JP2008128082A - Engine torque control device and adjustment method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide engine torque control device and an adjustment method thereof enabling more suitable torque control by setting more suitable reserve torque in torque reserve control. <P>SOLUTION: Actual torque is comprehensively controlled to target torque by compensating shortage due to reserve torque by the suction air quantity to maintain or establishing a condition where a margin is given in advancement side of ignition timing by a predetermined torque margin (reserve torque). Such an engine torque control device (engine control ECU) is provided with a program (an acceleration limit acquiring part B21) acquiring the maximum acceleration (the maximum acceleration limit ΔNE) of engine speed which is achievable in a unit time, a program (an acceleration torque acquiring part B22) determining the torque (acceleration torque) required for acceleration of the maximum acceleration limit ΔNE, and a program (a reserve torque acquiring part B23) variably setting the reserve torque based on the acceleration torque. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the present invention, a torque parameter with low responsiveness such as intake air amount and a torque parameter with high responsiveness such as ignition timing are controlled in a coordinated manner so that the torque parameter having a high responsiveness is set to a torque increasing side. The present invention relates to an engine torque control apparatus that performs so-called torque reserve control in which an actual torque is controlled to a target torque with a margin of a torque margin (reserved torque), and an adjustment method thereof.

  In general, automobiles and the like are equipped with various devices driven by engine output, such as a power steering pump, an alternator, an air conditioner compressor, and the like. These in-vehicle devices may be driven even during idling operation in which engine torque is reduced. For this reason, when these in-vehicle devices are driven, the engine load increases, and the magnitude of the engine torque varies (changes toward the decrease side) as the load varies.

  Here, the torque fluctuation accompanying the load fluctuation can be compensated by controlling the intake air amount (intake amount), for example. However, when the intake air amount is controlled, there is a response delay until a change in the throttle valve opening or the ISC valve (intake throttle valve for idle rotation speed control) opening appears as a change in the in-cylinder charged air amount. For this reason, in the control of the intake air amount, it is not possible to compensate for torque fluctuations (and hence fluctuations in engine rotation speed) caused by load fluctuations of the in-vehicle device with high response. Thus, conventionally, for example, a device described in Patent Document 1 has been proposed as a device for compensating for such torque fluctuation with high responsiveness. Hereinafter, this apparatus will be further described.

This device pays attention to the fact that the change in ignition timing (change to the retard side or advance side) acts on the engine torque with high responsiveness. Thus, compensation is made with high responsiveness. However, in general ignition timing control, in order to satisfy the target torque, the optimal ignition timing (MBT: Minimum advance for the Best Torque), that is, the ignition timing at which both the torque and the fuel consumption rate are best, The timing is controlled. Therefore, depending on the driving situation, the ignition timing may be too close to MBT, and a sufficient margin (torque margin) may not be ensured on the advance side (torque increase side). In such a case, even if the ignition timing is controlled to MBT (maximum torque point), there is a concern that a torque sufficient to compensate for the torque drop due to the driving of the on-vehicle device cannot be obtained. become. Therefore, in the device described in Patent Document 1, the intake amount having low response to torque change and the ignition timing having high response are controlled in a coordinated manner from a predetermined fixed value or a variable value based on the engine operating state. A predetermined torque margin (reserve torque) is provided on the advance side of the ignition timing, and the shortage due to the reserve torque is compensated by controlling the intake air amount. That is, under the torque control by these torque parameters, a sufficient reserve torque is ensured by the ignition timing, and the torque decrease from the MBT due to the reserve torque is canceled by the intake amount. Thus, overall, the actual torque (actual torque) is controlled to the target torque (control target value). Therefore, in this apparatus, the reserve torque can be appropriately released by controlling the ignition timing to the advance side according to the engine load or the like while satisfying the target torque. As a result, it is possible to compensate for torque fluctuations due to driving of the in-vehicle device with high responsiveness.
JP 2006-138300 A

  By the way, in the engine torque control device that performs such torque reserve control, the magnitude of the reserve torque is important. This is because if the reserve torque is set too large, problems such as deterioration of fuel consumption and an increase in exhaust temperature may occur due to the ignition timing being delayed too much. However, in the apparatus described in Patent Document 1, the reserve torque is set as a fixed value or a variable value based on the engine operating state, and the magnitude of the reserve torque does not necessarily reflect individual engine characteristics. It is not a thing. In other words, there is still room for improvement in this respect even in the apparatus described in Patent Document 1.

  The present invention has been made in view of such circumstances, and an engine torque control device and a method of adjusting the engine torque control device that enable more suitable torque control by setting a reserve torque having a more appropriate magnitude in torque reserve control. The main purpose is to provide it.

  Hereinafter, means for solving the above-described problems and the effects thereof will be described.

  In the first aspect of the present invention, the engine torque can be adjusted with a higher responsiveness than the first torque parameter related to the magnitude of the torque (output torque) of the engine to be controlled, and when the first torque parameter is changed. In order to maintain or form a state in which the second torque parameter that acts has a predetermined torque margin on the torque increase side of the second torque parameter, the shortage due to the torque margin is reduced to the first torque parameter. In the engine torque control apparatus that comprehensively controls the actual torque of the engine output to the target torque by compensating with the torque parameter, the torque is based on the maximum acceleration limit amount that is the maximum acceleration amount of the engine speed that can be accelerated per unit time. A torque margin variable means for variably setting the margin is provided.

  The inventor reflects various engine characteristics in the magnitude of the reserve torque in order to develop a device that can suppress the set value of the predetermined torque margin (reserve torque) to the minimum necessary magnitude as much as possible. It was investigated. A more preferable engine operation can be obtained by reflecting the maximum acceleration limit amount (maximum acceleration amount of the engine rotation speed that can be accelerated per unit time), which is one of the engine characteristics, in the reserve torque. As a result, the above-described configuration was invented. Specifically, in the engine, with respect to the fluctuation amount of the rotational speed of the output shaft (engine rotational speed), the performance acceleration limit of the engine itself and the limit (upper limit value) by an arbitrary regulation set by the user or automatically. And the maximum acceleration amount (maximum acceleration limit amount) that can be accelerated per unit time is determined. The reserve torque is usually used for controlling the engine speed. The inventor pays attention to these points, and with the above configuration, the reserve torque is variably set based on the maximum acceleration limit amount, so that the reserve torque is set to an appropriate magnitude, that is, a value closer to the necessary minimum magnitude. Made it possible. That is, according to the device of the first aspect, a reserve torque having a more appropriate magnitude is set in the torque reserve control, and thus more suitable torque control is possible.

  Here, the torque margin variable means can variably set the reserve torque based on a complex function having the maximum acceleration limit amount as a variable. However, in order to simplify the control, this torque margin variable means is basically configured such that the reserve torque becomes larger as the maximum acceleration limit amount becomes larger, and the reserve torque becomes smaller as the maximum acceleration limit amount becomes smaller. It is effective to set it.

  Further, the configuration according to claim 1 is applied to a configuration in which the maximum acceleration limit amount is positively set by the user or automatically (the fluctuation amount of the engine speed is positively regulated). It is particularly effective. In such a case, the maximum acceleration limit amount is usually set to a value suitable for the application (purpose). Therefore, if the above configuration is adopted in such a case, the reserve torque is set to a magnitude suitable for the application (purpose).

  Further, as the unit time of the maximum acceleration limit amount, it is effective to use, for example, a combustion interval (for example, “180 ° CA” for a four-cylinder four-stroke engine).

  According to a second aspect of the present invention, in the apparatus according to the first aspect, the torque margin variable means obtains an acceleration torque that is a torque required for accelerating by the maximum acceleration limit amount. And a torque margin setting unit that variably sets the torque margin based on the acceleration torque acquired by the acceleration torque acquisition unit.

