JP4499809B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine, and in particular, a target torque is set according to a request of a driver (driver), and a torque output from the internal combustion engine is adjusted in accordance with the target torque. The present invention relates to a control device for an internal combustion engine for controlling the internal combustion engine.

  In recent years, the engine output shaft torque, which is a physical quantity that directly affects vehicle control, is used as a required value of driving force from the driver and each vehicle system (automatic transmission control, brake control, traction control, etc.). As a target value, the engine control amount of air, fuel amount, and ignition timing are determined, and the actual output torque is estimated from the actual engine state and transmitted to each vehicle system to achieve cooperative control. In addition, a technique for obtaining good running performance, so-called torque base control has been proposed.

  In such control, it is important to calculate the actual output torque of the engine with high accuracy and achieve the target output torque with high accuracy. For example, Patent Document 1 discloses a method for improving torque controllability without increasing the number of maps when obtaining the output torque of an internal combustion engine in response to a driver's request. More specifically, loss torque and ISC torque are added to the driver request shaft torque calculated from the accelerator opening, and after the ignition timing efficiency correction and target A / F efficiency correction, torque-air amount conversion processing is performed. The coefficient for correcting the ignition timing efficiency is calculated with a small number of maps.

  Patent Document 2 discloses a method for accurately estimating the actual output torque of the engine with a small control map and for accurately realizing the engine control amount for realizing the target output torque with a simple logic configuration. Has been. More specifically, the relationship between the charging efficiency, the ignition timing, and the output torque is approximated by a quadratic function, the actual output torque is calculated from the charging efficiency and the ignition timing, and the charging that is the ratio between the charging efficiency and the actual output torque is calculated. The target intake air amount is calculated from the target output torque using the efficiency-torque conversion coefficient. The engine output is calculated with a simple logic configuration by calculating the actual output torque from the charging efficiency and calculating the target intake air amount from the target output torque based on the ratio thereof.

JP 2003-301766 A Japanese Patent Application No. 2007-310968

  The methods of Patent Document 1 and Patent Document 2 convert the control amount from the target output torque to the target intake air amount in consideration of the ignition timing in order to achieve the target output torque with high accuracy. However, it does not show a countermeasure when the target output torque cannot be achieved. First, the output torque characteristics of the internal combustion engine will be described with reference to FIG. FIG. 13 is a graph showing the relationship between charging efficiency and output torque. The higher the charging efficiency, the higher the actual output torque, and the higher the charging efficiency, the larger the amount of decrease in the actual output torque due to the ignition retard. That is, when the charging efficiency is increased in the ignition retarded state, the actual output torque does not increase at a certain operating point. According to the output torque characteristics of these internal combustion engines, when the target output torque is increased with ignition retarded by, for example, knock control, the target charging efficiency increases to achieve the target output torque. Even if the charging efficiency increases at a point, the actual output torque does not increase. At this time, the actual output torque cannot achieve the target output torque, but the target intake air amount may continue to increase to achieve the target charging efficiency. As a result, although the actual output torque does not increase any more, the throttle opening continues to open excessively, the actual intake air amount continues to increase excessively, and the fuel injection amount according to the intake air amount Therefore, there is a problem that the fuel consumption may be deteriorated. In addition, when the target output torque is decreased after the target intake air amount continues to increase excessively, the response to the decrease direction of the actual output torque may deteriorate because the throttle opening is excessively opened. There was a problem of concern.

  The present invention has been made to solve such a problem, and by effectively limiting the target charging efficiency to an appropriate maximum target charging efficiency based on the operating state of the internal combustion engine, it is possible to effectively avoid deterioration of fuel consumption. It is an object of the present invention to provide a control device for an internal combustion engine that can improve control performance.

  The present invention relates to throttle opening control means for performing variable control of the intake air flow rate by changing the opening area of the intake passage by controlling the opening of a throttle provided in the intake passage of the internal combustion engine, and Driver request output calculation means for calculating a driver request output for the vehicle based on the driving state and / or the traveling speed of the vehicle and the accelerator operation state of the driver, and a target to be generated by the internal combustion engine based on the driver request output A target output torque calculating means for calculating an output torque or a target average effective pressure, a basic target ignition timing is calculated based on an operating state of the internal combustion engine, and an engine temperature of the internal combustion engine is calculated with respect to the calculated basic target ignition timing. And / or intake air temperature correction, retard correction for early activation of the catalyst, and / or retard correction by knock control Target ignition timing calculation means for calculating the ignition timing, and actual output torque calculation means for calculating the actual output torque or the actual average effective pressure of the internal combustion engine based on at least the engine speed, the actual charging efficiency, and the target ignition timing And target charging efficiency calculating means for calculating a target charging efficiency based on the actual charging efficiency, the actual output torque or actual average effective pressure, and the target output torque or target average effective pressure, and at least the engine rotation A maximum target charging efficiency calculating means for calculating a maximum target charging efficiency for limiting the target charging efficiency based on the number and an ignition retard amount that is a difference between the target ignition timing and the basic target ignition timing; The target filling efficiency calculated by the target filling efficiency calculation means is compared with the maximum target filling efficiency calculated by the maximum target filling efficiency calculation means, Selecting a value of which one is the limit, and outputting the target filling efficiency that has been subjected to the restriction processing, and calculating the target cylinder air amount based on the target filling efficiency that has been subjected to the restriction processing that is output from the restriction means, The target intake air amount calculating means for calculating the target intake air amount that the internal combustion engine should inhale from the target cylinder air amount, and the target intake air amount calculated by the target intake air amount calculating means And a control means for controlling the throttle opening degree control means to control the throttle opening degree.

