JP4496925B2 - Torque control device for internal combustion engine - Google Patents

Description

  The present invention relates to a torque control device for an internal combustion engine.

  A technique for suppressing the vibration in the longitudinal direction of the vehicle body that occurs as the vehicle accelerates by controlling the driving force (torque) of the internal combustion engine mounted on the vehicle is known (for example, see Patent Document 1). . When controlling the torque of the internal combustion engine for the purpose of suppressing such longitudinal vibrations of the vehicle body, the end timing of the torque control may be determined based on the timing at which the acceleration of the longitudinal vibrations of the vehicle body peaks. is there.

JP 2003-206775 A JP-A-6-257480 JP-A-5-162571

  For this reason, it is necessary to accurately obtain the above timing at which the acceleration of the longitudinal vibration of the vehicle body reaches a peak, but it has conventionally been difficult to accurately obtain this timing (actually, the acceleration of the vehicle is measured). If the acceleration sensor is used, the above timing can be obtained. In that case, however, the cost increases accordingly.

  The present invention has been made in view of the above points, and an object of the present invention is to determine the timing at which the acceleration of the longitudinal vibration of the vehicle body generated along with the acceleration of the vehicle reaches a peak, and based on the timing, the internal combustion engine In a torque control device for an internal combustion engine that adjusts torque, it is an object to provide a torque control device for an internal combustion engine that can determine the timing more accurately without using the acceleration sensor.

The present invention provides a torque control device for an internal combustion engine described in the claims as a means for solving the above-mentioned problems.

That is, the present invention obtains the timing of the acceleration reaches a peak of longitudinal vibrations of the vehicle body generated due to acceleration of the vehicle, the torque control system for an internal combustion engine for adjusting the torque of the internal combustion engine based on the same timing, the vehicle Is equipped with an automatic transmission with a torque converter, and when the acceleration of the longitudinal vibration of the vehicle body peaks, the rotational angular acceleration of the turbine of the vehicle torque converter first protrudes downward after the vehicle starts acceleration. A torque control device for an internal combustion engine that is obtained from a timing at which an extreme value is obtained is provided.

If the vehicle is equipped with a torque converter with automatic transmission is accelerated, the rotational speed of the torque converter turbine in the same vehicle (i.e., rotational speed) becomes that is raised, this time, the rotation of the turbine The value of angular acceleration vibrates. The inventors of the present application have found that the phase of this vibration is advanced by 180 ° compared to the phase of the acceleration of the longitudinal vibration of the vehicle body that occurs as the vehicle is accelerated.

The present invention takes advantage of this fact, and the acceleration of the longitudinal vibration of the vehicle body peaks from the timing when the rotational angular acceleration of the turbine of the torque converter of the vehicle takes an extreme value that first protrudes downward after the acceleration of the vehicle starts. In this way, the timing at which the acceleration of the longitudinal vibration of the vehicle body peaks can be obtained more accurately. As a result, the torque of the internal combustion engine can be controlled more appropriately.

If the vehicle is equipped with a manual transmission, the rotational angular acceleration of the crankshaft can be used instead of the rotational angular acceleration of the turbine of the torque converter .

The present invention uses an acceleration sensor in a torque control device for an internal combustion engine that obtains a timing at which acceleration of the longitudinal vibration of the vehicle body that occurs as the vehicle accelerates reaches a peak and adjusts the torque of the internal combustion engine based on the timing. it possible to more accurately determine the timing without an effect that result, it possible to more appropriately controlling the torque of the internal combustion engine.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram for explaining the present invention applied to a vehicle equipped with an automatic transmission with a torque converter.

  In the present embodiment, the driving force (torque) generated by the internal combustion engine 1 is first input to the torque converter 3 and then transmitted to the transmission (gear) 5 via the torque converter 3. The transmission 5 is connected to a drive shaft 7, and the torque is transmitted to the tire 9 through the drive shaft 7. The vibration generated in the torque transmission process is transmitted to the vehicle body 10.

  In the present embodiment, the internal combustion engine 1 is controlled by an electronic control unit (ECU) 11 including its generated torque, and the internal combustion engine 1 and the ECU 11 exchange signals necessary for control. The signal input from the internal combustion engine 1 to the ECU 11 includes a signal indicating the engine speed NE. The ECU 11 also receives a signal from an accelerator opening sensor 15 that is connected to the accelerator pedal 13 and detects the accelerator opening θ.

  Further, a turbine rotation speed sensor 17 for measuring the rotation speed Nt of the turbine 3 a of the torque converter 3 is provided on the output side of the torque converter 3. A signal from the turbine speed sensor 17 is also input to the ECU 11. Further, information on the shift position, that is, the gear ratio in the transmission 5 is also input to the ECU 11.

