JP2011038477A - Control device of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine torque control means capable of effectively preventing a stick-slip under every operating condition, while exhibiting sufficiently a high potential of torque responsiveness in a variable valve gear engine. <P>SOLUTION: A target torque trajectory is changed as appropriate during acceleration and deceleration period, based on rate-determining condition relating to vehicle performance such as stick-slip or torque linearity, while considering relative relationship between a maximum torque trajectory and a target torque trajectory that may occur during acceleration and deceleration. In other words, a control device of an engine mounted on a vehicle, the control device of engine calculates a maximum torque trajectory that can be realized during transient operations such as acceleration or deceleration in advance, and determines the target torque trajectory based on a margin composed of a difference between the calculated maximum torque trajectory and the target torque trajectory. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an engine control device mounted on a vehicle.

  2. Description of the Related Art In recent years, a variable valve engine having a variable mechanism for valve timing and valve lift and capable of intake air control and thus torque control without throttle has been put into practical use. The variable valve engine features low fuel consumption due to the pump loss reduction effect, and intake control is performed with a valve close to the combustion chamber. Therefore, high-speed intake (torque) response, etc. compared to conventional intake control using the throttle There is an advantage that can be obtained.

  On the other hand, if a vehicle is suddenly accelerated or suddenly decelerated by a sudden accelerator operation, vehicle longitudinal vibration may occur due to torsion of a drive system such as a drive shaft caused by a sudden change in engine torque. Such vehicle longitudinal vibration is generally called “shakuri” and is a phenomenon that should be prevented because it reduces drivability. In order to essentially prevent the occurrence of shackle, the amount of change in engine torque during acceleration / deceleration should be set small so as to suppress torsion of the drive system. However, when the change amount of the engine torque is simply reduced, there is a problem that the torque response is deteriorated.

  Several techniques for ensuring torque responsiveness while preventing the shackle are disclosed. For example, Patent Document 1 is known as a known technique (FIGS. 12 and 13). In the sequence of engine torque trajectory setting at the time of acceleration / deceleration shown in this publication, first, an engine torque (hereinafter, balance torque) at which the engine is in an upright position with respect to the engine mount is obtained in advance. Next, when the engine torque generated during acceleration / deceleration approaches the balance torque, the rate of increase / decrease in engine torque per unit time is limited so that the engine torque remains in the vicinity of the balance torque for a certain period. Finally, after the engine torque passes near the balance torque, the engine torque increase / decrease rate is relaxed and the engine torque is increased / decreased again. This technology mitigates engine run-out during sudden acceleration / deceleration, optimizes the torque input value applied to the drive system after the engine run-off has converged, prevents shackles due to drive system torsion, and prevents accelerator operation. The effect of achieving good torque response can be obtained.

JP 2006-242090 A

  Due to problems such as valve control accuracy, the current variable valve engine does not achieve complete throttle-less operation, and must switch to intake control using the throttle when the load is low, the engine is cold, or the brake negative pressure is low. There may not be. That is, the intake control by the throttle and the variable valve is mixed. In this case, since the intake (torque) response is different in the intake control using the throttle and the variable valve, it is desirable to set the target torque trajectory according to each characteristic. However, the technique described in Patent Document 1 is intended only for a conventional engine that performs torque control by a throttle, and is not sufficiently considered for application to a variable valve engine.

  The present invention has been made in view of the above problems, and is an engine torque control capable of effectively preventing the occurrence of shackles in any operating state while sufficiently extracting a high torque response potential in a variable valve engine. It is to provide means.

  As shown in FIG. 14, in intake (torque) control of the throttle and the variable valve, there is a difference in intake (torque) response when each actuator is moved at the fastest speed, and the maximum engine torque trajectory that can be generated during a transient Is different. The target torque trajectory during acceleration / deceleration should be set within a range that does not exceed the maximum torque trajectory that can be generated during the transition (hereinafter referred to as the maximum torque trajectory during transient). The degrees of freedom vary greatly. Compared to the throttle, torque control using variable valves has a greater degree of freedom in setting the target torque trajectory, and there is more room for changing the trajectory, but the change must be implemented with due consideration to factors related to drivability. There is.

