JP2005163672A - Torque control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a torque control device for an internal combustion engine capable of making acceleration performance compatible with vehicle body front/rear vibration suppression in a balanced manner. <P>SOLUTION: This torque control device for the internal combustion engine controls output torque of the internal combustion engine mounted to a vehicle, and is provided with an accelerator opening detection means, an engine speed detection means, a torque prediction means for predicting a torque curve of required torque based on an accelerator opening and engine speed, an acceleration prediction means for predicting vehicle front/rear acceleration based on the predicted torque curve, and a torque control means for controlling engine output torque. The torque control means adjusts the torque curve so as to generate the maximum torque within the range where a peak value of the front/rear acceleration predicted by the acceleration prediction means does not exceed a predetermined allowable value, and controls the output torque. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a torque control device for an internal combustion engine that controls output torque of the internal combustion engine.

In a vehicle using an internal combustion engine (engine) as a power source, if the engine torque is suddenly raised when the accelerator pedal is depressed by the driver, the torsional vibration of the drive system (especially the drive shaft) is excited and the vehicle body Vibration occurs. For this reason, in the invention described in [Patent Document 1] and the like, the longitudinal vibration generated in the vehicle is suppressed by retarding the ignition timing and reducing the output torque during acceleration. Further, after the torque reduction is continued for a predetermined period, ignition timing control for generating torque having a phase opposite to that of the longitudinal vibration is also performed to suppress the longitudinal vibration of the vehicle body.
JP-A-5-321803

  However, since the output torque is suppressed by retarding the ignition timing, it is possible to prevent longitudinal vibrations of the vehicle body, but there is a problem that acceleration cannot be performed quickly due to vehicle motion performance. Accordingly, an object of the present invention is to provide a torque control device for an internal combustion engine that can achieve both acceleration and vehicle body longitudinal vibration suppression in a well-balanced manner.

  The invention according to claim 1 is a torque control device for an internal combustion engine for controlling an output torque of an internal combustion engine mounted on a vehicle, and includes an accelerator opening detecting means for detecting an amount of depression of an accelerator pedal, and rotation of the internal combustion engine. A rotation number detection means for detecting the number, and a torque prediction means for predicting a torque curve of the required torque based on the accelerator opening detected by the accelerator opening detection means and the rotation speed detected by the rotation detection means An acceleration prediction means for predicting longitudinal acceleration generated in the vehicle based on the torque curve predicted by the torque prediction means, and an internal combustion engine by controlling at least one of the intake air amount, the injected fuel amount, and the ignition timing Torque control means for controlling the output torque of the engine, and the torque control means includes a peak of longitudinal acceleration predicted by the acceleration prediction means. There has been and controls the adjustment to output torque of the torque curve to generate the maximum torque in a range that does not exceed the permissible value set in advance.

  The torque control device for an internal combustion engine according to claim 2 controls the output torque of the internal combustion engine mounted on the vehicle, and includes an acceleration detection means for detecting longitudinal acceleration generated in the vehicle, an intake air amount, Torque control means for controlling the output torque of the internal combustion engine by controlling at least one of the injected fuel amount and the ignition timing, and the torque control means has a longitudinal acceleration detected by the acceleration detection means as a predetermined value. The maximum torque is generated until reaching the value, and after the longitudinal acceleration reaches a predetermined value, the output torque is adjusted so as to decrease the output torque for a predetermined period.

  According to a third aspect of the present invention, in the torque control device for an internal combustion engine according to the second aspect, the accelerator opening degree detecting means for detecting the depression amount of the accelerator pedal, and the rotational speed detecting means for detecting the rotational speed of the internal combustion engine. And a target torque calculating means for calculating a target torque based on the accelerator opening detected by the accelerator opening detecting means and the rotational speed detected by the rotational speed detecting means. The maximum torque is generated until the longitudinal acceleration detected by the detection means reaches the longitudinal acceleration that occurs during steady running at the target torque, and after the longitudinal acceleration reaches the target torque, the engine torque is reduced below the target torque for a predetermined period. The output torque is adjusted so that

  The maximum torque in the above-described invention means the engine torque that is the upper limit at which the vehicle (wheel) does not cause a slip. However, if slip does not occur at the maximum torque that the internal combustion engine can output, the maximum torque means the maximum torque that the internal combustion engine can output.