  In the present embodiment, in the configuration as described above, the vibration in the front-rear direction of the vehicle body 10 that occurs as the vehicle accelerates is suppressed by controlling the torque of the internal combustion engine 1. When the torque control of the internal combustion engine is performed for the purpose of suppressing the longitudinal vibration of the vehicle body as described above, the end timing of the torque control may be determined with reference to the timing at which the acceleration of the longitudinal vibration of the vehicle body peaks. Also in this embodiment, the end timing is the timing at which the acceleration of the longitudinal vibration of the vehicle body first peaks after the acceleration starts. Conventionally, the timing at which the acceleration of the longitudinal vibration peaks has been obtained accurately. Without an acceleration sensor, it was difficult. When an acceleration sensor is used, the cost increases accordingly.

  In the present embodiment, considering the above points, the fact found by the inventors of the present application, that is, the phase of vibration of the value of the rotational angular acceleration dNt of the turbine 3a of the torque converter 3 is equal to the longitudinal vibration of the vehicle body. Taking advantage of the fact that the phase of acceleration is 180 degrees ahead of the phase of the acceleration vibration, the timing at which the acceleration of the longitudinal vibration peaks is obtained more accurately without using an acceleration sensor, and the torque of the internal combustion engine is more appropriate. I try to control it. As a result, it is possible to more reliably suppress the longitudinal vibration of the vehicle body.

  That is, in this embodiment, control by the control routine shown in the flowchart of FIG. 2 is performed in order to suppress the longitudinal vibration of the vehicle body accompanying the acceleration of the vehicle. This control routine is executed by interruption every predetermined time by the ECU 11.

  When this control routine is started, first, at step 101, the measurement of the accelerator opening θ is started. Subsequently, at step 103, it is determined whether or not the change rate (dθ / dt) of the accelerator opening θ is larger than a predetermined reference value α. In this determination, it is determined whether or not high acceleration is required to cause the longitudinal vibration of the vehicle body to be suppressed by performing torque control, and the reference value α is used for this purpose. It is predetermined in consideration.

  If it is determined in step 103 that the change rate of the accelerator opening θ is equal to or less than the reference value α ((dθ / dt) ≦ α), acceleration is not requested or acceleration is requested. This is a case where the required degree of acceleration is low and it is considered that there is no longitudinal vibration of the vehicle body that needs to be suppressed by torque control. In this case, this control routine is temporarily terminated. Become.

  On the other hand, if it is determined in step 103 that the change rate of the accelerator opening θ is larger than the reference value α ((dθ / dt)> α), the requested degree of acceleration is high, and torque control is performed. This is a case where it is considered that the longitudinal vibration of the vehicle body that needs to be suppressed occurs. Therefore, in this case, the process proceeds to step 105, where torque control for suppressing the longitudinal vibration of the vehicle body is started. Specifically, this torque control includes, for example, ignition timing retardation control, throttle valve opening adjustment control, and the like, and is usually torque reduction control.

  When the torque control is started in step 105, the process proceeds to step 107, and measurement of the rotational speed Nt of the turbine 3a of the torque converter 3 is started. In the subsequent step 109, the rotational angular acceleration dNt of the turbine 3a of the torque converter 3 is calculated from the rotational speed Nt. This calculation is performed by the ECU 11.

  By the way, in consideration of the fact that the vibration phase of the value of the rotational angular acceleration dNt is 180 ° ahead of the vibration phase of the acceleration G of the longitudinal vibration of the vehicle body, the torque control is finished in this embodiment. It can be said that the timing at which the acceleration of the longitudinal vibration of the vehicle body, which is the power timing, first peaks after the acceleration starts is the timing at which the rotational angular acceleration dNt takes the extreme value that first protrudes downward after the acceleration starts.

  That is, FIG. 3 shows the change with time after the start of acceleration of the acceleration G of the longitudinal vibration of the vehicle body, the rotational speed Nt of the turbine 3a, and the rotational angular acceleration dNt of the turbine 3a in order from the top. As shown in the figure, the timing at which the acceleration G of the longitudinal vibration of the vehicle body first peaks after the acceleration starts is equal to the timing t1 at which the rotational angular acceleration dNt takes the extreme value that first protrudes downward after the acceleration starts. .

  Therefore, in the following step 111, it is determined whether or not the rotational angular acceleration dNt has become an extreme value that protrudes downward. That is, it is determined by this determination whether or not the acceleration of the longitudinal vibration of the vehicle body has reached the first peak time after the start of acceleration, that is, whether or not the above torque control should be terminated.

  If it is determined in step 111 that the rotational angular acceleration dNt is not an extreme value that protrudes downward, it is not the timing at which the torque control should be terminated yet, so the control returns to step 105. Thus, the torque control is continued. On the other hand, if it is determined in step 111 that the rotational angular acceleration dNt has reached an extreme value that protrudes downward, it is the time when the torque control should be terminated, and therefore control proceeds to step 113 and The torque control is terminated and this control routine is terminated.

