JP2009068430A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To materialize accurate ignition timing control based on torque efficiency without causing increase of calculation load in a control device for an internal combustion engine. <P>SOLUTION: Estimation torque provided when ignition timing is set to MBT under present air quantity condition, and torque efficiency η<SB>b</SB>is calculated from a ratio of target torque and estimation torque. A dimensionless parameter value η<SB>f</SB>determining ignition retardation quantity is set based on the torque efficiency η<SB>b</SB>, and target ignition timing is set based on the dimensionless parameter value η<SB>f</SB>. The dimensionless parameter value η<SB>f</SB>is set one by one to torque efficiency η<SB>b</SB>when torque efficiency η<SB>b</SB>is a predetermined value α or less, and is fixed to a constant value when the torque efficiency η<SB>b</SB>exceeds the predetermined value α. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly to a control device for an internal combustion engine that controls the operation of each actuator based on a target torque.

  Conventionally, as a technology related to torque control of an internal combustion engine, a target torque of the internal combustion engine is set by comprehensively combining the torque requested by the driver and the torque necessary for vehicle control, and the operation instruction value of each actuator is determined based on the target torque. What is determined is known. For example, in Japanese Patent Publication No. 11-509910, the target torque is divided into a fast component and a slow component by a filter, a target value for ignition timing control is set from the component with the fast target torque, and the throttle control is performed from the slow component. A technique for setting a target value is described.

  On the other hand, Japanese Patent Laid-Open No. 2005-113877 discloses a technique that uses the same target torque (required torque) for both ignition timing control and throttle control, instead of dividing the target torque. Specifically, for calculating the target throttle opening degree related to the throttle control, a value obtained by dividing the target torque by the air-fuel ratio efficiency with respect to the torque and the ignition timing efficiency with respect to the torque is used, and the ignition delay amount relating to the ignition timing control is used. Is calculated using the ratio between the target torque and the estimated torque in MBT (hereinafter referred to as torque efficiency).

When comparing the one described in JP-T-11-509910 and the one described in JP-A-2005-113877, the former requires the accuracy of the logic for dividing the target torque. On the other hand, according to the latter, such logic is unnecessary. In other words, once the target air-fuel ratio efficiency and ignition timing efficiency are determined, the throttle opening is determined in accordance with the target torque and the ignition timing is automatically adjusted so as to compensate for the influence of the delay in the air response to the throttle operation. Will be controlled. This is because a delay in air response is reflected on the torque efficiency that determines the ignition retardation amount via the estimated torque.
Japanese National Patent Publication No. 11-509910 JP 2005-113877 A

  However, as described below, there is room for improvement in the technique described in JP-A-2005-113877.

  The estimated torque used for calculating the torque efficiency is based solely on the estimated calculation, and may contain a slight error with respect to the actual torque realized in the MBT. The error in the estimated torque is reflected in the ignition delay amount through the torque efficiency. At this time, if the error is a negative value, the torque efficiency is calculated to be larger than the actual value, so that the ignition retard amount is set smaller than the necessary amount. In that case, knocking may occur due to insufficient retard of the ignition timing, but this can be dealt with by various known knocking controls. For example, an ignition timing at which knocking occurs (knock ignition timing) can be estimated and calculated from the actual air amount, and the ignition timing can be guarded so that it is not advanced from the knock ignition timing.

  On the other hand, if the error of the estimated torque is a positive value, the torque efficiency will be smaller than the actual value, and the ignition retardation amount will be set larger than the required amount. In this case, the torque efficiency does not become 1 even in a situation where the operation at the MBT is required, and as a result, the ignition timing is retarded and the operation at the MBT cannot be realized. End up. In particular, in the vicinity of MBT, the sensitivity of the ignition timing change with respect to the change in torque efficiency is high, and even with a slight deviation in torque efficiency, the ignition timing is greatly shifted to the retard side. Unlike the case where the ignition timing is shifted to the advance side, there is no known technique for preventing the ignition timing from shifting to the retard side and the accompanying deterioration in fuel consumption.

  Therefore, in the inventive process, as a method for preventing the deviation of the ignition timing toward the retarded side, in particular, the deviation from the MBT, the calculated value of the ignition timing obtained from the torque efficiency is directly used as the ignition timing for the ignition device. A proposal has been proposed in which the calculated value is converted into the command value through dead zone logic instead of the command value. The dead zone logic is to set a dead zone in the vicinity of MBT, and to set MBT as a command value when the calculated value of the ignition timing is within the dead zone.

  However, since MBT varies depending on operating conditions such as engine speed and load, the necessary dead band width also varies depending on the operating conditions. For this reason, in order to realize the above plan, the dead zone must be calculated for each operating condition that the internal combustion engine can take, and a complicated dead zone logic with high accuracy is required. That is, in the above plan, the control accuracy of the ignition timing depends on the accuracy of the dead zone logic, and the calculation load of the ECU is increased in exchange for the control accuracy of the ignition timing.

  The present invention has been made in order to solve the above-described problems, and provides a control device for an internal combustion engine that can realize highly accurate ignition timing control based on torque efficiency without causing an increase in calculation load. The purpose is to provide.

