a high possibility that it is due to an AT shift request or some other request generated in the vehicle.
In such a case, if the actual torque does not follow the target torque, drivability may be significantly deteriorated and the overall performance of the vehicle may be reduced. Accordingly, the first threshold value is set in a negative range, and execution of the retard control is restricted when the target torque gradient value is equal to or greater than the first threshold value, thereby avoiding deterioration in drivability, and the vehicle It is possible to guarantee the overall performance of the system. The first threshold value is preferably set to a correspondingly small value (large in absolute value) so that it can be defined that a relatively large reduction in target torque has occurred as described above. .
In the present invention, “greater than” is a concept that can be interchanged with “more than” depending on how the reference value is set. Similarly, “less than” is “less than” depending on how the reference value is set. It is a concept that can be mutually replaced.

  In one aspect of the control apparatus for an internal combustion engine according to the present invention, the control apparatus further includes a transient determination unit that determines whether or not the internal combustion engine is in a transient state, and the retard restriction unit includes The execution of the retard control is limited when the determination that the state is in a transient state is made.

  According to this aspect, for example, the internal combustion engine is brought into a transient state such as a sudden acceleration state or a sudden start state by the transient determination means configured as various processes such as an ECU, various controllers or various computer systems such as a microcomputer device. A determination is made whether or not there is. The retard angle limiting means limits execution of the retard angle control when it is determined by the determining means that the internal combustion engine is in a transient state.

  Here, the “transient state” according to the present invention refers to a state in which the longitudinal acceleration of the vehicle (hereinafter referred to as “front-rear G” as appropriate) is relatively large, and the variation in the engine speed of the internal combustion engine is relatively large. Alternatively, it is a concept that includes a state in which various index values that define the operating state of the internal combustion engine are relatively large, including a state in which the fluctuation of the target torque or the actual torque is relatively large. In this type of transient state, even if the ignition timing is retarded, it is easy to have practical difficulties in following the actual torque to the target torque, and the deterioration of fuel consumption due to execution of the retard angle control becomes relatively obvious. easy.

  Therefore, when the execution of the retard control is restricted during such a transition period, it becomes possible to relatively improve the fuel efficiency without revealing a decrease in comfort, and to improve the overall performance of the vehicle. It is possible to suppress the decrease. At this time, there is no particular limitation as to what kind of aspect the retard angle control is restricted to, the execution of the retard angle control itself may be prohibited as described above, and the retard amount may be constant or indefinite. The amount may be reduced by the amount. Also, “when it is determined that it is in the transition period” does not have to be all of the case where it is determined that it is in the transition period, but when it is determined that it is in the transition period. It may be at least a part.

  It should be noted that the mode of determination of the transient state according to the determination means is to determine that the operating state of the internal combustion engine is such that the deterioration of the overall performance of the vehicle can be suppressed by prohibiting execution of the retard control. It is not limited at all as much as possible, and the determination criteria may be determined in advance as, for example, experimentally, empirically, theoretically or based on simulation or the like that can ensure sufficient accuracy in practice. Good.

  In this aspect, the transient state includes a WOT acceleration state in which the throttle opening is maximum and the vehicle is accelerating.

  In this case, the transient state includes a WOT (Wide Open Throttle) acceleration state. In the WOT acceleration state, since the vehicle is accelerating with the throttle opening being maximum, power performance is remarkably required. In this case, the driver often requests the maximum acceleration. When the ignition timing is retarded in a state where the power performance is remarkably required in this way, as described above, the power performance is lowered and the comfort is lowered, and the fuel consumption is not avoided. The overall performance of the vehicle may be significantly reduced. Therefore, when the execution of the retard angle control is limited in the WOT acceleration state, a decrease in the overall performance of the vehicle is extremely effectively suppressed.

  In the aspect provided with the transient state determining means, the retardation limiting means may restrict the execution of the retardation control by prohibiting the execution of the retardation control.

  In the transient state, the effect of the retard control is difficult to appear, and the deterioration of fuel consumption tends to increase. Therefore, in such a case, it is possible to more effectively suppress a decrease in the overall performance of the vehicle by prohibiting execution of the retard control. Note that “prohibiting execution of the retard control” means that the mode is not limited as long as an effect equivalent to the fact that the retard control is not actually executed is obtained. The retard amount of the ignition timing that can be determined by the means may be corrected to be reduced to a value that is small enough to be regarded as zero or substantially zero, and the retard control is executed regardless of the retard amount. Control may be prohibited.

  In another aspect of the control apparatus for an internal combustion engine according to the present invention, loss control means for specifying a loss of the internal combustion engine due to execution of the retardation control is further provided as an index value that defines the operating condition. The retard limiter limits the execution of the retard control by correcting the retard amount of the ignition timing to be reduced according to the loss.

  According to this aspect, for example, the loss in the internal combustion engine caused by the retard angle control is caused by, for example, the value of the loss energy by the loss identification means configured as various processes such as ECU, various controllers or various computer systems such as a microcomputer device. Identified as At this time, for example, an index value that defines the loss (for example, a value of loss energy) and a retard amount related to the retard control or a torque corresponding to the retard amount (that is, a deviation between the target torque and the actual torque). ) Etc., the corresponding numerical value is selected from a map or the like, or the loss is practically sufficiently accurate based on experiments, empirical, theoretical or simulation. However, the loss is specified by performing a logical operation or a numerical operation based on an algorithm or a calculation formula set so as to be derived. The identified loss is provided as at least a part of the predetermined type of operating condition, that is, as a determination index related to the restriction of execution of the retard control. In addition, in view of the specific concept described above, “specifying a loss” is intended to include acquiring not only the loss itself but also an index value corresponding to the loss on a one-to-one or many-to-one basis. .