  When the reserve torque is variably set based on the maximum acceleration limit amount, a reserve torque corresponding to the maximum acceleration limit amount can be set, for example, by creating a map (adaptation map) that associates the two in advance through experiments or the like. it can. However, when such a conformity map is created, optimum data (optimum reserve torque) must be acquired for various engine operating conditions, which takes enormous effort and time. For this reason, when considering reduction of work time and cost reduction, a system that enables control with a smaller number of maps is preferable. In this regard, the device according to claim 2 includes an acceleration torque acquisition unit that converts the maximum acceleration limit amount (engine acceleration) into torque. For this reason, it becomes possible to obtain the reserve torque corresponding to the maximum acceleration limit amount without requiring a matching map (or using a simple map or mathematical expression).

  Specifically, for example, as in the invention described in claim 3, the acceleration torque acquisition unit is configured based on the maximum acceleration limit amount and the magnitude of the inertial force generated in the output rotation shaft of the engine. A configuration in which the acceleration torque is obtained is effective. With this configuration, the acceleration torque can be obtained easily and accurately.

  Further, in the apparatus according to claim 3, when the maximum acceleration limit amount is ΔNE and the rotational inertia moment generated on the output rotation shaft of the engine is I, as in the invention according to claim 4. In addition, for the acceleration torque acquisition unit, a configuration in which the acceleration torque is calculated based on the energy value represented by the relational expression “I × ΔNE” is effective. In this way, for example, by using a rotational moment (rotational inertia moment) determined by the engine design value or the like, the maximum acceleration is not required (or a simple map or mathematical expression) for creating a conforming map that requires enormous labor. The limit amount can be converted (converted) easily and accurately into an energy value (corresponding to acceleration torque).

  In order to simplify the control in the device according to any one of claims 2 to 4, as the torque margin setting unit, for example, the value of the acceleration torque itself is set as the reserve torque, or It is effective to adopt a value corresponding to the acceleration torque, for example, a value obtained by calculating (adding, subtracting, multiplying, or dividing) a predetermined coefficient for the acceleration torque as the reserve torque.

  According to a fifth aspect of the present invention, in the apparatus according to any one of the first to fourth aspects, the engine is a part that performs combustion, an intake passage that circulates intake air to the cylinder, and An intake valve for communicating or blocking between the cylinder and the intake passage based on a valve opening / closing operation, and an intake air amount to the cylinder is determined based on an opening of an intake throttle valve provided in the middle of the intake passage. In the case where fuel that is controlled and combusted together with the intake air is supplied to the intake passage, the intake throttling is performed at a target opening calculation timing that is a predetermined timing for the engine. A target opening calculation means for calculating a target opening of the valve, and a time calculated at the target opening calculation timing after a predetermined delay time has elapsed from the target opening calculation timing; Intake throttle valve control means for controlling the opening degree of the intake throttle valve based on the target opening degree, and target fuel which is a timing for calculating the fuel supply amount to the intake passage before the closing timing of the intake valve Intake air amount predicting means for predicting the intake air amount at the closing timing of the intake valve at the supply amount calculation timing, and fuel supply to the intake passage based on the intake air amount predicted by the intake air amount predicting means The longer the at least one of the means for calculating the target value of the amount, the time from the target fuel supply amount calculation timing to the closing timing of the intake valve, and the delay time related to the opening control of the intake throttle valve becomes longer, Delay control variable means for variably setting the maximum acceleration limit amount to a larger value.

  In an intake passage (for example, intake port) injection engine that injects fuel into an intake passage, in order to accurately predict an intake air amount at a future intake valve closing time at a target injection amount calculation time (target fuel supply amount calculation timing) For example, as described above, it is effective to delay the drive of the intake throttle valve (for example, the throttle valve) by a predetermined delay time with respect to the acquisition (calculation) timing of the target opening. In this way, the intake air amount at the intake valve closing timing can be obtained as a more accurate predicted value, and an appropriate value can be set as the target value of the fuel injection amount. However, in this case, there is a slight concern about deterioration of drivability (drivability) due to a delay in torque generation (and a difference from the required intake air amount) due to a delay in driving the intake throttle valve. The degree of deterioration depends on the time from the target fuel supply amount calculation timing to the closing timing of the intake valve (post-injection intake time) and the delay time related to the opening control of the intake throttle valve (throttle valve delay). The longer the (time), the larger it becomes. In this regard, in the above configuration, the maximum acceleration limit amount is variably set to a larger value as the at least one of the post-injection intake time and the throttle valve delay time becomes longer by the delay control variable means. Even if the deterioration of drivability (driability) is a concern, the deterioration will be repaired early. Moreover, in this case, the reserve torque also increases as the value of the maximum acceleration limit amount increases, so that it becomes possible to generate torque with high responsiveness (and thus compensate for torque fluctuation) by releasing the reserve torque, Good drivability can be obtained due to the high responsiveness.

  In the apparatus according to claim 5, when the delay control variable means adopts one that variably sets the maximum acceleration limit amount to a larger value as the post-injection intake time becomes longer, As in the invention described in claim 6, the delay control variable means is calculated based on multiplication by time from the target fuel supply amount calculation timing to the intake valve closing timing. It is effective to variably set the acceleration limit amount to a larger value. By doing so, the maximum acceleration limit amount can be easily and accurately variably set without requiring an enormous troublesome adaptation map for creation (or by a simple map or mathematical expression).

  According to a seventh aspect of the present invention, in the apparatus according to any one of the first to sixth aspects, the engine body temperature (e.g., the engine temperature detected as a cooling water temperature) or an equivalent value thereof is used. Means is provided for making the maximum acceleration limit variable.

  By providing such means, it becomes possible to set the value of the maximum acceleration limit amount to an appropriate value based on the warm-up state of the engine. For example, the active state of the catalyst provided in the exhaust system can be estimated by checking the main body temperature (engine temperature) of the engine (for example, inactive if the engine temperature is low). For this reason, it is effective to set the maximum acceleration limit amount to a larger value so as to promote warm-up and catalyst activity as the engine temperature is lower.

  Instead of the direct engine temperature, a parameter such as an exhaust temperature discharged from the engine, for example, an equivalent value of the engine temperature that indirectly indicates the engine temperature can be used.

  According to an eighth aspect of the present invention, in the apparatus according to any one of the first to seventh aspects, an operation mode determination unit that determines whether or not the engine is operated in a predetermined operation mode; Torque margin forming means for controlling the first torque parameter to the torque increasing side by the torque margin from the target torque while it is determined by the operation mode determining means that the vehicle is operating in the predetermined operation mode. And.

  As described above, if the reserve torque is set too large, there is a possibility that the ignition timing is excessively retarded. Therefore, it is preferable to perform the torque reserve control only when the control is necessary or suitable for execution of the control. In this regard, with the above configuration, by performing the above-described torque reserve control according to the operation mode of the engine, basically, the control is required (or suitable for execution of the control). Only in the predetermined operation mode (however, other conditions can be set separately), the above-described torque reserve control is performed, and the occurrence of the inconvenience associated with the control is suppressed.

  In this case, as the predetermined operation mode, it is effective to employ an operation mode indicating idling operation as in the invention according to claim 9.

  As described above, the above-described torque reserve control is particularly effective when used to compensate for torque fluctuations when the vehicle-mounted device is driven during idling operation in which engine torque is reduced. For this reason, as an engine torque control device that performs torque reserve control, as described above, a device that executes the control during idling operation is particularly useful.

  According to a tenth aspect of the present invention, in the apparatus according to any one of the first to ninth aspects, the torque margin (reserved torque) is calculated from a reference torque that is a torque peak (maximum point). It is characterized by being determined as an offset amount. With such a configuration, the reserve torque can be set easily and accurately, and thus more suitable torque control can be realized.