In order to achieve the above object, a first invention is a control device for an internal combustion engine,
Target torque setting means for setting the target torque of the internal combustion engine;
Estimated torque calculating means for calculating an estimated torque obtained when the ignition timing is set to MBT under the current air amount condition;
Torque efficiency calculating means for calculating torque efficiency from a ratio between the target torque and the estimated torque;
Ignition delay parameter setting means for setting a dimensionless parameter value for determining the ignition delay amount based on the torque efficiency;
Target ignition timing setting means for setting a target ignition timing based on the dimensionless parameter value and the engine operating condition;
Ignition timing control means for controlling the ignition timing based on the target ignition timing,
The ignition delay parameter setting means sets the dimensionless parameter value in a one-to-one correspondence with the torque efficiency when the torque efficiency is equal to or less than a predetermined value, and sets the dimensionless parameter value when the torque efficiency exceeds a predetermined value. Is fixed to a constant value.

According to a second invention, in the first invention,
The ignition delay parameter setting means fixes the dimensionless parameter value to a value that makes the ignition delay amount zero when the torque efficiency exceeds a predetermined value.

According to a third invention, in the first or second invention,
An upper limit value setting means for setting an upper limit value of the torque efficiency based on a predetermined retardation condition;
The ignition delay parameter setting means sets the dimensionless parameter value based on the smaller one of the torque efficiency and the upper limit value.

4th invention is 1st or 2nd invention,
Limit value setting means for setting an advance side limit value of the dimensionless parameter value based on a predetermined retardation condition,
The ignition retard parameter setting means limits the dimensionless parameter value by the advance side limit value.

The fifth invention is a control device for an internal combustion engine,
Target torque setting means for setting the target torque of the internal combustion engine;
Estimated torque calculating means for calculating an estimated torque obtained when the ignition timing is set to MBT under the current air amount condition;
Torque efficiency calculating means for calculating torque efficiency from a ratio between the target torque and the estimated torque;
Upper limit value setting means for setting an upper limit value of the torque efficiency based on a predetermined retardation condition;
Target ignition timing setting means for setting a target ignition timing based on the smaller one of the torque efficiency and the upper limit value;
Ignition timing control means for controlling the ignition timing based on the target ignition timing;
It is characterized by having.

According to a sixth invention, in the fifth invention,
Target efficiency setting means for setting the target efficiency of the internal combustion engine;
Target air amount setting means for setting a target air amount based on a ratio between the target torque and the target efficiency;
An air amount control means for controlling the air amount based on the target air amount;
The upper limit value setting means sets the target efficiency as the upper limit value.

  According to the first invention, the torque efficiency is converted into a dimensionless parameter value through the dead zone logic, and the target ignition timing is set based on the dimensionless parameter value subjected to the dead zone processing and the engine operating condition. . In this way, if dead zone logic is provided in the conversion logic from torque efficiency to dimensionless parameter value, the dead zone setting can be constant regardless of the engine operating conditions, and the calculation load increases for dead zone calculation. This is prevented.

  According to the second invention, when the torque efficiency exceeds a predetermined value, the dimensionless parameter value is fixed at a value that makes the ignition retardation amount zero, so that the target ignition timing is retarded by the error in torque efficiency. It is possible to prevent the deviation and to reliably set the target ignition timing to MBT.

  According to the third invention, by setting the upper limit value low and limiting the torque efficiency to the upper limit, it is possible to retard the emergency until the ignition timing corresponding to the upper limit value of the torque efficiency. When the torque efficiency is not limited by the upper limit value, the ignition timing control can be performed with priority given to the realization of the target torque.

  According to the fourth invention, by limiting the dimensionless parameter value by the advance side limit value, it is possible to retard the emergency until the ignition timing according to the advance side limit value. When the dimensionless parameter value is not limited by the advance side limit value, the ignition timing control can be performed with priority given to the realization of the target torque.

  According to the fifth aspect, when the torque efficiency is not limited by the upper limit value, the ignition retard amount is set according to the torque efficiency, and the ignition timing control is performed so as to realize the target torque. On the other hand, when the upper limit value is set low and the torque efficiency is limited by the upper limit value, the target ignition timing is advanced at a value corresponding to the upper limit value of the torque efficiency, giving priority to realizing the target torque. Emergency ignition retard can be performed.

  According to the sixth aspect of the invention, since the air amount control is performed based on the ratio between the target torque and the target efficiency, by setting the target efficiency to the upper limit value of the torque efficiency, an emergency is made until the ignition timing according to the target efficiency. In addition to retarding, the amount of air can be increased to compensate for torque reduction due to ignition retard. According to this, although it is temporarily lower than the target torque due to the delay of the air response, the target torque is automatically realized after a while.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a control device for an internal combustion engine as the first embodiment of the present invention. The control device of the present embodiment is applied to a spark ignition internal combustion engine, and is configured as a control device that controls the operation of a throttle and an ignition device that are actuators of the spark ignition internal combustion engine. Hereinafter, the configuration of the control device of the present embodiment will be described with reference to FIG.