  When limiting the execution of the retard control in accordance with the specified loss, the retard control means determines the retard amount of the ignition timing related to the retard control, for example, so that the loss becomes a predetermined value or less, or Execution of the retard control is limited by correcting the decrease so that the predetermined rate decreases or the loss decreases by a predetermined amount. Therefore, according to this aspect, the retard amount is reduced in a binary, stepwise or continuous manner according to the loss of the internal combustion engine having a correlation with the fuel consumption, and the overall performance of the vehicle is efficiently and effectively Secured by

  In this aspect, the retard angle limiting means may limit the execution of the retard angle control when the loss is larger than a predetermined upper limit value.

  Since the loss in the internal combustion engine is a factor directly related to the fuel consumption, the deterioration of the fuel consumption, which cannot be ignored in practice, for example, based on the experiment in advance, empirically, theoretically or based on simulation, etc. The upper limit value can be set as a value that can be generated or a value obtained by adding a constant or indefinite margin to such a value from the viewpoint of preventing deterioration of fuel consumption. At this time, if the execution of the retard control is limited when the loss is larger than the upper limit value (in this case, the retard amount is corrected), for example, the actual torque follows the target torque to ensure comfort. On the other hand, it is possible to reliably prevent the deterioration of fuel consumption that cannot be ignored in practice, which is extremely beneficial.

  As described above, in the aspect in which the upper limit value is set for the loss, the retard angle limiting unit may limit the execution of the retard angle control so that the loss is equal to or less than the upper limit value.

  As a result of restricting the execution of the retard angle control, if the loss still exceeds the upper limit value, the deterioration of the fuel consumption may become apparent depending on how the upper limit value is set. In this way, when the retard amount is corrected so that the loss becomes equal to or less than the upper limit when restricting the execution of the retard control, the actual torque is set to the target torque while reliably preventing the deterioration of fuel consumption. It is possible to ensure a certain level of comfort improvement effect by following, which is useful in practice. As a preferred embodiment of “below the upper limit value”, an upper limit value or a value close to the upper limit value that can be regarded as the upper limit value may be adopted.

In another aspect of the control apparatus for an internal combustion engine according to the present invention, the retard angle limiting means includes a second threshold value in which the target torque gradient value is set in the negative range and is larger than the first threshold value. The retard control is performed by prohibiting the execution of the retard control when the fuel efficiency is prioritized over the drivability, which is equal to or less than the third threshold set in the positive range. to limit the execution.

  In this case, the range from the second threshold value to the third threshold value is a range in which the absolute value of the target torque gradient value is relatively small, in other words, the degree of change in the target torque is small. In such a range, the deterioration of drivability is difficult to be realized without causing the actual torque to follow the target torque. Therefore, in such a case, the deterioration of the overall performance of the vehicle is suppressed by avoiding the deterioration of the fuel consumption caused by retarding the ignition timing. The second threshold value is not particularly limited as long as it is larger than the first threshold value (in terms of the negative range, it is small as an absolute value), but in view of the nature of profits that can be enjoyed. For example, the value is set to a correspondingly large value (small in absolute value) so that it can be defined that a relatively small reduction in the target torque has occurred.

  In the case where the second range is set, the retard angle limiting means further includes the target torque gradient value in a first range that is not less than the first threshold and less than the second threshold, and The execution of the retard control may be limited by correcting the retard amount of the ignition timing by decreasing when the second range is larger than the third threshold.

  Qualitatively speaking, the first range and the second range are regions where the target torque changes accordingly. In such a region, it is necessary to pursue comfort while suppressing deterioration in fuel consumption. When the retard amount of the ignition timing is corrected to decrease, the retard control of the ignition timing is limited as a typical meaning (that is, is not prohibited). A balance with improvement is achieved, and a decrease in the overall performance of the vehicle is effectively suppressed.

  In addition, as one aspect suitable for achieving both comfort and economy in this way, based on the loss resulting from the execution of the retard control described above, for example, the loss becomes a predetermined upper limit value or less. Alternatively, the retard amount may be corrected to decrease so that the loss converges to a predetermined range.

  Further, in this case, the retardation limiting means restricts execution of the retardation control when the target torque gradient value is in the first range and the vehicle is not in a deceleration state. Also good.

  Even if the target torque gradient value is in the first range, if the vehicle is in a decelerating state, the execution of the retard angle control is limited, which may cause a deterioration in drivability. As described above, when the execution of the retard control is restricted when the vehicle is not in the deceleration state, preferably the execution of the retard control can be permitted when the vehicle is in the deceleration state. Is precisely controlled, and the deterioration of the overall performance of the vehicle is further effectively suppressed.

  The determination as to whether or not the vehicle is in the deceleration state may be made based on, for example, the operation state (operation amount or operation speed) of the brake pedal. In particular, it may be determined so as to effectively suppress a decrease in the overall performance of the vehicle based on experience, theory, or simulation.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

<Embodiment of the Invention>
Various preferred embodiments of the present invention will be described below with reference to the drawings.
<First Embodiment>
<Configuration of Embodiment>
First, the configuration of the engine system 10 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram of the engine system 10.

  1, the engine system 10 is mounted on a vehicle (not shown) and includes an ECU 100, an engine 200, a brake pedal 300, a brake pedal sensor 310, an accelerator pedal 400, and an accelerator position sensor 410.

  The ECU 100 is an electronic control unit that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and controls the entire operation of the engine 200. It is an example of “apparatus”.