  In this case, when the engine is a spark ignition engine and the second torque parameter is an ignition timing of the spark ignition engine, the reference is as in the invention according to claim 11. The torque is an optimum ignition timing (MBT: Minimum advance for the Best Torque) corresponding to the ignition timing at which the largest engine torque is obtained in one fuel cycle, and the offset amount is a retard amount from the optimum ignition timing. It is effective to adopt a configuration of With such a configuration, suitable torque control is possible.

  On the other hand, in the invention according to claim 12, in the device according to any one of claims 1 to 11, the engine is a spark ignition engine, and the first torque parameter is the engine. And the second torque parameter is an ignition timing of the spark ignition type engine. By adopting such a configuration, the above torque reserve control can be easily and accurately realized in a manner similar to the apparatus described in Patent Document 1. As described above, the intake air amount can be controlled by, for example, the throttle valve opening, the ISC valve (intake throttle valve for idle rotation speed control) opening, or the like.

  On the other hand, as an adjustment method of such an engine torque control device, as in the invention according to claim 13, the first torque parameter related to the magnitude of the engine torque to be controlled and the first torque parameter are changed. In order to maintain or form the second torque parameter acting on the engine torque with higher responsiveness than the case where the torque is increased by a predetermined torque margin on the torque increase side of the second torque parameter, An adjustment method for an engine torque control device that comprehensively controls an actual torque of an engine output to a target torque by supplementing a shortage due to a torque margin with the first torque parameter, and is a maximum acceleration that can be accelerated per unit time The torque margin is calculated based on the maximum acceleration limit amount of the engine speed, which is the amount, and the torque margin is calculated as the engine margin. How to set the Ntoruku controller is effective. With such a method, a reserve torque having a more appropriate magnitude is set based on the above-described maximum acceleration limit amount of the engine rotation speed, and thus more suitable torque control is possible.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment embodying an engine torque control device and an adjustment method thereof according to the present invention will be described with reference to the drawings. Note that the apparatus according to the present embodiment is mounted on an engine control system for a reciprocating engine as an engine for a four-wheeled vehicle, for example. This device is also a torque control device that performs so-called torque reserve control, similarly to the device described in Patent Document 1.

  First, a schematic configuration of a vehicle control system in which a torque control device according to this embodiment is mounted will be described with reference to FIG. Note that a multi-cylinder (for example, four-cylinder) engine is assumed as a control target of the present embodiment. However, in FIG. 1, only one cylinder (cylinder) is shown for convenience of explanation.

  As shown in FIG. 1, this engine control system is constructed with an engine 10 (internal combustion engine) as a control target and various sensors for controlling the engine 10, an ECU (electronic control unit) 50, and the like. Has been.

  The engine 10 to be controlled here is a spark ignition type reciprocating engine, and basically includes a cylinder 20 formed by a cylinder block 10a. The cylinder block 10a is provided with a cooling water passage 10b serving as a cooling water passage and a water temperature sensor 10c for detecting the temperature (cooling water temperature) of the cooling water mainly circulating through the engine 10 through the cooling water passage 10b. The engine 10 is cooled by the cooling water. A piston 20a is accommodated in the cylinder 20, and a crankshaft as an output shaft (not shown) is rotated by the reciprocation of the piston 20a. A crank angle sensor 10d that outputs a crank angle signal is provided at predetermined crank angles (for example, at a cycle of 30 ° CA) on the outer peripheral side of the crankshaft, and the rotation angle (engine speed) of the crankshaft is detected. It is possible. A cylinder head is fixed to the upper end surface of the cylinder block 10a, and a combustion chamber 20b is formed between the cylinder head and the upper surface of the piston 20a.

  The cylinder head is formed with an intake port (an intake port through which intake air flows into the cylinder 20) and an exhaust port (an exhaust port through which exhaust from the cylinder 20 flows) open to the combustion chamber 20b. The exhaust port is opened and closed by an intake valve 21 and an exhaust valve 22 that are driven by cams attached to camshafts that interlock with the crankshaft. Further, an intake pipe 30 (intake manifold) for sucking outside air into each cylinder of the engine 10 is connected to the intake port, and combustion gas (exhaust gas) from each cylinder of the engine 10 is discharged to the exhaust port. For this purpose, an exhaust pipe (exhaust manifold) 40 is connected. A surge tank 30a whose passage area is enlarged (expanded) is provided in the middle of the intake pipe 30 to prevent intake pulsation and intake interference, and the intake pipe pressure is detected in the surge tank 30a. An intake pipe pressure sensor 30b is provided. The intake valve 21 and the exhaust valve 22 communicate with each other between the cylinder 20 and the intake port (intake passage) and between the cylinder 20 and the exhaust port (exhaust passage) based on each valve opening / closing operation. Or it is a thing to block.

  The camshaft includes variable valve timing devices 11 and 12 (one of variable valve mechanisms) and cam position sensors 11a and 12a on the intake side and exhaust side, respectively, as valve mechanisms for the intake valve 21 and the exhaust valve 22. Is provided. Here, the variable valve timing devices 11 and 12 continuously control the valve open / close (valve open / close) operation conditions such as the open / close timing and valve overlap amount of the intake / exhaust valves 21 and 22 using a known variable valve timing mechanism (VTC). Is variable. The cam position sensors 11a and 12a are for detecting the rotational position of the camshaft (and thus performing cylinder discrimination and TDC (top dead center) detection). In this system, the sensor outputs of the cam position sensors 11a and 12a are sequentially input to the ECU 50. By operating the variable valve timing devices 11 and 12 appropriately under the command of the ECU 50, the engine operation is sometimes performed. Optimal valve opening / closing operation conditions are realized according to conditions and driver's requirements.

  The intake pipe 30 constituting the intake system of the engine 10 is provided with an air flow meter 32 for detecting the amount of fresh air drawn through the air cleaner 31 at the most upstream part of the intake pipe 30. Further, on the downstream side of the air flow meter 32, an electronically controlled throttle valve 33 (intake throttle valve) whose opening degree is electronically adjusted by an actuator such as a DC motor, and an opening degree of the throttle valve 33 (throttle valve). And a throttle opening sensor 33a for detecting movement (opening fluctuation) and adjusting the amount of air sent to the surge tank 30a provided on the downstream side thereof. It has become.

  Further, the intake pipe 30 is branched so as to introduce air into each cylinder of the engine 10 on the downstream side of the surge tank 30a. An electromagnetic drive type (or piezo drive type) injector 35 (fuel injection valve) that injects and supplies fuel in the vicinity of the intake port of each cylinder is attached to the branch path of the intake pipe 30. Thus, fuel (gasoline) is supplied by injection (port injection) to the intake passage, particularly the intake port of each cylinder.

  In the engine 10, the fuel injected by the injector 35 (strictly speaking, the mixture with intake air) is ignited to burn the fuel. For this reason, the ignition plug 15 provided with the ignition device 15a which consists of an ignition coil etc. is attached to the cylinder head of the engine 10 for every cylinder. That is, when the engine 10 is ignited, the ECU 50 applies a high voltage to the spark plug 15 at a desired ignition timing. Then, by applying this high voltage, a spark discharge is generated between the opposing electrodes of each spark plug 15, and the air-fuel mixture introduced into the combustion chamber 20b is ignited and burned by the generated spark discharge. The engine 10 is a 4-stroke engine. That is, in the engine 10, one combustion cycle by four strokes of intake, compression, combustion, and exhaust is sequentially executed at a “720 ° CA” cycle.

  On the other hand, the exhaust pipe 40 constituting the exhaust system of the engine 10 is provided with a catalyst 41 made of a three-way catalyst for purifying CO, HC, NOx, etc. in the exhaust as an exhaust aftertreatment system for purifying exhaust. An oxygen concentration sensor 41a (for example, a linear detection type A / F sensor or a binary detection type O2 sensor for detecting the air-fuel ratio or rich / lean of the air-fuel mixture targeting exhaust gas is provided upstream of the catalyst 41. Etc.) are provided.