  The control device of the present embodiment includes a plurality of calculation elements 2, 4, 6, 8, 10, 12, 14, 18, and 20. Further, a throttle driver 16 for controlling the operation of the throttle and an ignition device driver 22 for controlling the operation of the ignition device are provided. The control device performs calculation according to a predetermined calculation rule by each calculation element 2, 4, 6, 8, 10, 12, 14, 18, 20 based on the input information, and the operation instruction value of each actuator, that is, A target throttle opening and a target ignition timing are calculated. Then, the operation instruction value of each actuator is set in the drivers 16 and 22, and the operation of each actuator is controlled via the drivers 16 and 22.

  The information input to the control device includes various requests from a powertrain manager (not shown) provided at the upper level of the control system and information related to the operating state of the internal combustion engine. The request from the powertrain manager is a request related to the torque of the internal combustion engine and a request related to the efficiency of the internal combustion engine, which are respectively input as numerical values. The required torque includes torque required for vehicle control such as VSC (Vehicle Stability Control system) and TRC (Traction Control System) in addition to the torque requested by the driver. The required efficiency has the meaning of conversion efficiency of heat energy that can be converted into torque, and is a dimensionless parameter that is set on the basis of when the ignition timing is MBT. When it is desired to use thermal energy to raise the exhaust gas temperature for warming up the catalyst, the required efficiency is set to a value smaller than the reference value 1. Also, when it is desired to increase the torque by the advance of the ignition timing, the required efficiency is set to a value smaller than the reference value 1 in order to secure the reserve torque in advance. The operating state information input to the control device includes engine speed, air flow meter output value, throttle opening sensor output value, ignition timing set value, A / F set value, cooling water temperature, intake air temperature. , Valve timing etc. are included.

  Hereinafter, the function of each calculation element 2, 4, 6, 8, 10, 12, 14, 18, 20 and the flow of signal processing between calculation elements will be described.

  The required torque supplied from the powertrain manager is input to the target torque calculator 2. The target torque calculation unit 2 calculates the target torque of the internal combustion engine based on the input requested torque. In the calculation of the target torque, processing such as adding damping torque to the required torque is performed. The calculated target torque is output to a target torque correction unit 10 and a torque efficiency calculation unit 8 which will be described later.

  The required efficiency supplied from the powertrain manager is input to the target efficiency calculation unit 4. The target efficiency calculation unit 4 calculates the target efficiency based on the input required efficiency. Specifically, if there is one type of input required efficiency, it is calculated as the target efficiency. On the other hand, when multiple required efficiencies are input at the same time, for example, when required efficiencies from the viewpoint of catalyst warm-up and required efficiencies for securing reserve torque are input, they are adjusted. Is calculated as the target efficiency. As an arbitration method in this case, for example, minimum value selection can be used. The calculated target efficiency is output to the target torque correction unit 10 described later.

  The estimated torque calculation unit 6 estimates and calculates the torque of the internal combustion engine from the operating state information. More specifically, first, the expected air amount under the current air amount condition is calculated using an air model of the intake system. The air amount condition includes the output value of the throttle opening sensor, the output value of the air flow meter, the valve timing, the intake air temperature, and the like. Next, the expected air amount calculated by the air model is collated with a torque map, and the expected air amount is converted into torque using the torque map. The torque map is a multi-dimensional map with a plurality of parameters including the expected air volume as the axis, and various operating conditions that affect torque such as ignition timing, engine speed, A / F, valve timing, etc. are set as parameters. can do. Values (current values) obtained from current operating state information are input to these parameters. However, the ignition timing is MBT. The estimated torque calculation unit 6 uses the torque converted from the estimated air amount as the estimated torque of the internal combustion engine, and outputs it to the torque efficiency calculation unit 8 described later.

  A target torque and target efficiency are input to the target torque correction unit 10. The target torque correction unit 10 divides and corrects the target torque by the target efficiency, and outputs the corrected target torque to the target air amount calculation unit 12. When the target efficiency is 1, which is a normal value, the target torque calculated by the target torque calculator 2 is output to the target air amount calculator 12 as it is. On the other hand, when the target efficiency is a value smaller than 1, the target torque is raised by division by the target efficiency, and the raised target torque is output to the target air amount calculation unit 12.

  The target air amount calculation unit 12 converts the corrected target torque into an air amount using the air amount map. The air amount map is a multi-dimensional map with a plurality of parameters including the corrected target torque as axes, and various operating conditions that affect the torque, such as ignition timing, engine speed, A / F, valve timing, etc., are used as parameters. Can be set. Values (current values) obtained from current operating state information are input to these parameters. However, the ignition timing is MBT or the reference ignition timing. The target air amount calculation unit 12 sets the air amount converted from the corrected target torque as the target air amount of the internal combustion engine, and outputs it to the throttle opening degree calculation unit 14.

  The throttle opening calculation unit 14 converts the target air amount into the throttle opening using an inverse model of the intake system air model. That is, the throttle opening that can realize the target air amount is calculated. In the inverse model, operating conditions that affect the throttle opening, such as the output value of the air flow meter, valve timing, and intake air temperature, can be set as parameters. Values (current values) obtained from current operating state information are input to these parameters. The throttle opening calculation unit 14 sets the throttle opening converted from the target air amount as the target opening of the throttle, and sets it in the throttle driver 16. The throttle driver 16 controls the throttle so as to realize this target opening.