  The engine 200 is a gasoline engine that functions as a power source for a vehicle, and is an example of an “internal combustion engine” according to the present invention. The engine 200 causes the air-fuel mixture to explode by the ignition operation of the ignition device 202 in which a part of the spark plug that is part of the cylinder 201 is exposed, and the reciprocating motion of the piston 203 that occurs according to the explosive force is connected. It can be converted into a rotational motion of the crankshaft 205 via the rod 204. A crank position sensor 206 that detects the rotational position of the crankshaft 205 is installed in the vicinity of the crankshaft 205. The crank position sensor 206 is electrically connected to the ECU 100, and the ECU 100 can control the ignition timing of the ignition device 202 based on the rotational position of the crankshaft 205 detected by the crank position sensor 206. It is configured. Further, the ECU 100 is configured to be able to calculate the engine speed Ne of the engine 200 based on the rotational position of the crankshaft 205. Below, the principal part structure of the engine 200 is demonstrated with a part of the operation | movement.

  When the fuel in the cylinder 201 is burned, the air sucked from the outside passes through the intake pipe 207 and is mixed with the fuel injected from the injector 214 at the intake port 213 to become the above-mentioned air-fuel mixture. The fuel is stored in the fuel tank 215 and is pumped and supplied to the injector 214 via the delivery pipe 216 by the action of the low pressure pump 217. The injector 214 is electrically connected to the ECU 100, and is configured to be able to inject the supplied fuel into the intake port 213 according to the control of the ECU 100.

  The communication state between the inside of the cylinder 201 and the intake pipe 207 is controlled by opening and closing the intake valve 218. The air-fuel mixture combusted in the cylinder 201 becomes exhaust gas and is guided to the exhaust pipe 221 via the exhaust port 220 when the exhaust valve 219 that opens and closes in conjunction with opening and closing of the intake valve 218 is opened.

  A cleaner 208 is disposed on the intake pipe 207 to purify air sucked from the outside. An air flow meter 209 is disposed on the downstream side (cylinder side) of the cleaner 208. The air flow meter 209 has a form called a hot wire type, and is configured to be able to directly detect the mass flow rate of the sucked air (that is, the intake air amount). The air flow meter 209 is electrically connected to the ECU 100, and the detected mass flow rate of the intake air is grasped by the ECU 100 continuously or at a constant or indefinite period.

  A throttle valve 210 capable of adjusting the amount of intake air related to the intake air sucked into the cylinder 201 is disposed downstream of the air flow meter 209 in the intake pipe 207. A throttle position sensor 212 is electrically connected to the throttle valve 210, and is configured to be able to detect the throttle opening that is the opening. Note that the throttle position sensor 212 is electrically connected to the ECU 100, and the detected throttle opening degree is constantly recognized by the ECU 100 at a constant or indefinite period.

  On the other hand, ECU 100 controls the drive state of throttle valve motor 211 based on an accelerator opening detected by an accelerator position sensor 410 described later. The throttle valve 210 is configured to be driven by the driving force of the throttle valve motor 211. The throttle valve 210 is an electronically controlled throttle valve that is driven by the driving force of the throttle valve motor 211 controlled by the ECU 100. The throttle opening is determined by the ECU 100 according to the driver's intention (that is, the accelerator opening). ) Can be controlled independently.

  A three-way catalyst 223 is installed in the exhaust pipe 221. The three-way catalyst 223 is a catalyst capable of purifying CO (carbon monoxide), HC (hydrocarbon), and NOx (nitrogen oxide) discharged from the engine 200, respectively. An air-fuel ratio sensor 222 is disposed upstream of the three-way catalyst 223 in the exhaust pipe 221. The air-fuel ratio sensor 222 is configured to detect the air-fuel ratio of the engine 200 from the exhaust gas discharged through the exhaust port 220. The air-fuel ratio sensor 222 is electrically connected to the ECU 100, and the detected air-fuel ratio is constantly grasped by the ECU 100.

  A temperature sensor 224 for detecting the temperature of the cooling water for cooling the engine 200 is disposed in the water jacket installed in the cylinder block that houses the cylinder 201. The temperature sensor 224 is electrically connected to the ECU 100, and the detected engine coolant temperature is grasped by the ECU 100 continuously or at a constant or indefinite period.

  The brake pedal 300 is a pedal operated by a driver, and the vehicle is configured to be braked when the brake pedal is operated. The brake operation amount that is the operation amount of the brake pedal 300 is detected by a brake pedal sensor 310 disposed in the vicinity of the brake pedal 300. The brake pedal sensor 310 is electrically connected to the ECU 100, and the detected brake operation amount is grasped by the ECU 100 continuously or at a constant or indefinite period.

  The ECU 100 is electrically connected to a control system of a braking device (not shown) that applies a braking force to each wheel of the vehicle, for example, a brake actuator, and the brake operation amount detected by the brake pedal sensor 310. The braking force is controlled according to the above.

  The accelerator pedal 400 is a pedal operated by the driver. The accelerator pedal 400 is a pedal that is remarkably operated when the driver seeks acceleration, and the accelerator opening that is the operation amount is used when the opening of the throttle valve 210 is controlled as described above. . An accelerator position sensor 410 is installed in the vicinity of the accelerator pedal 400 so that the accelerator opening is detected in real time. The accelerator position sensor 410 is electrically connected to the ECU 100, and the detected accelerator opening is grasped by the ECU 100 continuously or at a constant or indefinite period.

<Operation of Embodiment>
Below, operation | movement of the engine system 10 which concerns on this embodiment which has the said structure is demonstrated.