  In the torque control apparatus for an internal combustion engine according to claim 1, a torque curve is predicted based on the detected accelerator opening and the engine speed, and further, longitudinal acceleration (longitudinal vibration) generated in the vehicle based on the torque curve. Predict. Then, torque control is actually performed to generate the maximum torque at which the predicted peak value of the longitudinal acceleration does not exceed the allowable value. For this reason, the longitudinal vibration of the vehicle is suppressed by limiting the predicted longitudinal acceleration to a range that does not exceed the allowable value. Further, since the torque control is performed so that the maximum torque is generated within a range where the longitudinal acceleration does not exceed the allowable value, the acceleration performance is not sacrificed. By doing in this way, acceleration performance and vehicle body longitudinal vibration suppression can be achieved in a well-balanced manner.

  In the torque control device for an internal combustion engine according to claim 2, the longitudinal acceleration generated in the vehicle is detected, and it is sufficient to generate the maximum torque until the longitudinal acceleration reaches a predetermined value. Acceleration performance can be obtained. When the detected longitudinal acceleration reaches a predetermined value, the output torque is reduced for a predetermined period to suppress the longitudinal vibration of the vehicle. By doing in this way, acceleration performance and vehicle body longitudinal vibration suppression can be achieved in a well-balanced manner.

In the invention described in claim 3, in the torque control means described in claim 2 described above, a target torque is calculated based on the detected accelerator opening and engine speed, and steady running is performed with this target torque. The longitudinal acceleration generated at the time of occurrence is set to the predetermined value described above. Then, the maximum torque is generated until the longitudinal acceleration generated in the vehicle reaches the steady acceleration, and when the steady acceleration is reached, the output torque is reduced below the target torque to suppress the longitudinal vibration of the vehicle. By doing in this way, it is possible to effectively balance acceleration performance and vehicle body longitudinal vibration suppression with a good balance.
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  A first embodiment of the control device of the present invention will be described below. An engine 1 having a control device of the present embodiment is shown in FIG. An engine (internal combustion engine) 1 described in the present embodiment is a multi-cylinder engine, but only one cylinder is shown in FIG. 1 as a cross-sectional view. In the engine 1, the outside air (intake air) taken through the intake passage 2 and the fuel injected from the injector 3 are mixed to form an air-fuel mixture, and the air-fuel mixture is compressed by the piston 5 in the cylinder 4 and then the spark plug 6. Ignite and burn. The pressure increase in the cylinder 4 due to combustion is taken out as an output through the piston 5 and the connecting rod. The inside of the cylinder 4 and the intake passage 2 are opened and closed by an intake valve 7, and the inside of the cylinder 4 and the exhaust passage 8 are opened and closed by an exhaust valve 9.

  On the intake passage 2, an air cleaner 10, an air flow meter 11, a throttle valve 12, and the like are arranged from the upstream side. The air cleaner 10 is a filter that removes dust and dirt in the intake air. The air flow meter 11 of this embodiment is of a hot wire type, and detects an intake air amount as a mass flow rate. The throttle valve 12 of this embodiment is a so-called electronically controlled throttle valve. The operation amount of the accelerator pedal 13 is detected by the accelerator position sensor 14, and the electronic control unit (ECU) 15 determines the opening degree of the throttle valve 12 based on the detection result and other information amounts. The throttle valve 12 is opened and closed by a throttle motor 16 that is provided in association therewith. Along with the throttle valve 12, a throttle positioning sensor 17 for detecting the opening degree is also provided.

  The ECU 15 adjusts the output torque of the engine 1 by adjusting the opening degree of the throttle valve 12 described above, the fuel injection amount injected from the injector 3, the ignition timing of the air-fuel mixture by the spark plug 6, and the like. That is, the ECU 15 functions as a torque control unit. The adjustment of the output torque may be performed by combining the above-described parameters, or may be performed by any one of them. Further, the accelerator position sensor 14 functions as an accelerator opening detecting means for detecting an operation amount (accelerator opening) of the accelerator pedal 13.