  The present invention relates to throttle opening control means for performing variable control of the intake air flow rate by changing the opening area of the intake passage by controlling the opening of a throttle provided in the intake passage of the internal combustion engine, and Driver request output calculation means for calculating a driver request output for the vehicle based on the driving state and / or the traveling speed of the vehicle and the accelerator operation state of the driver, and a target to be generated by the internal combustion engine based on the driver request output A target output torque calculating means for calculating an output torque or a target average effective pressure, a basic target ignition timing is calculated based on an operating state of the internal combustion engine, and an engine temperature of the internal combustion engine is calculated with respect to the calculated basic target ignition timing. And / or intake air temperature correction, retard correction for early activation of the catalyst, and / or retard correction by knock control Target ignition timing calculation means for calculating the ignition timing, and actual output torque calculation means for calculating the actual output torque or the actual average effective pressure of the internal combustion engine based on at least the engine speed, the actual charging efficiency, and the target ignition timing And target charging efficiency calculating means for calculating a target charging efficiency based on the actual charging efficiency, the actual output torque or actual average effective pressure, and the target output torque or target average effective pressure, and at least the engine rotation A maximum target charging efficiency calculating means for calculating a maximum target charging efficiency for limiting the target charging efficiency based on the number and an ignition retard amount that is a difference between the target ignition timing and the basic target ignition timing; The target filling efficiency calculated by the target filling efficiency calculation means is compared with the maximum target filling efficiency calculated by the maximum target filling efficiency calculation means, Selecting a value of which one is the limit, and outputting the target filling efficiency that has been subjected to the restriction processing, and calculating the target cylinder air amount based on the target filling efficiency that has been subjected to the restriction processing that is output from the restriction means, The target intake air amount calculating means for calculating the target intake air amount that the internal combustion engine should inhale from the target cylinder air amount, and the target intake air amount calculated by the target intake air amount calculating means Since the control device for the internal combustion engine includes the control means for controlling the throttle opening degree control means to control the throttle opening degree, the target charging efficiency is set to an appropriate maximum target charging efficiency based on the operating state of the internal combustion engine. By limiting, deterioration of fuel efficiency can be effectively avoided and control performance can be improved.

Embodiment 1 FIG.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. As the internal combustion engine in the present embodiment, a gasoline engine is assumed. 1 and 2 are configuration diagrams schematically showing an engine and an engine control unit that controls the engine according to Embodiment 1 of the present invention.

  In FIG. 1, 1 is an engine, 2 is an electronically controlled throttle valve, 3 is a throttle opening sensor, 5 is a surge tank, 6 is an intake manifold pressure sensor (intake manifold pressure sensor), 7 is an EGR valve, 8 is an injector, Is an ignition coil, 10 is a spark plug, and 11 is a crank angle sensor.

  As shown in FIG. 1, an electronically controlled throttle valve 2 that is electronically controlled to adjust the intake air flow rate is provided upstream of an intake system (intake passage) provided for the engine 1. Yes. The electronically controlled throttle valve 2 is provided with a throttle opening sensor 3 in order to measure the opening thereof. Further, an air flow sensor 4 for measuring the intake air flow rate is provided upstream of the electronically controlled throttle valve 2, and a part of the intake system (intake passage) downstream of the electronically controlled throttle valve 2 is connected to the engine 1. Before this point, the inner diameter is larger than that of the other portions, and the surge tank 5 is configured. The surge tank 5 is provided with an intake manifold pressure sensor 6 for measuring the pressure in the surge tank 5.

  Note that both the airflow sensor 4 and the intake manifold pressure sensor 6 may be provided, or only one of them may be provided.

  Further, an electronically controlled EGR valve 7 is connected to the lower part of the surge tank 5. An injector 8 for injecting fuel is provided in the intake system (intake passage) downstream of the surge tank 5. The injector 8 may be provided so that it can be directly injected into the cylinder of the engine 1. Further, the engine 1 includes an ignition coil 9 and a spark plug 10 for igniting an air-fuel mixture in a cylinder of the engine 1, and a plate provided on a crankshaft for detecting the rotational speed and crank angle of the engine. A crank angle sensor 11 for detecting an edge is provided.