  The target torque and the estimated torque are input to the torque efficiency calculation unit 8. The torque efficiency calculation unit 8 calculates a ratio between the target torque and the estimated torque, and calculates the calculation result as torque efficiency. In the transient state in which the air amount is changing, the estimated torque changes according to the air amount, and the torque efficiency changes accordingly. However, in the steady state in which the air amount is constant, the estimated torque matches the corrected target torque, and as a result, the torque efficiency matches the target efficiency described above. The torque efficiency calculation unit 8 outputs the calculated torque efficiency to the dead zone processing unit 18.

  The torque efficiency calculated by the torque efficiency calculation unit 8 is subjected to dead band processing by the dead band processing unit 18. Then, the torque efficiency after the dead zone process is input to the ignition timing calculation unit 20. The provision of the dead zone processing unit 18 is one feature of the control device of the present embodiment. The function of the dead zone processing unit 18 and the actions and effects obtained by dead zone processing of the torque efficiency will be described in detail later.

  The ignition timing calculation unit 20 first calculates a retard amount with respect to MBT from the torque efficiency. An ignition timing map is used for calculating the retard amount. The ignition timing map is a multi-dimensional map with a plurality of parameters including torque efficiency as axes, and various operating conditions that affect the determination of the ignition timing, such as the engine speed, can be set as parameters. Values (current values) obtained from current operating state information are input to these parameters. In the ignition timing map, the retard amount is set to a larger value as the torque efficiency is smaller. Then, the target ignition timing is calculated from the retard amount determined from the torque efficiency and the basic ignition timing determined from the operating state of the internal combustion engine. The calculated target ignition timing is set from the ignition timing calculation unit 20 to the ignition device driver 22. The igniter driver 22 controls the igniter according to the target ignition timing.

The function of the dead zone processing unit 18 will be described with reference to FIG. FIG. 2 shows in detail the extracted portion related to the dead zone processing unit 18 in the block diagram of FIG. In FIG. 2, the torque efficiency before the dead zone processing inputted from the torque efficiency calculation unit 8 to the dead zone processing unit 18 is indicated by a symbol “η _b ”, and after the dead zone processing outputted from the dead zone processing unit 18 to the ignition timing map 20. The torque efficiency is indicated by “η _f ”.

In FIG. 2, the relationship between the input value η _b and the output value η _f is shown in a graph in the block of the dead zone processing unit 18. As shown in this graph, while the input value eta _b is smaller than the predetermined value α greater than 0, the output value eta _f is the input value eta input values a linear to _b eta _b is directly output value eta _f Is output as On the other hand, when the input value η _b is equal to or greater than the predetermined value α, the output value η _f is fixed to 1 regardless of the value of the input value η _b . That is, when the input value η _b is between the predetermined value α and 1, a dead zone in which the output value η _f does not change with respect to the change of the input value η _b is obtained.

The operation and effect of the dead zone process for torque efficiency will be described with reference to FIGS. 3 and 4 are graphs showing the relationship between the torque efficiency η _b calculated by the torque efficiency calculation unit 8 and the target ignition timing calculated by the ignition timing calculation unit 20. However, FIG. 3 shows the relationship when the torque efficiency η _b before the dead zone process calculated by the torque efficiency calculation unit 8 is directly input to the ignition timing calculation unit 20. On the other hand, FIG. 4 shows the relationship when the torque efficiency η _f after the dead zone process calculated by the dead zone processor 18 is input to the ignition timing calculator 20.

The torque efficiency η _b is the ratio between the target torque and the estimated torque, but the estimated torque includes an error due to the accuracy of the air model. For this reason, the torque efficiency η _b includes some errors. When the error occurs on the minus side, that is, when the torque efficiency η _b is calculated to be smaller than the original value, the calculated value becomes 1 even if the original value of the torque efficiency η _b is 1. In other words, the error is smaller than 1.

If not carried out dead zone processing on the torque efficiency eta _b, as shown in FIG. 3, the sensitivity of the change of the target ignition timing to a change in torque efficiency eta _b, the torque efficiency eta _b is the target ignition timing approaches 1 MBT It gets higher as you get closer to. For this reason, when the torque efficiency η _b is in the vicinity of 1, even if there is a slight shift due to an error in the torque efficiency η _b , the target ignition timing is shifted to the retard side larger than the MBT. In other words, the target ignition timing cannot be set to MBT in spite of the situation where operation at MBT is required.

In contrast, when carrying out the dead zone processing on the torque efficiency eta _b, as shown in FIG. 4, it torque efficiency eta _b is Until 1 from a predetermined value alpha, the target ignition timing is fixed to the MBT become. This is because the torque efficiency η _f input to the ignition timing calculation unit 20 by the dead zone processing is fixed to 1. According to this, by setting the predetermined value α so as to cover the error of the torque efficiency η _b , even if the torque efficiency is shifted to a value smaller than 1, which is the original value, the target ignition The time can always be set to MBT. Assuming that the error in torque efficiency η _b is about 2 to 3%, the predetermined value α may be set to 0.97.