  For example, as shown in FIG. 15, when increasing the torque increase rate before passing the balance torque (before the engine is fixed to the engine mount during acceleration / deceleration), as described above, the increase in the torque increase rate in this phase is as follows. Since this leads to an increase in engine run-out during acceleration / deceleration, both the torque control using the throttle and the variable valve is likely to cause a shackle.

  On the other hand, as shown in FIG. 16, when the torque increase rate after passing the balance torque (after the engine is fixed to the engine mount) is increased in consideration of the reduction of shackle, torque control by a throttle with low torque response is used. In the middle of the torque increase, the transient maximum torque trajectory is reached. As a result, an inflection point occurs in the target torque trajectory, and the torque linearity deteriorates. On the other hand, in torque control using a variable valve, the opening width between the target torque trajectory and the maximum generated torque trajectory at the time of transient (hereinafter referred to as torque margin) is large. There is no linearity problem.

  In other words, the greater the torque margin, the greater the degree of freedom in changing the target torque trajectory. Therefore, it is required to set the target torque trajectory in consideration of these.

  As described above, as a target torque trajectory setting method corresponding to a variable valve engine, a vehicle such as a shackle or torque linearity is considered while taking into account the relative relationship between the maximum torque trajectory that can be generated during acceleration and deceleration and the target torque trajectory. By appropriately changing the target torque trajectory during the acceleration / deceleration period based on the constraint conditions related to the performance, it is possible to always draw out a potential with high torque response in the variable valve engine.

  As described above, by optimizing the engine torque trajectory at the time of transition, taking into account the reduction of engine vibration during sudden acceleration / deceleration of the automobile and the torque input value applied to the drive system after convergence of engine vibration It is possible to improve the drivability by preventing the vehicle longitudinal vibration caused by the twist of the drive system.

The figure which shows the hardware constitutions of a torque base type engine control system. The whole control block diagram of torque base type engine control in the 1st example. The figure which showed the relationship between the opening / closing timing of a valve, and a valve profile. The figure which shows the calculation content of the demand torque calculation means 204 at the time of acceleration in a 1st Example. The figure shown about the relationship between an accelerator opening and a driver request torque. The figure which shows the content of the torque increase amount upper limit table used for the dynamic limit process of high response target torque calculation in a 1st Example. The figure which shows the behavior of each calculation parameter at the time of acceleration at the time of selecting the intake control by a throttle in a 1st Example. The figure which shows the relationship between an ignition retard amount and a torque generation rate. The figure which shows the behavior of each calculation parameter at the time of acceleration at the time of selecting the intake control by a variable valve in a 1st Example. The figure which shows the calculation content of the demand torque calculation means 204 at the time of acceleration in the 2nd Example. The figure which shows the content of a driver preference reflection means. The figure which showed the relationship between a target engine torque track | orbit and an engine position. The figure shown about the change of axle driving force at the time of shifting from deceleration to acceleration. The figure which shows the difference in the intake (torque) responsiveness in a throttle and a variable valve. The figure which shows the relationship between the largest torque trajectory which can be implement | achieved, and a target torque trajectory. The figure which shows the relationship between the largest torque trajectory which can be implement | achieved, and a target torque trajectory.

  Embodiments according to the present invention will be described in detail below. FIG. 1 is a diagram showing a hardware configuration of a torque-based engine control system for homogeneous stoichiometric combustion that operates near the stoichiometric air-fuel ratio, which is a first embodiment according to the present invention, and FIG. 2 corresponds to this hardware configuration. FIG. 5 is a control block diagram of torque-based engine control.