  In FIG. 2, 12 is an accelerator opening sensor, and 13 is an electronic control unit (hereinafter referred to as “ECU”). Since other configurations are the same as those in FIG. 1, the same reference numerals are given, and description thereof is omitted here. The intake air flow rate measured by the airflow sensor 4, the intake manifold pressure measured by the intake manifold pressure sensor 6, the opening of the electronically controlled throttle valve 2 measured by the throttle opening sensor 3, and the output from the crank angle sensor 11 The pulse synchronized with the edge of the plate provided on the crankshaft is input to the ECU 13. In addition, the measured value is input to the ECU 13 from the accelerator opening sensor 12 other than the above and other various sensors, and further from other controllers (for example, control systems such as automatic transmission control, brake control, traction control). A torque request value is also input. The ECU 13 calculates the actual output torque based on various input data using a method described later, and based on the accelerator opening, the operating state of the engine, and a torque request value from another controller. The target output torque (or target average effective pressure) is set. A target intake air flow rate and a target ignition timing are calculated using a method to be described later so as to achieve the set target output torque, and the electronically controlled throttle valve 2 is controlled to achieve the target intake air flow rate. The ignition coil 9 is energized to achieve the above. Further, the opening degree of the electronically controlled EGR valve 7 is controlled according to the operating state, and the injector 8 is driven so as to achieve the target air-fuel ratio. Further, command values for various actuators other than those described above are also calculated.

  Next, an overview of torque base control performed in the ECU 13 will be described with reference to FIG. FIG. 3 is a schematic diagram showing the overall configuration of the torque base control. In FIG. 3, 14 is a torque control unit, 15 is a torque interface unit (hereinafter referred to as “torque I / F unit”), and 16 is an engine control unit. The engine control unit 16 includes an intake air amount control unit 16a, a fuel control unit 16b, an ignition timing control unit 16c, and another control unit 16d.

  The torque control unit 14 calculates the target output torque (or target average effective pressure) from the accelerator opening measured by the accelerator opening sensor 12 and the torque request from another controller, and sends it to the torque I / F unit 15. Sent.

  The torque I / F unit 15 performs an interconversion process between torque and charging efficiency and an interconversion process between torque and ignition timing to calculate an actual output torque, and calculates a target charging efficiency and a target ignition timing. The actual output torque is sent to the torque control unit 14, and the target charging efficiency and target ignition timing are sent to the engine control unit 16.

  The intake air amount control unit 16a of the engine control unit 16 calculates the target cylinder intake air amount from the target charging efficiency, and further calculates the target intake air amount. The engine control unit 16 feedback-controls the electronically controlled throttle valve 2 using the airflow sensor 4 and the intake manifold pressure sensor 6 so as to achieve the calculated target intake air amount with high accuracy. Further, the cylinder intake amount is estimated from the intake air flow rate measured by the airflow sensor 4 and the actual charging efficiency is also calculated. The fuel control unit 16b calculates the fuel injection amount for achieving the target air-fuel ratio using the actual charging efficiency calculated by the intake air amount control unit 16a, and drives the injector 8. The ignition timing control unit 16 c calculates the basic ignition timing using the actual charging efficiency calculated by the intake air amount control unit 16 a and outputs the basic ignition timing to the torque I / F unit 15. After the final target ignition timing is calculated by the torque I / F unit 15, the calculated target ignition timing is sent to the ignition timing control unit 16c again, and the ignition coil 9 is energized. In addition to these, the control unit 16d also performs control of the EGR valve opening, processing such as OBD, communication, and the like. With such a configuration, it is possible to accurately respond to the driver's requested output and torque requests from other controls.

  Next, the torque control unit 14 will be described in detail with reference to FIG. FIG. 4 is a diagram illustrating a configuration of the torque control unit according to the first embodiment. As shown in FIG. 4, the torque controller 14 includes a driver request torque calculator B101, an ISC request torque calculator B102, a vehicle request torque calculator B103, a first target output torque calculator B104, 2 target output torque calculator B105. B116 is a second actual output torque calculator provided in the torque I / F unit 15.

  In the driver request torque calculation unit B101, the driver request torque is calculated from the accelerator opening measured by the accelerator opening sensor 12 and the driving state of the engine such as the engine speed or the running state of the vehicle such as the vehicle speed. Next, in the ISC required torque calculation unit B102, the ISC required torque is calculated based on the engine rotational speed, the engine water temperature, the switch information (hereinafter referred to as SW information) of the engine accessory load, and the like. Note that the ISC required torque may be calculated based on the engine oil temperature instead of the engine water temperature. The ISC required torque includes engine friction loss torque, pumping loss torque, and engine accessory load torque, and is necessary torque to maintain the ISC target engine speed. The vehicle required torque calculation unit B103 calculates the required torque from other controllers such as brake control, stability control, and automatic transmission control, and the second actual output torque calculation unit B116 of the torque I / F unit 15. The vehicle request torque is calculated based on the second actual output torque corresponding to the torque actually output from the engine. Further, when torque requests from a plurality of controllers are overlapped, the vehicle request torque is calculated by performing torque arbitration that prioritizes torque requests that are important for ensuring vehicle safety, such as brake control.