  On the other hand, an exhaust purification catalyst 18 is disposed on the exhaust passage 8. A temperature sensor 19 for detecting the temperature is attached to the exhaust purification catalyst 18. An oxygen sensor 20 is also attached upstream of the exhaust purification catalyst 18. The oxygen sensor 20 detects the oxygen concentration in the exhaust gas flowing into the exhaust purification catalyst 18. The air-fuel ratio is detected by detecting the oxygen concentration in the exhaust gas. The temperature sensor 19 and the oxygen sensor 20 are connected to the ECU 15 described above. The ECU 15 is responsible for overall engine control and comprises a CPU, ROM, RAM, and the like.

  A crank position sensor 21 for detecting the engine speed and the piston position is attached in the vicinity of the crankshaft of the engine 1. The crank position sensor 21 functions as a rotational speed detection unit that detects the engine rotational speed of the engine 1. In addition, an acceleration sensor 22 that detects longitudinal acceleration generated in the vehicle is also attached. A wheel speed sensor 24 is also attached to each wheel of the vehicle, and the vehicle speed of the vehicle can also be detected. Further, a water temperature sensor 23 for detecting the cooling water temperature of the engine 1 is also attached to the engine block (cylinder block). These crank position sensor 21, acceleration sensor 22, water temperature sensor 23, and wheel speed sensor 24 are also connected to the ECU 15.

  The ECU 15 also functions as torque predicting means for predicting a time history (torque curve) of torque to be output by the engine 1 from the accelerator opening and the engine speed in the control described later. The ECU 15 also functions as acceleration prediction means for predicting longitudinal acceleration generated in the vehicle from the torque curve in the control described later. Further, the ECU 15 also functions as a target torque calculation means for calculating a target torque that the engine 1 should output from the accelerator opening and the engine speed. Note that the torque curve predicted as the torque predicting means converges to the target torque calculated as the target torque calculating means.

  Next, each embodiment of torque control by the torque control device of the present invention will be described. First, a first embodiment will be described. 2 and 3 show control flowcharts of the present embodiment. As described above, when the engine torque is suddenly raised when the accelerator pedal 13 is depressed by the driver, the torsional vibration of the drive system (especially the drive shaft) is excited and longitudinal vibration is generated in the vehicle body. This longitudinal vibration can be avoided if the engine torque is raised smoothly, but acceleration cannot be performed quickly. In the control by the torque control device according to the present embodiment, first, how to generate torque (torque curve) is predicted from various amounts of information, and based on this torque curve, acceleration performance is further improved within a range in which longitudinal vibration can be tolerated. Determine the final torque curve while judging whether or not In this way, torque control that balances acceleration and vehicle body longitudinal vibration suppression in a well-balanced manner is performed.

  As shown in FIG. 2, first, the accelerator position sensor 14 detects the depression amount (accelerator opening) θ of the accelerator pedal 13 (step 200). Further, the accelerator opening θ detected by the ECU 15 is integrated over time to calculate an accelerator depression speed dθ / dt, and it is determined whether or not the accelerator depression speed dθ / dt exceeds a predetermined value α (step 205). ). The predetermined value α is set as a threshold value for determining whether or not torque control of the engine 1 needs to be performed while balancing acceleration performance and vehicle body longitudinal vibration suppression. In other words, if the accelerator depressing speed dθ / dt is equal to or less than the predetermined value α, the vehicle body longitudinal vibration that causes a problem does not occur, and therefore only normal torque control may be performed.

  On the contrary, when the accelerator depression speed dθ / dt exceeds the predetermined value α, it can be said that the vehicle longitudinal vibration may become a problem when acceleration is performed simply considering only the acceleration performance. In such a case, torque control is performed by balancing acceleration performance and vehicle longitudinal vibration suppression. Therefore, if it can be determined that the vehicle body longitudinal vibration which is a problem cannot be generated when the accelerator depression speed dθ / dt is equal to or less than the predetermined value α, only normal torque control may be performed.

  That is, when step 205 is negative, normal torque control is performed to adjust the output torque of the engine 1 using the opening θth of the throttle valve 12 and the ignition timing SA as parameters (step 210). On the other hand, when step 205 is affirmed, first, the engine speed Ne is detected by the crank position sensor 21 in order to perform torque control of the engine 1 while balancing acceleration performance and vehicle body longitudinal vibration suppression, The ratio is also detected (step 215). Next, the ECU 15 calculates the target torque Ts of the engine 1 from the map based on the accelerator opening θ detected in step 200 and the engine speed Ne detected in step 215 (step 220).