First, the hardware configuration will be described with reference to FIG. The intake air taken in from the intake pipe 101 passes through the air cleaner 100, and after the intake air amount is measured by the airflow sensor 102 provided in the intake pipe 101, the intake air amount and the intake pipe negative pressure are adjusted. The electronic control throttle valve (hereinafter referred to as the electric throttle 103) is introduced into the inlet. The measured value of the airflow sensor 102 is transmitted to an engine control unit (hereinafter referred to as ECU 116), and the fuel injection pulse width of the injector 105 is calculated based on this value so that the air-fuel ratio becomes the stoichiometric air-fuel ratio. The intake air that has passed through the electric throttle 103 is introduced into the intake manifold after passing through the collector 104, and is mixed with the gasoline spray injected from the injector 105 in accordance with the fuel injection pulse width signal to form an air-fuel mixture. It is introduced into the combustion chamber 109 in synchronism with the opening and closing of the intake valve 106 driven by 120. Thereafter, the intake valve 106 is closed, and the air-fuel mixture compressed in the process of ascending the piston 110 is ignited by the spark plug 107 according to the ignition timing commanded by the ECU in the vicinity immediately before the compression top dead center, and rapidly expands. The piston 110 is pushed down to generate engine torque. Thereafter, the piston 110 ascends and the exhaust stroke starts from the moment when the exhaust valve 108 driven by the variable exhaust camshaft 121 is opened, and the exhaust gas is discharged to the exhaust manifold 111. A three-way catalyst 113 for purifying the exhaust gas is provided downstream of the exhaust manifold 111. When exhaust gas passes through the three-way catalyst 113, the exhaust components of HC, CO, and NOx are H ₂ O, CO ₂ , N Converted to ₂ . A wide-range air-fuel ratio sensor 112 and an O ₂ sensor 114 are installed at the three-way catalyst inlet and outlet, respectively, and the air-fuel ratio information measured by these sensors is transmitted to the ECU 116. The ECU 116 performs air-fuel ratio feedback control by adjusting the fuel injection amount so that the air-fuel ratio becomes close to the theoretical air-fuel ratio based on such information. Note that the opening degree of the electric control throttle 103 and the command values to the variable intake camshaft 120 and the variable exhaust camshaft 121 are set based on a target engine torque calculated in the ECU described later. Further, the fuel injection pulse width may be set to 0 depending on the cylinder number (fuel cut) according to the target engine torque. Similarly, the ignition timing is usually set to MBT (ignition timing at which the engine torque can be generated most), but may be set to a delay side according to the target engine torque (ignition retard).

  Next, an overall control block of torque-based engine control corresponding to this hardware configuration will be described with reference to FIG. This engine control is mainly composed of target torque calculation means 201 and target torque realization means 202. In the target engine torque calculation means 201, a driver request torque calculation means 203 for calculating the most basic request torque corresponding to the driver's accelerator operation, and an operation state determination means 208 are installed. The driver request torque calculation means 203 calculates the engine torque requested by the driver based on the engine speed, the maximum torque, and the idle request torque in addition to the accelerator opening. The driving state determination means 208 determines the driving state under the circumstances from the accelerator opening, vehicle speed, presence / absence of external required torque, water temperature, and the like. The driver requested torque calculation means 203 is followed by a transitional time such as a required torque during acceleration, a required torque during deceleration, a required torque during fuel cut, a required torque during fuel cut recovery, etc. calculated based on the required driver torque. A required torque calculation means group for improving drivability is installed. Further, a target torque selecting means 209 is installed in the subsequent stage, and the optimum demand for the vehicle is determined according to the determination result of the driving state determining means 208 from the required torque group and the external required torque such as traction control and cruise control. Torque is selected, two types of target engine torque (low response target torque 210, high response target torque 211), and an estimated value of the engine torque when it is assumed that only intake control is performed. Is output.

  In the target torque realization means 202, low response target torque realization means 213 necessary for realizing low-speed torque control by an intake system actuator (electric throttle 103, variable intake camshaft 120, variable exhaust camshaft 121) and In addition, there is a high response target torque realizing means 214 necessary for realizing high-speed torque control by ignition retard or fuel cut. In the low response target torque realization means 213, a target intake air amount and a target intake pipe negative pressure calculation means 215 are installed, and the target intake air amount and the target intake pipe negative pressure necessary for realizing the low response target torque 210 are obtained. calculate. In the subsequent stage, target throttle opening degree calculation means 216 for realizing the target intake air amount and the target intake pipe negative pressure, and target valve timing and lift amount calculation means 230 are installed, and a desired target throttle opening degree 217 and After the intake valve opening / closing timing target values (231, 232) and the exhaust valve opening / closing timing target values (233, 234) are calculated, they are transmitted to the electric throttle, the variable intake camshaft 120, and the variable exhaust camshaft 121, respectively.

  As described above, there are two systems of intake devices for realizing the target intake air amount, namely, the electric throttle 103 and the variable valve (variable intake camshaft 120, variable exhaust camshaft 121). Is determined according to the operating state determination means 208.