As described in the section “Problems to be solved by the invention”, in the inventive process, as a method for preventing the deviation of the target ignition timing from the MBT due to the error in the torque efficiency η _b , The following method was considered. The method is that a dead zone logic is interposed between the target ignition timing (calculated value) calculated by the ignition timing calculation unit 20 and the target ignition timing (command value) input to the ignition device driver 22. When the calculated value of the ignition timing is within a predetermined range centered on MBT, the command value is fixed to MBT. Hereinafter, an advantage of performing the dead zone processing on the torque efficiency η _b will be described by comparing with a method of performing the dead zone processing on the target ignition timing itself.

FIG. 5 is a diagram showing the relationship between MBT and engine speed when the load is constant. FIG. 6 is a diagram showing a relationship between MBT and load when the engine speed is constant. As shown in these figures, MBT varies depending on the operating state of the internal combustion engine. Therefore, when the dead zone is set at the target ignition timing with the MBT as the center, the necessary dead zone width also changes depending on the operating state of the internal combustion engine. An example is shown in FIG. FIG. 7 is a graph showing the relationship between the torque efficiency η _b and the target ignition timing when the load is large and when the load is small. As shown in this figure, when the load changes, the relationship between the torque efficiency η _b and the target ignition timing also changes, and the dead zone width centered on MBT changes accordingly. Therefore, in this case, the dead zone must be calculated for each operating condition that the internal combustion engine can take, and a complicated dead zone logic with high accuracy is required.

On the other hand, if a dead zone is set for the torque efficiency η _b , the dead zone width may be set regardless of the engine operating conditions as shown in FIG. This eliminates the need for complicated dead band logic and prevents an increase in the calculation load of the control device for dead band calculation.

Finally, a specific example of the operation realized by the control device of the present embodiment will be described. According to the control device of the present embodiment, the throttle opening and the ignition timing for realizing the target torque can be uniquely determined by setting the target efficiency. For example, when the target torque is 100 Nm, when the target efficiency is set to 1, the corrected target torque is 100 Nm. The target air amount calculation unit 12 and the throttle opening calculation unit 14 calculate the throttle opening that can generate this corrected target torque (100 Nm) by MBT, and set it as the target opening of the throttle. When the air amount becomes constant after changing the throttle opening, the estimated torque calculated by the estimated torque calculation unit 6 is also about 100 Nm. However, the estimated torque is not necessarily 100 Nm due to the influence of the accuracy of the air model, and a value slightly larger than 100 Nm may be calculated. In that case, the torque efficiency η _b, which is the ratio of the target torque and the estimated torque, becomes a value greater than 1, but if it is in the range from the predetermined value α to 1, the dead zone processing causes the ignition timing calculation unit 20 to The input torque efficiency η _f is set to 1. When the torque efficiency η _f is 1, the retard amount calculated by the ignition timing calculation unit 20 is zero, and the target ignition timing is set to MBT.

When the target efficiency is changed to 0.8 at the same target torque, the corrected target torque is 125 Nm. Thereby, the target opening degree of the throttle is increased to an opening degree at which a torque of 125 Nm can be generated by MBT. The estimated torque also changes following the corrected target torque, and is approximately 125 Nm. As a result, the torque efficiency η _b that is the ratio between the target torque and the estimated torque is 0.8. That is, the torque efficiency η _b also changes following the target efficiency. When the torque efficiency η _b is smaller than the predetermined value α, the torque efficiency η _b becomes the torque efficiency η _f inputted to the ignition timing calculation unit 20 as it is, and the target ignition timing is set to a timing delayed from the MBT. Is done. As described above, when the target efficiency is changed to 0.8, a torque-up effect due to an increase in the throttle opening occurs. However, since the ignition timing is retarded at the same time, the torque-up effect is offset by the torque-down effect, and as a result, the torque output from the internal combustion engine is maintained at the target torque. Since the ignition device has high torque responsiveness to its operation, it is possible to reliably cancel the torque increase accompanying the increase in the throttle opening.

In the present embodiment, the target torque calculator 2 corresponds to the “target torque setting means” of the first invention. The estimated torque calculator 6 corresponds to the “estimated torque calculator” of the first invention, and the torque efficiency calculator 8 corresponds to the “torque efficiency calculator” of the first invention. The dead zone processing unit 18 corresponds to the “ignition delay parameter setting means” of the first invention, and the torque efficiency η _f after the dead zone processing corresponds to “a dimensionless parameter value that determines the ignition delay amount”. . The ignition timing calculation unit 20 corresponds to “target ignition timing setting means” of the first invention, and the ignition device driver 22 corresponds to “ignition timing control means” of the first invention.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to the drawings.

  FIG. 8 is a block diagram showing the configuration of the control device for the internal combustion engine as the second embodiment of the present invention. In FIG. 8, elements common to the first embodiment are denoted by the same reference numerals. Hereinafter, the configuration of the control device of the present embodiment will be described with reference to FIG. However, the description of the configuration common to the first embodiment is omitted or simplified, and the configuration different from the first embodiment is mainly described.