<Torque demand control>
In the engine system 10, the operation state of the engine 200 is controlled by the ECU 100 according to the target torque, and so-called torque demand control is executed. Here, the details of the torque demand control will be described with reference to FIG. FIG. 2 is a block diagram conceptually showing the logic of torque demand control.

  In FIG. 2, the ECU 100 stores three types of maps: a throttle opening map 101, a torque map 102, and a retard amount map 104.

  The throttle opening map 101 is a map in which the throttle opening instruction value thr of the engine 200 is set in association with the target torque Trref. The ECU 100 acquires the target torque Trref, refers to the throttle opening map 101, and determines a throttle opening instruction value thr by selecting a value corresponding to the acquired target torque Trref. The ECU 100 controls the throttle valve motor 211 as described above based on the determined throttle opening instruction value thr, and controls the open / closed state of the throttle valve 210 (that is, the throttle opening).

  At this time, the ECU 100 calculates the longitudinal acceleration requested by the driver from the accelerator opening obtained via the accelerator position sensor 410, and calculates the target torque Trref based on the longitudinal acceleration. Target torque Trref is a required torque requested by the driver, and represents a torque to be output from engine 200. The acquired value of the target torque Trref is used for determination of the throttle opening instruction value thr and is output to the adder / subtractor 103 described later.

  The torque map 102 is a map in which estimated torque (ie, an example of “actual torque” according to the present invention) Trmes representing an estimated value of actual torque output by the engine 200 is stored.

  The ECU 100 calculates the actual load factor KL based on the intake air amount detected by the air flow meter 209 and the engine maximum intake air amount, and acquires the base ignition timing pgbse stored in advance in the ROM. The torque map 102 stores the value of the estimated torque Trmes in a form associated with the actual load ratio KL and the base ignition timing pgbse, and the ECU 100 selects the corresponding numerical value to thereby calculate the estimated torque Trmes. Get the value. The acquired estimated torque Trmes value is output to the adder / subtractor 103. Further, the value of the base ignition timing pgbse is used for obtaining the estimated torque Trmes and is output to the adder / subtractor 105 described later.

  In the adder / subtractor 103, the value of the estimated torque Trmes is subtracted from the value of the target torque Trref. As a result, the torque deviation value corresponding to “Trref−Trmes” is output from the adder / subtractor 103 to the retardation amount map 104. In the retard amount map 104, a retard amount DL indicating how much the ignition timing of the ignition device 202 is retarded with respect to the base ignition timing is stored in association with the value of the torque deviation. Since the actual torque of the engine 200 decreases by retarding the ignition timing, the value of the deviation is negative in the retard amount map 104 (that is, when the estimated torque Trmes is greater than the target torque Trref). A significant retardation amount is set only for. In other cases, the retardation amount is set to zero.

  The ECU 100 selects the corresponding retardation amount DL from the retardation amount map 104 and outputs it to the adder / subtractor 105. As described above, the value of the base ignition timing pgbse is output to the adder / subtractor 105, and the adder / subtracter 105 performs a subtraction process corresponding to “pgbse-DL”, and finally the ignition timing instruction value pg. Is calculated. ECU 100 controls ignition device 202 based on this determined ignition timing instruction value pg, and controls the ignition timing of engine 200.

  Thus, in the engine system 10, the ignition timing retard amount DL is set and the ignition timing is retarded when the estimated torque Trmes is greater than the target torque Trref. In other words, the ignition timing retarding control, which is an example of the “retarding control” according to the present invention, is executed. As a result, the estimated torque Trmes can be made to follow the target torque Trref, and comfort including drivability can be improved.

  Here, the execution process of such torque demand control will be described visually with reference to FIG. FIG. 3 is a chart showing the transition of the operating state of the engine 200.

  In FIG. 3, the horizontal axis represents time, and the vertical axis represents torque, throttle opening THR, actual load factor KL, and ignition timing PG in order from the top. The throttle opening THR represents the actual opening of the throttle valve 210 that has been controlled based on the throttle opening instruction value thr, and the ignition timing PG represents the ignition timing based on the ignition timing instruction value pg described above. It represents the actual ignition timing of the ignition device 202 that has undergone control.

  In FIG. 3, it is assumed that the target torque Trref (solid line in the torque graph) changes from Tr1 to Tr0 at time T0. At this time, the throttle opening THR changes from the previous THR1 to THR0 through the change of the throttle opening instruction value thr according to the change of the target torque Trref.

  However, the rate of change of the intake air amount is slower than the rate of change of the throttle opening THR, and the actual load factor KL instantaneously changes from the previous KL1 to KL0 corresponding to the throttle opening THR0 at time T0. Instead, KL0 is reached at time T1 after a corresponding time delay. Therefore, the estimated torque Trmes (the broken line in the torque graph) representing the actual torque of the engine 200 does not change instantaneously from Tr1 at time T0, but follows the target torque Trref for the first time at time T1. That is, the estimated torque Trmes becomes larger than the target torque Trref from time T0 to time T0.

  For this reason, the ignition timing PG is retarded from time T0 to time T1 by the ignition timing retarding control described above. That is, the ignition timing PG is retarded from the base ignition timing PGBSE (that is, the ignition timing corresponding to the base ignition timing instruction value pgbse) to PGDL at time T0, and the retard amount is gradually decreased until time T1. At T1, the base ignition timing PGBSE is restored. With such control of the ignition timing PG, the follow-up delay of the estimated torque Trmes as indicated by the broken line in the torque graph is eliminated, and the actual torque of the engine 200 follows the target torque Trref, which includes drivability. Comfort is guaranteed.