  In the first target output torque calculation unit B104, the torque controlled by the intake air amount among the driver request torque calculated by the driver request torque calculation unit B101 and the ISC request torque calculated by the ISC request torque calculation unit B102, Calculated as the first target output torque. The first target output torque calculation unit B104 calculates the target average effective pressure of the internal combustion engine from the driver request torque calculated by the driver request torque calculation unit B101 instead of the first target output torque. Also good. In the second target output torque calculation unit B105, the torque controlled by the ignition timing among the vehicle request torque calculated by the vehicle request torque calculation unit B103 and the ISC request torque calculated by the ISC request torque calculation unit B102, Calculated as the second target output torque. The second target output torque is a required torque that needs to change instantaneously, such as a vehicle request torque or an engine accessory load torque, whereas the first target output torque is a driver request torque or an engine This is a required torque having a large torque change range, such as friction loss torque, or a required torque that may be slow even if the change speed is slow. Further, the first target output torque and the second target output torque are monitored with each other, and a torque limit is provided so as not to make a sudden torque change beyond a preset reference value. When there is no torque request from the vehicle side, the second target output torque is set to the same value as the first target output torque. A predetermined value such as zero or a maximum torque value may be entered.

  Next, the torque I / F unit 15 and the engine control unit 16 will be described in detail with reference to FIG. FIG. 5 is a diagram showing the configuration of the torque I / F unit 15 and the engine control unit 16 according to the first embodiment. In addition, about the torque control part 14, only the part required for the following description is shown in figure, and the whole structure is as having shown in FIG.

  As shown in FIG. 5, the torque I / F unit 15 includes a first actual output torque calculation unit B106, a charging efficiency-torque conversion coefficient calculation unit B107, a first target charging efficiency calculation unit B108, and a maximum target. A charging efficiency calculation unit B109, a second target charging efficiency calculation unit B110, a second target ignition timing calculation unit B111, a second actual output torque calculation unit B116, and a first target output torque correction calculation unit B117 And a third actual output torque calculation unit B118.

  The engine control unit 16 includes a target throttle opening calculation unit B112, an actual charging efficiency calculation unit B113, a first target ignition timing calculation unit B114, and a final target ignition timing calculation unit B115.

  In the first actual output torque calculator B106, the actual charging efficiency calculated by the actual charging efficiency calculator B113 and the first target ignition timing calculated by the first target ignition timing calculator B114 are used. The first actual output torque is calculated. A method for calculating the actual output torque will be described later. Note that the first actual output torque calculation unit B106 may calculate the actual average effective pressure from the actual charging efficiency and the first target ignition timing instead of the actual output torque. In the charging efficiency-torque conversion coefficient calculating unit B107, the first actual output torque calculated by the first actual output torque calculating unit B106 and the actual charging efficiency calculated by the actual charging efficiency calculating unit B113 described later are used. From the ratio, a charging efficiency-torque conversion coefficient is calculated, and a filtering process for smoothing is performed. It should be noted that the filter constant used for the filter processing can be switched between idle operation and off-idle operation to achieve both stability during idle operation and responsiveness during off-idle operation. This charging efficiency-torque conversion coefficient is a coefficient that correlates with the thermal efficiency under the current operating conditions, and is a substantially constant value in the entire region except when the ignition timing is set to the retard side extremely. In addition, when the engine is started, the filling efficiency-torque conversion coefficient is given as a predetermined value determined by the engine water temperature or the engine oil temperature at the time of starting the engine, whereby engine stall can be prevented and startability is improved.

  In the first target charging efficiency calculation unit B108, the first target output torque calculated by the first target output torque calculation unit B104 of the torque control unit 14 is calculated by the charging efficiency-torque conversion coefficient calculation unit B107. The first target charging efficiency is calculated by multiplying the charging efficiency-torque conversion coefficient. Thus, by using the charging efficiency-torque conversion coefficient, mutual conversion between torque and charging efficiency is performed by a simple calculation. The maximum target charging efficiency calculation unit B109 calculates the ignition retard amount from the difference between the basic ignition timing calculated by a first target ignition timing calculation unit B114 (described later) of the engine control unit 16 and the first target ignition timing. At the same time, the maximum target charging efficiency is calculated using this ignition retard amount. A method for calculating the maximum target charging efficiency will be described later. In the second target charging efficiency calculation unit B110, the first target charging efficiency calculated by the first target charging efficiency calculation unit B108 and the maximum target charging efficiency calculated by the maximum target charging efficiency calculation unit B109 The second target filling efficiency limited to the maximum target filling efficiency is calculated by selecting the minimum value between the two. Note that engine stall can be prevented by prohibiting the restriction based on the maximum target charging efficiency when the engine is started or during idling.

  In the engine control unit 16, the target throttle opening calculation unit B112 calculates the second target charging efficiency calculated by the second target charging efficiency calculation unit B110 of the torque I / F unit 15 and the engine speed (idle). The target intake air amount is calculated from the target engine speed), and the target throttle opening that can achieve the target intake air amount with high accuracy is calculated, and the electronically controlled throttle valve 2 is actually driven. As a result, based on the detection result of the airflow sensor 4 or the intake manifold pressure sensor 6, the actual charging efficiency calculation unit B113 calculates the actual charging efficiency by simulating the charging delay of the surge tank 5 by primary filter processing or the like. The Using this actual charging efficiency, the basic target ignition timing is calculated by the first target ignition timing calculation unit B114, correction based on the engine water temperature and intake air temperature, retard correction when the catalyst is activated early, and / or Alternatively, after correction such as retard correction by knock control, the first target ignition timing is calculated. Thereafter, the calculated first target ignition timing torque is input again to the first actual output torque calculation unit B106 of the I / F unit 15, and the above calculation is repeatedly executed. With such a configuration, the first target output torque and the first actual output torque can coincide with each other during steady operation.