  The control apparatus according to the present embodiment has a configuration in which two calculation elements 24 and 26 are combined based on the configuration of the first embodiment. One of them is an upper limit guard value calculation unit 24, and the other is a guard processing unit 26. The upper limit guard value calculation unit 24 calculates the upper limit guard value of torque efficiency based on the operating state information of the internal combustion engine, and outputs it to the guard processing unit 26. The upper guard value calculation unit 24 normally outputs a value (invalid value) greater than 1 as the upper guard value. Only when a predetermined retardation condition is satisfied, an effective upper limit guard value smaller than 1 is output. Here, the retard condition is that the ignition timing must be retarded urgently due to, for example, the occurrence of a knock.

  The guard processing unit 26 receives the torque efficiency calculated by the torque efficiency calculation unit 8 and the upper limit guard value calculated by the upper limit guard value calculation unit 24. The guard processing unit 26 compares the torque efficiency with the upper limit guard value, selects whichever is smaller, and outputs it to the dead zone processing unit 18. For this reason, while an invalid value (a value greater than 1) is input from the upper guard value calculation unit 24, the torque efficiency calculated by the torque efficiency calculation unit 8 is output to the dead zone processing unit 18 as it is. Become. On the other hand, when an effective value (a value smaller than 1) is input from the upper limit guard value calculation unit 24, the torque efficiency limited by the upper limit guard value is output to the dead zone processing unit 18.

  FIG. 9 is a time chart showing a specific example of the operation realized by the control device of the present embodiment. When the upper limit guard value is set to a value larger than 1 (invalid value), the target ignition timing is set according to the torque efficiency calculated by the torque efficiency calculation unit 8. In this case, the actual torque output from the internal combustion engine is maintained at the target torque.

  When the predetermined retardation condition is satisfied, the upper limit guard value is set to a value (effective value) smaller than 1. As a result, the torque efficiency input to the ignition timing calculator 20 is forcibly limited by the upper limit guard value, and the target ignition timing is immediately retarded until the ignition timing corresponding to the upper limit guard value. According to this, even when knocking occurs, knocking can be quickly avoided by the effect of an emergency ignition delay. However, in this case, since the target ignition timing is set to the retard side from the ignition timing determined from the torque efficiency, it is inevitable that the actual torque output from the internal combustion engine becomes lower than the target torque.

  On the other hand, if the ignition timing is simply retarded, it can also be realized by lowering the target efficiency. By reducing the target efficiency, it is possible to retard the ignition while realizing the target torque. However, there is a slight time lag due to a delay in the air response from when the target efficiency is lowered to when the torque efficiency is lowered. For this reason, it is difficult to perform an emergency ignition delay even if the target efficiency is lowered.

  Therefore, the control device of the present embodiment selects the ignition delay method depending on which of the emergency ignition retard and the target torque is prioritized. Specifically, when priority is given to an emergency ignition delay, the ignition retard is performed by setting the upper limit guard value to an effective value and limiting the upper limit of the torque efficiency. According to this, a reliable emergency retardation is possible when a knock occurs.

  On the other hand, when priority is given to the realization of the target torque, the ignition retard is performed by lowering the target efficiency while the upper limit guard value is set to an invalid value. According to this, it is possible to realize an ignition retardation that does not require an emergency for warming up the catalyst or the like while maintaining the target torque.

  In the present embodiment, the target torque calculator 2 corresponds to the “target torque setting means” of the fifth invention. The estimated torque calculator 6 corresponds to the “estimated torque calculator” of the fifth invention, and the torque efficiency calculator 8 corresponds to the “torque efficiency calculator” of the fifth invention. The upper guard value calculation unit 24 corresponds to the “upper limit setting means” of the fifth invention, and the “target ignition timing setting unit” of the fifth invention is formed by the guard processing unit 26, dead zone processing unit 18 and ignition timing calculation unit 20. Means "are configured. The ignition device driver 22 corresponds to the “ignition timing control means” of the fifth invention. Further, in the present embodiment, the upper limit guard value calculation unit 24 corresponds to the “upper limit setting means” of the third invention, and the guard processing unit 26 and the dead zone processing unit 18 perform the “ignition delay” of the third invention. An “angular parameter setting means” is also configured.

  By the way, the control device of the present embodiment can be implemented with its characteristic portions modified as shown in FIG. In the modification shown in FIG. 10, a guard processing unit 26 is moved between the dead zone processing unit 18 and the ignition timing calculation unit 20. In this configuration, the guard processing unit 26 is input with the torque efficiency subjected to the dead band processing by the dead band processing unit 18 and the upper limit guard value calculated by the upper limit guard value calculation unit 24. The guard processing unit 26 compares the torque efficiency that has been subjected to the dead zone processing and the upper limit guard value, selects one of the smaller ones, and outputs it to the ignition timing calculation unit 20.

  Even when such a configuration is adopted, the same effect as that obtained by the configuration shown in FIG. 8 can be obtained. However, in the configuration shown in FIG. 10, the upper limit guard value calculation unit 24 corresponds to the “limit value setting unit” of the fourth invention, and the guard processing unit 26 corresponds to the “ignition retarding parameter setting unit” of the fourth invention. Equivalent to.

Embodiment 3 FIG.
Next, Embodiment 3 of the present invention will be described with reference to the drawings.