  Here, with reference to FIG. 4, the case where such ignition timing retardation control is applied during WOT acceleration will be described. FIG. 4 is a chart showing the transition of the operating state of the engine 200 during WOT acceleration. In the figure, the same reference numerals are given to the same portions as those in FIG. 3, and the description thereof will be omitted as appropriate. “WOT acceleration” refers to a period during which the vehicle is accelerating with the throttle valve 210 fully open.

  In FIG. 4, FIG. 4A shows a case where the estimated torque Trmes follows the target torque Trref. That is, the target torque Trref starts increasing at time T2, and accordingly, the throttle opening THR is set to THRmax (that is, WOT) corresponding to full open. At this time, since the estimated torque Trmes follows the target torque Trref, the ignition timing PG remains constant at the base ignition timing PGBSE without being retarded. At this time, the base ignition timing PGBSE may be slightly retarded from the viewpoint of suppressing the occurrence of knocking due to WOT acceleration.

  On the other hand, FIG. 4B shows a case where the estimated torque Trmes does not follow the target torque Trref but becomes larger than the target torque Trref. In this case, even when the target torque Trref starts increasing at time T2, and the throttle opening THR is set to THRmax accordingly, the estimated torque Trmes is larger than the target torque Trref, so that the torque deviation described above is negative. Thus, the retardation amount DL is set, and the ignition timing PG is retarded from the base ignition timing PGBSE.

  Here, at the time of such WOT acceleration, the actual torque of the engine 200 is generally smaller than the target torque Trref due to the follow-up delay of the intake air amount, and FIG. As described above, the estimated torque Trmes is rarely larger than the target torque Trref. Therefore, in this case, there is a possibility that the estimated torque Trmes cannot accurately estimate the actual torque due to the detection accuracy and variation of the air flow meter 209 that detects the intake air amount. If the ignition timing is retarded in a state where the accuracy of the estimated torque Trmes is not ensured, there is a possibility that the retarding control of the ignition timing may be executed even though it is not necessary, and the deterioration of the acceleration performance is caused to the driver. It can be frustrating and reduce comfort. Alternatively, if the estimated torque Trmes can accurately estimate the actual torque, that is, if the actual torque actually exceeds the target torque Trref for some reason, the driver may step on the accelerator pedal 400, for example. In view of the situation where relatively rapid acceleration is demanded in the WOT state, the larger the actual torque, the more the driver's request is satisfied, and there is almost no benefit from retarding the ignition timing. On the contrary, a decrease in power performance due to torque suppression may cause the driver to be dissatisfied. That is, in any case, at the time of WOT acceleration, the deterioration of fuel consumption due to the ignition timing delay control is clearly more obvious than the contribution to comfort including drivability, and there is a need to retard the ignition timing. It is extremely easy to decrease.

  Therefore, in the present embodiment, the ECU 100 executes the ignition timing control process separately from the torque demand control logic described with reference to FIG. 2, so that the torque demand with a retarded ignition timing is taken into consideration while considering the overall performance of the vehicle. Control is possible. Here, the details of the ignition timing control process will be described with reference to FIG. FIG. 5 is a flowchart of the ignition timing control process.

  In FIG. 5, the ECU 100 obtains the throttle opening instruction value thr and the ignition timing instruction value pg determined by the torque demand control logic described in FIG. 2 (step A10).

  Next, the ECU 100 determines whether or not the retard amount DL of the ignition timing is set as a value larger than 0 in the torque demand control logic, that is, the retard amount DL that is not zero based on the retard amount map 104 is determined. It is determined whether or not it has been set (step A11). When the retard amount DL is zero, that is, when the ignition timing instruction value pg is determined without retarding the ignition timing (step A11: NO), the ECU 100 proceeds to step A14. Then, the ignition timing is controlled based on the ignition timing instruction value pg obtained in the processing according to step A10. After the ignition timing control according to step A14, the process is returned to step A10, and the processes after step A10 are repeated.

  On the other hand, if the retard amount DL is not zero (step A11: YES), the ECU 100 determines whether or not the throttle valve 210 is in the WOT state based on the throttle opening instruction value thr (step A12). If the throttle valve 210 is not in the WOT state (step A12: NO), the ECU 100 proceeds to step A14 described above. That is, in this case, the ignition timing is retarded based on the ignition timing instruction value pg determined by the torque demand control logic.

  Here, when it is determined that the throttle valve 210 is in the WOT state as a result of the determination processing in step A12 (step A12: YES), the ECU 100 determines the retard amount DL determined by the torque demand control logic. Is forcibly corrected to zero (step A13), and the process proceeds to step A14. That is, when the processing related to step A13 is performed, the ignition timing retardation control is substantially prohibited, and the ignition timing instruction value pg is controlled according to the base ignition timing instruction value pgbse.

  As described above, according to the ignition timing control process according to the present embodiment, when the throttle valve 210 is in the WOT state, the retard control of the ignition timing is prohibited. Therefore, the maximum acceleration required by the driver is realized without any hindrance, and the drivability is suppressed from being lowered. Further, since the fuel consumption is not deteriorated due to the retard of the ignition timing, the economy is remarkably improved. That is, a decrease in the overall performance of the vehicle is suppressed.

  In FIG. 5, it is determined whether or not the throttle valve 210 is in the WOT state based on the throttle opening instruction value thr. Of course, based on the throttle opening THR detected by the throttle position sensor 212. The determination may be made.