  When the second target output torque calculation unit B105 of the torque control unit 14 receives a torque request from the vehicle side and calculates the second target output torque, the second target ignition timing calculation unit B111 The target ignition timing is calculated. This second target ignition timing calculation method will be described later. In the final target ignition timing calculation unit B115 of the engine control unit 16, the first target ignition timing calculated by the first target ignition timing calculation unit B114 and the second target ignition timing calculation unit B111 calculated by the second target ignition timing calculation unit B111. Among the target ignition timings, when the second target output torque is smaller than the first target output torque and it is determined that the operating state can be retarded, or conversely, when the second target output torque is larger and the operating state is advanceable If it is determined, the second target ignition timing is selected, otherwise the first target ignition timing is selected and determined as the final target ignition timing. The ignition retard amount calculated by the maximum target charging efficiency calculation unit B109 is the basic ignition timing calculated by the first target ignition timing calculation unit B114 and the final target calculated by the final target ignition timing calculation unit B115. It may be calculated from the difference from the ignition timing.

  In the second actual output torque calculation unit B116 of the torque I / F unit 15, the second target ignition timing calculated by the second target ignition timing calculation unit B111 and the actual charging calculated by the actual charging efficiency calculation unit B113. From the efficiency, the second actual output torque is calculated. The second actual output torque calculation method of the second actual output torque calculation unit B116 is the same as the first actual output torque calculation method of the first actual output torque calculation unit B106. In the subsequent first target output torque correction calculation unit B117, the first target output torque correction amount is calculated. This is because when the second actual output torque calculated at the time when the second target output torque is calculated is larger than the second target output torque, it is determined that the second target output torque cannot be achieved only by the ignition retard. This is a correction for achieving the second target output torque by controlling the intake air amount by correcting the first target output torque, and the difference between the second actual output torque and the second target output torque. On the other hand, the first target output torque correction amount is calculated by adding a predetermined amount or multiplying by a predetermined coefficient, and the first target output torque correction amount is a first target output torque calculation unit. Reflected in B104. This first target output torque correction amount is maintained during ignition retard due to the second target output torque. Note that the intake air amount control is performed according to the first target output torque even during the retard control by the second target output torque. With such a configuration, the second target output torque and the second actual output torque can coincide with each other. The third actual output torque calculation unit B118 calculates a third actual output torque corresponding to the torque actually output by the engine, and calculates the vehicle required torque based on the calculated third actual output torque. The third actual output torque calculation method of the third actual output torque calculation unit B118 is the same as the first actual output torque calculation method of the first actual output torque calculation unit B106.

  Next, the actual output torque calculation of the first actual output torque calculation unit B106 (and the second actual output torque calculation unit B116 and the third actual output torque calculation unit B118) will be described with reference to FIGS. The second target ignition timing calculation of the second target ignition timing calculation unit B111 will be described in detail. FIG. 6 is a conceptual diagram showing the relationship between actual output torque and ignition timing, and FIG. 7 is a diagram showing an embodiment of actual output torque calculation.

  FIG. 6 shows that the output torque (the indicated mean effective pressure) y is an ignition timing x and a quadratic function with the advance side taken positive with respect to the top dead center TDC under an operating condition of a certain engine speed and charging efficiency. An approximate case is shown, and these relationships are expressed by the following equation (1).

  Here, since this quadratic function is always convex upward, a takes a negative value. By giving a, b, and c as a map, it is possible to calculate the output torque according to the ignition timing. By the way, if the output torque (basic output torque) ya when the ignition timing is operated at the basic ignition timing map value xa is mapped, c can be calculated by the following equation (2). There is no need to

  Based on the above, an embodiment of the actual output torque calculation (first actual output torque calculation unit B106) shown in FIG. 7 will be described. As shown in FIG. 7, the first actual output torque calculator B106 includes a basic output torque calculator B201, a coefficient a calculator B202, a coefficient b calculator B203, a coefficient c calculator B204, and an actual output. A torque calculation unit B205 is provided.

  The basic output torque calculation unit B201 calculates the basic output torque ya based on the actual charging efficiency calculated by the actual charging efficiency calculation unit B113 and the separately calculated engine speed (target engine speed during idling). The Similarly, the coefficients a and b are calculated in the coefficient a calculation unit B202 and the coefficient b calculation unit B203. Subsequently, in the coefficient c calculation unit B204, from the basic ignition timing xa calculated by the first target ignition timing calculation unit B114 and the basic output torque ya calculated by the basic output torque calculation unit B201, according to the equation (2). The coefficient c is calculated. In the actual output torque calculation unit B205, the actual output torque y1 is calculated by the equation (1) from the coefficients a, b, c calculated so far and the first target ignition timing x1 that is the actual ignition timing. .