  FIG. 11 is a block diagram showing a configuration of a control device for an internal combustion engine as the third embodiment of the present invention. In FIG. 11, elements common to the second embodiment are denoted by the same reference numerals. Hereinafter, the configuration of the control device of the present embodiment will be described with reference to FIG. However, the description of the configuration common to the second embodiment is omitted or simplified, and the configuration different from the second embodiment is mainly described.

  The control device of the present embodiment includes two required efficiency calculation units 30 and 32 and one arbitration unit 34 as calculation elements related to calculation of target efficiency. One required efficiency calculation unit 30 determines the necessity of catalyst warm-up based on signals from an exhaust temperature sensor, a catalyst temperature sensor, etc., and calculates the required efficiency for catalyst warm-up based on the determination result. ing. The other required efficiency calculation unit 32 determines the necessity of avoidance of knock based on the signal of the knock sensor and the like, and calculates the required efficiency for avoiding knock based on the determination result. Of the required efficiencies calculated by the required efficiency calculating units 30 and 32, the smaller one is selected by the arbitrating unit 34 and output to the target torque correcting unit 10 as the target efficiency.

  In the control device of the present embodiment, the target efficiency is associated with the upper limit guard value used in the guard processing unit 26. Specifically, the required efficiency for knock avoidance calculated by the required efficiency calculation unit 32 is input to the arbitration unit 34 and also to the guard processing unit 26. That is, in this embodiment, the required efficiency for avoiding knock is used as it is as the upper limit guard value. On the other hand, the required efficiency for catalyst warm-up calculated by the required efficiency calculation unit 30 is input only to the arbitration unit 34.

  According to such a configuration, the ignition timing can be controlled by an optimum method corresponding to the urgency of the ignition delay. Hereinafter, in the control device of the present embodiment, when only catalyst warm-up is required, when only knock avoidance is required, or when both catalyst warm-up and knock avoidance are required, ignition timing control is performed. An outline will be described.

  First, when only catalyst warm-up that does not require an emergency delay is required, a value (effective value) smaller than 1 is set as the required efficiency for catalyst warm-up, and the required efficiency for avoiding knock is A value greater than 1 (invalid value) is set. In this case, the required efficiency for catalyst warm-up is selected as the target efficiency. In this case, an invalid value is set as the upper limit guard value, and the torque efficiency calculated by the torque efficiency calculation unit 8 is input to the dead zone processing unit 18 as it is. Since the amount of air is reflected in the estimated torque used for calculating the torque efficiency, the target ignition timing is gradually retarded following the increase in the amount of air. According to this, it is possible to realize the ignition delay necessary for warming up the catalyst while maintaining the target torque.

  Next, when only knock avoidance requiring emergency retard is requested, an effective value is set for the required efficiency for avoiding knock, and an invalid value is set for the required efficiency for catalyst warm-up. In this case, the required efficiency for avoiding knock is selected as the target efficiency. Further, the required efficiency for avoiding knock is also input to the guard processing unit 26 as an upper limit guard value, so that the torque efficiency limited to the upper limit is input to the dead zone processing unit 18. As a result, the target ignition timing is immediately retarded to the ignition timing corresponding to the upper limit guard value (required efficiency for avoiding knock). Further, in this case, the air amount is controlled so that the required efficiency for avoiding knock is the target efficiency, so that the air amount can be increased so as to compensate for the torque reduction due to the emergency ignition delay. According to this, although the actual torque is temporarily lower than the target torque due to the delay of the air response, the target torque is automatically realized after a while.

  When both catalyst warm-up and knock avoidance are required, both the required efficiency for knock avoidance and the required efficiency for catalyst warm-up are set to valid values, and the smaller value of the two required efficiencies is the target. Selected as efficiency. If the required efficiency for avoiding knock is smaller, the required efficiency for avoiding knock is selected as the target efficiency. The ignition timing control in this case is the same as the ignition timing control when only knock avoidance is required.

  On the other hand, if the required efficiency for catalyst warm-up is smaller than the required efficiency for avoiding knocks, the air volume control is performed with the required efficiency for catalyst warm-up as the target efficiency, and eventually the torque The torque efficiency calculated by the efficiency calculation unit 8 matches the required efficiency for catalyst warm-up. On the other hand, the required efficiency for avoiding knock is input to the guard processing unit 26 as an upper limit guard value, whereby the ignition retard amount is calculated based on the torque efficiency limited by the upper limit. As a result, the target ignition timing is temporarily retarded to the ignition timing that corresponds to the required efficiency for avoiding knocking temporarily, and then the required efficiency for catalyst warm-up is achieved while following the increase in the air amount. The ignition timing is gradually retarded until the corresponding ignition timing.

  Also in the control apparatus of the present embodiment, a part of the configuration shown in FIG. 11 can be modified as shown in FIG. In other words, the guard processing unit 26 arranged between the guard processing unit 8 and the dead zone processing unit 18 can be moved between the dead zone processing unit 18 and the ignition timing calculation unit 20.

  In the present embodiment, the required efficiency calculation unit 32 corresponds to the “target efficiency setting means” of the sixth invention, and the required efficiency for avoiding knock corresponds to the “target efficiency” of the sixth invention. Yes. The target torque correction unit 10 and the target air amount calculation unit 12 constitute the “target air amount setting means” according to the sixth aspect of the invention. The throttle opening degree calculation unit 14 and the throttle driver 16 constitute the “air” according to the sixth aspect of the invention. The “quantity control means” is configured.