In the present embodiment, when the throttle valve 210 is in the WOT state, retarding the ignition timing is prohibited. That is, according to the flowchart of FIG. 5, even when the vehicle is traveling at a constant speed while the throttle valve 210 is in the WOT state, the retard control of the ignition timing is prohibited, and it is determined whether the vehicle is necessarily accelerating. Not included in the element. However, when the throttle valve 210 is in the WOT state, the engine 200 has a high load regardless of whether it is accelerating or not, and a high output is required. It is thought that it can occur as well as inside. Therefore, by inhibiting the retard control of the ignition timing when the throttle valve 210 is in the WOT state regardless of whether or not the vehicle is accelerating, the deterioration of the overall performance of the vehicle can be suppressed more effectively. Can do. However, it is possible to noticeably reduce the comfort during WOT acceleration. Even if a process for determining whether the vehicle is accelerating is added to the flowchart of FIG. Benefits are enjoyed.
Second Embodiment
In the first embodiment, when the throttle valve is in the WOT state, the retard control of the ignition timing is substantially prohibited and the deterioration of the overall performance of the vehicle is suppressed. It can also be suppressed by a method. Here, a second embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a flowchart of the ignition timing control process according to the second embodiment of the present invention. In the figure, the same reference numerals are assigned to the same parts as those in FIG. 5, and the description thereof is omitted as appropriate.

  In FIG. 6, when the throttle opening instruction value thr and the ignition timing instruction value pg are obtained by the processing related to step A10, the ECU 100 causes the energy loss generated by retarding the ignition timing in the engine 200 (that is, the present invention). A loss energy value Eloss which is an example of such “loss” is acquired (step B10).

  Here, the details of the loss energy value Eloss will be described with reference to FIG. FIG. 7 is a schematic diagram showing the characteristic of the loss energy value Eloss.

  In FIG. 7, the loss energy value Eloss is an illustrated characteristic when the horizontal axis takes the absolute value ΔTr of the negative torque deviation (that is, the torque deviation when the estimated torque Trmes is larger than the target torque Trref). Represented as line PRF_Eloss. That is, the loss energy of the engine 200 increases as the torque deviation increases.

  The value of the loss energy value Eloss has a correlation with the fuel consumption of the engine 200, and the greater the value, the worse the fuel consumption. Therefore, in the present embodiment, the upper limit value Elossth that defines the upper limit of the range in which the deterioration of fuel consumption can be allowed is set. The upper limit value Elossth corresponds to the absolute value ΔTrth of the negative torque deviation. The ECU 100 has a characteristic of loss energy Eloss as shown in FIG. 7, for example, in the form of a map or the like in advance. Note that the negative torque deviation can have a one-to-one relationship with the retard amount DL of the ignition timing when the ECU 100 refers to the torque map 104 as described above.

  Returning to FIG. 6, the ECU 100 acquires the loss energy value Eloss corresponding to the value of the torque deviation output from the adder / subtractor 103 from the map in the process according to step B <b> 10. Next, the ECU 100 determines whether or not the target torque gradient value L is greater than zero (step B11). Here, the details of the target torque gradient value will be described with reference to FIG. FIG. 8 is a schematic diagram conceptually showing a change mode of the target torque Trref.

  In FIG. 8, the vertical axis represents the deviation (that is, the amount of change) of the target torque Trref, and the horizontal axis represents time. That is, on the coordinate plane shown in FIG. 8, the time characteristic of the deviation of the target torque Trref is represented as a straight line. The value of the slope of this straight line is the target torque gradient value L, which is an index value that defines the degree of change in the target torque. Here, the case where the target torque gradient value L is greater than zero indicates a case where a straight line representing the time characteristic of the deviation of the target torque Trref passes through the second or third region shown in the figure. The time for defining the target torque gradient value L (that is, the calculation cycle of the target torque gradient value L) is not particularly limited as long as it does not hinder the operation control of the engine 200.

  Returning to FIG. 6, when the target torque gradient value L is larger than zero (step B11: YES), the ECU 100 further determines whether or not the target torque gradient value L is larger than the threshold value Lth1 (step B13). In FIG. 8, the threshold value Lth1 is a value corresponding to the slope of the boundary line LTH1 (that is, a straight line defining that a change in the target torque ΔTrref1 (ΔTrref1> 0) occurs during the time Ts1, for example) It is an example of a “third threshold” according to the present invention.

  When the target torque gradient value L is larger than the threshold value Lth1 (step B13: YES), that is, a straight line having a gradient corresponding to the target torque gradient value L is the second region in FIG. ECU 100 determines whether or not the loss energy value Eloss acquired in the process according to step B10 is larger than the above-described upper limit value Elossth (step B14). Note that since the ECU 100 has a map in which the loss energy value Eloss and the torque deviation are associated with each other as described above, the determination process itself related to step B14 is executed in the process related to step B10. In that case, only the result of the determination may be referred to in the process according to step B14.

  When the loss energy value Eloss is larger than the upper limit value Elossth (step B14: YES), the ECU 100 corrects the retard amount DL of the ignition timing to be reduced so that the loss energy value Eloss becomes the upper limit value Elossth (step B15). As already described, the loss energy value Eloss is associated with the torque deviation, and the value of the torque deviation is associated with the retardation amount DL by the retardation amount map 104. Therefore, the ECU 100 acquires the retardation amount DL corresponding to the torque deviation value ΔTrth at which the loss energy value Eloss becomes the upper limit value Elossth from the retardation amount map 104, and the retardation amount DL set by the torque demand control logic. (That is, an example of retardation amount reduction correction that is performed so that the loss becomes equal to or less than the upper limit value) in the present invention. When the retard amount DL is corrected to decrease, the ECU 100 proceeds to step A14 and executes ignition timing control.