  Although not shown in the figure, in this system as well as the device described in Patent Document 1, various devices driven by the output of the engine 10 such as a power steering pump, an alternator, an air conditioner compressor, etc. Is installed.

  In such a system, the ECU 50 is the part that mainly controls the engine as an electronic control unit. In addition to the various sensors described above, the ECU 50 includes an intake air temperature sensor 50a for detecting the temperature of intake air (intake air temperature), an atmospheric pressure sensor 50b for detecting atmospheric pressure, and an accelerator operation by a driver (driver). Detection signals from various sensors such as an accelerator sensor 50c for detecting the amount are sequentially input. The ECU 50 grasps the operating state of the engine 10 and the user's request based on the detection signals of the various sensors, and operates various actuators such as the injector 35 in accordance with the operation state, so that the optimum according to the situation at the time. In this manner, various controls relating to the engine 10 are performed.

  More specifically, the ECU 50 includes a known microcomputer (not shown). The microcomputer basically includes a CPU (basic processing device) for performing various calculations, a RAM (Random Access Memory) as a main memory for temporarily storing data and calculation results during the calculation, ROM (read-only storage device) as a program memory, EEPROM (electrically rewritable non-volatile memory) as a data storage memory, backup RAM (RAM powered by a backup power source such as an in-vehicle battery), and Consists of various arithmetic devices such as A / D converters and clock generation circuits, input / output ports for inputting / outputting signals to / from the outside, storage devices, signal processing devices, communication devices, etc. Has been. The ROM stores various programs related to engine control including a program related to torque control, a control map, and the like, and the data storage memory (EEPROM) includes various data including engine 10 design data. Each of the control data is stored in advance.

  In general, the amount of air taken into the cylinder (intake air amount) is determined at the closing timing of the intake valve (intake valve closing timing). For this reason, in order to accurately control the air-fuel ratio, and thus the torque generated by combustion in the engine 10, the intake air amount is calculated after the intake valve closing timing, and the fuel injection is performed based on the calculated intake air amount. It is preferable to calculate and set a target value (target injection amount) of the amount. However, in the intake port (intake passage) injection engine 10 mounted in the system, the timing for calculating the target injection amount (target injection amount calculation timing) is earlier than the intake valve closing timing. Therefore, in order to accurately control the air-fuel ratio, torque, etc., the intake air amount (intake amount) at the future intake valve closing timing is accurately predicted at the target injection amount calculation time point (target injection amount calculation timing). Becomes important. Therefore, in the present embodiment, the intake air amount is predicted based on the throttle valve opening until the target injection amount calculation timing. However, since the throttle valve 33 is accompanied by a delay in operation, it is difficult to accurately predict the actual throttle valve opening by following the target value. For this reason, in the present embodiment, by intentionally delaying the operation of the throttle valve 33, the measurement accuracy (prediction accuracy) of the intake air amount is improved while sacrificing responsiveness that does not affect the drivability (operability). The method is adopted. That is, in the engine control system, after a predetermined delay time (throttle valve delay time) has elapsed from the timing (target opening calculation timing) at which the target value (target throttle valve opening) for the opening of the throttle valve 33 is calculated. The throttle valve 33 is driven. Hereinafter, the control of the throttle valve opening will be described with reference to FIG. FIGS. 2A and 2B are timing charts showing changes in the accelerator operation amount and the throttle valve opening, respectively.

  That is, for example, as shown in FIG. 2A, when the accelerator pedal is depressed by the driver at timing t11 and the pedal operation amount (accelerator operation amount) changes (for example, increases), In the apparatus, the target throttle valve opening is sequentially calculated following the change in the accelerator operation amount. In this case, however, the opening degree control of the throttle valve 33 (FIG. 1) based on the respective target values has passed a predetermined delay time (for example, a fixed value of about “50 to 100 msec, throttle valve delay time DT) from the calculation. I will do it later. That is, as indicated by a solid line L12 in FIG. 2B, at the timing t12 when the throttle valve delay time DT has elapsed from the target opening calculation timing t11, the target throttle valve opening is set as the control target value. As a result, the throttle valve 33 is driven with respect to the opening. However, at this time, as indicated by a broken line L12a in FIG. 2B, the actual throttle valve opening (actual throttle valve opening) is set to the set control target value (target throttle valve opening). It will change late. This is due to operation delay or control delay of the driving actuator, and can be estimated by approximation using a first-order lag function, for example, as a specific characteristic unique to the throttle valve 33.

  Next, the calculation mode of the target injection amount will be described with reference to FIGS. FIG. 3 is a flowchart showing a basic procedure of the target injection amount calculation process, and FIG. 4 is a diagram showing an outline of a calculation mode of the target injection amount. Also, the values of various parameters used in the processing of FIG. 3 are stored as needed in a storage device such as a RAM, EEPROM, or backup RAM mounted in the ECU 50, and updated as necessary. 3 is basically executed by a program stored in the ROM by the ECU 50, so that each cylinder of the engine 10 has a combustion cycle period, that is, a target injection amount calculation timing t0. It is sequentially executed for each (FIG. 4). FIG. 4 shows the relationship between each timing and period (time) in the series of processing of FIG.

  As shown in FIG. 3, in this series of processes, in step S11, the next intake valve closing timing tc is calculated based on, for example, the engine speed and the crank angle (see also FIG. 4).

  Next, in step S12, for example, the current throttle valve opening detected by the throttle opening sensor 33a and the target throttle valve opening at the time calculated in the period td to t0 (target throttle valve opening acquisition period TAG). The actual throttle valve opening (actual throttle valve opening) at each time point in the period t0 to tc is predicted based on the degree and the operating characteristics of the throttle valve 33. That is, the actual throttle valve opening at the intake valve closing timing tc is also calculated. At this time, the operating characteristic of the throttle valve 33 can be approximated by, for example, a first-order response delay as described above. In addition, in the target throttle valve opening acquisition period TAG, the target throttle valve opening at that time is calculated continuously and sequentially stored in a predetermined storage device (for example, RAM) (details will be described later). . In the period t0 to tc, the opening of the throttle valve 33 is based on each value of the target throttle valve opening at a timing delayed by the throttle valve delay time DT (FIG. 2) from the target value calculation timing. Are controlled.

  In this step S12, the post-injection intake period Tc that is the period from the target injection amount calculation timing t0 that is the processing timing of step S12 to the intake valve closing timing tc that is calculated in step S11 is the throttle valve delay. There is a case where the time is larger than the time DT (Tc> DT). In this case, since the target throttle valve opening is not calculated in the target throttle valve opening acquisition period TAG for the portion exceeding the delay time DT, the above method is used for the portion exceeding the delay time DT. It is necessary to predict the actual throttle valve opening by another method. As the method, for example, prediction is made by linear extrapolation or the like from the timing td ′ after the passage of time DT (= throttle valve delay time) from the target injection amount calculation timing t0 or the actual throttle valve opening predicted value in the vicinity thereof. A method etc. can be adopted.

  In the subsequent step S13, for example, the engine speed at that time detected by the crank angle sensor 10d, the atmospheric pressure detected by the atmospheric pressure sensor 50b, and the actual throttle valve opening at the intake valve closing timing tc (in step S12). And the target value (target valve timing) of the valve timing at the intake valve closing timing tc is obtained for the variable valve timing devices 11 and 12 (FIG. 1). Based on the target valve timing, an actual valve timing (actual valve timing) at the intake valve closing timing tc is predicted.