  This target torque Ts is a torque that finally converges the output torque of the engine 1. When the torque is actually output, the generation state of the vehicle longitudinal vibration changes depending on how the torque is generated until the torque is reached (in other words, the torque curve). The map used here is shown in FIG. As shown in FIG. 4, there are a plurality of target torque curves for each accelerator opening θ, and the value on the vertical axis corresponding to the intersection between this and the engine speed Ne is the target torque Ts. Next, a time ts until the target torque Ts is finally reached after the start of control is determined. FIG. 5 shows a torque curve in the case where the torque is increased linearly until time ts and finally made steady at the target torque Ts. That is, a basic torque curve can be defined by the target torque Ts and the time ts.

  An arbitrary value may be given as an initial value for this time ts, and in this embodiment, ts = 0 (step 225). ts = 0 means that the output torque of the engine 1 is increased to the target torque Ts in a stepwise manner. Following step 225, a torque curve T determined by the target torque Ts and time ts is set (step 230). Further, when torque is generated in the engine 1 so as to have this torque curve T, the waveform of the longitudinal acceleration a generated in the vehicle is calculated, and the peak value p is calculated (step 235). A waveform of the longitudinal acceleration a calculated based on the torque curve T in FIG. 5 is shown in FIG. The peak value p is shown in FIG. Further, “as” in the figure is a longitudinal acceleration generated in the vehicle when the engine 1 generates the target torque Ts and enters a steady state.

In step 235, in order to obtain the waveform of the longitudinal acceleration a generated in the vehicle from the torque curve T, a vehicle model as shown in FIG. 7 is used. The vehicle model of FIG. 7 outputs the vehicle longitudinal acceleration a (m / s ² ) with the output torque T (N · m) of the engine 1 as an input, and the rotational inertia I (kg · m ² ) of the flywheel, Drive shaft stiffness k (N · m / rad), tire damping coefficient c (N · m · s / rad), vehicle weight m (kg), tire radius R (m), gear ratio N, crank rotation angle θ1 (rad ) And the following equation (I) using the wheel rotation angle θ2 (rad).

  In the present embodiment, the above-described peak value p is obtained as a difference from the steady acceleration as. Based on the peak value p, a determination value pmax for determining whether the vehicle longitudinal vibration is within an allowable range is obtained from the map (step 240). The map used at this time is stored in advance in a ROM or the like in the ECU 15 as a three-dimensional map of the gear ratio, the engine speed Ne, and the target torque Ts. Note that the gear ratio of the transmission connected to the engine 1 is detected by a sensor in step 215 (or, if it is an automatic transmission, it is grasped by its control ECU).

  The greater the peak value p described above (or the greater the deviation from the steady acceleration as), the greater the vehicle longitudinal vibration. The above-described determination value pmax is set as a threshold value for determining whether or not the generated longitudinal vibration is acceptable. When the determination value pmax is obtained from the map, it is determined whether or not the peak value p calculated in step 235 is less than the determination value pmax (step 245). Here, when the peak value p is equal to or greater than the determination value pmax, the above-described time ts is increased by a predetermined increment (step 250), a torque curve is obtained again (step 230), and the peak value p is obtained from the acceleration waveform. Re-determination is performed, and the time ts is gradually increased until step 245 is affirmed.

  In the present embodiment, the peak value p is obtained as a difference from the steady acceleration as, and the determination in step 245 is performed based on the peak value p. That is, if the absolute value of the peak value p is P, it is determined that p = (P−as) <pmax, which is the same as determining that P <(pmax + as). In other words, it can be said that it is determined whether the absolute peak value P is less than the predetermined value (pmax + as) (in other words, whether it exceeds).

  Note that, as described above, the initial value of the time ts is 0, and it is determined from the case where the output torque is increased to the target torque Ts in a stepwise manner, and the vehicle longitudinal vibration is often unacceptable. However, by gradually increasing the time ts, it is possible to set the torque curve T that efficiently achieves both acceleration performance and longitudinal vibration suppression. However, the torque curve T obtained in the steps so far is for increasing the torque linearly up to the target torque Ts. Therefore, after step 245 is affirmed, the torque curve T is corrected to one that can more effectively achieve both acceleration performance and longitudinal vibration suppression.