  When intake control is performed using a variable valve, as shown in FIG. 3, an intake valve opening timing target value (IVO), an intake valve closing timing target value (IVC), an exhaust valve opening timing target value (EVO), By specifying the exhaust valve closing timing target value (EVC), the opening / closing profile of the intake valve and the opening / closing profile of the exhaust valve are uniquely determined, and desired intake control can be performed.

  On the other hand, in the high response target torque realizing unit 214, a desired torque operation ratio is calculated by the torque operation amount distribution calculating unit 219 based on the torque correction rate 218 obtained by dividing the high response target torque 211 by the estimated intake air equivalent torque 212. Is calculated, and the target torque operation ratio is transmitted to the ignition retard amount calculating means 220 and the fuel cut cylinder number calculating means 222. The ignition retard amount calculation means 220 calculates the ignition retard amount 221 according to the transmitted ignition share torque operation ratio, and transmits the calculation result to the ignition timing control calculation means. On the other hand, the fuel cut cylinder number calculating means 222 calculates the fuel cut cylinder number 223 according to the similarly transmitted fuel share torque operation ratio, and transmits the calculation result to the fuel injection control calculating means. The torque operation ratio ignition and fuel burden ratio are determined according to the operating state determination means 208.

  Next, a first embodiment will be described with reference to FIGS. FIG. 4 shows details of each parameter calculation in the acceleration required torque calculation means 204 when the acceleration determination is made by the driving state determination means 208 and the acceleration required torque calculation means 204 is selected. As described above, the driver required torque calculation means 203, which is the starting point for calculating the acceleration required torque, calculates the required torque according to the driver's accelerator operation based on the maximum torque and the idle required torque at the engine speed at that time. To do. Specifically, as shown in FIG. 5, the required torque is calculated so as to realize a torque characteristic substantially equivalent to that of the mechanical throttle + ISC valve system. In other words, the required idle torque is calculated when the accelerator is fully closed, and the required torque is gradually increased so as to protrude upward as the accelerator opening increases. Finally, when the accelerator is fully open, the maximum torque at the engine speed is calculated. Is.

  The acceleration required torque calculation means 204 calculates an acceleration low response request torque, an acceleration high response request torque, and an intake intake equivalent estimated torque based on the driver request torque and a balance torque described later. The balance torque is an engine torque value required for the engine to maintain an upright state with respect to the engine mount. The acceleration balance torque calculation means 304 receives the vehicle speed, gear position, and friction torque as input, and performs a table search. The balance torque during acceleration is calculated. As a method of adapting the balance torque, the engine is almost upright with respect to the engine mount during steady R / L travel. Therefore, R / L steady travel is performed for each engine operating region defined by the vehicle speed and gear position. The engine torque at the time may be measured, and correction may be made so that desired drivability at the time of acceleration / deceleration can be obtained based on the engine torque during steady running.

  First, regarding the calculation of the low response request torque during acceleration necessary for the low response torque control such as the electric throttle 103 and the variable valve control, the driver target torque is calculated in the low response request torque calculation unit 301 during acceleration. It is output as the low response required torque during acceleration as it is, and is used for electric throttle and variable valve control.

  Next, the calculation contents of the intake equivalent estimated torque and the acceleration high response required torque necessary for high response torque control such as ignition retard and fuel cut will be described. The intake equivalent estimated torque is calculated by the intake equivalent estimated torque calculating means 303 in consideration of the intake system actuator delay and intake charge / release delay caused by the intake pipe volume. On the other hand, the estimated torque corresponding to the intake air is calculated by performing the delay process. As a specific delay processing method, in this embodiment, dead time + first order delay processing based on actual machine data is performed. However, a physical model of the electric throttle 103, variable valve, and intake pipe 101 is constructed, The delay may be calculated theoretically.

Next, the acceleration high response request torque calculating means 302 performs dynamic limit processing on the estimated intake equivalent torque that is the base of the acceleration high response request torque to calculate the acceleration high response request torque. The dynamic limit processing is to set an upper limit value of the torque increase amount per unit time, and to control the torque increase amount per unit time of the acceleration high response required torque so as not to exceed the upper limit value. is there. In particular,
(1) A torque difference between the acceleration high-response required torque basic value [previous value] and the balance torque is obtained, and a torque increase upper limit value corresponding to the torque difference is determined by a torque increase upper limit table as shown in FIG. calculate.
(2) A torque increase amount (= intake equivalent estimated torque−acceleration high response required torque basic value [previous value]) is obtained, and the following calculation is performed.
a) When the torque increase is equal to or less than the torque increase upper limit value Acceleration high response required torque basic value = Intake equivalent estimated torque (current value)
b) When torque increase> Torque increase upper limit value High-response required torque basic value during acceleration = High-response required torque basic value during acceleration [previous value] + Upper limit value of torque increase (3) Finally, high response during acceleration Select low processing is performed for the required torque basic value and the estimated torque corresponding to the intake air (current value), and the final high response required torque during acceleration is calculated.