  The target valve timing (at least one of intake and exhaust timing) is acquired as an appropriate value based on a predetermined map or the like (for example, stored in ROM). Specifically, for example, optimum valve timings (adapted values) are obtained by experiments and the like for each engine speed, each throttle valve opening, and each atmospheric pressure that are assumed in advance, and are written in the map. Thus, the two-dimensional map (which may be a mathematical expression) shows the relationship between the engine operating state and the optimum valve timing.

  Also in the variable valve timing devices 11 and 12, like the throttle valve 33, there is a certain operation delay with respect to the change in the target valve timing. This operation delay can also be approximated by a primary response delay, for example.

  In the subsequent step S14, for example, the engine speed at that time detected by the crank angle sensor 10d, the actual throttle valve opening at the intake valve closing timing tc (calculated in step S12), and the actual valve timing (calculated in step S13). Based on the above, the intake air amount (intake amount) at the intake valve closing timing tc is predicted (calculated).

  In the subsequent step S15, a target injection amount (target value of the fuel injection amount) is calculated based on the predicted intake air amount calculated in the previous step S14. Then, the calculated value is set as the target injection amount of the target cylinder.

  In the present embodiment, the ECU 50 (torque control) is performed during the idling operation while the processes related to the delay control of the throttle valve 33, the prediction of the intake air amount (intake amount), and the target injection amount calculation are performed as described above. Torque reserve control is performed by the device. Hereinafter, the idling control including the torque reserve control will be described in detail with reference to FIGS.

  In executing the idling control, first, it is determined whether or not the execution condition (idling execution condition) is satisfied, that is, whether or not the vehicle is in an idling operation state, and the execution condition is satisfied as shown in FIG. Only in this case, torque reserve control is executed. First, with reference to FIG. 5 and FIG. 6, the execution condition of the idling control, particularly the execution condition of the torque reserve control will be mainly described. 5 and 6 are basically executed at predetermined crank angles or sequentially at predetermined time intervals by executing a program stored in the ROM by the ECU 50.

  As shown in FIG. 5, in this series of processes, first, in step S21, it is determined whether or not a predetermined execution condition related to the idling control is successful. As this execution condition, for example, it is effective to establish that the actual throttle valve opening is fully closed or that the transmission is in a predetermined state (operation position). Then, based on whether or not this condition is met, it is determined whether or not the idling execution condition is met.

  If it is determined in step S21 that the execution condition is satisfied, then in step S211, the idling execution flag is set to “1” (idling execution flag = 1), and then the series of FIG. Terminate the process. On the other hand, if it is determined in step S21 that the execution condition is not satisfied, the idling execution flag is set to “0” (idling execution flag = 0) in the subsequent step S212. The series of processes is terminated.

  On the other hand, in the process of FIG. 6, it is determined whether or not the idling execution condition is satisfied, that is, whether or not the idling execution flag is set to “1” in the first step S31 until the above execution condition is satisfied. When the idling execution flag is set to “1” by the series of processes shown in FIG. 6 and it is determined in this step S31 that the idling execution flag is set to “1”, the process proceeds to the next step S32. It becomes like this.

  In step S32, torque reserve control is executed. More specifically, for example, various processing relating to the torque reserve control is switched from normal control to torque reserve control by setting a flag or the like. The torque reserve control is continuously executed while “1” is set in the idling execution flag.

  Next, this torque reserve control will be described in detail.

  Similar to the device described in Patent Document 1 described above, in this torque reserve control, the actual torque (actual torque (actual torque)) is provided with a predetermined torque margin (reserved torque) on the advance side (torque increasing side) of the ignition timing. The intake air amount (intake air amount) that generates a torque sufficient to compensate for the shortage due to the reserve torque is calculated as the target intake air amount (target value of the intake air amount). become. However, in this embodiment, the reserve torque calculated in the mode shown in FIG. 9 is sequentially set (variably set), and the target intake air amount to which the reserve torque is added is sequentially calculated. Hereinafter, the outline of the target intake air amount calculation process and the details of the reserve torque calculation process will be described with reference to FIGS.

  First, with reference to FIGS. 7 and 8, the calculation mode of the target intake air amount will be described. FIG. 7 is a flowchart showing the processing procedure of the processing, and FIG. 8 is a block diagram showing the part of the ECU 50 relating to the calculation of the target intake air amount, which is divided into functions. 7 is basically executed at predetermined crank angles or sequentially at predetermined time intervals by executing a program stored in the ROM by the ECU 50. The values of various parameters used in the series of processes are stored as needed in a storage device such as a RAM, EEPROM, or backup RAM mounted on the ECU 50, and updated as necessary.

  As shown in FIG. 7, in this series of processing, first, in step S41, based on the engine operating state, a target engine speed (for example, “ About 700 rpm "). Specifically, for example, it is obtained by using a predetermined map or the like in which an appropriate value is written in advance by an experiment or the like (which may be a mathematical expression). For example, the presence or absence of activity of the catalyst 41, the engine temperature (detected as the cooling water temperature by the water temperature sensor 10c), and the like are effective as the engine operating state used here.

  In the subsequent step S42, for example, the target torque is calculated based on the target engine speed, the accelerator operation amount, and the engine operating state acquired in the previous step S41. Specifically, for example, it is obtained by using a predetermined map or the like in which an appropriate value is written in advance by an experiment or the like (which may be a mathematical expression). As the engine operating state used here, for example, engine speed, various losses including internal loss and external loss, and the like are effective. Of these, internal loss corresponds to mechanical friction loss, pumping loss, etc., and external loss corresponds to engine load resulting from driving various on-vehicle devices (for example, the pumps and compressors described above) driven by engine output. To do.

  Next, in step S43, the above-described reserve torque, that is, a predetermined torque margin provided on the advance side of the ignition timing is acquired (details will be described later). In step S44, the target torque correction unit B11 (FIG. 8) performs a predetermined correction calculation (set reserve torque) based on the reserve torque calculated in the previous step S43. Specifically, for example, the target torque is added (increased) by the reserve torque. As a result, the target torque acquired in the previous step S42 is corrected.

  In subsequent step S45, the target intake air amount acquisition unit B12 (FIG. 8) acquires the target intake air amount (target value of the intake air amount) based on the target torque corrected in step S44. Specifically, for example, it is obtained by using a predetermined map or the like in which an appropriate value is written in advance by an experiment or the like (which may be a mathematical expression). The acquired target intake air amount is sequentially stored in a predetermined storage device (for example, RAM). That is, in the present embodiment, the above-described delay control (FIGS. 2 to 4) is executed based on the target intake air amount thus obtained, and the target throttle valve opening is sequentially set for the throttle valve 33 (FIG. 1). Will be.

  Next, the process of step S43 in FIG. 7, that is, the reserve torque calculation process will be described in more detail. In the present embodiment, when calculating the reserve torque, more appropriate torque control can be performed by setting a reserve torque having a more appropriate magnitude through the processing of FIG. Hereinafter, with reference to FIG. 9 and FIG. 10, a processing mode according to step S43 of FIG. 7, that is, a calculation mode of the reserve torque value will be described. Here, FIG. 9 is a flowchart showing the processing procedure of the same processing, and FIG. 10 is a block diagram showing the ECU 50 (torque control device), in particular, the part relating to the calculation of the reserve torque value, which is divided into functions. It is.

  As shown in FIG. 9, in this series of processes, first in step S51, the acceleration limit acquisition unit B21 (FIG. 10) uses the engine temperature (water temperature sensor 10c) in the present embodiment based on a predetermined engine operating state. The maximum acceleration amount (maximum acceleration limit amount) of the engine speed that can be accelerated per unit time is calculated and set on the basis of the detected coolant temperature.

  Here, the maximum acceleration limit amount will be described with reference to FIG. FIG. 11 is a schematic diagram showing an example of the maximum acceleration limit amount.