  On the other hand, when the loss energy value Eloss is equal to or less than the upper limit value Elossth (step B14: NO), the retardation amount DL is not corrected, and the retardation amount DL determined by the torque demand control logic is applied as it is. Shifts to Step A14. That is, when the target torque gradient value L is in the second region, the retard amount DL is corrected to decrease only when the loss energy value Eloss resulting from the retard control of the ignition timing exceeds the upper limit value Elossth, and the comfort level is reduced. As a result, the overall performance of the vehicle is prevented from being lowered.

  On the other hand, when the target torque gradient value L is equal to or less than the upper limit value Lth1 (step B13: NO), that is, when a straight line having a gradient corresponding to the target torque gradient value L exists in the third region in FIG. Regardless of the value of the loss energy Eloss, the retard amount DL is unconditionally corrected to zero, and execution of the retard control of the ignition timing is prohibited (step A13). After the process related to step A13, the process proceeds to step A14. In this case, the ignition timing is controlled to the base ignition timing PGBSE. That is, in this case, since the target torque gradient value is relatively small, priority is given to suppression of deterioration of fuel consumption, assuming that there is no practical decrease in comfort even if the estimated torque Trmes deviates from the target torque Trref. The target torque Trref can be tracked only by controlling the opening degree.

  When it is determined in step B11 that the target torque gradient value L is equal to or less than zero (step B11: NO), the ECU 100 is less than the threshold value Lth2 where the target torque gradient value L is a negative value. Is determined (step B12). Here, the threshold value Lth2 is a value corresponding to the slope of the boundary line LTH2 (that is, a straight line defining that a change in target torque ΔTrref2 (ΔTrref2 <0) occurs during time Ts0) in FIG. And is an example of the “first threshold” according to the present invention. Since the threshold value Lth2 is a negative value, when the absolute value of the target torque gradient value L is larger than the absolute value of the threshold value Lth2, the determination process related to step B12 is “YES”.

  When the target torque gradient value L is less than the threshold value Lth2 (step B12: YES), that is, when a straight line having a gradient corresponding to the target torque gradient value L exists in the fifth region in FIG. If the target torque Trref is greatly reduced, the ECU 100 unconditionally shifts the processing to step A14 without correcting the retard amount DL of the ignition timing. That is, in this case, it is assumed that a relatively large reduction in the target torque Trref has occurred due to a shift request from the AT provided in the vehicle, and drivability is given priority, and the actual torque of the engine 200 is accurately set to the target torque Trref. It is made to follow.

  When the target torque gradient value L is greater than or equal to the threshold value Lth2 (step B12: NO), that is, a straight line having a gradient corresponding to the target torque gradient value L exists in the first region or the fourth region in FIG. If the change in the target torque Trref has not occurred (that is, the target torque gradient value L is zero), the ECU 100 further determines whether or not the target torque gradient value L is less than the threshold value Lth3 (step B16). Here, the threshold value Lth3 is a value corresponding to the slope of the boundary line LTH3 in FIG. 8, and is an example of the “second threshold value” according to the present invention.

  When the target torque gradient value L is greater than or equal to the threshold value Lth3 (step B16: NO), that is, a straight line having a gradient corresponding to the target torque gradient value L exists in the fourth region in FIG. When L is zero, the ECU 100 unconditionally corrects the retardation amount DL to zero regardless of the value of the loss energy Eloss, similarly to the case where the process related to step B13 is “NO”, and Prohibit execution of retard angle control. That is, in conjunction with the third region described above, the retard control of the ignition timing in the engine 200 is prohibited in a range where the target torque gradient value L is relatively small.

  On the other hand, when the target torque gradient value L is less than the threshold value Lth3 (step B16: YES), that is, the straight line having the gradient corresponding to the target torque gradient value L is the first region in FIG. If it is within an example of “first range”, the ECU 100 further determines whether or not the vehicle is decelerating (step B17). When the vehicle is decelerating (step B17: YES), the ECU 100 proceeds to step A14 and, similarly to the case where the process according to step B12 is “YES”, the retard amount DL of the ignition timing. The ignition timing control is executed without correcting any of the above.

  When the vehicle is not decelerating (step B17: NO), the ECU 100 determines whether or not the loss energy value Eloss is larger than the upper limit value Elossth (step B18), similarly to the processing according to step B14. When the loss energy value Eloss is equal to or less than the upper limit value Elossth (step B18: NO), the retardation amount DL is not corrected, and the retardation amount DL determined by the logic of torque demand control is applied as it is, and the process is step. Move to A14.

  On the other hand, when the loss energy value Eloss is larger than the upper limit value Elossth (step B18: YES), the ECU 100 delays the ignition timing so that the loss energy value Eloss becomes the upper limit value Elossth, similarly to the process related to step B15. The angular amount DL is corrected to decrease (step B19). After the processing according to step B19, the ECU 100 shifts the processing to step A14 and executes ignition timing control. That is, when the target torque gradient value L is in the first range, the vehicle is not decelerating, and only when the loss energy value Eloss resulting from the retard control of the ignition timing exceeds the upper limit Elossth. The angular amount DL is corrected to be reduced, and a reduction in the overall performance of the vehicle is suppressed by achieving both comfort and economy. When the process according to step A14 is executed through such various decision branches, the process returns to step A10, and a series of processes is repeated.