  Next, the behavior of each parameter related to the acceleration required torque during acceleration when the electric throttle 103 is selected as the intake system actuator will be described with reference to FIG. Acceleration is started by the driver's accelerator operation, the accelerator opening increases, the driver request torque and the low response target torque increase, and the throttle opening in the electric throttle 103 increases in conjunction with it. As the throttle opening increases, the intake air amount increases, and the engine torque corresponding to the intake air as shown in FIG. 7 rises.

  On the other hand, in parallel with the above, the high response target torque is separately calculated so as to achieve both prevention of vehicle longitudinal vibration during acceleration and good accelerator response. Specifically, by applying the dynamic limit process to the estimated torque corresponding to the intake air, the rate of increase in torque per unit time is sequentially controlled according to the acceleration phase, and a high response target torque trajectory as shown in FIG. calculate. That is, the high response target torque gradually increases in the early stage of acceleration, and when the high response target torque approaches the balance torque under this situation when the acceleration is in the middle, the torque increase upper limit value is set to be extremely small by the calculation process, Increase rate of high response target torque decreases. After that, after the high response target torque gently passes around the balance torque, the high response target torque turns to an appropriate torque increase rate as the torque increase upper limit is relaxed again, and finally the driver request torque Reach value.

  As shown in FIG. 7, the high response target torque often draws a geometric target torque trajectory and is difficult to realize by torque control using only the electric throttle 103. Therefore, the engine torque corresponding to the intake air that is expected to be realized by torque control of only the electric throttle 103 is estimated by the intake air equivalent estimated torque calculation means 303, and the estimated torque and the high response target torque are calculated. If there is a difference, a high response torque operation (high speed torque operation by ignition retard in acceleration) is performed so as to fill the difference. Specifically, the following torque correction rate 218 calculation is performed as an index for obtaining a difference (ratio) between the high response target torque and the estimated intake equivalent torque.

Torque correction ratio = high response target torque ÷ intake equivalent estimated torque The torque correction ratio takes a value of 0 to 1, and if the torque correction ratio = 1, no high response torque operation is required, for example, torque correction ratio = 0. 7 means that the torque is reduced by 30% by the high response torque operation. Using the correction rate as an input, the torque manipulated variable distribution calculating means 219 transmits the torque correction rate 218 to the ignition and fuel in consideration of the torque correction burden ratio to the ignition and fuel, respectively. During acceleration, since torque operation with fuel is not performed, the torque correction rate 218 is transmitted as it is to the ignition retard amount calculation means 220, and the ignition retard amount calculation means 220 is based on the relationship as shown in FIG. Then, the ignition retard amount 221 capable of performing the desired torque correction is calculated.

  Immediately after the engine is fixed, the target torque setting means and the target torque realizing means as described above are used to control the torque so that the engine shake during acceleration is moderated and the shock when the engine is fixed is reduced. It is possible to optimize the rate of increase of torque in the engine and prevent a sudden rise in torque applied to the drive system. As a result, it is possible to achieve both prevention of vehicle longitudinal vibration during acceleration and good accelerator response.

  Next, the behavior of each parameter related to the required torque during acceleration at the time of acceleration when a variable valve is selected as the intake system actuator will be described with reference to FIG. The sequence of control is the same as when the electric throttle is selected, but the torque increase rate when increasing the high response target torque after the high response target torque has gently passed through the vicinity of the balance torque, It is set larger than when the electronic throttle is selected. This is because the intake valve control with a variable valve excels in the intake response compared to the intake control with the throttle, so the high response target torque near the balance torque and the intake equivalent amount corresponding to the maximum torque that can be achieved during acceleration. This is because the difference from the estimated torque is large, and even if the torque increase / decrease rate of the high response target torque after passing the balance torque is increased, problems such as the target torque trajectory being broken are unlikely to occur. As a result, linear and stretchable acceleration can be achieved while preventing shackles, and the torque response potential of the variable valve can be maximized.