  As shown in FIG. 11, in the control system of the present embodiment, the maximum acceleration limit amount is positively automatically set, thereby restricting the fluctuation amount of the engine rotation speed. That is, at the timing t21, even if the target value of the engine speed is changed in the mode indicated by the one-dot chain line L21 in the figure, the actual engine speed (actual engine speed) is indicated by the solid line L22 in the figure. As shown, the change in the target value (target engine speed) does not completely follow, but increases by a predetermined amount per unit time. As a result, the actual engine speed reaches the target engine speed at timing t22, which is the timing after a predetermined time has elapsed from timing t21.

  A broken line region L22a in FIG. 11 shows the engine speed increase amount per unit time Δt (for example, “180 ° CA”), that is, the maximum acceleration limit amount ΔNE in this case. The maximum acceleration limit amount ΔNE is set for an arbitrary purpose for each engine specification (use). For example, in an engine for a passenger car, it is set for the purpose of increasing the stability of the engine rotation speed and suppressing the deterioration of drivability (driability). For the setting, for example, it can be set in advance as a predetermined value (fixed value or variable value) by experiments or the like. In the present embodiment, in step S51 of FIG. 9 described above, the setting is made using a predetermined table (one-dimensional map) in which appropriate values are written in advance through experiments or the like. Specifically, as the engine temperature (detected as the cooling water temperature by the water temperature sensor 10c) is lower, a larger value is variably set to the maximum acceleration limit amount ΔNE in order to promote warm-up and catalyst activity.

  Returning to the description of the series of processes shown in FIG.

  As shown in FIG. 9, in step S52 following the previous step S51, the maximum acceleration limit amount ΔNE acquired in the previous step S51 by the acceleration torque acquisition unit B22 (acceleration torque acquisition unit, FIG. 10) and the engine To accelerate by the maximum acceleration limit amount ΔNE based on the inertial force (inertia characteristics) determined based on 10 design values (for example, design data such as flywheel stored in EEPROM) and the engine speed at that time Calculate the required torque (acceleration torque). Specifically, by multiplying the rotational moment of inertia I as the inertial force by the maximum acceleration limit amount ΔNE (I × ΔNE), an energy value necessary for the acceleration (this corresponds to the acceleration torque) is acquired.

  In subsequent step S53, the reserve torque acquisition unit B23 (FIG. 10) estimates (calculates) a post-injection intake period Tc (FIG. 4), which is a period from the target injection amount calculation timing to the next intake valve closing timing, By this post-injection intake period Tc, the maximum acceleration limit amount ΔNE set in the previous step S51 and the acceleration torque acquired in the previous step S52 are corrected. Specifically, a new value is obtained by multiplying the maximum acceleration limit amount ΔNE by the post-injection intake period Tc, that is, by performing an operation such as “ΔNE (after correction) = ΔNE (before correction) × Tc”. Is set (variably set) as the maximum acceleration limit amount ΔNE, and a new acceleration torque (= acceleration torque before correction × Tc) based on the maximum acceleration limit amount ΔNE is acquired. Then, the new acceleration torque is set as the above-described reserve torque magnitude (reserve torque value).

  As described above, in the present embodiment, the target intake air amount is calculated in the manner shown in FIG. More specifically, the reserve torque included in the target intake air amount is calculated in the manner shown in FIG. As will be described below, in this embodiment, the ignition timing is adjusted so that the actual torque (estimated torque) matches the target torque with respect to the intake air amount in which the reserve torque is set (added) in this way. Try to swallow. As a result, the actual torque (actual torque) is controlled to the target torque with a predetermined torque margin (reserved torque) provided on the ignition timing advance side (torque increasing side). That is, in the present embodiment, the target ignition timing (target value of the ignition timing) is not relative to the optimal ignition timing (MBT: Minimum advance for the Best Torque), but is a reserve torque than the MBT (step S44 in FIG. 7). Only the retarding side (torque decreasing side) is set. As described above, the torque shortage due to the reserve torque is compensated by the intake air amount (intake amount).

  Hereinafter, the calculation mode of the target ignition timing will be described with reference to FIGS. 12 and 13. FIG. 12 is a flowchart showing the processing procedure of the same process, and FIG. 13 is a block diagram showing the part of the ECU 50 relating to the calculation of the target ignition timing, divided into functions. In addition, the processing of FIG. 12 is basically performed sequentially for each cylinder of the engine 10 at each combustion cycle period (at each target ignition timing calculation timing) by executing a program stored in the ROM by the ECU 50. Executed. Incidentally, in the present embodiment, as an example, the series of processing in FIG. 12 is executed after step S15 in FIG. Various parameter values used in this series of processing are also stored in a storage device such as a RAM, EEPROM, or backup RAM mounted in the ECU 50 as needed, and updated as needed.

  As shown in FIG. 12, in this series of processing, first, in step S61, the target torque calculated in step S42 of FIG. 7 is acquired. Next, in step S62, the actual engine estimator B31 (FIG. 13) determines the actual engine based on the engine operating state at that time (for example, engine speed, intake air amount, air-fuel ratio, etc. detected by various sensors). Torque (actual torque) is calculated.

  In the subsequent step S63, the torque comparison unit B32 and the ignition delay amount acquisition unit B33 (FIG. 13) compare the target torque acquired in each of these steps with the actual torque, and the actual torque and the target torque are obtained. An ignition retardation amount R that matches is calculated. Specifically, the torque comparison unit B32 obtains a torque efficiency (for example, “target torque / actual torque”) that is a ratio between the target torque and the actual torque. Based on this torque efficiency, the ignition retardation amount acquisition unit B33 calculates an ignition retardation amount R such that the actual torque matches the target torque. Here, the ignition retard amount acquisition unit B33 has a table (one-dimensional map) as shown in FIG. 13, for example. That is, as shown in the graph in FIG. 13, the ignition delay amount R is calculated as a larger value as the torque efficiency is smaller, in other words, as the actual torque is larger than the target torque.

  Based on the ignition retard amount R thus acquired, in the subsequent step S64, the target ignition timing is calculated by the target ignition timing acquisition unit B34 (FIG. 13). Specifically, for example, the MBT is acquired using a predetermined map or the like in which an appropriate value is written in advance through experiments or the like (which may be a mathematical expression), and the timing of the retard side by the ignition retard amount R from the MBT A target ignition timing is calculated. Then, the calculated value is set as the target ignition timing of the target cylinder.

  In the present embodiment, combustion is performed in each cylinder while the above processes are performed. As a result, during the idling operation, the torque reserve control described above is performed, and the reserve torque is appropriately released even if torque fluctuation occurs due to the driving of the vehicle-mounted device described above. As a result, the torque fluctuation can be compensated with high responsiveness. In addition, at this time, a more appropriate torque control can be performed by calculating and setting a reserve torque having a more appropriate magnitude through the processing of FIG.

  As described above, according to the engine torque control device and the adjustment method thereof according to the present embodiment, the following excellent effects can be obtained.

  (1) With respect to the intake air amount to the cylinder 20 and the ignition timing of the engine 10 which is a spark ignition engine, a margin of a predetermined torque margin (reserved torque) is provided on the torque increase side (advance side) of the ignition timing. In order to maintain or form the state, the shortage due to the reserve torque is compensated by the intake air amount, and the actual torque of the engine output is comprehensively controlled to the target torque. In such an engine torque control device (engine control ECU 50), a program for acquiring a maximum acceleration limit amount (see FIG. 11) that is a maximum acceleration amount of the engine speed that can be accelerated per unit time (acceleration limit acquisition shown in FIG. 10). Part B21), a program (acceleration torque acquisition part B22 shown in FIG. 10) for obtaining an acceleration torque which is a torque necessary for accelerating by the maximum acceleration limit amount, and the reserve torque is variable based on the acceleration torque And a program to be set (torque margin setting unit, reserve torque acquisition unit B23 shown in FIG. 10 and step S44 in FIG. 7). As a result, the reserve torque can be set to an appropriate magnitude, that is, a value closer to the necessary minimum magnitude, and thus more suitable torque control can be achieved.