  As described above, according to the second embodiment of the present invention, in order to ensure the overall performance of the vehicle, such as the target torque gradient value L and the loss energy value Eloss, or priorities between fuel efficiency and drivability are set. The retard amount DL of the ignition timing is appropriately corrected based on an index value effective for determination (that is, each example of the “predetermined type of operating condition” according to the present invention), for example, a time change of the target torque Trref. In a region where the amount is relatively small, retarding of the ignition timing is prohibited, and in a region where the amount of time change of the target torque Trref is negative and relatively large, the ignition timing is unconditionally retarded. Alternatively, if there is a corresponding change in the target torque Trref that does not belong to them, the ignition timing PG is retarded within a range where the loss energy value Eloss does not exceed the upper limit value Elossth. Therefore, the retard control of the ignition timing can be efficiently executed within a range in which the overall performance of the vehicle is not deteriorated in accordance with the driving condition that changes every moment in the vehicle. That is, it is possible to suppress a decrease in the overall performance of the vehicle when executing the torque demand control.

  The ignition timing control process according to the second embodiment is not contrary to the ignition timing control process according to the first embodiment, and can be executed in cooperation with each other. In FIG. 8, the region where the throttle valve 210 is in the WOT state can be represented as, for example, a WOT region surrounded by a chain line. The WOT region is a part of the second region according to the second embodiment, that is, a region where the retard amount DL of the ignition timing can be corrected to decrease so that the loss energy value Eloss is equal to or less than the upper limit value Elossth. In such a WOT region, as described in the first embodiment, ignition timing retarding control may be substantially prohibited to give priority to improving fuel efficiency. In such a case, since the overall performance of the vehicle can be controlled more precisely, it is possible to more effectively suppress the deterioration of the overall performance.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and the control of the internal combustion engine accompanying such a change. The apparatus is also included in the technical scope of the present invention.

It is a mimetic diagram of an engine system concerning a 1st embodiment of the present invention. FIG. 2 is a block diagram conceptually showing torque demand control logic executed in the engine system of FIG. 1. It is a chart showing transition of the operating state of the engine in the torque demand control of FIG. In FIG. 3, it is a chart showing the transition of the operating state of the engine especially at the time of WOT acceleration. It is a flowchart of the ignition timing control process which ECU performs. 6 is a flowchart of an ignition timing control process according to a second embodiment of the present invention. It is a schematic diagram showing the characteristic of the loss energy value referred in the ignition timing control process of FIG. FIG. 3 is a schematic diagram conceptually showing a change mode of a target torque.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine system, 100 ... ECU, 200 ... Engine, 202 ... Ignition device, 209 ... Air flow meter, 210 ... Throttle valve.

Claims (10)

A control device for an internal combustion engine for controlling the internal combustion engine in a vehicle including the internal combustion engine,
Target torque specifying means for specifying target torque to be output from the internal combustion engine;
Throttle control means for controlling the throttle opening in the internal combustion engine so that the target torque is output;
Actual torque specifying means for specifying the actual torque output from the internal combustion engine;
Retard control means for executing retard control defined as retarding the ignition timing in the internal combustion engine so that the actual torque approaches the target torque when the actual torque is greater than the target torque; ,
Retard angle limiting means for limiting execution of the retard angle control according to a predetermined type of operating condition in the internal combustion engine ;
Torque change specifying means for specifying the degree of change in the target torque as an index value for defining the operating condition;
Comprising
The retard restriction means restricts execution of the retard control according to the degree of change,
The torque change specifying means specifies the degree of change as a target torque gradient value corresponding to a change amount of the target torque per unit time,
The retardation limiting means restricts execution of the retardation control when the target torque gradient value is equal to or greater than a first threshold set in a negative range,
The region less than the first threshold is a region where restriction of execution of the retard angle control is prohibited in order to avoid deterioration of drivability.
A control device for an internal combustion engine. Further comprising transient determining means for determining whether or not the internal combustion engine is in a transient state;
2. The control device for an internal combustion engine according to claim 1, wherein the retard angle limiting unit limits execution of the retard angle control when the determination that the internal combustion engine is in the transient state is made. 3. . The control apparatus for an internal combustion engine according to claim 2, wherein the transient state includes a WOT acceleration state defined as a state where the throttle opening is maximum and the vehicle is accelerating. The control apparatus for an internal combustion engine according to claim 2 or 3, wherein the retard restriction means restricts execution of the retard control by prohibiting execution of the retard control. As an index value that defines the operating condition, further comprising a loss specifying means for specifying a loss of the internal combustion engine due to the execution of the retard control.
5. The delay angle limiting unit limits the execution of the delay angle control by correcting the amount of delay of the ignition timing to be decreased according to the loss. 6. The internal combustion engine control device described. The control apparatus for an internal combustion engine according to claim 5, wherein the retard angle limiting unit limits the execution of the retard angle control when the loss is larger than a predetermined upper limit value. The control apparatus for an internal combustion engine according to claim 6, wherein the retard angle limiting unit limits execution of the retard angle control so that the loss is equal to or less than the upper limit value. The retardation limiting means has a third torque range in which the target torque gradient value is set in the negative range, is equal to or larger than a second threshold value that is larger than the first threshold value, and is set in a positive range. equal to or less than a threshold, if the region is to be prioritized fuel economy than drivability claim 1, characterized in that to limit the execution of the retard control by prohibiting execution of the retard control 7 The control apparatus for an internal combustion engine according to any one of the above. The retardation limiting means is in a first range where the target torque gradient value is in a first range that is greater than or equal to the first threshold and less than the second threshold, and in a second range that is greater than the third threshold. The control apparatus for an internal combustion engine according to claim 8 , wherein execution of the retard control is limited by correcting the retard amount of the ignition timing to be reduced. The retard limiting means is in the range the target torque gradient value is the first, and if the vehicle is not in the deceleration state, to claim 9, characterized in that to limit the execution of the retard control The internal combustion engine control device described.

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