  When the second actual output torque is calculated by the second actual output torque calculator B116, the same is calculated from the coefficients a, b, c and the second target ignition timing x2 by the actual output torque calculator B205. When the second actual output torque y2 is calculated by the equation (1) and the third actual output torque is calculated by the third actual output torque calculating unit B118, the coefficient is calculated by the actual output torque calculating unit B205. Similarly, the third actual output torque yf is calculated from equation (1) from a, b, c and the final target ignition timing xf.

FIG. 8 is a diagram illustrating an embodiment of the second target ignition timing calculation. In FIG. 6, the target ignition timing x _t when the target output torque yt is given can be obtained by solving the equation (1) for the ignition timing x as shown in the following equation (3).

Since the quadratic function is convex upward and the target ignition timing is always only retarded from the MBT, a value on the + side of ± is used, and the target ignition timing _xt is _expressed by the following equation (4). It is represented by

  Based on the concept of the second target ignition timing calculation described above, an embodiment of the second target ignition timing calculation by the second target ignition timing calculation unit B111 shown in FIG. 8 will be described. As shown in FIG. 8, the second target ignition timing calculation unit B111 is provided with a second target ignition timing calculation unit B206 and a retard limit calculation unit B207.

In the second target ignition timing calculation unit B206, the coefficients a, b, and c calculated in the first actual output torque calculation unit B106 and the second target calculated in the second target output torque calculation unit. From the output torque _yt2 , the second target ignition timing _xt2 is calculated using Expression (4). In subsequent retard limit calculating unit B 207, the second target ignition timing x _t2 by comparing the retard limit of the ignition timing which is separately computed is limited by the retard limit. That is, when the following values of the second predetermined retard limit target ignition timing x _t2 is preset is outputted as a value from the retard limit calculating unit B 207, when large reverse, the value of the retard limit output Is done. With such a configuration, the actual output torque calculation and the second target ignition timing calculation can be realized. With the configuration described above, the driver request output that is torque-controlled by the intake air amount and the vehicle-side torque request that is torque-controlled by the ignition timing can be realized with a simple logic configuration.

  Next, the maximum target charging efficiency calculation by the maximum target charging efficiency calculation unit B109 will be described in detail with reference to FIG. FIG. 9 is a diagram showing an embodiment of maximum target charging efficiency calculation. As shown in FIG. 9, the maximum target charging efficiency calculation unit B109 is provided with an ignition retard amount calculation unit B208, a maximum target charging efficiency calculation unit B209, and a filter processing unit B210.

  In the ignition retard amount calculation unit B208, the ignition retard amount Δx is calculated from the difference between the basic ignition timing xa calculated by the first target ignition timing calculation unit B114 and the first target ignition timing x1. In the maximum target charging efficiency calculation unit B209, the maximum target charging efficiency z is calculated based on the ignition retard amount Δx calculated by the ignition retard amount calculation unit B208 and the engine speed Ne calculated separately. Here, the maximum target charging efficiency z is determined using a map prepared in advance with the ignition retard amount Δx and the engine speed Ne as axes. With such a configuration, the maximum target charging efficiency z can be calculated with high accuracy. Subsequently, the filter processing unit B210 performs a filter process for smoothing on the maximum target filling efficiency z by the following equation (5). Note that the filter constant K used for the filter processing is switched between when the maximum target charging efficiency z changes to the increasing side and when the maximum target charging efficiency z changes to the decreasing side, so that the responsiveness of the target charging efficiency when returning from the ignition retarded state In addition, it is possible to simultaneously suppress a rapid change in the target charging efficiency during ignition retard.

  By comparing the maximum target charging efficiency z after this filter with the first target charging efficiency calculated by the first target charging efficiency calculation unit B108, the second target charging efficiency calculation unit B110 The target filling efficiency is calculated.

  In the maximum target charging efficiency calculation unit B109, the maximum target charging efficiency may be calculated by approximating the maximum target charging efficiency using a plurality of tables around the engine speed. The maximum target charging efficiency calculation of the maximum target charging efficiency calculation unit B109 in this case will be described in detail with reference to FIGS. FIG. 10 is a conceptual diagram showing the relationship between the ignition retard amount and the maximum target charging efficiency, and FIG. 11 shows an embodiment when the relationship between the ignition retard amount and the maximum target charging efficiency is approximated using a predetermined arithmetic expression. FIG. In FIG. 11, B211 is a coefficient k1 calculation unit, B212 is a coefficient k2 calculation unit, and B213 is a maximum target filling efficiency calculation unit. B208 and B210 are the same as those in FIG.

  FIG. 10 shows a case where the maximum target charging efficiency z is approximated to a square correlation with the ignition retard amount Δx based on the basic ignition timing under an operating condition of a certain engine speed. It is represented by (6).