  (2) The maximum acceleration limit amount ΔNE (FIG. 11) is set positively, that is, provided to regulate the fluctuation amount of the engine speed. As a result, the reserve torque is set to a magnitude suitable for the application (purpose), and more suitable torque control becomes possible.

  (3) “180 ° CA” corresponding to the combustion interval is used as the unit time of the maximum acceleration limit amount ΔNE (FIG. 11). This makes it possible to set the reserve torque generated and released as output torque for each combustion more accurately.

  (4) The reserve torque (torque margin) is determined as an offset amount from the reference torque that becomes a torque peak (maximum point). Specifically, the reference torque is set to the ignition timing at which the largest engine torque can be obtained in one fuel cycle, that is, the optimal ignition timing (MBT), and the offset amount is set to the retard amount from the MBT. As a result, the reserve torque can be set easily and accurately, and more suitable torque control can be realized.

  (5) The acceleration limit acquisition unit B21 is based on the maximum acceleration limit amount ΔNE (FIG. 11) and the magnitude of the inertial force (rotational inertia moment I) generated on the output rotation shaft (crankshaft) of the engine 10. The acceleration torque is determined. Specifically, the acceleration torque is calculated based on the energy value represented by the relational expression “I × ΔNE”. By doing so, it is possible to easily and accurately obtain the acceleration torque without requiring an adaptation map that requires enormous labor for creation.

  (6) A program (target opening calculation means, FIG. 7) for calculating the target opening of the throttle valve 33 (intake throttle valve) at the target opening calculation timing td (FIG. 4) for the engine 10, and the target opening A program for controlling the opening of the throttle valve 33 based on the target opening calculated at the target opening calculation timing td after the elapse of the throttle valve delay time DT from the calculation timing td (intake throttle valve control means, see FIG. 2) And a program for predicting the intake air amount at the intake valve closing timing tc (the closing timing of the intake valve 21) at the target injection amount calculating timing t0 (target fuel supply amount calculating timing) (intake air amount predicting means, FIG. 3). Step S14) and a program for calculating a target value of the fuel supply amount to the intake port (intake passage) based on the estimated intake air amount (FIG. 3). Step S15), and a program (delay control variable means, variably setting the maximum acceleration limit amount ΔNE (FIG. 11) to a larger value as the time Tc from the target injection amount calculation timing t0 to the intake valve closing timing tc becomes longer. Step S53) of FIG. 9 is provided. As a result, even when the drivability (driability) deteriorated due to the drive delay of the throttle valve 33 occurs, the deterioration is repaired at an early stage. Moreover, since the reserve torque also increases as the maximum acceleration limit value increases, it becomes possible to generate torque with high responsiveness (and thus compensate for torque fluctuations) by releasing the reserve torque. Good drivability can be obtained due to high responsiveness.

  (7) In step S53 of FIG. 9, based on the multiplication by the time Tc from the target injection amount calculation timing t0 to the intake valve closing timing tc, the maximum acceleration limit amount ΔNE (FIG. 11) is increased as the time Tc becomes longer. Variably set to a large value. By doing so, the maximum acceleration limit amount ΔNE can be variably set easily and accurately without requiring a fitting map that requires enormous labor for creation.

  (8) The program includes a program for changing the maximum acceleration limit amount ΔNE based on the engine body temperature (engine temperature). As a result, the value of the maximum acceleration limit amount ΔNE can be set to an appropriate value based on the warm-up state of the engine 10, and thus warm-up and catalyst activity can be promoted.

  (9) As the reserve torque acquisition unit B23 shown in FIG. 10, the value of the acceleration torque itself is set as the reserve torque (setting itself is performed in step S44 in FIG. 7). Thereby, simplification of control can be achieved.

  (10) A program for determining whether or not the engine 10 is operating in an operation mode indicating idling operation (operation mode determination means, FIG. 5) and while it is determined that the engine 10 is operating in that operation mode The first torque parameter is configured to include a program (torque margin forming means, FIG. 6) that controls the torque on the torque increasing side by the torque margin from the target torque. By doing so, the torque reserve control described above is performed only during the idling operation, and the occurrence of inconvenience associated with the control is suppressed.

  (11) As a torque parameter for controlling the engine torque, a combination of an ignition timing with a fast response speed and an intake air amount with a slow response speed is used. By doing so, the above-described torque reserve control can be easily and accurately realized in a manner similar to the apparatus described in Patent Document 1.

  (12) As an adjustment method of the engine torque control device (ECU 50), the reserve torque is obtained based on the maximum acceleration limit amount ΔNE of the engine rotation speed that is the maximum acceleration amount that can be accelerated per unit time, and the reserve torque is obtained. Minutes are set in the engine torque control device (ECU 50). With such a method, a reserve torque having a more appropriate magnitude is set based on the aforementioned maximum acceleration limit amount ΔNE of the engine rotation speed, and thus more suitable torque control is possible.

  The embodiment described above may be modified as follows.

  When the delay time DT (FIG. 2) relating to the opening degree control of the throttle valve 33 is set as a variable value, for example, the maximum acceleration limit amount ΔNE is variably set to a larger value as the delay time DT becomes longer. It is also effective to have a configuration including a program. Even with such a configuration, an effect similar to the effect of the above (6) can be obtained.

  In the above embodiment, as shown in FIG. 13, the ignition timing is adjusted so that the actual torque (estimated torque) matches the target torque for the intake air amount for which the reserve torque is set (added). . However, the present invention is not limited to this. For example, as shown in FIG. 14 (block diagram corresponding to FIG. 13), a reserve torque adding unit B31a for adding the reserve torque to the target torque is provided instead of the actual torque estimating unit B31. It can also be set as the provided structure. That is, in this case, the reserve torque addition value by the reserve torque addition unit B31a is used instead of the estimation torque by the actual torque estimation unit B31. Even with such a configuration, basically, the above-described torque reserve control can be similarly performed.

  In the above embodiment, the delay control (FIGS. 2 to 4) of the throttle valve 33 is performed. However, it is not essential to execute such delay control, and the opening of the throttle valve 33 may be controlled based on the target throttle valve opening at that time without providing a delay time. That is, in this case, the target injection amount is calculated based on the target throttle valve opening calculated at the target injection amount calculation timing t0 (FIG. 4). Even with such a configuration, basically, the above-described torque reserve control can be similarly performed.

  In the embodiment described above, a configuration is provided that includes a program that makes the maximum acceleration limit amount ΔNE variable based on the engine body temperature (engine temperature). However, instead of the direct engine temperature, the maximum acceleration limit amount ΔNE is made variable based on an equivalent value of the engine temperature that indirectly indicates the level of the engine temperature (for example, the exhaust temperature discharged from the engine 10 or the like). It can also be set as the structure provided with a program. Also in this case, the same effect as the effect (8) or an equivalent effect can be obtained.

  In addition, since the higher the engine speed, the more likely it becomes unstable. For example, the larger the target engine speed acquired in step S41 of FIG. It is also effective to have a configuration that includes a program that performs the above process.

  It is not essential to make this maximum acceleration limit amount ΔNE variable, but it may be a predetermined fixed value (constant), for example. By doing so, the control is simplified and the number of matching maps can be reduced.

  The maximum acceleration limit amount ΔNE is set to an automatically set limit (upper limit value). However, the present invention is not limited to this, and the maximum acceleration limit amount ΔNE may be set by the user. Further, it may not be positively provided, but may be a performance acceleration limit of the engine itself.

  -The control method of the intake air amount (intake amount) is not limited to that based on the throttle valve opening, but is arbitrary. For example, the intake air amount may be controlled by the opening degree of an ISC valve (intake throttle valve for idle rotation speed control) or the like.