Others.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the following modifications may be made.

  In each embodiment, the dimensionless parameter value (ignition delay parameter value) used for calculation of the ignition retard amount only needs to be converted from the torque efficiency according to a certain rule. The rule is that when the torque efficiency is less than the predetermined value α, the ignition delay parameter value is set in a one-to-one correspondence with the torque efficiency, and when the torque efficiency exceeds the predetermined value α, the ignition delay parameter value is fixed to a constant value. It is to do. If the constant value is a value that makes the ignition retardation amount zero, the target ignition timing can be reliably set to MBT in a situation where the torque efficiency exceeds the predetermined value α.

  In each embodiment, a variable valve lift amount device that changes the maximum lift amount of the intake valve may be used instead of the throttle as an actuator for controlling the air amount. In this case, it is necessary to change the configuration in the control device, but instead of the throttle opening calculation unit 14, a calculation element for calculating the maximum lift amount of the intake valve from the target air amount may be arranged.

It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 1 of this invention. It is the figure which extracted and showed in detail the part relevant to a dead zone process part in the block diagram of FIG. It is a graph which shows the relationship between torque efficiency (eta) _b and target ignition timing at the time of calculating target ignition timing based on torque efficiency (eta) _b before a dead zone process. It is a graph which shows the relationship between torque efficiency (eta) _b and target ignition timing in the case of calculating target ignition timing based on torque efficiency (eta) _f after a dead zone process. It is a figure which shows the relationship between MBT and engine speed when making load constant. It is a figure which shows the relationship between MBT and load when an engine speed is made constant. It is a figure which compares and shows the relationship between torque efficiency (eta) _b and target ignition timing with the case where load is large, and when it is small. It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 2 of this invention. It is a time chart which shows the specific example of the operation | movement implement | achieved by the structure shown in FIG. It is a block diagram which shows the modification of the characteristic part of the structure shown in FIG. It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 3 of this invention.

Explanation of symbols

2 Target torque calculator 4 Target efficiency calculator 6 Estimated torque calculator 8 Torque efficiency calculator 10 Target torque corrector 12 Target air amount calculator 14 Throttle opening calculator 16 Throttle driver 18 Dead band processor 20 Ignition timing calculator 22 Ignition device driver 24 Upper limit guard value calculation unit 26 Guard processing unit 30 Required efficiency calculation unit 32 for catalyst warm-up Required efficiency calculation unit 34 for knock avoidance Arbitration unit

Claims (6)

Target torque setting means for setting the target torque of the internal combustion engine;
Estimated torque calculating means for calculating an estimated torque obtained when the ignition timing is set to MBT under the current air amount condition;
Torque efficiency calculating means for calculating torque efficiency from a ratio between the target torque and the estimated torque;
Ignition delay parameter setting means for setting a dimensionless parameter value for determining the ignition delay amount based on the torque efficiency;
Target ignition timing setting means for setting a target ignition timing based on the dimensionless parameter value and the engine operating condition;
Ignition timing control means for controlling the ignition timing based on the target ignition timing,
The ignition delay parameter setting means sets the dimensionless parameter value in a one-to-one correspondence with the torque efficiency when the torque efficiency is equal to or less than a predetermined value, and sets the dimensionless parameter value when the torque efficiency exceeds a predetermined value. Is fixed to a constant value.   2. The control of an internal combustion engine according to claim 1, wherein the ignition delay parameter setting means fixes the dimensionless parameter value to a value that makes an ignition delay amount zero when the torque efficiency exceeds a predetermined value. apparatus. An upper limit value setting means for setting an upper limit value of the torque efficiency based on a predetermined retardation condition;
3. The control of the internal combustion engine according to claim 1, wherein the ignition delay parameter setting unit sets the dimensionless parameter value based on a smaller one of the torque efficiency and the upper limit value. apparatus. Limit value setting means for setting an advance side limit value of the dimensionless parameter value based on a predetermined retardation condition,
3. The control apparatus for an internal combustion engine according to claim 1, wherein the ignition delay parameter setting means limits the dimensionless parameter value by the advance side limit value. Target torque setting means for setting the target torque of the internal combustion engine;
Estimated torque calculating means for calculating an estimated torque obtained when the ignition timing is set to MBT under the current air amount condition;
Torque efficiency calculating means for calculating torque efficiency from a ratio between the target torque and the estimated torque;
Upper limit value setting means for setting an upper limit value of the torque efficiency based on a predetermined retardation condition;
Target ignition timing setting means for setting a target ignition timing based on the smaller one of the torque efficiency and the upper limit value;
Ignition timing control means for controlling the ignition timing based on the target ignition timing;
A control device for an internal combustion engine, comprising: Target efficiency setting means for setting the target efficiency of the internal combustion engine;
Target air amount setting means for setting a target air amount based on a ratio between the target torque and the target efficiency;
An air amount control means for controlling the air amount based on the target air amount;
6. The control apparatus for an internal combustion engine according to claim 5, wherein the upper limit value setting means sets the target efficiency as the upper limit value.

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