  Here, since this quadratic function is always convex upward, the coefficient k1 takes a negative value. A coefficient k2 that is a reference maximum target charging efficiency with an ignition retard amount of 0 and a coefficient k1 that corrects the maximum target charging efficiency according to the ignition retard amount are set using a table with the engine speed as an axis. This makes it possible to calculate the maximum target charging efficiency according to the ignition retard amount. Incidentally, even on the advance side from the basic ignition timing, it can be dealt with by approximating the relationship between the ignition retard amount and the maximum target charging efficiency by using a polynomial that appropriately represents the relationship. Based on this relationship, an embodiment of the maximum target charging efficiency calculation (maximum target charging efficiency calculation unit B109) shown in FIG. 11 will be described.

  The coefficient k1 calculation unit B211 calculates the coefficient k1 based on the engine speed Ne. Similarly, the coefficient k2 calculating unit B212 calculates the coefficient k2 based on the engine speed Ne. Subsequently, in the maximum target charging efficiency calculation unit B213, an equation is obtained from the ignition retard amount Δx calculated by the ignition retard amount calculation unit B208 and k1 and k2 calculated by the coefficient k1 calculation unit B211 and the coefficient k2 calculation unit B12. The maximum target filling efficiency is calculated according to (6). Using this maximum target filling efficiency, filter processing for smoothing is performed in the filter processing unit B210, and the maximum target filling efficiency after filtering is calculated. The method of calculating the maximum target charging efficiency using this predetermined calculation formula uses only two tables with the engine speed as the axis, and therefore can be calculated with a small amount of ROM usage. With the above configuration, the target charging efficiency is limited to an appropriate maximum target charging efficiency based on the operating state of the internal combustion engine, and it is possible to effectively avoid deterioration of fuel consumption and control performance.

  The description so far does not describe application to engines with EGR, VVT (variable valve timing), lean burn, and VVL (variable valve lift) that are expected to become popular in the future. The following describes how to apply to engines with these mechanisms and controls. The influence of these changes changes the relationship between the actual output torque and the ignition timing in FIG. 6 and the relationship between the maximum target charging efficiency and the ignition timing in FIG. Here, as an example, a case where VVT is corrected for the maximum target charging efficiency of the maximum target charging efficiency calculation unit B209 will be described. However, correction of the coefficients k1 and k2 of the coefficient k1 calculation unit B211 and the coefficient k2 calculation unit B212, The correction for the basic output torque and the coefficients a and b of the basic output torque calculation unit B201 and the to-block B203, and the correction by EGR or air-fuel ratio may be performed in exactly the same manner.

  FIG. 12 is a diagram showing an embodiment in which VVT is corrected for the maximum target charging efficiency of the maximum target charging efficiency calculation unit B209. The maximum target charging efficiency calculation unit B209 is provided with a maximum target charging efficiency calculation unit B301, a VVT correction coefficient calculation unit B302, and a VVT correction unit B303.

  The maximum target charging efficiency calculation unit B301 calculates the maximum target charging efficiency (reference) from the ignition retard amount Δx and the engine speed Ne. The maximum target filling efficiency (reference) means, for example, the maximum target filling efficiency when the VVT phase angle is fixed at the reference position. Next, the VVT correction coefficient calculation unit B302 calculates a VVT correction coefficient from the ignition retard amount Δx and the engine speed Ne. The VVT correction coefficient is a ratio or difference between the maximum target charging efficiency and the maximum target charging efficiency (reference) when the VVT phase angle reaches a predetermined phase angle, and this is stored in the map.

  The VVT correction unit B303 performs VVT correction on the maximum target charging efficiency (reference) calculated by the maximum target charging efficiency calculation unit B301 using the VVT correction coefficient calculated by the VVT correction coefficient calculation unit B302. Here, if the VVT phase angle is the reference position, the VVT correction is not performed. If each VVT phase is a predetermined phase angle, the VVT correction is performed by multiplying or adding the VVT correction coefficient. At this time, the reflection amount of the VVT correction coefficient may be corrected based on the ratio between the target VVT phase angle and the actual VVT phase angle. With the above configuration, it can be easily applied to engines with EGR, VVT (variable valve timing), lean burn, and VVL (variable valve lift) that are expected to become more popular in the future. Can be realized with a simple logic configuration.

  As described above, the actual output torque calculation unit and the maximum target charging efficiency calculation unit are based on at least one of the EGR valve opening degree, the EGR rate, the valve timing, the valve lift amount, and the air-fuel ratio, and Each target charging efficiency is corrected.

  As described above, in the first embodiment, the maximum target charging efficiency is set based on the operating state of the internal combustion engine such as the engine speed and the ignition retard amount, and the target intake air amount is calculated from the target output torque. Then, when determining the target charging efficiency for realizing the target output torque, the limit processing is performed using this maximum target charging efficiency, so that the injector is not driven unnecessarily, and Further, since the throttle opening does not continue to open excessively, the responsiveness is good, and it is possible to obtain an excellent effect that the deterioration of fuel consumption and the deterioration of control performance can be effectively avoided.