  First, when step 245 is affirmed, the increment number i for the first division is set to the initial value 1 in order to calculate a further torque improvement by dividing the time ts into a plurality of steps (step 245). 255). The length of t1 here is set in consideration of an arithmetic unit in the ECU 15. The torque corresponding to the time t1 on the already calculated torque curve T is defined as T1 (see FIG. 5). The torque T1 is further increased, and it is determined whether or not the vehicle longitudinal vibration is still within the allowable range. At that time, first, Ti (here i = 1) is raised by a predetermined amount to correct the torque curve T (step 260). The corrected torque curve T is shown in FIG. As can be seen by comparing FIG. 5 and FIG. 8, T1 is raised.

  After step 260, the peak value p is calculated from the acceleration waveform as in step 235 described above (step 265). Then, pmax is obtained from the map as in step 240 (step 270), and based on this, the same determination as in step 245 is performed (step 275). However, in the map used in step 270, the torque Ti after raising is substituted in place of the torque target torque Ts substituted in the map used in step 240. The maps themselves are the same, only the torque values are different. Further, in the map search in step 270, it is preferable that the gear ratio and the engine speed Ne are detected again.

  If step 275 is positive, it can be determined that there is still a margin with respect to pmax (that is, the longitudinal vibration is within the allowable range even if the peak value p is still large), so Ti (here i = i = 1) is further raised (step 260), and steps 265 to 275 are repeated. Repeatedly increasing Ti gradually, the torque curve T can be corrected to achieve both the acceleration performance and the longitudinal vibration suppression efficiently. As described above, when step 260 to step 275 are repeatedly performed, step 275 is eventually denied. In this case, the Ti previous value is determined (step 280).

  Thereafter, based on the determined torque curve T (determined until time ti), the ignition timing SA and the throttle opening θth are determined (step 285), and torque control is started based on these (step 290). After step 290, it is determined whether or not ti has reached ts (step 295), and if not, i is incremented to determine the torque curve after undetermined ti (step 300), The control from step 260 is repeated (see FIG. 9). If ti has reached ts, the torque control in the flowcharts of FIGS. 2 and 3 ends.

  As described above, the length of ti is set in consideration of the calculation cycle in the ECU 15, and the next calculation of ti + 1 can be completed while the torque control up to ti is executed. Depending on the calculation capability, it may be possible to start actual torque control after completing all calculations up to ts. In this way, the torque curve is predicted, the longitudinal acceleration (front / rear vibration) is predicted from the torque curve, and the torque control is actually performed to generate the maximum torque in which the predicted peak value of the longitudinal acceleration does not exceed the allowable value. By doing so, acceleration performance and vehicle body longitudinal vibration suppression can be achieved in a well-balanced manner. In particular, in this embodiment, a further effect is obtained by subdividing the torque curve and repeatedly generating the maximum torque at which the predicted peak value of the longitudinal acceleration does not exceed the allowable value.

  Next, a second embodiment of the torque control device of the present invention will be described. Since the configuration of the engine 1 having the control device of the present embodiment is the same as that of the first embodiment (see FIG. 1) described above, a detailed description thereof is omitted here. FIG. 10 shows a flowchart of torque control by the control device of this embodiment.

  As shown in FIG. 10, first, as in the first embodiment described above, the accelerator position θ is detected by the accelerator position sensor 14 (step 1000), and the accelerator depression speed θ is integrated by time integration. / Dt is calculated to determine whether or not the accelerator depression speed dθ / dt exceeds a predetermined value α (step 1005). When step 1005 is negative, normal torque control for adjusting the output torque of the engine 1 is performed using the opening degree θth of the throttle valve 12 and the ignition timing SA as parameters (step 1010).

  On the other hand, when step 1005 is affirmed, in order to perform torque control of the engine 1 while balancing acceleration performance and vehicle body longitudinal vibration suppression, first, the engine speed Ne is determined by the crank position sensor 21 and the wheel speed sensor 24 is controlled. The vehicle speed v is detected, and the gear ratio is also detected (step 1015). Next, as in the first embodiment, the ECU 15 calculates the target torque Ts of the engine 1 from the map based on the accelerator opening θ detected in step 1000 and the engine speed Ne detected in step 1015 ( Step 1020).