  -As a torque parameter for controlling the engine torque, it acts on the engine torque with an arbitrary first torque parameter and higher responsiveness than when the first torque parameter is changed (the torque increases or decreases). As long as it is a combination with the second torque parameter), basically any parameter can be adopted.

  -You may comprise so that torque reserve control may be performed in operation modes other than the operation mode which shows idling operation.

  In short, if the configuration includes a program (torque margin variable means) that variably sets the reserve torque (torque margin) based on the maximum acceleration limit amount ΔNE, the same or similar effect as the effect (1) above The effect is achieved and the intended purpose is achieved.

  As a method of adjusting the engine torque control device (ECU 50), the user himself obtains the reserve torque based on the maximum acceleration limit amount ΔNE and sets the reserve torque amount in the engine torque control device (ECU 50). You may make it do. Even in such a case, the same effect as the effect (12) or an equivalent effect can be obtained.

  -The type and system configuration of the engine to be controlled can be changed as appropriate according to the application.

  In the embodiment and the modification, it is assumed that various kinds of software (programs) are used. However, similar functions may be realized by hardware such as a dedicated circuit.

BRIEF DESCRIPTION OF THE DRAWINGS The configuration diagram which shows the outline of the engine control system to which this apparatus and method were applied about one Embodiment of the engine torque control apparatus which concerns on this invention, and its adjustment method. (A) And (b) is a timing chart which shows the transition about an accelerator operation amount and a throttle valve opening, respectively. The flowchart which shows the basic procedure of target injection amount calculation processing. The figure which shows the outline | summary of the calculation aspect of target injection amount. The flowchart which shows the process sequence of the process which concerns on the execution condition especially about the idling control which concerns on this embodiment. The flowchart which shows the processing content of the idling control. The flowchart which shows the process sequence of target intake air amount calculation. The block diagram which showed the part which concerns on calculation of the target intake air quantity of the engine torque control apparatus (ECU for engine control) which concerns on this embodiment in block form according to the function. The flowchart which shows the process sequence of a reserve torque calculation process. The block diagram which showed the part which concerns on calculation of the reserve torque value of the engine torque control apparatus (ECU for engine control) which concerns on this embodiment especially for each function. The schematic diagram which shows an example of the maximum acceleration limit amount. The flowchart which shows the process sequence of target ignition timing calculation. The block diagram which showed the part which concerns on calculation of the target ignition timing of the engine torque control apparatus (ECU for engine control) which concerns on this embodiment as a block according to function. The block diagram which shows the modification of the calculation aspect of target ignition timing.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine, 15 ... Spark plug, 15a ... Ignition device, 20 ... Cylinder (cylinder), 21 ... Intake valve, 33 ... Throttle valve, 33a ... Throttle opening sensor, 35 ... Injector, 50 ... ECU (electronic control unit) .

Claims (13)

The first torque parameter related to the magnitude of the torque of the engine to be controlled, and the second torque parameter that acts on the engine torque with higher responsiveness than when the first torque parameter is changed, In order to maintain or form a state where a predetermined torque margin is provided on the torque increase side of the torque parameter, the shortage due to the torque margin is supplemented with the first torque parameter to comprehensively calculate the actual torque of the engine output. In the engine torque control device that controls the torque to the target torque,
An engine torque control apparatus comprising: a torque margin variable means for variably setting the torque margin based on a maximum acceleration limit amount that is a maximum acceleration amount of an engine speed that can be accelerated per unit time. The torque margin variable means is:
An acceleration torque acquisition unit for obtaining an acceleration torque which is a torque required for accelerating by the maximum acceleration limit amount;
A torque margin setting unit that variably sets the torque margin based on the acceleration torque acquired by the acceleration torque acquisition unit;
The engine torque control device according to claim 1, comprising:   3. The engine torque control according to claim 2, wherein the acceleration torque acquisition unit is configured to obtain the acceleration torque based on the maximum acceleration limit amount and a magnitude of an inertia force generated in an output rotation shaft of the engine. apparatus. When the maximum acceleration limit amount is ΔNE and the rotational moment of inertia generated on the output rotation shaft of the engine is I,
The engine torque control device according to claim 3, wherein the acceleration torque acquisition unit calculates the acceleration torque based on an energy value represented by a relational expression “I × ΔNE”. The engine includes a cylinder that is a combustion part, an intake passage that circulates intake air to the cylinder, and an intake valve that communicates or blocks between the cylinder and the intake passage based on a valve opening / closing operation, An intake air amount for the cylinder is controlled based on an opening of an intake throttle valve provided in the middle of the intake passage, and fuel to be used for combustion together with the intake air is supplied to the intake passage. And
About the engine, target opening calculation means for calculating a target opening of the intake throttle valve at a target opening calculation timing which is a predetermined timing;
An intake throttle valve control means for controlling the intake throttle valve opening based on the target opening calculated at the target opening calculation timing after a predetermined delay time has elapsed from the target opening calculation timing;
The intake air amount at the closing timing of the intake valve is calculated at a target fuel supply amount calculation timing that is a timing for calculating a target value of the fuel supply amount to the intake passage before the intake valve closing timing. Means for predicting the intake air amount,
Means for calculating a fuel supply amount to the intake passage based on the intake air amount predicted by the intake air amount prediction means;
The maximum acceleration limit amount can be changed to a larger value as at least one of the time from the target fuel supply amount calculation timing to the closing timing of the intake valve and the delay time related to the opening control of the intake throttle valve becomes longer. Variable delay control means to set;
An engine torque control device according to any one of claims 1 to 4.   The delay control variable means variably sets the maximum acceleration limit amount to a larger value as the time becomes longer, based on multiplication by time from the target fuel supply amount calculation timing to the intake valve closing timing. The engine torque control device according to claim 5, wherein   The engine torque control device according to any one of claims 1 to 6, further comprising means for making the maximum acceleration limit amount variable based on a main body temperature of the engine or an equivalent value thereof. Operation mode determination means for determining whether or not the engine is operated in a predetermined operation mode;
Torque margin formation for controlling the first torque parameter to the torque increasing side by the torque margin from the target torque while the operation mode determining means determines that the vehicle is operating in the predetermined operation mode. Means,
An engine torque control device according to any one of claims 1 to 7.   The engine torque control device according to claim 8, wherein the predetermined operation mode is an operation mode indicating an idling operation.   The engine torque control device according to any one of claims 1 to 9, wherein the torque margin is determined as an offset amount from a reference torque that becomes a torque peak. The engine is a spark ignition engine;
The second torque parameter is an ignition timing of the spark ignition engine,
The reference torque is an optimum ignition timing (MBT) corresponding to an ignition timing at which the largest engine torque is obtained in one fuel cycle,
The engine torque control device according to claim 10, wherein the offset amount is a retard amount from the optimum ignition timing. The engine is a spark ignition engine;
The first torque parameter is an intake air amount with respect to a cylinder of the engine;
The engine torque control device according to any one of claims 1 to 11, wherein the second torque parameter is an ignition timing of the spark ignition type engine. The first torque parameter related to the magnitude of the torque of the engine to be controlled, and the second torque parameter that acts on the engine torque with higher responsiveness than when the first torque parameter is changed, In order to maintain or form a state where a predetermined torque margin is provided on the torque increase side of the torque parameter, the shortage due to the torque margin is supplemented with the first torque parameter to comprehensively calculate the actual torque of the engine output. An adjustment method for an engine torque control device for controlling the torque to a target torque,
An engine characterized by obtaining the torque margin based on a maximum acceleration limit amount of engine rotation speed, which is a maximum acceleration amount that can be accelerated per unit time, and setting the torque margin in the engine torque control device. Adjustment method of torque control device.

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