1 is a configuration diagram schematically showing an engine according to an embodiment of the present invention. FIG. It is a block diagram which shows the control apparatus of the engine by embodiment of this invention. It is a block diagram which shows the outline | summary of the torque base control by embodiment of this invention. It is a block diagram which shows the torque control part by embodiment of this invention. It is a block diagram which shows the torque I / F part and engine control part by embodiment of this invention. It is a figure which shows the relationship between the output torque and ignition timing by Embodiment 1 of this invention. It is a block diagram which shows the actual output torque calculation means by Embodiment 1 of this invention. It is a block diagram which shows the target ignition timing calculation means by Embodiment 1 of this invention. It is a block diagram which calculates the maximum target filling efficiency by Embodiment 1 of this invention. It is a figure which shows the relationship between the maximum target charging efficiency and ignition retard amount by Embodiment 1 of this invention. It is a block diagram which calculates the maximum target filling efficiency by Embodiment 1 of this invention. It is a block diagram which shows the VVT correction | amendment means by Embodiment 1 of this invention. It is a figure which shows the relationship between the charging efficiency and output torque for demonstrating the subject of a prior art.

Explanation of symbols

  1 engine, 2 electronically controlled throttle valve, 3 throttle opening sensor, 4 airflow sensor, 5 surge tank, 6 intake manifold pressure sensor, 7 EGR valve, 8 injector, 9 ignition coil, 10 ignition plug, 11 crank angle sensor, 12 Accelerator opening sensor, 13 Electronic control unit (ECU), 14 Torque control unit, 15 Torque I / F unit, 16 Engine control unit.

Claims (7)

Throttle opening control means for performing variable control of the intake air flow rate by changing the opening area of the intake passage by controlling the opening of the throttle provided in the intake passage of the internal combustion engine;
Driver request output calculation means for calculating a driver request output for the vehicle based on the operating state of the internal combustion engine and / or the traveling speed of the vehicle and the accelerator operation state of the driver;
A target output torque calculating means for calculating a target output torque or a target average effective pressure to be generated by the internal combustion engine based on the driver request output;
The basic target ignition timing is calculated based on the operating state of the internal combustion engine, the calculated basic target ignition timing is corrected by the engine temperature and intake air temperature of the internal combustion engine, and the retard for activating the catalyst at an early stage. Target ignition timing calculating means for calculating a target ignition timing that has been corrected and / or retarded by knock control;
An actual output torque calculating means for calculating an actual output torque or an actual average effective pressure of the internal combustion engine based on at least the engine speed, the actual charging efficiency, and the target ignition timing;
A target charging efficiency calculating means for calculating a target charging efficiency based on the actual charging efficiency, the actual output torque or the actual average effective pressure, and the target output torque or the target average effective pressure;
A maximum target charging for calculating a maximum target charging efficiency for limiting the target charging efficiency based on at least the engine speed and an ignition retard amount that is a difference between the target ignition timing and the basic target ignition timing; Efficiency calculation means;
The target filling efficiency calculated by the target filling efficiency calculating means is compared with the maximum target filling efficiency calculated by the maximum target filling efficiency calculating means, and the smaller value is selected and the target filling efficiency subjected to the restriction process is selected. Limiting means to output as
A target intake air that calculates a target cylinder air amount that is to be taken in by the internal combustion engine from the target cylinder air amount is calculated based on the target charging efficiency that has been subjected to the limitation process that is output from the limiting unit. A quantity calculating means;
Control means for controlling the throttle opening degree control means so as to control the throttle opening degree so as to realize the target intake air quantity calculated by the target intake air amount calculation means. Engine control device.   2. The control device for an internal combustion engine according to claim 1, wherein the maximum target charging efficiency is set by a map with the engine speed and the ignition retard amount as axes.   The maximum target charging efficiency is set by a table with the engine speed as an axis, is corrected using a predetermined arithmetic expression, and the ignition retard amount is set as a variable in the predetermined arithmetic expression. The control device for an internal combustion engine according to claim 1.   The internal combustion engine according to any one of claims 1 to 3, wherein the maximum target charging efficiency is smoothed by filtering, and the filter constant is switched between when the maximum target charging efficiency is increased and when the maximum target charging efficiency is decreased. Control device.   The actual output torque calculating means and the maximum target charging efficiency calculating means are configured to determine the actual output torque and the maximum target charging based on at least one of EGR valve opening, EGR rate, valve timing, valve lift, and air-fuel ratio. The control device for an internal combustion engine according to any one of claims 1 to 4, wherein the efficiency is corrected respectively.   The control device for an internal combustion engine according to any one of claims 1 to 5, wherein the restriction process by the restriction means is canceled during start-up or idle operation. The target filling efficiency calculating means includes
A filling efficiency-torque conversion coefficient, which is a ratio between the actual filling efficiency and the actual output torque or the actual average effective pressure, is calculated, and the target filling is performed based on the target output torque or the target average effective pressure and the filling efficiency-torque conversion coefficient. To calculate efficiency,
7. The engine according to claim 1, wherein a predetermined value set in advance as the charging efficiency-torque conversion coefficient is used instead of calculating the charging efficiency-torque conversion coefficient at the time of starting. The internal combustion engine control device described.

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