  This target torque Ts is a torque that finally converges the output torque of the engine 1. Next, the longitudinal acceleration as generated in the vehicle when the engine 1 generates the target torque Ts and enters a steady state is calculated (step 1025). Here, when the steady acceleration as is calculated from the target torque Ts, the above-described first embodiment is also obtained by solving the equation using the above equation (I) using the vehicle model of FIG. 7 described above. It is the same as the form. After step 1025, the maximum torque Tmax that can be output is obtained from the map (step 1030). The map used at this time is stored in advance in a ROM or the like in the ECU 15 as a three-dimensional map of the gear ratio, the engine speed Ne, and the vehicle speed v.

  The maximum torque mentioned here is the engine output torque that is the upper limit that does not cause the vehicle (wheel) to slip. However, if slip does not occur even if the maximum torque that the engine 1 can output is output, the maximum torque means the maximum torque that the engine 1 can output. When the maximum torque Tmax is determined, the output torque T is set as the maximum torque Tmax (step 1035), and torque control is started based on this (step 1040). That is, as shown in FIG. 11A, the output torque T can be increased up to Tmax in a stepped manner.

  Since the torque control is started with the output torque T as the maximum torque Tmax, sufficient acceleration performance can be obtained. Simultaneously with the start of torque control (or continuously from before), measurement of the longitudinal acceleration a acting on the vehicle body is started by the acceleration sensor 22 (step 1045). Then, it is determined whether or not the measured acceleration a exceeds as + ε (step 1050). If it exceeds as + ε, the output torque T is once reduced (in this case, reduced to T = 0) on the assumption that the vehicle longitudinal vibration exceeds the allowable range (step 1055). ε is a minute value and ε = 0 is taken as an example, and FIGS. 11A and 11B show the relationship between the output torque T and the longitudinal acceleration a.

  Thus, by reducing the output torque T, vehicle longitudinal vibration can be suppressed. If the torque control is executed by simply increasing the output torque T to the maximum torque Tmax in a stepped manner as shown by the dotted line in FIG. 11A, it is shown by the dotted line in FIG. 11B. In addition, longitudinal vibration occurs in the vehicle. If the detected acceleration a exceeds as + ε, the output torque T is once reduced, so that the vehicle longitudinal vibration can be minimized as shown by the solid line in FIG.

  After step 1055, the process returns to step 1045, and control is executed again from the detection of acceleration. On the other hand, if step 1050 is negative and the detected longitudinal acceleration a does not exceed as + ε, it is determined whether the longitudinal acceleration a is below as−ε (step 1060). When the longitudinal acceleration a is less than as−ε, it can be determined that the output torque T is once reduced and the longitudinal acceleration generated in the vehicle is reduced. In this case, the output torque T is set to the target torque Ts (step 1065) so that the longitudinal acceleration a quickly converges to the steady acceleration as. After step 1065, the process returns to step 1045, and control is executed again from the detection of acceleration.

  If step 1060 is negative, it is determined whether or not the detected acceleration a has already converged to the steady acceleration as (step 1070). If step 1070 is affirmed, the torque control ends. If not, the output torque T at that time is maintained (Tmax, 0, or Ts), and the process returns to step 1045 to return the acceleration. Control is executed again from the detection.

  In step 1050 and step 1060 described above, ε is used to set a region that should be called a dead zone in the vicinity of the steady acceleration as. For example, a situation may occur in which the detected acceleration a fluctuates slightly and the upper side and the lower side change alternately across the steady acceleration as. In such a case, if the above-described ε is not used, the output torque T is frequently changed, resulting in rough control. Therefore, this is avoided by using ε described above. As described above, FIG. 11 shows a case where ε = 0 for easy understanding.

  As described above, sufficient acceleration performance is obtained by generating the maximum torque Tmax until the longitudinal acceleration a generated in the vehicle reaches a predetermined value (here, steady acceleration as [+ ε]), while obtaining sufficient acceleration performance. When the acceleration a reaches a predetermined value (here, steady acceleration as [−ε]), the output torque is decreased for a predetermined period to suppress the vehicle longitudinal vibration, thereby achieving a balance between acceleration performance and vehicle body longitudinal vibration suppression in a balanced manner. Can be made.