  Next, a second embodiment of the present invention will be described with reference to FIG. The difference of the second embodiment from the first embodiment is that a driver preference reflecting means 401 is provided in the high response torque calculating means. FIG. 11 shows details of the driver preference reflecting means 401. As described above, the torque control by the variable valve can perform the high-response torque control. However, since the characteristic is not necessarily desired by the driver, the driver preference reflecting means 401 is provided to provide the high-response torque control. Can be selected according to the driver's preference. Input includes various mode selection switches such as sports mode and economy mode, and history information of driver's accelerator operation, etc. Even when a variable valve is selected as an intake system actuator, high response torque control is uniformly performed. Whether or not execution is possible is determined based on the input information related to the driver's preference without executing. By introducing this calculation means, the merchantability of the variable valve engine can be further improved without causing the driver to feel uncomfortable or uncomfortable.

100 air cleaner 101 an intake pipe 102 flow sensor 103 electronically controlled throttle 104 collector 105 injector 106 intake valve 107 spark plug 108 exhaust valve 109 combustion chamber 110 piston 111 exhaust manifold 112 wide-range air-fuel ratio sensor 113 three-way catalyst 114 O ₂ sensor
115 Accelerator pedal sensor 116 ECU
120 Variable intake camshaft 121 Variable exhaust camshaft 201 Target torque calculating means 202 Target torque realizing means 203 Driver required torque calculating means 204 Required torque calculating means during acceleration
205 Required torque calculation means 206 during deceleration 206 Required torque calculation means 207 during fuel cut Required torque calculation means 208 during fuel cut recovery 208 Operating state determination means
209 Target torque selection means 210 Low response target torque 211 High response target torque
212 Intake equivalent estimated torque 213 Low response target torque realization means 214 High response target torque realization means 215 Target intake air amount and target intake pipe negative pressure calculation means 216 Target throttle opening degree calculation means 217 Target throttle opening degree 218 Torque correction rate 219 Torque Operation amount distribution calculating means 220 Ignition retard amount calculating means 221 Ignition retard amount 222 Fuel cut cylinder number calculating means 223 Fuel cut cylinder number 230 Target valve timing and lift amount calculating means 231 Intake valve opening timing target value (IVO)
232 Intake valve closing timing target value (IVC)
233 Exhaust valve opening timing target value (EVO)
234 Exhaust valve closing timing target value (EVC)
301 Acceleration low response request torque calculation means 302 Acceleration high response request torque calculation means 303 Intake equivalent estimated torque calculation means 304 Acceleration balance torque calculation means 401 Driver preference reflection means 402 High response torque control execution enable / disable command 403 Sports / economy Travel determination means 404 Accelerator operation history analysis means 405 High response torque control execution possibility determination means

Claims (7)

  A control device for an engine mounted on a vehicle that calculates in advance the maximum torque trajectory that can be realized during transient operation such as acceleration and deceleration, and has a margin of difference between the calculated maximum torque trajectory and the target torque trajectory. An engine control apparatus that determines the target torque trajectory based on the target torque trajectory.   2. The engine control apparatus according to claim 1, wherein the transient operation period is divided into a plurality of periods, and a rate of increase / decrease of the target torque trajectory is changed for each period.   3. The engine control apparatus according to claim 2, further comprising balance torque calculation means for obtaining an engine torque (balance torque) at which the engine is in an upright state when the vehicle is accelerated or decelerated, and the engine is generated during the acceleration / deceleration. The torque change amount per unit time of the torque generated by the engine when the torque passes near the balance torque obtained by the balance torque calculating means is set smaller than other engine torque regions. Engine control device.   4. The engine control device according to claim 3, wherein a torque change amount per unit time after passing near the balance torque according to claim 3 is variable in accordance with a difference from the maximum torque trajectory.   The engine according to claim 1, wherein either an throttle or a variable valve system is used as an intake control device.   The engine control device according to claim 4, wherein whether or not the torque change amount per unit time can be changed is determined based on preference information relating to a driver's engine torque responsiveness.   7. The engine control apparatus according to claim 6, wherein the driver preference information is determined based on a mode selection switch relating to engine torque response or accelerator operation information.

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