  As described above, in the present embodiment, the timing at which the acceleration of the longitudinal vibration of the vehicle body peaks is obtained from the timing at which the rotational angular acceleration of the turbine 3a takes the extreme value that first protrudes downward after acceleration starts. The torque of the internal combustion engine is adjusted based on the timing. That is, in this embodiment, the timing at which the acceleration of the longitudinal vibration peaks is obtained accurately without using an acceleration sensor, and the torque of the internal combustion engine is adjusted based on the timing. As a result, the torque of the internal combustion engine can be controlled more appropriately.

Next, reference embodiments related to the present invention will be described. This reference embodiment can be implemented in the configuration as shown in FIG. 1 and has many parts in common with the above-described embodiment. In principle, description of these common parts is omitted.

In this reference embodiment, the phase of vibration at the rotational speed Nt of the turbine 3a of the torque converter 3 generated when the vehicle is accelerated is advanced by 90 ° compared to the phase of vibration of the acceleration G of the longitudinal vibration of the vehicle body. (See FIG. 3), the timing at which the acceleration of the longitudinal vibration peaks, the timing at which the rotational speed Nt takes an extreme value that first protrudes upward after the start of acceleration, and the driving system of the vehicle It is obtained from the torsional frequency, and the torque of the internal combustion engine is adjusted based on the timing.

Hereinafter, a description will be given of a control carried out in the present reference embodiment with reference to FIG. Figure 4 is a flowchart showing a control routine of the control performed in the present reference embodiment. Similar to the control routine (FIG. 2) of the above-described embodiment, this control routine is also executed by the ECU 11 by interruption every predetermined time.

  When this control routine starts, first, in step 201, measurement of the accelerator opening θ is started. The control in step 201 is the same as the control in step 101 described above. In addition, the control in steps 203, 205, and 207 following step 201 is the same as the control in steps 103, 105, and 107, respectively, and a description thereof is omitted here.

  In step 209 following step 207, it is determined whether or not the rotational speed Nt of the turbine 3a of the torque converter 3 has reached an extreme value that is convex upward. Considering that the vibration phase of the turbine 3a at the rotational speed Nt is advanced by 90 ° compared to the vibration phase of the acceleration G of the longitudinal vibration of the vehicle body, this determination results in a peak acceleration of the longitudinal vibration of the vehicle body. It is determined whether or not the timing is 90 ° earlier than the above timing, that is, whether the timing is ¼ of the period T of the vibration.

  If it is determined in step 209 that the rotational speed Nt of the turbine 3a is not an extreme value that is convex upward, the control returns to step 205 and torque control is continued. On the other hand, if it is determined in step 209 that the rotational speed Nt of the turbine 3a has reached an extreme value that is convex upward, the control proceeds to step 211.

In step 211, the torsional frequency f of the drive system of the vehicle is obtained. In the present reference embodiment, the torsional vibration frequency f is the engine speed NE, and the gear ratio in the transmission 5, the speed ratio S (S = Nt / NE) in the torque converter 3 as an argument, the torsional vibration frequency f A map for which is required is prepared in advance, and is determined based on this.

  The torsional frequency f of the vehicle drive system is considered to be the same as the vibration frequency of the acceleration of the longitudinal vibration of the vehicle body. Therefore, by calculating the reciprocal of the torsional frequency f, the longitudinal vibration of the vehicle body is obtained. The acceleration vibration period T can be obtained (T = 1 / f).

  In step 213 following step 211, it is determined whether or not a quarter cycle has elapsed since it was determined in step 209 that the rotation speed Nt had taken an extreme value that is convex upward. As is clear from the description so far, the determination here is a determination as to whether or not the acceleration of the longitudinal vibration of the vehicle body has reached the first peak after the start of acceleration, that is, the torque control is terminated. This is a determination as to whether or not the timing has come.

If it is determined in step 213 that a quarter cycle has elapsed since the extreme value at which the rotational speed Nt is convex upward, the control proceeds to step 215, where the rotational speed Nt is increased. When it is determined that a quarter period has not elapsed since the extreme value that is convex is taken, the determination in step 213 is repeated again while the torque control is being performed. In other words, in this reference embodiment, the process proceeds to step 215 when a quarter cycle has elapsed since the rotation number Nt took an extreme value that is convex upward. When the control proceeds to step 215, the torque control is terminated there and the present control routine is terminated.

In this reference embodiment, as described above, the timing at which the acceleration has a peak of the longitudinal vibrations exactly sought without using the acceleration sensor, so that the torque of the internal combustion engine is adjusted based thereon. As a result, the torque of the internal combustion engine can be appropriately controlled.