  The present invention is not limited to the embodiment described above. For example, in step 1055 of the flowchart of FIG. 10 described above, the output torque T is reduced to T = 0, but it may not be reduced to 0. For example, the output torque T may be 25% of the target torque Ts, or It may be determined according to the running state. However, the lowering of the output torque T is to suppress the longitudinal vibration of the vehicle, and it is effective if the output torque T is reduced below the target torque Ts.

  Further, when the output torque T is decreased, the starting point is when the detected acceleration a reaches the above-described steady acceleration as (in the above embodiment, the minute value ε is used for setting the dead zone). It is preferable to make it. Since the vehicle longitudinal acceleration a can eventually converge to the steady acceleration as, the vehicle longitudinal vibration can be effectively suppressed by reducing the output torque T using this value as a threshold value.

It is a block diagram which shows the structure of the internal combustion engine (engine) which has embodiment of the torque control apparatus of this invention. It is a flowchart (first half) of torque control in a first embodiment of a torque control device of the present invention. It is a flowchart (second half) of torque control in a first embodiment of a torque control device of the present invention. It is a map used at the time of target torque Ts calculation. It is a graph which shows a torque curve. It is a graph which shows a vehicle body longitudinal acceleration change. It is explanatory drawing which shows a vehicle model typically. It is a graph which shows a torque curve (after correction once). It is a graph which shows a torque curve (after 2 times correction). It is a flowchart of the torque control in 2nd embodiment of the torque control apparatus of this invention. (A) is a graph which shows a torque curve, (b) is a graph which shows a vehicle body longitudinal acceleration change.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine, 3 ... Injector, 6 ... Spark plug, 11 ... Air flow meter, 12 ... Throttle valve, 13 ... Accelerator pedal, 14 ... Accelerator position sensor (accelerator opening detection means), 15 ... ECU (torque control means / torque (Predicting means / acceleration predicting means / target torque calculating means), 16... Throttle motor, 17... Throttle positioning sensor, 21... Crank position sensor (rotational speed detecting means), 22.

Claims (3)

In a torque control device for an internal combustion engine that controls output torque of an internal combustion engine mounted on a vehicle,
An accelerator opening detecting means for detecting the amount of depression of the accelerator pedal;
A rotational speed detection means for detecting the rotational speed of the internal combustion engine;
Torque predicting means for predicting a torque curve of required torque based on the accelerator opening detected by the accelerator opening detecting means and the rotational speed detected by the rotational speed detecting means;
Acceleration prediction means for predicting longitudinal acceleration generated in the vehicle based on the torque curve predicted by the torque prediction means;
Torque control means for controlling an output torque of the internal combustion engine by controlling at least one of an intake air amount, an injected fuel amount, and an ignition timing;
The torque control means controls the output torque by adjusting the torque curve so as to generate a maximum torque within a range in which a peak value of longitudinal acceleration predicted by the acceleration prediction means does not exceed a predetermined allowable value. A torque control apparatus for an internal combustion engine characterized by the above. In a torque control device for an internal combustion engine that controls output torque of an internal combustion engine mounted on a vehicle,
Acceleration detecting means for detecting longitudinal acceleration generated in the vehicle;
Torque control means for controlling an output torque of the internal combustion engine by controlling at least one of an intake air amount, an injected fuel amount, and an ignition timing;
The torque control means generates the maximum torque until the longitudinal acceleration detected by the acceleration detecting means reaches a predetermined value, and outputs the output torque so as to decrease the output torque for a predetermined period after the longitudinal acceleration reaches the predetermined value. A torque control apparatus for an internal combustion engine characterized by adjusting the torque. Accelerator opening degree detecting means for detecting the depression amount of the accelerator pedal, rotational speed detecting means for detecting the rotational speed of the internal combustion engine, accelerator opening degree detected by the accelerator opening degree detecting means and the rotational speed detecting means A target torque calculating means for calculating a target torque based on the detected rotational speed,
The torque control means generates a maximum torque until the longitudinal acceleration detected by the acceleration detecting means reaches the longitudinal acceleration generated during steady running at the target torque, and after the longitudinal acceleration reaches the target torque, for a predetermined period. The torque control apparatus for an internal combustion engine according to claim 2, wherein the output torque is adjusted so as to reduce the engine torque to a target torque or less.

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