Next, another reference embodiment will be described. In addition, this reference embodiment also has many parts which are common with embodiment mentioned above and reference embodiment, and abbreviate | omits description in principle about these common parts.

This reference embodiment can also be basically implemented in the configuration as shown in FIG. 1, but in this reference embodiment, in the configuration shown in FIG. 1, the rotation of a vehicle wheel (ie, tire) is performed. A wheel rotation number sensor (not shown) for measuring the number Nc is provided.

This reference embodiment utilizes the fact that the vibration phase of the wheel rotational speed Nc generated when the vehicle is accelerated matches the vibration phase of the acceleration of the longitudinal vibration of the vehicle body. Is determined from the timing at which the rotational speed Nc takes an extreme value that first protrudes upward after acceleration starts, and the torque of the internal combustion engine is adjusted based on the timing.

Hereinafter, a description will be given of a control carried out in the present reference embodiment with reference to FIG. Figure 5 is a flowchart showing a control routine of the control performed in the present reference embodiment. This control routine is also executed by interruption every predetermined time by the ECU 11 as in the control routines (FIGS. 2 and 4) of the embodiment and the reference embodiment described above.

  When this control routine starts, first, at step 301, the measurement of the accelerator opening θ is started. The control in step 301 is the same as the control in steps 101 and 201 described above. Further, the control in Steps 303 and 305 following Step 301 is the same as the control in Step 103 or Step 203 and Step 105 or Step 205 described above, respectively, and description thereof is omitted here.

When torque control is started in step 305, control proceeds to step 307, and measurement of the rotational speed Nc of the wheel is started. In step 309 subsequent to step 307, it is determined whether or not the rotation speed Nc of the wheel is an extreme value that is convex upward. As described above, the vibration phase of the rotational speed Nc of the wheel coincides with the vibration phase of the acceleration of the longitudinal vibration of the vehicle body. Therefore, the acceleration of the longitudinal vibration of the vehicle body first peaks after the acceleration starts by the determination here. It is determined whether or not the timing is reached. In the reference embodiment, this is a determination as to whether or not it is time to end the torque control.

  If it is determined in step 309 that the rotational speed Nc is not an extreme value that is convex upward, it is not the timing at which the torque control should be terminated yet, so the control returns to step 305. The torque control is continued. On the other hand, if it is determined in step 309 that the rotational speed Nc has reached an extreme value that is convex upward, it is the time when the torque control should be terminated, and therefore the control proceeds to step 311 and the torque is increased. The control is terminated and this control routine ends.

In this reference embodiment, as described above, the timing at which the acceleration has a peak of the longitudinal vibrations exactly sought without using the acceleration sensor, so that the torque of the internal combustion engine is adjusted based thereon. As a result, the torque of the internal combustion engine can be appropriately controlled.

In the above, the case of a vehicle equipped with an automatic transmission with a torque converter has been described as an example. However , the same idea can be applied to a vehicle equipped with a manual transmission , for example. Although detailed description will be omitted because it seems to be clear from the above description, in this case, the value corresponding to the rotational speed Nt of the torque converter turbine and the rotational angular acceleration dNt in the above-described embodiment is a shift. The rotational speed of the input shaft of the machine and its rotational angular acceleration are used. More specifically, for example, the number of rotations of the crankshaft and the rotational angular acceleration thereof can be used as values representing these. In addition, for the torsional frequency of the drive system, for example, a map for obtaining the torsional frequency is prepared in advance using the engine speed and the gear ratio in the transmission as arguments. .

FIG. 1 is a diagram for explaining the present invention applied to a vehicle equipped with an automatic transmission with a torque converter. FIG. 2 is a flowchart showing a control routine of torque control implemented in one embodiment of the present invention. FIG. 3 shows changes over time after the start of acceleration for each of acceleration G of longitudinal vibration of the vehicle body, rotational speed Nt of the turbine of the torque converter, and rotational angular acceleration dNt of the turbine. FIG. 4 is a flowchart showing a control routine for torque control performed in the reference embodiment of the present invention. FIG. 5 is a flowchart showing a control routine of torque control performed in another reference embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 3 Torque converter 3a Turbine 5 Transmission (gear)
7 Drive shaft 9 Tire 10 Car body 11 Electronic control unit 17 Turbine speed sensor

Claims (1)

In a torque control device for an internal combustion engine that obtains a timing at which acceleration of the longitudinal vibration of the vehicle body that occurs as the vehicle accelerates reaches a peak and adjusts the torque of the internal combustion engine based on the timing
When the vehicle is equipped with an automatic transmission with a torque converter and the acceleration of the longitudinal vibration of the vehicle body reaches a peak, the rotational angular acceleration of the turbine of the vehicle's torque converter is first reduced after the acceleration of the vehicle starts. A torque control device for an internal combustion engine, which is obtained from a timing at which an extreme value that is convex is taken.

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